Deep coalbed methane enrichment rules and its exploration and development prospect in Linxing block

Linxing block is located in the eastern margin of the Ordos basin,crossing Jinxi flexural fold belts and Yis- han slope area. In the block,some faults were developed in eastern part,the formation is gentle in western part,and the intrusive rock of Zijin Mountain exists in middle part. The enrichment of coalbed methane is controlled by construc- tion,maturity and hydrogeological condition. High grade of maturity indicates that a large amount of hydrocarbon was generated in coal. In the late period,the coalbed methane reservoir was destroyed by construction,however the forma- tion water retention is beneficial to keep coalbed methane. Gas content distributes high in west and low in east. In Zijin Mountain,which is located in the middle,the annular gas content high value zone and low value zone were formed by hydrothermal process and fault destructive effect. Within the zone,gas content is controlled by mature grade generally, but it disagrees with the gas content total regularity, because there is a gas content high value window (1 600-2 000 m) in the middle part of study zone. In the block,the micropore was developed in coal,pore difference is small, structure is relatively uniform,total diffusivity and permeability are great. Overall,the evaluation shows that the coalbed methane in the block is a large quantity of resource with high abundance,high gas saturation and great physical prop- erties. Therefore,this block have the potential for a further pilot test.