This paper is a literature review on methods to control scale formation using various chemicals; and its economic feasibility in the petroleum industry.
DAMAGE ISSUES IMPACTING THE PRODUCTIVITY OF TIGHT GAS PRODUCING FORMATIONS; Formation Damage; Fracturing/Refracturing; Hydraulically Fractured; Tight Gas Reservoir; Economic Tight Gas Reservoir Production
DAMAGE ISSUES IMPACTING THE PRODUCTIVITY OF TIGHT GAS PRODUCING FORMATIONS; Formation Damage; Fracturing/Refracturing; Hydraulically Fractured; Tight Gas Reservoir; Economic Tight Gas Reservoir Production
The acidizing is pumping of the acids into the wellbore to remove near well formation damage and other damaging substances, matrix acidizing is applied primarily to remove skin damage that caused by drilling, completion, work over, well killing or injection fluids.
This project is concerned with carbonate reservoirs that exceeded in Kurdistan subsurface formations.
Conduct a case study using real industrial data of Arab-D formation (Ghawar oil field – Saudi Arabia) which has five water wells were treated with 50 gallon of HCl acid The treatment acid was placed with coiled tubing and foam was used as diverter. The foam was made from nitrogen, water and surfactants.
Water injection pressure, injection rate and injection flow meter profiles prior to and after the treatment for the five wells show optimistic results to an acceptable extent
In coiled tubing acid placement, the coiled tubing/borehole annulus is usually filled with acid which allow the acid to be in contact with the entire zone at bottom hole temperature condition. This reduces the degree of diversion effectiveness.
Recommend people who work in carbonate reservoirs they should done their work on petrophysical analysis and the porosity should not have exceeded by the acids
All petroleum companies aims to reach maximum production naturally by saving the pay zone characteristics to avoid using different enhanced oil recovery techniques.
Now it is possible by Special Core analysis techniques. Simple analysis on the surface; great time saving while drilling the subsurface.
Trying in this presentation to explain the main topics of (FDT).
For any further information, please contact me on : abdalrahmanibrahim209@gamil.com
This presentation tackles one of the problem in oil industry, which is sand that is produced in the oil wells. Brief description about the problem, its causes, effects and solutions are proposed.
DRILLING FLUIDS FOR THE HPHT ENVIRONMENTMohan Doshi
A BRIEF REVIEW OF THE DRILLING FLUIDS FOR DRILLING HPHT WELLS. HPHT WELLS ARE NOT BUSINESS AS USUAL AND THE SAME APPLIES TO HPHT DRILLING FLUIDS. THE FLUID CHEMISTRY AND THE FLUID COMPOSITION HAVE TO BE TAILORED TO MEET THE RIGORS OF THE HIGH TEMPERATURE ENVIRONMENT
ALL ABOUT NATURAL GAS : DEFINITION,FORMATION,PROPERTIES,COMPOSITION,PHASE BEHAVIOR ,CONDITIONING"DEHYDRATION ,SWETENING" AND FINAL PROCESSING TO END USER PRODUCTS
The acidizing is pumping of the acids into the wellbore to remove near well formation damage and other damaging substances, matrix acidizing is applied primarily to remove skin damage that caused by drilling, completion, work over, well killing or injection fluids.
This project is concerned with carbonate reservoirs that exceeded in Kurdistan subsurface formations.
Conduct a case study using real industrial data of Arab-D formation (Ghawar oil field – Saudi Arabia) which has five water wells were treated with 50 gallon of HCl acid The treatment acid was placed with coiled tubing and foam was used as diverter. The foam was made from nitrogen, water and surfactants.
Water injection pressure, injection rate and injection flow meter profiles prior to and after the treatment for the five wells show optimistic results to an acceptable extent
In coiled tubing acid placement, the coiled tubing/borehole annulus is usually filled with acid which allow the acid to be in contact with the entire zone at bottom hole temperature condition. This reduces the degree of diversion effectiveness.
Recommend people who work in carbonate reservoirs they should done their work on petrophysical analysis and the porosity should not have exceeded by the acids
All petroleum companies aims to reach maximum production naturally by saving the pay zone characteristics to avoid using different enhanced oil recovery techniques.
