To investigate the variation of production decline rate at different water cut stages during oilfield development

this study explored the relationship between decline rate

water cut rise rate

and water cut based on relative permeability curves. The relationship between decline rate and water cut under injection-production balance conditions was established

followed by computational analyses on a thick oil reservoir Z and a multi-layer oil reservoir S. The results showed that

under ideal injection-production balance conditions

the decline rate at a certain water cut stage was jointly influenced by liquid production rate and irreducible water saturation. The decline rate exhibited a parabolic trend with increasing water cut and was proportional to the liquid production rate. For a given reservoir under known conditions

the magnitude of the production decline rate was primarily determined by the liquid production rate and could be controlled by adjusting parameters such as well spacing density and the ratio of injection to production wells

which affected the liquid production rate. By establishing the relationship between decline rate and water cut

factors influencing production decline are clarified

providing a basis for strategies to mitigate production decline.