A large number of crude oil and rock samples from various oil pools of the Central Uplift in Dongying Depression were investigated to reveal the origin and accumulation of hydrocarbons. The results showed that the com...A large number of crude oil and rock samples from various oil pools of the Central Uplift in Dongying Depression were investigated to reveal the origin and accumulation of hydrocarbons. The results showed that the composition and areal distribution of hydrocarbons vary with the location of the oil pools. An increasing trend of gammacerane/C30-hopane and steranes/hopanes but a decreasing trend of prystane/phytane （Pr/Ph） and 18（H）-/17（H）- trisnorhopane （Ts/Tm） ratios were observed from southwest to northeast. This indicates a variation of source rocks and hydrocarbon properties. An increasing trend of water salinity with much more input of algae-rich microorganisms in the deposition environment of the source rock was observed from southwest to northeast. However, the thermal maturity of the source rocks showed a decreasing trend in the same direction. Oil-to-oil and oil-to-source rock correlations showed that most oils were sourced from Es3 and Es4 members with a burial depth of more than 3,000-3,150 m and 2,700 m respectively. The oils in the Shinan and Ying 11 sand bodies, which were generally mixed with the Es4 sourced oils, came mostly from Es3 mudstones. It is quite significant that the Es4 derived oils migrated vertically for hundreds of meters and accumulated in an overlying lithologic pool of the Es3^m, i.e., Ying 11 synclinal lithologic pool, which suggests that the mechanisms of migration and accumulation for subtle oil pools in the Dongying Depression are more complex than that of the previously expected.展开更多
The Huimin（惠民） depression is a third-level tectonic element of the Bohai（渤海） Bay basin in eastern China.The central uplift belt is the most important oil and gas accumulation zone in the depression,but the lac...The Huimin（惠民） depression is a third-level tectonic element of the Bohai（渤海） Bay basin in eastern China.The central uplift belt is the most important oil and gas accumulation zone in the depression,but the lack of adequate geological studies in the area has greatly hindered exploration and development.In this article,using seismic data,fracture mechanics,and a combination of data on fault growth indices and fault throws,we present an analysis of tectonic activity in the central uplift belt and adjacent regions.The amount of extension is calculated along balanced N-S cross-sections,along with the thickness of strata eroded from the fourth,third,and second members of the Shahejie（沙河街） Formation（Es4-Es2） in the uplift belt,by analyzing porosity and stratigraphic correlations.In addition,uplift features are described,and their timing and processes of formation are analyzed and dis-cussed.The results indicate that strike-slip and extensional tectonic movements coexisted,with the effects of the latter most obvious.The spatial and temporal nature of the extensional move-ments is varied：fault activity during the period Ek-Es4 was the strongest on the northern Ningnan（宁南） fault,and activity in the western part of the area was stronger than that in the east,which in turn was stronger than that in the central region;during Es3-Es2,the strongest fault movements were along the eastern part of the middle Linyi（临邑） fault,and activity in the western part of the area was rela-tively weak,whereas in the mid-west it was the strongest.The extensional movements were a response to the activity of the faults.The sediments in the lower part of the fourth member of the Shahejie For-mation（Es4x） show that Es4 was the time when the central belt first began to be uplifted strongly.Uplift was uneven during the Paleogene：the western part of the area was uplifted continuously,while the mid-eastern area underwent alternating periods of uplift and subsidence.During the Paleogene,a number of different tectonic features developed in the central uplift belt at different times and are manifested as follows：during the period Ek-Es4,a gentle slope was formed as part of the Zizhen（滋镇） sag;during Es3-Es2,the northern part of the central uplift belt continued to display a gentle slope as part of the Zizhen sag,but the southern region developed an steep slope as part of the Linnan（临南） sag.There are close interrelationships between uplift,strike-slip,and extension within the central uplift belt of the Huimin depression,as is manifest by the areas of strongest extension being uplifted most rapidly,and also eroded the most.展开更多
