渤海油田大位移井下套管设计难点及对策研究

Casing running design difficulties and solutions for extended reach wells in Bohai Oilfield

摘要:

渤海油田大位移井套管下入困难的问题亟待解决。本文以渤海油田一口大位移水平井A井为例，从设计的角度分析了该井φ244.5 mm套管下放技术难点，并利用LANDMARK软件对影响套管下放的因素进行了分析，结果表明，轨道造斜点的提高、表层套管下深的增加、超大稳斜角条件下套管磅级的减轻、摩阻系数的降低、漂浮段长的增加均能减小套管下放的摩擦力，提高套管下放悬重。通过逐一优选A井轨道造斜点、表层套管下深、套管磅级、摩阻系数、漂浮段长，最终设计A井φ244.5 mm套管采用漂浮法下入，漂浮段长1200 m，预测套管下放到位的悬重与实测值的相对误差为6.34%，在工程误差允许范围内。制定了渤海油田大位移井下套管设计流程，设计过程中，应综合考虑轨道造斜点、表层套管下深、套管磅级、摩阻系数、漂浮段长对套管下放悬重的影响，优选最优方案，确保套管顺利下放。

关键词:大位移井;套管下放;漂浮下套管;设计优化;设计流程;渤海油田

Abstract:

The difficulty in casing running needs to be solved urgently for extended reach wells in Bohai Oilfield. Taking a well A in Bohai Oilfield as an example, this paper analyzes the technical difficulties in φ244.5mm casing running from the design point of view, and analyzes the factors affecting casing running using the software of LANDMARK. The results show that if the kick off point becomes shallow, the surface casing running depth becomes deeper, and the hold angle is over large, then less casing unit weight, reduction in the friction coefficient, and increase in the floating section will lead to reduction in casing running friction, and increase in the casing hanging weight. By optimizing the above parameters, the φ244.5mm casing running plan was designed with the floating manner with the length of the floating section as 1200m. The relative error between the predicted value and the measured value of the casing hanging weight was 6.34%, which was within the allowable engineering error range. The casing running design process has been developed for extended reach wells in Bohai Oilfield. In the casing running design, the kick off point, the surface casing running depth, the case weight, the friction coefficient and the floating section should be considered comprehensively to optimize the running plan to ensure successful casing running.

Key words:extended reach wells; casing running; floating casing; design optimization; design process; Bohai Oilfield