This paper examines the agglomeration and accretion of drill cuttings in water-based drilling fluids. Experimental results are presented on various outcrop shales to analyze the effect that cuttings type and morphology have on agglomeration. Possible mechanisms linked to clay kinetic hydration and plastic deformation are discussed. Test results on various polymer chemistries show that more hydrophobic polymers reduce cuttings agglomeration. Additives that form hydrophobic films on cuttings and steel surfaces are also shown to reduce agglomeration. Careful selection of drilling fluid components can help mitigate cuttings agglomeration and thus improve water-based drilling fluid performance.
Highly inhibitive water based fluid system provides superioramrhaggag
The document summarizes the development and testing of a new highly inhibitive water-based drilling fluid system for drilling in reactive shale formations. The new system significantly reduces clay dispersion, hydration, and accretion compared to existing systems. It consists of four main components - a shale inhibitor, encapsulator, anti-accretion agent, and fluid loss control agent. Laboratory tests show the new system performs better than other water-based systems in inhibiting bentonite swelling, maintaining high bulk hardness of shale cuttings, achieving high slake durability test recoveries, and producing little to no accretion on steel bars. The new system provides an environmentally friendly alternative to oil-based muds for drilling in reactive shales.
Fabrication of super-hydrophobic surfaces for enhanced stone protection.pdfAwais44108
This document discusses research on modifying commercial siloxane stone protective compositions by adding silica nanoparticles to enhance stone protection. The key findings are:
- Adding silica nanoparticles to a siloxane protective composition and applying it to white Greek marble surfaces resulted in the formation of micron-sized protrusions made of nanoparticle aggregates. This altered the surface morphology and created a dual micro-nano roughness.
- This dual roughness strongly increased the hydrophobicity of the treated marble surfaces, rendering them super-hydrophobic (water contact angle over 150 degrees) at a silica nanoparticle concentration of 1% weight per volume.
- Other stone protection properties like water vapor permeability, water absorption, and effects on
IPANEX is a liquid admixture added to concrete to make it waterproof by densifying its microstructure. It works by controlling hydration to produce a more homogeneous, fine-grained structure with smaller, more tortuous pores that restrict water penetration. Testing shows IPANEX concrete has significantly reduced permeability and chloride ion ingress. It provides advantages like increased strength, durability, corrosion resistance and waterproofness without organic chemicals that could degrade over time. IPANEX is recommended for applications requiring impermeable concrete under water pressure like foundations, tanks, and marine structures.
IRJET- Effect of Sea Water and Strength of ConcreteIRJET Journal
This document describes an experimental study on the effect of sea water and fresh water on the strength of concrete. 27 concrete specimens (cubes, cylinders, beams) were cast and cured using sea water, and another 27 specimens were cast and cured using fresh water. The specimens were tested for compressive strength, split tensile strength, and flexural strength at 7, 14, and 28 days. The study aims to investigate using sea water for mixing and curing concrete as an alternative to fresh water, which is scarce in some coastal areas. The results of the experiment will be presented to analyze how sea water affects the different strengths of concrete compared to using fresh water.
Flexible Drilling Fluid Formulation and Applicationjerianasmith
"Generic drilling fluids with well known attributes are used for drilling in many areas. Many times there is a need to enhance these fluids to perform in order to achieve a critical drilling objective. A number of additives are available for specific purposes. An additive which improves shale stability, reduces high temperature-high pressure filtrate, and provides lubricity is a good
example."
Flatline the alkali-silica reaction (ASR) in concrete using pumice-blended cement…at a cost of just pennies per yard. Quantifiable performance backed by ASTM-standard research.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The article is devoted to the problem of limiting water inflow in a production well.
The authors consider the main features of the reservoir, which contribute to
premature flooding. This paper presents the basic classification of plugging selective
compositions, outlines the advantages and disadvantages of each type. Gel composed
of carboxymethylcellulose, chromium acetate and copper sulfate was developed for
water production restriction. An alternative way was offered to determine the optimal
concentrations of plugging compositions on the change of the total porosity and x-ray
density measured in the x-ray tomograph. Dynamics of the effective viscosity on the
magnitude of the gap, simulating the fracture was obtained – the viscosity decreases
logarithmically. Filtration experiments confirmed the selective properties of the gelforming
composition
Highly inhibitive water based fluid system provides superioramrhaggag
The document summarizes the development and testing of a new highly inhibitive water-based drilling fluid system for drilling in reactive shale formations. The new system significantly reduces clay dispersion, hydration, and accretion compared to existing systems. It consists of four main components - a shale inhibitor, encapsulator, anti-accretion agent, and fluid loss control agent. Laboratory tests show the new system performs better than other water-based systems in inhibiting bentonite swelling, maintaining high bulk hardness of shale cuttings, achieving high slake durability test recoveries, and producing little to no accretion on steel bars. The new system provides an environmentally friendly alternative to oil-based muds for drilling in reactive shales.
Fabrication of super-hydrophobic surfaces for enhanced stone protection.pdfAwais44108
This document discusses research on modifying commercial siloxane stone protective compositions by adding silica nanoparticles to enhance stone protection. The key findings are:
- Adding silica nanoparticles to a siloxane protective composition and applying it to white Greek marble surfaces resulted in the formation of micron-sized protrusions made of nanoparticle aggregates. This altered the surface morphology and created a dual micro-nano roughness.
- This dual roughness strongly increased the hydrophobicity of the treated marble surfaces, rendering them super-hydrophobic (water contact angle over 150 degrees) at a silica nanoparticle concentration of 1% weight per volume.
- Other stone protection properties like water vapor permeability, water absorption, and effects on
IPANEX is a liquid admixture added to concrete to make it waterproof by densifying its microstructure. It works by controlling hydration to produce a more homogeneous, fine-grained structure with smaller, more tortuous pores that restrict water penetration. Testing shows IPANEX concrete has significantly reduced permeability and chloride ion ingress. It provides advantages like increased strength, durability, corrosion resistance and waterproofness without organic chemicals that could degrade over time. IPANEX is recommended for applications requiring impermeable concrete under water pressure like foundations, tanks, and marine structures.
IRJET- Effect of Sea Water and Strength of ConcreteIRJET Journal
This document describes an experimental study on the effect of sea water and fresh water on the strength of concrete. 27 concrete specimens (cubes, cylinders, beams) were cast and cured using sea water, and another 27 specimens were cast and cured using fresh water. The specimens were tested for compressive strength, split tensile strength, and flexural strength at 7, 14, and 28 days. The study aims to investigate using sea water for mixing and curing concrete as an alternative to fresh water, which is scarce in some coastal areas. The results of the experiment will be presented to analyze how sea water affects the different strengths of concrete compared to using fresh water.
Flexible Drilling Fluid Formulation and Applicationjerianasmith
"Generic drilling fluids with well known attributes are used for drilling in many areas. Many times there is a need to enhance these fluids to perform in order to achieve a critical drilling objective. A number of additives are available for specific purposes. An additive which improves shale stability, reduces high temperature-high pressure filtrate, and provides lubricity is a good
example."
Flatline the alkali-silica reaction (ASR) in concrete using pumice-blended cement…at a cost of just pennies per yard. Quantifiable performance backed by ASTM-standard research.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The article is devoted to the problem of limiting water inflow in a production well.
The authors consider the main features of the reservoir, which contribute to
premature flooding. This paper presents the basic classification of plugging selective
compositions, outlines the advantages and disadvantages of each type. Gel composed
of carboxymethylcellulose, chromium acetate and copper sulfate was developed for
water production restriction. An alternative way was offered to determine the optimal
concentrations of plugging compositions on the change of the total porosity and x-ray
density measured in the x-ray tomograph. Dynamics of the effective viscosity on the
magnitude of the gap, simulating the fracture was obtained – the viscosity decreases
logarithmically. Filtration experiments confirmed the selective properties of the gelforming
composition
This document discusses various types of formation damage that can occur including plugging by solid particles, plugging by formation solids, clay swelling, dispersion of clayey platelets, water block, emulsion formation, precipitation of inorganic scales, precipitation related to acidizing, mechanical damage, paraffin deposition, precipitation of asphaltene, wettability alteration, reduced relative permeability, sludge formation, damage by bacteria, polymer invasion, and gas breakout. Formation damage refers to any process that reduces permeability in the formation near the wellbore and decreases productivity over time. Common causes include invasion of foreign solids or fluids, changes in wettability, mineral precipitation, and bacterial growth. Proper design of completion and stimulation methods
This document analyzes the genetic factors that can lead to low resistivity reservoirs. It identifies six main factors: 1) low amplitude structure where differentiation of oil and water is poor, leading to high water saturation and low resistivity; 2) complex pore structure that increases fixed water content and decreases resistivity; 3) additional electrical conductivity from clays like montmorillonite that reduces resistivity; 4) thin sand-mud interlayers that limit logging tool resolution; 5) reservoirs containing conductive minerals like pyrite; and 6) low salinity formation water enhancing clay conductivity effects. The document concludes more research is needed on logging evaluation and identification methods for low resistivity reservoirs.
IRJET- Effect of Salt Water on Compressive Strength, Flexural Strength and Du...IRJET Journal
1. The study examines the effect of salt water on the compressive strength, flexural strength, and durability of concrete and cement mortar.
2. Concrete cubes, beams, and mortar cubes were cast and cured with both potable water and salt water to compare results.
3. Tests were performed on the specimens at various ages to determine compressive strength, flexural strength, and carbonation depth as a measure of durability. The results showed that compressive strength and flexural strength increased with the use of salt water, while durability decreased.
This document discusses self-curing or internal curing concrete, which provides internal water reservoirs through the use of materials like lightweight aggregates or super absorbent polymers to hydrate cement particles. Proper curing is important for concrete to develop strength and durability. Self-curing concrete reduces the need for external curing and can perform better in areas without sufficient water for curing. The document examines using polyvinyl alcohol as a self-curing agent and finds that it helps retain water in concrete and reduces weight loss compared to conventional mixes without compromising strength. Self-curing concrete offers advantages like reduced cracking, permeability and improved durability.
This document summarizes alkali-silica reaction (ASR) in concrete. It defines ASR as a chemical reaction between reactive silica in aggregates and alkalis in cement paste that causes expansion and cracking over time. The key requirements for ASR are a sufficiently high alkali content in cement, reactive aggregates, and available water. Common symptoms of ASR include map or pattern cracking and swelling concrete. Methods to prevent ASR include limiting moisture, selecting non-reactive aggregates, minimizing alkalis in cement, and using mineral admixtures like fly ash.
IRJET- To Study Properties of Concrete by Replacing Fresh Water with Treated ...IRJET Journal
This document studies using treated waste water from various sources in concrete as an alternative to fresh water. It analyzes the chemical properties of different types of treated waste water and tests their impact on the properties and strength of cement and concrete. The results show that treated sewage waste water has little to no negative impact on concrete strength. In some cases, concrete made with treated sewage water showed improved strength over time compared to concrete made with fresh water. The study concludes that using treated waste water in concrete can conserve natural fresh water resources while not negatively affecting concrete quality.
