Abstract: Multi-branch horizontal well is a new drilling technology developed in recent years.The new technology includes under-balance drilling technology,optimum design and control technique of well path,intersection technique between horizontal well and cave well,and making cave technique in coal layer.The technical specifications of the multi-branch well in coal-bed methane(CBM) field,the principles of making cave technique,under-balance drilling techniques and intersection technique were discussed.The design theory and method of well path and well structure were described.The mechanism of multi-branch well in coal-bed methane field was integrated to develop a set of theories and methods for design of multi-branch well and development of coal-bed methane.

Key words: coal bed gas development, multi branch horizontal well, drilling technology, under balance drilling technology, well path, optimum design

摘要： 煤层气多分支水平井工艺主要包括充气欠平衡技术、井眼轨迹优化设计与控制技术、水平井与洞穴井对接技术、煤层造洞穴技术等.系统地论述了煤层气多分支水平井钻井工艺的技术要点以及井身结构和轨迹设计原则和方法,并且详细阐述了造洞穴、U型充气欠平衡和两井连通工艺的原理及程序.提出了煤层气多分支水平井的设计方法和理论,为未来煤层气的高效勘探开发提供了技术参考.

关键词: 煤层气开发, 多分支水平井, 钻井工艺, 欠平衡钻井技术, 井眼轨迹, 优化设计