Porosity is a measure of the void spaces in a rock that can contain fluids. It is calculated as the ratio of pore volume to bulk volume. Effective porosity refers only to interconnected pores that can produce fluids from a well. Total porosity includes all pores, but some may be isolated. Primary porosity forms during deposition, while secondary porosity forms through geological processes after deposition. Porosity depends on factors like grain size, shape, packing, and cementation. Permeability measures a rock's ability to transmit fluids and depends on pore connectivity and size. Darcy's law relates fluid flow through a porous medium to properties like permeability, fluid viscosity, pressure difference, and length.
Henry Darcy developed Darcy's law in 1856 based on experiments studying the flow of water through sand filters. Darcy's law states that for laminar flow through saturated soil or porous media, the discharge rate is proportional to the hydraulic gradient. The law is expressed mathematically as Q=KA(h1-h2)/L, where Q is the flow rate, K is the hydraulic conductivity, A is the cross-sectional area, h1 and h2 are the water levels, and L is the distance between them. Darcy's law is valid for laminar flow in saturated, homogeneous, isotropic porous media, but may not apply to turbulent or unsaturated flow conditions. It has wide applications in areas like
Seismic surveys use seismic waves to image the subsurface. There are two main types: refraction surveys use refracted waves to determine shallow layer velocities, while reflection surveys use reflected waves to image deeper geological structures and boundaries between rock layers. Reflection surveys require more receivers and sources to adequately image the subsurface, making the data acquisition and processing more complex but able to image deeper targets compared to refraction surveys.
Porosity Permeability Relationship in carbonate rock pptAmar Gaikwad
A information about porosity and permeability in a carbonate rock. in which we studied the porosity measurement , carbonate rock ,permeability and correlation between them.
Engineering geology is the application of the science of geology to the technology of ground engineering. The subject requires a comprehensive knowledge of geology, as well as an understanding of engineering properties and behaviour of the geological materials. The practice involves site investigation and site characterization specific to the needs of the engineering project. The geotechnical engineer plays a key role in most civil engineering projects as most structures are built on or in the ground. Geotechnical engineers assess the properties and behaviour of soil and rock formations.
This document discusses geophysical prospecting methods used to study the structure of the earth's crust. It focuses on electrical resistivity methods, including resistivity profiling and resistivity sounding. Resistivity profiling uses constant electrode spacing to investigate lateral variations in soil resistivity along lines or parallel lines. Resistivity sounding varies electrode spacing with readings taken at the same point to determine resistivity variation with depth. Both methods can be used to distinguish soil layers and prospect for resources like ores, sand, and gravel.
COAL MICROLITHOTYPES AND THEIR USAGE IN INTERPRETING DEPOSITION ENVIRONMENTOlusegun Ayobami Olatinpo
This document discusses coal microlithotypes and how their analysis can be used to interpret depositional environments. It defines microlithotypes as natural rock associations found within coal that are differentiated based on maceral percentages. Specific microlithotypes form from different plant communities and depositional conditions. Analyzing the microlithotype composition of coal samples can provide insights into the swamp environment where peat formed, such as forested, reed, or open water settings. This information is valuable for geological research and coal quality evaluation.
It includes the definition, properties, classification of groundwater with appropriate examples and figures in details. It also deals about the formation of groundwater. The properties of aquifers (all of 7) are described here in details with figures and mathematical terms.
Henry Darcy developed Darcy's law in 1856 based on experiments studying the flow of water through sand filters. Darcy's law states that for laminar flow through saturated soil or porous media, the discharge rate is proportional to the hydraulic gradient. The law is expressed mathematically as Q=KA(h1-h2)/L, where Q is the flow rate, K is the hydraulic conductivity, A is the cross-sectional area, h1 and h2 are the water levels, and L is the distance between them. Darcy's law is valid for laminar flow in saturated, homogeneous, isotropic porous media, but may not apply to turbulent or unsaturated flow conditions. It has wide applications in areas like
Seismic surveys use seismic waves to image the subsurface. There are two main types: refraction surveys use refracted waves to determine shallow layer velocities, while reflection surveys use reflected waves to image deeper geological structures and boundaries between rock layers. Reflection surveys require more receivers and sources to adequately image the subsurface, making the data acquisition and processing more complex but able to image deeper targets compared to refraction surveys.
Porosity Permeability Relationship in carbonate rock pptAmar Gaikwad
A information about porosity and permeability in a carbonate rock. in which we studied the porosity measurement , carbonate rock ,permeability and correlation between them.
Engineering geology is the application of the science of geology to the technology of ground engineering. The subject requires a comprehensive knowledge of geology, as well as an understanding of engineering properties and behaviour of the geological materials. The practice involves site investigation and site characterization specific to the needs of the engineering project. The geotechnical engineer plays a key role in most civil engineering projects as most structures are built on or in the ground. Geotechnical engineers assess the properties and behaviour of soil and rock formations.
This document discusses geophysical prospecting methods used to study the structure of the earth's crust. It focuses on electrical resistivity methods, including resistivity profiling and resistivity sounding. Resistivity profiling uses constant electrode spacing to investigate lateral variations in soil resistivity along lines or parallel lines. Resistivity sounding varies electrode spacing with readings taken at the same point to determine resistivity variation with depth. Both methods can be used to distinguish soil layers and prospect for resources like ores, sand, and gravel.
COAL MICROLITHOTYPES AND THEIR USAGE IN INTERPRETING DEPOSITION ENVIRONMENTOlusegun Ayobami Olatinpo
This document discusses coal microlithotypes and how their analysis can be used to interpret depositional environments. It defines microlithotypes as natural rock associations found within coal that are differentiated based on maceral percentages. Specific microlithotypes form from different plant communities and depositional conditions. Analyzing the microlithotype composition of coal samples can provide insights into the swamp environment where peat formed, such as forested, reed, or open water settings. This information is valuable for geological research and coal quality evaluation.
