Influence of confinement effect on recovery mechanisms of CO2-enhanced tight-oil recovery process considering critical properties shift, capillarity and adsorption

Wu, Shouya; Li, Zhaomin; Sarma, Hemanta Kumar

doi:10.1016/j.fuel.2019.116569

Cited by 23 publications

(14 citation statements)

References 37 publications

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“…However, other pore scale processes can affect the efficiency of CO2 EOR scenarios in ultra-tight rocks 54 . The diffusion of CO2 into liquid-rich shales would trigger processes such as asphaltene precipitation [61][62][63] , nano-pore capillary confinement and condensations [64][65][66] , relative adsorption of different components in kerogen and clay rich formations 67 , and geomechanical effects 55 .…”

Section: Methodsmentioning

confidence: 99%

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs

Mahzari

Jones

Oelkers

2020

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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Carbon dioxide injection in shale reservoirs can be beneficial for enhanced oil recovery and CO2 storage scenarios. CO2 mass transfer can be influenced strongly by the in-situ liberation of light oil components from live oil forming a distinct gas phase. This mechanism has been overlooked in the past for studying CO2 and oil interactions in tight formations. In this work, a series of analytical solutions and numerical simulations were developed to identify the effect on EOR by CO2 due to the liberation of a light hydrocarbon gas phase from live oil in shales. The analytical model demonstrated faster diffusion of CO2 in the two-phase system due to the presence of this gas phase. Using numerical approaches, laboratoryscale simulations indicated that in-situ gas formation can increase oil recovery by 35%. At the field-scale, an additional oil recovery of 9.8% could be attained. Also, the CO2 storage capacity of shale formations could be significantly enhanced due to capillary trapping of CO2 in the liberated gas. The results of this study could potentially be used to improve evaluations of the potential of CO2 EOR in shale reservoirs.

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Section: Methodsmentioning

confidence: 99%

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs

Mahzari

Jones

Oelkers

2020

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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“…It is defined as the minimum pressure where the injected gas and the oil phase have no obvious interface and then become miscible with each other [58]. A series of PVT and core flooding tests have validated that CO 2 is much easier to become miscible with crude oil than other gases including flue gas, natural gas, and nitrogen [59]. Based on the calculation of phase equilibrium, we obtain the MMP at different CO 2 injection ratios.…”

Section: Minimum Miscible Pressure (Mmp)mentioning

confidence: 99%

Nanopore Confinement Effect on the Phase Behavior of CO2/Hydrocarbons in Tight Oil Reservoirs considering Capillary Pressure, Fluid-Wall Interaction, and Molecule Adsorption

Zheng

2021

Geofluids

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The pore sizes in tight reservoirs are nanopores, where the phase behavior deviates significantly from that of bulk fluids in conventional reservoirs. The phase behavior for fluids in tight reservoirs is essential for a better understanding of the mechanics of fluid flow. A novel methodology is proposed to investigate the phase behavior of carbon dioxide (CO2)/hydrocarbons systems considering nanopore confinement. The phase equilibrium calculation is modified by coupling the Peng-Robinson equation of state (PR-EOS) with capillary pressure, fluid-wall interaction, and molecule adsorption. The proposed model has been validated with CMG-Winprop and experimental results with bulk and confined fluids. Subsequently, one case study for the Bakken tight oil reservoir was performed, and the results show that the reduction in the nanopore size causes noticeable difference in the phase envelope and the bubble point pressure is depressed due to nanopore confinement, which is conductive to enhance oil recovery with a higher possibility of achieving miscibility in miscible gas injection. As the pore size decreases, the interfacial tension (IFT) decreases whereas the capillary pressure increases obviously. Finally, the recovery mechanisms for CO2 injection are investigated in terms of minimum miscibility pressure (MMP), solution gas-oil ratio, oil volume expansion, viscosity reduction, extraction of lighter hydrocarbons, and molecular diffusion. Results indicate that nanopore confinement effect contributes to decrease MMP, which suppresses to 650 psi (65.9% smaller) as the pore size decreases to 2 nm, resulting in the suppression of the resistance of fluid transport. With the nanopore confinement effect, the CO2 solution gas-oil ratio and the oil formation volume factor of the oil increase with the decrease of pore size. In turn, the oil viscosity reduces as the pore size decreases. It indicates that considering the nanopore confinement effect, the amount of gas dissolved into crude oil increases, which will lead to the increase of the oil volume expansion and the decrease of the viscosity of crude oil. Besides, considering nanopore confinement effect seems to have a slightly reduced effect on extraction of lighter hydrocarbons. On the contrary, it causes an increase in the CO2 diffusion coefficient for liquid phase. Generally, the nanopore confinement appears to have a positive effect on the recovery mechanisms for CO2 injection in tight oil reservoirs. The developed novel model could provide a better understanding of confinement effect on the phase behavior of nanoscale porous media in tight reservoirs. The findings of this study can also help for better understanding of a flow mechanism of tight oil reservoirs especially in the case of CO2 injection for enhancing oil recovery.

