Experimental Investigation of Kaolinite Clay Role in Low Salinity Water Flooding: A Micromodel Study

Water flooding is one of the most important enhanced oil recovery (EOR) methods in the world. It has been successfully implemented in many oilfields. Low salinity water flooding (LSWF) has been recognized as one of the promising methods for enhanced oil recovery of clay-rich sandstone reservoirs. Many studies have shown that LSWF has an important role in formations with sufficient amount of clay. However, different hypotheses that have been proposed for oil recovery due to LSWF mechanisms are not completely accepted, and they need more investigation due to controversial response to LSWF. Thus, there is not a general agreement for mechanisms behind low salinity effects and associated problems such as fines migration and formation damage. In this study, 2-D glass micromodels (clean and clay-coated) and crude oil from an Iranian oilfields were used to visualize the effect of lowering injected water salinity (30000 ppm, 4000 ppm, 2000 ppm and DI water) on fines migration and improved oil recovery. In addition, single phase flow test was performed to evaluate possible fines migration with the same salinities. Results indicate an increase in recovery for both clay-coated and clay-free systems while additional oil recovery during LSWF in clay-coated micromodel was more significant (3.07%) comparing to that for clay-free micromodel (1.89%). Fines migration was observed during both single- and two-phase flow experiments.