IRJET- Comparative Study on the Use of Clay and Cemented Clay as Landfill Lin...IRJET Journal
This document presents a comparative study on the use of clay and cement-stabilized clay as landfill liner materials. It describes how two reactors were set up, with one using clay and the other using cement-stabilized clay as liners. Leachate was synthetically prepared and passed through the liners. Laboratory analysis was conducted on the leachate before and after passing through the liners to analyze pH, turbidity, chloride content, and COD over a 28 day period. The study found that both clay and cement-stabilized clay were able to significantly reduce pollutants in the leachate, with the cement-stabilized clay performing slightly better at removing turbidity and COD.
IRJET- Analysis of Integral Crystalline Waterproofing Technology for ConcreteIRJET Journal
This document analyzes the integral crystalline waterproofing technology used for concrete. It discusses how traditional external waterproofing methods like coatings deteriorate over time, while internal crystalline waterproofing provides a more durable solution by plugging pores and cracks with non-soluble crystal formations that become part of the concrete structure. The document then examines how crystalline admixtures use chemical diffusion and reaction to fill voids within the concrete through a pore-blocking mechanism. This integral waterproofing approach makes the concrete more impervious to water and chemical ingress compared to external membranes or coatings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Effect of fly ash on the rheological and filtration properties of water based...eSAT Journals
Abstract An experimental investigation was carried out to study the effect of fly ash on the rheological and filtration properties of water based drilling fluids with the objective of the development of environmentally acceptable non-damaging and inhibitive drilling fluid system to drill sensitive formations. Initially, different drilling fluids combinations were prepared using carboxy methyl cellulose (low viscosity grade), polyanionic cellulose, xanthan gum, and potassium chloride. The rheological properties as well as filtration properties of these drilling fluids were measured by API recommended methods. These drilling fluids show very good rheological behavior but poor filtration loss characteristics. When fly ash was added in these drilling fluid combinations, a nanoparticles fluid system was established which has better control on filtration properties without affecting the rheological properties and has good potential for the drilling of sensitive formations. Index Terms: Filtrate Loss Properties, Rheological Properties, Wellbore Instability, Inhibitive Drilling Fluid, Nanoparticles, Shale.
IRJET - Shrinkage Crack Study due to Lead Contamination in Bentonite ClayIRJET Journal
1. The document studies the effect of lead contamination on the shrinkage cracking of bentonite clay. Bentonite clay samples contaminated with varying percentages of lead (0-0.1%) were tested.
2. The results showed that with increasing lead concentration, the consistency limits (liquid limit and plastic limit) of the bentonite clay decreased. The shrinkage limit was not significantly affected. Hydraulic conductivity increased with increasing lead concentration.
3. Digital image processing was used to analyze the crack patterns of the contaminated bentonite clay samples. The crack intensity factor, which is the ratio of crack surface area to total surface area, increased with higher lead contamination levels.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Functionalized Ceramic Membranes for the Separation of Organics from Raw Wate...Samuel Maguire-Boyle
This patent application describes functionalized ceramic membranes for separating organics from raw water with reduced fouling. It specifically describes coating ceramic membranes, such as silicon carbide membranes, with hydrophilic functional groups to make them more hydrophilic and resistant to fouling. This functionalization process allows the membranes to have larger pores and operate at lower pressures than existing membranes, while maintaining separation performance and limiting fouling, scaling, and permeability reductions.
IRJET- Comparative Evaluation of Bentonite Soil with Ordinary Clay for Contro...IRJET Journal
The document evaluates the use of bentonite-clay mixtures as liners in landfills to control leachate movement. It analyzes the physical properties of clay mixed with 2.5%, 5%, and 7.5% bentonite by weight. The mixtures showed reduced hydraulic conductivity, increased shear strength, and decreased compressibility compared to clay alone. This makes the mixtures more effective long-term barriers against leachate. The document also examines the chemical composition of leachate from a landfill site and how it interacts with the bentonite-clay liners.
Chemical admixtures are added to concrete to modify properties in either the plastic or hardened state. There are two main types - chemical admixtures and mineral admixtures. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Plasticizers and superplasticizers disperse cement particles, allowing a reduction in water content while maintaining workability. Superplasticizers can reduce water by up to 30% compared to 15% for plasticizers. Admixtures are used to achieve desired properties, maintain quality during placement and curing, overcome issues, and reduce concrete costs.
This document discusses the effects of salt water on concrete and provides recommendations for designing concrete that will be exposed to seawater. It notes that seawater contains salts that can deteriorate concrete through processes like sulfate attack, lime leaching, alkali-aggregate expansion, and corrosion of reinforcing steel. It recommends using low permeability concrete to limit these effects, and controlling key parameters like water-cement ratio, cement type, use of air-entraining agents, and concrete cover over reinforcing steel. The document provides tables with guidelines on these parameters and recommends repair methods that involve removing deteriorated concrete, cleaning reinforcing steel, and applying a protective barrier between the concrete and salt water.
IRJET - Variation of Cumulative Water Absorption in Concrete CubesIRJET Journal
This document summarizes research on the variation of cumulative water absorption in concrete cubes. It discusses how water absorption and permeability affect the durability of concrete structures. The researchers conducted experiments with 72 concrete cubes containing different concrete mixtures to evaluate the effectiveness of cumulative water absorption. The results showed that cumulative water absorption decreases with decreasing water absorption and increases with increasing water absorption rate. Cumulative absorption also decreases with increasing aggregate content and compressive strength but increases with higher water-cement ratios and over time. The sorptivity coefficient, which indicates water penetration rate, decreases with higher compressive strength and cumulative absorption.
Water quality has a significant impact on concrete strength. Impurities like chlorides, sulfates, and dissolved solids can reduce strength if present in high concentrations. Testing the compressive strength of concrete made with local water compared to distilled water determines if the local water is suitable. While seawater reduces early strength by 10-15% and may cause corrosion of reinforcement, it can be used for unreinforced concrete if the mix is redesigned. However, seawater is prohibited for reinforced or prestressed concrete per current Indian standards due to corrosion risks.
Seth Czaplewski proposes recycling unused clay materials and broken ceramics by incorporating them into new ceramic works or converting them into biochar. Some materials that can be recycled include clay abandoned in studios, contaminated clay, excavated clay from other projects, wad and wash from ceramic production, and unwanted or broken pots. Biochar is a charcoal-like material produced by heating biomass in low-oxygen conditions that can sequester carbon in soil for thousands of years and improve soil quality and plant growth. By recycling clay wastes and converting ceramics into biochar, Czaplewski aims to both reduce ceramic waste and educate the public about sustainable practices.
NEW RAW MATERIALS FOR PAPER PULP (the book)Mostafa Ahmad
This document provides acknowledgements and thanks to various individuals who contributed to the research project. It thanks Allah, the research supervisor Prof. Dr. Mamdouh M. Nassar and other professors at Minia University in Egypt for their guidance and support of the project. It also thanks other individuals who provided assistance with laboratory work, research contacts, and information collection. The document was completed in El-Minia, Egypt in 2016 by the listed authors.
Mary Frank is a significant influence on the artist. Frank sculpts psychologically complex figurative ceramic sculptures that break new ground in construction methods and the manipulation of clay slabs. Frank's work deals with themes of birth, death, sexuality, and sensory experiences through powerful female figures.
This document discusses various types of formation damage that can occur including plugging by solid particles, plugging by formation solids, clay swelling, dispersion of clayey platelets, water block, emulsion formation, precipitation of inorganic scales, precipitation related to acidizing, mechanical damage, paraffin deposition, precipitation of asphaltene, wettability alteration, reduced relative permeability, sludge formation, damage by bacteria, polymer invasion, and gas breakout. Formation damage refers to any process that reduces permeability in the formation near the wellbore and decreases productivity over time. Common causes include invasion of foreign solids or fluids, changes in wettability, mineral precipitation, and bacterial growth. Proper design of completion and stimulation methods
This document analyzes the genetic factors that can lead to low resistivity reservoirs. It identifies six main factors: 1) low amplitude structure where differentiation of oil and water is poor, leading to high water saturation and low resistivity; 2) complex pore structure that increases fixed water content and decreases resistivity; 3) additional electrical conductivity from clays like montmorillonite that reduces resistivity; 4) thin sand-mud interlayers that limit logging tool resolution; 5) reservoirs containing conductive minerals like pyrite; and 6) low salinity formation water enhancing clay conductivity effects. The document concludes more research is needed on logging evaluation and identification methods for low resistivity reservoirs.
IRJET- Effect of Salt Water on Compressive Strength, Flexural Strength and Du...IRJET Journal
1. The study examines the effect of salt water on the compressive strength, flexural strength, and durability of concrete and cement mortar.
2. Concrete cubes, beams, and mortar cubes were cast and cured with both potable water and salt water to compare results.
3. Tests were performed on the specimens at various ages to determine compressive strength, flexural strength, and carbonation depth as a measure of durability. The results showed that compressive strength and flexural strength increased with the use of salt water, while durability decreased.
This document discusses self-curing or internal curing concrete, which provides internal water reservoirs through the use of materials like lightweight aggregates or super absorbent polymers to hydrate cement particles. Proper curing is important for concrete to develop strength and durability. Self-curing concrete reduces the need for external curing and can perform better in areas without sufficient water for curing. The document examines using polyvinyl alcohol as a self-curing agent and finds that it helps retain water in concrete and reduces weight loss compared to conventional mixes without compromising strength. Self-curing concrete offers advantages like reduced cracking, permeability and improved durability.
This document summarizes alkali-silica reaction (ASR) in concrete. It defines ASR as a chemical reaction between reactive silica in aggregates and alkalis in cement paste that causes expansion and cracking over time. The key requirements for ASR are a sufficiently high alkali content in cement, reactive aggregates, and available water. Common symptoms of ASR include map or pattern cracking and swelling concrete. Methods to prevent ASR include limiting moisture, selecting non-reactive aggregates, minimizing alkalis in cement, and using mineral admixtures like fly ash.
IRJET- To Study Properties of Concrete by Replacing Fresh Water with Treated ...IRJET Journal
This document studies using treated waste water from various sources in concrete as an alternative to fresh water. It analyzes the chemical properties of different types of treated waste water and tests their impact on the properties and strength of cement and concrete. The results show that treated sewage waste water has little to no negative impact on concrete strength. In some cases, concrete made with treated sewage water showed improved strength over time compared to concrete made with fresh water. The study concludes that using treated waste water in concrete can conserve natural fresh water resources while not negatively affecting concrete quality.
