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Mohamed A. Kassab - One of the best experts on this subject based on the ideXlab platform.
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Petrographic and petrophysical characterization of some Paleozoic rocks, Um Bogma area, Southwest Sinai, Egypt
Egyptian Journal of Petroleum, 2018Co-Authors: Mohamed A. Kassab, Nader H. El Gendy, Shadia A.m. Saad, Mamdouh G. Shehata, Mohamed M. Gadallah, Mariline W. BadaroAbstract:Abstract Sixty-two samples were collected from the five Formations at Um Bogma area, (Southwest Sinai, Egypt). Nine samples were collected from Sarabit El Khedim Formation, ten samples were collected from Abu Hamata Formation, eighteen samples were collected from Adedia Formation, eight samples were collected from Um Bogma Formation and eighteen samples were collected from Abu Thora Formation. The Paleozoic rocks at Um Bogma area, consist mainly of sandstones, siltstones, shales, limestone and dolostones, which are unconformably overlie igneous and metamorphic rocks (granite, diorite and gneiss) of Precambrian age. The petrographic studies were applied to identify different rock units, different facies and its diagenetic history and to reveal its effect on the storage capacity properties. Different types of porosity (oversized, intergranular, fracture and vuggy porosities) have been identified based on the petrographic investigation of the studied thin sections. The Paleozoic sandstone rock samples are characterized by porosity average about 19% for Facies 1 (quartz wack) and about 18%for Facies 2 (quartz arenite) and permeability average 420 mD for Facies 1 (quartz wack) and 690 mD for Facies 2 (quartz arenite), so these rocks can be considered as good reservoir rocks. The Paleozoic carbonate rock samples (Facies 3) are characterized by poor porosity (less than 7%) and very low permeability (less than 0.5 mD), which caused by matrix and diagenetic processes and refer to bad reservoir rocks. Porosity can be linked to the two derived electrical properties (Formation Resistivity Factor and electrical tortuosity) of the studied Paleozoic rocks at Um Bogma area. The electrical tortuosity has significant effects on both permeability and Formation Resistivity Factor. The permeability decreases with increasing electrical tortuosity and the relation between both of them is inverse relationship with good coefficient of correlation. The permeability decreases with increasing electrical tortuosity and the relations between both of them are inverse relationships with high coefficient of correlation. The Formation Resistivity Factor increases with increasing electrical tortuosity and the relations between both of them are positive relationships with a fair to very high coefficient of correlation.
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Petrographic and petrophysical characterization of some Paleozoic rocks, Um Bogma area, Southwest Sinai, Egypt
Elsevier, 2018Co-Authors: Mohamed A. Kassab, Shadia A.m. Saad, Mamdouh G. Shehata, Mohamed M. Gadallah, Nader El H. Gendy, Mariline W. BadaroAbstract:Sixty-two samples were collected from the five Formations at Um Bogma area, (Southwest Sinai, Egypt). Nine samples were collected from Sarabit El Khedim Formation, ten samples were collected from Abu Hamata Formation, eighteen samples were collected from Adedia Formation, eight samples were collected from Um Bogma Formation and eighteen samples were collected from Abu Thora Formation.The Paleozoic rocks at Um Bogma area, consist mainly of sandstones, siltstones, shales, limestone and dolostones, which are unconformably overlie igneous and metamorphic rocks (granite, diorite and gneiss) of Precambrian age.The petrographic studies were applied to identify different rock units, different facies and its diagenetic history and to reveal its effect on the storage capacity properties. Different types of porosity (oversized, intergranular, fracture and vuggy porosities) have been identified based on the petrographic investigation of the studied thin sections.The Paleozoic sandstone rock samples are characterized by porosity average about 19% for Facies 1 (quartz wack) and about 18%for Facies 2 (quartz arenite) and permeability average 420 mD for Facies 1 (quartz wack) and 690 mD for Facies 2 (quartz arenite), so these rocks can be considered as good reservoir rocks. The Paleozoic carbonate