研究珠江口盆地HZ26-6构造“双古”领域油气成藏期次和油气成藏条件,探讨油气成藏特点与富集规律。在借鉴前人研究成果的基础上,通过铸体薄片鉴定、包裹体均一温度测定等手段,厘清了HZ26-6构造“双古”领域三大油气主力成藏期及对应的...研究珠江口盆地HZ26-6构造“双古”领域油气成藏期次和油气成藏条件,探讨油气成藏特点与富集规律。在借鉴前人研究成果的基础上,通过铸体薄片鉴定、包裹体均一温度测定等手段,厘清了HZ26-6构造“双古”领域三大油气主力成藏期及对应的流体充注类型,即13.8~10 Ma B.P.的低熟原油充注期,10~5.3 Ma B.P.的成熟原油充注期,5.3 Ma B.P.以来的天然气充注期;依据实际的地质、钻井、测井、地震等资料梳理了HZ26-6构造“双古”领域三大油气成藏关键条件,即以“早期低熟缓慢生油,晚期高熟快速生气”为特点的烃源条件,以“裂缝带风化叠加改造成储,转换带砂砾岩体规模成储”为特征的储层条件,以“通源断裂多期跨层输导,深缝浅砂侧向差异运移”为特征的输导条件。HZ26-6构造“双古”领域具有“早油晚气,宽窗强供;扇加潜山,规模储集;断缝断砂,高效输导;递进充注,整装成藏”的油气成藏特点,以及“油型盆地早油晚气条件下,宽窗强势供烃、‘双古’整装成藏”的油气富集规律。展开更多
By means of thin section analysis, zircon U-Pb dating, scanning electron microscopy, electron probe, laser micro carbon and oxygen isotope analysis, the lithologic features, diagenetic environment evolution and contro...By means of thin section analysis, zircon U-Pb dating, scanning electron microscopy, electron probe, laser micro carbon and oxygen isotope analysis, the lithologic features, diagenetic environment evolution and controlling factors of the tight sandstone reservoirs in the Huagang Formation of Xihu sag, East China Sea Basin were comprehensively studied. The results show that: the sandstones of the Huagang Formation in the central inverted structural belt are poor in physical properties, dominated by feldspathic lithic quartz sandstone, high in quartz content, low in matrix, kaolinite and cement contents, and coarse in clastic grains;the acidic diagenetic environment formed by organic acids and meteoric water is vital for the formation of secondary pores in the reservoirs;and the development and distribution of the higher quality reservoirs in the tight sandstones of the Huagang Formation are controlled by sediment source, sedimentary facies belt, abnormal overpressure and diagenetic environment evolution. Sediment provenance and dominant sedimentary facies led to favorable initial physical properties of the sandstones in the Huagang Formation, which is the prerequisite for development of reservoirs with better quality later. Abnormal high pressure protected the primary pores, thus improving physical properties of the reservoirs in the Huagang Formation. Longitudinally, due to the difference in diagenetic environment evolution, the high-quality reservoirs in the Huagang Formation are concentrated in the sections formed in acidic diagenetic environment. Laterally, the high-quality reservoirs are concentrated in the lower section of the Huagang Formation with abnormal high pressure in the middle-northern part;but concentrated in the upper section of Huagang Formation shallower in burial depth in the middle-southern part.展开更多
Objective The natural gas exploration of the Sinian reservoirs in the central Sichuan Basin has made a significant breakthrough in recent years, and has thus attracted much attention among geologists. The Sichuan Bas...Objective The natural gas exploration of the Sinian reservoirs in the central Sichuan Basin has made a significant breakthrough in recent years, and has thus attracted much attention among geologists. The Sichuan Basin is known to have complicated geological settings, which has experienced multiple stages of tectonic evolution, fluid charging and hydrocarbon accumulation. This research aims to determine the geochemical characteristics of each stage of fluids, the features and time interval of fluid activity in different geologic periods, and further to restore the critical period and geological age of the hydrocarbon accumulation.展开更多
In the Xihu Sag,the reservoirs of the Paleogene Huagang formation have entered the middle diagenetic stage A and the rock physical properties of the water layer are considerably more suitable for the gas migration and...In the Xihu Sag,the reservoirs of the Paleogene Huagang formation have entered the middle diagenetic stage A and the rock physical properties of the water layer are considerably more suitable for the gas migration and storage than those of the present gas layer,indicating the inversion of the physical properties.In this study,core samples were collected from the corresponding reservoir to conduct water-rock reaction experiments in acidic,alkaline,and