IRJET- Comparative Study on the Use of Clay and Cemented Clay as Landfill Lin...IRJET Journal
This document presents a comparative study on the use of clay and cement-stabilized clay as landfill liner materials. It describes how two reactors were set up, with one using clay and the other using cement-stabilized clay as liners. Leachate was synthetically prepared and passed through the liners. Laboratory analysis was conducted on the leachate before and after passing through the liners to analyze pH, turbidity, chloride content, and COD over a 28 day period. The study found that both clay and cement-stabilized clay were able to significantly reduce pollutants in the leachate, with the cement-stabilized clay performing slightly better at removing turbidity and COD.
IRJET- Analysis of Integral Crystalline Waterproofing Technology for ConcreteIRJET Journal
This document analyzes the integral crystalline waterproofing technology used for concrete. It discusses how traditional external waterproofing methods like coatings deteriorate over time, while internal crystalline waterproofing provides a more durable solution by plugging pores and cracks with non-soluble crystal formations that become part of the concrete structure. The document then examines how crystalline admixtures use chemical diffusion and reaction to fill voids within the concrete through a pore-blocking mechanism. This integral waterproofing approach makes the concrete more impervious to water and chemical ingress compared to external membranes or coatings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Effect of fly ash on the rheological and filtration properties of water based...eSAT Journals
Abstract An experimental investigation was carried out to study the effect of fly ash on the rheological and filtration properties of water based drilling fluids with the objective of the development of environmentally acceptable non-damaging and inhibitive drilling fluid system to drill sensitive formations. Initially, different drilling fluids combinations were prepared using carboxy methyl cellulose (low viscosity grade), polyanionic cellulose, xanthan gum, and potassium chloride. The rheological properties as well as filtration properties of these drilling fluids were measured by API recommended methods. These drilling fluids show very good rheological behavior but poor filtration loss characteristics. When fly ash was added in these drilling fluid combinations, a nanoparticles fluid system was established which has better control on filtration properties without affecting the rheological properties and has good potential for the drilling of sensitive formations. Index Terms: Filtrate Loss Properties, Rheological Properties, Wellbore Instability, Inhibitive Drilling Fluid, Nanoparticles, Shale.
IRJET - Shrinkage Crack Study due to Lead Contamination in Bentonite ClayIRJET Journal
1. The document studies the effect of lead contamination on the shrinkage cracking of bentonite clay. Bentonite clay samples contaminated with varying percentages of lead (0-0.1%) were tested.
2. The results showed that with increasing lead concentration, the consistency limits (liquid limit and plastic limit) of the bentonite clay decreased. The shrinkage limit was not significantly affected. Hydraulic conductivity increased with increasing lead concentration.
3. Digital image processing was used to analyze the crack patterns of the contaminated bentonite clay samples. The crack intensity factor, which is the ratio of crack surface area to total surface area, increased with higher lead contamination levels.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Functionalized Ceramic Membranes for the Separation of Organics from Raw Wate...Samuel Maguire-Boyle
This patent application describes functionalized ceramic membranes for separating organics from raw water with reduced fouling. It specifically describes coating ceramic membranes, such as silicon carbide membranes, with hydrophilic functional groups to make them more hydrophilic and resistant to fouling. This functionalization process allows the membranes to have larger pores and operate at lower pressures than existing membranes, while maintaining separation performance and limiting fouling, scaling, and permeability reductions.
IRJET- Comparative Evaluation of Bentonite Soil with Ordinary Clay for Contro...IRJET Journal
The document evaluates the use of bentonite-clay mixtures as liners in landfills to control leachate movement. It analyzes the physical properties of clay mixed with 2.5%, 5%, and 7.5% bentonite by weight. The mixtures showed reduced hydraulic conductivity, increased shear strength, and decreased compressibility compared to clay alone. This makes the mixtures more effective long-term barriers against leachate. The document also examines the chemical composition of leachate from a landfill site and how it interacts with the bentonite-clay liners.
Chemical admixtures are added to concrete to modify properties in either the plastic or hardened state. There are two main types - chemical admixtures and mineral admixtures. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Plasticizers and superplasticizers disperse cement particles, allowing a reduction in water content while maintaining workability. Superplasticizers can reduce water by up to 30% compared to 15% for plasticizers. Admixtures are used to achieve desired properties, maintain quality during placement and curing, overcome issues, and reduce concrete costs.
This document discusses the effects of salt water on concrete and provides recommendations for designing concrete that will be exposed to seawater. It notes that seawater contains salts that can deteriorate concrete through processes like sulfate attack, lime leaching, alkali-aggregate expansion, and corrosion of reinforcing steel. It recommends using low permeability concrete to limit these effects, and controlling key parameters like water-cement ratio, cement type, use of air-entraining agents, and concrete cover over reinforcing steel. The document provides tables with guidelines on these parameters and recommends repair methods that involve removing deteriorated concrete, cleaning reinforcing steel, and applying a protective barrier between the concrete and salt water.
IRJET - Variation of Cumulative Water Absorption in Concrete CubesIRJET Journal
This document summarizes research on the variation of cumulative water absorption in concrete cubes. It discusses how water absorption and permeability affect the durability of concrete structures. The researchers conducted experiments with 72 concrete cubes containing different concrete mixtures to evaluate the effectiveness of cumulative water absorption. The results showed that cumulative water absorption decreases with decreasing water absorption and increases with increasing water absorption rate. Cumulative absorption also decreases with increasing aggregate content and compressive strength but increases with higher water-cement ratios and over time. The sorptivity coefficient, which indicates water penetration rate, decreases with higher compressive strength and cumulative absorption.
Water quality has a significant impact on concrete strength. Impurities like chlorides, sulfates, and dissolved solids can reduce strength if present in high concentrations. Testing the compressive strength of concrete made with local water compared to distilled water determines if the local water is suitable. While seawater reduces early strength by 10-15% and may cause corrosion of reinforcement, it can be used for unreinforced concrete if the mix is redesigned. However, seawater is prohibited for reinforced or prestressed concrete per current Indian standards due to corrosion risks.
Seth Czaplewski proposes recycling unused clay materials and broken ceramics by incorporating them into new ceramic works or converting them into biochar. Some materials that can be recycled include clay abandoned in studios, contaminated clay, excavated clay from other projects, wad and wash from ceramic production, and unwanted or broken pots. Biochar is a charcoal-like material produced by heating biomass in low-oxygen conditions that can sequester carbon in soil for thousands of years and improve soil quality and plant growth. By recycling clay wastes and converting ceramics into biochar, Czaplewski aims to both reduce ceramic waste and educate the public about sustainable practices.
NEW RAW MATERIALS FOR PAPER PULP (the book)Mostafa Ahmad
This document provides acknowledgements and thanks to various individuals who contributed to the research project. It thanks Allah, the research supervisor Prof. Dr. Mamdouh M. Nassar and other professors at Minia University in Egypt for their guidance and support of the project. It also thanks other individuals who provided assistance with laboratory work, research contacts, and information collection. The document was completed in El-Minia, Egypt in 2016 by the listed authors.
Mary Frank is a significant influence on the artist. Frank sculpts psychologically complex figurative ceramic sculptures that break new ground in construction methods and the manipulation of clay slabs. Frank's work deals with themes of birth, death, sexuality, and sensory experiences through powerful female figures.
This chapter discusses various handbuilding techniques for ceramics including pinch, coil, and slab construction. Pinch and coil construction were widely used in ancient cultures, while slab construction was more common in Mesoamerican cultures. Pinch forms can be delicate or thick, and coil construction can create almost any shape or form. Clay slabs can be used soft or stiff depending on the desired shape. The chapter provides guidelines for wedging clay, forming methods, surface effects, concentrating pressure points, and maintaining appropriate wall thickness.
Throw out best practices, double email conversion (15 minute version)A. Litsa
Watch on YouTube: http://www.youtube.com/watch?v=YdFDAjieEpw
We figured out how to increase email-campaign conversion by 146%!
Last summer my team studied post-transaction email with the goal to influence more shoppers to review recent purchases. After much trial and error and one major pivot, we learned something key to conversion: email is a mobile thing.
This eureka moment motivated the team to explore the relationship between smartphones, email campaigns, and website traffic. In this session you will
• Get compelling statistical evidence of the strong relationship between email and mobile
• Hear the story of our trial and error, and what lead to a major pivot in the study
• Learn why and how you can double email campaign conversion too
• Discover the potential impact of mobile device usage in a least two other major marketing channels
• Find out what critical oversight web-analysts make when measuring mobile traffic
Enjoy! And please tweet feedback to @a_litsa
Better slides: http://prezi.com/5ws8tsf7cxfx/mysqlhandlersocketnosql/
More info: http://bit.ly/pluk2012
We've been using HandlerSocket in our infrastructure for 2 years here at Badoo. Badoo has extensive experience running HS in production. More and more teams in our company use HandlerSocket for their projects.
We're currently using HandlerSocket as a Memcached replacement in some cases, as a search engine in some other cases and as a primary key-value storage for mobile & desktop applications. Our HS installation has more than 30 servers serving max. ~ 8000 RPS per server. I have written a custom HS client library for PHP including a couple of tricks and optimizations I'm going to show you.
I'm going to speak on:
Brief HS introduction.
What HS is and what it is not. The benefits it provides.
HS internals.
Common use cases, a detailed description of one or two use cases @ Badoo with figures.
Performance issues, speeding it up:
Sharding
HS with Percona Server
Using HS with persistent connections. Pros and cons, problems, solutions.
Tips & tricks: pipelining, lazy open_index, etc.
Useful links: HS client libraries, articles, Percona Server Handlersocket page.
This will not be an introductory talk but a summary of my practical experience including graphs, numbers and pitfalls.
BP Venezuela Indigenous Relations: Meeting the Challenge – Responsibly and S...Wayne Dunn
Wayne Dunn prepared this report to assist BP Venezuela to work more effectively with the Warao Peoples of the Orinoco Delta, where BP had recently begun exploring. The report is based on field research and detailed analysis undertaken by Wayne Dunn. It explores the current state of BP/Warao relationships and emerging challenges. It examines the current socio-economic state of the Warao, which was deplorable (not because of BP). The report set out a framework to enable BP to develop mutually beneficial and productive relationships with the Warao Peoples and also outlined a framework that would enable effective management of the relationship efforts.
Longboards range from 36 to 60 inches and have larger, softer wheels than trick boards, providing a smoother ride. They use softer bushings or springs instead of bushings to allow for easier carving. Longboards can be used for travel or transport and come in different shapes like cruisers or hybrid boards. Their trucks are designed for sharper turns. Pintail shapes are useful for lifting the front of the board when riding off curbs. Longboarding originated in Hawaii in the late 1950s as surfers sought to replicate the feeling of surfing on land, and grew as a sport in California in the 1970s.
