四川盆地上二叠统龙潭组深-超深部煤层气资源开发潜力  

Potential for the production of deep to ultradeep coalbed methane resources in the Upper Permian Longtan Formation,Sichuan Basin

作　　者：明盈 孙豪飞 汤达祯[2] 徐亮 张本健 陈骁[1] 徐唱 王嘉先 陈世达[2] MING Ying;SUN Haofei;TANG Dazhen;XU Liang;ZHANG Benjian;CHEN Xiao;XU Chang;WANG Jiaxian;CHEN Shida(Exploration and Development Research Institute,Southwest Oil&Gas Field Company,PetroChina,Chengdu 610041,China;School of Energy Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国石油西南油气田分公司勘探开发研究院,四川成都610041 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《煤田地质与勘探》2024年第2期102-112,共11页Coal Geology & Exploration

基　　金：国家自然科学基金项目(42130802)。

摘　　要：准噶尔盆地彩南地区、鄂尔多斯盆地东缘大宁-吉县和延川南区块1000~2500 m埋深煤层气井实现高产气流突破,昭示了深部煤层气开发的巨大潜能。四川盆地上二叠统龙潭组薄-中厚煤层群(7~15层)主体埋深2000~4500 m,川中一带北倾单斜,局部发育低幅隆起,煤层含气量、含气饱和度、储层压力等开发关键参数均优于浅部,具备支持“增储上产”国家天然气发展战略的强大潜力。研究表明:(1)龙潭组煤系煤-泥岩互层频繁,煤层多,累计资源量大,19号煤层侧向发育稳定(平均3.2 m;>4 m有利面积700 km^(2));(2)煤的热演化程度高(2.53%~3.18%),生烃能力强,煤系气测全烃显示良好,2500 m埋深处实测含气量16.64~17.61 m^(3)/t,含气饱和度达138%~151%,游离气含量4.84~5.60 m^(3)/t;(3)川南800 m以深实测储层压力系数>1.1,川中一带预测储层压力系数>1.8,为潜在的异常超高压储层。立足四川盆地煤层深-超深部、超压、超饱和等资源禀赋特征,借鉴鄂尔多斯盆地东缘大宁一带深部煤层气成功经验,以19号煤层为风险勘探目标,落实资源潜力和气藏特征,探索构建深-超深部薄煤层立体勘探开发技术体系,对煤层气规模化建产意义重大。Breakthroughs have been achieved in the high-yield gas flow of coalbed methane(CBM)wells with burial depths ranging from 1000 to 2500 m in the Cainan area of the Junggar Basin and the Daning-Jixian and southern Yanchuan blocks on the eastern margin of the Ordos Basin,signifying the enormous potential for the production of deep CBM.In the Sichuan Basin,the thin to moderately thick coal seam groups(7‒15 layers)in the Upper Permian Longtan Formation primarily exhibit burial depths ranging between 2000 and 4500 m.In the central Sichuan Basin,characterized by north-dipping monoclines and local low-amplitude uplifts,deep coal seams display superior critical production parameters,including gas content,gas saturation,and reservoir pressure,to shallow ones,demonstrating considerable potential for supporting China’s natural gas development strategy of reserve growth and production addition.Key findings are as follows:(1)The Longtan Formation coal measures manifest frequent coal-mudstone interbeds,a large number of coal seams,and huge cumulative resources.Notably,the No.19 coal seam is well-developed laterally,with an average thickness of 3.2 m and a favorable area(thickness:>4 m)of 700 km^(2).(2)The high thermal maturity(2.53%‒3.18%)of coals suggest a high hydrocarbon generation capacity.The gas logging-derived total hydrocarbon value of coal measures reveals favorable results,with measured gas content,gas saturation,and free gas content at a burial depth of 2500 m varying in ranges of 16.64‒17.61 m^(3)/t,138%‒151%,and 4.84‒5.60 m^(3)/t,respectively.(3)The reservoirs at a burial depth exceeding 800 m in the southern Sichuan Basin exhibit measured pressure coefficients of above 1.1,and those in the central Sichuan Basin display predicted pressure coefficients of above 1.8,indicating potential abnormally ultra-high pressure reservoirs.Based on the deep to ultradeep,overpressure,and supersaturated resource endowment characteristics of coal seams in the Sichuan Basin and referencing the successful experience in dee

关 键 词：四川盆地 深-超深部 煤层气 储层特性 资源潜力 

分 类 号：TE132[石油与天然气工程—油气勘探]