多元协同防塌钻井液技术在临盘油田探井的应用

Application of multivariate synergistic anti-caving drilling fluid technology in exploratory wells of Linpan Oilfield

李钟 罗石琼 罗恒荣 王佩平 郭爱林 宋光明

中国石化西南石油工程有限公司临盘钻井分公司，山东 德州 251500

Linpan Drilling Company, Southwest Oilfield Service Corporation, SINOPEC, Dezhou 251500, China

针对临盘油田探井钻井过程中常因沙河街组泥页岩井壁失稳而导致井下故障频发这一难题，通过X衍射、理化性能及扫描电镜等实验方法对井壁失稳机理进行了分析，并依据“多元协同”稳定井壁理论研发了一套“多元协同”防塌钻井液技术。室内评价结果表明：该钻井液的API滤失量小于2.6 mL，HTHP滤失量小于10.0 mL，动塑比0.5左右，抗温150 ℃，岩屑回收率95.0%以上，膨胀率5.0%以下。“多元协同”防塌钻井液技术已在临盘油田16口中深探井进行了现场应用，均未发生由于井壁失稳而造成的井下故障。沙河街组平均井径扩大率小于10%，完钻电测一次成功率达93.75%，平均机械钻速由11.23 m/h提升至20.07 m/h，累计节约周期130.75 d，说明该“多元协同”防塌钻井液技术能有效解决临盘油田探井泥页岩井壁失稳难题，值得在该地区推广应用。

In order to solve the downhole troubles caused by wellbore instability in Shahejie Formation during drilling of exploratory wells in Linpan Oilfield, the wellbore instability mechanism in this area was analyzed using the experimental methods of X-ray diffraction, physical-chemical properties and scanning electron microscope. A multivariate synergistic anti-caving drilling fluid was developed based on the theory of multivariate synergy wellbore stabilization. The laboratory test shows that this drilling fluid has good property, with API filter loss of less than 2.6 mL, HTHP filter loss of less than 10.0 mL, the ratio of yield value to plastic viscosity at around 0.5, temperature resistance of above 150 ℃, the cuttings recovery rate over 95.0%, and expansion rate less than 5.0%. The multivariate synergistic anti-caving drilling fluid technology has been used in 16 middle-deep exploratory wells in Linpan Oilfield, no downhole troubles caused by wellbore instability occurred. The average hole diameter enlargement ratio in Shahejie Formation was kept under 10%, the one-time success rate of electric logging increased to 93.75%, the penetration rate increased from 11.23 m/h to 20.07 m/h, and the well construction period was shortened totally by 130.75 days. Thus it could be seen that this multivariate synergistic anti-caving drilling fluid technology could solve effectively the downhole troubles during drilling of exploratory wells and should be popularized and applied in Linpan Oilfield.

10.6056/dkyqt201901022