It includes the definition, properties, classification of groundwater with appropriate examples and figures in details. It also deals about the formation of groundwater. The properties of aquifers (all of 7) are described here in details with figures and mathematical terms.
Paleobathymetry is the study of ancient ocean depths and seafloor topography. Benthic foraminifera, which live on the seafloor, are commonly used to determine paleodepths because their distributions relate to water conditions. Different species of foraminifera are found within specific depth ranges, such as spherical alveolinids from 0-30 meters and elongated alveolinids from 30-50 meters. Paleobathymetric techniques are strengthened as the relationship between foraminiferal distributions and oceanographic changes are better understood.
This document discusses various geophysical well logging methods used to delineate aquifers and estimate water quality, including resistivity, spontaneous potential, radioactivity, neutron, temperature, and fluid resistivity logging. Resistivity logging measures the resistivity of formations and can help determine lithology, porosity, and fluid salinity. Spontaneous potential logging indicates bed boundaries and distinguishes shale from permeable rocks. Radioactivity logging uses natural gamma rays or gamma-gamma techniques to identify lithology and determine porosity. Neutron logging measures hydrogen content to estimate porosity and moisture levels. Temperature and fluid resistivity logging provide additional information about groundwater. These geophysical logs provide critical subsurface data for groundwater exploration and management.
Foraminifera are single-celled organisms that produce shells or tests made of calcium carbonate, agglutinated particles, or organic materials. They are abundant microfossils commonly used for biostratigraphy, paleoecology, and paleobiogeography reconstructions. Foraminifera have a wide environmental range and different species are found in different environments and time periods, making them useful for correlating and dating rock units. Their tests also provide information about past ocean conditions like temperature, salinity, and circulation patterns. Foraminifera analysis is applied to oil exploration by helping determine the age and environment of rock samples from drill cores.
This document provides information about volcaniclastic rocks and pyroclastic materials. It defines pyroclastic rocks as being composed of volcanic materials and volcaniclastic rocks as pyroclastic materials that have been transported and reworked. Pyroclastic materials include volcanic bombs, lapilli, ash, and ignimbrites. These materials are classified based on size. Volcaniclastic rocks include agglomerates, tuffs, and other deposits that form from pyroclastic flows and ash falls.
This document provides an overview of various groundwater exploration methods, including surface and subsurface techniques. Surface methods involve minimal facilities and include geomorphological analysis of landforms, geological and structural mapping, soil and vegetation analysis, remote sensing, and surface geophysical methods like electrical resistivity and seismic surveys. Subsurface methods like borehole logging and test drilling provide direct observations but are more expensive. Together, a multi-method approach can be used to explore groundwater resources and locate potential zones for development.
Groundwater province is an area or region in which geology and climate combine to produce groundwater conditions consistent enough to permit useful generalisations.
Porosity is a measure of the void spaces in a rock that can contain fluids. It is calculated as the ratio of pore volume to bulk volume. Effective porosity refers only to interconnected pores that can produce fluids from a well. Total porosity includes all pores, but some may be isolated. Primary porosity forms during deposition, while secondary porosity forms through geological processes after deposition. Porosity depends on factors like grain size, shape, packing, and cementation. Permeability measures a rock's ability to transmit fluids and depends on pore connectivity and size. Darcy's law describes fluid flow through porous media and permeability can be measured experimentally under steady-state conditions.
The document discusses considerations for selecting dam and reservoir sites from a geological perspective. It defines different dam types including gravity, buttress, arch, and earth dams. Key factors for dam site selection include the underlying rock and soil composition and structure, with impermeable and stable foundations being important. Dams should avoid faults, fractures, and areas prone to erosion or earthquakes. The reservoir site selection process also aims to minimize land usage and sediment intake while ensuring adequate storage capacity.
Kerogen is composed of the insoluble organic matter in sedimentary rocks that is capable of generating petroleum. It is formed from the decomposed remains of organisms like bacteria, algae, and plants. Kerogen is classified into four main types - Type I kerogen forms from algal matter and yields large amounts of oil; Type II kerogen is a mix of marine and terrestrial organic matter and is the most prolific source; Type III kerogen derives from woody plant debris and yields more gas; Type IV kerogen is highly carbonaceous but incapable of generating petroleum. The composition and source of the organic matter determines the type of kerogen formed and ultimately influences the hydrocarbon products generated during maturation.
Sedimentary facies refer to rock or sediment bodies that are distinguished by their composition, texture, structures and other features related to the depositional environment. Key aspects of facies include grain size, sorting, fossils and bedding. Individual facies represent specific depositional conditions. Multiple genetically-related facies comprise a facies association representing a depositional system. Facies successions occur at different scales from individual systems to basin-scale sequences reflecting changes in sea level over time.
This document provides an overview of laboratory and field testing methods for rocks. It discusses index property tests such as unit weight, porosity, permeability, electrical resistivity, and sonic velocity that are used to characterize and classify rocks. It also describes mechanical property tests like unconfined compressive strength testing, triaxial testing, point load strength testing, and beam bending tests. Common field testing methods mentioned include pressuremeter testing, in-situ direct shear testing, and hydraulic fracturing. The document provides details on sample preparation, equipment used, procedures, and how to calculate and interpret results for different rock property tests.
This document provides an overview of structural geology concepts including folds, faults, strike, dip, and fold classification. It discusses that structural geology studies secondary rock structures like folds and faults, and defines key terms like outcrop, strike, and dip. It also categorizes and describes various types of folds such as anticlines, synclines, symmetrical/asymmetrical, plunging/non-plunging, open/closed, and domes and basins. The causes of folding from tectonic forces and effects on erosion are summarized. Faults are described as unfavorable for construction.
