采用蚁群算法优化设计径向水平井转向器轨迹

APPLICATION OF ANT COLONY ALGORITHMS FOR OPTIMIZATION DESIGN OF DIVERTER TRAJECTORY FOR RADIAL HORIZONTAL WELL

径向水平钻井技术主要包括油气层套管段铣技术、井下大直径扩孔技术、完井技术和水力喷射钻井技术,前三项技术已日趋完善,而喷射技术因为在水平井段较短,达不到预期的深度。为有效地降低转向器对钻柱的阻力,对转向器阻力进行了受力分析,并以钻柱通过转向器发生弯曲变形时,对转向器产生的轴向反作用力为目标函数,在满足转筒与垂直方向的夹角、转向器轨迹最小弯曲半径、矫直转筒对钻柱的矫直偏量等设计变量最佳的条件下,采用蚁群算法对径向水平井转向器轨迹进行了优化设计。仿真结果表明,转向器对钻柱的阻力达到最小,与原设计值相比,转向器阻力减小了46.98%。同遗传算法仿真结果比较,转向器阻力减小了3.17%,蚁群算法仿真结果比遗传算法仿真结果好,符合实际情况。

Radial horizontal drilling technology mainly includes reservoir casing section milling, large-diameter hole reaming, completion and hydraulic jet drilling. The previous 3 items have been applied on fields and proved to be mature enough; while the jet drilling can not reach the desired depth due to the relatively short distance along the horizontal section. In order to effectively reduce the resistance on the drill string caused by the diverter, load analysis has been done regarding the diverter resistance. And taking the axial reactive force exerted on the diverter by the drilling string when buckling through the diverter as the objective function, on condition the angle between the rotor and the vertical direction, the minimum curvature of diverter trajectory, and rectifying offset of the drill string have an optimum design, ant colony algorithm is applied to do the optimization design of diverter trajectory for radial horizontal wells. The simulation results show the resistance to the drill string by the diverter reaches the minimum and can be reduced by 46.98% compared with the original design. Compared with genetic algorithm, ant colony algorithm does better, conforming to the actual situations, and the resistance can be reduced by 3.17%.