Comprehensive Evaluation on Middle and Upper Devonian Source Rocks in Lianyuan Depression in Hunan Province

Thickness of Middle-upper Devonian hydrocarbon source rocks in Lianyuan Depression was above 500m, and it was widely distributed. According to the research of hydrocarbon source rocks (outcrops), together with interior testing results of bottom fluid, the comprehensive evaluation was conducted on Middle-upper Devonian hydrocarbon source rocks in Lianyuan Depression. The evaluation included the distribution and types of source rocks, and types, abundance and maturity of organic materials. The results show that the abundance of organic materials in source rocks is relatively high, and types of organic materials are mainly type I and type Ⅱ. The degree of thermal evolution of organic material in Lianyuan Depression is relatively high, but it is different in different layers or areas. Middle-upper Devonian organic materials are at post mature stage and methane gas is in dominant position.