Modeling, Application, and Optimization of Engineered Water Injection Technology in Carbonate Reservoirs.

Abstract

Abstract Engineered / low-salinity water injection (EWI/LSWI) technology is one of the latest and promising technology for improving recovery in both sandstone and carbonate reservoirs. In this paper, the mechanism, modeling, application, and optimization of EWI in carbonate reservoirs are discussed. Firstly, an EWI model based on multi-ion exchange is proposed and validated through history-matching of coreflood data. This proposed model is later tested on field-scale by upscaling the coreflood model to three 5-spot reservoir models including homogeneous, heterogeneous with channeling, and heterogeneous with gravity underride. Afterwards, a sensitivity and optimization studies are conducted using the machine learning and artificial intelligence tools in CMG-CMOSTTM. The results showed an improvement in both displacement and volumetric sweep efficiencies after engineered water injection, which was supported by mobility ratio and tracer method analyses. For the sensitivity study, oil price, tax rate, and initial oil saturation are among the most significant design parameters on EWI-NPV for the model investigated. More so, secondary EWI was recommended as opposed to tertiary injection due to the favorable recovery efficiency and profitability with respect to an NPV of $1.44 million and a payback period of about 2 years after the optimization study. This study gives more insight into understanding the EWI technology through which field-scale developments can be performed with more certainty and lower risk.