AT40井区盐上承压堵漏及穿盐钻井液254技术应用

Pressure sealing on salt layer and technology of drilling fluid through salt layer in well AT40 area

杨军义 王健

Yang Junyi Wang Jian

中国石化 西北油田分公司 工程监督中心, 新疆轮台 841600

Engineering Supervision Center, SINOPEC Northwest Company, Luntai, Xinjiang 841600, China

AT40井区三开钻遇"盐膏层",为平衡"盐膏层"地层蠕变,钻井液密度高达1.65~1.70 g/cm3,为避免同一开次的白垩系、侏罗系、三叠系、石炭系等低地层压力地层压漏、压差卡钻风险,需对低地层压力地层做承压堵漏.该开次裸眼段长,地层岩性多变复杂,承压堵漏存在难点.另外,"盐膏层"钻进期间,控制"盐膏层"蠕变速率满足下套管要求,高密度、欠饱和盐水聚磺体系良好的流变性能、防塌性能也是"盐膏层"钻进期间钻井液技术重难点.针对该井区三开复杂情况,采取随钻封堵、分段承压、合理的钻井液密度选择、优化钻井液流变性等系列措施,成功解决该井区盐上承压堵漏及穿盐技术难点.

In the third opening of the well AT40 area, "salt gypsum layer" was encountered. For the balance of "salt gypsum layer" formation creep, the density of drilling fluid was up to 1.65-1.70 g/cm3. In order to avoid pressure leakage and differential pressure sticking risk in the low-pressure formations such as Cretaceous, Jurassic, Triassic and Carboniferous during the same opening, pressure plugging was demanded. Due to long opening hole and complex formation lithology, problems existed for pressure sealing. Besides, while drilling in the "salt gypsum layer", controlling the creep rate of "salt gypsum layer" to satisfy the requirement of casing, and the good rheological properties and anti-collapse performances of high-density and under-saturated saltwater polysulfonate system were the difficult points of drilling fluid technology. Aiming at the complicated situation in this area, taking the measures of plugging while drilling, sectional bearing, reasonable selection of drilling fluid density, optimizing drilling fluid rheology, we solved the difficulties of pressure sealing on the salt layer and the technology of drilling fluid through salt layer in the well AT40 area.

https://doi.org/10.11781/sysydz2014S1127