The gas-water distribution and production heterogeneity of tight gas reservoirs have been summarized from experimental and geological observations, but the charging and accumulation mechanisms have not been examined q...The gas-water distribution and production heterogeneity of tight gas reservoirs have been summarized from experimental and geological observations, but the charging and accumulation mechanisms have not been examined quantitatively by mathematical model. The tight gas charging and accumulation mechanisms were revealed from a combination of physical simulation of nuclear magnetic resonance coupling displacement, numerical simulation considering material and mechanical equilibria, as well as actual geological observation. The results show that gas migrates into tight rocks to preferentially form a gas saturation stabilization zone near the source-reservoir interface. When the gas source is insufficient, gas saturation reduction zone and uncharged zone are formed in sequence from the source-reservoir interface. The better the source rock conditions with more gas expulsion volume and higher overpressure, the thicker the gas saturation stabilization and reduction zones, and the higher the overall gas saturation. When the source rock conditions are limited, the better the tight reservoir conditions with higher porosity and permeability as well as larger pore throat, the thinner the gas saturation stabilization and reduction zones, but the gas saturation is high. The sweet spot of tight gas is developed in the high-quality reservoir near the source rock, which often corresponds to the gas saturation stabilization zone. The numerical simulation results by mathematical model agree well with the physical simulation results by nuclear magnetic resonance coupling displacement, and reasonably explain the gas-water distribution and production pattern of deep reservoirs in the Xujiaweizi fault depression of the Songliao Basin and tight gas reservoirs in the Linxing-Huangfu area of the Ordos Basin.展开更多
Objective As the uplift belt on the southern margin of the Tarim block,the Tiekelike block consists mainly of a set of Precambrian metamorphic rocks with granulite and gneisses.The Heluositan group-complex is the most...Objective As the uplift belt on the southern margin of the Tarim block,the Tiekelike block consists mainly of a set of Precambrian metamorphic rocks with granulite and gneisses.The Heluositan group-complex is the most ancient rock series in the area,and is a key area for studying the formation and evolution of the Precambrian basement of the Tarim craton.LA-ICP-MS zircon展开更多
Based on the microscopic pore-throat characterization of typical continental tight reservoirs in China,such as sandstone of Cretaceous Qingshankou and Quantou formations in Songliao Basin,NE China sandy conglomerate o...Based on the microscopic pore-throat characterization of typical continental tight reservoirs in China,such as sandstone of Cretaceous Qingshankou and Quantou formations in Songliao Basin,NE China sandy conglomerate of Baikouquan Formation in Mahu area and hybrid rock of Lucaogou Formation in Jimusaer sag of Junggar Basin,NE China the theoretical lower limit,oil accumulation lower limit,effective flow lower limit and the upper limit of tight oil reservoirs were defined by water film thickness method,oil bearing occurrence method,oil testing productivity method and mechanical balance method,respectively.Cluster analysis method was used to compare the differences in pore-throat structure of different tight reservoirs,determine the grading criterion of tight reservoirs,and analyze its correlation with the limit of reservoir formation.The results show that the boundary between tight reservoir and conventional reservoir corresponds to the upper limit of physical properties,the boundary of classⅡand classⅢtight reservoirs corresponds to the lower limit of effective flow,the boundary of classⅢand classⅣtight reservoirs corresponds to the lower limit of reservoir forming,and the theoretical lower limit of tight reservoir corresponds to the boundary between tight reservoir and non-reservoir.Finally,the application results of the grading evaluation criterion show that the tight oil productivity is highly controlled by the type of tight reservoir,and classⅠand classⅡtight reservoirs are the favorable sections for high production of tight oil.展开更多
基金Supported by the National Natural Science Foundation of China(42302183,42272156,41922015)Sanya City Science and Technology Innovation Project(2022KJCX51).
文摘The gas-water distribution and production heterogeneity of tight gas reservoirs have been summarized from experimental and geological observations, but the charging and accumulation mechanisms have not been examined quantitatively by mathematical model. The tight gas charging and accumulation mechanisms were revealed from a combination of physical simulation of nuclear magnetic resonance coupling displacement, numerical simulation considering material and mechanical equilibria, as well as actual geological observation. The results show that gas migrates into tight rocks to preferentially form a gas saturation stabilization zone near the source-reservoir interface. When the gas source is insufficient, gas saturation reduction zone and uncharged zone are formed in sequence from the source-reservoir interface. The better the source rock conditions with more gas expulsion volume and higher overpressure, the thicker the gas saturation stabilization and reduction zones, and the higher the overall gas saturation. When the source rock conditions are limited, the better the tight reservoir conditions with higher porosity and permeability as well as larger pore throat, the thinner the gas saturation stabilization and reduction zones, but the gas saturation is high. The sweet spot of tight gas is developed in the high-quality reservoir near the source rock, which often corresponds to the gas saturation stabilization zone. The numerical simulation results by mathematical model agree well with the physical simulation results by nuclear magnetic resonance coupling displacement, and reasonably explain the gas-water distribution and production pattern of deep reservoirs in the Xujiaweizi fault depression of the Songliao Basin and tight gas reservoirs in the Linxing-Huangfu area of the Ordos Basin.
基金supported by Xinjiang Uygur Autonomous Region 1:50000 special funds to support the transfer(grant No.1212011140056)
文摘Objective As the uplift belt on the southern margin of the Tarim block,the Tiekelike block consists mainly of a set of Precambrian metamorphic rocks with granulite and gneisses.The Heluositan group-complex is the most ancient rock series in the area,and is a key area for studying the formation and evolution of the Precambrian basement of the Tarim craton.LA-ICP-MS zircon
基金Supported by the National Science and Technology Major Project(2016ZX05046-001-005)National Natural Science Foundation of China(41922015)。
文摘Based on the microscopic pore-throat characterization of typical continental tight reservoirs in China,such as sandstone of Cretaceous Qingshankou and Quantou formations in Songliao Basin,NE China sandy conglomerate of Baikouquan Formation in Mahu area and hybrid rock of Lucaogou Formation in Jimusaer sag of Junggar Basin,NE China the theoretical lower limit,oil accumulation lower limit,effective flow lower limit and the upper limit of tight oil reservoirs were defined by water film thickness method,oil bearing occurrence method,oil testing productivity method and mechanical balance method,respectively.Cluster analysis method was used to compare the differences in pore-throat structure of different tight reservoirs,determine the grading criterion of tight reservoirs,and analyze its correlation with the limit of reservoir formation.The results show that the boundary between tight reservoir and conventional reservoir corresponds to the upper limit of physical properties,the boundary of classⅡand classⅢtight reservoirs corresponds to the lower limit of effective flow,the boundary of classⅢand classⅣtight reservoirs corresponds to the lower limit of reservoir forming,and the theoretical lower limit of tight reservoir corresponds to the boundary between tight reservoir and non-reservoir.Finally,the application results of the grading evaluation criterion show that the tight oil productivity is highly controlled by the type of tight reservoir,and classⅠand classⅡtight reservoirs are the favorable sections for high production of tight oil.
