沈北煤田空气造穴工艺的技术探讨

Analysis of Air-cavity Technology in Shenbei Coal Mine

在国内外煤层气开采中,裸眼洞穴造穴技术主要分为三种:负压造穴、水力射流造穴和机械工具造穴。本文所阐述的是负压造穴技术,也就是空气造穴技术,其方法是采用空气钻或经过特殊改造的钻机,再配备几台大功率的空压机和增压机以及地面管路系统,将大量空气注入井内,通过多次的快速憋压和放喷作业,造成剧烈的井内压力激动,使煤层崩落形成洞穴,实现井眼与地层之间有效连通而达到增产的目的。

To CBM production,openhole cavity completions include three methods：under-pressure cavity,jetting cavity and mechanical cavity. In this paper,the under pressure cavity technology is discussed which is also called air cavity as well. We use an air rig or a special rig with several compressors,boosters and surface line equipments. This system injects great volume of air into the well to be cavited. After a series of injections and blowdowns were performed,coal fails and sloughs into the wellbore,leading to created a cave. The conductivity between reservoir and wellbore was improved,which increase the production of CBM.