Contact metamorphism occurs where cooler country rocks are thermally altered by nearby intrusive bodies. The textures that develop under these low-pressure conditions typically lack strain and preserve relict features. Common textures include granoblastic polygonal textures in isotropic minerals like quartz, decussate textures in anisotropic minerals, and porphyroblasts. With increasing metamorphic grade, recrystallization becomes more prominent, grains grow larger, and evidence of strain decreases.
Reflecting method of seismic prospectingPramoda Raj
This document provides an overview of seismic prospecting methods. It discusses the different types of seismic waves, including P-waves, S-waves, and surface waves. The seismic reflecting method is described as using controlled seismic sources to generate waves that reflect off underground formations and are detected by sensors at the surface. Reflection seismology can be used to map subsurface geology at various depths for applications like hydrocarbon exploration, engineering surveys, and studying crustal structures. In summary, the document outlines seismic prospecting techniques, focusing on the seismic reflecting method of using controlled sources and detecting reflected waves.
Rock mass classification or rock mass rating of rock materials in civil and m...Ulimella Siva Sankar
1. Rock mass classification systems provide a methodology to characterize rock mass strength using simple measurements and allow geologic data to be converted into quantitative engineering parameters.
2. The most widely used systems are RQD, RMR, and Q-system which evaluate factors like rock quality, joint conditions, and groundwater to determine an overall classification.
3. Classification systems estimate the rock mass strength and deformability, which can then be input into numerical models to design underground mine openings and support requirements.
Mineral exploration is the process of finding ore deposits to mine through organized prospecting. The most crucial part is selecting suitable areas based on geology and terrain to make exploration easy, cheap, and quick. Common exploration methods include geophysics using physical measurements, remote sensing using aerial technologies like satellites, and geochemical methods to identify anomalies within mineral deposit areas. The ultimate goal of exploration is the extraction and profitable sale of identified minerals, though there are risks from changing prices and weather conditions that could delay revenue generation.
This document discusses metamorphic textures, which refer to the physical appearance or arrangement of minerals in metamorphic rocks at the microscopic level. There are several types of textures that can form during metamorphism due to factors like heat, pressure, and chemically active fluids. Typomorphic textures are characteristic of metamorphism and include porphyroblastic, mortar, and granoblastic textures. Relict textures are inherited from the original rock, such as ophitic or porphyritic textures. Reaction textures involve chemical reactions between minerals, forming textures like coronas or reaction rims. The document provides examples of different textures and concludes that textures provide information about the metamorphic conditions and original rock type.
The document discusses the electrical resistivity method for geophysical investigations. It begins by defining electrical resistivity and describing how it is measured. Resistivity depends on factors like moisture content and porosity. Common materials and their typical resistivity ranges are provided. The document then describes the principles and applications of two electrical methods - equipotential and resistivity. Key aspects covered include how resistivity is used to interpret subsurface layers and detect anomalies. The document concludes by outlining several applications of electrical resistivity methods like mapping stratigraphy and aquifers.
This document discusses porosity of reservoir rocks. It defines porosity as the ratio of pore volume to bulk volume of a rock. Porosity can be classified as original or induced. Factors that affect porosity include particle size, sorting, packing, cementation and stress. Porosity is important for reservoir engineering calculations as it represents the pore space occupied by fluids. It is measured through core analysis, well logging, or well testing. Laboratory methods to determine porosity include measuring bulk volume through fluid displacement or gravimetric techniques and pore volume through fluid saturation.
Porosity is a key property of reservoir rocks that represents the pore volume as a fraction of bulk volume. It can be measured through laboratory analysis of rock samples or estimated from well logs. Several factors influence porosity, including grain size, sorting, cementation, and compaction. Common techniques to determine porosity include measuring pore volume directly through fluid extraction or injection methods, or calculating it by finding the grain volume and subtracting it from bulk volume. Understanding porosity distribution is important for reservoir characterization and fluid flow modeling.
Paleobathymetry is the study of ancient ocean depths and seafloor topography. Benthic foraminifera, which live on the seafloor, are commonly used to determine paleodepths because their distributions relate to water conditions. Different species of foraminifera are found within specific depth ranges, such as spherical alveolinids from 0-30 meters and elongated alveolinids from 30-50 meters. Paleobathymetric techniques are strengthened as the relationship between foraminiferal distributions and oceanographic changes are better understood.
This document discusses various geophysical well logging methods used to delineate aquifers and estimate water quality, including resistivity, spontaneous potential, radioactivity, neutron, temperature, and fluid resistivity logging. Resistivity logging measures the resistivity of formations and can help determine lithology, porosity, and fluid salinity. Spontaneous potential logging indicates bed boundaries and distinguishes shale from permeable rocks. Radioactivity logging uses natural gamma rays or gamma-gamma techniques to identify lithology and determine porosity. Neutron logging measures hydrogen content to estimate porosity and moisture levels. Temperature and fluid resistivity logging provide additional information about groundwater. These geophysical logs provide critical subsurface data for groundwater exploration and management.
Foraminifera are single-celled organisms that produce shells or tests made of calcium carbonate, agglutinated particles, or organic materials. They are abundant microfossils commonly used for biostratigraphy, paleoecology, and paleobiogeography reconstructions. Foraminifera have a wide environmental range and different species are found in different environments and time periods, making them useful for correlating and dating rock units. Their tests also provide information about past ocean conditions like temperature, salinity, and circulation patterns. Foraminifera analysis is applied to oil exploration by helping determine the age and environment of rock samples from drill cores.
This document provides information about volcaniclastic rocks and pyroclastic materials. It defines pyroclastic rocks as being composed of volcanic materials and volcaniclastic rocks as pyroclastic materials that have been transported and reworked. Pyroclastic materials include volcanic bombs, lapilli, ash, and ignimbrites. These materials are classified based on size. Volcaniclastic rocks include agglomerates, tuffs, and other deposits that form from pyroclastic flows and ash falls.