Now it is possible by Special Core analysis techniques. Simple analysis on the surface; great time saving while drilling the subsurface.
Trying in this presentation to explain the main topics of (FDT).
For any further information, please contact me on : abdalrahmanibrahim209@gamil.com
This presentation tackles one of the problem in oil industry, which is sand that is produced in the oil wells. Brief description about the problem, its causes, effects and solutions are proposed.
DRILLING FLUIDS FOR THE HPHT ENVIRONMENTMohan Doshi
A BRIEF REVIEW OF THE DRILLING FLUIDS FOR DRILLING HPHT WELLS. HPHT WELLS ARE NOT BUSINESS AS USUAL AND THE SAME APPLIES TO HPHT DRILLING FLUIDS. THE FLUID CHEMISTRY AND THE FLUID COMPOSITION HAVE TO BE TAILORED TO MEET THE RIGORS OF THE HIGH TEMPERATURE ENVIRONMENT
ALL ABOUT NATURAL GAS : DEFINITION,FORMATION,PROPERTIES,COMPOSITION,PHASE BEHAVIOR ,CONDITIONING"DEHYDRATION ,SWETENING" AND FINAL PROCESSING TO END USER PRODUCTS
How to write a scientific paper - PowerPoint to support the associated workbook handout. Workshop held as part of the USAID AIP Pakistan project. Workshop delivered by Tom Rost and Mark Bell.
Generally soaps create foam in water, but in present of some materials the foam creation is reduced and need more soap for producing foam, and this condition of water is called water hardness.
The presence of Calcium, Magnesium salt i.e. bicarbonates, sulphates, chloride in water is called causes of hardness of water. The water which contains these salts is called hard water. Hard water does not easily form lather with soap as the salt of Calcium and Magnesium react with soap to form insoluble organic salts.
Produced water reinjection (PWRI) is one of the most usual ways of produced water reuse in mature fields with high water cut.
The relationship between water quality and injectivity decline in wells is well known and it is particularly important in mature
fields, such as Barrancas, an old field located in Mendoza –Argentina, with more than 40 years of water injection. In this
reservoir significant injectivity losses were recorded when fresh water was replaced by produced water in the 90´s.
Formation Damage mechanism is mainly caused by external cake. Particles are principally, iron sulfide, calcium carbonate,
and oil droplets.
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.
Flow-Assurance Challenges in Gas-Storage Schemes in Depleted Reservoirs
This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 146239, "Flow-Assurance Challenges in Gas-Storage Schemes in Depleted Reservoirs," by Alireza Kazemi, SPE, and Bahman Tohidi, SPE, Hydrafact Ltd., and Emile Bakala Nyounary, Heriot-Watt University, prepared for the 2011 SPE Offshore Europe Oil and Gas Conference and Exhibition, Aberdeen, 6–8 September.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
MATATAG CURRICULUM: ASSESSING THE READINESS OF ELEM. PUBLIC SCHOOL TEACHERS I...NelTorrente
In this research, it concludes that while the readiness of teachers in Caloocan City to implement the MATATAG Curriculum is generally positive, targeted efforts in professional development, resource distribution, support networks, and comprehensive preparation can address the existing gaps and ensure successful curriculum implementation.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
Scale Formation problems in Oil & Gas Industry : Its reduction procedures by Chemical Introduction
1. Scale Formation problems in Oil & Gas Industry : Its reduction
procedures by Chemical Introduction
Oilfield scaling is serious for oil and gas industry. Every year problem with scale, costs industry millions
of dollars in damage and the lost production. The scale is one of the leading cause of worldwide decline.
In the North Sea area, 28% decline is related to the formation of scale.
The scale is an assemblage of deposits that clog perforations , casings, production tubings, valves ,
pumps and down holes, completion equipment, thereby clogging the well-bore and preventing fluid-
flow. Most scales found in oil fields forms either by direct precipitation from water that occurs naturally
in reservoir rocks or as a result of produced water becoming over-saturated with scale component when
two incompatible glasses of water meet downhole. Whenever an oil or gas well produces water or water
injection is used to enhance recovery, there is the possibility that scale will form.