The document outlines the typical process for designing an interactive website, including research, site mapping, wireframing, creating a mood board, designing pages in Photoshop, and coding the design into HTML and CSS. The key steps are:
1. Conducting research on the client objectives, target audience, and competitors.
2. Creating a site map to diagram the page structure and filenames.
3. Developing wireframes as a visual guide to the skeletal framework of the website.
4. Assembling a mood board to make design decisions on look and feel.
5. Designing page templates and elements in Photoshop.
6. Coding the Photoshop design into HTML
Республиканский конкурс идей «Инновационный Казахстан»АО "Самрук-Казына"
Республиканский конкурс идей «Инновационный Казахстан» стартовал 19 сентября 2012 года. Организатором конкурса является АО «Самрук-Қазына». Конкурс призван поддержать казахстанских инноваторов и помочь им в реализации своих проектов.
O documento discute a importância da gestão de canais de distribuição para o sucesso da estratégia de marketing. Apresenta como os canais de distribuição, como atacadistas, varejistas e representantes, desempenham um papel crucial na disponibilidade e exposição dos produtos para os consumidores finais. Também destaca que as empresas precisam tratar os canais como um público-chave e parceiro relevante para obter bom desempenho no mercado.
This document compares and contrasts two types of comparison essays: point by point essays and similarities and differences essays. It outlines the structure of each, including the introduction, body paragraphs, and conclusion. Point by point essays discuss topics related to both subjects in separate body paragraphs, while similarities and differences essays have body paragraphs on similarities, differences, and main differences. The document provides guidance on when each organizational structure is most appropriate based on the thesis and focus of the comparison.
65% of U.S. high school students use the internet several times a week for news and information, with 50% using mobile devices for this purpose. Social media is an effective way for newspapers to reach teen audiences where they spend their time online and on their phones. Using platforms like Facebook, Twitter, and emerging technologies teaches students digital media skills while helping publications raise awareness of their programs and showcase their work. It is important for newspapers to have a presence on social media in order to teach news literacy and online safety to the next generation.
Tek 2013 - Building Web Apps from a New Angle with AngularJSPablo Godel
AngularJS is a new JavaScript framework, backed by Google, for building powerful, complex and rich client-side web applications. We will go over the features and basics of building a web application with AngularJS and we will demonstrate how to communicate with a REST server built with PHP.
Аденома предстательной железы — это одно из наиболее распространенных заболеваний у мужчин в возрасте старше 50 лет.
По данным статистики аденома простаты регистрируется в данной возрастной группе более чем у 50% мужского населения по всему миру, а после достижения 70 лет – у 75%.
This project aims to improve primary education in 2 districts in western Jharkhand, India. It will work in 80 schools over 3 years to help children achieve grade-appropriate learning levels in language and math. Key strategies include strengthening teachers' capacity for child-friendly teaching methods, and increasing community involvement in school governance. The project will provide trained volunteers, teaching materials, and capacity building for 800 teachers and School Management Committee members. Baseline studies have begun to assess learning levels, teaching quality, and community participation to guide the project. An estimated 7,000 children will benefit from improved education opportunities.
This document discusses various types of terminology used in business, Java, and computer science. It provides examples of common buzzwords used in large corporations like "leverage" and "synergy". It also explains technical Java concepts such as lambdas, abstract syntax trees, and memory barriers. Finally, it covers computer science terms including linear regression, Markov chains, and tail call recursion. The overall message is that complex terminology can overcomplicate domains and confuse developers.
Analyzing Effects of Various Kinds of Multi-Wall Carbo Nanotubes (MWCNT) on P...crimsonpublisherscojrr
Due to the significance and unique properties of Multi-Wall Carbon Nanotubes (MWCNT), in the present investigation, the viability of these materials in the Water-Based Mud (WBM) is assessed. The impacts of various kinds of MWCNT, mud additives and surfactants on the rheological properties, water loss and drilling fluid stability of the WBM are experimentally investigated. The results have demonstrated various kinds of MWCNT, additives, and surfactants have affected the rheological properties of the WBM. Adding MWCNT and Polyethylene Glycol (PEG) alone or together decrease the terms of rheological properties performance as subsequent order CNT; CNT + PEG; PEG. Surface modified carbon nanotube (Functionalize Carbon Nano Tube [FCNT]) improves rheological properties of the WBM and increases the shale recovery. All in all, the presence of Multi-Wall Carbon Nanotubes increases the efficiency of polymers and improves the rheological properties and performance of the water base mud.
IRJET- Effect of Shale on the basis of its Particle Size, on the Rheology of ...IRJET Journal
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Determination of Effect Bentonite and Additives On Drilling FluidsIRJESJOURNAL
Abstract :- Drilling fluids Play a vital role in hole Cleaning suspension of cuttings, prevent caving, and ensure the tightness of the well wall. Moreover they also help in cooling and lubricating the drilling tool, transfer the hydraulic power and carry information about the nature of the drilled formation by raising the cuttings from the bottom to the surface, using a simple mixture of water and clays, to complex mixtures of various specific organic and inorganic products as additives. These additives improve fluid rheological properties and filtration capability, allowing bits to penetrate heterogeneous geological formations The mud used in this work is barite and bentonites at different samples to know the difference in their specific gravity, viscosity, surface tension, and pH of the samples when chemical additives are added.
This document discusses fluid loss additive in water based mud. It begins with an introduction that describes the functions and importance of drilling fluids. It then discusses the preparation and extraction of cellulose from rich gourd loofah as a potential fluid loss additive. The document presents the results of formulating different mud samples with varying concentrations of rich gourd cellulose and compares them to a standard mud containing polyanionic cellulose. It found that rich gourd cellulose performed better at reducing fluid loss and improving rheological properties compared to the standard.
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This document summarizes a paper presented at the SPE/IADC Middle East Drilling Technology Conference & Exhibition in 2005. The paper discusses the use of a unique high performance water-based mud system to address drilling challenges in the Middle East, such as shale instability, swelling clays, bit balling, and losses. It describes the system's ability to reduce pressure transmission, inhibit clays, improve cutting encapsulation, minimize differential sticking, and maximize rate of penetration, comparing its performance to conventional water-based and oil-based mud systems.
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Abstract This case study examines the formation damage that occurred i.pdfatozbazar
Abstract This case study examines the formation damage that occurred in an oil field located in
the Casanare region of Colombia. The oil field had been producing oil for several years, but the
operators noticed a significant decline in production rates. The investigation revealed that the
well was suffering from severe formation damage, which was caused by the accumulation of
drilling fluids and other contaminants in the reservoir. To address the formation damage, the
operators implemented a variety of remediation techniques, including acid stimulation, matrix
acidizing, and hydraulic fracturing. These techniques were designed to dissolve the contaminants
in the reservoir and increase the permeability of the formation, allowing oil to flow more easily
to the wellbore and to the understanding of formation damage mechanisms. The Ruba field is
one of the largest oil fields in Colombia and has been in production since the 1980 s. The oil
extracted from the Ruba field is a heavy crude oil, which requires more advanced refining
techniques to produce high-quality fuels. The Ruba field is operated by several major oil
companies, including Ecopetrol, the national oil company of Colombia. The concept of skin and
formation damage play a vital role in productivity of an oil well. The effect of formation damage
zone on the well flowing pressure was introduced to the original solution of diffusivity equation.
Formation damage reduces the well production. Skin defines as the area of reduced permeability
near the wellbore due to the invasion of drilling fluid into the reservoir rock. Classifying damage
requires a lot of work to determine correctly the main reason of it. In general, fluids can interact
with reservoir rock and cause formation damage that impedes hydrocarbon production. Tight
sandstone reservoir with well-developed natural fractures has a complex pore structure where
pores and pore throats have a wide range of diameters; formation damage in such type of
reservoir can be complicated and severe. Reservoir rock samples with a wide range of fracture
widths are tested through a several step core flood platform, where formation damage caused by
the drilling or fracturing fluid, where any unintentional fluid impedance in or out of a wellbore is
referred to as damage to formation. This general definition includes the flow restriction caused
by reduced permeability in the near wellbore region. Formation damage Description and
classification: The history of damage removal is a process that begins with the identification of
the issue. This usually involves looking through the various sources of information related to the
well, such as drilling records, completion designs, and operator experiments. The desired
purpose is to identify the causes of the formation damage and how it could be fixed. Where the
types of formation damage location of damage extent and screening of damage, and effect of
damage on well production or injection. Well development and res.
This document summarizes a field study on using a liquid curable resin system to prevent proppant and formation sand production in high water cut, heavy oil wells in Argentina. The study involved hydraulic fracturing treatments using proppant coated with a low-temperature curable epoxy resin. Field results showed that the resin coating effectively stopped proppant and formation sand from being produced back while maintaining production rates. The resin treatment provided a reliable and cost-effective alternative to sand control screens for controlling solid flowback in marginal reservoirs.
This document discusses permeability reducing admixtures (PRAs) that can be added to concrete to improve its waterproofing properties. It describes how PRAs work by reducing the size, number and connectivity of pores to limit water penetration. The main types are hydrophobic, finely divided solids, and crystalline materials. Test results show crystalline PRAs can reduce permeability by up to 70%. PRAs should be used for structures exposed to moisture or hydrostatic pressure. Dosage depends on the type but is typically 2-5% by weight. Successful projects using PRAs are mentioned.
Latest Advances in the Development of Ecological Drilling Fluids John Downs
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Variation of Sorptivity in Diverse Grades of Concrete Proportioned with Fly A...IRJET Journal
This document discusses a study on the variation of sorptivity in different grades of concrete with additions of fly ash, wood husk ash, and rice husk ash. Sorptivity testing was performed on concrete cubes of M25, M30, and M35 mixes with different cement replacements (Type 1: 100% cement; Type 2: 90% cement + 10% fly ash; Type 3: 90% cement + 10% wood husk ash; Type 4: 90% cement + 10% rice husk ash). The study found that concrete with 10% cement replaced with wood husk ash (Type 3) had the lowest sorptivity values compared to the other mixes. In general, mixes with mineral admixt
“EXPERIMENTAL STUDY ON PARTIAL REPLACEMENT OF CEMENT BY SEWAGE SLUDGE ASH AND...IRJET Journal
This document summarizes several studies on the use of sewage sludge ash (SSA) as a partial replacement for cement in concrete. Key findings include:
- SSA can replace up to 10-15% of cement without significantly reducing concrete's mechanical properties. SSA concrete showed improved strength in some studies.
- SSA modifies the pore structure of concrete, reducing absorptivity and permeability.
- Pre-treatments like drying, grinding, or calcining SSA can improve its properties as a cement replacement and affect the workability and strength of concrete.
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Foam Assisted Surfactant-Alternating-Gas Injection for Heavy Oil Recovery thr...Antonio B. Mejia Jr.
This document proposes a method for producing heavy oil through permafrost in Alaska's North Slope region. A vertical well will be drilled and completed with two deviated laterals, one for injection and one for production. Carbon dioxide injection will be used to reduce oil viscosity and interfacial tension. Special casing, cementing, and insulation techniques will maintain permafrost integrity. Foam assisted surfactant-alternating gas injection combined with artificial lift will enable heavy oil production while preserving the permafrost layer.
