China United Coalbed Methane Corporation Ltd. Gas Control and Coalbed Methane Development Cooperation Project Group of Qiyuan Mine,China United Coalbed Methane Corporation Ltd.

为了有效避免煤储层垮塌,减小对煤储层污染程度,提高煤层气短水平段径向钻井压裂技术开发效果。在沁水盆地北部七元矿区块应用短水平段径向分支钻井技术,该径向钻井压裂技术将煤层分为n个施工层位,每个施工层位均钻进4个短水平段径向分支,同一施工层位相邻径向分支的方位角相差π/2,相邻施工层位对应径向分支的方位角相差π/(2n),水平段径向分支长度约为100 m,钻进过程中采用清水高压喷射的方式钻进,钻进结束后对各个施工层位的径向分支进行整体合压。结果表明,该技术能使煤层气井见气时间缩短、产气量较高,并能有效沟通煤层天然裂隙,增大煤层泄气面积,降低煤储层污染程度,避免煤储层垮塌,可为煤层气开发提供一条新的有效增产途径。

in order to effectively avoid a coal reservoir cllapsed,to reduce the pallition degree to the coal reservoir and to improve the develoment efect of the coalbed methane short horizontal section redial drlling and fracturing fechnology.the shor hoizonal redia mutl branch fillig techmnoiogy was applied to aijuan MiningArea the norh part of cinshuiBasi .The radial rlling and fracturing fechrology could divide the seanm into construction unis and each construction layer all could drill 4 short horizontal radial branches. in a same construcion layer.an azinuth dfferenceof the adjacent radial ranches would be Tm/2 and the adjacent construcion layer would have an azinuth ditference of m( 2n) to the relevant radial tranch.The length ofthe horzontal section radial branch was about 100 m. During the drling process.a clean water igh prssure jet method was appied to thedrlling.Afer the drling completed.an integrated compound fracturing was conducted on the radial branchof each construction layer.Th site application results showed that the technology could make a shor time to have a gas production of the calbed methane,o have a hgh gas production.could effictively conmect the natural racks of the seam.could enlarge the gas drainage reaof the seam.could reduce the polution degree of thecoal reservoi.could avoid the colapse of the coal reservoir and could provide a new efctive production increased path to the coalbed methane development.

国家科技重大专项资助项目(2011ZX05042-001)；