This document provides an overview of various groundwater exploration methods, including surface and subsurface techniques. Surface methods involve minimal facilities and include geomorphological analysis of landforms, geological and structural mapping, soil and vegetation analysis, remote sensing, and surface geophysical methods like electrical resistivity and seismic surveys. Subsurface methods like borehole logging and test drilling provide direct observations but are more expensive. Together, a multi-method approach can be used to explore groundwater resources and locate potential zones for development.
Groundwater province is an area or region in which geology and climate combine to produce groundwater conditions consistent enough to permit useful generalisations.
Porosity is a measure of the void spaces in a rock that can contain fluids. It is calculated as the ratio of pore volume to bulk volume. Effective porosity refers only to interconnected pores that can produce fluids from a well. Total porosity includes all pores, but some may be isolated. Primary porosity forms during deposition, while secondary porosity forms through geological processes after deposition. Porosity depends on factors like grain size, shape, packing, and cementation. Permeability measures a rock's ability to transmit fluids and depends on pore connectivity and size. Darcy's law describes fluid flow through porous media and permeability can be measured experimentally under steady-state conditions.
The document discusses considerations for selecting dam and reservoir sites from a geological perspective. It defines different dam types including gravity, buttress, arch, and earth dams. Key factors for dam site selection include the underlying rock and soil composition and structure, with impermeable and stable foundations being important. Dams should avoid faults, fractures, and areas prone to erosion or earthquakes. The reservoir site selection process also aims to minimize land usage and sediment intake while ensuring adequate storage capacity.
Kerogen is composed of the insoluble organic matter in sedimentary rocks that is capable of generating petroleum. It is formed from the decomposed remains of organisms like bacteria, algae, and plants. Kerogen is classified into four main types - Type I kerogen forms from algal matter and yields large amounts of oil; Type II kerogen is a mix of marine and terrestrial organic matter and is the most prolific source; Type III kerogen derives from woody plant debris and yields more gas; Type IV kerogen is highly carbonaceous but incapable of generating petroleum. The composition and source of the organic matter determines the type of kerogen formed and ultimately influences the hydrocarbon products generated during maturation.
Sedimentary facies refer to rock or sediment bodies that are distinguished by their composition, texture, structures and other features related to the depositional environment. Key aspects of facies include grain size, sorting, fossils and bedding. Individual facies represent specific depositional conditions. Multiple genetically-related facies comprise a facies association representing a depositional system. Facies successions occur at different scales from individual systems to basin-scale sequences reflecting changes in sea level over time.
This document provides an overview of laboratory and field testing methods for rocks. It discusses index property tests such as unit weight, porosity, permeability, electrical resistivity, and sonic velocity that are used to characterize and classify rocks. It also describes mechanical property tests like unconfined compressive strength testing, triaxial testing, point load strength testing, and beam bending tests. Common field testing methods mentioned include pressuremeter testing, in-situ direct shear testing, and hydraulic fracturing. The document provides details on sample preparation, equipment used, procedures, and how to calculate and interpret results for different rock property tests.
This document provides an overview of structural geology concepts including folds, faults, strike, dip, and fold classification. It discusses that structural geology studies secondary rock structures like folds and faults, and defines key terms like outcrop, strike, and dip. It also categorizes and describes various types of folds such as anticlines, synclines, symmetrical/asymmetrical, plunging/non-plunging, open/closed, and domes and basins. The causes of folding from tectonic forces and effects on erosion are summarized. Faults are described as unfavorable for construction.
Contact metamorphism occurs where cooler country rocks are thermally altered by nearby intrusive bodies. The textures that develop under these low-pressure conditions typically lack strain and preserve relict features. Common textures include granoblastic polygonal textures in isotropic minerals like quartz, decussate textures in anisotropic minerals, and porphyroblasts. With increasing metamorphic grade, recrystallization becomes more prominent, grains grow larger, and evidence of strain decreases.
Reflecting method of seismic prospectingPramoda Raj
This document provides an overview of seismic prospecting methods. It discusses the different types of seismic waves, including P-waves, S-waves, and surface waves. The seismic reflecting method is described as using controlled seismic sources to generate waves that reflect off underground formations and are detected by sensors at the surface. Reflection seismology can be used to map subsurface geology at various depths for applications like hydrocarbon exploration, engineering surveys, and studying crustal structures. In summary, the document outlines seismic prospecting techniques, focusing on the seismic reflecting method of using controlled sources and detecting reflected waves.
Rock mass classification or rock mass rating of rock materials in civil and m...Ulimella Siva Sankar
1. Rock mass classification systems provide a methodology to characterize rock mass strength using simple measurements and allow geologic data to be converted into quantitative engineering parameters.
2. The most widely used systems are RQD, RMR, and Q-system which evaluate factors like rock quality, joint conditions, and groundwater to determine an overall classification.
3. Classification systems estimate the rock mass strength and deformability, which can then be input into numerical models to design underground mine openings and support requirements.
Mineral exploration is the process of finding ore deposits to mine through organized prospecting. The most crucial part is selecting suitable areas based on geology and terrain to make exploration easy, cheap, and quick. Common exploration methods include geophysics using physical measurements, remote sensing using aerial technologies like satellites, and geochemical methods to identify anomalies within mineral deposit areas. The ultimate goal of exploration is the extraction and profitable sale of identified minerals, though there are risks from changing prices and weather conditions that could delay revenue generation.