Analysis of Admixtures and Their Effects of Silica Fumes, Metakaolin and PFA...IJMER
This paper presents a review of the properties of fresh concrete including workability, heat
of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica
fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA).
Comparison of normal and high strength concrete in which cement has been partially supplemented
by mineral admixture has been considered. It has been concluded that mineral admixtures may be
categorized into two groups: chemically active mineral admixtures and microfiller mineral
admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete
but increase the heat of hydration and reactivity. On the other hand, micro filler mineral admixtures
increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In
general, small particle size and higher specific surface area of mineral admixture are favourable to
produce highly dense and impermeable concrete; however, they cause low workability and demand
more water which may be offset by adding effective super plasticizer.
The influence of superabsorbent polymer beads used as internal curing agent o...IRJET Journal
The document discusses using superabsorbent polymer beads as an internal curing agent to improve the compressive strength of mortar. Internal curing provides additional internal water to continue cement hydration and reduce shrinkage cracking. Superabsorbent polymers are effective internal curing agents as they can absorb large amounts of water during mixing and release it later. The study aims to assess the impact of superabsorbent polymer beads on the compressive strength of mortar cured under different conditions (sealed, unsealed, pond, mist). Prior research on using superabsorbent polymers in concrete has shown mixed results, with some studies finding reduced compressive strength and others finding similar or improved strength compared to mixes without polymers.
Damage control technology of oil-based drilling fluid for shale and tight san...eSAT Journals
Abstract In drilling fluid systems, oil-based drilling fluid have advantages of protecting reservoir and keeping borehole stability in traditional recognition, it also have advantages of high temperature resistance, salt and calcium resistance, good lubricity and low damage, these all let oil-based drilling fluid as an important mean of complex formation drilling for high temperature deep well, high angle directional well, horizontal well and so on. But oil-based drilling fluid has the following damage: drilling fluid invade into formation and cause wettability change of rock surface; oil phase enter into formation and cause the reduce of effective flow area; emulsion block formation; migration of oil-wet solid-phase particles, solid-phase particle invasion and so on would also bring many damages to formation. This study analyzed the current situation and challenge of oil-based drilling fluid, put forward solutions, and provided some references for reservoir protection of oil-based drilling fluid.
Keywords: Oil-Based Drilling Fluid, Reservoir Protection, Wettability, Oil-Phase Trapping
IRJET- A Study on Usage of Super Absorbent Polymer and Presoaked Vermiculite ...IRJET Journal
This document discusses a study on the use of super absorbent polymer (SAP) and pre-soaked vermiculite as internal curing agents in concrete. Internal curing involves introducing a curing agent into concrete that provides additional internal moisture to continue hydration and prevent self-desiccation cracking. The study aimed to evaluate how replacing cement with 0.35% SAP or sand with 5% pre-soaked vermiculite impacted the 28-day compressive, flexural, and split tensile strengths of concrete. The results indicated higher strengths when using SAP and vermiculite as internal curing agents compared to a control mix without them.
IRJET- Experimental Approach for Underwater Concrete FormulationsIRJET Journal
This document discusses experimental approaches for developing underwater concrete formulations. It begins with an introduction to underwater concreting and a literature review showing limited recent work in this area. It then outlines 15 experimental concrete mixes containing ordinary Portland cement, superplasticizers, mineral admixtures, and various natural and synthetic viscosity-enhancing admixtures. The document discusses the properties required for underwater concrete, including flowability, bleed resistance, and strength development. It also reviews methods for testing underwater concrete, including washout resistance. The goal of the experiments is to identify admixtures that provide effective washout resistance at low cost using available natural materials.
Clay Migration in Proppant during Production in Argillaceous Unconsolidated R...CrimsonPublishersAMMS
Clay Migration in Proppant during Production in Argillaceous Unconsolidated Reservoir by Weidong Zhanga*, Xuhui Guan, Maoyong Fu and Shouqiang Zhao in Aspects in Mining & Mineral Science
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https://www.productmanagementtoday.com/frs/26903918/understanding-user-needs-and-satisfying-them
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Top mailing list providers in the USA.pptxJeremyPeirce1
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How are Lilac French Bulldogs Beauty Charming the World and Capturing Hearts....Lacey Max
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years in a row, the Labrador Retriever has dropped to second place
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How to Implement a Strategy: Transform Your Strategy with BSC Designer's Comp...Aleksey Savkin
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1. Copyright 2008, AADE
This paper was prepared for presentation at the 2008 AADE Fluids Conference and Exhibition held at the Wyndam Greenspoint Hotel, Houston, Texas, April 8-9, 2008. This conference was sponsored by
the Houston Chapter of the American Association of Drilling Engineers. The information presented in this paper does not reflect any position, claim or endorsement made or implied by the American
Association of Drilling Engineers, their officers or members. Questions concerning the content of this paper should be directed to the individuals listed as authors of this work.
Abstract
Water-based drilling fluids have evolved as new chemical
solutions have been developed to reduce or significantly retard
their interaction with claystones and shales. Issues related to
cuttings agglomeration and accretion can lead to increased
non-productive time which can make water-based drilling
fluids less attractive as alternatives to oil-based drilling fluids.
Cuttings agglomeration and accretion are highly dependant
on the morphology of the sedimentary rock formations being
drilled. Experimental results are presented herein on a number
of outcrop shales to show the effect that cuttings type and
morphology has on agglomeration. Possible mechanisms for
agglomeration, linked to the kinetic hydration and plastic
deformation, of cuttings when exposed to water-based drilling
fluids are discussed.
High-performance water-based drilling fluids typically
contain specific additives to enhance their lubricity and shale
inhibitive properties. Adsorption of certain polymers can lead
to an increase in the surface stickiness of cuttings and
therefore an increased agglomeration potential. Experimental
results from testing various encapsulating polymer chemistries
are presented, showing that polymers with more hydrophobic
moieties are beneficial.
Experimental results will also be presented showing the
benefits of certain film-forming additives to reduce the onset
of cuttings agglomeration and the negative effects that can
occur with certain lubricants based on vegetable oils and fatty
acid derivatives. The authors show that careful selection of
drilling fluid components can help to reduce the potential for
cuttings agglomeration and thus enhance the performance of
water-based drilling fluids.
Introduction
The use of high-performance water-based drilling fluids or
“muds” (HPWBM) is becoming more widespread as many
operators seek alternative, environmentally acceptable, drilling
fluid solutions for technically demanding drilling operations.
Provided that all of the HPWBM components satisfy local
environmental regulations, in most operational areas there are
no limitations on the amount of HPWBM which can be
discharged.
With the use of oil-based or synthetic-based drilling
fluids (OBM/SBM), there is often an associated cost for
cuttings remediation, waste-stream processing and compliance
testing, all of which must be considered in the economics of
the wellbore construction process. The higher operational
costs associated with the use of OBM/SBM can sometimes be
offset by higher rates of penetration (ROP) and fewer
operational problems as compared with conventional water-
based drilling fluids (WBM). With the introduction of new
chemistry which has been deployed in the new generation of
HPWBM, wellbore instability problems have been
significantly reduced. However, problems associated with bit
balling, agglomeration and accretion of drilled cuttings may
still occur, all of which may have the potential to lead to
increased non-productive time (NPT) during the drilling
process. This can severely detract from the overall
performance of the HPWBM.
The phenomena of accretion and agglomeration are still
poorly understood, due to a lack of field data, variable drilling
practices and changes in formation lithology. In this paper the
mechanical deformation of a number of clays is studied to see
if a link can be established between either the clay mineral
composition or clay plasticity, and the onset of the accretion
process.
From close examination of changes in drilling fluid
chemistry, exposure time, and applied mechanical load, it was
also hoped to make reasonable recommendations on measures
which could be applied to minimize cuttings accretion and
agglomeration problems during the drilling operation. If the
potential for cuttings accretion and agglomeration problems
could be mitigated by implementation of simple chemical
solutions, the economics of using HPWBM would be further
improved by reducing the risk of drilling-fluids-related NPT
occurring.
Background
Accretion and Review of Proposed Mechanisms
The first instances of cuttings accretion and accretion-
related problems were seen to coincide with the introduction
of more inhibitive WBM, typically containing high
concentrations of organic molecules such as polyglycerols/
polysaccharides and poly-anionic species (e.g. polyphosphates
and silicates). The latter are thought to form a barrier at the
shale surface to reduce water migration into shales. Early
theories based on clay plasticity were proposed to explain the
accretion phenomenon.1,2
These theories are based on the
concept of a reduced water penetration into drilled cuttings,
slowing down the rate of hydration so that the cuttings remain
AADE-08-DF-HO-10
Agglomeration and Accretion of Drill Cuttings in Water-Based Fluids
S. Cliffe, M-I SWACO and S. Young, M-I SWACO
2. 2 S. Cliffe and S. Young AADE-08-DF-HO-10
in a plastic state over a longer period of time. The extended
plasticity state of the clay is thought to allow cuttings to
become molded onto the BHA components and plastered onto
the near-wellbore wall.
With a less inhibitive mud, such as a potassium chloride/
polymer fluid, these cuttings would normally hydrate more
quickly and tend to be less sticky as they continue to adsorb
water, resulting in the loss of cohesion in the clay matrix
which is more easily removed. However, a lower level of
chemical inhibition in WBM can often cause bit balling and
wellbore instability problems.
The conditions which should be met for clay
agglomeration or accretion to occur are suggested as follows:
(a) The clay is in a plastic state at the equilibrium moisture
content when in contact with the drilling fluid. The plastic
behavior allows the clay structure to be easily deformed.
(b) The surface of the clay particle is sticky enough to
form a bond to other surfaces with which it makes contact.
(c) The surfaces of cuttings must be pushed together
(sheared) with sufficient force to deform the clay and create a
bond. The effect of mechanical deformation on the phase
behavior of clay particles is a consideration which has been
overlooked in the past.
The current range of HPWBM contains additives to
prevent transfer of water to the formation and reduce clay
hydration. The vast majority of shales and claystones drilled
contain expandable clay minerals which will have a strong
tendency to swell when exposed to a continuous phase
containing water. Low-molecular-weight amines, polyamines
and polyether-amines are some examples of the chemistries
that can be used to reduce interstitial clay swelling.
An encapsulating polymer is also often used in conjunction
with such primary shale swelling inhibitors. The encap-
sulating polymer adsorbs onto drilled cuttings and onto the
near-wellbore wall to minimize dispersion and wellbore
erosion.
