鲁迈拉定向井钻井设计优化与应用

Optimization and Application of the Directional Well Drilling Procedure Design in Rumaila Oilfield

摘要:

为了降低定向井摩阻扭矩，提高钻井速度，针对地质特点和钻井难点，建立了井眼轨道和岩石可钻性回归计算模型。通过五段制轨道剖面的优化，最优井眼曲率为（2.85°～3°）/30 m、最大井斜角为30°；技术套管下至Sadi层8～15 m，确保了S型定向井安全钻进，裸眼内摩阻系数由0.52降至0.35，套管内摩阻系数由0.35降至0.28；Rus软硬夹层优选试验KM533复合钻头，解决了常规PDC钻头磨损快、牙轮钻头机械钻速低的问题。通过上述3项技术的研究与应用，鲁迈拉S型定向井实际顶驱扭矩降低30%以上，钻头使用数量降低2.7只，钻井周期缩短18.58 d。

Abstract:

In order to reduce the drag and torque in directional well drilling and increase the ROP, according to the geological conditions and drilling difficulties, a regression calculation model of borehole trajectory and rock drillability was established. By the optimization of 5-section trajectory sections, the optimal hole curvature 2.85°～3°/30m and maximum well angle 30°were determined, the intermediate casing was put down to sadi layer 8～15m to ensure the completion of S-shaped directional well. As the result, the friction coefficient in the open hole is reduced from 0.52 to 0.35 and casing internal friction coefficient from 0.35 to 0.28. The quick wearing of conventional PDC bit and low ROP of cone bit are solved by optimization test on KM533 composite bit in RUS soft and hard interlayer. Based on the technical research and application, the actual top driven torque of Rumaila S-shaped directional well is lowered by more than 30%, the mumber of used bits is reduced by 2.7 and the drilling period is decreased by 18.58d.