Reservoir quality varies greatly in the Shahejie Formation in the Dongying Sag. It is essential to analyze the variation and mechanisms of reservoir quality for determining the controlling factors based on cores, poro...Reservoir quality varies greatly in the Shahejie Formation in the Dongying Sag. It is essential to analyze the variation and mechanisms of reservoir quality for determining the controlling factors based on cores, porosity measurements and fluid inclusion techniques and so on. The sandstones in the fluvial, （fan） delta-front have the best reservoir quality due to the depositional conditions mechanically controlling the petrology configuration and the primary porosity, and chemically influencing the diagenesis and development of secondary pores. The activity of the boundary faults and the sedimentary facies dominate the variation of reservoir quality in different areas and intervals. The reservoir quality varies with the position of sandstone beds in different vertical models of sandstone and mudstone. This mainly arose from the strong cementation or strong dissolution in the sandstone caused by the diagenesis evolution of adjacent mudstone. With higher oil saturation reservoir quality is better because the hydrocarbon charge favors dissolution and restricts cementation. Diagenesis, depositional conditions and tectonic setting are the key controls of reservoir quality in the Shahejie Formation of the Dongying Sag.展开更多
The pore structure and its influence on physical properties and oil saturation of the Triassic Chang 7 sandstones,Ordos Basin were discussed using thin sections,physical properties,oil saturation and mercury intrusion...The pore structure and its influence on physical properties and oil saturation of the Triassic Chang 7 sandstones,Ordos Basin were discussed using thin sections,physical properties,oil saturation and mercury intrusion data.The results show that the tight sandstone has a binary pore structure:when the pore throat radius is larger than the peak radius,the pore radius is significantly larger than throat size,the pore structure is similar to the bead-string model with no fractal feature,and the pore throat volume is determined by the pore volume.When the pore throat radius is smaller than the peak radius,the pore structure is close to the capillary model and shows fractal features,the pore size is close to the throat size,and the pore throat volume is determined by the throat radius.The development of pore throats larger than the peak radius provides most of the oil storage space and is the major controlling factor for the porosity and permeability variation of tight sandstone.The pore throat smaller than the peak radius(including throats with no mercury invaded)contributes major reservoir space,it shows limited variation and has little effect on the change of physical properties which is lack of correlation with oil saturation.The pore throat larger than the peak radius is mainly composed of secondary and intergranular pores.Therefore genesis and main controlling factors of large pores such as intergranular and dissolved pores should be emphasized when predicting the tight sandstones quality.展开更多
There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of st...There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of stable depression-compression-extension.The first three types of basins had been intensely influenced by Hercynian and Alpine tectonic movement,while the later two types of basins always exist in a stable extension environment.Different basin evolution caused the obviously hydrocarbon distribution difference.In North Africa,marginal craton sag and rift basins show great expedition potential of hydrocarbon,marginal craton sag basins had good formation and preservation of Lower Silurian hot shale,tectonic-strata traps and migration pathway formed by Hercynian unconformity,and rift basins had excellent Upper Cretaceous marine source rocks and good hydrocarbon preservation with little tectonic activity.Meanwhile,in the salt-containing passive margin basins and delta basins of West Africa,thick strata containing high quality source rocks and plastic strata were well developed.Source rocks of high maturity,good hydrocarbon preservation,growth faults and deformational structure traps were formed by abundant overlying sediments and sources supplied from Tertiary large water system.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. ZX20130157)Science Foundation of China University of Petroleum, Beijing (Grant No. KYJJ2012-01-29)the Key Technologies Research and Development Program of the Chinese Tenth Five-Year Plan (Grant No. 2001BA605A-09)
文摘Reservoir quality varies greatly in the Shahejie Formation in the Dongying Sag. It is essential to analyze the variation and mechanisms of reservoir quality for determining the controlling factors based on cores, porosity measurements and fluid inclusion techniques and so on. The sandstones in the fluvial, （fan） delta-front have the best reservoir quality due to the depositional conditions mechanically controlling the petrology configuration and the primary porosity, and chemically influencing the diagenesis and development of secondary pores. The activity of the boundary faults and the sedimentary facies dominate the variation of reservoir quality in different areas and intervals. The reservoir quality varies with the position of sandstone beds in different vertical models of sandstone and mudstone. This mainly arose from the strong cementation or strong dissolution in the sandstone caused by the diagenesis evolution of adjacent mudstone. With higher oil saturation reservoir quality is better because the hydrocarbon charge favors dissolution and restricts cementation. Diagenesis, depositional conditions and tectonic setting are the key controls of reservoir quality in the Shahejie Formation of the Dongying Sag.
基金Supported by the China National Science and Technology Major Project(2017ZX05063002-009)China Postdoctoral Science Foundation(2015M580797).
文摘The pore structure and its influence on physical properties and oil saturation of the Triassic Chang 7 sandstones,Ordos Basin were discussed using thin sections,physical properties,oil saturation and mercury intrusion data.The results show that the tight sandstone has a binary pore structure:when the pore throat radius is larger than the peak radius,the pore radius is significantly larger than throat size,the pore structure is similar to the bead-string model with no fractal feature,and the pore throat volume is determined by the pore volume.When the pore throat radius is smaller than the peak radius,the pore structure is close to the capillary model and shows fractal features,the pore size is close to the throat size,and the pore throat volume is determined by the throat radius.The development of pore throats larger than the peak radius provides most of the oil storage space and is the major controlling factor for the porosity and permeability variation of tight sandstone.The pore throat smaller than the peak radius(including throats with no mercury invaded)contributes major reservoir space,it shows limited variation and has little effect on the change of physical properties which is lack of correlation with oil saturation.The pore throat larger than the peak radius is mainly composed of secondary and intergranular pores.Therefore genesis and main controlling factors of large pores such as intergranular and dissolved pores should be emphasized when predicting the tight sandstones quality.
文摘There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of stable depression-compression-extension.The first three types of basins had been intensely influenced by Hercynian and Alpine tectonic movement,while the later two types of basins always exist in a stable extension environment.Different basin evolution caused the obviously hydrocarbon distribution difference.In North Africa,marginal craton sag and rift basins show great expedition potential of hydrocarbon,marginal craton sag basins had good formation and preservation of Lower Silurian hot shale,tectonic-strata traps and migration pathway formed by Hercynian unconformity,and rift basins had excellent Upper Cretaceous marine source rocks and good hydrocarbon preservation with little tectonic activity.Meanwhile,in the salt-containing passive margin basins and delta basins of West Africa,thick strata containing high quality source rocks and plastic strata were well developed.Source rocks of high maturity,good hydrocarbon preservation,growth faults and deformational structure traps were formed by abundant overlying sediments and sources supplied from Tertiary large water system.
