Dynamic track model of miscible CO2 geological utilizations with complex microscopic pore-throat structures

Wang, Hengli; Tian, Leng; Huo, Ming-hui; Xu, Shuwen; Liu, Zongke; Zhang, Kaiqiang

doi:10.1016/j.fuel.2022.124192

Cited by 7 publications

(3 citation statements)

References 34 publications

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“…6c presented the oil recovery in miscible/immiscible flooding, and we could see that the oil recovery of miscible flooding was 52.91%, more than twice that of immiscible flooding which was constant to the experimental results. Moreover, the oil recovery curves of CO2 flooding exhibited three periods, which could be divided into pure oil, diffusion and pure CO2 area [21] . In CO2 miscible flooding, during pure oil area, oil recovery curve was an approximate straight line, and there is no gas production.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Characterization of CO2 miscible/immiscible flooding in low-permeability sandstones using NMR technology and VOF method

Wenlian¹,

Xiao²,

Ren³

et al. 2023

Preprint

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CO2 flooding is considered as one of the most effective enhanced oil recovery (EOR) methods in lowpermeability reservoirs. In our work, we studied CO2 miscible/immiscible flooding in low-permeability sandstones, using nuclear magnetic resonance (NMR) and volume of fluid (VOF) method. The experimental results indicated that the oil recovery after CO2 miscible flooding is 68.13%, which is twice as much as the one after CO2 immiscible flooding; oil in large pores is mainly displaced in the process of CO2 immiscible flooding, whereas in the case of CO2 miscible flooding, the oil comes from all kinds of pores. On the basis of VOF simulation results, it was fond that oil recovery after CO2 miscible flooding is also two times the one after CO2 immiscible flooding, which are dependent on the characteristic of CO2-oil contact. Moreover, oil recovery of CO2 miscible/immiscible flooding significantly decreased with the increase of oil viscosity. The interesting observation is that piston displacement happened at the injection part and finger displacement did at the production part during CO2 miscible flooding. In the end, we found that CO2 storage rate of miscible flooding is higher than that of immiscible flooding, and CO2 storage rate also significantly decreased with the increase of oil viscosity.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Characterization of CO2 miscible/immiscible flooding in low-permeability sandstones using NMR technology and VOF method

Wenlian¹,

Xiao²,

Ren³

et al. 2023

Preprint

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“…Adequate scheduling of water injection can mitigate gas invasion and prolong the duration of miscible flooding under high gas-oil ratios [32,33]. The optimal timing for implementing WAG flooding after CO 2 flooding in pure oil reservoirs is still uncertain [34][35][36]. As depicted in Figure 1, the timing of WAG flooding intervention is linked to the degree of heterogeneity, indicating a possible optimal intervention timing [37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Research on the Timing of WAG Intervention in Low Permeability Reservoir CO2 Flooding Process to Improve CO2 Performance and Enhance Recovery

Zhao,

Sang,

Ding

et al. 2023

Energies

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In low permeability reservoirs, CO2 flooding usually leads to gas channeling, whereby a significant amount of CO2 bypasses the oil-bearing formation and fails to effectively displace oil. Introducing water-alternating-gas (WAG) flooding, utilizing water phase stability-driven processes, serves to suppress gas channeling and enhance oil recovery rates. Implementing WAG flooding, which utilizes water phase stability-driven processes, helps suppress gas channeling and improve oil recovery rates. The timing of implementing WAG flooding is crucial. Initiating WAG flooding prematurely can limit the efficiency of CO2 displacement, while initiating it with delays may result in severe gas channeling, resulting in decreased production and increased environmental risks. Finding the balance point is the challenge. The balance point can effectively control gas channeling without reducing the efficiency of CO2 flooding. In this paper, the timing of WAG flooding in low permeability reservoirs is studied in detail. Firstly, this study conducted experimental research to investigate the CO2 displacement process in both homogeneous and heterogeneous cores. Furthermore, it validated the correlation between the timing of WAG injection and the heterogeneity of the cores. The experimental results indicated the existence of an optimal timing for WAG injection, which is correlated with the degree of heterogeneity. Numerical simulation studies were performed to simulate the characteristics of the light oil–CO2 system using the Peng–Robinson (PR) equation. Furthermore, a history matching analysis was performed to validate the experimental results and investigate the correlation between WAG injection and the degree of heterogeneity. The study concluded that as the degree of heterogeneity increases, initiating WAG injection earlier leads to a more significant suppression of gas channeling, increased water–gas interaction, improved gas–oil contact, and enhanced the synergistic effect of increasing the resistance and pressure of WAG flooding and controlling gas channeling. This finding has significant practical implications, as the optimization of WAG injection timing can enhance oilfield production efficiency.

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“…Therefore, many newly discovered low-permeability reserves are poorly developed, resulting in a huge potential of remaining reserves in unproduced beach-bar sand reservoirs. For ultra-low permeability beach-bar sand reservoirs, water flooding development is greatly restricted (Li et al, 2020;Mahmud et al, 2020;Wang et al, 2020;Li., 2022;Wang et al, 2022). The development method that relies solely on elastic energy results in rapid decline in production and low recovery of crude oil.…”

Section: Introductionmentioning

confidence: 99%

Application of CO2 miscible flooding in ultra-low permeability beach-bar sand reservoir

Yang

Xu²,

Huang

et al. 2022

Front. Earth Sci.

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The beach-bar sand reservoir of the Sha 4 Member of the Shahejie Formation in the Dongying Sag is the main oil-bearing formation in this area. In recent years, its proven reserves have been getting lower and lower, and the poor petrophysical properties of the reservoir have made water injection development difficult. In turn, it results in a rapid decline in elastic development productivity and low oil recovery. In this study, the experimental evaluation and numerical simulation research on the adaptability of CO2 flooding in beach-bar sand reservoirs are carried out on the basis of fully investigating the successful examples of CO2 flooding conducted by the previous. According to the geological characteristics of the reservoir in the CL area of the Dongying Sag, the reasonable reservoir engineering parameters and surface injection procedures for the CO2 flooding have been formulated. Experiments show that after the completion of water flooding, the recovery factor of the CO2 continuous flooding is 85.64%. It proves that the recovery factor of the CO2 flooding is higher than that of the water flooding. Field tests have shown that CO2 molecules in beach-bar sand reservoirs behave in a supercritical state underground, which is easier to being injected into the reservoir than water. In addition, the displacement distance of the CO2 is obviously larger than that of the water injection development. The gas-oil ratio variation of different flooding types is different, and CO2 flooding can effectively increase the formation energy, and improve the oil recovery and economic benefits of this type of reservoir.

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Dynamic track model of miscible CO2 geological utilizations with complex microscopic pore-throat structures

Cited by 7 publications

References 34 publications

Characterization of CO2 miscible/immiscible flooding in low-permeability sandstones using NMR technology and VOF method

Characterization of CO2 miscible/immiscible flooding in low-permeability sandstones using NMR technology and VOF method

Research on the Timing of WAG Intervention in Low Permeability Reservoir CO2 Flooding Process to Improve CO2 Performance and Enhance Recovery

Application of CO2 miscible flooding in ultra-low permeability beach-bar sand reservoir

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