关键词: 大位移井, 定量评价方法, 轨迹优化, 评价指标, 权重

Abstract: At present，extended-reach well（ERW）drilling has become an important means for oil and gas exploration and development，and trajectory design optimization is the key to the successful drilling of ERW and the improvement of operating efficiency. With the continuous increase in horizontal displacement and horizontal length to vertical depth ratio，ERW drilling is facing many serious challenges. Therefore，it is necessary to comprehensively analyze and evaluate the factors affecting trajectory design，such as trajectory control ability and wellbore stability，so as to form an integrated technical thinking. In this study，a matrix of trajectory evaluation indicators was first established by analyzing the characteristics of ERW drilling technique，and then scores and weights of all indicators were determined based on expert experience. Consequently，quantitative evaluation was used to judge the selection of ERW trajectory，and applied to the ERW design in an oilfield. Drilling operations were carried out in the field strictly following the selected trajectory plan，and finally a high-quality trajectory was achieved for the whole well. The results show that the evaluation method is practicable and feasible，and provides a technical basis and guiding method for selecting the design plan of ERW trajectory.

Key words: extended-reach well（ERW）；quantitative evaluation method, trajectory optimization, evaluation indicators, weight