HL-FFQH环保型水基钻井液体系的构建及应用

针对目前环保型钻井液体系应用效果不理想、成本高等问题，采用前期合成的5种无毒、易降解、金属含量达标的处理剂，优化出一套HL-FFQH环保型钻井液体系，配方为:4%膨润土浆+0.3%包被剂HLBE-2+2%降滤失剂HLJ-1+3%固壁剂HLGB-3+1%封堵剂HLFD-1+2%润滑剂HLR-2+重晶石。室内评价结果表明，该环保型钻井液体系流变性良好；8 h泥页岩膨胀量仅为2.5 mm，具有很强的抑制性；用7%钻屑污染后流变性能稳定，滤失量变化小于0.4 mL，具有优良的抗钻屑污染能力；经150℃、16 h老化后的钻井液润滑系数及泥饼摩阻系数分别为0.10和0.08，润滑性良好；生物毒性、生物降解性及金属含量等均符合环保指标；废弃的钻井液颜色较浅，滤饼和滤液不影响动植物的生长和生存。HL-FFQH环保钻井液体系在华北油田的4口井中获得成功应用。现场应用表明，该钻井液体系性能稳定、抑制防塌性强；具有良好的储层保护和环境保护能力；机械钻速较邻井提高了85.5%，无井下复杂事故发生。HL-FFQH环保型钻井液体系从前期配方和后期废弃物均符合环境保护要求。 

Development and Application of the Environmentally Friendly HL-FFQH Water Base Drilling Fluid

A new environmentally friendly water base drilling fluid HL-FFQH has been developed to address the problems encountered in using conventional environmentally friendly drilling fluids, such as poor engineering performance and high cost. This new drilling fluid was formulated with previously developed five additives which are nontoxic, easy-to-degrade and have heavy metal contents that meet the standard. The formula of the drilling fluid is:4% bentonite +0.3%HLBE-2 (encapsulator) + 2% HLJ-1 (filter loss reducer) + 3% HLGB-3 (borehole wall strengthening agent) + 1% HLFD-1 (plugging agent) + 2% HLR-2 (lubricant) + barite. This drilling fluid showed good rheology in laboratory evaluation. Length of expansion of shale core in 8 h was only 2.5 mm, indicating that this fluid had good inhibitive capacity. After contaminated with drilled cuttings, the change of the filter loss of the drilling fluid was less than 0.4 mL, indicating that the drilling fluid was resistant to cuttings contamination. After aging at 150℃ for 16 h, the drilling fluid had friction coefficient and mud cake friction coefficient of 0.10 and 0.08, respectively, proving that this drilling fluid had good lubricity. Biotoxicity, biodegradability and content of heavy metals all met the relevant standards. The waste drilling fluid was light-colored, and the mud cake and filtrates of the drilling fluid did not affect the growth and life of animals and plants. No damage to the reservoir and downhole troubles have been found using this drilling fluid. Compared with offset wells, the ROP was increased by 85.5%. The HLFFQH drilling fluid conforms to the requirements of environmental protection from formulating to waste fluid treatment.