The design of a trajectory is significant to the efficiency and safety of a drilling process. In this paper, wellbore stability, indicated by the safe mud weight, is introduced as constraints to formulate a drilling trajectory optimisation problem. The upper and lower bounds of the safe mud weight are analysed according to the real data of a well. To solve the optimisation problem with strict constraints, we devise a new multi-objective optimisation algorithm. The devised algorithm takes advantage of inverted generational distance and knee points, and improves the convergence and diversity of the obtained solutions by modifying the selection process. Simulation results show that the devised algorithm is effective on the drilling trajectory optimisation problem constrained to wellbore stability.

轨迹的设计对于钻井过程的效率和安全性具有重要意义。在本文中，以安全泥浆重量表示的井眼稳定性被引入作为约束来制定钻井轨迹优化问题。安全泥浆重量的上下限根据一口井的实际数据进行分析。为了解决具有严格约束的优化问题，我们设计了一种新的多目标优化算法。所设计的算法利用逆代距离和拐点，并通过修改选择过程来提高所获得解的收敛性和多样性。仿真结果表明，所设计的算法对约束井筒稳定性的钻井轨迹优化问题是有效的。