neutral systems under the specific temperature and pressure.The reasons for the inversion of physical properties were investigated based on the experiment results in reservoir diagenetic environments.The inversion of physical properties can be attributed to the fact that the diagenetic environment around the gas-water interface controls the water-rock reaction effect.With different types of acidic substances,two different situations corresponding to inverted physical properties were analyzed along with the corresponding mechanisms.When the pore fluid is acidic,the physical properties make the overall water layer a better reservoir space than the gas layer,which can be referred to as the overall inversion of physical properties.When the fluid were generally neutral or weakly alkaline and the gas layer was rich in CO2,only the physical properties of the water layer adjacent to the gas-water interface were more favorable for the gas migration than those of the gas layer.This phenomenon can be referred to as the near-interface inversion of physical properties.展开更多
Paleosalinity is vital for the paleoenvironmental reconstruction and affects the formation of source rock.The lower-middle sections of the third member of Eocene Shahejie formation(Es3M-L)constitute the most important...Paleosalinity is vital for the paleoenvironmental reconstruction and affects the formation of source rock.The lower-middle sections of the third member of Eocene Shahejie formation(Es3M-L)constitute the most important source rock layer in Laizhou Bay Sag.However,the paleosalinity of the depositional water in which Es3M-L submembers are deposited remains unclear.A series of integrated experiments,including major and trace elements,X-ray diffraction,total organic carbon,and Rock-Eval,was performed to reveal the paleosalinity and its relationship with organic matter(OM).Various inorganic proxies(Sr/Ba,Rb/K,B/Ga,Walker’s paleosalimeter,Adam’s paleosalimeter,and Couch’s paleosalimeter)were employed to determine the paleosalinity of samples.Prominent differences existed in the proxies.Couch’s paleosalimeter is the most reliable and qualitative approach for Laizhou Bay Sag.Samples from the lake center(depocenter)and margin showed paleosalinities from 4.92 wt‰to 9.73 wt‰,suggesting a ubiquitous brackish(oligohaline-mesohaline)water body in the paleolake.Molybdenum enrichment in samples indicates an oxygen-depleted(suboxic or anoxic)condition.The increase in salinity has a certain but non-significant positive correlation with oxygen reduction.This condition may be attributed to the weak stratification of the water column in brackish water bodies.Moreover,paleosalinity has a weak and indirect relationship with OM accumulation during the deposition of Es3M-L submembers in Laizhou Bay Sag.展开更多
The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature t...The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature testing of fluid inclusions, Laser Raman composition analysis and isotope geochemical analysis. The Cambrian Longwangmiao Formation in the study area went through 5 stages of fluid charging, in which 3 stages, mid-late Triassic, early-mid Jurassic and early-mid Cretaceous, were related to oil and gas charging. Especially the oil and gas charging event in early-mid Cretaceous was the critical period of gas accumulation in the study area, and was recorded by methane gas inclusions in the late stage quartz fillings. The ^(40) Ar-^(39) Ar dating of the 3 rd stage methane inclusions shows that the natural gas charging of this stage was from 125.8±8.2 Ma. Analysis of Si, O isotopes and ^(87) Sr/^(86) Sr of the late stage quartz indicates that the fluid source of the quartz was formation water coming from long term evolution and concentration of meteoric water, but not from deep part or other sources, this also reflects that, in the critical charging period of natural gas, the Cambrian Longwangmiao Formation in Moxi structure had favorable conservation conditions for hydrocarbon accumulation, which was favorable for the formation of the Longwangmiao large natural gas pool.展开更多
