Highest Wellbore Stability Obstacle Avoidance Drilling Trajectory Optimization in Complex Multiple Strata Geological Environment

Drilling trajectory optimization (DTO) is an important step in intelligent control of directional drilling process. DTO in complex multiple strata geological environment is a new nonlinear, strongly constrained, black-box multi-objective optimization problem with discrete objectives. In this paper, a multi-objective evolutionary algorithm (MOEA) optimization framework is present for an obstacle avoidance drilling trajectory design model. First, a new three-segment trajectory model is established by natural curve method to measure the whole trajectory positions. Meanwhile, a drilling point wellbore stability model is derived by Mohr-Coulomb failure criteria. Based on this calculation model, the trajectory data is mapping to get a multi-strata parameter field. Several representative MOEAs are adopted to design the highest wellbore stability trajectory in this multi-strata geological environment. A case study from actual drilling site shows that the result of adaptive non-dominated sorting genetic algorithm (ANSGAIII) is better than that of traditional trail and error drilling trajectory design, which has a good application prospect in drilling engineering.