Numerical Simulation Study Of Recfracturing Based On Finite Element Method

The development of low permeability reservoir mainly by hydraulic fracturing. In the production process of oil and gas wells, the reservoir or fracturing technology may lead to hydraulic fracture failure, resulting in the decline of production. In order to give full play to the reservoir potential and ensure stable production, refracturing must be done on these oil and gas wells, reservoir full potential, ensure oil and gas wells stable production.Finite Element Method can precise simulate complex boundary and the grid division is flexible. Successfully implemented the numerical simulation study of refracturing. In this paper, the finite element method was used to treat oil-water two-phase seepage flow problem. Established oil-water two-phase flow finite element equations and solved them. Using Line unit simulation crack model, mesh generation using arbitrary triangular units. Realized with repeated fracturing reconstruction of fracture failure, timing, method of reservoir numerical simulation research.In this paper, the numerical simulation of hydraulic fracturing and refracturing of vertical well and horizontal wells is conducted. Studied the effect of fracture permeability changes on well productivity, the process of the crack closure is simulated by the exponential decrease of fracture permeability. Studied the influence of refracturing time on vertical/horizontal well development effect. Studied the influence of fracture conductivity on vertical/horizontal well development effect. Through comparative analysis of simulation results, shows that the failure of the fracture has a greater impact on the oil well productivity, the optimal timing of vertical and horizontal refracturing is the sixth year, and the optimal way of refracturing for vertical well and horizontal well is Lengthen the old fractures. We draw meaningful conclusions, and provide a theoretical guidance for the on-site fracturing operation.