倾斜煤层煤层气与煤炭地下气化协调开发技术构想

Conception of coordinated development technology system for coalbed methane and underground coal gasification in inclined coal seams

煤层气(CBM)开发与煤炭地下气化(UCG)是我国煤基天然气生产的重要来源,新疆前陆冲断带倾斜煤层发育区煤与煤层气资源丰富。为深入剖析倾斜煤层CBM与UCG协调开发可行性,系统剖析了现有CBM与UCG关键技术及其对CBM−UCG协调开发的借鉴意义,分析了倾斜煤层CBM与UCG协调开发优势、技术路径、面临的主要问题和未来研究方向,得到以下认识:①“CBM开发疏干效应”“UCG热作用解吸效应”“UCG采动卸压效应”下CBM−UCG协调开发可形成相互促进的良性循环;②提出了直井+顺煤层倾向井“先抽后烧”、顺煤层倾向井组合“边抽边烧”、定向L型CBM井+顺煤层倾向UCG井“边烧边抽”、下部煤层布置沿倾向UCG井+上部煤层布置定向L型CBM井“先抽后烧再抽”、复杂井型“井工厂式”布置等协调开发技术路径;③CBM与UCG协调开发面临地质选区评价理论基础研究薄弱、缝网条件下UCG热作用扩展范围不清、倾斜煤层UCG过程岩层移动卸压范围不明等理论问题;同时面临CBM−UCG协调开发“井工厂式”钻井技术、CBM井与UCG井协调开发生产制度、CBM与UCG协调开发地质动态测控、CBM井密封性与耐高温性保护等工程问题;④要强化倾斜煤层CBM与UCG协调开发地质选址评价研究、开发动态理论研究、工程协调技术先导性试验研究,确保协调开发安全、有序、可控、高效。

Coalbed methane(CBM)development and underground coal gasification(UCG)are important sources for coal-based natural gas production in China,and coal and CBM resources are abundant in the inclined coalbed development area of the Xinjiang foreland thrust belt.To deeply analyze the feasibility of coordinated development of CBM and UCG in inclined coal seams,the existing key techno-logies of CBM and UCG and their significances for coordinated development of CBM-UCG was systematically analyzed,the advantages,the technical routes,major problems and future research directions of coordinated development of CBM and UCG in inclined coal seams were also elaborated,the major problems faced and the direction of future research were proposed,and the following understanding was obtained.①The coordinated development of CBM-UCG under the“CBM development dredging effect”,“UCG thermal desorption ef-fect”,and“UCG mining pressure releasing effect”can form a virtuous cycle of mutual promotion.②The coordinated development tech-nology routes was proposed,such as vertical wells+inclined well along coal seam with“first drainage and then gasification”,multiple in-clined wells along the coal seam with“simultaneous drainage and gasification”,directional L-typed CBM wells+UCG wells along the coal seam direction with“simultaneous gasification and drainage”,UCG wells along inclined wells in the lower coal+directional L-typed CBM wells in the upper coal seam with“first drainage,then gasification,and then drainage again”,and the“well factory”arrangement of complex well type.③The coordinated development of CBM and UCG faces theoretical issues such as weak theoretical foundation re-search on geological constituency evaluation,unclear expansion range of UCG thermal action under the condition of fracture network,and the undetermined range of rock movement and pressure relief in the UCG process of inclined coal seams.It also faces the engineering is-sues such as coordinated development of CBM-UCG“well factory”drilling technology,coordinated development of CBM wells and UCG wells production system,coordinated development of CBM and UCG wells geodynamic measurement and control,and the sealing and high-temperature-resistant protection of CBM wells.④It is necessary to strengthen the study on the evaluation of geological site selection for the coordinated development of CBM and UCG in inclined coal seams,the theoretical research on the development dynamics,and the pioneering experimental study on engineering coordination technology,so as to ensure that the coordinated development is safe,orderly,controllable and efficient.