埕海油田大斜度井超短尾管固井技术

Ultra-Short Liner Cementing Technology for Highly Deviated Wells in the Chenghai Oilfield

  • 摘要: 埕海油田大斜度井技术套管下不到底而漏封水层,采用尾管补救固井时存在超短尾管串在大斜度井段悬重轻、丢手和判断丢手是否成功困难、水层活跃易窜流、尾管串居中度差及顶替效率低等问题,为此进行了大斜度井超短尾管固井技术研究。在封隔式尾管悬挂器下部增加牵制短节,增大尾管串悬重;使用膨胀防窜水泥浆体系,以防止地层水窜流;应用PVI软件模拟优化扶正器加装位置,提高尾管串居中度;优化固井浆柱结构及流变性能,以提高顶替效率。综合上述措施,形成了大斜度井超短尾管固井技术。该技术在埕海油田2口大斜度井进行了现场试验,试验中牵制短节反向牵引明显,尾管串丢手顺利,丢手判断明显,油水层封隔良好,后期开采获得了稳定高产油流。研究表明,大斜度井超短尾管固井技术可以解决埕海油田大斜度井超短尾管固井难题,也可为其他类似复杂情况的固井提供技术参考。

     

    Abstract: In the Chenghai Oilfield’s highly deviated wells, the intermediate casing cannot be run to the correct depth, so that the water layers cannot be isolated. During the remedial cementing with ultra-short liners, there are such problems in the highly deviated segments as low hang weight, difficulty in releasing and its identification, an active water layer susceptible to channeling, a poor centralization grade of the liner, and low displacement efficiency. For that reason, the ultra-short liner cementing technology for highly deviated wells was investigated. A hold-down sub installed under the parker-type liner hanger could increase the hang weight of the liner. The expanding cement slurry system was used to prevent the formation water from channeling. The centralizer position was optimized with PVI to raise the centralization grade of liner, and the structure and rheological properties of cementing slurry column were optimized to improve displacement efficiency. The ultra-short liner cementing technology for highly deviated wells was then developed. The technology was applied in two highly deviated wells in Chenghai Oilfield, with a high downward force of the hold-down sub, successful liner releasing and evident identification of it, and well isolated oil-water layers. In the later production rounds, stable and high oil flow was obtained. The research demonstrates that the ultra-short liner cementing technology for highly deviated wells solves the problem of ultra-short liner cementing for highly deviated wells in the Chenghai Oilfield, and also provides a technical reference for cementing in other similar complex situations.

     

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