To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected ...To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected and analyzed using N2 adsorption, high-pressure mercury injection capillary pressure(MICP), nuclear magnetic resonance(NMR), high-speed centrifugation, and displacement image techniques. The results show that shale pore structure characteristics control shale oil movability directly. Movable oil saturation has a positive relationship with pore volume for radius > 2 μm, as larger pores often have higher movable oil saturation, indicating that movable oil is present in relatively larger pores. The main reasons for this are as follows. The relatively smaller pores often have oil-wetting properties because of organic matter, which has an unfavorable effect on the flow of oil, while the relatively larger pores are often wetted by water, which is helpful to shale oil movability. The rich surface provided by the relatively smaller pores is beneficial to the adsorption of immovable oil. Meanwhile, the relatively larger pores create significant pore volume for movable oil. Moreover, the larger pores often have good pore connectivity. Pores and fractures are interconnected to form a complex fracture network, which provides a good permeability channel for shale oil flow. The smaller pores are mostly distributed separately;thus, they are not conducive to the flow of shale oil. The mineral composition and fabric macroscopically affect the movability of shale oil. Calcite plays an active role in shale oil movability by increasing the brittleness of shale and is more likely to form micro-cracks under the same stress background. Clay does not utilize shale oil flow because of its large specific surface area and its block effect. The bedding structure increases the large-scale storage space and improves the connectivity of pores at different scales, which is conducive to the movability of shale oil.展开更多
The glutenite in the fourth member of Shahejie Formation(Es^4) in northern Dongying depression straightforwardly penetrated into the muddy bathyal -abyss facies.The conditions of reservoir is very superior:(1) the hig...The glutenite in the fourth member of Shahejie Formation(Es^4) in northern Dongying depression straightforwardly penetrated into the muddy bathyal -abyss facies.The conditions of reservoir is very superior:(1) the high quality thick bedded oil source rock is developed very well in the Lijin sag and Minfeng sag of the study area,and it has the higher capability of generating hydrocarbon;(2) the展开更多
Based on anatomy of key areas and data points and analysis of typical features of shell layer in Guanyinqiao Member, basic characteristics of key interfaces, mainly bentonite layers, in the Upper Ordovician Wufeng For...Based on anatomy of key areas and data points and analysis of typical features of shell layer in Guanyinqiao Member, basic characteristics of key interfaces, mainly bentonite layers, in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in the Sichuan Basin and its surrounding areas and the relationship between these key interfaces with the deposition of organic-rich shale have been examined systematically. The Wufeng Formation-Longmaxi Formation has four types of marker beds with interface attributes, namely, the characteristic graptolite belt, Guanyinqiao Member shell layer, section with dense bentonite layers, and concretion section, which can be taken as key interfaces for stratigraphic division and correlation of the graptolite shale. The shell layer in Guanyinqiao Member is the most standard key interface in Wufeng Formation-Longmaxi Formation, and can also be regarded as an important indicator for judging the depositional scale of organic-rich shale in key areas. There are 8 dense bentonite sections of two types mainly occurring in 7 graptolite belts in these formations. They have similar interface characteristics with the shell layer in Guanyinqiao Member in thickness and natural gamma response, and belong to tectonic interfaces(i.e., event deposits). They have three kinds of distribution scales: whole region, large part of the region, and local part, and can be the third, fourth and fifth order sequence interfaces, and have a differential control effect on organic-rich shale deposits. The horizon the characteristic graptolite belt occurs first is the isochronous interface, which is not directly related to the deposition of organic-rich shale. Concretions only appear in local areas, and show poor stability in vertical and horizontal directions, and have no obvious relationship with the deposition of the organic-rich shale.展开更多
