Three-Phase Fluid Flow Interaction at Pore Scale during Water- and Surfactant-Alternating Gas (WAG/SAG) Injection Using Carbon Dioxide for Geo-Sequestration and Enhanced Oil Recovery

Abstract

Sequestration of CO2 in geologic formations such as depleted oil reservoirs has emerged as one of the lead solutions to tackle greenhouse gas emissions to reduce pollution and global warming. Supercritical CO2 (sc-CO2) injection in oil reservoirs has proven to be useful as an enhanced oil recovery (EOR) technique along with the benefits of CO2 sequestration. In this study, a tortuous microscopic pore scale model was used to study and investigate the phenomena of water-alternating gas (WAG) and surfactant-alternating gas (SAG) with sc-CO2. The study scrutinizes the dynamics of the pore-level phenomenon in the multiphase WAG and SAG flows at the pore level in detail. Transient computational fluid dynamics (CFD) analysis was used to study the fluid flow characteristics of oil, water, and sc-CO2 at different reservoir pressure and temperature conditions in oil-wet conditions. Governing equations were coupled with EOS (Helmholtz free energy equation) to capture the viscous and intrinsic properties of sc-CO2 due to variations in pressure and temperature conditions. It was found that higher oil recovery does not necessarily indicate higher sc-CO2 sequestration and that temperature harms the displacement mechanism due to unfavorable mobility ratios. Comparing WAG and SAG for the first injection cycle, SAG showed a more diffused interface between displaced and displacing fluid. The additional oil recovery produced in patches was a result of pressure oscillations near the blind pores. Moreover, high vorticity promotes greater intermixing between the displacing and displaced fluid by increasing the rate of interface length. In SAG cases, faster sc-CO2 breakthroughs were observed due to reduced shear stress along the fluid interfaces, which resulted in higher sequestration values in a given time frame. The CO2 sequestration volume in SAG cases was found to be approximately 40% more than in WAG experiments. The study confirms that lower values of oil–water interfacial tension aids in faster and more efficient sequestration of sc-CO2 along with additional oil gain from a given reservoir.

A Review on the Recent Scientific and Commercial Progress on the Direct Air Capture Technology to Manage Atmospheric CO2 Concentrations and Future Perspectives

“…Several issues, such as global warming, acid rain, and smog formation have been raised that have never been thought about before climate change. Most concerning among these issues is global warming, caused by greenhouse gases, mostly carbon dioxide (CO 2 ) . Emission of these greenhouse gases is primarily due to fossil fuel combustion, biomass gasification, chemical industries, construction activities, large power plants, and industrial activities and also from natural and fugitive emissions.…”

“…Emission of these greenhouse gases is primarily due to fossil fuel combustion, biomass gasification, chemical industries, construction activities, large power plants, and industrial activities and also from natural and fugitive emissions. Nearly all countries have decided to reduce global temperature rise below 2 °C under the Paris Climate Agreement to confront global warming challenges. , To accomplish climate goals, countries collectively need to reduce 10 billion metric tons of CO 2 per year (GtCO 2 yr –1 ) currently and the projected 20 GtCO 2 yr –1 after 2050. , Energy management, extensive decarbonization, and deployment of negative emissions technologies (NETs) are essential in achieving climate change targets. In the battle against human-induced climate change, NETs must no longer be considered the last option; they must be used in industries where decarbonization is difficult .…”

“…Most concerning among these issues is global warming, caused by greenhouse gases, mostly carbon dioxide (CO 2 ). 1 Emission of these greenhouse gases is primarily due to fossil fuel combustion, biomass gasification, chemical industries, construction activities, large power plants, and industrial activities and also from natural and fugitive emissions. Nearly all countries have decided to reduce global temperature rise below 2 °C under the Paris Climate Agreement to confront global warming challenges.…”

“…2,3 To accomplish climate goals, countries collectively need to reduce 10 billion metric tons of CO 2 per year (GtCO 2 yr −1 ) currently and the projected 20 GtCO 2 yr −1 after 2050. 1,2 Energy management, extensive decarbonization, and deployment of negative emissions technologies (NETs) are essential in achieving climate change targets. In the battle against humaninduced climate change, NETs must no longer be considered the last option; they must be used in industries where decarbonization is difficult.…”

Influence of Reservoir Spatial Heterogeneity on a Multicoupling Process of CO2Geological Storage

“…Greenhouse gas emissions from 2009 to 2019 were higher than in any previous decade, and limiting global warming is a huge challenge . Injecting carbon dioxide (CO 2 ) into geological structures is a technology that can effectively reduce CO 2 emissions. − There are currently a lot of research studies on various application scenarios of carbon capture, utilization, and storage (CCUS). − However, the geological structure naturally has spatial heterogeneity, and this spatial heterogeneity is usually manifested as the difference in reservoir rock properties such as reservoir rhythm, permeability, porosity, and capillary parameters. − At the same time, there may be interlayers in the reservoir, which divide the reservoir into multiple small layers with fluid and pressure discontinuity. , The spatial heterogeneity of the reservoir will significantly affect the flow and heat transfer of CO 2 . Thus, studying the influence of reservoir spatial heterogeneity on CO 2 storage is of critical significance when selecting a site for CO 2 geological storage, predicting fluid state, and optimizing engineering parameters.…”