鄂尔多斯盆地临兴地区上古生界压力特征及其成因机制
|
摘要
查明鄂尔多斯盆地临兴地区上古生界压力特征及其成因可为煤系气运聚和成藏研究奠定基础。根据实测压力资料并结合修正公式,得出临兴地区上古生界石盒子组压力特征。根据声波时差预测剥蚀量的方法,应用Easy%RO模拟软件、实测镜质组反射率得出本溪组8+9号煤层的埋藏史和热史;结合包裹体测温数据和钻测井资料,得出石盒子组古埋深。在此基础上,分别计算出地温降低、欠压实作用、气体逸散及孔隙反弹引起的上古生界石盒子组压力的下降值。结果表明:研究区石盒子组正常压力类型占23%,低压类型占73%,超压仅占4%;早白垩世末期地层压力达到最大;地层剥蚀导致地温下降引起的压力下降为7.9～17.3MPa,占整个压力降幅的40%～55%;欠压实作用引起的压力下降为1.81～2.24MPa,占压力降幅的7%～11%;气体逸散引起的压力下降为7.61～11.99MPa,占压力降幅的34%～42%;孔隙反弹引起的压力下降为1.68～1.95MPa,占压力降幅的6.40%～6.68%。砂岩气量与压力系数之间呈正相关关系。该研究成果为该区石盒子组压力系统研究奠定了基础。
Finding out the formation pressure characteristics and genesis of Upper Paleozoic in Linxing area of Ordos Basin can lay a foundation for the study of coal measures gas migration and accumulation.Based on the actual measured pressure data and the revised formula,the formation pressure characteristics of Shihezi Formation of Upper Paleozoic in Linxing area are obtained.According to the method of predicting the amount of denudation by acoustic time difference,by using Easy%ROsimulation software and the measured vitrinite reflectance,the burial history and thermal history of the No.8+9 coal seam of Benxi Formation are obtained.Combined with the data of inclusions analyses and the drilling log,the pressure drop of the Upper Paleozoic Shihezi Formation caused by the decrease of ground temperature,under-compaction,gas escape and pore rebound was calculated.The results show that the normal pressure type of the Shihezi Formation in the study area accounts for 23%,the low pressure type accounts for 73%,the overpressure only accounts for 4%,and the formation pressure reached the maximum at the end of the Early Cretaceous;The pressure drop caused by formation denudation is 7.9-17.3 MPa,which accounts for 40%-55%of the whole pressure drop;the pressure drop caused by under-compaction is 1.81-2.24 MPa,which accounts for 7%-11% of the pressure drop;the pressure drop caused by gas escape is 7.61-11.99 MPa,which accounts for 34%-42%of the pressure drop;and the pressure drop caused by pore rebound is 1.68-1.95 MPa,which accounts for 6.40%-6.68% of the pressure drop.There is a positive correlation between sandstone gas volume and pressure coefficient.The research results laid a foundation for the study of the pressure system of the Shihezi Formation in this area.
Finding out the formation pressure characteristics and genesis of Upper Paleozoic in Linxing area of Ordos Basin can lay a foundation for the study of coal measures gas migration and accumulation.Based on the actual measured pressure data and the revised formula,the formation pressure characteristics of Shihezi Formation of Upper Paleozoic in Linxing area are obtained.According to the method of predicting the amount of denudation by acoustic time difference,by using Easy%ROsimulation software and the measured vitrinite reflectance,the burial history and thermal history of the No.8+9 coal seam of Benxi Formation are obtained.Combined with the data of inclusions analyses and the drilling log,the pressure drop of the Upper Paleozoic Shihezi Formation caused by the decrease of ground temperature,under-compaction,gas escape and pore rebound was calculated.The results show that the normal pressure type of the Shihezi Formation in the study area accounts for 23%,the low pressure type accounts for 73%,the overpressure only accounts for 4%,and the formation pressure reached the maximum at the end of the Early Cretaceous;The pressure drop caused by formation denudation is 7.9-17.3 MPa,which accounts for 40%-55%of the whole pressure drop;the pressure drop caused by under-compaction is 1.81-2.24 MPa,which accounts for 7%-11% of the pressure drop;the pressure drop caused by gas escape is 7.61-11.99 MPa,which accounts for 34%-42%of the pressure drop;and the pressure drop caused by pore rebound is 1.68-1.95 MPa,which accounts for 6.40%-6.68% of the pressure drop.There is a positive correlation between sandstone gas volume and pressure coefficient.The research results laid a foundation for the study of the pressure system of the Shihezi Formation in this area.
引文
[1]Wu Xuanyu.Characteristics and Factors Analysis of Influence of Formation Pressure Level on Low Permeability Reservoir Production[D].Xi’an:Xi’an Shiyou University,2017:8-17.吴轩宇.地层压力保持水平对低渗油藏产量影响特征及因素分析[D].西安:西安石油大学,2017:8-17.