In addition, increasingly, additives are being recommended
to reduce the potential for bit balling, cutting agglomeration
and accretion problems. There seems to be a consensus in the
industry that these additives function by coating steel and
cuttings surfaces to form a hydrophobic film which reduces
the adhesion of hydrated clays to the BHA and also helps to
prevent cuttings agglomeration.3,4,5,6,7,8,9
Other innovative approaches to prevent bit balling are
described in the literature that involve applying a low-friction
polymer coating to the bit10
or from applying a negative
potential which generates an electro-osmotic effect.11
Although engineering solutions to bit balling and accretion are
very interesting, they are outside the scope of this paper.
Clay Structure and Reactivity
The clay minerals which are commonly found in shales
and claystones can broadly be grouped into kaolinite, smectite,
mica, and chlorite. The crystalline structures of these clay
minerals and mixed layer structures are described extensively
in the literature.12
In simple terms, clays can be categorized
depending on the way that tetrahedral and octahedral sheets
are packaged into layers and on the composition of the
tetrahedral and octahedral sheets. Changes in the composition
of the layers results in the layers having a net negative charge.
Clay behavior is largely dependent on the interaction
between the basic structural framework and the pore fluid,
with the interactions being mainly chemical or electro-
chemical in nature. This is believed to arise from the
unsatisfied electrical charge of clay platelets, which affects the
structure and behavior of water in the vicinity of the clay
platelet. The residual repulsion between clay platelets, due to
hydration of the clay surfaces and sterical interferences
between hydrated ions and water molecules, gives rise to a net
swelling pressure,2
which will vary greatly between differing
clay minerals. The type and concentrations of clay minerals
present will determine how chemical inhibitors affect the
swelling response of bulk clays on contact with water.
Atterberg Limits
The Atterberg limits of a soil or clay are the liquid limit
(LL), plastic limit (PL), and plastic index and are fully defined
in the published literature.13
Various researchers have
attempted to correlate the Atterberg limits with clay mineral
composition, cation exchange capacity and swelling
characteristics.
The liquid limit is the moisture content, expressed as a
percentage by weight of the oven-dry soil, at which the soil
will just begin to flow when jarred slightly.
The plastic limit is the lowest moisture content,
expressed as a percentage by weight of the oven-dry soil, at
which the soil can be rolled into ⅛-in. diameter threads
without breaking into pieces. Soil which cannot be rolled into
threads at any moisture content is considered non-plastic.
The plastic index is the difference between the liquid
limit and the plastic limit. It is the range of moisture content
through which a soil is plastic. When the plastic limit is equal
to or greater than the liquid limit, the plastic index is recorded
as zero.
White14
determined the Atterberg Limits of four
homoionic montmorillonites and concluded that the structure
of the clay minerals seems to be the most important factor in
determining the properties of clay-water systems. The cation
exerts a secondary influence by which it can only act to alter
the properties established by the structure of the clay mineral.
Structure is probably determined by the location of the
substitutions within the lattice and by the distribution of the
substitutions.
Extensive studies on montmorillonitic and kaolinitic soils
have been carried out by Sridharan et al.15,16,17
who concluded
that diffuse double-layer repulsion has a dominant influence
for montmorillonitic clay, with the liquid limit increasing with
the increasing hydrated radius of the adsorbed cation,. For
kaolinitic clays the electrical attractive forces and particle
orientation in the fabric play a prominent role. Kaolinite soils
with a greater degree of flocculation will have larger void
spaces and exhibit higher liquid-limit values, whereas soils
with a lesser degree of particle flocculation will have
3. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 3
relatively smaller void spaces, and consequently, exhibit lower
liquid-limit values. This means that the mechanisms
controlling clay behavior can be entirely different depending
on whether the primary mineral is kaolinite or
montmorillonite. It follows that the chemical effects of
drilling fluid additives should be carefully selected if the
mechanical properties of clays are to be better controlled.
In more recent work Sridharan et al. concluded that both
liquid limit and plastic limit are primarily a function of percent
clay fraction, clay mineral type and the type of associated
cations present.18
The results of this work are summarized in
Tables 1 and 2. The ratio of PL/LL was seen to increase in the
following series:
Na-bentonite < Illite < Kaolinite < Halloysite
A relationship was also proposed which could be used to
classify soils as kaolinitic or montmorillonitic by examining
the PL/LL ratio. Clays with a higher montmorillonite fraction
and lower kaolinite fraction tend to have a lower PL/LL ratio.
A correlation between the valency and size of the
adsorbed cation and the index properties of bentonite clays
was seen. The PL/LL ratio was also seen to increase with
increasing valency and as hydrated ionic radius increases,
according to the series below.
Na+
< K+
<Ca2+
<Mg2+
<Fe3+
<Al3+
In addition, when sand or silt is introduced as a diluent, a
reduction in the magnitude of the plastic and liquid limits
values was observed, but the PL/LL ratio was seen to remain
constant.
These concepts described above, coupled with X-ray
powder diffraction (XRPD) studies and determination of
Atterberg limits, are used later on in this paper to propose an
explanation of the experimental results obtained at the
macroscopic scale.
Characterization of Outcrop Clay Samples
Description
Preserved outcrop shale samples were used in the
experimental work described in this paper. The clays were
kept in a controlled environment to preserve the water content
as closely to the natural state as possible. The clays selected
for the study have a broad range of reactivity from highly
dispersive (Arne clay) to moderate/highly swelling
(Oxford/Green-Lillebaelt clays).
Oxford Clay is a swelling and moderately dispersive shale
of Jurassic origin.
London Clay is a plastic, swelling and very dispersible
Tertiary clay.
Foss Eikeland clay is a dispersive clay from an outcrop in
Norway.
Arne Clay is described as a ball clay with high kaolinite
content and is extremely dispersive in contact with water.
Green-(Lillebael)t Clay is fine-grained swelling clay from
an outcrop in Denmark.
London, Oxford and Arne clays are all sourced from
outcrops in southern England.
Cation Exchange Capacity (CEC)
The CEC of each outcrop shale was determined by the
standard API Methylene Blue titration method. Results are
given in Table 3.
X-ray Powder Diffraction (XRPD) Analysis
The outcrop clays described above were submitted for
analysis by X-ray powder diffraction.
The bulk sample was wet ground and spray dried to
produce a random powder to which 20 wt% Corundum
(crystalline aluminum oxide) was added to act as an internal
standard for quantitative phase analysis (QPA). XRPD
patterns were recorded from 2–75°2θ using Cobalt Kα
radiation. QPA was conducted by a reference intensity ratio
(RIR) method.
Clay fractions of less than 2 μm were obtained by timed
sedimentation, prepared as oriented mounts using the filter
peel transfer technique and scanned from 2–45°2θ in the air-
dried state, after glycolation, and after heating to 300°C for
one hour. Clay minerals identified were quantified using a
mineral intensity factor approach based on calculated XRPD
patterns. The XRPD patterns, with the main phases identified
by reference to patterns from the International Centre for
Diffraction Database (ICDD), are provided for reference.
The outcrop clay samples vary in mineralogy. They are all
dominated by dioctahedral clay minerals (illite, illite-smectite
and kaolinite) with smaller amounts of quartz, feldspars,
carbonates, pyrite, anatase, chlorite and anhydrite. The
Lillebaelt clay sample had a higher calcite content than the
other samples.
The less than 2-μm clay fractions show a variable
mineralogy, dominated by illite-smectite and illite in most
cases, with subordinate kaolinite and chlorite. The Arne clay
sample contains a significantly higher kaolinite content than
the other clay samples. The mixed-layer illite-smectite varies
in individual clay samples. The expandability of this material
in the London clay and Green(Lillebaelt) clay is high (80 –
90%) but moderate to low in the other three clays (30 – 50%).
A complete mineral breakdown is summarized in Tables 4
and 5.
Plastic and Liquid Limits
Each clay sample was allowed to air dry for a period of 72
hr and was then ground to a fine powder. The residue
remaining on a 425-µm sieve was discarded. The clay powder
fraction of less than 425 micron was used to determine plastic
and liquid limits, according to the standard method (ASTM
D4318).
Liquid limits were measured using the Casagrande
apparatus13
. The number of drops (revolutions) which was
required for a groove cut in the clay paste to close by a length
of 13 mm was measured. After each test, and further addition
of water, a small amount of sample was dried to constant
weight and the percent water content calculated based on the
dry weight of the sample. A plot of the number of drops (x-
axis) versus water content (y-axis) was then constructed. The
4. 4 S. Cliffe and S. Young AADE-08-DF-HO-10
LL (y-axis) was taken from the straight-line plot
corresponding to 25 drops (x-axis).
Plastic limits were determined by adding water to the clay
sample, shaping it into an ellipsoidal mass and rolling it into a
thread between the fingers and a glass plate. The PL was
considered to have been reached at the point at which a 3-mm
thread could be rolled out without crumbling or sticking to the
glass plate. The recovered threads were then dried to constant
weight. The PL is calculated as the percent water content of
the clay threads based on dry weight of the sample.
LL and PL results are summarized in Table 6.
The native water contents were also measured, expressed
as percentage by weight water, based on the wet state. Results
are summarized in Table 7.
Accretion Study
Rolling Bar Test Method
The mild steel bar, used in each test, was first cleaned to
remove surface rust and any chemical deposits from previous
tests. The bar was subjected to a rigorous cleaning cycle that
included a detergent wash, treatment with 200-grit wet
abrasive paper and rinsing with clean water. The surface of
the bar was then dried and given a further cleaning with
acetone to remove any residual deposits of oil/grease. Each
bar was placed centrally in the test cell, and the cell was half
filled with test fluid. The generic formulation of the 12.5-
lbm/gal HPWBM test fluid used is given in Table 8.
A 50-g sample of sized cuttings with a narrow particle-size
distribution was added to each and evenly distributed around
the central bar. Gentle agitation was then applied with a
spatula to ensure an even distribution of the solids in the fluid.
The cell was then topped up with additional test fluid to the
rim of the cell and sealed. The cell was inverted 3–4 times to
minimize the chances of cuttings sticking to the bottom of the
cell; the cell was then transferred to a rolling oven.
After rolling the cell for a defined time interval (t) at room
temperature, the bar was removed and quickly washed with a
gentle stream of tap water. The bar was then rolled on an
adsorbent paper towel to remove excess surface fluid. The
accreted solids were then scraped off, weighed (w1), dried to
constant weight at 105°C and then reweighed (w2).
Accretion is calculated from the weight of clay solids
adhering after time (t), expressed as a % of the dry clay
fraction (corrected from the initial, native, water content of the
unexposed cuttings sample, Mi).
%A = w2 (Eq. 1)
[(100-Mi)/100] x50
The moisture content (%M) of any agglomerated solids is
also measured to determine the degree of hydration of the
agglomerated material.
%M = w2 - w1 x100 (Eq. 2)
w1
To determine the rate of cuttings agglomeration and
accretion onto the steel bar, accretion tests were run at
increasing time intervals, with a separate test for each time
interval.
