Experimental investigation of permeability heterogeneity impact on the miscible alternative injection of formation Brine–Carbon dioxide

Abstract

Water alternating gas injection is considered as efficient enhanced oil recovery techniques to increase oil cumulative production rate. The objective of this comprehensive study is to measure the profound impact of different permeability heterogeneities on the ultimate recovery factor of miscible alternative injection of formation brine–carbon dioxide processes. To evaluate the results of each heterogeneity types, three heterogeneity levels of homogeneous, layered, and composite were taken into consideration, and the ultimate recovery factor was explicitly investigated for each case. The ultimate oil recovery factor for the homogeneous sample had witnessed the highest value at the permeability ratio of 1 (about 86.4%). According to the results of this experiment, miscible water alternating gas (henceforth; WAG) injectivity as a secondary enhanced oil recovery (henceforth; EOR) mode provided higher recovery factor due to the higher interfacial contact among in-situ oil, carbon dioxide and higher values of permeability ratios have led to lower ultimate recovery factor. After the breakthrough, the impact of permeability sequence and heterogeneity had caused to differ the results of recovery factor for each scenario. It was about 90.4% for the homogeneous sample, 86.5% and 83.8% for the low-high-low and high-low-high respectively. Consequently, in the absence of crossflow, the recovery factor had provided higher values rather than crossflow presence.