[2]Zhang Jinliang,Zhang Jingong,Hong Feng,et al.Geologic controls of deep basin gas sccumulations in the Lower Permian sequence of the Ordos Basin[J].Nature Gas Geoscience,2005,16(4):526-534.张金亮,张金功,洪峰,等.鄂尔多斯盆地下二叠统深盆气藏形成的地质条件[J].天然气地球科学,2005,16(4):526-534.
[3]Zhang Liuping,Luo Xiaorong,Ma Xinhuan,et al.From deep basin gas to diagenetic trap:An example from the Yulin Gas Field in the Ordos Basin[J].Chinese Science Bulletin,2007,52(21):2973-2983.
[4]Wang Xiaomei,Zhao Jingzhou,Liu Xinshe,et al.Current distribution characteristics and genesis of the Upper Paleozoic in the eastern Ordos Basin[J].Oil&Gas Geology,2013,34(5):646-651.王晓梅,赵靖舟,刘新社,等.鄂尔多斯盆地东部上古生界现今地层压力分布特征及成因[J].石油与天然气地质,2013,34(5):646-651.
[5]Zhang Wenzhong.Study on the Genesis of Subnormal Formation Pressure in the Upper Paleozoic Strata of Sulige Gasfield[D].Beijing:China University of Geosciences,2009:111-115.张文忠.苏里格地区上古生界气田异常低压成因研究[D].北京:中国地质大学,2009:111-115.
[6]Chen Ruiyin,Luo Xiaorong,Chen Zhankun,et al.Restoration of burial history of four periods in Ordos Basin[J].Acta Petrolei Sinica,2006,27(2):43-47.陈瑞银,罗晓容,陈占坤,等.鄂尔多斯盆地埋藏演化史恢复[J].石油学报,2006,27(2):43-47.
[7]Weng Wangfei,Liu Chiyang,Zhao Hongge,et al.Denudation thickness restoration of Early Cretaceous strata in the Ordos Basin[J].Journal of Stratigraphy,2009,33(4):373-381.翁望飞,刘池洋,赵红格,等.鄂尔多斯盆地早白垩世剥蚀地层厚度恢复研究[J].地层学杂志,2009,33(4):373-381.
[8]Bumham A K,Sweeney J J.A chemical kinetic model of vitrinite maturation and reflectance[J].Geochemica et Cosmochemica,1989,53(2):2649-2657.
[9]Tao Chuanqi,Wang Yanbin,Ni Xiaoming,et al.The key period of coal-bearing gas accumulation in the Benxi Formation of the Upper Carboniferous in Linxing area[J].Journal of China University of Mining&Technology,2018,47(3):1-7.陶传奇,王延斌,倪小明,等.临兴地区上石炭统本溪组煤系气成藏关键时期[J].中国矿业大学学报,2018,47(3):1-7.
[10]Li Yunqing,He Peng,Wang Jincheng.Investigation on equation of state for hydrocarbon fuel at subcritical and supercritical conditions[J].Chemical Engineering of Oil&Gas,2007,36(1):1-3,17,89.李云清,何鹏,王金成.碳氢燃料在亚临界及超临界状态下的状态方程研究[J].石油与天然气化工,2007,36(1):1-3,17,89.
[11]Mao Cui,Chen Yong,Zhou Yaoqi,et al.Improved simulation method of petroleum inclusions thermodynamic and its application in hydrocarbon accumulations[J].Journal of Jilin University:Earth Science Edition,2015,45(5):1352-1364.毛毳,陈勇,周瑶琪,等.改进后的烃类流体包裹体热力学模拟方法及其在油气成藏研究中的应用[J].吉林大学学报:地球科学版,2015,45(5):1352-1364.
[12]Wang Xin,Jiang Youlu,Cao Lanzhu,et al.Evolution characteristics and influencing factors of paleo-pressure in the gully area of the oil-rich depression:A case study of the Raoyang Sag in the Bozhong depression[J].Journal of China University of Mining&Technology,2017,46(3):586-595.王鑫,蒋有录,曹兰柱,等.富油凹陷洼槽区古压力演化特征及影响因素---以冀中坳陷饶阳凹陷为例[J].中国矿业大学学报,2017,46(3):586-595.
[13]Zhang Y G,Frantz J D.Determination of the homogenization temperatures and densities of supercritical fluids in the system NaCl-KCl-CaCl2-H2O using synthetic fluid inclusions[J].Chemical Geology,1987,64(3-4):335-350.
[14]Fu Guang,Lv Yanfang,Yang Mian.Quantitative study on abnormal pore fluid pressure in undercompacted mudstone[J].Xinjiang Petroleum Geology,2002,23(4):265-266,295-298.付广,吕延防,杨勉.欠压实泥岩异常孔隙流体压力的定量研究[J].新疆石油地质,2002,23(4):295-298,265-266.
