Optimizing Injection Rate Through Ratio Data Method for Improved Oil Recovery Processes of Oil Rim Reservoirs (Published)
A decrease in the volume of the reservoir`s original oil in place has been occasioned by long periods of hydrocarbon withdrawals; the oil and gas industry is bent on economic withdrawal to recoup investments and thus is engrossed in producing more of the trapped oil in the reservoir. The employment of water flooding and polymer flooding to recover most of the residual oil is associated with water production. This study investigates among other things the effect of placing the injection well close to a high permeable layer in a heterogeneous mature field during flooding processes. The study was performed with the aid of Eclipse 100 Reservoir software. A synthetic heterogeneous reservoir model characterized by (28 x 28 x 1) grid cells with dimensions 300 x 300 x 60ft in the X, Y, and Z coordinates. The reservoir permeability ranges from 2804 mD to 3136 mD. The datum depth of the reservoir is 8000 ft and pressure at the datum depth is 4000 psi, to depict a mature reservoir, the reservoir has an oil column thickness of 60ft, the Gas-Oil contact, and Water-Oil contact are at the datum depth of 8000ft and 8060 ft respectively. The injection rates for both water and polymer flooding were 1000, 4000, 7000, 10000, 13000, and 16000 STB/day. The simulation results for water flooding and polymer flooding were obtained and analyzed. The study applied the ratio data method to analyze the simulation result for optimum injection rate. The outcome indicated that the ratio of oil to water produced is higher at the injection rate of 1000Stb/d for both water and polymer flooding scenario. Conclusively, optimum injection rates are ideal during improved oil recovery processes. However, an infinitesimal increment of optimum injection rate will recover more oil without upsetting the water-cut ratio marginally considering the adverse effect of produced water such as the disposal cost, and equipment degradation. Furthermore, the simulation revealed that Injection wells closer to high permeable layers in a heterogeneous reservoir aid sweep efficiency of displacing fluid but also account for higher water production due to early breakthrough of water, and at higher injection rates, less oil was produced due to the unfavorable mobility ratio.
Keywords: injection rate, injection well, mature wells, oil production, polymer flooding, water flooding, water production