松辽盆地梨树断陷苏家屯次洼页岩气成藏条件分析

通过对松辽盆地梨树断陷苏家屯次洼基本油气地质特征分析,认为营城组一段形成于断陷发育的鼎盛时期,发育稳定的大套泥岩夹薄砂岩地层.地化特征表明该段泥页岩具有有机质丰度较好、有机质类型丰富、热演化处于生气的成熟—高成熟阶段等特点.泥页岩中平均孔隙度达到3.52%,裂缝和微裂缝相对较发育,不仅可以为游离态气提供有利的储集空间,且脆性矿物含量相对较高,平均为41.1%,石英含量在15.1%~23.4%之间,岩石具有较好的可压性.钻井现场解析结果表明该段泥页岩中含气最高可达3.09 m3/t,且钻井气测全烃异常以及测试资料也表明该区页岩气的存在,说明该泥页岩中蕴藏着一定规模的页岩气资源,具有良好的资源前景和勘探潜力. 

Accumulation conditions of shale gas in Sujiatun Sub-depression, Lishu Fault Depression, Songliao Basin

The geologic features of the Sujiatun Sub-depression in the Lishu Fault Depression indicated that during the heyday of fault depression development,a large set of mudstone interbedded with sandstone generated stably in the first member of the Yingcheng Formation.This set of shale is characterized by rich organic content,various organic types and is mature and high-mature for gas generation.The average porosity is 3.52% and a mass of fractures can be observed,providing room for free gas accumulation.In addition,the content of brittle minerals is relatively higher,with an average value of 41.1%.The content of quartz ranges from 15.1% to 23.4%.The shale is easy to crack.Field works have shown that the highest gas content in the shale may amount to 3.09 m3/t.The abnormity in total hydrocarbon measuring also predicts the existence of shale gas,indicating for good potential.