鄂尔多斯盆地苏里格气田深层煤层气直井压裂实践与认识  

Practice and understanding of vertical well fracturing for deep CBM reservoirs in Sulige gasfield,Ordos Basin

作　　者：谢宾 曾凌翔 李彬 陈星宇 XIE Bin;ZENG Lingxiang;LI Bin;CHEN Xingyu(CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610051,China;CCDC Downhole Service Company,Chengdu,Sichuan 610051,China)

机构地区：[1]中国石油川庆钻探工程有限公司,四川成都610051 [2]中国石油川庆钻探工程有限公司井下作业公司,四川成都610051

出　　处：《天然气勘探与开发》2024年第6期45-52,共8页Natural Gas Exploration and Development

基　　金：“十三五”国家科技重大专项(编号:2016ZX05062-05)。

摘　　要：目前深层(埋深3000 m以深)煤层气勘探开发处于起步阶段,深层煤物性特征认识、储层改造工艺匹配等问题制约了深层煤层气的规模勘探开发。针对其储层埋深大、压力高、温度高、游离气高、滤失量大、压后单一水力裂缝等特点,提炼前期改造工艺优势,优化压裂参数,升级压裂液性能,支撑三级裂缝,增能低压储层,达到“打碎储层、沟通割理、控制滤失、高效支撑、提高改造体积”的目的。优选勘探A井区作为先导试验现场,初步建立一套适用于本区域大排量大规模煤层气压裂改造工艺。应用结果表明:(1)运用“前置高黏压裂液建主缝+低黏压裂液建缝网+支撑三级裂缝+液氮增能”改造工艺,压后返排率达到86.2%;(2)大排量、极限加砂、短射孔段+少簇数、多粒径组合支撑剂沟通主缝+分支缝+割理微裂隙,多手段构建有效长支撑缝网;(3)压后水力裂缝延伸较好,呈现双向展布裂缝,水力裂缝长度约380 m,与最大主应力走向基本一致,改造面积约7.2×10^(4)m^(2)。研究成果对深层煤层气压裂现场应用具有借鉴意义。Currently,deep(˃3000 m)coalbed methane(CBM)exploration and development are in the initial stages.Issues in understanding the physical properties of deep coal and matching reservoir stimulation processes have constrained the large-scale exploration and development of deep CBM.Considering the characteristics of CBM reservoirs,including deep burial,high pressure,high temperature,high free gas,large filtration loss,and post-frac single hydraulic fracture,a set of large-scale and-discharge fracturing process suitable for such CBM reservoirs was preliminarily established by extracting the advantages of previous stimulation treatments,optimizing fracturing parameters,upgrading fracturing fluid performance,supporting tertiary fractures,and energizing low-pressure reservoirs to break reservoirs,connect cleats,control filtration loss,support efficiently,and improve stimulated volume.Field application in a pilot test area,Well A block,shows that,(i)the stimulation with high-viscosity fracturing fluid as ahead fluid to create the main fractures,low-viscosity fracturing fluid to create the fracture network,supporting tertiary fractures,and liquid nitrogen for energy replenishment helps realize the post-frac backflow rate up to 86.2%;(ii)an effective long support fracture network is created by various means including large discharge,extreme sand adding,short perforation section with few clusters,and multiple particle size combination of proppants for connecting main fractures,branch fractures and cleat microfissures;and(iii)the created hydraulic fractures extend well,showing a bidirectional distribution,with the length of about 380 m;the fractures are basically consistent with the trend of the maximum principal stress;and the stimulated area is approximately 7.2×10^(4)m^(2).The research results are referential for the field application of deep CBM reservoir fracturing.

关 键 词：深层 煤层气 压裂 优化 裂缝 实践 

分 类 号：TE377[石油与天然气工程—油气田开发工程]