岚M1-1煤层气多分支水平井充气钻井技术

为开采煤层气提高煤气产量,设计钻探了岚M1-1煤层气多分支水平井,该井煤层气储量大,埋深在900 m处左右。钻进时,先钻一口直井并在煤层段造洞穴,在距200 m处钻一口水平井,水平段连通洞穴,再在水平段上对称侧钻出10个分支井眼。钻进中,采用欠平衡钻井技术,直井眼充气,钻井液与气体在洞穴处混合,形成负压钻井。直井和水平井的上直段采用钟摆钻具组合。水平井的主井眼和分支井眼均采用导向钻具组合、无线测量技术,井壁稳定技术采用高黏度钻井液。造洞穴采用液压伸臂式扩眼器,水平井上直井段500 m处打悬塞,直井洞穴上部悬挂?127 mm割孔尾管进行完井。结果为,总进尺7993 m,生产时效100%,全井组平均机械转速8.69 m/h,锻铣造洞穴成功率100%,水平井与洞穴直井一次连通,悬空侧钻分支一次成功率100%,电测一次成功率100%,完井一次成功率100%。结果表明,岚M1-1多分支水平井工艺技术先进,10个分支数量在国内最多,控制面积在国内最大,为今后国内煤层气井钻进技术提供了宝贵的经验。

TECHNOLOGY OF DRILLING MIXED WITH GAS FOR LAN M1-1 COALBED GAS MULTI-BRANCH HORIZONTAL WELL

To increase output of coalbed gas well,we have designed and drilled Lan M1-1 coalbed gas multi-branch horizontal well.With a large coalbed gas reserves,the buried depth is about 900 m.When it was being drilled,a vertical well was drilled at first,and caves were made in coalbed gas sect,then a horizontal well were drilled at a distance of 200 m,horizontal segment were in connection with the caves,and 10 branch holes were lateral drilled symmetrically in horizontal sect.Underbalance technology were taken by us during drilling,vertical hole was filled with gas,drilling fluid were mixed with gas in caves,and negative pressure drilling technology was formed.Pendulum assembly was used in vertical well and upper vertical segment of horizontal well.Steering assembly and MWD and LWD were used in main holes and branch holes of horizontal well.High viscosity drilling fluid was used for stabilizing borehole wall.Hydraulic reamer was used for making caves,and plugging at the distance of 500 m in upper vertical segment of horizontal well.A ?127mm slotted liner was hanged above vertical well cave to complete the well.The result is,total footage is 7993 m,production percentage is 100,the average mechanical rotating speed of the whole well is 8.69 m/h,percentage for making caves in segment by milling is 100, horizontal well was connected with caves only one times.Percentage for branch by impending lateral drilling in one time is 100,percentage for electric logging is 100,percentage for well completion in one time is 100.The result show that the technology for Lan M1-1 multi-branch horizontal well is advanced,and the amount of branches with 10 is the maximum in domestic market,the controlling area is the biggest in domestic market,which will provide valuable experience for domestic coalbed gas drilling in future.