This document discusses metamorphic textures, which refer to the physical appearance or arrangement of minerals in metamorphic rocks at the microscopic level. There are several types of textures that can form during metamorphism due to factors like heat, pressure, and chemically active fluids. Typomorphic textures are characteristic of metamorphism and include porphyroblastic, mortar, and granoblastic textures. Relict textures are inherited from the original rock, such as ophitic or porphyritic textures. Reaction textures involve chemical reactions between minerals, forming textures like coronas or reaction rims. The document provides examples of different textures and concludes that textures provide information about the metamorphic conditions and original rock type.
The document discusses the electrical resistivity method for geophysical investigations. It begins by defining electrical resistivity and describing how it is measured. Resistivity depends on factors like moisture content and porosity. Common materials and their typical resistivity ranges are provided. The document then describes the principles and applications of two electrical methods - equipotential and resistivity. Key aspects covered include how resistivity is used to interpret subsurface layers and detect anomalies. The document concludes by outlining several applications of electrical resistivity methods like mapping stratigraphy and aquifers.
This document discusses porosity of reservoir rocks. It defines porosity as the ratio of pore volume to bulk volume of a rock. Porosity can be classified as original or induced. Factors that affect porosity include particle size, sorting, packing, cementation and stress. Porosity is important for reservoir engineering calculations as it represents the pore space occupied by fluids. It is measured through core analysis, well logging, or well testing. Laboratory methods to determine porosity include measuring bulk volume through fluid displacement or gravimetric techniques and pore volume through fluid saturation.
Porosity is a key property of reservoir rocks that represents the pore volume as a fraction of bulk volume. It can be measured through laboratory analysis of rock samples or estimated from well logs. Several factors influence porosity, including grain size, sorting, cementation, and compaction. Common techniques to determine porosity include measuring pore volume directly through fluid extraction or injection methods, or calculating it by finding the grain volume and subtracting it from bulk volume. Understanding porosity distribution is important for reservoir characterization and fluid flow modeling.
Fundamentals of Petroleum Engineering Module 3Aijaz Ali Mooro
This document provides an overview of reservoir rock and fluid properties. It discusses key concepts such as porosity, permeability, fluid interactions, and reservoir drive mechanisms. Porosity refers to the void spaces in rock that can store hydrocarbons. Permeability measures how easily fluids can flow through rock. The document also examines factors that affect porosity and different types of porosity and permeability. Reservoir drive mechanisms like solution gas, gas cap, and water drives are explained. Finally, it briefly discusses secondary and tertiary recovery methods used to improve oil extraction rates.
Porosity and permeability are key properties that determine whether rock can effectively store and transmit hydrocarbons. Porosity refers to void space that can hold fluids, while permeability refers to how easily fluids can flow through interconnected pore spaces. There are different types of porosity and permeability based on pore connectivity and origin. Important reservoir rocks include clastic rocks like sandstone and carbonate rocks, which have sufficient original or secondary porosity. Hydrocarbons generated in source rocks can migrate through reservoir rocks, becoming trapped in structural or stratigraphic traps created by geological processes like folding or variations in rock layers.
Oslo university basic well log analysis introductionJavier Espinoza
The document provides an overview of basic well log analysis methods used to derive petrophysical properties for hydrocarbon exploration. It discusses the borehole environment, including invasion of drilling mud into formations. It also covers open and cased hole logs, the three main types of logs (electrical, nuclear, acoustic), and how logs are used to infer properties like lithology, porosity, permeability, water saturation, and resistivity. Key concepts discussed include Archie's law, borehole resistivity profiles, and correcting mud and water resistivities for formation temperature.
Porosity as a reservoir property (notes by Dr. Adenutsi).pdfalbertmamzie08
Porosity is the ratio of pore volume to bulk volume in a reservoir rock, expressed as a percentage. It measures the rock's storage capacity for fluids. There are three types of pores: interconnected, dead-end, and isolated. Total porosity includes all pore types, while effective porosity includes interconnected and dead-end pores that can transmit fluids. Porosity is influenced by factors like grain packing, sorting, cementation, and compaction. It can be measured in a lab through bulk volume, pore volume, and grain volume measurements on core plugs.
Presentation-Formation_Evaluation by well logging _ENI.pdfssuser00e626
The document provides an overview of formation evaluation using well logging. It discusses how formation evaluation aims to determine reservoir dimensions, original hydrocarbon in place, and productivity. Well logs measure physical properties like resistivity, density, and radioactivity that are analyzed through petrophysical interpretation to estimate parameters like porosity, permeability, and water saturation. The document outlines different well log tools and applications, principles of resistivity and its relationship to water saturation, and concepts important for well log analysis and interpretation.
This document provides information on various topics related to well planning and design, including:
- Well data requirements such as detailed lithology, formation fluids, reservoir data, and pressure data.
- Global basin screening, basin analysis, play analysis, prospect analysis, rock types, and reactive formations.
- Exploration strategy, including global basin analysis, basin analysis, play analysis, prospect analysis, and prospect volume estimation.
- Pore pressure and fracture pressure determination, including leakage tests to estimate the fracture gradient at casing seats.
Soil water exists in three forms: free water, gravitational water, and held water. Held water includes adsorbed water forming thin films around soil grains and structural water chemically bonded to minerals. Capillary water is held tightly in small pores by hydrogen bonding, with height of rise inversely related to pore radius. Permeability is a soil property allowing water flow through interconnected voids and is important for engineering problems like seepage and drainage. Darcy's law states discharge is proportional to hydraulic gradient. Permeability is determined through constant head and falling head laboratory tests, with constant head used for permeable soils and falling head for less permeable soils.
This document discusses tight reservoirs, which are reservoirs with very low permeability (less than 0.1 mD) and porosity (less than 10%). It defines tight gas reservoirs, tight oil reservoirs, and the characteristic properties of tight reservoirs, such as low porosity and permeability. It also discusses the importance of logging, factors to consider for tight reservoirs like geologic and reservoir properties, and techniques used to produce from tight reservoirs, including hydraulic fracturing and horizontal drilling. Tight reservoirs account for a large portion of remaining oil and gas reserves and require advanced drilling and completion techniques to produce economically.
