An Approach to Inflow Control Device (ICD) Modelling to Delay Early Water Breakthrough in Heavy Oil Reservoirs in the Niger Delta

Abstract Developing reservoirs with viscosity ranges from 30 cp to 250 cp presents major challenges to Operators in terms of oil recovery per well due to the high viscosity and early water breakthrough. The challenges are low production rates (low productivity per foot) due to the viscosity of the field and early water breakthrough due to the higher relative mobility of water compared to the oil. To optimally develop these kinds of reservoirs, horizontal wells are required to maximise production rates. Inflow control devices have been used historically to improve inflow across the horizontal length of producing wells. For field BAC, we have analysed different options for ICD design using industry standard software, NETOOL, to evaluate the effect on recovery improvement and the delay in the onset of water production. Generally, the reservoirs in field BAC are shallow reservoirs with clean sands occurring in the Niger-delta between 2900 ftss to 5900 ftss. These sands, with strong aquifer supports have a history of early water breakthrough within the first 12 months of production. The reservoirs have very low solution gas oil ratios ≪ 100 scf/stb, high viscosities and densities hence they require artificial lift right from the onset of production. Four of the BAC reservoirs were evaluated for potential production improvement using ICDs and they are presented in this paper. The approach involved designing the wells without ICDs to ascertain recovery and water breakthrough timings. After which the wells were designed with ICDs using NETOOL and re-evaluated to review the effect on the recovery and water breakthrough. The incremental reward from the ICD designs for the varying viscosity ranges in four reservoirs (ABAC, BBAC, BBAC-7 and CBAC-3) were compared. The results showed incremental UR gains when ICDs were installed. Two of the four reservoirs considered have never been produced, the results for these two were generally positive. The other two reservoirs with production histories also showed improvements with ICDs. The ultimate recoveries also improved with decreasing viscosities based on the evaluation.