新型抑制性水基钻井液技术及性能评价

New water-based drilling fluids suppression technology and performance evaluation

针对该地区页岩地层水平井段容易产生水化膨胀缩径和造浆能力强的技术难题,利用新型无机盐和聚合醇等处理剂,开发一种新型水基钻井液,并模拟焦石坝地区下志留统龙马溪组地层温度(约80℃),开展老化实验评价;实验表明:该钻井液体系具有抑制性强,滤失量小的特点。此外,利用聚磺钻井液滤液、聚合钻井液滤液、清水和所研制的水基钻井液的滤液浸泡页岩岩心,评价常温常压膨胀量。由于聚合醇胶体填充页岩的细小孔隙或微裂缝,阻挡滤液进入泥页岩地层;另一方面,无机盐中水化能力弱的K^+将晶层间隙中水化半径较大和水化能力强的Ca^+、Na^+等离子交换出来,并与页岩晶层牢固结合,阻止晶层间距增大,抑制页岩水化膨胀;对页岩开展滚动回收率实验测试,页岩在所研制的水基钻井液中的回收率达到99.7%,体现出较强的抑制性能。

For the technical problems of shale formations horizontal section proning to hydration expansion necking and strong pulping in jiao shi ba area, developmented a new water-based drilling fluids using new inorganic and polymeric alcohol treatment agent and conducted evaluation simulation Longmaxi Silurian formation temperature （about 80℃ ）. The results showed that： drilling fluid system has the characteristics of strong inhibition and a small amount of fluid loss. Moreover, evaluated shale expansion amount in normal temperature and pressure using polysulfonate mud filtrate, polymerization mud filtrate, water and the development of water-based drilling fluid fil- trate soaked shale cores. Since the polymeric alcohol colloid filling small voids or mierocracks shale barrier filtrate into shale formations; On the other hand, weak hydration K^＋ inorganic salts exchange out larger radius and hydration hydration ability of Ca^＋, Na^＋ ion from the crystal layer gap and combined with a solid shale crystal layer.pre- vents crystal layer spacing increasing, inhibition of shale hydration expansion. Scroll to carry out the recovery of shale experimental test, developed shale in water-based drilling fluid recovery rate of 99.7%, reflecting the strong rejection.