This document provides an overview of key concepts in petroleum engineering, including permeability, geophysics techniques for oil and gas exploration like seismic surveys, and reservoir engineering essentials. It discusses permeability measurement methods, factors that affect permeability, and types of permeability. It also summarizes different geophysics techniques like seismic surveys, gravity surveys, electromagnetic surveys, and magnetic surveys. Finally, it outlines the essential elements and processes for hydrocarbon accumulation, including the need for a trap, reservoir, source rock, and seal.
This document provides an overview of various petrophysical concepts including porosity, permeability, water saturation, and shale volume. It discusses different methods for calculating porosity from density logs, neutron-density logs, and sonic logs. It also covers calculating shale volume from neutron-density logs and gamma ray logs. Permeability is discussed in relation to flow zone indicator, porosity, irreducible water saturation, and NMR logs. Water saturation models including Archie and shaly sand models are also mentioned.
The document discusses the design of tube wells, including analyzing particle size of aquifers, designing the housing pipe, casing, and well screen based on particle size analysis. Key steps include: 1) Analyzing aquifer particle size distribution to determine effective size and uniformity, 2) Designing housing pipe and casing based on pump size and desired flow rate, 3) Selecting strata to screen based on permeability as determined by effective size and uniformity.
Episode 44 : Flow Behavior of Granular Materials and PowdersPart IIISAJJAD KHUDHUR ABBAS
Episode 44 : Flow Behavior of Granular Materials and PowdersPart III
Law of hydrodynamics do not apply to the flow of solid granular materials through orifices:
Pressure is not distributed equally in all directions due to the development of arches and to frictional forces between the granules.
The rate of flow is not proportional to the head, except at heads smaller than the container diameter.
No provision is made in hydrodynamics for size and shape of particles, which greatly influence the flow rate.
SAJJAD KHUDHUR ABBAS
Ceo , Founder & Head of SHacademy
Chemical Engineering , Al-Muthanna University, Iraq
Oil & Gas Safety and Health Professional – OSHACADEMY
Trainer of Trainers (TOT) - Canadian Center of Human
Development
The document discusses various tests that are conducted on sand to determine its suitability for use in concrete. The key tests described are: moisture content, clay content, grain size distribution, permeability, strength, refractoriness, hardness, silt content, and bulking. These tests are important because sand properties like cleanliness, grain shape and size distribution influence the strength and durability of hardened concrete. Impurities in sand like silt or organic matter can weaken the final concrete.
This document discusses porosity and permeability in sedimentary rocks. It defines porosity as the volume of void space available to contain fluids, and permeability as how easily fluids can pass through porous materials. Several factors that influence porosity are described, including packing density, grain size/shape, sorting, and post-burial changes due to compaction, cementation, clay formation, fracturing, and solution. Methods for determining porosity from well logs, including density, sonic, and neutron logs, are also summarized.
1. Porosity is a measure of the void spaces in a rock, but it can be measured in different ways that give different values.
2. The most common method uses helium injection to measure total porosity, but other methods like mercury injection and imaging can provide more details on pore size distribution and different types of porosity.
3. The correct measurement and characterization of porosity is important for reservoir evaluation and modeling since porosity determines properties like permeability and fluid storage capacity.
Porosity refers to the pore space within a rock that can be occupied by fluids like water or gas. It is calculated as a percentage by dividing the pore volume by the total bulk volume of the rock. There are different types of porosity depending on when and how the pore space was formed. Porosity can be measured directly using core samples in a lab or indirectly using well logging tools. An example calculation is provided to illustrate determining porosity from measurements of a rock core sample's dimensions and vacuumed pore volume.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
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2. Porosity
• Porosity is a measure of the storage capacity
of a reservoir. It is defined as the ratio of pore
volume to bulk volume, and it may be
expressed as either a percent or a fraction.
• In equation form, Porosity, φ, is given as
•
3. Porosity
• Total porosity and effective porosity
• Total porosity is the ratio of all pore spaces to the bulk volume of rock
• Effective porosity is the ratio of interconnected void spaces to the bulk volume
of the rock
• Only effective porosity contains fluids that can be produced from a well
• For granular rocks like sand stone the effective porosity approaches total
porosity
• For some limestone and cemented rocks there is large variation from effective
to total porosity
• There two types of porosity classified based on origination, the primary and
secondary.
• Primary porosity is caused during the original deposition of sediment.
Secondary porosity is cause by geological process like ground stresses, water
movement, other geological activities.
• For uniform grains the porosity in independent of their size. For cubic packing
the porosity is 47.6%, for rhombohedral packing it is 26%
• Porosity is depending on grain size distribution, grain arrangement, cementing
material quantity.
5. Rock porosity…..
• Petroleum explorenists sedimentary rock’s stratigraphy and
sedimentology to conclude the possibility for the existence of
petroleum system
• Then a decision is taken on drilling and well completion
• Significant part is to estimate the possible quantity of crude oil
• Reservoir characteristic is determined through a study of rock
properties
• Sedimentary rocks are made up of sandstone (quartz sand),
carbonate mud or dolomite. Dolomite reservoirs are good one
compared limestone as porosity is better in the former type.
• Sandstone rocks are composed of silica grains with minimal
fragmented particles.
• Carbonate rocks are made up of fossils of non even size.
6. Porosity ….
• Porosity gives the information on the capacity of
reservoirs to contain fluids
• The primary porosity (formed during original
sedimentation) has two types, inter and intra particle.
