济阳坳陷生物成因页岩气藏形成条件探析——以惠民凹陷阳信洼陷为例

济阳坳陷在阳信洼陷沙一段首次发现生物成因气,其源岩为同层段广泛发育的一套暗色泥页岩。为了摸清该套泥页岩是否具备形成生物成因页岩气藏的条件,对该套泥页岩的"生、储、保"等条件进行了系统分析。研究表明:该套泥页岩埋藏浅,厚度大,分布广泛,正处于生物气生烃高峰时期,地化分析指标相对于北美富气页岩均在有利的范围以内,泥页岩中脆性矿物含量高,微孔隙和微裂缝较发育,夹有砂岩和碳酸盐岩薄层,处于有利的构造背景。综合分析认为,该套泥页岩具备形成生物成因页岩气藏的条件,预示着济阳坳陷在生物成因页岩气勘探方面具有较好的前景。

Analysis on Biogenic Shale Gas Reservoir Forming Conditions in Jiyang Depression: a Case Study from Yangxin Subsag , Huimin sag

In Jiyang depression the biogenic gas was first found from the first member of Shahejie Formation in Yangxin Subsag, and it came from a set of well-developed dark mud shales at the same layers. In order to know whether the mud shales have the conditions of forming biogenic shale gas, the conditions of source-reservoir-preservation were anatomized. The results show that the mud shales are at the stage of high hydrocarbon generation, with the characteristics of shallow burial, large thickness, wide distribution, appropriate geochemical analysis parameters as well as America gas-rich shales, well developed micropores and microfractures, some sandstone and carbonate thin-interlayers, better tectonic background, and so on. According to the results, the mud shales have the conditions of forming biogenic shale gas, so it means a good prospect for biogenic shale gas exploration in Jiyang depression.