Based on 991 groups of analysis data of shale samples from the Lower Member of the Cretaceous Eagle Ford Formation of 1317 production wells and 72 systematic coring wells in the U.S. Gulf Basin, the estimated ultimate...Based on 991 groups of analysis data of shale samples from the Lower Member of the Cretaceous Eagle Ford Formation of 1317 production wells and 72 systematic coring wells in the U.S. Gulf Basin, the estimated ultimate recovery(EUR) of shale oil and gas of the wells are predicted by using two classical EUR estimation models, and the average values predicted excluding the effect of engineering factors are taken as the final EUR. Key geological factors controlling EUR of shale oil and gas are fully investigated. The reservoir capacity, resources, flow capacity and fracability are the four key geological parameters controlling EUR. The storage capacity of shale oil and gas is directly controlled by total porosity and hydrocarbon-bearing porosity, and indirectly controlled by total organic carbon(TOC) and vitrinite reflectance(Ro). The resources of shale oil and gas are controlled by hydrocarbon-bearing porosity and effective shale thickness etc. The flow capacity of shale oil and gas is controlled by effective permeability, crude oil density, gas-oil ratio, condensate oil-gas ratio, formation pressure gradient, and Ro. The fracability of shale is directly controlled by brittleness index, and indirectly controlled by clay content in volume. EUR of shale oil and gas is controlled by six geological parameters: it is positively correlated with effective shale thickness, TOC and fracture porosity, negatively correlated with clay content in volume, and increases firstly and then decreases with the rise of Ro and formation pressure gradient. Under the present upper limit of horizontal well fracturing effective thickness of 65 m and the lower limit of EUR of 3×10^(4) m^(3), when TOC<2.3%, or Ro<0.85%, or clay content in volume larger than 25%, and fractures and micro-fractures aren’t developed, favorable areas of shale oil and gas hardly occur.展开更多
Tight oil in the redeposited carbonates was mainly distributed in the Lower Submember of Member 3 of Shahejie Formation in Shulu sag of Jizhong depression,North China.Through high-resolution 3D seismic data,well loggi...Tight oil in the redeposited carbonates was mainly distributed in the Lower Submember of Member 3 of Shahejie Formation in Shulu sag of Jizhong depression,North China.Through high-resolution 3D seismic data,well logging data and drilling data,the Lower Submember of Member 3 of Shahejie Formation was divided into 5 third-order sequences and 15 parasequence sets.The redeposited marl and rudstone were major reserving horizons of tight oil,and ten reserving space types were developed and could be classified into two main categories,i.e.,pores and fractures.Two types of tight oil reservoirs were established,i.e.,the marl hydrocarbon reservoir of the source-reservoir integration and the rudstone hydrocarbon reservoirs of the source-reservoir paragenesis.The assemblage relationship among the high-quality source rocks,system tracts with the source-reservoir configuration was the major control factor for tight oil accumulation in the redeposited carbonates.The lacustrine transgressive system tracts and highstand systems tracts in SQ1 to SQ5 were the favorable horizons for development of the marl hydrocarbon reservoir,the lowstand system tracts in SQ1 to SQ3 were the favorable horizons for development of the rudstone hydrocarbon reservoir.展开更多
In the continental lake basin whose structures were extraordinarily active, tectonism is an important factor in controlling the sequence and the depositional filling of the basin. This article reports the assemble pat...In the continental lake basin whose structures were extraordinarily active, tectonism is an important factor in controlling the sequence and the depositional filling of the basin. This article reports the assemble patterns of syndepositional fault in the third member of Shahejie （沙河街） Formation in Beitang （北塘） sag. The results show that the comb-shape fracture system and the fracture transformation zone were developed in Beitang sag. These assemble patterns obviously controlled the sand-body and spatial distribution of sedimentary system. However, the steep slope belt of fault terrace, the multistage slope belt and the low uplift gentle slope belt controlled the development of sequence styles. Analyses of the spatial-temporal relationship of the assemble pattern of syndepositional faults and the sedimentary system help predict the favorable exploration zone.展开更多
Fine-grained rocks（FGR） are the important source rocks and reservoirs of shale hydrocarbon which is the prospect hotspot at present. Widely distributed fine-grained sediments（FGS） of the upper fourth member of Sha...Fine-grained rocks（FGR） are the important source rocks and reservoirs of shale hydrocarbon which is the prospect hotspot at present. Widely distributed fine-grained sediments（FGS） of the upper fourth member of Shahejie Formation in Dongying depression are taken as an example to study the space-time evolution and controlling factor of FGS in this paper. Based on the analysis of well cores, thin sections, inorganic and organic geochemistry indicators, FGR are divided into 7 types of lithofacies. Through the study of ‘point-line-plane＇, this study shows that FGS has the characteristics of rhythum, diversity and succession. The first stage is characterized by clayey FGS（massive claystone）. The second stage is characterized by carbonate FGS（low-TOC laminated limestone） and dolomitic FGS（dolomitic-silty shale） formed by transgression. The third stage is characterized by organic-rich carbonate FGS（middle/high-TOC laminated limestone） distributed in cycle. The fourth stage is characterized by FGS mixed carbonate and siliciclastic sediments（calcareous-silty shale）. A variety of space-time evolution of FGS are controlled by multiple factors including tectonism, climate and lake conditions.展开更多
基金the National Science and Technology Major Project of China(Grant Nos.2017ZX05036-002-004.2017ZX05005-001-003)National Basic Research Program of China(Grant No.2014CB239105)for financial support.
