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

Analysis of biogenic shale gas reservoir forming conditions in Jiyang depression: A case study from Yangxin subsag,Huimin sag

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。

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 .