rock samples (Facies 3) are characterized by poor porosity (less than 7%) and very low permeability (less than 0.5 mD), which caused by matrix and diagenetic processes and refer to bad reservoir rocks.Porosity can be linked to the two derived electrical properties (Formation Resistivity Factor and electrical tortuosity) of the studied Paleozoic rocks at Um Bogma area. The electrical tortuosity has significant effects on both permeability and Formation Resistivity Factor. The permeability decreases with increasing electrical tortuosity and the relation between both of them is inverse relationship with good coefficient of correlation. The permeability decreases with increasing electrical tortuosity and the relations between both of them are inverse relationships with high coefficient of correlation. The Formation Resistivity Factor increases with increasing electrical tortuosity and the relations between both of them are positive relationships with a fair to very high coefficient of correlation. Keywords: Paleozoic, Porosity, Permeability, Electrical properties, Um Bogma, Egyp
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Integrated petrographical and petrophysical studies of some Eocene carbonate rocks, Southwest Sinai, Egypt
Egyptian Journal of Petroleum, 2015Co-Authors: Hesham Abuseda, Mohamed A. Kassab, Amir Maher Sayed Lala, Nahla A. El SayedAbstract:Abstract The present study deals with the effect of petrographical aspects on the petrophysical properties of the Eocene rocks, which are represented by Thebes, Samalut, Darat and Tanka Formations in Southwest Sinai, Egypt. The studied diagenetic Factors have an important role to enhance and/or reduce the pore volume and governing the petrophysical behavior. The cementation and neomorphism are the main porosity-reducing Factors, whereas dissolution and leaching out as well as the fossil content are the main porosity-enhancing Factors. The petrophysical behavior of the studied facies has been outlined by measuring rock porosity, density, permeability, and electrical Resistivity. The reservoir quality index (RQI) reveals that, the petrophysical features of the studied facies are consistent with the petrographical characteristics indicating bad reservoir properties for Thebes, Samalut, Darat and Tanka Formations in the nearby subsurface extensions. Studying the petrophysical behavior indicates that, both permeability and Formation Resistivity Factor are mostly dependent on the effective porosity and to some extent on the electric tortuosity.
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Reservoir characterization of the Lower Abu Madi Formation using core analysis data: El-Wastani gas field, Egypt
Journal of African Earth Sciences, 2015Co-Authors: Mohamed A. Kassab, Mostafa A. Teama, Burns A. Cheadle, Ezz S. El-din, Ibtehal F. Mohamed, Maher A. MesbahAbstract:The Messinian (Upper Miocene) sandstones of the Lower Abu Madi unit are the main reservoirs of the El-Wastani (EW) gas field, located in the onshore Nile Delta of Egypt. Reservoir quality is highly variable and represents the major risk in locating new delineation and development wells in the field. Four lithofacies (F1, F2, F3 and F4) are characterized based on textural attributes and sedimentary structures. Facies F4, which is a medium to coarse-grained fluvial channel sandstone, exhibits the best reservoir rock quality. Four hydraulic flow units (HFU 1 through HFU 4) were delineated in the studied wells with flow zone index (FZI) values indicative of a broad range of hydraulic properties. The cementation Factor (m) value, was calculated from the inverse relationship between porosity and Formation Factor for EW-4 and EW-6 wells, agrees with the published values of clean sandstone reservoirs. The results of grain density analyses is close to the published value of grain density of quartz, and also supported by the results of petrographic study, where quartz is the dominant framework mineral. Generally, both the permeability and porosity can be linked to the two derived electrical properties (Formation Resistivity Factor and electrical tortuosity) in the clastic reservoirs of the Lower Abu Madi unit. This correlation is particularly evident in the western and central parts of the study area at EW-4 and EW-6 wells, where facies F4 is dominant.
Hilmi S. Salem - One of the best experts on this subject based on the ideXlab platform.