The standard accretion test used throughout the
experimental study described in this paper was based on a
solid steel bar (SSB) of dimensions: 150-mm length, 23.7-mm
diameter and 527-g weight. The diameter of the cell used was
63 mm. A picture of the SSB and cell configuration is shown
in Figure 1. An alternative methodology, using a hollow steel
tube (HST), was used to determine the effect of reduced
mechanical load on the kinetics of accretion, the findings of
which will be discussed later in the paper. This configuration
is shown in Figure 2.
Effect of Shale Type on Accretion
The standard outcrop shale samples were all sized into
discrete cuttings, with a particle-size distribution of 4.8 to 6.3
mm. The amount of clay solids adhering to a SSB (in the
standard accretion method) was measured at increasing time
intervals. The water contents of the accreted solids were also
measured. Figures 3 to 7 show the appearance and magnitude
of accreted material, and show that cuttings first undergo a
deformation process before forming a more uniform accreted
layer. The time dependence of the accretion process can be
seen from the data presented as Figure 8, with accretion
maxima occurring between 20 – 30 min. It is particularly
noticeable that Arne clay had a much broader accretion profile
than the other outcrop shales studied, and that there is much
greater scatter in the data.
The initial rates of solids buildup can be better seen from
the data presented as Figure 9. Green (Lillebaelt) and Oxford
clays appear to need a longer initiation time for the
deformation and accretion process to occur.
The data presented in Figure 10 shows the relationship
between percent water content of accreted solids and exposure
time. There appears to be a very rapid uptake of water by the
outcrop shale cuttings after a short exposure time (5 – 10 min).
Cuttings still continue to hydrate with increasing exposure
time, albeit at a slower rate. The data presented in both
Figures 10 and 11 shows a wide variation in the hydration
state of accreted solids, and this was seen to be very dependent
on the outcrop clay type. Figure 11 shows percent water
contents for accreted solids, where %A is greater than 50%,
and may also suggest that the width of the hydration envelope
is indicative of the time scale where there is a probability of
accretion.
Effect of Shale Composition on Accretion
The kaolinite, illite and illite-smectite mineral contents
present in the bulk shale sample can be calculated, based on
the assumption that the <2-μm clay fraction is representative
of the bulk clay fraction. These calculated clay fractions are
summarized in Table 9. Accretion figures and associated
water contents are also summarized in Tables 10 and 11 at
selected time intervals.
5. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 5
If the water content of accreted solids recovered after
specific exposure times are plotted against the calculated bulk
percent mineral fractions, a very good correlation is seen in
the data with illite and illite-smectite mineral fractions,
whereas the correlation with the kaolinite mineral fraction is
much weaker (Figures 12–14).
Analysis of the accretion data is more difficult. Generally,
there is less of a correlation between accretion and percent
mineral fraction at shorter time intervals (5 min). A stronger
correlation exists after a 10-min exposure period. With
increasing exposure time, the correlation between illite and
illite-smectite percent mineral fractions is seen to deteriorate.
Conversely, the correlation of accretion with kaolinite percent
mineral fraction is seen to markedly improve over a 60-min
time frame. This type of behavior might be expected for
complex shales which contain component parts of different
reactivity (Figures 15 – 17).
Effect of Atterberg Limits on Accretion
Contrary to the findings of Sridharan et al.,18
a strong trend
was not observed between the PL/LL ratio and percent clay
mineral fraction or accretion, based on the limited data set
available. However, a fair correlation was observed between
PL and accretion. A similar correlation was also observed
between PL and the water content of accreted solids (Figures
18 – 21).
Effect of Initial Water Content on Accretion
A sample of Oxford clay cuttings with a particle-size
distribution of 2.4 – 4.8 mm was allowed to air dry for a
period of 72 hr. The amount of clay solids adhering to a SSB
(in the standard accretion method) was measured at increasing
time intervals, and compared to results from parallel tests
conducted on a sample of cuttings of similar size distribution
preserved at native moisture content. The initial water content
of the dried sample was measured at 2.6% compared to 20.6%
in the preserved sample. Accretion and water content for the
two clay samples are shown in Figures 22 and 23. The results
show a reduced tendency for cuttings to accrete if they have
intrinsically lower water content, even though the hydration
process of accreted solids is fairly rapid. The accretion curves
eventually coalesce, but accreted solids are still significantly
less hydrated, arising from the cuttings with lower initial water
content.
Effect of Cuttings Size on Accretion
Various sized fractions of Oxford clay cuttings were
prepared. The amount of clay solids adhering to a SSB (in the
standard accretion method) was measured at increasing time
intervals. Results are shown in Figure 24. It can be seen that
with increasing cuttings size there is a general reduction in the
levels of accretion observed, particularly after shorter
exposure times. Looking at the data in a different way (Figure
25), it can be seen that in general an increase in cuttings size
reduces the rate of accretion, with the accretion maxima
requiring longer times to develop.
The lower level of accretion observed from Oxford clay
cuttings with the smallest particle-size distribution, in this case
less than 2 mm, is attributed to more rapid disintegration of
these cuttings due to their higher surface area. This is another
effect that needs to be taken into consideration.
Effect of Mechanical Force on Accretion
The effect of mechanical force on the deformation of
cuttings and on the kinetics of accretion was studied by
substituting the SSB with a hollow steel tube (HST), of
dimensions: 120-mm length, 35-mm diameter, 138-g weight.
Accretion profiles are shown in Figures 26 and 27 for both the
SSB and HST methods, using 4.7- to 6.3-mm sized Oxford
clay and Arne clay cuttings, The onset of accretion appears to
be significantly delayed with the lighter HST compared to the
SSB, which results in a displacement of the accretion profiles
to longer times. In addition, the accretion profiles occur over
significantly wider time periods with the HST. In separate
cuttings dispersion tests, using identical drilling fluid
components to the ones used in this study, there were no
visible signs of cuttings agglomeration even with a much
longer exposure time and heating (16 hr at 150°F). These
results indicate that some mechanical deformation of cuttings
must occur before accretion and agglomeration can take place.
Effect of Drilling Fluid Additives
In a supplementary study, the effects of varying chemistry
and concentration of specific drilling fluid components on
accretion were investigated. This initial investigation has
already led to the development of some novel chemical
solutions to reduce cuttings accretion and agglomeration.
Figures 28 and 29 show the benefits of two new, novel
encapsulating polymers (Polymer C and Polymer D) compared
to Polymer A. The latter is based on conventional
polyacrylamide encapsulator chemistry, which has been
widely used in WBM.
The effect of a number of anticrete additives of varying
composition and at varying concentrations are shown in
Figures 30 and 31. It is apparent from the data presented that
the effective concentration of the anticrete must be considered
if accretion is to be sufficiently controlled. New anticrete
formulations (Anticrete #2) have been developed which form
stronger interfacial films on the surfaces of cuttings and are
subsequently more effective at lower concentrations.
During the course of the investigation into the composition
of anticretes it was observed that certain fatty acid and fatty
ester-based lubricants can actually increase cuttings
agglomeration and accretion problems. Figure 32 summarizes
some of the lubricant investigation data, showing that the
addition of certain lubricants can have a detrimental effect on
accretion.
Conclusions
Both from investigations into accretion incidents from the
field and from the extensive laboratory studies carried out,
there is significant evidence to indicate that shales that contain
a higher percentage of illite and kaolinite mineral fractions
6. 6 S. Cliffe and S. Young AADE-08-DF-HO-10
will be more susceptible to accretion when exposed to
HPWBM.
Accreted solids tend to become more hydrated when
composed of clays containing higher percentages of illite-
smectite mineral fractions. In contrast, lower levels of
hydration are observed with higher percentage mineral
fractions of illite and kaolinite.
A strong trend was not observed between PL/LL ratio and
either percent clay mineral fraction or percent accretion, based
on the limited data set gathered in these experiments.
However, a good correlation was observed between PL and
accretion. A similar correlation was also observed between
PL and the water content of accreted solids. From the
experimental data it is believed that use of Atterberg limits
could be helpful in predicting which shale types have the
greatest accretion tendency. This would, however, require
reliable samples of substantially unaltered clays.
It was also experimentally shown that the accretion process
can be substantially reduced by lowering the native water
content of the cuttings or by generating a larger particle-size
distribution of cuttings. Greater drilling performance
advantages can thus be taken by better matching bit type to
both formation type and selection of the HPWBM
composition.
Some mechanical degradation of cuttings is necessary for
the accretion process to occur, thus taking steps to optimize
ROP, and cutting transportation can have benefits in reducing
accretion tendency.
The careful selection of drilling fluid components, trying
to better match these to the anticipated shale properties, can
certainly reduce accretion tendency. Continuing with this type
of work and using the results to assist in the design of new
encapsulating polymers and anticrete additives will give
benefits in reduced accretion potential and improved
performance from the HPWBM.
Acknowledgments
XRPD analysis and data interpretation was carried out by
Macaulay Analytical Services, Macaulay Enterprises Limited,
Aberdeen, UK.
The authors would like to thank M-I SWACO for
sponsoring this work and for permission to present this paper.
