Determination of Water Drive Mechanism Activation Using Geological Model for Heavy Oil Field in North of Iraq

Abstract

Most of the productive oil fields around the world are water drive reservoirs where water influx has the potential to improve oil recovery considerably. Verifications are required to illustrate the aquifer activation and this needs assessment programs to include diagnosis, classifications and aquifer characterization using mathematical models for accurate simulation of the aquifer behavior. In Qaiyarah Oil Field, there is a big lack in subsurface data to confirm the aquifer's level of activity although there are some traces of water production from the wells located at the southwest of the field. Based on this fact, a base case simulation has run through making history match for the production and reservoir pressure to confirm the activation of the aquifer. The results showed a fast decline in the reservoir pressure which mismatched the current measured pressure from the field. This led to adopt the option of modelling a simulated properties aquifer to match the production and pressure from the field in a step to confirm the aquifer activation. The simulation had re-run with multi trials to approve the aquifer strength, geological and reservoir properties. Finally, history match showed perfect matching on production and pressure through selecting edge aquifer model that matched with the available subsurface data from the field. The cumulative production till the end of 2021 was calculated to be 47,142,257 bbls and reservoir pressure was 387 Psi, which almost match the measured cumulative production from the field that was 47,100,000 bbls and reservoir pressure of 389 Psi which was considered a very acceptable match.