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Relationships Among Formation Resistivity Factor, Compressional Wave Velocity, and Porosity for Reservoirs Saturated with Multiphase Fluids
Energy Sources, 2001Co-Authors: Hilmi S. SalemAbstract:The electric Formation Resistivity Factor (F) and the seismic compressional wave velocity (v p) are powerful parameters in understanding the electric and elastic behavior of porous media and in identifying the type of fluid saturating the pore spaces. The Formation Resistivity Factor is a function of various influences, including pore and grain properties; saturation, salinity, and viscosity of pore water; Formation and pore-water resistivities; cation-exchange capacity; and clay content. The compressional wave velocity is a function of bulk (grain and fluid) density; type of saturant and degree of saturation; and various elastic moduli, including bulk (pore, fluid, and grain) compressibility. Both parameters (F and v p) are significantly affected by variations of porosity ( φ ), pressure, and temperature. The three parameters (F, v p, φ) were obtained from well log measurements for complex, heterogeneous, and consolidated shaly sandstone reservoirs, saturated with multiphase fluids, offshore of the easte...
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Determination of porosity, Formation Resistivity Factor, Archie cementation Factor, and pore geometry Factor for a glacial aquifer
Energy Sources, 2001Co-Authors: Hilmi S. SalemAbstract:Porosity (o), Formation Resistivity Factor (F), Archie cementation Factor (m), and pore geometry Factor (a) have strong influences on the processes of electric-current conduction through saturated porous media. In the present study, these parameters were determined from electric Resistivity measurements, along with grain size and water analyses, for a fresh-water aquifer in northern Germany. The aquifer is composed of glacial deposits consisting of silts, sands, and gravels, with a majority of sands and a small amount of clays. The o and F exhibit, respectively, values ranging from 25% to 51% and from 4 to 16, for which a range of 1.64-2.05 was obtained for m, and a value of 1.25 was obtained for a. An inverse relationship between o and F, with a coefficient of correlation of 0.95, was also obtained.
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The Influence of Clay Conductivity on Electric Measurements of Glacial Aquifers
Energy Sources, 2001Co-Authors: Hilmi S. SalemAbstract:The conductivities of pore water and clays are important mechanisms in the process of electric-current conduction through porous media. The clay conductivity contributes effectively to the process of electric-current conduction, particularly when the medium is saturated with fresh water. In the present study, the conductivity of clays was investigated in relation to the Formation Resistivity Factor and specific surface area. The Formation Resistivity Factor is an important parameter in defining variations of the Formation and pore-water resistivities. The apparent and intrinsic Formation Resistivity Factors, along with other petrophysical and hydrophysical parameters, were determined from surface electric measurements and analyses of sediments and water samples for a glacial aquifer (northern Germany). The aquifer is saturated with fresh water and composed of unconsolidated sediments that consist primarily of silts, sands, and gravels, with a majority of sands and a small amount of clays. The sediments of...
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Physical and Mathematical Aspects of Tortuosity in Regard to the Fluid Flow and Electric Current Conduction in Porous Media: Example of the Hibernia and Terra Nova Reservoirs, Off the Eastern Coast of Canada
Energy Sources, 2000Co-Authors: Hilmi S. Salem, George V. ChilingarianAbstract:Tortuosity tau is physically defined as the ratio (or the square of the ratio) of the effective length of pore channels (through which the hydraulic flow and electric current are conducted) to the length parallel to the overall direction of the pore channels in a porous medium. It has a significant influence on hydraulic flow and electric current because of its response to the variations in lithology, pressure and petrophysical properties. Determination of tortuosity enables one to understand the mechanisms of hydraulic flow and electric current, and the channel-network com plexities in porous media. In this study, physical and mathematical aspects of tortuosity are discussed. Also, tortuosity is mathematically derived as the square root of the dimensionless Formation Resistivity Factor times fractional porosity. Tortuosity can be successfully used for interpretation of the physical behavior of unconsolidated and consolidated porous media, similarly, and for Formations characterized by high degrees of com...