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“…Carbon dioxide injection has the advantages of wide application, low cost, significantly improved oil recovery [10][11][12]. At the same time, carbon dioxide flooding can solve the problem of carbon dioxide sequestration to a certain extent, reduce greenhouse gas emissions into the atmosphere, and alleviate the pressure of the environmental pollution [13][14][15][16][17][18]. So under the background of energy shortage, energy conservation and emission reduction, carbon dioxide flooding has a broad application prospect [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Research for reducing the Minimum Miscible Pressure of crude oil and carbon dioxide by injecting citric acid isobutyl ester

Fan

Zhao

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Carbon dioxide miscible flooding has become one of the important technologies for improving oil recovery. The Minimum Miscible Pressure (MMP) is the key parameter to realize miscible flooding. As the MMP in the research area is higher than the formation fracture pressure, miscible flooding cannot be formed. To address this problem, it is necessary to find a way to reduce the MMP. Citric acid isobutyl ester is chosen to reduce the MMP of carbon dioxide and crude oil in this research. The effect of citric acid isobutyl ester on reducing the MMP was measured by the method of long-slim-tube displacement experiment. The experiment results show that the MMP is 29.6 MPa and can be obviously reduced by injecting the slug of citric acid isobutyl ester. The MMP could decrease gradually with constantly adding the injected slug of citric acid isobutyl ester, but the decrease becomes smaller and smaller. The optimum injected slug size of the chemical reagent is 0.003 PV. Under the condition of the slug size, the MMP is reduced to 23.5 MPa and the reduction is 6.1 MPa.

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Influence of confinement effect on recovery mechanisms of CO2-enhanced tight-oil recovery process considering critical properties shift, capillarity and adsorption

Cited by 23 publications

References 37 publications

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs

Nanopore Confinement Effect on the Phase Behavior of CO2/Hydrocarbons in Tight Oil Reservoirs considering Capillary Pressure, Fluid-Wall Interaction, and Molecule Adsorption

Research for reducing the Minimum Miscible Pressure of crude oil and carbon dioxide by injecting citric acid isobutyl ester

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Influence of confinement effect on recovery mechanisms of CO2-enhanced tight-oil recovery process considering critical properties shift, capillarity and adsorption

Cited by 23 publications

References 37 publications

Impact of in-situ gas liberation for enhanced oil recovery and CO2 storage in liquid-rich shale reservoirs

Impact of in-situ gas liberation for enhanced oil recovery and CO2 storage in liquid-rich shale reservoirs

Nanopore Confinement Effect on the Phase Behavior of CO2/Hydrocarbons in Tight Oil Reservoirs considering Capillary Pressure, Fluid-Wall Interaction, and Molecule Adsorption

Research for reducing the Minimum Miscible Pressure of crude oil and carbon dioxide by injecting citric acid isobutyl ester

Contact Info

Product

Resources

About

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs

Impact of in-situ gas liberation for enhanced oil recovery and CO₂ storage in liquid-rich shale reservoirs