Oil Recovery by Polymer Flooding; Sensitivity Analysis to Technical Parameters

Numerous enhanced oil recovery techniques including miscible gas injection, chemical, thermal and other methods are applied at the third phase of production after both primary and secondary recovery have been exhausted. Polymer flooding is one of the chemical methods that recover more oil by decreasing the mobility of the system; by increasing the viscosity of the injected water that results in an improvement in the volumetric sweep efficiency. The objective of this work is to asses and select the development options using polymer process that maximize oil recovery for a synthetic reservoir model where technical parameters are optimized thoroughly. Reservoir simulation study using ECLIPSE 100 was used to simulate the synthetic model to investigate the different development options of polymer flooding applied and compare them to waterflooding. The development options include continuous polymer injection, water alternating polymer, and polymer slug injection. Through the study, the effect of injection rate, polymer concentration, slug size, and well completion were investigated by setting up a range of sensitivities. According to the sensitivity analysis performed on injection rate when waterflooding is applied; 1500STB/D was considered the most suitable operating injection rate for the study. Results of the study reveal a general trend of improved oil recovery with the implementation of polymer flooding over waterflooding in the range of 3 – 8%. In the continuous polymer injection, the highest field oil efficiency of more than 50% was obtained using polymer concentration of 200 ppm where all the layers were completed. On the other hand employing the water alternating polymer technique, a maximum oil recovery was achieved at 200 ppm polymer concentration, three months of WAP cycle, and using the same completion as in the continuous process. Results also indicated that both continuous and polymer slug injection have the same optimum concentration of 200 ppm. Furthermore, the study recommends using well completion one, two years of polymer slug injection, and polymer concentration of 1000 ppm. The selected system yields an oil recovery of 49.26%. The outcomes of this work should assist the oil industry in planning polymer flooding for heterogeneous reservoirs; keeping in mind that UAE hydrocarbon reservoirs are normally complex with high degree of heterogeneity

Oil recovery by flooding; sensitivity analysis to technical parameters

Numerous enhanced oil recovery techniques including miscible gas injection, chemical, thermal and other methods are applied at the third phase of production after both primary and secondary recovery have been exhausted. Polymer flooding is one of the chemical methods that recover more oil by decreasing the mobility of the system; by increasing the viscosity of the injected water that results in an improvement in the volumetric sweep efficiency. The objective of this work is to asses and select the development options using polymer process that maximize oil recovery for a synthetic reservoir model where technical parameters are optimized thoroughly. Reservoir simulation study using ECLIPSE 100 was used to simulate the synthetic model to investigate the different development options of polymer flooding applied and compare them to waterflooding. The development options include continuous polymer injection, water alternating polymer, and polymer slug injection. Through the study, the effect of injection rate, polymer concentration, slug size, and well completion were investigated by setting up a range of sensitivities. According to the sensitivity analysis performed on injection rate when waterflooding is applied; 1500 STB/D was considered the most suitable operating injection rate for the study. Results of the study reveal a general trend of improved oil recovery with the implementation of polymer flooding over waterflooding in the range of 3 - 8%. In the continuous polymer injection, the highest field oil efficiency of more than 50% was obtained using polymer concentration of 200 ppm where all the layers were completed. On the other hand employing the water alternating polymer technique, a maximum oil recovery was achieved at 200 ppm polymer concentration, three months of WAP cycle, and using the same completion as in the continuous process. Results also indicated that both continuous and polymer slug injection have the same optimum concentration of 200 ppm. Furthermore, the study recommends using well completion one, two years of polymer slug injection, and polymer concentration of 1000 ppm. The selected system yields an oil recovery of 49.26%. The outcomes of this work should assist the oil industry in planning polymer flooding for heterogeneous reservoirs; keeping in mind that UAE hydrocarbon reservoirs are normally complex with high degree of heterogeneity