涠洲K油田复杂工况旋转尾管固井技术

南海西部的北部湾盆地涠洲K油田X1井是一口工况较为复杂的定向井，存在井斜大、裸眼段长、高温、储层压力衰竭带来的异常低压，同时具有较高的气油比等因素共同作用，给固井作业带来极大的挑战。由于φ177.8 mm尾管与φ215.9 mm井眼环空间隙较小，如果采用常规静态尾管固井技术固井顶替效率偏低，将会导致井下漏失和无法压稳地层，引起气窜，造成压力衰竭和高温目的层位的固井质量难以满足后期射孔开采的要求。为了保证复杂工况下油气水层间良好封隔，该井选择使用旋转尾管下入固井技术和抗高温早强防气窜水泥浆体系，同时优选新型油基钻井液冲洗液和隔离液，有效清洁滤饼，并且实现胶结面的润湿反转；使用软件对尾管旋转扭矩进行精确模拟和提高尾管下入居中度，完成了压力衰竭和高温目的层φ177.8 mm尾管固井作业。采用高清扇区水泥胶结测井仪器进行SBT扇区水泥胶结测井结果表明:油气水层实现了良好的层间封隔，全井段固井质量优，较邻近区块的K2井有了明显的改善，满足了后续射孔开采的要求。 

Rotary-liner Cementing Technology for Use in Complex Working Conditions in the Weizhou K Oilfield

The well X1 drilled in the Weizhou K Oilfield, Beibu Gulf Basin, western South China Sea, is a directional well with complex downhole conditions. The problems associated with this well include high well angle, long open section, high temperature, abnormal low pressure resulted from depletion of reservoir pressure, and high gas/oil ratios, which as a whole present a challenge to well cementing operations. When cementing the φ177.8 mm liners in φ215.9 mm wellbore, low displacing efficiency will result if conventional static liner cementing technology is used because of the narrow clearance between the line string and the wellbore. Problems associated with this operation include lost circulation, gas channeling because of poorly cemented formations, formation pressure depletion, and poor cementing quality of the high temperature reservoirs that cannot satisfy the needs of subsequent production through perforation. To ensure good separation between oil, gas and water zones under complex work conditions, a rotary-liner cementing technology and a high temperature early-strength anti-channeling cement slurry have been used in the cementing the well X1. New flushing fluid and spacer for the oil base mud used were selected for better cleaning mud cakes, and for reversed wettability of the surfaces of the cement sheath and the borehole wall. Using computer software, the rotary torque of the liner string was accurately simulated, and the eccentricity of the liner string improved. The φ177.8 mm liner, which penetrated a pressure-depletion and high temperature reservoir, was successfully cemented. Sector cement bond tool logging data showed that good separation between oil, gas and water has been obtained. Cement quality of the whole well was excellent, better than the cementing quality of the well K2 drilled nearby, satisfying the needs of subsequent production through perforation.