Performance Assessment of Songo Songo Gas Field: Dynamic Approach

Abstract

The primary purpose of this work is to evaluate the dynamic performance of the Songo Songo gas field through tuning the model to characterize reservoir performance. The work is dedicated on evaluation of aquifer activity and the effects of reservoir compartments connectivity onto field performance to assess the long term production. Full field multidimensional numerical simulation models with updated data have been performed using Imex - CMG software.This study was conducted in Songo Songo gas field located off the coast of Tanzania mainland in East Africa. Data file to conduct the simulations study obtained from PAET whereby three situations has been assessed; aquifer activity analysis and its effect on pressure maintenance, volumetric depletion study and the influence of reservoir compartments onto field performance. Two sections (central and peripheral) of the reservoir were designed to further investigate the field performance.It was concluded that there are basically three potentially hydrocarbon drainage areas in the Songo Songo field named SSC, SSE and SSN. The field is isolated and perform volumetrically in its early time of production. Further analysis confirms the possibility of performing as connected reservoirs whereas the central section (SSC and SSE) is surrounded by the peripheral section (SSN) with lower permeability. The peripheral section charge fluids (gas and water) via a narrow contact window to the central section to provide the current historical data pressure behaviour. On the basis of this study, it can be recommended that geology of the entire outer surface of the reservoir should be examined carefully to identify communicating pathways. If no communicating pathways exist, the reservoir can be confidently discounted as a possible water drive otherwise it remain a candidate of water drive. Also, further seismic study or review in conjunction with micro-structural information from the high resolution core has to be conducted to keenly analyse the intra fault behaviour between peripheral section and central section of a reservoir.