Abstract: As some oilfields in Bohai Sea enter the middle and late stages of development, the treatment and transformation of low-production and low-efficiency wells are becoming more and more urgent. Horizontal branch wells technology is an effective measure to achieve the treatment of low-yield and low-efficiency wells. However, in practical applications, they are faced with problems such as dense well net, serious anti-collision problems, easy sand production in reservoirs, and poor wellbore stability. In view of these problems, the wellbore collision problem was overcome by optimizing the drilling trajectory. The drilling safety was ensured by optimizing the wellbore structure and drilling fluid system. In terms of completion, the completion sand control mode was optimized. Based on the multi-physical field coupling finite element simulation results, the structure of the sand control string was optimized, the preset director was designed, and lowered into the lower part of the sidetracking point of the branch wellbore to realize full support of the wellbore. The productivity shows that the production of Well A has increased from 5 m³/d to 45.2 m³/d, and the production remained 40 m³/d half a year later, which has achieved stable production. This shows that through the optimization and precise control of drilling trajectory, and the full support of horizontal open hole section and filling sand control technology, the single well production can be improved, and the efficient management of low-yield and low-efficiency wells can be realized.