Inter particle porosity is lost through cementing. Intra
particle porosity is created by carbonate interiors
• Secondary porosity which was formed by geographical
processes can lead to dissolution porosity due to
carbonate dissolution and leaching. Another type of
secondary porosity is from fracture of rock leading to
less volume
8. Porosity and permeability
• Morphological porosity
– Caternary in which the pore open to more than one throat
passage
– Cul-de-sac in which the pore open to only one throat
passage
– Closed pore in which there is no connection with other
pores.
• Permeability is one ability for fluids to communicate
through porous medium
• Rock can be porous without being permeable
• Rock with permeability is suitable for fluid
accumulation
9. Pores-geographical processes
• The pores created during the initial sedimentation can under go changes
in the subsequent processes due to weight and dissolution.
• The weight from added top sediment can press the pores which may get
closed or some may get isolated
• This secondary process alter pore space and fuid flow through pores. The
fluid that was trapped in the closed pores cannot be produced.
• The brine that flow through the rock can plug the pores by cementing
grain to grain contact area.
• Sometimes the cation exchange can take place. The calcium ion from lime
may get replaced by Mg. this usually results in the space reduction thus
increasing available pores.
11. Pore volume –contributory factors
• Factors effecting pore volume:
– Grain size and packing pattern
– Shape of the grains: spherical grains makes good
packing thus reduce pore volume.
– Size of gains: uniformity in size causes uniformity
in pore volume
– Compaction causes reduction in volume.
Sandstone is less compressive compared to clay
12. Measurement-porosity
• Sample collection: core sample may be collected during drilling from
known depths
• Small samples called core plugs are cut from the core sample
• Samples are then cleaned using solvents to remove oil and water present
in the sample
• Bulk volume is the sum of grain volume and pore volume
• Bulk volume, Vb = Vg +Vp where Vg is grain volume and Vp is pore volume
• Absolute Porosity, φ, = Vp / Vb
13. Porosity-bulk volume measurement
• Cylindrical core sample is cut out with cross sectional area, Ac and length, L
• Volume is Ac*L
• For irregular sample use a water displacement method
• The sample is weighed initially and coated with wax and again weighed. Note
down both weights
• Take certain volume of solvent in a graduated glass cylinder. The volume of solvent
should be enough to submerge the sample. Note the volume . Now hang the
sample in the glass cylinder as shown in (a) so that the sample submerge in the
solvent without any adhered air bubbles. Note down the volume on the cylinder.
The difference in volume from the initial one gives the physical volume of the
sample.
• The wax coating volume should be subtracted from above noted volume to get the
bulk volume ( wax coating volume = coating weight /wax density)
15. Porosity calculation
• If the rock is made of uniform grain like quartz
then grain volume is
• Vg = mass of core sample/density of the mineral (core sample)
• For core with unknown mineral, an uncoated core sample in immersed in
suitable solvent as before for sufficient time so that all the pores are filled
with solvent. Now note down the volume on the cylinder. The difference
from initial volume gives the grain volume (Vg)
• Knowing both bulk volume and grain volume, then porosity may be
calculated
16. Pore measurement
• Measuring pore directly gives more accurate porosity value
• The cleaned and dried core sample is weighed and placed in a vacuum
flask as shown for a few hours
• Now introduce water slowly until the sample is completely submerged in
water.
• Now take out sample and shake the sample to remove outside water and
weigh quickly.
• Increase in mass is the weight of water taken up by pores. The water
weight may be converted to volume of water which is the pore volume
• Porosity, φ = pore volume/bulk volume
18. Porosity -indirect method
• Porosity can be measured indirectly using well logs. Sonic (acoustic) log is
one such method.
• The instrument sonde generates sound waves which travel in the vicinity
of well bore and their return time is noted
• Travel time (generation time and return detection time) is recorded with
depth of reservoir.
• Travel time is related to porosity by the equation:
19. Formation density log
• Another logging sonde that emits gamma rays
is used to compute bulk density of the
reservoir.
• This bulk density value is related to porosity:
20. Compressibility
• It is the shrinkage of a unit volume of substance per unit
increase in pressure
•Minus sign is added to give a positive compressibility value
• compressibility slightly vary with temperature
•All minerals found in sedimentary rocks are elastic in nature
21. Compressibility
• Reservoir rocks are subjected to overburden pressure from all rocks strata
above it
• Also the fluids in the pore exert pressure on the grains. This pore pressure
in independent of the overburden pressure. The pore pressure is the
atmospheric pressure allowing air to move within cavities.
• An increase in overburden pressure causes compaction in pore volume.
• The porosity measured in lab is independent of this overburden pressure.
So a correction is introduced to lab value while considering for reservoir:
• Porosity Correction: Δφ = - cp φlab ΔP o b, net
• ΔP o b, net is the net overburden pressure; φlab is the porosity result from
lab test; cp is the pore volume compressibility
22. Compressibility measurement
• Pore volume compressibility is measured in the lab by measuring variation
in pore volume at different conditions of overburden pressure (Pob) and
pore pressure (Pp)
• Pore volume is measured first at atmospheric pressure and reservoir
temperature
• The saturated sample is loaded to a core holder which is a device where
different combinations of Pob and Pp can be applied.
• The liquid that is squeezed out at each combination these two pressure
values are collected and measured the volume. Use these values to
compute current porosity values.
• Now plot φ against each Pob
• The graph is given below
25. Application of rock compressibility
• Rock compressibility is used to correct the lab measured porosity
• Production rate of a well suddenly changes with pressure over a period of
time. The results are interpreted using compressibility values
• Total reserves in a well is calculated using pore pressure and production
data. The pore volume of the reservoir changes as Pp decreases with
production, and cp is needed to correct the pore volume from its initial
value.