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Determination of specific surface area and mean grain size from well-log data and their influence on the physical behavior of offshore reservoirs
Journal of Petroleum Science and Engineering, 1999Co-Authors: Hilmi S. Salem, George V. ChilingarianAbstract:Abstract Specific surface area (ss) is one of the most important and effective geometrical parameters in defining and interpreting petrophysical relationships, textural framework, and fluid–solid interactions in porous media. It is defined as the interstitial surface area of the pores and pore channels for each unit of bulk volume, grain volume, or pore volume, or for a unit of weight of a material. Variations in the specific surface area (ss) and mean grain size (Gs) influence the physical parameters controlling electric current and hydraulic flow, as well as acoustic and seismic wave propagation and attenuation. In this study, the specific surface area per unit of pore volume (sp) and the mean grain size (Gs) were numerically determined from well-log data for 14 wells penetrating the Hibernia and Terra Nova reservoirs of the Jeanne d'Arc Basin (JDB), offshore Newfoundland, Canada. Both parameters (sp and Gs) were derived using the Formation Resistivity Factor, porosity, and permeability. Mathematical and physical concepts of ss (including sp) and Gs were analyzed, and empirical equations linking sp and Gs with various petrophysical parameters were obtained. The lithological components (shale, sandstone, silt, limestone, and marl) were also obtained. The rocks in both reservoirs are generally characterized by fine- to medium grain size and high values of sp.
Bassem S. Nabawy - One of the best experts on this subject based on the ideXlab platform.
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Impacts of the petrophysical and diagenetic aspects on the geomechanical properties of the dolomitic sequence of Gebel El-Halal, Sinai, Egypt
Bulletin of Engineering Geology and the Environment, 2019Co-Authors: Bassem S. Nabawy, Ahmed Abd AalAbstract:The aim of this paper is to demonstrate the controlling effect of the mineral composition, the diagenetic history and the petrophysical properties on the geomechanical properties and durability of the dolomitic El-Halal Formation in its type section in North Sinai as well as its economic potential for construction purposes. The petrographic studies include descriptions of both the mineral composition and diagenetic processes, while the petrophysical studies measure the density, porosity, permeability and true Formation Resistivity Factor. In addition, some geomechanical laboratory tests were conducted, including the petrographic description of the mineral composition and diagenetic processes, as well as the Schmidt Hammer number (SHV), point load index (IS_50), uniaxial compressive strength (UCS), and ultrasonic longitudinal wave velocity measurements. Scanning electron microscopy was used to help in pore-type description (intergranular, vuggy, etc.). Based on lithologic changes and mineral composition, the El-Halal Formation can be subdivided into three informal members: (1) lower dolomitic limestone, (2) middle sandy dolostone and (3) upper dolostone member. Petrographically, the sequence consists of three dominant microfacies: (1) dolomitic mudstone microfacies (dolomitic micrite to dolomicrite), (2) dolowackestone (clayey to sandy dolomicrite), and (3) dolomudstone microfacies (dolosparite). The most diagnostic diagenetic processes are dolomitization, cementation by calcite, aggrading neomorphism and the creation of authigenic illite. In the study area, dolomitization has affected almost all the Cenomanian succession. The SHV, IS_50, and UCS values of the samples indicate high-strength rocks. The present study indicates the dependence of the geomechanical properties on the petrophysical properties and the mineral composition of the studied rocks. Modeling the properties indicates a reliable correlation between the different parameters which can be applied for predicting and characterizing the dolomitic El-Halal Formation elsewhere. The results of the present investigation are useful for studying the geomechanical and petrophysical properties of similar dolomitic sequences and in ranking its potential as construction materials.
