Research on numerical simulation of water breakthrough characteristics and influencing factors after oil reservoir plugging to determine the variation pattern of water cut in such reservoirs: a case study of Y oilfield

Abstract

This study focused on the water breakthrough issue that still occurred after water shutoff using gel plugging agents. Taking the heavy oil reservoir with edge-bottom water in the Y oilfield as an example, the study investigated the water cut variations after water shutoff and analyzed the types of water breakthrough characteristics in the wells of this reservoir. The CMG numerical simulation software was used to study the influence of geological parameters on the water cut variations after water shutoff. The research findings revealed that the water breakthrough characteristics in all the treated horizontal wells were classified into low water cut breakthrough, pulse-type breakthrough, step-type breakthrough, and high water cut breakthrough. Additionally, it was observed that horizontal wells in different geological conditions exhibited distinct water breakthrough characteristics under the same water shutoff process conditions. Through numerical simulation and statistical analysis of field data, the main factors influencing the variation of water cut after water shutoff were identified as reservoir permeability, oil saturation, interlayer position, water avoidance height, injection-production well distance, oil viscosity. The research findings allowed for the prediction of water breakthrough characteristics after water shutoff or the analysis of reservoir structure configuration based on known water breakthrough characteristics.