曹妃甸油田浅层大位移井管柱作业极限分析与优化设计

在浅层大位移钻井中,井下管柱上产生高摩阻扭矩,管柱作业极限问题突出,急需开展大位移井管柱作业极限分析与优化设计的研究。基于管柱平衡微分方程,综合考虑接触力、摩阻力、管柱内外钻井液等因素影响,建立管柱摩阻扭矩计算模型;以井眼延伸长度为目标,考虑地面和井下各种约束因素的影响,建立管柱作业极限的预测模型。针对曹妃甸油田一口浅层大位移井,计算不同工况下管柱摩阻扭矩,预测管柱作业极限,并提出优化设计方案。结果表明,采用滑动钻进技术无法达到设计井深,采用旋转钻进技术可达到设计井深,但存在一定的风险。提升钻机性能后,采用旋转钻进技术可安全达到设计井深;优化井身结构后,采用滑动钻进技术并辅以减摩措施可达到设计井深。

Analysis and Optimization Design of Tubular Operating Limit in Shallow Extended-Reach Drilling of Cao Feidian Oil Field

In shallow extended reach drilling, high friction torque is generated on downhole tubular string, and the operating limit problem about tubular string is prominent. Therefore, it is urgent to carry out the research on the operating limit analysis and optimization design of tubular string in extended reach drilling. Based on the equilibrium differential equation of drill string and considering the influence of contact force friction and drilling fluid inside and outside the drill string, the calculation model of friction torque of tubing is established in this paper; Taking the borehole extension length as the target and considering the various kinds of constraints on the surface and downhole, a prediction model at operating limit of tubular string is established. Aiming at a shallow extended reach drilling in Cao feidian Oilfield, the friction torque of tubular string under different working conditions is calculated, the operation limit of tubular string is predicted, and the optimal design scheme is put forward. The results show that the sliding drilling technology can not reach the design well depth, and the designed well depth can be achieved by rotary drilling technology, but there are some risks. The design well depth can be safely reached by using rotating drilling technology after improving the performance of the drilling rig; The depth of the designed well can be reached by using sliding drilling technology and antifriction measures after optimizing the wellbore structure.