Modelling Geomechanics Into Petroleum Reservoir Numerical Simulation: A Coupled Technique in a Water Injection Project

Abstract

Once a reservoir has been discovered it is essential to characterize it as accurately as possible in order to determine the most effective way of draining the recoverable oil. Reservoir characterization involves a great amount of data from geology, laboratory and production. An important data aspect in reservoir characterization is whether or not to consider geomechanic effects on the reservoir response. This is true in several exploitation scenarios and in particular when designing water injection projects for high-pressure/high-temperature reservoirs.This work describes the construction and numerical simulation of a reservoir model with incorporation of geomechanics for a real oilfield producing under waterflooding. Firstly, the model boundaries are prolonged to highlight the reservoir geomechanical behavior in the producing area. Secondly, the reservoir model is populated with geomechanical variables like vertical and horizontal stresses and equilibrated. Thirdly, a coupled procedure is implemented that allows the incorporation of geomechanics during numerical simulation of reservoir behavior. In this coupled procedure a commercial numerical flow simulator resolves the fluid flow behavior while a commercial geomechanical package controls the deformation aspects that occur during waterflooding.The technique developed in this work has been applied for reservoir performance forecasting of a giant Brazilian deepwater oilfield producing by water injection. Results obtained in this real case problem revealed important geomechanical features that must be considered in complex oil exploitation project scenarios in which limited information and production uncertainties are present.

Coupling of Stress Dependent Relative Permeability and Reservoir Simulation

“…The sequentially coupled approach was used in this paper to couple IMEX and FLAC3D to perform the coupled simulation, using procedures implemented by various researchers 6,10,12,22 . The approach simply allows IMEX and FLAC3D to exchange information in both directions, through a third party code.…”

“…The interaction of these parameters and the dynamic effects of production and/or injection lead to changes both within the reservoir and within the surrounding rock mass. It is important to emphasize, rock properties that control pore geometry also affect fluid movement and fluid distribution in the reservoir and the geomechanical modifications of these rock properties will affect flow patterns and ultimately the recovery 5,6 .…”