Simulation study analysis of the normal five-spot model and inverted five-spot polymer injection on X field

Increasing oil production has become the main focus in the oil and gas industry, so various methods are needed to increase oil recovery after production has decreased, one of which is polymer injection. The X field is located in Indragiri Hulu Regency. It has passed the secondary recovery stage, with an estimated oil-in-place reserve of 328,542.4 MSTB, recoverable reserve of 170,426.5 MSTB, recovery factor of 51.9%, and cumulative oil production of 135,856.8 MSTB. One of the activities that need to be carried out in chemical injection is to choose the right and efficient production-injection well pattern to be applied in the field. Therefore, a reservoir simulation study compared the normal and inverted five-spot patterns using variations in polymer concentrations of 500ppm, 1000ppm and 1500ppm and injection rates of 4000bpd, 5000bpd and 6000bpd. This study aims to determine the best scenario based on the largest oil recovery factor that can be applied to the X Field by looking at the cumulative change in oil obtained and the water cut. The simulation results show that the maximum cumulative oil value in the inverted five-spot model with a concentration of 1500 ppm and an injection rate of 6000 bpd is 69757.4 bbl, and the minimum water cut value in the inverted five-spot model with a concentration of 1500 ppm and an injection rate of 6000 bpd is 94.81 %. While the maximum value of cumulative oil in the normal five-spot model with a concentration of 1500 ppm and an injection rate of 6000 bpd is 310241bbl, and the minimum water cut value in the normal five-spot model with a concentration of 1500 ppm and an injection rate of 6000 bpd is 92.78%. This study shows that the higher the polymer concentration used, the higher the cumulative oil increase, followed by the higher water cut reduction, so the selection of the right polymer concentration is very important to increase oil recovery in the X field.