3D Reservoir Simulation of X Field Onshore Niger Delta Nigeria: The Power of Multiple Iterations

Abstract The re-development of brown fields traditionally depend on the extensive and proper integration of all subsurface Petroleum Engineering data. This paper demonstrates the impact and importance of incorporating feedback from dynamic reservoir modeling, in particular the history matching of calibrated production data, into the static model building thus creating an integrated static/dynamic modelling (loop) process. This case study describes the subsurface modelling work done for a 67 ft oil-rim reservoir with a large gas-cap in the Niger Delta (Nigeria). The reservoir has been on production since the early 90s and till date has produced over 30MMstb of oil. The first-pass static model was constructed based on consistent geologic concepts incorporating data from 3D seismic and well logs. Initial simulation and history matching of this model suggested that the historical production from the reservoir could only be reasonably matched with higher oil volumes in place compared to the original Base Case Model. The static model was subsequently updated, by re-evaluation of the structural uncertainties as well as an update of the property modeling. The new model, whilst still consistent with the hard data (wells and seismic) achieved a high confidence history match. Based on the revised model, six new wells are planned to be drilled in this reservoir in 2011 to develop additional over 20MMstb of oil reserve. The integration between the various Petroleum Engineering disciplines (Production Geology / Seismology, Petrophysics, Reservoir Engineering and Production Technology) and the use (early) of dynamic results to guide the update of the static model proved powerful. This "closing the loop" approach results in a better understanding of the subsurface, delivers more robust results in optimal placement of wells and ultimately enables a more optimal development of the field.