四川盆地渝西大安区块龙潭组深层煤岩气压裂技术探索  

Fracturing technologies for Longtan Formation deep coal-rock gas in Da'an Block of western Chongqing,Sichuan Basin

作　　者：李德旗 陈钊 邹清腾 龚舒婷 刘臣 王天一 赖建林 葛婧楠 江铭 潘丹丹 刘兆然 曹博文 LI Deqi;CHEN Zhao;ZOU Qingteng;GONG Shuting;LIU Chen;WANG Tianyi;LAI Jianlin;GE Jingnan;JIANG Ming;PAN Dandan;LIU Zhaoran;CAO Bowen(PetroChina Zhejiang Oilfield Company,Hangzhou,Zhejiang 310023,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Jinzhou Oil Production Plant,PetroChina Liaohe Oilfield Company,Jinzhou,Liaoning 121000,China;CNPC Engineering Technology R&D Company Limited,Tianjin 300450,China)

机构地区：[1]中国石油浙江油田公司,浙江省杭州市310023 [2]中国石油勘探开发研究院 [3]中国石油辽河油田公司锦州采油厂 [4]中国石油工程技术研究有限公司

出　　处：《天然气工业》2024年第10期150-158,共9页Natural Gas Industry

基　　金：中国石油天然气集团有限公司科技项目“非常规储层改造关键技术研究——页岩气复杂防控及高效压裂技术与试验”(编号:2023ZZ28-05)。

摘　　要：据多轮次煤层气资源评价结果,沉积于海陆交互环境的四川盆地上二叠统龙潭组也是重要的产煤层系,其中作为南方首个浅层山地煤层气代表的川南地区筠连煤层气田已成功实现商业开发,而深层煤岩气勘探评价仍处于探索试验阶段,亟需结合深层煤岩的构造和储层特征,建立一套适用于深层煤岩气的压裂技术体系。为此,从储层物性、岩石力学、顶底板特征3个方面,对比分析了四川盆地渝西区块龙潭组19号煤岩与其他深层煤岩气的地质工程差异,通过正交试验优化压裂参数,形成了“小簇间距布缝(15~23 m)+单段多簇射孔(4簇)+大排量大规模造缝(施工排量18~20 m^(3)/min、用液强度32~35 m^(3)/m)+高强度加砂支撑(6.5~7.0 t/m)”的压裂工艺技术,成功实施了四川盆地首口深层煤岩气水平井的压裂作业。研究结果表明:①龙潭组深层煤岩煤质呈软塑性,割理和裂缝发育,需通过小簇间距布缝、大排量大规模造缝、高强度加砂支撑的压裂工艺思路以提高缝网复杂程度和支撑裂缝导流能力;②微注入压降测试(DFIT)获取的地质参数与测井资料预测的数据吻合度好,在深层煤岩具有良好的适用性;③针对深层煤岩具有高孔隙度、发育割理和裂隙的地质特征,停泵30 min+投球暂堵的方式可以有效提高改造范围和效果。结论认为,在四川盆地渝西大安区块深层煤岩气的探索实践,有助于形成深层煤岩气压裂改造技术体系,对加快推进四川盆地超压、超饱和深层龙潭组煤岩气高效规模开发具有重要的指导意义。Multiple rounds of coalbed methane(CBM)resource assessments suggest that the Longtan Formation in the Sichuan Basin which is deposited in a marine-continental interactive environment is also a significant coal producing stratum.As the first shallow mountain coalbed methane site in the southern China,the Junlian Coalbed Methane Field in the southern Sichuan Basin has achieved a commercial development.However,the exploration and evaluation of deep coal-rock gas is still in an exploration and trial stage.Therefore,it is in an urgent need to establish a set of fracturing technology system suitable for deep coal-rock gas based on the structural and reservoir characteristics of deep coal rocks.In this paper,the geological and engineering differences between the No.19 coal seam of Longtan Formation in the western Chongqing of Sichuan Basin and other deep coal-rock gas are comparatively analyzed from the aspects of reservoir physical properties,rock mechanics,and roof and floor characteristics.In addition,the fracturing parameters are optimized on the basis of orthogonal experiment,and the fracturing technological process of"fracture arrangement at small cluster spacing(15-23 m)+single-stage multi-cluster perforating(4 cluster)+large-displacement and large-scale fracturing(construction displacement:18-20 m^(3)/min,fracturing fluid intensity:32-35 m^(3)/m)"+high-intensity sand addition(6.5-7.0 t/m)is formed.Thus the fracturing of the first deep coal-rock gas horizontal well in the Sichuan Basin is implemented successfully.The following results are obtained.First,the deep coal rocks of the Longtan Formation are soft and plastic with developed cleats and fractures,so it is necessary to adopt the fracturing process ideas of fracture arrangement at small cluster spacing,large-displacement large-scale fracturing,and high-intensity sand addition so as to improve the fracture network complexity and support the fracture conductivity.Second,the geological parameters derived from micro-injection pressure drop test(DFIT)align closel

关 键 词：四川盆地 渝西大安区块 龙潭组 深层煤岩气 压裂改造 正交试验 暂堵转向 

分 类 号：TE37[石油与天然气工程—油气田开发工程]