石灰沟地区上石炭统煤系气源岩生气潜力分析

柴达木盆地东缘石灰沟地区上石炭统克鲁克组含煤岩系地层厚度大,分布范围广,具备煤系气资源形成的条件。煤系烃源岩全区分布,矿区中部最厚,以岩性组合特征将克鲁克组划分为四段,总体有机质丰度较高,但克1段有机质丰度较其他三段略差。克鲁克组烃源岩以Ⅱ型干酪根为主,部分为Ⅲ型,且全段均无差异地表现为成熟–高成熟演化程度的特征。以底界埋深、泥岩累计厚度、灰岩累计厚度等有效信息圈定了研究区石炭系克鲁克组煤系气发育优选区,即CY井以西地区。

Gas potential analysis of upper carboniferous coal-measure gas source rocks in Shihuigou area

The upper Carboniferous Keluke formation coal-bearing rock series in Shihuigou area, eastern margin of Qaidam basin is characterized by large thickness and wide distribution, and possesses the conditions for the formation of coal-bearing gas resources. The coal measure hydrocarbon source rocks are distributed in the whole area, and the middle part of the mine is the thickest. According to the lithologic assemblage characteristics, the Keluke formation is divided into four sections. The organic matter abundance of the whole section is higher, but the organic matter abundance of the first section is slightly worse than that of the other three sections. The hydrocarbon source rocks in Keluke formation is given priority to typeⅡ kerogen, part of them are typeⅢ, and all segments showed no difference in maturity-high maturity evolution degree. Based on the effective information of bottom boundary burial depth, mudstone cumulative thickness and limestone cumulative thickness, this paper delineates the optimum area for coal measures gas development of Carboniferous Keluke formation in the study area, that is to say the area west of CY well.