The Distribution Rules of Gas in Shan 2 Member in Yulin Area of Changqing Gas Field

Yulin area of Changqing gas field in Ordos basin has the favorable conditions for gas accumulation in Shan 2 Member, which is the main productive layer to increase reserve and production. Based on the research of gas pool forming conditions, the distribution rules of gas in Shan 2 Member in Yulin area of Changqing gas field can be concluded: coals, swap dark mudstones and delta front sandbodies are well-developed vertically, the conditions of reservoir-forming combination for self-generation and self-preservation are processed; the sandbodies developed in submerged distributary channel and mouth bar microfacies of delta front have a high content of quartz, which have a good physical properties and a high gas production. There is a good relationship between the distribution of gas pools and the maturity of sandstone, the value 6 of maturity index (86% quartz content) can be used to delineate the zones of gas enrichment and productivity. This rule can guide the exploration and production of this area in next step.