青西地区防塌钻井液体系的研究与应用

Research and Application of Anti-Collapse Drilling Fluid in Qingxi Block

陈志学崔柳黎红胜纪国栋毕文欣程荣超

CHEN Zhi-Xue CUI Liu LI Hong-Sheng JI Guo-Dong BI Wen-Xin CHENG Rong-Chao

通过室内X-衍射、钻屑回收率和膨胀率实验，得到青西地区地层黏土矿物分布规律，并建立了黏土矿物剖面。实验结果表明，地层黏土矿物呈M形分布，要求钻井液在上部地层应具备强抑制性，下部应具备封堵防塌能力，为不同井段钻井液性能的维护处理提供了科学依据。针对青西地层岩性特点和钻井液技术难点，结合使用的几种不同钻井液体系情况，开展了抑制剂、降滤失剂和高温稳定剂室内评价，优选出抑制性最强和封堵防塌能力最高的阳离子钻井液体系。其配方为4％膨润土＋0．4％K—HPAN＋0．6％SMC＋0．4％HS-1＋0．3％CHM＋0．3％NW-1＋2％SMP＋2％PSC＋4％SPNH。30余口井的现场试验结果表明，井下复杂和事故大幅度降低，钻井周期明显缩短，与使用前相比，复杂损失率由4．50％降为1．62％，平均机械钻速提高了26．88％，钻井周期缩短40．54％，且钻井液性能易于雏护，操作简单，满足安全快速钻井的要求。图8表5参3。

The law of stratigraphic physical and chemical properties of clay minerals distribution in Qingxi block was obtained by X-ray diffraction experiments,cuttings recovery rate and expansion ratio experiments,and the stratum clay mineral profile was built.Experiment results indicated that stratum clay minerals distributed as M shape,which need a strong inhibitory and sealing drilling fluid.It provided scientific basis for drilling fluid performance and maintenance in different sections.Aimed at the lithologic characteristics and drilling fluid technical difficulties in Qingxi block,the screening of inhibiter,fluid loss agent and high temperature stabilizer was done.The best formula of cationic drilling fluid with the strongest inhibitory and the highest sealing capability was established: 4% bent,0.4% K-HPAN,0.6% SMC,0.4% HS-1,0.3% CHM,0.3% NW-1,2% SMP,2% PSC,4% SPNH.After the application in more than 30 wells on site,the complex accidents in down hole greatly reduced and drilling cycle obviously shortened.The complex loss rate decreased from 4.50% to 1.62%,average rate of penetration enhanced by 26.88% and drilling cycle shortened by 40.5%.This drilling fluid could be easily maintained and operated which met the requirement of safe and fast drilling.