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Impacts of fossil anisotropy on the electric and permeability anisotropy of highly fossiliferous limestone: a case study
Marine Geophysical Research, 2018Co-Authors: Bassem S. NabawyAbstract:The Middle Eocene Lutetian Samalut Formation is among the best examples of anisotropic fossiliferous rocks in Egypt, where the effect of the anisotropic Nummulite Gizehensis fossils on the petrophysical behavior can be traced. The Samalut Formation has been sampled and studied at Wadi Feiran in SW Sinai. Petrographically, it is composed of two microfacies; Nummulitic packstone and Fusulinid mudstone. Tight cementation by micro to pseudosparite, aggrading neomorphism and compaction with increasing load pressure are the most important porosity-reducing Factors. The anisotropy of the fossil content (λ_F), due to shape and orientation, and its effect on the petrophysical properties were assigned by measuring the lengths of the longest and shortest axes. Petrophysically, both microfacies are characterized by low porosity values (1.47 ≤ $${\emptyset _{{\text{He}}}}$$ ∅ He ≤ 5.29%). The Formation Resistivity Factor (F) and permeability (k) were measured in the horizontal and vertical directions (parallel and perpendicular to the bedding plane, respectively). The studied samples are characterized by high to very high Formation Resistivity Factor (190 ≤ F ≤ 8938) and relatively very low permeability (0.012 ≤ k ≤ 0.110 md). The studied samples are characterized by fair to medium electric anisotropy ‘λ_E’, which is attributed to a relatively medium to fair degree of electric foliation. It has been shown that, the fossil shape anisotropy and orientation ‘λ_F’ (1.5 ≤ λ_F ≤ 3.5) is the main contributor for the electric and permeability anisotropy that corrected for the same porosity value (1.61 ≤ λ_EC ≤ 2.25 and 1.03 ≤ λ_kC ≤ 2.04; respectively). Foliation of the studied microfacies has been contributed to the orientation of the fossil remains parallel to the bedding plane. The anisotropy degree is relatively greater for the Nummulitic packstone microfacies than that of the Fusulinid mudstone. The present study refers to the possible anisotropic effect of fossil content (due to shape and orientation) on the petrophysical properties of the studied rocks which may be extended to the anisotropy of reservoir rocks on the bedding scale.
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Determining the porosity exponent m and lithology Factor a for sandstones and their control by overburden pressure: A case study from the Gulf of Suez, Egypt
AAPG Bulletin, 2018Co-Authors: Mohamed S. El Sharawy, Bassem S. NabawyAbstract:The porosity exponent m represents an important parameter in Archie’s equation; it is routinely used in well logging interpretation and Formation evaluation. It reflects some petrophysical rock properties, such as the petrofabrics, pore fabrics, and overburden pressure (OBP). Data measured at ambient conditions for a total of 55 sandstone core samples were obtained from 8 wells varying in depositional facies, geologic age, degree of consolidation, and cementation material and then measured again at OBP, similar to the actual reservoir conditions, to check the effect of OBP on Archie’s parameters and to introduce a model of high reliability. Other published data sets were also used to confirm the study results. Based on the best-fit regression analysis, several empirical relationships were introduced to relate the porosity exponent to pore volume, lithology Factor, and permeability. The effect of OBP on the porosity exponent was also investigated in relation to the petrophysical parameters. Given the above, a new statistical model is proposed to relate the porosity exponent to the permeability of the studied sandstone samples in the Gulf of Suez, Egypt. The effect of confining pressure on the studied porosity exponent m and the lithology Factor a is significant when porosity φ is less than or equal to 10%. From the present study, categorization of the studied samples into flow units and rock types using the hydraulic flow unit and the discrete rock types increased the reliability of the obtained relationships and increased the applicability of the obtained equations. In addition, the value of the lithology Factor a fluctuates around 1 (0.92–1.04, regardless of the applied processing method), whereas the value of the porosity exponent m fluctuates around 1.83. The obtained relationships between the Formation Resistivity Factor and porosity have a very high reliability (−0.949 ≥ correlation coefficient ≥ −0.969).