The global cost of scale is estimated in more than USD 4 billion a year. Scale control form can for some
fields’ be the single biggest operational cost. The economic consequence of scale has estimated to have
the highest impact on North America and South America. In the coming years, scale costs will increase
as more as reservoir become mature and require pressure maintenance by water flooding to increase
recovery. The formation of scale may occur in the reservoir, in the wellbore or in the surface facilities.
Scale deposits may cause Formation damage by blocking pore throats, Flow restriction by blocking flow
lines and tubing, Completion damage by plugging perforations, screens, advanced completions, and
gravel packs, Choke and safety valve failure, Pump wear, Flow meter and instrumental failure,
Corrosion underneath scale deposits etc. Suspended solids can cause Plugged formation, Reduce
oil/water separator efficiency and Settlement in topside equipment.
This paper is a literature review on methods to control scale formation using various chemicals; and its
economic feasibility in the petroleum industry.
3. ANNEXURE 1 : SCALE FORMATION
PRINCIPLE
In a hydrocarbon reservoir, before a well is drilled and completed, the fluids in the formation is saturated
with dissolved salt. After the well is drilled the fluids are no longer remain in equilibrium and salts may
start to precipitate. This means that scale begins to form when such the solubility limit for one or more
than one components is exceeded .
Formation of scale depends on parameters, such as
change in pressure and temperature
degree of agitation/turbulence during formation of crystals
size and number of seed crystals
degree of super-saturation
change in pH of solution.
Where, and represent the salts where M being the cation with a positive charge and X is the
anion with a negative charge
Ksp is called the solubility product( equilibrium constant for the dissolution of the salt). The solubility
product is a measure of how many moles of ions per unit volume of solvent there can be in a system
before a salt precipitates out . If the saturation ratio equals 1.0 the solution is saturated and neither
precipitation nor dissolution of the salts will occur.
When the SR is less than 1.0 the solution is under-saturated and precipitation will not occur.
When the SR is greater than 1.0 the solution is oversaturated and precipitation of the salts may
occur ( SCALE FORMATION )
This will, however, depend on the kinetics of the precipitation reaction. Some salt do not start
spontaneous precipitation even if they are many hundred times super-saturated .
Produced water that goes through a pH shift, a temperature or pressure change or are in contact with
incompatible water, do not always produce scale, even though the produced water has become
oversaturated. This is because scale must grow from solution to form. The process is called nucleation
Saturation Ratio for salts = [ ][ ]/ Ksp
4. and is the first stage in forming scale. Nucleation is the creation of a sub particle or ion cluster consisting
of several individual scaling ions. There are two different nucleation processes called homogeneous
nucleation and heterogeneous nucleation. Homogeneous nucleation is a process where scale growth
starts in a supersaturated solution with ion pairs forming single crystals in solution Heterogeneous
nucleation is a process where scale crystals start to grow on substrates like metallic surfaces, sand grains
or on pre-existing surface defects.
PROCESSES OF SCALE FORMATION
Incompatible mixing
Scale from incompatible mixing occurs when two incompatible waters like injected seawater and
formation water gets mixed downhole. The produced water then gets oversaturated with scale
components. This happens because seawater has a high content or sulfate (SO4
-2
) and formation
water is rich in ions such as calcium (Ca+2
) and barium (Ba+2
). Mixing of these two waters leads
to precipitation of sulfate scales, such as BaSO4.
Evaporation
When a mixture of hydrocarbon gas and formation water is produced simultaneous, evaporation-
induced scale may occur. A pressure drop caused by reduced hydrostatic pressure leads to an
expansion of the hydrocarbon gas and the hot brine phase evaporates. The salt concentration will
5. then increase above the solubility limit and salt will precipitate. Halite (NaCl) scale in High
temperature High pressure (HTHP) wells is the most common scale type to be formed this way.
Auto-Scaling
This occurs when the natural water in the reservoir undergoes a change in pressure and/or
temperature when it is produced. Normally an increase in temperature tends to increase water
solubility of a salt which implies more ions gets dissolved at high temperatures. Similarly,
decrease in pressure tends to decrease the water solubility.
