埕海XX大位移水平井244.5 mm套管全漂浮下入研究与分析

Full-floating 244.5 mm casing running at Chenghai XX extended reach horizontal well

大港油田埕海XX井完钻井深3850 m,水平位移3098 m,其中244.5 mm技术套管采用全漂浮工艺下深至3485 m,中完水垂比达2.58,创造中石油244.5 mm套管漂浮下套管漂浮段长度纪录。该井311.1 mm井眼下244.5 mm套管,高水垂比的井身结构决定了较大的井筒摩阻,进而导致套管下入悬重不足、易遇阻、易黏卡等难题的发生。结合全漂浮下套管原理、下入工艺与工程配套、现场实施与应用效果评价开展了套管下入研究与分析。分析结果推荐该井身结构的大位移水平井采用全漂浮下套管工艺进行套管下入,采用全漂浮工艺不仅可以使套管悬重下入至预定深度,下入过程中大幅减少侧向压力,显著地减小下套管黏卡风险,且施工安全性大为提高。

The Chenghai XX well drilling depth is 3850 m and horizontal displacement is 3098 m.The full-floating 244.5 mm intermediate casing running reaches a depth of 3485 m with a water vertical ratio of 2.58,setting a record for the longest floating segment of 244.5 mm casing among CNPC wells.The running of a 244.5 mm casing in a 311.1 mm wellbore,combined with the high water vertical ratio of the casing program,resulted in significant friction resistance,leading to difficulties during casing running such as insufficient hook load,resistance,and sticking.Research and analysis were conducted on casing running by combining the principles of full-floating casing running,casing running techniques,and engineering support,as well as effect evaluation of on-site implementation and application.It was recommended in the result that,for extended reach horizontal wells with this kind of casing program,full-floating casing running should be ideal.With the above method,casing running can reach the designed depth with sufficient hook-load,significantly reducing lateral pressure during installation and the risk of casing sticking.Therefore,construction safety can be significantly improved.