川东北飞仙关组异常压力演化与油气成藏  

EVOLUTION OF ABNORMAL PRESSURE AND HYDROCARBON ACCUMULATION IN FEIXIANGUAN FORMATION IN THE NORTHEASTERN SICHUAN BASIN

作　　者：过敏[1] 李仲东[1] 杨磊[1] 张健[2] 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.成都理工大学,四川成都610059 [2]中国石油西南油气田分公司,四川成都610051

出　　处：《西南石油大学学报（自然科学版）》2010年第1期175-182,207,共8页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家重点基础研究发展规划"973"项目(2002CB211705)

摘　　要：根据实测的下三叠统飞仙关组地层压力资料所展示的地层压力分布与气藏的特征关系,分析了不同类型储层气藏压力成因机制、演化及与油气成藏关系。正常压力系统,多处于台地边缘礁滩相,储层岩性以云岩为主,储集类型多为孔隙型,气藏一般甲烷含量低、硫化氢含量高;异常高压或超高压系统,多处于海槽区或台内云岩欠发育区,储层岩性以灰岩为主,气藏甲烷含量高、不含或含极少量的硫化氢,主要为裂缝型气藏;孔隙型气藏和裂缝型气藏具有明显不同的成压演化机制:以孔隙型储层为主的气藏经历了印支末期—燕山早期古油藏常压阶段,燕山中—晚期液态烃类热裂解成气的超压气藏阶段,TSR反应及其作用和喜马拉雅期的构造抬升使孔隙型储层降压为正常压力系统并最终定型为常压气藏阶段;以裂缝型储层为主气藏经历了燕山中—晚期高压天然气充注和燕山晚期构造挤压作用下古高压气藏阶段,喜马拉雅晚期强烈构造挤压超高压气藏定型阶段。According to the relations between the distribution of the formation pressure and the characteristics of gas reservoir,which is showed by pressure data measured in Feixianguan Formation,reservoir pressure genetic mechanism,evolution and the relationship of hydrocarbon accumulation of various gas pools are analyzed.Normal pressure systems always develop in reef-bank complex on carbonate platform margin,most of reservoir rocks are dolostone,the main reservoir type is pore-type,and gas pools are always low in methane and high in hydrogen sulfide.Abnormal high pressure or extra high pressure system appears constantly in ocean trough section or inside platform where lacks dolostone,reservoir rocks are dominated by limestone,and the main gas pool is fractured gas reservoir with high methane content,exclude or include very small amount of hydrogen sulfide.To development of pressure in fractured reservoirs and porous reservoirs,there is different evolutional mechanism,porous reservoirs experienced the stage of normal pressure in Late Indo-Chinese epoch-Early Yanshan movement,and went through the stage of abnormal pressure which was formed by liquid hydrocarbon cracking into gas in Mid-Late Yanshan movement,TSR reaction and function along with uplift shaped in Himalayan movement made the porous reservoir pressure reduce into normal stress system,and fall into a pattern with normal gas reservoir pressure.Fractured reservoirs experienced high-pressure formed by hydrocarbon-charging in Mid-Late Yanshanian movement,and experienced high-pressure gas reservoir phase which was generated by structural compression function in Late Yanshanian movement,the stage of extra high pressure gas reservoir stereotyped by strong extrusion tectonics in late Himalayan.

关 键 词：飞仙关组 碳酸盐岩 压力分布 成压机制 构造 演化 川东北 压力异常 

分 类 号：TE122[石油与天然气工程—油气勘探]