八角场气田煤型气藏的成藏过程研究

Research on gas accumulation process of coal-formed gas pool in Bajiaochang gas field

通过对八角场气田煤系地层研究发现 ,岩石中的有机包裹体大部分都充填在石英颗粒内的溶蚀孔或溶蚀缝中 ,石英次生加大边极少见 ,构造裂缝中没有包裹体。有机包裹体大小一般小于 5μm ,而且大多低于 3μm ,其丰度一般低于 5 % ,主要为气态烃 +盐水溶液二相和气态烃相。包裹体均一温度主峰在 10 0～ 12 0℃。自生伊利石形成年龄分布为 111～ 118Ma。香四段气藏的油气注入过程开始于中侏罗世晚期—晚侏罗世早期 ,早白垩世形成了大量包裹体 ,晚白垩世—喜山期包裹体的形成逐渐停止 ,自生伊利石停止生长。根据流体包裹体均一温度及自生伊利石年龄的分布 。

The author researched the reservoir diagenesis and organic inclusion in the reservoir,Bajiaochang gas field.In this area,the fluid inclusions distributed chiefly in dissolved seams and pores in quartz grains and not in secondary quartz margin and structure slot.Their diameter was under 0.5μm,the abundance was not up to 5% their phases had chiefly gaseous hydrocarbon adding brine and single gaseous hydrocarbon and their homogenization temperature peak was between 100～120℃.In the forth interval gas reservoir of Xiangxi Group,gas charge started from late period of the Middle Jurassic and a large number of fluid inclusions were formed in the accumulation was formed from the Upper Cretaceous to Xishan Epoch when the formation stopped gradually.