Compositional Modeling of Dimethyl Ether–CO2 Mixed Solvent for Enhanced Oil Recovery

Young Woo Lee,Jinhyung Cho,Moon Sik Jeong,Kun Sang Lee,Hye Seung Lee

doi:10.3390/app11010406

Young Woo Lee, Jinhyung Cho + Show 3 more

Open Access

https://doi.org/10.3390/app11010406

Copy DOI

Abstract

Dimethyl ether (DME) is a compound first introduced by Shell as a chemical solvent for enhanced oil recovery (EOR). This study aims to investigate the efficiency of EOR using the minimum miscible pressure (MMP) and viscous gravity number when a mixed solvent of CO2 and DME is injected. Adding DME to the CO2 water-alternating-gas process reduces the MMP and viscous gravity number. Reduction in MMP results in miscible conditions at lower pressures, which has a favorable effect on oil swelling and viscosity reduction, leading to improved mobility of the oil. In addition, the viscous gravity number decreases, increasing the sweep efficiency by 26.6%. Numerical studies were conducted through a series of multi-phase, multi-component simulations. At a DME content of 25%, the MMP decreased by 30.1% and the viscous gravity number decreased by 66.4% compared with the injection of CO2 only. As a result, the maximum oil recovery rate increased by 31% with simultaneous injection of DME and CO2 compared with only using CO2.

Highlights

As the discovery of new oil fields becomes increasingly difficult, most oil companies are focusing on maintaining economic oil prices through enhanced oil recovery (EOR)
According to previous studies that added liquefied petroleum gas (LPG) to CO2 flooding, LPG increases the displacement efficiency by reducing the minimum miscible pressure (MMP), which accelerates the effects of oil viscosity reduction, interfacial tension (IFT)
The vertical sweep efficiency according to the mole fraction of Dimethyl ether (DME) was compared using 2D reservoir modeling

Summary

Introduction

As the discovery of new oil fields becomes increasingly difficult, most oil companies are focusing on maintaining economic oil prices through enhanced oil recovery (EOR)technology to maximize the recovery from oil fields [1]. CO2 and hydrocarbon gas are widely used as injection fluids [3], wherein their contact with reservoir fluid causes viscosity reduction and oil swelling. Research using hydrocarbon gas or CO2 as a solvent has been conducted, from the laboratory to the field, for decades [3,5,6]. Research is being conducted to improve oil recovery and economic efficiency using a mixed solvent of CO2 and hydrocarbon gas or a surfactant [7,8,9,10]. According to previous studies that added liquefied petroleum gas (LPG) to CO2 flooding, LPG increases the displacement efficiency by reducing the minimum miscible pressure (MMP), which accelerates the effects of oil viscosity reduction, interfacial tension (IFT)

Objectives

Methods

Results

Conclusion