[2]Zhang Jinliang,Zhang Jingong,Hong Feng,et al.Geologic controls of deep basin gas sccumulations in the Lower Permian sequence of the Ordos Basin[J].Nature Gas Geoscience,2005,16(4):526-534.张金亮,张金功,洪峰,等.鄂尔多斯盆地下二叠统深盆气藏形成的地质条件[J].天然气地球科学,2005,16(4):526-534.
[3]Zhang Liuping,Luo Xiaorong,Ma Xinhuan,et al.From deep basin gas to diagenetic trap:An example from the Yulin Gas Field in the Ordos Basin[J].Chinese Science Bulletin,2007,52(21):2973-2983.
[4]Wang Xiaomei,Zhao Jingzhou,Liu Xinshe,et al.Current distribution characteristics and genesis of the Upper Paleozoic in the eastern Ordos Basin[J].Oil&Gas Geology,2013,34(5):646-651.王晓梅,赵靖舟,刘新社,等.鄂尔多斯盆地东部上古生界现今地层压力分布特征及成因[J].石油与天然气地质,2013,34(5):646-651.
[5]Zhang Wenzhong.Study on the Genesis of Subnormal Formation Pressure in the Upper Paleozoic Strata of Sulige Gasfield[D].Beijing:China University of Geosciences,2009:111-115.张文忠.苏里格地区上古生界气田异常低压成因研究[D].北京:中国地质大学,2009:111-115.
[6]Chen Ruiyin,Luo Xiaorong,Chen Zhankun,et al.Restoration of burial history of four periods in Ordos Basin[J].Acta Petrolei Sinica,2006,27(2):43-47.陈瑞银,罗晓容,陈占坤,等.鄂尔多斯盆地埋藏演化史恢复[J].石油学报,2006,27(2):43-47.
[7]Weng Wangfei,Liu Chiyang,Zhao Hongge,et al.Denudation thickness restoration of Early Cretaceous strata in the Ordos Basin[J].Journal of Stratigraphy,2009,33(4):373-381.翁望飞,刘池洋,赵红格,等.鄂尔多斯盆地早白垩世剥蚀地层厚度恢复研究[J].地层学杂志,2009,33(4):373-381.
[8]Bumham A K,Sweeney J J.A chemical kinetic model of vitrinite maturation and reflectance[J].Geochemica et Cosmochemica,1989,53(2):2649-2657.
[9]Tao Chuanqi,Wang Yanbin,Ni Xiaoming,et al.The key period of coal-bearing gas accumulation in the Benxi Formation of the Upper Carboniferous in Linxing area[J].Journal of China University of Mining&Technology,2018,47(3):1-7.陶传奇,王延斌,倪小明,等.临兴地区上石炭统本溪组煤系气成藏关键时期[J].中国矿业大学学报,2018,47(3):1-7.
[10]Li Yunqing,He Peng,Wang Jincheng.Investigation on equation of state for hydrocarbon fuel at subcritical and supercritical conditions[J].Chemical Engineering of Oil&Gas,2007,36(1):1-3,17,89.李云清,何鹏,王金成.碳氢燃料在亚临界及超临界状态下的状态方程研究[J].石油与天然气化工,2007,36(1):1-3,17,89.
[11]Mao Cui,Chen Yong,Zhou Yaoqi,et al.Improved simulation method of petroleum inclusions thermodynamic and its application in hydrocarbon accumulations[J].Journal of Jilin University:Earth Science Edition,2015,45(5):1352-1364.毛毳,陈勇,周瑶琪,等.改进后的烃类流体包裹体热力学模拟方法及其在油气成藏研究中的应用[J].吉林大学学报:地球科学版,2015,45(5):1352-1364.
[12]Wang Xin,Jiang Youlu,Cao Lanzhu,et al.Evolution characteristics and influencing factors of paleo-pressure in the gully area of the oil-rich depression:A case study of the Raoyang Sag in the Bozhong depression[J].Journal of China University of Mining&Technology,2017,46(3):586-595.王鑫,蒋有录,曹兰柱,等.富油凹陷洼槽区古压力演化特征及影响因素---以冀中坳陷饶阳凹陷为例[J].中国矿业大学学报,2017,46(3):586-595.
[13]Zhang Y G,Frantz J D.Determination of the homogenization temperatures and densities of supercritical fluids in the system NaCl-KCl-CaCl2-H2O using synthetic fluid inclusions[J].Chemical Geology,1987,64(3-4):335-350.
[14]Fu Guang,Lv Yanfang,Yang Mian.Quantitative study on abnormal pore fluid pressure in undercompacted mudstone[J].Xinjiang Petroleum Geology,2002,23(4):265-266,295-298.付广,吕延防,杨勉.欠压实泥岩异常孔隙流体压力的定量研究[J].新疆石油地质,2002,23(4):295-298,265-266.