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Impacts of fossil anisotropy on the electric and permeability anisotropy of highly fossiliferous limestone: a case study
Marine Geophysical Research, 2017Co-Authors: Bassem S. NabawyAbstract:The Middle Eocene Lutetian Samalut Formation is among the best examples of anisotropic fossiliferous rocks in Egypt, where the effect of the anisotropic Nummulite Gizehensis fossils on the petrophysical behavior can be traced. The Samalut Formation has been sampled and studied at Wadi Feiran in SW Sinai. Petrographically, it is composed of two microfacies; Nummulitic packstone and Fusulinid mudstone. Tight cementation by micro to pseudosparite, aggrading neomorphism and compaction with increasing load pressure are the most important porosity-reducing Factors. The anisotropy of the fossil content (λF), due to shape and orientation, and its effect on the petrophysical properties were assigned by measuring the lengths of the longest and shortest axes. Petrophysically, both microfacies are characterized by low porosity values (1.47 ≤ $${\emptyset _{{\text{He}}}}$$ ≤ 5.29%). The Formation Resistivity Factor (F) and permeability (k) were measured in the horizontal and vertical directions (parallel and perpendicular to the bedding plane, respectively). The studied samples are characterized by high to very high Formation Resistivity Factor (190 ≤ F ≤ 8938) and relatively very low permeability (0.012 ≤ k ≤ 0.110 md). The studied samples are characterized by fair to medium electric anisotropy ‘λE’, which is attributed to a relatively medium to fair degree of electric foliation. It has been shown that, the fossil shape anisotropy and orientation ‘λF’ (1.5 ≤ λF ≤ 3.5) is the main contributor for the electric and permeability anisotropy that corrected for the same porosity value (1.61 ≤ λEC ≤ 2.25 and 1.03 ≤ λkC ≤ 2.04; respectively). Foliation of the studied microfacies has been contributed to the orientation of the fossil remains parallel to the bedding plane. The anisotropy degree is relatively greater for the Nummulitic packstone microfacies than that of the Fusulinid mudstone. The present study refers to the possible anisotropic effect of fossil content (due to shape and orientation) on the petrophysical properties of the studied rocks which may be extended to the anisotropy of reservoir rocks on the bedding scale.
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Effect of the mineralogical composition on the petrophysical behavior of the amygdaloidal and vesicular basalt of Wadi Wizr, Eastern Desert, Egypt
Journal of African Earth Sciences, 2017Co-Authors: Bassem S. Nabawy, Nadia A. WassifAbstract:Abstract This paper gives an account of the petrophysical characteristics and the petrographical descriptions of Tertiary vesicular and amygdaloidal olivine basalt flows from Wadi Wizr in the central Eastern Desert of Egypt. The petrographical studies indicated that the studied vesicular basalts are rich in calcic-plagioclase, augite and olivine in addition to numerous amounts of fine opaque minerals and vesicles filled with carbonate and quartz amygdales. The degree of oxidation and alteration of magnetite and ilmenite are discussed in detail. Petrophysically, the studied samples can be grouped into two main groups; the first group includes amygdaloidal basalts and the second group consists of vesicular basalts. The vesicular group (the permeable one) is characterized by fair to very good porosity (∅), good permeability (k), very low true Formation Resistivity Factor (F) and contain micro to ultra micropores. On the other hand, the amygdaloidal basalt group (impermeable group) is characterized by very low storage capacity properties, fair porosity, negligible permeability, medium to high true Formation Resistivity Factor and ultra micropores. The mercury injection capillary pressure technique (MICP) indicates that the pore throats of the studied vesicular samples have a binomial distribution (rank IV), while that of the amygdaloidal samples have a trinomial distribution (rank V). It has been found in this study that the petrophysical behavior of basalts is dependent on the degree of oxidation and alteration; and in particular on the rate of cooling and oxidation of the opaque minerals which caused filling in the primarily produced vesicles by low temperature secondary minerals.
Mariline W. Badaro - One of the best experts on this subject based on the ideXlab platform.
