Modeling geomechanical properties of shales to make sense of their complex properties is at the forefront of petroleum exploration and exploitation application and has received much re- search attention in recent year...Modeling geomechanical properties of shales to make sense of their complex properties is at the forefront of petroleum exploration and exploitation application and has received much re- search attention in recent years. A shale＇s key geomechanical properties help to identify its ＂fracibility＂ its fluid flow patterns and rates, and its in-place petroleum resources and potential commercial re- serves. The models and the information they provide, in turn, enable engineers to design drilling pat- terns, fracture-stimulation programs and materials selection that will avoid formation damage and op- timize recovery of petroleum. A wide-range of tools, technologies, experiments and mathematical techniques are deployed to achieve this. Characterizing the interconnected fracture, permeability and porosity network is an essential step in understanding a shales highly-anisotropic features on multiple scales （nano to macro）. Weli-log data, and its petrophysical interpretation to calibrate many geome- chanical metrics to those measured in rock samples by laboratory techniques plays a key role in pro- viding affordable tools that can be deployed cost-effectively in multiple well bores. Likewise, micro- seismic data helps to match fracture density and propagation observed on a reservoir scale with pre- dictions from simulations and laboratory tests conducted on idealised/simplified discrete fracture net- work models. Shales complex wettability, adsorption and water imbibition characteristics have a sig- nificant influence on potential formation damage during stimulation and the short-term and long-term flow of petroleum achievable. Many gas flow mechanisms and models are proposed taking into ac- count the multiple flow mechanisms involved （e.g., desorption, diffusion, slippage and viscous flow op- erating at multiple porosity levels from nano- to macro-scales）. Fitting historical production data and well decline curves to model predictions helps to verify whether model＇s geomechanical assumptions are realistic or not. This review discusses the techniques applied and the models developed that are relevant to applied geomechanics, highlighting examples of their application and the numerous out- standin~ questions associated with them.展开更多
Taking the shale of the second member of the Paleogene Funing Formation in the Qintong Sag,Subei Basin,China,as an example,this study integrates methods such as rock section imaging,optical and electron microscopy,mic...Taking the shale of the second member of the Paleogene Funing Formation in the Qintong Sag,Subei Basin,China,as an example,this study integrates methods such as rock section imaging,optical and electron microscopy,micro-area mineral analysis and laser confocal in-situ observation,assisted by Wood’s alloy impregnation and other auxiliary techniques,to systematically investigate lamina types and combinations,pore-fracture units and fracture systems,hydrocarbon occurrence and shale oil enrichment patterns.The following results are obtained.(1)Three basic lamina types,i.e.felsic,clay-rich,and carbonate,are identified in the study area.Their combinations are controlled by the interplay of climate,hydrodynamics,and tectonics,with vertical distribution influenced by lake-level fluctuations and event sedimentation.(2)Reservoir space is controlled by lithological composition,predominantly comprising intergranular pores and fractures within felsic laminae and intercrystalline pores and fractures within clay-rich laminae,which together with dissolution pores and organic matter pores form a matrix pore-fracture system.This system,combined with bedding fractures,structural fractures,and overpressure fractures,constitutes a hierarchical and three-dimensional transport network.(3)The“felsic+clay-rich+organic-rich”lamina combination exhibits an optimal pore-fracture configuration,serving as the preferred shale oil reservoir unit,continuously distributed in sub-members Ⅰ-Ⅱ.(4)A“hierarchical migration-dynamic sealing”in-source enrichment model is established.Specifically,hydrocarbon generation in clay-rich laminae creates overpressure,driving migration through nanoscale pore-fracture networks and forming localized accumulations;subsequent fracture formation from overpressure breaches lamina interfaces,allowing hydrocarbons to migrate under capillary pressure into micrometer-scale porous domains in felsic laminae;structural fractures connect multiple laminae to form a 3D seepage system,while cementation zones associated with micro-faults and lamina interfaces create dynamic sealing.Ultimately,shale oil accumulates in source via the coupling of pores,fractures and laminae.展开更多
This study pertains to the evaluation of shale gas and rock physics properties of this area with respect to its total organic content of Sember Formation, Khiproarea, Pakistan. We use well logs data for this study. Th...This study pertains to the evaluation of shale gas and rock physics properties of this area with respect to its total organic content of Sember Formation, Khiproarea, Pakistan. We use well logs data for this study. The Khipro area is prominent in the Lower Indus Basin for its hydrocarbon (oil and gas) structural traps. In shale gas evaluation, TOC of Sember Formation is estimated. The analysis has been done with the help of the wire line data of the well Bilal North-01. The presence of shale gas in the study area is analyzed with the help of different techniques. Rock physics and petrophysical analysis have been done in order to get the properties of the area related to the shale gas evaluation.展开更多
