沁水盆地煤层气提速钻井液体系设计与性能评价

由于山西沁水盆地地层的复杂性,常常钻遇易漏、易卡地层,钻井事故频发,会造成钻井周期长,钻井效益低,这极大地阻碍了中海油进军煤层气勘探开发的脚步。为解决煤层气钻井的提速增效问题,本文针对煤层气钻井的技术特点,根据现场钻井的地质、钻井资料的分析,首先对地区岩样进行了矿物成分与化学分析,以此为基础设计了两套煤层气提速钻井液体系配方,并进行了室内性能评价,最终获得了煤层气提速钻井液组成为絮凝剂、渗透剂、防泥包剂和抑制剂,优选出絮凝剂聚丙烯酰胺PLUS和聚铝PAC,渗透剂和防泥包剂JFC,抑制剂氯化钾,推荐煤层气提速钻井液配方为:配浆水+0.01%PAC+0.5%JFC+2%~3%KCl,此外通过防漏堵漏分析,针对沁水盆地渗透性漏失,推荐采用0.5%PLUS+3%~5%QWY来进行堵漏。上述技术成果在现场两口井进行了应用,取得了较好的提速效果。

Design and performance evaluation of CBM accelerating drilling fluid system in Qinshui basin

Due to the complexity of strata in Qinshui basin, Shanxi Province, drilling often encounters easy leakage and stuck strata, and frequent drilling accidents will result in long drilling cycle and low drilling benefits, which greatly hinders CNOOC’s steps in CBM exploration and development. In order to solve the problems of the CBM drilling rapidly increase,the technical characteristics of coalbed methane drilling, the author of this paper, based on drilling in the field of the analysis of the geological and drilling data, first sample area for the mineral composition and chemical analysis.On this basis, designed the speed for the two sets of CBM drilling fluid formula, and the indoor performance evaluation. Eventually won the accelerated the CBM drilling fluid composition as flocculating agent, penetrating agent,balling agent and the inhibitor, optimized PLUS polyacrylamide flocculant and poly aluminium PAC, penetrating agent and the balling agent JFC, inhibitors potassium chloride.Accelerated the recommended CBM drilling fluid formula is: mixing water+0.01% PAC+0.5 % JFC+2 %~3 % KCl.In addition, through the analysis of the plugging in Qinshui basin permeability loss, 0.5 % PLUS + 3 %~5 % QWY is recommended to leak. The technical achievements mentioned above have been applied in two wells at the site, and good speed-up effect has been obtained.