Abstract
A reasonable wellbore trajectory is crucial for achieving geological goals and ensuring safe and efficient on-site operations. Currently, the selection of wellbore trajectories is mainly evaluated based on operational feasibility and target safety. However, the trajectory plan that is easy to construct and smoothly hits the target May have potential disadvantages such as high drilling costs, poor stress state of the drill string, difficulty in meeting wellbore cleaning requirements, and long drilling cycles. The current trajectory optimization methods have not taken these factors into account, which cannot comprehensively and scientifically select wellbore trajectories, limiting the effective assessment of wellbore trajectories based on past oilfield experience. This Article considers key indicators such as trajectory difficulty, drill string stress, wellbore cleanliness, drilling cycle, and drilling cost, innovatively establishes the concept of trajectory difficulty coefficient, optimizes trajectory selection evaluation indicators and scientifically quantifies them, establishes a trajectory optimization quantification method, and provides theoretical basis for oilfield trajectory selection and Wellhead layout scheme selection. Taking A oilfield as an example, using the trajectory optimization scheme proposed in this Article, schemes 4 is chosen to be the optimal trajectory, with minimum trajectory difficulty coefficient, good stress state of the drill string and wellbore cleaning, the shortest footage resulting in the least drilling cost. In addition, the directional well scheme has core advantages over the vertical well scheme, such as shorter well site construction costs and overall drilling cycle. The comprehensive selection method for wellbore trajectory established in this Article provides theoretical support for trajectory selection.