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Petrographic and petrophysical characterization of some Paleozoic rocks, Um Bogma area, Southwest Sinai, Egypt
Egyptian Journal of Petroleum, 2018Co-Authors: Mohamed A. Kassab, Nader H. El Gendy, Shadia A.m. Saad, Mamdouh G. Shehata, Mohamed M. Gadallah, Mariline W. BadaroAbstract:Abstract Sixty-two samples were collected from the five Formations at Um Bogma area, (Southwest Sinai, Egypt). Nine samples were collected from Sarabit El Khedim Formation, ten samples were collected from Abu Hamata Formation, eighteen samples were collected from Adedia Formation, eight samples were collected from Um Bogma Formation and eighteen samples were collected from Abu Thora Formation. The Paleozoic rocks at Um Bogma area, consist mainly of sandstones, siltstones, shales, limestone and dolostones, which are unconformably overlie igneous and metamorphic rocks (granite, diorite and gneiss) of Precambrian age. The petrographic studies were applied to identify different rock units, different facies and its diagenetic history and to reveal its effect on the storage capacity properties. Different types of porosity (oversized, intergranular, fracture and vuggy porosities) have been identified based on the petrographic investigation of the studied thin sections. The Paleozoic sandstone rock samples are characterized by porosity average about 19% for Facies 1 (quartz wack) and about 18%for Facies 2 (quartz arenite) and permeability average 420 mD for Facies 1 (quartz wack) and 690 mD for Facies 2 (quartz arenite), so these rocks can be considered as good reservoir rocks. The Paleozoic carbonate rock samples (Facies 3) are characterized by poor porosity (less than 7%) and very low permeability (less than 0.5 mD), which caused by matrix and diagenetic processes and refer to bad reservoir rocks. Porosity can be linked to the two derived electrical properties (Formation Resistivity Factor and electrical tortuosity) of the studied Paleozoic rocks at Um Bogma area. The electrical tortuosity has significant effects on both permeability and Formation Resistivity Factor. The permeability decreases with increasing electrical tortuosity and the relation between both of them is inverse relationship with good coefficient of correlation. The permeability decreases with increasing electrical tortuosity and the relations between both of them are inverse relationships with high coefficient of correlation. The Formation Resistivity Factor increases with increasing electrical tortuosity and the relations between both of them are positive relationships with a fair to very high coefficient of correlation.
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Petrographic and petrophysical characterization of some Paleozoic rocks, Um Bogma area, Southwest Sinai, Egypt
Elsevier, 2018Co-Authors: Mohamed A. Kassab, Shadia A.m. Saad, Mamdouh G. Shehata, Mohamed M. Gadallah, Nader El H. Gendy, Mariline W. BadaroAbstract:Sixty-two samples were collected from the five Formations at Um Bogma area, (Southwest Sinai, Egypt). Nine samples were collected from Sarabit El Khedim Formation, ten samples were collected from Abu Hamata Formation, eighteen samples were collected from Adedia Formation, eight samples were collected from Um Bogma Formation and eighteen samples were collected from Abu Thora Formation.The Paleozoic rocks at Um Bogma area, consist mainly of sandstones, siltstones, shales, limestone and dolostones, which are unconformably overlie igneous and metamorphic rocks (granite, diorite and gneiss) of Precambrian age.The petrographic studies were applied to identify different rock units, different facies and its diagenetic history and to reveal its effect on the storage capacity properties. Different types of porosity (oversized, intergranular, fracture and vuggy porosities) have been identified based on the petrographic investigation of the studied thin sections.The Paleozoic sandstone rock samples are characterized by porosity average about 19% for Facies 1 (quartz wack) and about 18%for Facies 2 (quartz arenite) and permeability average 420 mD for Facies 1 (quartz wack) and 690 mD for Facies 2 (quartz arenite), so these rocks can be considered as good reservoir rocks. The Paleozoic carbonate rock samples (Facies 3) are characterized by poor porosity (less than 7%) and very low permeability (less than 0.5 mD), which caused by matrix and diagenetic processes and refer to bad reservoir rocks.Porosity can be linked to the two derived electrical properties (Formation Resistivity Factor and electrical tortuosity) of the studied Paleozoic rocks at Um Bogma area. The electrical tortuosity has significant effects on both permeability and Formation Resistivity Factor. The permeability decreases with increasing electrical tortuosity and the relation between both of them is inverse relationship with good coefficient of correlation. The permeability decreases with increasing electrical tortuosity and the relations between both of them are inverse relationships with high coefficient of correlation. The Formation Resistivity Factor increases with increasing electrical tortuosity and the relations between both of them are positive relationships with a fair to very high coefficient of correlation. Keywords: Paleozoic, Porosity, Permeability, Electrical properties, Um Bogma, Egyp
John Rogers Smith - One of the best experts on this subject based on the ideXlab platform.
