适用于柴油基钻井液的洗油型冲洗液研究

针对柴油基钻井液易残留井壁和套管壁表面，影响水泥环胶结质量这一问题，进行了FYJ洗油型冲洗液研究：（1）建立表面活性剂的优选方法；（2）优选高效表面活性剂；（3）以清洗效率、润湿反转性能及其与柴油基钻井液和水泥浆的相容性为评价指标，获得综合性能良好的FYJ洗油型冲洗液。实验结果表明：（1）适用于洗油型冲洗液用表面活性剂应选用HLB值在12~15的阴离子型、非离子型或两者复配的表面活性剂体系，且加入表面活性剂的溶液表面张力（γ）接近或小于钻井液的临界表面张力（γ_c≈23~27 mN/m），而较优加量至少大于临界胶束浓度（CMC值）；（2）FYJ洗油型冲洗液对不同种类的柴油基钻井液的清洗效率皆达到82%以上，有较好的抗温抗盐性；（3）该洗油型冲洗液与柴油基钻井液和水泥浆的相容性良好。

Flushing Fluid for Diesel-based Drilling Fluid Cleaning

A diesel-based drilling fluid (DBDF) is wildly applied in complex deep wells. However, its strong adhesion to the casing and the well would severely affect the cementing quality. To solve this problem, a study on the preflush system FYJ was conducted: (1) established an optimized method of a surfactant; (2) optimized the efficient surfactants; (3) evaluated indexes referring to the fluid flushing efficiency, the properties of wetting reverse, and compatibility with drilling mud, and we obtained a flushing fluid FYJ having a good comprehensive property. The results showed that (1) Anionic/non-ionic or mixed surfactants with HLB values of 12-15 should be used in preflush systems, the minimum surface tension of the surfactant solution ((γ_min) should be close to or less than that of soaking surfaces of DBDF (γ_c≈23-27 mN/m), and the optimum addition amount of the surfactant should be greater than the critical micelle concentration (CMC value). (2) The preflush system FYJ can remove 82% of the DBDF attached to the well and casing walls, which have a strong temperature and salt resistance. (3) The preflush system FYJ provides good compatibility with DBDF and slurry, and it can effectively dilute the DBDF and slurry.