The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks,...The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks, fluorescence microscopic features and fluid inclusion petrography. There were two main stages of hydrocarbon generation and expulsion of oil from the major hydrocarbon source rocks. The first stage was the main hydrocarbon expulsion stage. The fluorescence microscopic features also indicated two stages of hydrocarbon accumulation. Carbonaceous bitumen, asphaltene bitumen and colloidal bitumen reflected an early hydrocarbon charge, whereas the oil bitumen reflected a second hydrocarbon charge. Hydrocarbon inclusions also indicate two distinct charges according to the diagenetic evolution sequence, inclusion petrography features combined with the homogenization temperature and reservoir burial history analysis. According to these comprehensive analysis results, the hydrocarbon charge history of the Paleogene reservoir in the northern Dongpu Depression was divided into two phases. The first phase was from the late Dongying depositional period of the Oligocene to the early uplift stages of the late Paleogene. The second phase was from the late Minghuazhen period of the Pliocene to the Quaternary. Reservoirs formed during the first period were widely distributed covering the entire area. In contrast,reservoirs formed during the second period were mainly distributed near the hydrocarbon generation sags. Vertically, it was characterized by a single phase in the upper layers and two phases in the lower layers of the Paleogene.展开更多
Comparative analyses of petroleum generation potential,reservoir volume,frackability,and oil mobility were conducted on 102 shale cores from the Dongpu Depression.Results show the shale has high organic matter content...Comparative analyses of petroleum generation potential,reservoir volume,frackability,and oil mobility were conducted on 102 shale cores from the Dongpu Depression.Results show the shale has high organic matter contents composed of oil-prone type I and type II kerogens within the oil window.Various types of pores and fractures exist in the shale,with a porosity of up to 14.9%.The shale has high brittle mineral contents,extensive fractures,and high potential for oil mobility due to high seepage capacity and overpressure.Although the petroleum generation potential of the shale at Well PS18-8 is relatively greater than that at Well PS18-1,oil content of the latter is greater due to the greater TOC.The porosity and fracture density observed in Well PS18-1 are greater and more conducive to shale oil enrichment.Although the shales in Wells PS18-1 and PS18-8 have similar brittle mineral contents,the former is more favorable for anthropogenic fracturing due to a higher preexisting fracture density.Besides,the shale at Well PS18-1 has a higher seepage capacity and overpressure and therefore a higher oil mobility.The fracture density and overpressure play key roles in shale oil enrichment.展开更多
With the increasing exploration and development of typical hydrocarbon-rich depressions,such as the Dongpu Depression,the exploitation difficulty of shallow formations is increasing.There is an urgent need to clarify ...With the increasing exploration and development of typical hydrocarbon-rich depressions,such as the Dongpu Depression,the exploitation difficulty of shallow formations is increasing.There is an urgent need to clarify the hydrocarbon generation mode and hydrocarbon generation histories in deep formations.In this study,a gold tube-autoclave closed system was used to simulate the hydrocarbon generation processes and establish the hydrocarbon generation mode of different types of kerogen.Then,constrained by the thermal history and hydrocarbon generation kinetics,hydrocarbon generation histories were modeled.The results show that hydrocarbon generation evolution can be divided into five stages,and the maturity of each stage is different.The hydrocarbon generation history of the source rocks of the Shahejie 3 Formation mainly dates from the early depositional period of the Shahejie 1 Formation to the middle depositional period of the Dongying Formation.Hydrocarbon generation history constrained by thermal history and hydrocarbon generation kinetics is more in line with actual geological conditions.Moreover,this research can provide important hydrocarbon generation parameters for deep oil and gas exploration and exploitation of the Shahejie 3 Formation in the Dongpu Depression.展开更多
Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing ha...Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing halite and gypsum. The effect of gypsum minerals on residual oil content and chemical fractionation remains unclear. In this study, shale samples with different gypsum contents were used in organic geochemical experiments, showing that the high total organic matter (TOC) content and type II kerogen leads to a high residual oil content, as shown by high values of volatile hydrocarbon (S1) and extractable organic matter (EOM). XRD and FE-SEM result indicate that the existence of gypsum in saline shale contributes to an enhanced pore space and a higher residual oil content in comparison to non-gypsum shale. Additionally, the increase in the gypsum mineral content leads to an increase in the saturated hydrocarbon percentage and a decrease in polar components percentage (resins and asphaltene). Furthermore, thermal simulation experiments on low-mature saline shale show that the percentage of saturated hydrocarbons in the residual oil is high and remains stable and that the storage space is mainly mesoporous (> 20 nm) in the oil expulsion stage. However, the saturated hydrocarbons percentage decreases rapidly, and oil exists in mesopores (> 20 nm and < 5 nm) in the gas expulsion stage. In general, gypsum is conducive to the development of pore space, the adsorption of hydrocarbons and the occurrence of saturated hydrocarbon, leading to large quantities of residual oil. The data in this paper should prove to be reliable for shale oil exploration in saline lacustrine basins.展开更多
The Dongpu depression has experienced a complicated evolution of structure since Mesozoic. The Paleozoic carbonate rock has been strongly reformed and the buried hills with different characteristics of structure are d...The Dongpu depression has experienced a complicated evolution of structure since Mesozoic. The Paleozoic carbonate rock has been strongly reformed and the buried hills with different characteristics of structure are developed in the depression. There exist lots of groups of fault structures with strikes of NNE(or NE),NW, near NS and EW etc., of which the faults with strikes of NNE and NW play an important controlling role on present-day structural framework of the depression. The faults with near NS-striking and EW-striking deeply affect the establishment of structural framework of basement of the depression. Although most of the fractures are filled by calcite and other minerals, under the action of later structural stress, the earlier fractures could change their features into tensional ones. Therefore, much attention should be paid to the exploration and exploitation of Paleozoic oil and gas in Dongpu depression.展开更多
The Dongpu Depression is a secondary salt-bearing tectonic unit in the Bohai Bay Basin,eastern China.The depositional environment of this depression regarding its Paleogene strata is clearly different in plane,includi...The Dongpu Depression is a secondary salt-bearing tectonic unit in the Bohai Bay Basin,eastern China.The depositional environment of this depression regarding its Paleogene strata is clearly different in plane,including the saltwater environment(SE)in the north,the freshwater environment(FE)in the south and the brackish water environment(BE)in the middle.The result of oil and gas exploration in the Dongpu Depression shows that more than 90%of the proven oil reserves are distributed in the northern saltwater environment.Previous studies indicate that the organic geochemistry characteristics and the hydrocarbon generation capacity of the source rocks are very clearly diverse under different environments,which results in the significant differences in the proved reserves between the north and the south.In order to further explore the differences in the hydrocarbon generation capacity of the source rocks under distinct depositional environments and the mechanism of their occurrence,three samples from different depositional environments(W18-5 for SE,H7-18 for BE,CH9 for FE)were used for confined gold tube pyrolysis experiments.The results show that the CH4 yields of W18-5,H7-18 and CH9 increase with increasing temperature,the maximum yields being 405.62 mg/g TOC,388.56 mg/g TOC and 367.89 mg/g TOC,respectively.The liquid hydrocarbon yields of W18-5,H7-18 and CH9 firstly increase with increasing temperature and then decrease after the critical temperatures.The maximum yields of C6-14 are 149.54 mg/g TOC,140.18 mg/g TOC and 116.94 mg/g TOC,the maximum yields of C14+being 852.4 mg/g TOC,652.6 mg/g TOC and 596.41 mg/g TOC,respectively for W18-5,H7-18 and CH9.To summarize,the order of hydrocarbon potential from high to low is W18-5,H7-18 and CH9.On this basis,through analyzing the influencing factors of hydrocarbon differences,this paper reveals that the saltwater environment is characterized by 4 factors:higher salinity,halophilic algae,high paleo-productivity and a strongly reducing environment,which are beneficial to the enrichment of organic matter and lead to the formation of high levels of sapropelite and exinite.According to the variation of oil and gas components in the pyrolysis experiments,the hydrocarbon generation process is divided into three stages:kerogen cracking,oil cracking and C2-5 cracking.Combined with hydrocarbon generation characteristics and stages,the evolutionary model of hydrocarbon generation for source rocks under different environments is established.展开更多
