Based on drilling geological,geochemical,geophysical and production test data,the characteristics of source rocks,reservoir rocks and caprocks,as well as the process of hydrocarbon generation,trap evolution and oil ac...Based on drilling geological,geochemical,geophysical and production test data,the characteristics of source rocks,reservoir rocks and caprocks,as well as the process of hydrocarbon generation,trap evolution and oil accumulation of the oil-bearing assemblage composed of the Cretaceous Yingcheng Formation(K1yc)and Denglouku Formation(K1d)in the Shuangcheng area,northern Songliao Basin,NE China,were analyzed by using the research methods for petroleum systems.The source rocks mainly exist in K1yc,with the organic matters mainly originated from lower aquatic organisms and algae,and reaching the grade of high-quality source rock in terms of organic abundance.The crude oil,which is characterized by low density,high freezing point and high wax content,is believed to have generated by the K1yc source rocks.The reservoir rocks include K1d sandstones and K1yc glutenites.The mudstone in the fourth member of K1d serves as the direct caprock of the oil reservoir.The oil was generated during the period between Yaojia Formation and Nenjiang Formation,and then accumulated during the periods of Nenjiang Formation and Paleogene–Neogene.The traps evolved in three stages:the late Yingcheng Formation,the late Quantou Formation and the late Nenjiang Formation,forming structural and structural-lithologic reservoirs.It is concluded that good source-reservoir-caprock assemblage,late hydrocarbon charging,short migration distance and stable tectonic setting are favorable factors for the formation of oil reservoirs.展开更多
The Changling gas field is occurs in tight sandstone reservoirs of the Lower Cretaceous Denglouku Formation in the Changling fault depression,southern Songliao Basin,China,which constitutes a new gas-producing area in...The Changling gas field is occurs in tight sandstone reservoirs of the Lower Cretaceous Denglouku Formation in the Changling fault depression,southern Songliao Basin,China,which constitutes a new gas-producing area in the depression. Using information on the source-reservoir-cap rock assemblage of the Denglouku Formation,fault activity,and single well burial history of well CS1,together with data on reservoir fluid inclusion and laser Raman spectroscopy,we described the formation of the Changling gas field and determine that this fault depression did not possess suitable conditions for hydrocarbon generation. Coal-derived methane generated from underlying hydrocarbon source rock accumulated in the Lower Cretaceous Yingcheng Formation. At the end of the Late Cretaceous Qingshankou Stage,underwater volcanic eruptions occurred in the northern part of the Changling gas field near Qian'an,resulting in the reactivation of deep faults. Mantle-sourced inorganic CO2 migrated along faults to hydrocarbon gas reservoirs in volcanic rocks of the Yingcheng Formation; Meanwhile,displaced methane( hydrocarbon gas) migrated upward to sand reservoirs of the Denglouku Formation.The methane accumulated and formed secondary gas reservoirs,Therefore fault activity was the main factor controlling the generation of gas reservoirs in the Denglouku Formation. The main accumulation period of the Yingcheng hydrocarbon gas reservoirs was 82 Ma. Whereas gas reservoir formation in the overlying Denglongku Formation was 79 Ma,slightly later than the time of formation of the Yingcheng gas reservoir in CS1 well area.At 79 Ma,the burial depth of the Denglouku Formation was 1 800--2 000 m,the diagenesis is relatively weak and the physical properties of the reservoir are relatively favorable for accumulation. This period is not only at gas generation peak time of three sets of source rock but also at the reactivation of deep faults during the formation of fault-bound depressions,thereby providing favorable conditions for the migration and accumulation of methane.展开更多
基金Supported by the National Natural Science Foundation of China(U20A201009,41972157).
文摘Based on drilling geological,geochemical,geophysical and production test data,the characteristics of source rocks,reservoir rocks and caprocks,as well as the process of hydrocarbon generation,trap evolution and oil accumulation of the oil-bearing assemblage composed of the Cretaceous Yingcheng Formation(K1yc)and Denglouku Formation(K1d)in the Shuangcheng area,northern Songliao Basin,NE China,were analyzed by using the research methods for petroleum systems.The source rocks mainly exist in K1yc,with the organic matters mainly originated from lower aquatic organisms and algae,and reaching the grade of high-quality source rock in terms of organic abundance.The crude oil,which is characterized by low density,high freezing point and high wax content,is believed to have generated by the K1yc source rocks.The reservoir rocks include K1d sandstones and K1yc glutenites.The mudstone in the fourth member of K1d serves as the direct caprock of the oil reservoir.The oil was generated during the period between Yaojia Formation and Nenjiang Formation,and then accumulated during the periods of Nenjiang Formation and Paleogene–Neogene.The traps evolved in three stages:the late Yingcheng Formation,the late Quantou Formation and the late Nenjiang Formation,forming structural and structural-lithologic reservoirs.It is concluded that good source-reservoir-caprock assemblage,late hydrocarbon charging,short migration distance and stable tectonic setting are favorable factors for the formation of oil reservoirs.
基金Supported by Project of National Natural Science Foundation of China(No.41472101)
文摘The Changling gas field is occurs in tight sandstone reservoirs of the Lower Cretaceous Denglouku Formation in the Changling fault depression,southern Songliao Basin,China,which constitutes a new gas-producing area in the depression. Using information on the source-reservoir-cap rock assemblage of the Denglouku Formation,fault activity,and single well burial history of well CS1,together with data on reservoir fluid inclusion and laser Raman spectroscopy,we described the formation of the Changling gas field and determine that this fault depression did not possess suitable conditions for hydrocarbon generation. Coal-derived methane generated from underlying hydrocarbon source rock accumulated in the Lower Cretaceous Yingcheng Formation. At the end of the Late Cretaceous Qingshankou Stage,underwater volcanic eruptions occurred in the northern part of the Changling gas field near Qian'an,resulting in the reactivation of deep faults. Mantle-sourced inorganic CO2 migrated along faults to hydrocarbon gas reservoirs in volcanic rocks of the Yingcheng Formation; Meanwhile,displaced methane( hydrocarbon gas) migrated upward to sand reservoirs of the Denglouku Formation.The methane accumulated and formed secondary gas reservoirs,Therefore fault activity was the main factor controlling the generation of gas reservoirs in the Denglouku Formation. The main accumulation period of the Yingcheng hydrocarbon gas reservoirs was 82 Ma. Whereas gas reservoir formation in the overlying Denglongku Formation was 79 Ma,slightly later than the time of formation of the Yingcheng gas reservoir in CS1 well area.At 79 Ma,the burial depth of the Denglouku Formation was 1 800--2 000 m,the diagenesis is relatively weak and the physical properties of the reservoir are relatively favorable for accumulation. This period is not only at gas generation peak time of three sets of source rock but also at the reactivation of deep faults during the formation of fault-bound depressions,thereby providing favorable conditions for the migration and accumulation of methane.
