A Comprehensive Review on Low Salinity Water Injection for Enhanced Oil Recovery: Fundamental Insights, Laboratory and Field Studies, and Economic Aspects
Uma Sankar Behera, Jitendra S. Sangwai, Divya Baskaran, Hun‐Soo Byun
Abstract
Oil and gas are expected to continually dominate our lives in the foreseeable future until a sustainable energy transition to renewable energy is achieved. The increasing energy demand needs to be met by improving crude oil recovery from mature oilfields using various enhanced oil recovery (EOR) methods. Among various EOR methods, low salinity water injection (LSWI) has emerged as a cost-effective method compared with more expensive methods, such as thermal, chemical, and gas injection. Several mechanisms have been proposed to explain the low salinity effect, but the exact processes governing oil recovery in both sandstone and carbonate reservoirs remain unclear. Particularly, discrepancies between laboratory and field results, along with pilot test failures, may suggest a shift toward hybrid LSWI-EOR techniques, including the integration of CO 2 injection and CO 2 sequestration, which aligns with the goals of carbon neutrality and CO 2 utilization. Hybrid LSWI methods which combine low salinity water with surfactants, nanoparticles, and polymer demonstrate significant potential for EOR compared to standalone LSWI. These hybrid methods contribute to the mitigation of climate change by optimizing the compositions of hybrid injection fluid, and this field has been scarcely covered in previous review articles. This review critically evaluates the potential of LSWI along with various mechanisms of LSWI, identifying macroscale factors influencing oil recovery and presenting findings from laboratory and field studies. Additionally, this paper assesses desalination techniques for obtaining low salinity water and evaluates the economic viability of LSWI, an often overlooked topic. This paper provides in-depth insights into the development of LWSI-EOR methods at the field scale, contributing to the transition toward more sustainable energy practices.