Study on inter-segment interference mechanisms and patterns between horizontal well sections in a combined well pattern of horizontal and vertical wells in offshore oilfields

Abstract

Abstract In the development of heavy oil fields in the Bohai Sea, the “horizontal + directional” well pattern has significantly improved recovery rates. However, as the oilfield enters the ultra-high water cut stage, changes in waterflooding behavior and production characteristics lead to a more complex distribution of remaining oil, posing challenges for subsequent development. This study introduces a dynamic interference analysis method that integrates three-dimensional (3D) physical modeling with numerical simulation. The method optimizes the interference prediction model under the “horizontal + directional” well pattern, aiding in well placement optimization and enhancing development efficiency during the ultra-high water cut period. Additionally, a phenomenon was observed where remaining oil concentrates in the central segment during the displacement process. Through numerical simulations under varying permeability rhythms, the impact of the injection-production relationship on the distribution of remaining oil was revealed, providing a theoretical foundation for well pattern optimization. The findings offer technical support for the continued development of Bohai Oilfields under ultra-high water cut conditions and provide valuable guidance for other offshore heavy oil fields. The new methods proposed in this study can improve recovery rates in complex waterflood environments.