Dongpu depression is a fault basin at residual-mobility period of Diwa stage, it developed on the strata of the Mesozoie and Pre-Mesozoie. It is one of the important oil/gas- bearing basin during Cenozoie era along th...Dongpu depression is a fault basin at residual-mobility period of Diwa stage, it developed on the strata of the Mesozoie and Pre-Mesozoie. It is one of the important oil/gas- bearing basin during Cenozoie era along the East China. The strueture in Dongpu geodepression is very complex. There exists a strueture pattern with east- and west-depression belts and one central swell belt, it is divided into the southern- and northern-division by Gaopingji (orMeng Ju ) -Xieheng fault.展开更多
Data from the super-deep wells (PS10, PS14 and YS1) led to the discovery of widespread metal-bearing hydrothermal fluids (or hot brines ) related to basic magrmas in the Lower Tertiary clastic sequence in the Dongpu D...Data from the super-deep wells (PS10, PS14 and YS1) led to the discovery of widespread metal-bearing hydrothermal fluids (or hot brines ) related to basic magrmas in the Lower Tertiary clastic sequence in the Dongpu Depression. In terms of SEM and EDAX analyses, pore-casting thin asction examination of sandstone, the composition and forming temperature of fluld inclusions, the trace element composition of mudstone and kerogen and organic geochemical analyses, it is demonstrated that the hydrothermal fluids ekisting in the area studied are ejecting fluids, which have a close bearing on diagenesis and edimentation, rather than intrusive veins along the tectonic fractures.The main indicators of hydrothermal activity are: (1 ) abnormal alteration of kerogen, (2)high-temperature alteted mineral assemblage; (3) abnormal distribution of hydrocarbons; (4) specific assemblages and abnormal contents of heavy metals in mudstone and kerogen; (5) specific composition of complex compounds and assemblages of fluid inclusions in sandstone: (6) periodic basaltic magma activity.Results of geological observations and laboratory simuating experiments demonstrated that the hydrothermal fluids have a close bearing on hydrocarbon generation in the Dongpu Depression. Two aspects of the effect of hydrothermal fluids are noticed: hydrothermal hydrocarbon production and strong metal catalysis in oil and gas generation.展开更多
Fission track analysis can provide important information of paleotemperatures and its temporal change, and is a very favourable method to solve geothermal problems in fine spacetime scale. According to the determinati...Fission track analysis can provide important information of paleotemperatures and its temporal change, and is a very favourable method to solve geothermal problems in fine spacetime scale. According to the determination of apatite fission track ages and length, the annealing characteristics of apatite fission track, geothermal evolution and prediction of petroleum source in studied area are discussed.展开更多
基金supported by the Important National Science&Technology Specific Projects(Grant No.2011ZX05006-003/004)
文摘The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks, fluorescence microscopic features and fluid inclusion petrography. There were two main stages of hydrocarbon generation and expulsion of oil from the major hydrocarbon source rocks. The first stage was the main hydrocarbon expulsion stage. The fluorescence microscopic features also indicated two stages of hydrocarbon accumulation. Carbonaceous bitumen, asphaltene bitumen and colloidal bitumen reflected an early hydrocarbon charge, whereas the oil bitumen reflected a second hydrocarbon charge. Hydrocarbon inclusions also indicate two distinct charges according to the diagenetic evolution sequence, inclusion petrography features combined with the homogenization temperature and reservoir burial history analysis. According to these comprehensive analysis results, the hydrocarbon charge history of the Paleogene reservoir in the northern Dongpu Depression was divided into two phases. The first phase was from the late Dongying depositional period of the Oligocene to the early uplift stages of the late Paleogene. The second phase was from the late Minghuazhen period of the Pliocene to the Quaternary. Reservoirs formed during the first period were widely distributed covering the entire area. In contrast,reservoirs formed during the second period were mainly distributed near the hydrocarbon generation sags. Vertically, it was characterized by a single phase in the upper layers and two phases in the lower layers of the Paleogene.
基金This study was fnancially supported by the China Postdoctoral Science Foundation(2019M660054)Science Foundation of China University of Petroleum(Beijing)(2462019BJRC005)+3 种基金Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01-05)Natural Science Foundation of China(41872148,41872128)NSFC Basic Research Program on Deep Petroleum Resource Accumulation and Key Engineering Technologies(U19B6003-02)the Science Projects of the Sinopec Zhongyuan Oilfeld Company(P15022).