6. ANNEXURE 2 : PROBLEMS CAUSED BY SCALES
The formation of scale may occur in the reservoir, in the wellbore or in the surface facilities. Scale
deposits may cause
Formation damage by blocking pore throats.
Flow restriction by blocking flow lines and tubing.
Completion damage by plugging perforations, screens, advanced completions, and gravel packs.
Choke and safety valve failure
Pump wear
Flow meter and instrumental failure
Corrosion underneath scale deposits.
Suspended solids can cause
Plugged formation
Reduce oil/water separator efficiency
Settlement in topside equipment
7. ANNEXURE 3 : POTENTIAL SCALE FORMATION SITES
Case 1 : At the surface water injection facility where incompatible sources of water are mixed prior to
injection
Case 2 : In injection wells where the injected water starts to mix with the reservoir formation water.
Case 3 : Downhole in the reservoir where the injected water displaces formation water
Case 4 : Downhole in the reservoir where the mixed injected water and formation water are about to
reach the range of producing wells
Case 5 : Production tubing
Case 6 : At the connection of a branched zone where each branch produces different waters
Case 7 : At the manifold of producing zone where water is produced from different blocks within the
same producing zone.
Case 8 : At topside facility where produced fluids are mixed with different zones to separate oil and gas
from produced waters, or in pipelines that transport produced fluids to on-shore processing facilities.
8. ANNEXURE 4 : EXPERIMENTS CONDUCTED
• Collection of samples of casing and tubing was done by PDPU Alumni from ONGC Ahmedabad
(samples of KG Basin)
• Analysis of samples of casing and tubing for the identification of minerals was done in PDPU Solar
Department via X-Ray Diffractometer ( measuring instrument for analyzing the structure of a material from the scattering pattern
produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it )
• The analysis of the peaks obtained was done using the HIGHSCORE PLUS ( comprehensive phase
identification software used in XRD with additional functionalities of profile fitting, crystallographic and extended cluster analysis )
• The casing and tubing samples were tested in the chemical laboratory for the removal of scales by
increasing concentration of acids
• The variation of the removal of scales with concentration of acids was also noticed and the de-scaling
rate was calculated.
• After the completion of chemical experiment the samples underwent through XRD again and no or
fewer peaks were obtained which assured the removal of scales.
Scale inhibition is a chemical treatment used to control or prevent scale from forming in a
producing well. Scale inhibitors are water-soluble chemicals that are designed to prevent or
retard the nucleation and the crystal growth of inorganic scales. They can reduce the rate of scale
formation to almost zero. For a scale inhibitor to be considered as a good inhibitor it must be
Stable : It must be sufficiently stable tinder the conditions imposed.
Compatible : It must not interfere with the action of other oilfield chemicals, nor be affected . It must be
compatible with the chemical injection system under operating them.
Efficient : It must be able to inhibit the scale in question, irrespective of the mechanisms operating.