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I-B Shaly Sand Model: Application to Hydrocarbon Detection
Journal of Canadian Petroleum Technology, 2007Co-Authors: G. Ipek, Zaki Bassiouni, B. Kurniawan, John Rogers SmithAbstract:Hydrocarbon bearing shaly Formations can be detected using cation exchange capacity (CEC) shaly sand models. Most CEC shaly sand models still depend on a laboratory measurement of the CEC value. In addition, these models use one value of Formation Resistivity Factor which is a function of the rocks's cementation exponent. Using one Formation Resistivity Factor in shaly sand reservoirs can result in overestimation of the water saturation, which in turn results in overlooking Formations with hydrocarbon potential. This paper introduces a new CEC shaly sand model, Ipek-Bassiouni (I-B), that improves the definition of the Formation Resistivity Factor used in shaly sand Formations. This model can also calculate the CEC value directly from the well log data. The Ipek-Bassiouni (I-B) Shaly Sand Model considers that an electric current follows two types of paths in shaly sand. One path represents current flow in free water, and another path represents current flow in bound water. The differentiation between these two paths is accomplished by using two different Formation Resistivity Factors in free water and bound water. The two Formation Resistivity Factors are expressed using two cementation exponents for free water and for bound water. The validity of the model was checked using the cation exchange capacity measured from core samples and drill cuttings. Calculated CEC values display a good agreement with the measured CEC values. The estimated water saturations from the model indicate better hydrocarbon detection in the zone of interest.
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I-B Shaly Sand Model: Application to Hydrocarbon Detection
Journal of Canadian Petroleum Technology, 2007Co-Authors: G. Ipek, B. Kurniawan, Z. Bassiouni, John Rogers SmithAbstract:Abstract Hydrocarbon bearing shaly Formations can be detected using cation exchange capacity (CEC) shaly sand models. Most CEC shaly sand models still depend on a laboratory measurement of the CEC value. In addition, these models use one value of Formation Resistivity Factor which is a function of the rocks's cementation exponent. Using one Formation Resistivity Factor in shaly sand reservoirs can result in overestimation of the water saturation, which in turn results in overlooking Formations with hydrocarbon potential. This paper introduces a new CEC shaly sand model, Ipek-Bassiouni (I-B), that improves the definition of the Formation Resistivity Factor used in shaly sand Formations. This model can also calculate the CEC value directly from the well log data. The Ipek-Bassiouni (I-B) Shaly Sand Model considers that an electric current follows two types of paths in shaly sand. One path represents current flow in free water, and another path represents current flow in bound water. The differentiation between these two paths is accomplished by using two different Formation Resistivity Factors in free water and bound water. The two Formation Resistivity Factors are expressed using two cementation exponents for free water and for bound water. The validity of the model was checked using the cation exchange capacity measured from core samples and drill cuttings. Calculated CEC values display a good agreement with the measured CEC values. The estimated water saturations from the model indicate better hydrocarbon detection in the zone of interest. Introduction Water saturation of hydrocarbon bearing shaly Formations can be determined using available CEC shaly sand models. Current CEC models are based on cation exchange capacity and the ionic double layer concept. However, the use of these models is impractical because most of the time CEC data is not usually available to the log analyst, hence; a laboratory measurement of CEC is required. Different laboratory techniques to measure this parameter are found to yield different CEC values for the same core sample. Previous researchers at Louisiana State University (LSU)(1–7) have developed a shaly sand interpretation technique, referred herein as the LSU model, based on log data such as Resistivity, spontaneous potential, neutron and density logs. This model is based on the Waxman and Smits(8) concept of supplementing water conductivity with clay counter ions conductivity. It also utilizes the dual water theory(9), which relates each conductivity term to a particular type of water, free and bound, each occupying a specific volume of the total pore space. The main assumption of the LSU model is that the counter ion conductivity is represented by a hypothetical sodium chlorite solution. The LSU model is a practical approach that represents the conductivity behaviour of shaly sand. However, same as all previous models, the LSU model also assumes that the electric current follows the same path in both free and bound water areas. This leads to the use of the same Formation Resistivity Factor to evaluate the shaly Formations. This assumption can cause hydrocarbon bearing shaly Formations to be overlooked due to overestimation of water saturation in the zone of interest.