The Effect of Total Dissolved Solids and Permeability on the EOR Low Salinity Water Flooding

Abstract

Low salinity (LS) water flooding is an eminent enhanced oil recovery technique due to its performance, cost-effectiveness and the interesting results of oil recovery. To investigate the benefits of LS water in a different range of low permeable sandstone reservoir, different cores were sampled from different depths of the Bartlesville Sandstone Reservoir located in Eastern Kansas. Three pairs of cores were categorized based on their permeabilities. Four different brine salinities (formation water [FW] salinity is 104,550 ppm and others are diluted from FW) were examined for each pair to probe the role of both dissolved solids and permeability on the LS water performance. The core-flood results show that as the permeability decreases, the injection of LS water into cores not flooded with FW in the secondary stage is increased. The subsequent flooding of the four brines (including LS water) provided a higher oil recovery than injecting LS water alone regardless of the permeability. The oil recovery using only LS water flooding is higher than the combined FW-d2FW-d10FW flooding in all scenarios, and the highest was 8.93% of the OOIP. The oil recovery using only LS water flooding was higher than FW flooding in all scenarios, and the highest was 15.46% of the OOIP. On the other hand, the contact angle measurements show that the contact angle of the cores flooded with only LS water is lower than the other cores. This study demonstrates the importance of LS water in low permeable sandstone reservoirs.