文摘To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected and analyzed using N2 adsorption, high-pressure mercury injection capillary pressure(MICP), nuclear magnetic resonance(NMR), high-speed centrifugation, and displacement image techniques. The results show that shale pore structure characteristics control shale oil movability directly. Movable oil saturation has a positive relationship with pore volume for radius > 2 μm, as larger pores often have higher movable oil saturation, indicating that movable oil is present in relatively larger pores. The main reasons for this are as follows. The relatively smaller pores often have oil-wetting properties because of organic matter, which has an unfavorable effect on the flow of oil, while the relatively larger pores are often wetted by water, which is helpful to shale oil movability. The rich surface provided by the relatively smaller pores is beneficial to the adsorption of immovable oil. Meanwhile, the relatively larger pores create significant pore volume for movable oil. Moreover, the larger pores often have good pore connectivity. Pores and fractures are interconnected to form a complex fracture network, which provides a good permeability channel for shale oil flow. The smaller pores are mostly distributed separately;thus, they are not conducive to the flow of shale oil. The mineral composition and fabric macroscopically affect the movability of shale oil. Calcite plays an active role in shale oil movability by increasing the brittleness of shale and is more likely to form micro-cracks under the same stress background. Clay does not utilize shale oil flow because of its large specific surface area and its block effect. The bedding structure increases the large-scale storage space and improves the connectivity of pores at different scales, which is conducive to the movability of shale oil.
文摘The glutenite in the fourth member of Shahejie Formation(Es^4) in northern Dongying depression straightforwardly penetrated into the muddy bathyal -abyss facies.The conditions of reservoir is very superior:(1) the high quality thick bedded oil source rock is developed very well in the Lijin sag and Minfeng sag of the study area,and it has the higher capability of generating hydrocarbon;(2) the
基金Supported by the PetroChina Science and Technology Project(2021DJ1904)PetroChina Exploration and Production Company Marine Shale Gas Selection Project(kt2018-01-06)。
文摘Based on anatomy of key areas and data points and analysis of typical features of shell layer in Guanyinqiao Member, basic characteristics of key interfaces, mainly bentonite layers, in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in the Sichuan Basin and its surrounding areas and the relationship between these key interfaces with the deposition of organic-rich shale have been examined systematically. The Wufeng Formation-Longmaxi Formation has four types of marker beds with interface attributes, namely, the characteristic graptolite belt, Guanyinqiao Member shell layer, section with dense bentonite layers, and concretion section, which can be taken as key interfaces for stratigraphic division and correlation of the graptolite shale. The shell layer in Guanyinqiao Member is the most standard key interface in Wufeng Formation-Longmaxi Formation, and can also be regarded as an important indicator for judging the depositional scale of organic-rich shale in key areas. There are 8 dense bentonite sections of two types mainly occurring in 7 graptolite belts in these formations. They have similar interface characteristics with the shell layer in Guanyinqiao Member in thickness and natural gamma response, and belong to tectonic interfaces(i.e., event deposits). They have three kinds of distribution scales: whole region, large part of the region, and local part, and can be the third, fourth and fifth order sequence interfaces, and have a differential control effect on organic-rich shale deposits. The horizon the characteristic graptolite belt occurs first is the isochronous interface, which is not directly related to the deposition of organic-rich shale. Concretions only appear in local areas, and show poor stability in vertical and horizontal directions, and have no obvious relationship with the deposition of the organic-rich shale.
