延川南气田近薄层煤层气开发实践及其示范意义  

Development practice of near-thin bed CBM in the Yanchuannan gas field and its demonstration significance

作　　者：杨松[1] 刘晓[1] 申建[2] 陈贞龙[1] 崔彬[1] 张国林 张文洪[1] YANG Song;LIU Xiao;SHEN Jian;CHEN Zhenlong;CUI Bin;ZHANG Guolin;ZHANG Wenlong(Sinopec Linfen CBM Company,Linfen,Shanxi 041000,China;MOE Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process//China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国石化临汾煤层气分公司 [2]煤层气资源与成藏过程教育部重点实验室·中国矿业大学

出　　处：《天然气工业》2023年第8期90-97,共8页Natural Gas Industry

基　　金：国家自然科学基金项目“高温水热驰豫过程中低阶煤储层解耦特征与机理”(编号:42072191)、“深部煤层气赋存态调整分配及释放产出机制”(编号:42272195);中国石油化工股份有限公司科技项目“低压煤系气藏地质工程一体化高效开发关键技术研究”(编号:P20074-1)。

摘　　要：鄂尔多斯盆地东缘延川南气田自2013年启动产能建设以来,下二叠统山西组2号煤层已累计生产天然气23.3×10^(8)m^(3),实践重复压裂、氮气泡沫洗井等开发措施后,气田仅能保持天然气产量稳定。为保障气田的高效开发,聚焦该区2号煤层下伏的上石炭统太原组的近薄10号煤层(煤层发育厚度不足2 m),通过对比10号和2号两套煤层含气性、渗透性和可压性的差异,查明了10号煤层地质—工程条件,分析了增效压裂后裂缝形态和产气效果,形成了近薄层煤层气的勘探理论和开发技术。研究结果表明:(1)10号煤埋藏深、变质程度高、镜质组含量高、灰分产率低、生气潜力大;(2)10号煤吸附能力强,顶底板封隔性好、含水性弱,滞留水环境有利于煤层气保存,含气量高达44 m^(3)/t,资源基础好;(3)10号煤心割理更发育,水平应力差异系数大,压裂易形成主裂缝且不易突破顶底板,成缝效率更高,可压性更好;(4)增效压裂能“横向”延伸储层缝长以弥补“纵向”厚度不足、提高储量动用程度,应用后天然气提产效果显著。结论认为,延川南气田近薄层煤层气的开发实践,坚持从地质条件和开发工艺两方面出发,形成了针对于近薄煤层的开发关键技术,为延川南气田的天然气长期稳产明确了方向,为我国沁水盆地、楚雄盆地等多层叠置煤层气藏中的近薄层煤层气开发提供了新的启示。Since the Yanchuannan gas field at the eastern margin of the Ordos Basin started to produce in 2013,No.2 coal seam of the Lower Permian Shanxi Formation has produced 23.3×10^(8) m^(3) natural gas cumulatively.After the implementation of development measures such as refracturing and nitrogen foam flushing,the gas field can only keep stable natural gas production.In order to ensure the efficient development of the Yanchuannan gas field,this paper focuses on the"near-thin"No.10 coal seam(thickness<2 m)of Upper Carboniferous Taiyuan Formation underlying No.2 coal seam,and figures out the geological-engineering conditions of No.10 coalbed methane(CBM)by comparing No.10 and No.2 coal seams in terms of gas content,permeability and fracturability.In addition,the fracture morphology and gas production effect after enhanced fracturing are analyzed,and the exploration theory and development technology of near-thin bed CBM are developed.The following research results are obtained.First,No.10 coal seam is deep and highly metamorphic,with high vitrinite content,low ash content and great gas generation potential.Second,No.10 coal seam has strong adsorption capacity,and its roof and floor have a good sealing property and weak water content.Water retention environment is conducive to CBM preservation,with gas content up to 44 m^(3)/t,providing a good resource basis.Third,the cleat in the core of No.10 coal seam is more developed,and the horizontal stress difference coefficient is large.Therefore,fracturing can hardly break through the roof and floor while easily inducing main fractures,so as to achieve higher fracturing formation efficiency and better fracturability.Fourth,the formation of enhanced fracturing can extend the reservoir fracture length"laterally"to make up for the insufficient"vertical"thickness and improve the recovery efficiency.After the application of this understanding,natural gas production is improved remarkably.In conclusion,in the development practice of near-thin bed CBM in the Yanchuannan gas field,the k

关 键 词：延川南气田 煤层气 近薄层 地质条件 储层改造 增效压裂 开发实践 

分 类 号：TE37[石油与天然气工程—油气田开发工程]