下辽河盆地东部凹陷古近系沙河街组页岩气成藏条件分析及资源量计算

在分析录井、钻井及地球化学等资料的基础上,对辽河盆地东部凹陷沙河街组页岩气成藏地质条件进行研究。东部凹陷沙河街组富有机质泥岩主要为沉积于半深湖-深湖的暗色泥岩及发育在沼泽环境中的炭质泥岩,分布面积为3 000 km~2,有机碳丰度为1%~16.97%,干酪根类型以Ⅱ_1和Ⅱ_2型为主,其有机质镜质体反射率(Ro)整体处于低成熟-高成熟阶段。通过类比美国五大页岩气产区成藏地质条件,笔者预测东部凹陷驾掌寺—二界沟、黄于热地区可评为有利页岩气远景区。利用气测全烃值、孔隙度及吸附气计算总含气量,求得有利远景区在沙三段与沙一、二段页岩气资源量分别为871×10~8m~3和742×10~8m~3。

Analysis of accumulation conditions on Paleogene Shahejie Formation shale gas in eastern sag of Liaohe Basin and calculation of its resource extent

According to the analyses on the logging，drilling and geochemical data，the accumulation geolog- ical conditions of Shahejie Formation shale gas in the eastern sag of Liaohe Basin are studied． The rich organic mat- ter mudstone is mainly the dark mudstone deposited on the half deep lake- deep lake and the charcoal mudstone formed from the swamp environment in Shahejie Formation of the eastern sag，which is 3 000 km 2 in area． The ma- jor organic carbon values of the dark mudstone range from 1% to 16. 97%，and the kerogen types are mainly Ⅱ 1 and Ⅱ 2 ． The vitrinite reflectance values (Ro) of most organic matter at the low- mature and the high- mature stage． Comparing with five shale gas producing areas in United States， the authors forecast that the Jiazhangsi- Erjie- gou area and the Huangyure area in the eastern sag are rated as the beneficial prospective areas of shale gas accu- mulation． Using the relationship among measuring hydrocarbon gas，porosity and sorbed- gas content to get total gas content，the shale gas resource extent of beneficial prospective areas is 871 ×10 8 m 3 in the third member of Shahe- jie Formation and 742 ×10 8 m 3 in the first and the second member of Shahejie Formation．