Development of a novel water shut-off test method: Experimental study of polymer gel in porous media with radial flow

Polymer gel treatment is an economic and effective method to reduce excessive water production in hydrocarbon reservoirs. However, there exist unsuccessful applications of polymer gel due to a mismatch of theoretical and experimental results in field conditions. In this study, a gel treatment experiment was implemented using a novel test method which includes a unique two-dimensional coreflooding setup and a new procedure of simultaneous oil and water injection. To form the gel in situ, a Cr(III)-acetate-hydrolyze polyacrylamide (HPAM) gelant was used. The results showed that polymer gel could be successfully applied to water shut-off (WSO) treatments in low-permeable porous media with radial flow. The residual resistance factors for oil and water were 78.50 and 1.96, respectively. Polymer gel also showed disproportionate permeability reduction (DPR) behaviour in coreflooding experiments. The flow resistance to water was 40 times greater than that to oil. In gel treatment, high gel selectivity (DPR scale) of 0.83 was measured by simultaneous oil and water flow to the core, and the determined oil cut was much greater than the water cut, whereas a lower well production rate led to a higher water cut. In addition, a water blockage problem was examined in simultaneous injection at constant pressure. No observation of water in the outlet was reported, though water saturation through the sandpack was increased to 84%. Finally, this paper suggests a new experimental test to increase the chances of successful WSO treatment under laboratory circumstances close to the field conditions.