Hydraulic-Fracture-Treatment Design Simulation

Abstract

Hydraulic fracturing is a technique for simulating wells completed in low-permeability reservoirs. The process involves the pressurization of an isolated perforated section of the wellbore with a viscous fluid until the induced stresses exceed the formation strength, which causes a failure and thus creates the fracture. Proppants are then pumped into the newly created fracture with viscous fracturing fluid as a carrier. Once initiated, the fracture propagates as additional fracturing fluid is injected. Following the release of the fracturing pressure, the proppants hold the fracture open and provide a conductive channel through which the reservoir fluids flow to the wellbore. Only vertical fractures are considered here. Hydraulic-fracturing simulators are used to design the treatment volume, proppant size and type, and pumping schedules to obtain the desired fracture geometry and conductivities. The pumping schedules are designed by running these simulators on a trial-and-error basis until a desired propped geometry is obtained that will ensure maximum proppant coverage at the end of pumping. With these propped fracture geometry and conductivity data, an economic estimate is usually made for the treatment for a given fracture length and an optimal design is selected for the maximum return of the well.