9. N
Y
N
Y
Y
Scale samples from Casing and Tubing
X-Ray Diffraction
Graph : Intensity vs. 2 θ/degree
Peaks obtained
Identification of scale type
Removal Techniques by use of HCl, HNO3,
HCOOH, H2SO4 , Oxalic acid and sulphamic
acid
Analysis of New Peaks
If
Changes in peak visible
Experiment successful
Feasibility and Viability Parameters with effective
cost reduction, optimizing removal of scales
Scales not removed by chemical
Introduction ; Alternate methods
recommended
Absence of potential scales
10. CASE 1 : CASING
1. Effect of concentration of HNO3 on weight loss of the sample
Concentration Time
(minutes)
Initial
weight
sample
( g )
Final
weight
sample
( g )
Dissolved
scale ( g )
%-
dissolution
Rate of
de-scaling
1% 60 5 4 1 20 0.3333
2% 60 5 3.6 1.4 28 0.466
3% 60 5 2.2 2.9 58 0.9666
4% 60 5 1.7 3.2 64 1.066
5% 60 5 0.9 4.1 82 1.366
2. Effect of concentration of HCl on weight loss of the sample
Concentration Time
(minutes)
Initial
weight
sample
( g )
Final
weight
sample
( g )
Dissolved
scale ( g )
%-
dissolution
Rate of
de-scaling
1% 60 5 3 2 40 0.666
2% 60 5 2.5 2.5 50 0.833
3% 60 5 1.4 3.4 68 1.133
4% 60 5 1 4 80 1.333
5% 60 5 0.3 4.7 94 1.566
3. Effect of concentration of H2SO4 on weight loss of the sample
Concentration Time
(minutes)
Initial
weight
sample
( g )
Final
weight
sample
( g )
Dissolved
scale ( g )
%-
dissolution
Rate of
de-
scaling
1% 60 5 5 0 0 0
2% 60 5 5 0 0 0
3% 60 5 4.4 0.6 12 1.932
4% 60 5 4.5 0.5 10 0.166
5% 60 5 4.5 0.5 10 0.166
4. Effect of concentration of HCOOH on weight loss of the sample
Concentration Time
(minutes)
Initial
weight
sample (
g )
Final
weight
sample (
g )
Dissolved
scale ( g )
%-
dissolution
Rate of
de-scaling
1% 60 5 4 1 20 0.333
2% 60 5 4 1 20 0.333
3% 60 5 3.5 1.5 30 0.5
4% 60 5 3 2 40 0.666
11. 5% 60 5 2.7 1.3 26 0.433
5. Dissolved mass of scale in casing in different acid solution for 5g sample in 60 mins.
Concentration Time
(minutes)
% - dissolution
HNO3 HCl H2SO4 HCOOH
1% 60 1 2 0 1
2% 60 1.4 2.5 0 1
3% 60 2.9 3.4 0.5 1.5
4% 60 3.2 4 0.5 2
5% 60 4.1 4.7 0.5 2.3
0
20
40
60
80
100
1 2 3 4 5
Dissolvedscale(%)
Chemical Treatment on casing scale sample
HCOOH
H2SO4
HCl
HNO3
Formulas
Average specific rate of de-scaling ( R ) = ( mloss / msample ) x t
12. CASE 2 : TUBINGS
1. Dissolved mass of scale in casing in different acid solution for 5g sample in 60 mins
Concentration Time
(minutes)
% - dissolution
HNO3 HCl H2SO4 HCOOH
1% 60 0.5 1.5 0 0
2% 60 0.92 2 0 0.24
3% 60 1.4 2.9 0.2 0.76
4% 60 1.98 3.5 0.34 1.12
5% 60 2.77 4.2 0.51 1.76
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5
DissolvedScale(%)
Chemical Treatment on tubing scale samples
HCOOH
H2SO4
HCl
HNO3
13. CASE 3 : On an average scale dissolution ( % ) vs Concentration of various acids can be inferred as
14. CONCLUSIONS
In order to prevent scale economically, inorganic acids ( except H2SO4 ) proved to be more effective as
compared to organic acids. HCl and HNO3 are better candidates to be used for chemical de-scaling of
tubing and casing. HCl may provide 30-50% saving on circulation time as compared to HNO3 based on
rate of dissolution. XRD plots also shown great variation after chemical treatment signifying scale
removal.
Fig. represents XRD plots before and after acid treatment in CASINGS
Fig. represents XRD plots before and after acid treatment in TUBINGS
15. REFERENCE
1. Femier WW and M. Ziauddin, removal and inhibition of organic scale in oilfield environment
2008.
2. Kelund M.A Productions chemical for oil and gas Industry 2009
3. Norwegian Petroleum Directorate
4. Al. Salami, AR and AA Momen, Downhole and Topside scale challenge “ Removal, prevention
and inhibition technology for scales “ , 2000
5. Crabtree, fighting scale- Removal and Prevention in Oilfield review , 1999
6. petrowiki.org/Scale_problems_in_production
7. www.kemira.com/en/industries-applications/Pages/scale-inhibition-production.aspx
8. Prediction of Scale Formation Problems in Oil Reservoirs and Production Equipment due
to Injection of Incompatible Waters Authors J. Moghadasi, A. Sharif, H. Müuller-Steinhagen,
M. Jamialahmad