Simulation of blocking of hydraulic fracture near injector in a reservoir simulator

Abstract

Mature fields, as a rule, are developed using flooding technology. During long-term operation of field, in order to maintain the fluid flow rate at the same level, it is necessary to increase the bottom-hole pressure of the injector, which, when the pressure of the fracturing is exceeded, leads to the formation of fractures near the injectors. Uncontrolled growth of these fractures can lead to a breakthrough of water through it into the drainage zone of the producer and increase in the water cut of the production. This phenomenon has been observed in several fields, so the task of blocking of hydraulic fractures near injector is relevant. The existing mathematical models of blocking of hydraulic fractures near the injectors do not allow to determine the volume of leaks from the fracture in order to accurately calculate the volume of the injected reagent. The article describes the creation of a physical and mathematical model of injection of a polymer solution in water in the fracture. The aim of the work is to establish the dependencies of the critical fracture filling time and the volume of polymer leaks on the flow rate of the injected reagent. The mathematical model developed in the article is based on the laws of conservation of mass, momentum and energy for the oil, water and polymer. A reservoir simulator model describing the process of colmatation of hydraulic fracture near injector is created. The distribution of the concentration of the retained polymer was obtained both in the fracture and outside it. The critical time of filling the fracture was determined for the specified rock properties and technological parameters of the well operation. It is determined that the volume of polymer leaks becomes larger due to an increase in the flow rate of the injected displacement agent.