Objective Bitumen is generally associated with oil and gas, which was originally used as an indicator of hydrocarbon reservoirs. With the progress of organic geochemical measuring and testing techniques, bitumen, esp...Objective Bitumen is generally associated with oil and gas, which was originally used as an indicator of hydrocarbon reservoirs. With the progress of organic geochemical measuring and testing techniques, bitumen, especially solid bitumen sampled from reservoirs, has been proved to be closely related to the evolution of hydrocarbon reservoirs. The Sinian cores collected from the Anyue gas field contain abundant pores, vugs and fractures, which are filled with a mass of solid bitumen of two epochs and dolomite in between. This work focused on the characteristics of different generations of bitumen and the genesis, in an effort to better understand the process of the Sinian gas accumulation in the Anyue gas field.展开更多
文摘研究珠江口盆地HZ26-6构造“双古”领域油气成藏期次和油气成藏条件,探讨油气成藏特点与富集规律。在借鉴前人研究成果的基础上,通过铸体薄片鉴定、包裹体均一温度测定等手段,厘清了HZ26-6构造“双古”领域三大油气主力成藏期及对应的流体充注类型,即13.8~10 Ma B.P.的低熟原油充注期,10~5.3 Ma B.P.的成熟原油充注期,5.3 Ma B.P.以来的天然气充注期;依据实际的地质、钻井、测井、地震等资料梳理了HZ26-6构造“双古”领域三大油气成藏关键条件,即以“早期低熟缓慢生油,晚期高熟快速生气”为特点的烃源条件,以“裂缝带风化叠加改造成储,转换带砂砾岩体规模成储”为特征的储层条件,以“通源断裂多期跨层输导,深缝浅砂侧向差异运移”为特征的输导条件。HZ26-6构造“双古”领域具有“早油晚气,宽窗强供;扇加潜山,规模储集;断缝断砂,高效输导;递进充注,整装成藏”的油气成藏特点,以及“油型盆地早油晚气条件下,宽窗强势供烃、‘双古’整装成藏”的油气富集规律。
基金Supported by the China National Science and Technology Major Project(2016ZX05027-002-006).
文摘By means of thin section analysis, zircon U-Pb dating, scanning electron microscopy, electron probe, laser micro carbon and oxygen isotope analysis, the lithologic features, diagenetic environment evolution and controlling factors of the tight sandstone reservoirs in the Huagang Formation of Xihu sag, East China Sea Basin were comprehensively studied. The results show that: the sandstones of the Huagang Formation in the central inverted structural belt are poor in physical properties, dominated by feldspathic lithic quartz sandstone, high in quartz content, low in matrix, kaolinite and cement contents, and coarse in clastic grains;the acidic diagenetic environment formed by organic acids and meteoric water is vital for the formation of secondary pores in the reservoirs;and the development and distribution of the higher quality reservoirs in the tight sandstones of the Huagang Formation are controlled by sediment source, sedimentary facies belt, abnormal overpressure and diagenetic environment evolution. Sediment provenance and dominant sedimentary facies led to favorable initial physical properties of the sandstones in the Huagang Formation, which is the prerequisite for development of reservoirs with better quality later. Abnormal high pressure protected the primary pores, thus improving physical properties of the reservoirs in the Huagang Formation. Longitudinally, due to the difference in diagenetic environment evolution, the high-quality reservoirs in the Huagang Formation are concentrated in the sections formed in acidic diagenetic environment. Laterally, the high-quality reservoirs are concentrated in the lower section of the Huagang Formation with abnormal high pressure in the middle-northern part;but concentrated in the upper section of Huagang Formation shallower in burial depth in the middle-southern part.
基金supported by the Natural Science Foundation of China(grant No.41372141)
文摘Objective The natural gas exploration of the Sinian reservoirs in the central Sichuan Basin has made a significant breakthrough in recent years, and has thus attracted much attention among geologists. The Sichuan Basin is known to have complicated geological settings, which has experienced multiple stages of tectonic evolution, fluid charging and hydrocarbon accumulation. This research aims to determine the geochemical characteristics of each stage of fluids, the features and time interval of fluid activity in different geologic periods, and further to restore the critical period and geological age of the hydrocarbon accumulation.
基金This research was supported financially by the National Key Technology Research and Development Program of China during the‘13th Five-Year Plan’(No.2016ZX05027-002-006).