文摘A large number of crude oil and rock samples from various oil pools of the Central Uplift in Dongying Depression were investigated to reveal the origin and accumulation of hydrocarbons. The results showed that the composition and areal distribution of hydrocarbons vary with the location of the oil pools. An increasing trend of gammacerane/C30-hopane and steranes/hopanes but a decreasing trend of prystane/phytane （Pr/Ph） and 18（H）-/17（H）- trisnorhopane （Ts/Tm） ratios were observed from southwest to northeast. This indicates a variation of source rocks and hydrocarbon properties. An increasing trend of water salinity with much more input of algae-rich microorganisms in the deposition environment of the source rock was observed from southwest to northeast. However, the thermal maturity of the source rocks showed a decreasing trend in the same direction. Oil-to-oil and oil-to-source rock correlations showed that most oils were sourced from Es3 and Es4 members with a burial depth of more than 3,000-3,150 m and 2,700 m respectively. The oils in the Shinan and Ying 11 sand bodies, which were generally mixed with the Es4 sourced oils, came mostly from Es3 mudstones. It is quite significant that the Es4 derived oils migrated vertically for hundreds of meters and accumulated in an overlying lithologic pool of the Es3^m, i.e., Ying 11 synclinal lithologic pool, which suggests that the mechanisms of migration and accumulation for subtle oil pools in the Dongying Depression are more complex than that of the previously expected.
基金supported by the Natural Science Foundation of Shandong Province (No. ZR2009EQ002)the Foundation of the Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals (No. DMSM201005)+1 种基金the National Natural Science Foundation of China (No. 90814006)the Project of Excellent Young College Teachers Home Visiting Scholar during 2009 in Shandong Province, and the Postgraduate Innovation Foundation of Shandong University of Science and Technology (No. YCB100112)
文摘The Huimin（惠民） depression is a third-level tectonic element of the Bohai（渤海） Bay basin in eastern China.The central uplift belt is the most important oil and gas accumulation zone in the depression,but the lack of adequate geological studies in the area has greatly hindered exploration and development.In this article,using seismic data,fracture mechanics,and a combination of data on fault growth indices and fault throws,we present an analysis of tectonic activity in the central uplift belt and adjacent regions.The amount of extension is calculated along balanced N-S cross-sections,along with the thickness of strata eroded from the fourth,third,and second members of the Shahejie（沙河街） Formation（Es4-Es2） in the uplift belt,by analyzing porosity and stratigraphic correlations.In addition,uplift features are described,and their timing and processes of formation are analyzed and dis-cussed.The results indicate that strike-slip and extensional tectonic movements coexisted,with the effects of the latter most obvious.The spatial and temporal nature of the extensional move-ments is varied：fault activity during the period Ek-Es4 was the strongest on the northern Ningnan（宁南） fault,and activity in the western part of the area was stronger than that in the east,which in turn was stronger than that in the central region;during Es3-Es2,the strongest fault movements were along the eastern part of the middle Linyi（临邑） fault,and activity in the western part of the area was rela-tively weak,whereas in the mid-west it was the strongest.The extensional movements were a response to the activity of the faults.The sediments in the lower part of the fourth member of the Shahejie For-mation（Es4x） show that Es4 was the time when the central belt first began to be uplifted strongly.Uplift was uneven during the Paleogene：the western part of the area was uplifted continuously,while the mid-eastern area underwent alternating periods of uplift and subsidence.During the Paleogene,a number of different tectonic features developed in the central uplift belt at different times and are manifested as follows：during the period Ek-Es4,a gentle slope was formed as part of the Zizhen（滋镇） sag;during Es3-Es2,the northern part of the central uplift belt continued to display a gentle slope as part of the Zizhen sag,but the southern region developed an steep slope as part of the Linnan（临南） sag.There are close interrelationships between uplift,strike-slip,and extension within the central uplift belt of the Huimin depression,as is manifest by the areas of strongest extension being uplifted most rapidly,and also eroded the most.
