准噶尔盆地白家海凸起深部含煤层气系统储层组合特征

Characteristics of reservoir assemblage of deep CBM-bearing system in Baijiahai dome of Junggar Basin

准噶尔盆地东部白家海凸起发育较稳定的侏罗系煤层,埋深大于1 500 m。以往该区西山窑组和八道湾组煤层气试采取得了较好的效果,显示了白家海凸起深层煤层气具有较好的勘探前景。由于区内以常规油气开发为主,丰富的煤层气资源有待勘探开发。基于此,分析了区内侏罗系深部煤层赋存特征、热演化程度、煤层含气量及煤层顶底围岩等成藏地质条件,认为西山窑组煤层气为独立含煤层气系统,八道湾组煤层及其顶底砂岩组合为统一含煤层气系统。八道湾组源内型、源外型含煤层气系统成藏条件优越,煤层气及煤系砂岩气资源丰富,具有较大的共采潜力。

Coal seams in Jurassic Xishanyao and Badaowan Formation were developed well in the Baijiahai dome of Junggar Basin.The burial depth of main coalbed is more than 1 500 m. Over the past ten years,the pre-production of several conventional oil and gas wells in coal seams had obtained good results,the volume of coalbed methane were more than 7 000 m3,which shows a good deep coalbed methane exploration prospect in Baijiahai dome.The amount of coalbed methane resources remains to be developed in Cainan oilfield.Based on the in-depth analysis of deep coalbed distribution characteristics,coal thermal evolution degree,the distribution of gas content and adjacent formation,it is considered that the Xishanyao coalbed is an independent CBM-bearing system,and the combination of Badaowan coalbed and its adjacent sandstone is another CBM-bearing system. The superior accumulation conditions of the innersource type and outside source type of Badaowan CBM-bearing system are enriched in CBM and sandstone gas resources,both two have a potential in commingled production.