This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation ...This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.展开更多
基金the Department of Science & Technology (DST Ministry of Science & Technology, Government of India), for providing funding for his research through the DST-Inspire Assured Opportunity of Research Career (AORC) scheme
文摘Modeling geomechanical properties of shales to make sense of their complex properties is at the forefront of petroleum exploration and exploitation application and has received much re- search attention in recent years. A shale＇s key geomechanical properties help to identify its ＂fracibility＂ its fluid flow patterns and rates, and its in-place petroleum resources and potential commercial re- serves. The models and the information they provide, in turn, enable engineers to design drilling pat- terns, fracture-stimulation programs and materials selection that will avoid formation damage and op- timize recovery of petroleum. A wide-range of tools, technologies, experiments and mathematical techniques are deployed to achieve this. Characterizing the interconnected fracture, permeability and porosity network is an essential step in understanding a shales highly-anisotropic features on multiple scales （nano to macro）. Weli-log data, and its petrophysical interpretation to calibrate many geome- chanical metrics to those measured in rock samples by laboratory techniques plays a key role in pro- viding affordable tools that can be deployed cost-effectively in multiple well bores. Likewise, micro- seismic data helps to match fracture density and propagation observed on a reservoir scale with pre- dictions from simulations and laboratory tests conducted on idealised/simplified discrete fracture net- work models. Shales complex wettability, adsorption and water imbibition characteristics have a sig- nificant influence on potential formation damage during stimulation and the short-term and long-term flow of petroleum achievable. Many gas flow mechanisms and models are proposed taking into ac- count the multiple flow mechanisms involved （e.g., desorption, diffusion, slippage and viscous flow op- erating at multiple porosity levels from nano- to macro-scales）. Fitting historical production data and well decline curves to model predictions helps to verify whether model＇s geomechanical assumptions are realistic or not. This review discusses the techniques applied and the models developed that are relevant to applied geomechanics, highlighting examples of their application and the numerous out- standin~ questions associated with them.
基金Supported by the National Natural Science Foundation of China(U24B6002)Project of the Technology Department of China Petroleum&Chemical Corporation(P24117,P23190).
文摘Taking the shale of the second member of the Paleogene Funing Formation in the Qintong Sag,Subei Basin,China,as an example,this study integrates methods such as rock section imaging,optical and electron microscopy,micro-area mineral analysis and laser confocal in-situ observation,assisted by Wood’s alloy impregnation and other auxiliary techniques,to systematically investigate lamina types and combinations,pore-fracture units and fracture systems,hydrocarbon occurrence and shale oil enrichment patterns.The following results are obtained.(1)Three basic lamina types,i.e.felsic,clay-rich,and carbonate,are identified in the study area.Their combinations are controlled by the interplay of climate,hydrodynamics,and tectonics,with vertical distribution influenced by lake-level fluctuations and event sedimentation.(2)Reservoir space is controlled by lithological composition,predominantly comprising intergranular pores and fractures within felsic laminae and intercrystalline pores and fractures within clay-rich laminae,which together with dissolution pores and organic matter pores form a matrix pore-fracture system.This system,combined with bedding fractures,structural fractures,and overpressure fractures,constitutes a hierarchical and three-dimensional transport network.(3)The“felsic+clay-rich+organic-rich”lamina combination exhibits an optimal pore-fracture configuration,serving as the preferred shale oil reservoir unit,continuously distributed in sub-members Ⅰ-Ⅱ.(4)A“hierarchical migration-dynamic sealing”in-source enrichment model is established.Specifically,hydrocarbon generation in clay-rich laminae creates overpressure,driving migration through nanoscale pore-fracture networks and forming localized accumulations;subsequent fracture formation from overpressure breaches lamina interfaces,allowing hydrocarbons to migrate under capillary pressure into micrometer-scale porous domains in felsic laminae;structural fractures connect multiple laminae to form a 3D seepage system,while cementation zones associated with micro-faults and lamina interfaces create dynamic sealing.Ultimately,shale oil accumulates in source via the coupling of pores,fractures and laminae.
文摘This study pertains to the evaluation of shale gas and rock physics properties of this area with respect to its total organic content of Sember Formation, Khiproarea, Pakistan. We use well logs data for this study. The Khipro area is prominent in the Lower Indus Basin for its hydrocarbon (oil and gas) structural traps. In shale gas evaluation, TOC of Sember Formation is estimated. The analysis has been done with the help of the wire line data of the well Bilal North-01. The presence of shale gas in the study area is analyzed with the help of different techniques. Rock physics and petrophysical analysis have been done in order to get the properties of the area related to the shale gas evaluation.
基金Supported by the National Natural Science Foundation of China(U22B6002)PetroChina Science Research and Technology Development Project(2021DJ0101)。
文摘This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.
