成膜防塌钻井液技术研究与应用

川西海相雷口坡组地层地质条件复杂，主要表现为裂缝发育、裂缝走向杂乱、地层破碎。为解决前期钻井中出现的井壁失稳、掉块卡钻、电测遇阻等复杂情况，通过对雷口坡组地层井壁失稳分析，引入成膜封堵技术，开展钻井液性能评价，形成一套适宜川西海相超深井抗高温成膜防塌钻井液体系，具有良好的流变性、抗高温稳定性及较强的抗污染能力，且在减少压力传递、提高裂缝封堵能力方面展现出优良的性能。现场应用表明，采用该套钻井液进行钻进、取心、电测、完井作业顺利；同比前期施工井，平均机械钻速提高39.9％，平均钻井周期缩短22.6％，平均纯钻率提高11.6％，未出现邻井发生的井壁失稳等复杂现象，对加快川西海相超深井勘探开发进程具有重要意义。

Research and Application of Film-forming Anti-collapse Drilling Fluid System

The geological conditions of the marine Leikoupo Formation in Western Sichuan are complex, which are mainly manifested as fracture development, fracture strike disorder, formation fragmentation, etc. In order to solve the problems such as wellbore instability, block sticking, and resistance of electric logging, etc. , the technical countermeasures of ultra deep well drilling fluid anti sloughing are proposed by analyzing the engineering geological characteristics of Leikoupo Formation, and the anti collapse drilling fluid system of marine facies in Western Sichuan is constructed. According to the laboratory evaluation, the drilling fluid of this system has strong ability of temperature resistance, pollution resistance and plugging inhibition. The field application shows that drilling, coring, electrical logging and completion operations are smooth. Compared with the previous construction wells, the average ROP is increased by 39. 9% , the average drilling cycle is shortened by 22. 6% , and the average pure drilling rate is increased by 11 . 6% . There is no complex phenomenon such as wellbore instability in adjacent wells, which is of great significance to accelerate the exploration and development process of marine ultra deep wells in Western Sichuan.