26. Fluid saturation
• The pores of the reservoir rock is partially
filled with water and hydrocarbon which can
be in the gas, liquid and solid state
• The saturation level of the fluid is given by:
27. Variation in fluid saturation
• Saturation level of the fluid in the rock helps the explorers to estimate
available oil in the reservoir.
• The saturation level never remains constant. When the oil is pumped out
the space left is taken up by water. When pressure drops the dissolved gas
get released and occupy the space. If gas is injected to the reservoir then
gas saturation occurs. So it is necessary to measure the level of all fluids
periodically.
• Measurement of fluid:
• The fluid in a core rock sample is extracted and individual volume
determined.
• The weighed core sample is placed in the thimble of the extraction unit
and heated. The solvent evaporates carries along with it the fluid in the
core sample and get condensed in the receiver flask.
30. Resistivity -measurement
• Rock materials are having high resistivity, also crude oil and natural gas
• Water which present along with crude oil is saline and having low
resistivity
• This difference is used to study the presence of crude oil in the rock
• In the above resistivity measuring sample holder fill with saline water the
resistivity will come down
• If some water is replaced with crude oil, the resistivity will go up.
• By varying water and crude oil quantity in the sample holder a series of
resistivity value are determined. Plot the values against percentage of
crude oil in the mixture and construct a graph. This graph is applicable to
that particular sample only.
31. Resistivity-porosity relation
• Let Rw (Ωm) is the resistivity of reservoir water, Ro (Ωm) is the resistivity of
reservoir rock saturated with reservoir water and Rt (Ωm) the resistivity of
reservoir rock saturated with oil and water
• Defining the formation factor as F= Ro/ R w
• F is related to porosity by the expression:
• For sand stone the value for C= 0.62 and m=2.15
• Now oil saturation expression is given by Sw
n = C φ –m R w / R t
• This expression is used for the calculation of oil saturation in the reservoir
rocks
32. Resistivity-porosity relation
• When resistivity sonde is sent into a reservoir to measure the resistivity
with depth of reservoir a typical graph as shown is obtained. High oil zones
show large resistivity while water zones show low resistivity.
33. Resistivity-porosity relation
• Mathematical calculation: for the above reservoir the water resistivity is
1.2Ωm, saturation exponent m=2.2, estimating the oil saturation at the
depth 4226ft where porosity is 24%
• Sw
n = C φ –m Rw / Rt
• Sw
2.2 = 0.62 (0.24) –2.15 x 1.2 / 400 = 0.04
• S w = 0.232 = 23.2%
• So = 100-23.2 = 76.8%
• At the depth 4226ft the oil saturation is 76.8%
34. Rock permeability
• Permeability is defined as the ability of a porous medium, e.g.,
sedimentary rock, to conduct fluids. The larger the permeability, the more
fluid flow can be achieved through the medium for a given set of
conditions. Darcy relationship:
• K is the coefficient of permeability (called simply as Permeability),
regardless of dimensions
35. • Permeability is given a dimension with the following definition
• If 1 atmosphere of pressure drop is required to flow a liquid of 1 cp
viscosity through a porous medium of 1 cm length and 1 cm2 cross-
sectional area at a rate of 1 cm3 per second, then the medium has a
permeability of 1 darcy.
• 1 darcy = 9.869 x 10-9 cm2.
• A more common unit of reservoir rock permeability is the millidarcy (md),
which is one thousandth of a darcy. Since the petroleum industry still uses
the system of field units, a conversion factor is introduced in Darcy’s law as
follows
• where q, k, A, ΔP, μ and L are in bbl/day, darcy, ft2, psi, cp and ft,
respectively.
36. Rock permeability and Darcy law
• The generalized differential form of Darcy’s
law is given below:
• ρ : density of the fluid, g/cm3
– g : gravitational acceleration (980 cm/s2)
– d : depth measured from a reference horizon, cm
37. Permeability measurement
• Laboratory measurement is performed under steady-state conditions
using a permeameter.
• The clean and dry core sample is mounted in the core holder and then
placed under a suitable confining pressure to simulate reservoir
overburden conditions.
• The sample is then placed under vacuum for a sufficient period of time to
remove all air from the sample.
• The fluid – usually brine, oil or air – is then flowed through the sample
until steady-state flow is established.
• The flow rate and the inlet pressure are then recorded
• the test is usually repeated at different sets of flow rate and inlet pressure
and the data is plotted
• The slope of the straight line is the core sample’s permeability multiplied
by A/ μL.
40. Permeability calculation
• Compute the permeability of the core sample whose flow data is shown in
above graph if the sample is 5 cm in diameter and 10 cm long. The fluid
used in the experiment is an oil with a viscosity of 1.6 cp.
• The cross-sectional area of the sample is , A = [π(5)2]/4= 19.63 cm2
• The slope of the best-fit line, m, is 6.25 cm3/min/atm, or 0.1 cm3/s/atm.
The core permeability is: k = m μ L / A = 0.1 x 1.6 x 10 / 19.63 = 0.0815 d
• = 81.5 md
This method of measurement needs some precautions
• If the sample is sandstone which contains some clay particles, distilled
water should not be used
• The flow rate should be low as the law does not work for excessive flow
• Inlet pressure should not be closed to confining pressure otherwise the
flow can bypass the sample
• If gas is used mean pressure (average of inlet and outlet) should be used
for plotting
41. Permeability and porosity
• For clean sandstone the permeability is related to porosity, k = a φ b
• If some clay particles are present in sandstone then a correction factor is
added
• k = a φ b (1-Vsh)c
• For carbonate rocks (calcite, dolomite, gypsum) such correlation not found
• Mineral deposits have minor effect on permeability
• Minute fractures improve permeability but no effect on porosity
42. Linear flow from Darcy law
• For incompressible fluid (no change in density with pressure) assume flow
direction along the x direction Darcy equation changes to:
• Rearranging the pressure at any location in the x direction is given by: