Enhanced Oil Recovery by Hydrophilic Silica Nanofluid: Experimental Evaluation of the Impact of Parameters and Mechanisms on Recovery Potential

Tariq Ali Chandio,Khalil Rehman Memon,Muhammad A Manan,Ghulam Abbas,Ghazanfer Raza Abbasi

doi:10.3390/en14185767

Abstract

Nanofluids as an EOR technique are reported to enhance oil recoveries. Among all the nanomaterial silica with promising lab results, economic and environmental acceptability are an ideal material for future applications. Despite the potential to enhance recoveries, understanding the two-fold impact of parameters such as concentration, salinity, stability, injection rate, and irreproducibility of results has arisen ambiguities that have delayed field applications. This integrated study is conducted to ascertain two-fold impacts of concentration and salinity on recovery and stability and evaluates corresponding changes in the recovery mechanism with variance in the parameters. Initially, silica nanofluids’ recovery potential was evaluated by tertiary flooding at different concentrations (0.02, 0.05, 0.07, 0.1) wt. % at 20,000 ppm salinity. The optimum concentration of 0.05 wt. % with the highest potential in terms of recovery, wettability change, and IFT reduction was selected. Then nano-flooding was carried out at higher salinities at a nanomaterial concentration of 0.05 wt. %. For the mechanism’s evaluation, the contact angle, IFT and porosity reduction, along with differential profile changes were analyzed. The recovery potential was found at its highest for 0.05 wt. %, which reduced when concentrations were further increased as the recovery mechanisms changed and compromised stability. Whereas salinity also had a two-fold impact with salinity at 30,000 ppm resulting in lower recovery, higher salinity destabilized the solution but enhanced recoveries by enhancing macroscopic mechanisms of pore throat plugging.

Highlights

IntroductionThe oil fields throughout major oil-producing regions are nearing the end of their useful life and unconventional reservoirs like shale requiring sophisticated techniques are still out of question at such low crude prices [1]
Enhanced oil recovery (EOR), known as tertiary recovery, is a process that aids in the recovery increment by enhancing recovery
The concern in nanofluid applications is its stability, and so physical observation of the solution will serve as a key indicator for staits stability, and so physical observation of the solution will serve as a key indicator for bility over time

Summary

Introduction

The oil fields throughout major oil-producing regions are nearing the end of their useful life and unconventional reservoirs like shale requiring sophisticated techniques are still out of question at such low crude prices [1]. As mature fields deplete and higher capital costs halt new projects, professionals’ emphasis has turned to enhance the ultimate recoveries of developed fields to meet the needs of the market. Existing EOR methods can recover 30–60% or more of the hydrocarbons, compared to 20–40% recovered by primary and secondary recovery methods [3]. EOR application in conventional and unconventional reservoirs is carried out using different techniques, whereby simple flooding by gas or water is carried out or a combination of methods, such as water alternating gas (WAG) or foam assisted water alternating gas, are used [4]

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