基金Supported by the PetroChina Science and Technology Department Project(2012A-4802-02)National Key Basic Research and Development Program(2014CB239000)。
文摘Based on 991 groups of analysis data of shale samples from the Lower Member of the Cretaceous Eagle Ford Formation of 1317 production wells and 72 systematic coring wells in the U.S. Gulf Basin, the estimated ultimate recovery(EUR) of shale oil and gas of the wells are predicted by using two classical EUR estimation models, and the average values predicted excluding the effect of engineering factors are taken as the final EUR. Key geological factors controlling EUR of shale oil and gas are fully investigated. The reservoir capacity, resources, flow capacity and fracability are the four key geological parameters controlling EUR. The storage capacity of shale oil and gas is directly controlled by total porosity and hydrocarbon-bearing porosity, and indirectly controlled by total organic carbon(TOC) and vitrinite reflectance(Ro). The resources of shale oil and gas are controlled by hydrocarbon-bearing porosity and effective shale thickness etc. The flow capacity of shale oil and gas is controlled by effective permeability, crude oil density, gas-oil ratio, condensate oil-gas ratio, formation pressure gradient, and Ro. The fracability of shale is directly controlled by brittleness index, and indirectly controlled by clay content in volume. EUR of shale oil and gas is controlled by six geological parameters: it is positively correlated with effective shale thickness, TOC and fracture porosity, negatively correlated with clay content in volume, and increases firstly and then decreases with the rise of Ro and formation pressure gradient. Under the present upper limit of horizontal well fracturing effective thickness of 65 m and the lower limit of EUR of 3×10^(4) m^(3), when TOC<2.3%, or Ro<0.85%, or clay content in volume larger than 25%, and fractures and micro-fractures aren’t developed, favorable areas of shale oil and gas hardly occur.
基金This work was supported by PetroChina Major Science and Technology Project(No.2017E-015)PetroChina Key Project(No.kt2017-07).
文摘Tight oil in the redeposited carbonates was mainly distributed in the Lower Submember of Member 3 of Shahejie Formation in Shulu sag of Jizhong depression,North China.Through high-resolution 3D seismic data,well logging data and drilling data,the Lower Submember of Member 3 of Shahejie Formation was divided into 5 third-order sequences and 15 parasequence sets.The redeposited marl and rudstone were major reserving horizons of tight oil,and ten reserving space types were developed and could be classified into two main categories,i.e.,pores and fractures.Two types of tight oil reservoirs were established,i.e.,the marl hydrocarbon reservoir of the source-reservoir integration and the rudstone hydrocarbon reservoirs of the source-reservoir paragenesis.The assemblage relationship among the high-quality source rocks,system tracts with the source-reservoir configuration was the major control factor for tight oil accumulation in the redeposited carbonates.The lacustrine transgressive system tracts and highstand systems tracts in SQ1 to SQ5 were the favorable horizons for development of the marl hydrocarbon reservoir,the lowstand system tracts in SQ1 to SQ3 were the favorable horizons for development of the rudstone hydrocarbon reservoir.
基金supported by the Research Institute of Explora-tion and Development,Petro China Dagang Oilfield Company,the National Natural Science Foundation of China (No. 40872077)the Open Research Program of State Key Labora-tory of Geological Processes and Mineral Resources,China University of Geosciences (No.GPMR200913)the Foun-dation of Key Laboratory of Tectonics and Petroleum Re-sources of Ministry of Education,China University of Geo-sciences (No.TPR-2009-19)
文摘In the continental lake basin whose structures were extraordinarily active, tectonism is an important factor in controlling the sequence and the depositional filling of the basin. This article reports the assemble patterns of syndepositional fault in the third member of Shahejie （沙河街） Formation in Beitang （北塘） sag. The results show that the comb-shape fracture system and the fracture transformation zone were developed in Beitang sag. These assemble patterns obviously controlled the sand-body and spatial distribution of sedimentary system. However, the steep slope belt of fault terrace, the multistage slope belt and the low uplift gentle slope belt controlled the development of sequence styles. Analyses of the spatial-temporal relationship of the assemble pattern of syndepositional faults and the sedimentary system help predict the favorable exploration zone.
基金supported by the National Science and Technology Special Grant of China (No. 2017zx05036-004)
文摘Fine-grained rocks（FGR） are the important source rocks and reservoirs of shale hydrocarbon which is the prospect hotspot at present. Widely distributed fine-grained sediments（FGS） of the upper fourth member of Shahejie Formation in Dongying depression are taken as an example to study the space-time evolution and controlling factor of FGS in this paper. Based on the analysis of well cores, thin sections, inorganic and organic geochemistry indicators, FGR are divided into 7 types of lithofacies. Through the study of ‘point-line-plane＇, this study shows that FGS has the characteristics of rhythum, diversity and succession. The first stage is characterized by clayey FGS（massive claystone）. The second stage is characterized by carbonate FGS（low-TOC laminated limestone） and dolomitic FGS（dolomitic-silty shale） formed by transgression. The third stage is characterized by organic-rich carbonate FGS（middle/high-TOC laminated limestone） distributed in cycle. The fourth stage is characterized by FGS mixed carbonate and siliciclastic sediments（calcareous-silty shale）. A variety of space-time evolution of FGS are controlled by multiple factors including tectonism, climate and lake conditions.
