Multi-objective optimization design of deviation-correction trajectory considering the production loss in shale gas cluster well

Abstract

In shale gas mining, the inter-fracture interference effect will significantly occur if the actual well deviates from the planned trajectory. To reduce production loss, operators want to get back on the planned trajectory economically and safely. Based on this, a multi-objective optimization model of deviation-correction trajectory is established considering the production loss evaluation. Firstly, the functional relationship between the production envelope and the fracturing depth is constructed, and the production loss is obtained by combining the calculation method of volume flow. Based on the proposed “double-arc” trajectory design method, the production loss of the fracture on the deviation-correction trajectory is obtained. Finally, combined with the well profile energy evaluation, a new optimization model of deviation-correction trajectory is established. The results demonstrate that after optimizing the fracturing depth, the production loss of the deviation-correction trajectory is reduced by 13.2%. The maximum curvature value results in a trajectory with a minimum production loss yet a maximum well profile energy. The proposed model reduces the well profile energy by 15.6% compared with the existing model. It is proved that the proposed model can reduce the probability of drilling accidents and achieve high gas production in the later mining stage. This study fully considers various factors affecting horizontal wells in the fracturing area, which can provide theoretical guidance for the design of deviation-correction trajectory.