文摘Comparative analyses of petroleum generation potential,reservoir volume,frackability,and oil mobility were conducted on 102 shale cores from the Dongpu Depression.Results show the shale has high organic matter contents composed of oil-prone type I and type II kerogens within the oil window.Various types of pores and fractures exist in the shale,with a porosity of up to 14.9%.The shale has high brittle mineral contents,extensive fractures,and high potential for oil mobility due to high seepage capacity and overpressure.Although the petroleum generation potential of the shale at Well PS18-8 is relatively greater than that at Well PS18-1,oil content of the latter is greater due to the greater TOC.The porosity and fracture density observed in Well PS18-1 are greater and more conducive to shale oil enrichment.Although the shales in Wells PS18-1 and PS18-8 have similar brittle mineral contents,the former is more favorable for anthropogenic fracturing due to a higher preexisting fracture density.Besides,the shale at Well PS18-1 has a higher seepage capacity and overpressure and therefore a higher oil mobility.The fracture density and overpressure play key roles in shale oil enrichment.
基金funded by the National Major Science and Technology Projects of China(Grant No.2016ZX05006-004)the Sichuan Youth Science and Technology Foundation(Grant No.2016JQ0043)the National Natural Science Foundation of China(Grant No.41972144)
文摘With the increasing exploration and development of typical hydrocarbon-rich depressions,such as the Dongpu Depression,the exploitation difficulty of shallow formations is increasing.There is an urgent need to clarify the hydrocarbon generation mode and hydrocarbon generation histories in deep formations.In this study,a gold tube-autoclave closed system was used to simulate the hydrocarbon generation processes and establish the hydrocarbon generation mode of different types of kerogen.Then,constrained by the thermal history and hydrocarbon generation kinetics,hydrocarbon generation histories were modeled.The results show that hydrocarbon generation evolution can be divided into five stages,and the maturity of each stage is different.The hydrocarbon generation history of the source rocks of the Shahejie 3 Formation mainly dates from the early depositional period of the Shahejie 1 Formation to the middle depositional period of the Dongying Formation.Hydrocarbon generation history constrained by thermal history and hydrocarbon generation kinetics is more in line with actual geological conditions.Moreover,this research can provide important hydrocarbon generation parameters for deep oil and gas exploration and exploitation of the Shahejie 3 Formation in the Dongpu Depression.
基金funded by the National Natural Science Foundation of China (NSFC) (41872128)the Science Foundation of China University of Petroleum, Beijing (No. 2462020YXZZ021).
文摘Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing halite and gypsum. The effect of gypsum minerals on residual oil content and chemical fractionation remains unclear. In this study, shale samples with different gypsum contents were used in organic geochemical experiments, showing that the high total organic matter (TOC) content and type II kerogen leads to a high residual oil content, as shown by high values of volatile hydrocarbon (S1) and extractable organic matter (EOM). XRD and FE-SEM result indicate that the existence of gypsum in saline shale contributes to an enhanced pore space and a higher residual oil content in comparison to non-gypsum shale. Additionally, the increase in the gypsum mineral content leads to an increase in the saturated hydrocarbon percentage and a decrease in polar components percentage (resins and asphaltene). Furthermore, thermal simulation experiments on low-mature saline shale show that the percentage of saturated hydrocarbons in the residual oil is high and remains stable and that the storage space is mainly mesoporous (> 20 nm) in the oil expulsion stage. However, the saturated hydrocarbons percentage decreases rapidly, and oil exists in mesopores (> 20 nm and < 5 nm) in the gas expulsion stage. In general, gypsum is conducive to the development of pore space, the adsorption of hydrocarbons and the occurrence of saturated hydrocarbon, leading to large quantities of residual oil. The data in this paper should prove to be reliable for shale oil exploration in saline lacustrine basins.
文摘The Dongpu depression has experienced a complicated evolution of structure since Mesozoic. The Paleozoic carbonate rock has been strongly reformed and the buried hills with different characteristics of structure are developed in the depression. There exist lots of groups of fault structures with strikes of NNE(or NE),NW, near NS and EW etc., of which the faults with strikes of NNE and NW play an important controlling role on present-day structural framework of the depression. The faults with near NS-striking and EW-striking deeply affect the establishment of structural framework of basement of the depression. Although most of the fractures are filled by calcite and other minerals, under the action of later structural stress, the earlier fractures could change their features into tensional ones. Therefore, much attention should be paid to the exploration and exploitation of Paleozoic oil and gas in Dongpu depression.
