湘东北拗陷泥盆系海相泥页岩地球化学特征

Geochemical characteristics of the marine facies shale of Devonian in the Xiangdongbei Depression,Hunan,China

页岩是湘东北拗陷主要烃源岩岩石类型。锡矿山组、佘田桥组、棋梓桥组是其主要的烃源岩层。在充分查阅了基础地质资料的基础上,对湘东北拗陷进行了详尽的地质调查并系统地采集了样品,应用了岩石热解、有机碳分析、镜质体反射率等测试方法对湘东北拗陷页岩的地球化学特征进行了研究。结果表明,湘东北泥盆系佘田桥组、棋梓桥组海相泥页岩厚度较大,分布较广,有机质丰度较好,整体上属于较好烃源岩;有机质类型也比较好,以Ⅱ2型为主,含有部分Ⅱ1型;成熟度已进入成熟期,是有效页岩气气源岩。

The shale is the main rock type of source rock in Xiangdongbei Depression. The main source rocks include Xikuangshan Formation, Shetianqiao Formation and Qiziqiao Formation. On the basis of a lot of basic geologic data, the geology investigation was done and the rocks were sampled for the Depression. The geochemical characteristics of the source rock in Xiangdongbei Depression were studied by the rock pyrolysis, organic carbon analysis and vitrinite reflectance. The results show that the marine facies mud shale of the Shetianqiao Formation and Qiziqiao Formation are thick, widely distributed, with higher abundance of organic matter and belong to good source rocks on the whole. The type of the organic matter is good, the main are Ⅱ1, include Ⅱ2, their thermal maturity stage is at maturity stage. They are effective gas source rock.