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.
作者
李阳
倪小明
王延斌
陶传奇
Li Yang;Ni Xiao-ming;Wang Yan-bing;Tao Chuan-qi(School of Energy Science and Engineering,Henan Polytechnic University jiaozuo 454000;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region Henan Province,Jiaozuo 454000;College of Geo-science and Surveying Engineering China University of Mining & Technology,Beijing 100083,China)
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2019年第7期997-1005,共9页
Natural Gas Geoscience
基金
国家科技重大专项(编号:2016ZX05066001-002)资助