Nomenclature
HPWBM = High-performance water-based drilling fluid
CEC = Cationic exchange capacity
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7. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 7
Table 1 – PL/LL Ratios for Various Clay Minerals
(Sridharan et al.18
)
Clay Mineral Ratio of PL/LL
Na-Bentonite 0.07 – 0.26
Illite 0.31 – 0.51
Kaolinite 0.36 – 0.70
Attapulgite 0.54
Halloysite 0.88
Table 2 – Influence of Valency and Size of Adsorbed
Cations on the Index Properties of Bentonites
(Sridharan et al.18
)
Bentonite-
homoionized
PL LL
Ratio of
PL/LL
Li+
, Lithium 49.1 675 0.073
Na+
, Sodium 19.2 495 0.099
NH4+
, Ammonium 55.8 223 0.250
K+
, Potassium 57.8 233 0.248
Ca2+
, Calcium 40.6 125 0.325
Mg2+
, Magnesium 49.9 129 0.387
Ba2+
, Barium 45.8 108 0.424
Al3+
, Aluminium 60.5 108 0.560
Fe3+
, Iron 63.5 120 0.524
Table 3 – CEC of Outcrop Clays
Sample ID CEC (meq/100 g)
Arne Clay 7 - 16
Foss Eikeland Clay 14
London Clay 20
Green Clay(Lillebaelt) 41
Oxford Clay 22
Table 4 – XRPD Analysis on Bulk Clay Fraction
Sample ID Quartz Plagioclase K-fspar Calcite Dolomite Siderite
Arne Clay 14.8 1.4 1.5 0.9 0 0.3
Foss
Eikeland
Clay 22.1 18.1 11.2 2.6 1 0.5
London Clay 24.4 1.9 4.3 1.4 1.6 0.7
Green Clay
(Lillebaelt ) 3.6 1.2 2.6 21.8 0 0
Oxford Clay 18.9 1.5 3 8 0.5 1
Sample ID Pyrite Anatase Anhydrite Kaolinite
Diocta-
hedral
Clays
Triocta-
hedral
Clays
Arne Clay 0 0.47 0.77 33.86 44.49 0
Foss
Eikeland
Clay 1.4 0 0 1.38 35.4 5
London Clay 1.2 0.19 0.8 8.96 47.3 3.8
Green Clay
(Lillebaelt) 0 0 0 8 67.6 0
Oxford Clay 2.9 0.4 0.3 12.8 47.3 3.8
Table 5 – Relative Percentage of Clay Minerals in the
<2-mm Clay Size Fraction
Sample ID Chlorite Kaolinite Illite
Illite-
Smectite
Arne Clay 1 35 36 28
Foss Eikeland Clay 3 10 41 47
London Clay 1 9 17 74
Green Clay (Lillebaelt) 1 5 3 91
Oxford Clay 2 8 19 72
Table 6 – Atterberg Limits Measured on Outcrop Clays
Sample ID PL LL PI
Ratio of
PL/LL
Arne Clay 34.6 69.4 34.8 0.50
Foss Eikeland Clay 30.1 81.2 51.1 0.37
London Clay 34.6 70.8 36.2 0.49
Green Clay (Lillebaelt) 56.9 273 216.1 0.21
Oxford Clay 36.1 70.9 34.8 0.51
Table 7 – Percentage Water Content of Outcrop Clays
(Native State and at the Atterberg Limit Values)
Sample ID
% water at
native
state
% water at
plastic
state
% water at
liquid state
Arne Clay 3.4 25.7 40.9
Foss Eikeland Clay 17.0 23.1 44.7
London Clay 20.5 25.7 41.4
Green Clay (Lillebaelt) 26.5 36.3 73.2
Oxford Clay 20.5 26.5 41.5
Table 8 – Generic HPWBM formulation
Table 8 – Generic HPWBM Formulation
Product Concentration (g)
Freshwater 265.1
KCl 14
NaCl 14
Shale hydration inhibitor 10.8
Xanthan gum 0.7
Polyanionic Cellulose LV 1.1
Modified starch 3.2
Encapsulating polymer 2.1
Barite 214.1
Table 9 - Relative Percent Clay Fraction in Bulk Sample
Sample ID
Arne
Clay
Foss
Eikeland
Clay
London
Clay
Green
Clay
(Lillebaelt)
Oxford
Clay
Kaolinite 33.9 1.4 9.0 8.0 12.8
Illite 24.6 18.2 9.4 2.1 10.4
Illite-
Smectite 19.2 20.9 41.1 64.8 39.6
8. 8 S. Cliffe and S. Young AADE-08-DF-HO-10
Table 10 – Percentage Water Content of Accreted
Solids vs. Time (SSB Test Method)
% H2O
Time
(min) Arne
Clay
Foss
Eikeland
Clay
London
Clay
Green
Clay-
Lillebaelt
Oxford
clay
5 25.4 25.8 30.7 35 31.1
10 26.3 27.4 32.8 36.8 31.3
30 27.2 28.2 33.5 37.6 33.2
60 27.6 29.4 34.5 37.7 35.1
Table 11 – Percentage Accreted Solids vs. Time
(SSB Test Method)
% Accretion
Time
(min) Arne
Clay
Foss
Eikeland
Clay
London
Clay
Green
Clay-
Lillebaelt
Oxford
Clay
5 73.4 76.2 75.1 20.3 47.2
10 110.3 101.8 89.1 72.7 92
30 111.1 101.6 74.2 87.3 95.8
60 109.4 2.0 51.5 38.4 50.2
Figure 1 – Accretion Test Cell – Solid Steel Bar (SSB).
Figure 2 – Accretion Test Cell-Hollow Steel Tube (HST)
Figure 3 – Accretion profiles for Arne Clay (5-, 10-, 20-, 40-, 60-, and
80-min time intervals).
Figure 4 – Accretion profiles for Foss Eikeland Clay (5-, 10-, 20-, 40-,
and 60-min time intervals).
Figure 5 – Accretion profiles for Green-Lillebaelt Clay (5-, 10-, 20-,
40-, 60-, and 80-min time intervals).
9. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 9
Figure 6 – Accretion profiles for London Clay (5-, 10-, 20-, 40-, 60-,
and 80-min time intervals).
Figure 7 – Accretion profiles for Oxford Clay (5, 10, 20, 40, 60 and 80
minute time intervals).
0
20
40
60
80
100
120
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min)
%Accretion
Oxford clay
Green clay
Arne clay
Foss Eikeland
London clay
Figure 8 – Effect of shale type on accretion-time profiles.
0
10
20
30
40
50
60
70
80
90
100
Green clay Oxford clay Arne clay Foss
Eikeland
clay
London
clay
%Accretion-5min
Accretion:
short-time
compaction
Figure 9 – Effect of shale type on the initial onset of accretion.
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min)
%H2O
Oxford clay
Green clay
Arne clay
Foss Eikeland
London clay
Figure 10 – Variation in the percent water content of accreted solids
vs. time.
0
20
40
60
80
100
120
20 22 24 26 28 30 32 34 36 38 40
% H2O
%Accretion
Oxford clay
Green clay
Arne clay
Foss Eikeland
London clay
Figure 11 – Hydration curves for accreted solids, where %A > 50%.
10. 10 S. Cliffe and S. Young AADE-08-DF-HO-10
R2
= 0.8232
20
22
24
26
28
30
32
34
36
38
40
0 5 10 15 20 25 30 35
% Kaolinite
%H2O
%M- 5 min
Figure 12 – Effect of percent kaolinite fraction on water content of
accreted solids.
R2
= 0.9407
20
22
24
26
28
30
32
34
36
38
40
0 5 10 15 20 25 30
% Illite
%H2O
%M- 5 min
Figure 13 – Effect of percent illite fraction on water content of
accreted solids.
R2
= 0.9766
20
22
24
26
28
30
32
34
36
38
40
15 20 25 30 35 40 45 50 55 60 65 70
% Illite-Smectite
%H2O
%M- 5 min
Figure 14 – Effect of percent illite-smectite fraction on water content
of accreted solids.
R2
= 0.7972
R2
= 0.2699
0
10
20
30
40
50
60
70
80
90
100
110
120
0 5 10 15 20 25 30 35
% Kaolinite
%Accretion
%A -5 min
%A -10 min
Figure 15 – Effect of percent kaolinite fraction on accretion (t=5, 10
min).
R2
= 0.9715
R2
= 0.5885
0
10
20
30
40
50
60
70
80
90
100
110
120
0 5 10 15 20 25 30 35
% Illite
%Accretion
%A- 5 min
%A- 10 min
Figure 16 – Effect of percent illite fraction on accretion (t=5, 10 min).
R2
= 0.7515
R2
= 0.9655
0
10
20
30
40
50
60
70
80
90
100
110
120
15 20 25 30 35 40 45 50 55 60 65 70
% Illite-Smectite
%Accretion
%A- 5 min
%A- 10 min
Figure 17 – Effect of percent illite-smectite fraction on accretion
(t=5, 10 min).
11. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 11
R
2
= 0.8405
0
10
20
30
40
50
60
70
80
90
100
20 25 30 35 40 45 50 55 60
PL
%Accretion-5min
Figure 18 – Effect of PL on accretion (t=5 min).
R
2
= 0.6781
20
22
24
26
28
30
32
34
36
38
40
20 25 30 35 40 45 50 55 60
PL
%H2O-5min
Figure 19 – Effect of PL on percent water content of accreted solids
(t=5 min).
R
2
= 0.6899
0
10
20
30
40
50
60
70
80
90
100
110
120
20 25 30 35 40 45 50 55 60
PL
%Accretion-10min
Figure 20 – Effect of PL on accretion (t=10 min).
R
2
= 0.679
20
22
24
26
28
30
32
34
36
38
40
20 25 30 35 40 45 50 55 60
PL
%H2O-10min
Figure 21 – Effect of PL on percent water content of accreted solids
(t=10 min).
0
10
20
30
40
50
60
70
80
90
100
110
120
0 10 20 30 40 50 60 70
Time (min)
%Accretion
Oxford
clay-
Low
initial
%water
content
Oxford
clay-
High
initial
%water
content
Figure 22 – Effect of initial water content on accretion-time profile.
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70
Time (min)
%H2O
Oxford
clay-
Low
initial
%water
content
Oxford
clay-
High
initial
%water
content
Figure 23 – Effect of initial water content on hydration of accreted
solids vs. time.
12. 12 S. Cliffe and S. Young AADE-08-DF-HO-10
0
20
40
60
80
100
120
0 10 20 30 40 50 60
Time (min)
%Accretion
1.6mm
3.6mm
5.5mm
9.6mm
Figure 24 – Effect of cuttings size (Oxford clay) on accretion-time
profile.
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14
Cuttings size (mm)
%Accretion
5 min
30 min
60 min
Figure 25 – Effect of cuttings size (Oxford Clay) on accretion
maxima.
0
10
20
30
40
50
60
70
80
90
100
110
120
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min)
%Accretion
Oxford
clay-solid
bar (heavy
weight)
Oxford
clay-hollow
cylinder
(light
weight)
Figure 26 – Effect of bar weight on accretion of Oxford Clay.
0
10
20
30
40
50
60
70
80
90
100
110
120
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min)
%Accretion
Arne clay-
solid bar
(heavy
weight)
Arne clay-
hollow
cylinder
(light
weight)
Figure 27 – Effect of bar weight on accretion of Arne Clay.
0
10
20
30
40
50
60
70
80
90
100
110
0 10 20 30 40 50 60
Time (min)
%Accretion
Blank
Polymer A
Polymer C
Polymer D
Figure 28 – Effect of encapsulating polymer on accretion-time
profile.
0
10
20
30
40
50
60
70
80
90
100
Oxford clay Arne clay
%Accretion-45min
Polymer A
Polymer C
Polymer D
Figure 29 – Effect of encapsulating polymer on accretion (t=45 min).
13. AADE-08-DF-HO-10 Agglomeration and Accretion of Drilled Cuttings in Water-based Fluids 13
0
10
20
30
40
50
60
70
80
90
100
110
0 1 2 3 4 5 6 7
Anticrete-1 (%vol)
%Accretion-30min
Accretion
of Oxford
clay
Figure 30 – Effect of anticrete concentration on accretion (t=30 min).
0
10
20
30
40
50
60
70
80
90
100
110
120
Oxford clay Arne clay
%Accretion-45min
Blank
3% Anticrete-1
3% Anticrete-2
Figure 31 – Effect of variations in anticrete composition on
accretion (t=45 min).
0
10
20
30
40
50
60
70
80
90
100
110
120
Oxford clay
%Accretion-30min
Blank
Lub-1
Lub-2
Lub-3
Lub-4
Figure 32 – Effect of lubricants on accretion (t=30 min).