Perpustakaan Digital ITB

The use of EOR has been widely researched and carried out in various reservoirs throughout the world, one of which is the use of Low Salinity Water Flood (LSWF). The application of LSWF as tertiary flooding can increase the efficiency of water in invading oil remaining in the reservoir so that more oil recovery can be obtained. If investigated further, the application of LSWF as tertiary flooding can also be used in steady-state conditions which combine displacement, stratification and variable injectivity mechanisms in 5-spot pattern wells in solution-gas-drive reservoirs. This method creates reservoir modeling in solution-gas-drive by comparing Hard Salinity Water Flood (HSWF) and LSWF as secondary waterflooding. This model will be analyzed for sensitivity to water production rate, water injection rate, and oil recovery on (i) permeability; (ii) mobility ratio; (iii) LSWF; and (iv) a combination of several sensitivity analyses. Sensitivity analysis on permeability was applied to three different values but had the same ratio. Sensitivity analysis on the mobility ratio is applied based on different oil and water viscosity values but have the same ratio between viscosities, and the same mobility ratio value is applied but different oil and water viscosity values. LSWF sensitivity analysis is applied based on the total volume of injected pore water. A combination of sensitivity analysis was applied by randomly combining two of the three existing analyzes and combining the three analyzes into one. The results of sensitivity analysis on permeability show that increasing permeability with a ratio of 5 times, oil recovery, production rate and water injection rate also increase with a ratio of 5 times. The results of the sensitivity analysis on the mobility ratio show that high viscosity values of water (?w > 0.5 cP, M < 1.75) and/or oil (?o > 1 cP, M > 1.75) obtain lower oil recovery, production rates and water injection rates (Np < 200000 STB, qw < 3500 STB/D) than the standard viscosity of each fluid (?w = 0.5 cP, ?o = 1 cP, M = 1.75, Np = 200099.8 STB, qw = 3792.4 STB/D). When the viscosity value of water (?w < 0.5 cP, M > 1.75) and/or oil (?o < 1 cP, M < 1.75) is low, the oil recovery value, production rate and water injection rate obtained are higher (Np > 200000 STB, qw > 3500 STB/D) than the standard viscosity value of each fluid. When oil viscosity >> water viscosity (?o/?w ? 8), then fingering occurs which reduces oil recovery (Np = 198624.3 STB), but increases the production rate and water injection rate (qw = 4252 STB/D) when compared to standard viscosity each fluid. The results of the sensitivity analysis on air salinity show that LSWF has a major effect in increasing oil recovery by 25.62%, reducing the water production rate by a difference of 639.9 STB/D, and reducing the water injection rate by a difference of 640.8 STB/D when compared to HSWF. The combined results of sensitivity analysis show that LSWF has more influence in reducing water production rate & water injection rate at low water viscosity (?w < 0.5 cP, M > 1.75) and increasing oil recovery at high oil viscosity (?o > 1 cP, M > 1.75). LSWF is also more influential in increasing water production rate & water injection rate at low permeability (k = 10 md). The high viscosity of each fluid (?w = 2 cP, ?o = 8 cP, M = 3.5) is more influential in reducing the air production rate (qw around 1208.5-6070.5 STB/D) and the water injection rate (1208.6 – 6070.2 STB/D) at high permeability (k = 250 md) against the remaining fluid viscosity data (?w < 2 cP, ?o < 8 cP) & high permeability (k = 250 md).