Field application of engineered water injection in carbonate reservoirs under permeability channeling and gravity underride conditions

This paper investigates field-scale predictions of engineered water injection (EWI) technology in the secondary and tertiary injection modes. Three synthetic 5-spot reservoir models were considered: homogeneous reservoir, heterogeneous reservoir with permeability channeling, and heterogeneous reservoir with gravity underride. The predictions were conducted by upscaling recently history matched coreflood experiments. More so, sensitivity analysis and volumetric sweep efficiency estimation for all the three reservoir models using both tracer and fractional flow methods were investigated. The results showed that the EWI in the secondary mode outperformed other injection techniques (secondary formation water injection (FWI) and tertiary EWI) in all the three reservoir models. Also, the best volumetric sweep efficiency was achieved for the homogeneous reservoir model, followed by the channeling model and then the gravity underride model. Based on the EWI technique interpreted through geochemistry, it is believed that the main reason behind the incremental oil recovery is wettability alteration. This study gives more insight into understanding EWI technology through which field-scale developments can be performed with more certainty and lower risk.