基金granted by the Science Foundation of the Chinese University of Petroleum,Beijing(Grant No.2462020YXZZ021)the National Natural Science Foundation of China(Grant No.41872128)。
文摘The Dongpu Depression is a secondary salt-bearing tectonic unit in the Bohai Bay Basin,eastern China.The depositional environment of this depression regarding its Paleogene strata is clearly different in plane,including the saltwater environment(SE)in the north,the freshwater environment(FE)in the south and the brackish water environment(BE)in the middle.The result of oil and gas exploration in the Dongpu Depression shows that more than 90%of the proven oil reserves are distributed in the northern saltwater environment.Previous studies indicate that the organic geochemistry characteristics and the hydrocarbon generation capacity of the source rocks are very clearly diverse under different environments,which results in the significant differences in the proved reserves between the north and the south.In order to further explore the differences in the hydrocarbon generation capacity of the source rocks under distinct depositional environments and the mechanism of their occurrence,three samples from different depositional environments(W18-5 for SE,H7-18 for BE,CH9 for FE)were used for confined gold tube pyrolysis experiments.The results show that the CH4 yields of W18-5,H7-18 and CH9 increase with increasing temperature,the maximum yields being 405.62 mg/g TOC,388.56 mg/g TOC and 367.89 mg/g TOC,respectively.The liquid hydrocarbon yields of W18-5,H7-18 and CH9 firstly increase with increasing temperature and then decrease after the critical temperatures.The maximum yields of C6-14 are 149.54 mg/g TOC,140.18 mg/g TOC and 116.94 mg/g TOC,the maximum yields of C14+being 852.4 mg/g TOC,652.6 mg/g TOC and 596.41 mg/g TOC,respectively for W18-5,H7-18 and CH9.To summarize,the order of hydrocarbon potential from high to low is W18-5,H7-18 and CH9.On this basis,through analyzing the influencing factors of hydrocarbon differences,this paper reveals that the saltwater environment is characterized by 4 factors:higher salinity,halophilic algae,high paleo-productivity and a strongly reducing environment,which are beneficial to the enrichment of organic matter and lead to the formation of high levels of sapropelite and exinite.According to the variation of oil and gas components in the pyrolysis experiments,the hydrocarbon generation process is divided into three stages:kerogen cracking,oil cracking and C2-5 cracking.Combined with hydrocarbon generation characteristics and stages,the evolutionary model of hydrocarbon generation for source rocks under different environments is established.
文摘Dongpu depression is a fault basin at residual-mobility period of Diwa stage, it developed on the strata of the Mesozoie and Pre-Mesozoie. It is one of the important oil/gas- bearing basin during Cenozoie era along the East China. The strueture in Dongpu geodepression is very complex. There exists a strueture pattern with east- and west-depression belts and one central swell belt, it is divided into the southern- and northern-division by Gaopingji (orMeng Ju ) -Xieheng fault.
文摘Data from the super-deep wells (PS10, PS14 and YS1) led to the discovery of widespread metal-bearing hydrothermal fluids (or hot brines ) related to basic magrmas in the Lower Tertiary clastic sequence in the Dongpu Depression. In terms of SEM and EDAX analyses, pore-casting thin asction examination of sandstone, the composition and forming temperature of fluld inclusions, the trace element composition of mudstone and kerogen and organic geochemical analyses, it is demonstrated that the hydrothermal fluids ekisting in the area studied are ejecting fluids, which have a close bearing on diagenesis and edimentation, rather than intrusive veins along the tectonic fractures.The main indicators of hydrothermal activity are: (1 ) abnormal alteration of kerogen, (2)high-temperature alteted mineral assemblage; (3) abnormal distribution of hydrocarbons; (4) specific assemblages and abnormal contents of heavy metals in mudstone and kerogen; (5) specific composition of complex compounds and assemblages of fluid inclusions in sandstone: (6) periodic basaltic magma activity.Results of geological observations and laboratory simuating experiments demonstrated that the hydrothermal fluids have a close bearing on hydrocarbon generation in the Dongpu Depression. Two aspects of the effect of hydrothermal fluids are noticed: hydrothermal hydrocarbon production and strong metal catalysis in oil and gas generation.
文摘Fission track analysis can provide important information of paleotemperatures and its temporal change, and is a very favourable method to solve geothermal problems in fine spacetime scale. According to the determination of apatite fission track ages and length, the annealing characteristics of apatite fission track, geothermal evolution and prediction of petroleum source in studied area are discussed.
