川东石炭系气藏含气系统研究

从含气系统研究思路和方法出发,详细研究了川东地区石炭系气藏的生烃子系统、运移子系统和捕集子系统.石炭系气藏天然气主要来自下伏的志留系生油(气)岩,也有部分来自上覆的阳新统.川东地区志留系-石炭系含气系统的充注能力较强,其生烃潜力指数值较高;含气系统的持续时间从早志留世到早白垩世,而其保存时间从晚白垩世一直至今.志留系烃源岩排烃为垂向排烃,是通过压力封存箱的破裂而产生的混相涌流完成的.油气二次运移的排烃是通过流体对流实现的.川东地区石炭系气藏属于箱外成藏.气藏的成藏类型有:①低覆压准散失型常压气藏;②中覆压富(满)集型常压气藏;③高覆压富集型常压气藏.

A STUDY ON GAS SYSTEM OF CARBONIFEROUS GAS POOLS IN EAST SICHUAN BASIN

Generative sub system,migration sub system and entrapment sub system of the gas system of Carboniferous gas pool in east Sichuan Basin has been studied by the method and thought of gas system.Carboniferous gas was mainly from Silurian source rock in east Sichuan Basin.Silurian Carboniferous gas system has high ability to be filled(with high SPI value).The primary migration of hydrocarbon in Silurian Carboniferous gas system from the Silurian abnormal pressured fluid compartments is a pressure driven process in which the hydrocarbon moved vertically into the normal pressured Carboniferous carbonate through the broken boundaries of Silurian abnormal pressured fluid compartments.The secondary migration of hydrocarbon in Silurian Carboniferous gas system was complete depending on fluid convection.There are three formation modes of Carboniferous gas pools in east Sichuan Basin.They are low overlain pressure para lost pools with normal pressure;middle overlain pressured abundant(full)gas pools with normal pressure;high overlain pressured abundant gas pools with normal pressure.Besides,there are high overlain pressured independent water pools with abnormal high pressure in east Sichuan Basin.