龙马溪页岩井壁失稳机理及高性能水基钻井液技术  

Research on Mechanisms of Wellbore Instability of Longmaxi Shale Formation and High Performance Water Base Drilling Fluid Technology

作　　者：唐文泉[1,2,3] 高书阳[2,3] 王成彪[1] 甄剑武[2,3] 陈晓飞[2,3] 柴龙[2,3] 

机构地区：[1]中国地质大学(北京),北京100083 [2]中国石化石油工程技术研究院,北京100101 [3]页岩油气富集机理与有效开发国家重点实验室,北京100101

出　　处：《钻井液与完井液》2017年第3期21-26,共6页Drilling Fluid & Completion Fluid

基　　金：国家重大专项"彭水地区常压页岩气勘探开发示范工程"(2016ZX05061);国家自然科学基金重大项目"页岩油气高效开发基础理论研究"(51490650);"川西低渗气藏低伤害钻井液技术研究"(2016ZX05021004-002)联合资助

摘　　要：目前长水平井段井壁失稳问题仍是制约国内外页岩气资源钻探开发的重大工程技术难题。为解决龙马溪组页岩长水平井段的井壁失稳问题,采用X射线衍射分析、氦气孔隙体积测试、高压压汞测试、高分辨率场发射扫描电镜、CT扫描、岩石连续刻划强度等实验,分析了龙马溪组页岩微观组构特征及理化特性,探讨了微观组构特征、理化特性对龙马溪组页岩井壁稳定的影响。研究表明:龙马溪页岩富含脆性矿物,黏土矿物以伊蒙混层为主,微纳米孔隙发育,微裂隙呈缝状、近平行分布,敏感性矿物的存在及其层理、微裂缝发育是导致页岩井壁失稳的主要内在因素。为此,针对性地提出了多元协同稳定井壁水基钻井液防塌技术对策,即"强化封堵-适度抑制-合理密度-高效润滑"。应用该技术对策构建了高性能水基钻井液优化配方,评价表明,该体系有较好的封堵性和抑制裂缝扩展的能力。该体系在黄金坝区块2口井三开进行了现场试验。现场试验结果表明,该体系较好地解决了页岩长水平井段的井壁失稳和水平段摩阻较大的问题,为中国采用水基钻井液技术高效钻探开发页岩气资源提供了新的思路及经验。Presently the problem of wellbore instability in long horizontal wells is still a major technical problem in hindering the development of shale gas resources in the world. To solve this problem encountered in the long horizontal well section penetrating the shaly Longmaxi Formation, XRD analysis, pore volume tests by helium adsorption, high pressure mercury test, high resolution feld emission SEM, CT scanning and continuous rock engraving strength experiments were used to analyse the micro petro-fabric and physicochemical characteristics of the Longmaxi shale, and their effects on borehole stabilization. The studies showed that the Longmaxi shale was rich in brittle minerals, and the clay minerals were mainly I/S mixed layers. Pores of micro- and nano-meters in sizes were developed, and micro cracks in the formation were slit shaped and in nearly parallel distribution. The presence of water sensitive minerals and the beddings developed therein as well as the micro fractures were the main factors causing shale wellbore instability. A set of wellbore stabilization measures was presented to solve these problems using inhibitive water base drilling fuid with synergistic effect, that is, borehole wall plugging strengthening - controlled inhibitive capacity of drilling fuid – reasonable density of drilling fuid - effcient lubrication of drilling fuid. A high-performance water base drilling fuid was formulated based on this technical strategy, exhibiting good plugging, and the ability to suppress crack propagation. This drilling fuid was used in drilling the 3rd interval of two wells in the Huangjinba block, successfully resolved the problems of wellbore instability and high friction in the long horizontal section of the Longmaxi shale, providing a new clue and experiences of using water base drilling fuid in the drilling and exploring shale gas resources.

关 键 词：页岩气 井壁失稳 微纳米尺度 孔隙结构 水基钻井液 

分 类 号：TE254.3[石油与天然气工程—油气井工程]