文摘In the Xihu Sag,the reservoirs of the Paleogene Huagang formation have entered the middle diagenetic stage A and the rock physical properties of the water layer are considerably more suitable for the gas migration and storage than those of the present gas layer,indicating the inversion of the physical properties.In this study,core samples were collected from the corresponding reservoir to conduct water-rock reaction experiments in acidic,alkaline,and neutral systems under the specific temperature and pressure.The reasons for the inversion of physical properties were investigated based on the experiment results in reservoir diagenetic environments.The inversion of physical properties can be attributed to the fact that the diagenetic environment around the gas-water interface controls the water-rock reaction effect.With different types of acidic substances,two different situations corresponding to inverted physical properties were analyzed along with the corresponding mechanisms.When the pore fluid is acidic,the physical properties make the overall water layer a better reservoir space than the gas layer,which can be referred to as the overall inversion of physical properties.When the fluid were generally neutral or weakly alkaline and the gas layer was rich in CO2,only the physical properties of the water layer adjacent to the gas-water interface were more favorable for the gas migration than those of the gas layer.This phenomenon can be referred to as the near-interface inversion of physical properties.
基金This study was supported by grants from the National Science and Technology Major Projects(No.2016ZX05024-002-007)the CNOOC Project(No.CCL2020TJ X0NST1271).
文摘Paleosalinity is vital for the paleoenvironmental reconstruction and affects the formation of source rock.The lower-middle sections of the third member of Eocene Shahejie formation(Es3M-L)constitute the most important source rock layer in Laizhou Bay Sag.However,the paleosalinity of the depositional water in which Es3M-L submembers are deposited remains unclear.A series of integrated experiments,including major and trace elements,X-ray diffraction,total organic carbon,and Rock-Eval,was performed to reveal the paleosalinity and its relationship with organic matter(OM).Various inorganic proxies(Sr/Ba,Rb/K,B/Ga,Walker’s paleosalimeter,Adam’s paleosalimeter,and Couch’s paleosalimeter)were employed to determine the paleosalinity of samples.Prominent differences existed in the proxies.Couch’s paleosalimeter is the most reliable and qualitative approach for Laizhou Bay Sag.Samples from the lake center(depocenter)and margin showed paleosalinities from 4.92 wt‰to 9.73 wt‰,suggesting a ubiquitous brackish(oligohaline-mesohaline)water body in the paleolake.Molybdenum enrichment in samples indicates an oxygen-depleted(suboxic or anoxic)condition.The increase in salinity has a certain but non-significant positive correlation with oxygen reduction.This condition may be attributed to the weak stratification of the water column in brackish water bodies.Moreover,paleosalinity has a weak and indirect relationship with OM accumulation during the deposition of Es3M-L submembers in Laizhou Bay Sag.
基金Supported by the National Natural Science Foundation of China(41572133,41372141)
文摘The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature testing of fluid inclusions, Laser Raman composition analysis and isotope geochemical analysis. The Cambrian Longwangmiao Formation in the study area went through 5 stages of fluid charging, in which 3 stages, mid-late Triassic, early-mid Jurassic and early-mid Cretaceous, were related to oil and gas charging. Especially the oil and gas charging event in early-mid Cretaceous was the critical period of gas accumulation in the study area, and was recorded by methane gas inclusions in the late stage quartz fillings. The ^(40) Ar-^(39) Ar dating of the 3 rd stage methane inclusions shows that the natural gas charging of this stage was from 125.8±8.2 Ma. Analysis of Si, O isotopes and ^(87) Sr/^(86) Sr of the late stage quartz indicates that the fluid source of the quartz was formation water coming from long term evolution and concentration of meteoric water, but not from deep part or other sources, this also reflects that, in the critical charging period of natural gas, the Cambrian Longwangmiao Formation in Moxi structure had favorable conservation conditions for hydrocarbon accumulation, which was favorable for the formation of the Longwangmiao large natural gas pool.
基金supported by the National Natural Science Foundation of China(grant No.41572133)National Key Basic Research and Development Project (grant No.2012CB214805)
文摘Objective Bitumen is generally associated with oil and gas, which was originally used as an indicator of hydrocarbon reservoirs. With the progress of organic geochemical measuring and testing techniques, bitumen, especially solid bitumen sampled from reservoirs, has been proved to be closely related to the evolution of hydrocarbon reservoirs. The Sinian cores collected from the Anyue gas field contain abundant pores, vugs and fractures, which are filled with a mass of solid bitumen of two epochs and dolomite in between. This work focused on the characteristics of different generations of bitumen and the genesis, in an effort to better understand the process of the Sinian gas accumulation in the Anyue gas field.