Experimental investigation of asphaltene-augmented gel polymer performance for water shut-off and enhancing oil recovery in fractured oil reservoirs

Abstract

In this study, performance of hydrolyzed polyacrylamide (HPAM) cross-linked with polyethylenimine (PEI) gel polymer system along with a novel composite profile system of the same gel polymer system blended with asphaltene particles (asphaltene-augmented gel polymer) is investigated for enhancing oil recovery and water shut-off during water flooding in fractured oil reservoirs by employing one-quarter of a five-spot glass micromodel. For this purpose, suitable conditions in terms of gelation time, gel strength and stability for such polymer systems are experimentally determined via disparate static tests. The system with such conditions is then incorporated to perform dynamic experiments in fractured micromodels where significant factors including physical fracture characteristics and pore shape geometry are investigated. Oil recovery factors are specified against injected water pore volume through image analysis technique, which was conducted on high-resolution micromodel images. Results implied that incorporation of asphaltene-augmented gel polymer system than gel polymer system imposes higher final oil recovery factor as well as later water breakthrough, since the gel strength in asphaltene-augmented gel system is more than the gel system, which therefore results in more effective fracture impediment. The results also demonstrated the dependency of pre-implemented gel polymer and/or asphaltene-augmented gel polymer water injection performance on pore shape geometry and fracture physical properties. This study could aid petroleum engineers in comprehension of fracture and pore characteristics effects on controlling unwanted water production via gel polymer in fractured reservoirs.