Characteristics of gas-oil contact and mobilization limit during gas-assisted gravity drainage process
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Abstract
Gravity can reduce the instability of the gas-oil contact that is caused by gas channeling in locations with low flow resistance, such as high-permeability layers, macropores, and fractures during the gas-assisted gravity drainage process. Herein, the microscopic forces during the gas-assisted gravity drainage process were analyzed and combined with the capillary model to study the occurrence boundary of gas-assisted gravity drainage process, and the characteristics of the gas-oil contact in the gas-assisted gravity drainage process was discussed. The results show that free gravity drainage occurs only in pores where a certain height of the oil column and pore radius are reached. Furthermore, the lower the oil-gas interface migration rate, the easier free gravity drainage occurs. In other scenarios, additional gas injection is required. During the gas-assisted gravity drainage process, the gas-oil contact moves down stably as a transition. The width of the transition zone and the available pore radius are related to the gas-oil contact migration rate and the oil viscosity; the smaller the gas-oil contact migration rate and the lower the oil viscosity, the smaller pore throat can be involved in mobilization. Optimizing the gas injection rate and reducing the oil viscosity can delay the gas channeling maturity time, which is beneficial for the realization of the gas-assisted gravity drainage process. Finally, a method considering micropore heterogeneity is established for determining the critical gas injection rate, while the mainstream pore throat can be involved in mobilization and the gas-oil contact can be stabilized at the same time. The method of determining the critical gas injection rate can help researchers and reservoir engineers to better understand and implement the gas-assisted gravity drainage process.
Cited as: Kong, D., Gao, J., Lian, P., Zheng, R, Zhu, W., Xu, Y. Characteristics of gas-oil contact and mobilization limit during gas-assisted gravity drainage process. Advances in Geo-Energy Research, 2022, 6(2): 169-176. https://doi.org/10.46690/ager.2022.02.08
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Al-Mudhafar, W. J., Rao, D., McCreery, E. Evaluation of immiscible CO2 enhance oil recovery through the CGI, WAG, and GAGD processes in south rumaila oil field. Paper We P2 06 Presented at 79th EAGE Conference and Exhibition, Paris, France, 12-15 June, 2017.
Chen, X., Li, Y., Liao, G., et al. Experimental investigation on stable displacement mechanism and oil recovery enhancement of oxygen-reduced air assisted gravity drainage. Petroleum Exploration and Development, 2020, 47(4): 836-845.
Colla, P. A new analytical method for the motion of a two-phase interface in a tilted porous medium. Paper SGP-TR-202 Presented at 39th Stanford Geothermal Workshop, Stanford University, Stanford, California, USA, 24-26 February, 2014.
Dake, L. P. Fundamentals of Reservoir Engineering. Amsterdam, Netherlands, Elsevier, 1978.
Dietz, D. A theoretical approach to the problem of encroaching and by-passing edge water. Proc, 1953, 56: 83-92.
Dumore, J. M. Stability considerations in downward miscible displacements. Society of Petroleum Engineers Journal, 1964, 4(4): 356-362.
Gao, W., Li, Y., Zhang, J., et al. Effect of surfactant on pore-scale mobilization characteristics in various pore structure conglomerate for enhanced oil recovery. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021, 627: 127150.
Grattoni, C. A., Jing, X. D., Dawe, R. A. Dimensionless groups for three-phase gravity drainage flow in porous media. Journal of Petroleum Science and Engineering, 2001, 29(1): 53-65.
Hagoort, J. Oil recovery by gravity drainage. Society of Petroleum Engineers Journal, 1980, 20(3): 139-150.
Hasanzadeh, M., Azin, R., Fatehi, R., et al. New insights into forced and free fall gravity drainage performance in a fractured physical model. Journal of Petroleum Science and Engineering, 2021, 203: 108568.
Khorshidian, H., James, L. A., Butt, S. D. Demonstrating the effect of hydraulic continuity of the wetting phase on the performance of pore network micromodels during gas assisted gravity drainage. Journal of Petroleum Science and Engineering, 2018, 165: 375-387.
Kong, D., Gao, Y., Sarma, H., et al. Experimental investigation of immiscible water-alternating-gas injection in ultra-high water-cut stage reservoir. Advances in Geo-Energy Research, 2021a, 5(2): 139-152.
Kong, D., Lian, P., Zheng, R., et al. Performance demonstration of gas-assisted gravity drainage in a heterogeneous reservoir using a 3D scaled model. RSC Advances, 2021b, 11(49): 30610-30622.
Kong, D., Lian, P., Zhu, W., et al. Pore-scale investigation of immiscible gas-assisted gravity drainage. Physics of Fluids, 2020, 32(12): 122004.
Kulkarni, M. M., Rao, D. N. Analytical modeling of the forced gravity drainage GAGD process. Paper 72361 Presented at AIChE Annual Meeting, San Francisco, CA, USA, 12-17 November, 2006.
Liu, Z., Yang, Y., Yao, J., et al. Pore-scale remaining oil distribution under different pore volume water injection based on CT technology. Advances in Geo-Energy Research, 2017, 1(3): 171-181.
Lv, B., Ma, Q., Cheng, H. Simulation research on CO2 and water flooding of long core test. Natural Gas and Oil, 2015, 33(2): 69-72. (in Chinese)
Mahmoud, T., Rao, D. N. Mechanisms and performance demonstration of the gas-assisted gravity-drainage process using visual models. Paper SPE 110132 Presented at SPE Annual Technical Conference and Exhibition, Anaheim, California, USA, 11-14 November, 2007.
Meszaros, G., Chakma, A., Jha, K., et al. Scaled model studies and numerical simulation of inert gas injection with horizontal wells. Paper SPE 20529 Presented at SPE Annual Technical Conference and Exhibition, New Orleans, LA, USA, 23-26 September, 1990.
Namba, T., Nakashima, T., Yonebayashi, H., et al. Force balance analysis and efficient measures to improve vertical sweep efficiency in oil-wet carbonate reservoirs. Paper SPE 193099 Presented at Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 12-15 November, 2018.
Outmans, H. D. Transient interfaces during immiscible liquid-liquid displacement in porous media. Society of Petroleum Engineers Journal, 1962, 2(2): 156-164.
Purcell, W. R. Capillary pressures—their measurement using mercury and the calculation of permeability therefrom. Journal of Petroleum Technology, 1949, 1(2): 39-48.
Raeini, A. Q., Blunt, M. J., Bijeljic, B. Direct simulations of two-phase flow on micro-CT images of porous media and upscaling of pore-scale forces. Advances in Water Resources, 2014, 74: 116-126.
Rahman, A., Happy, F. A., Ahmed, S., et al. Development of scaling criteria for enhanced oil recovery: A review. Journal of Petroleum Science and Engineering, 2017, 158: 66-79.
Rao, D., Ayirala, S., Kulkarni, M., et al. Development of gas assisted gravity drainage (GAGD) process for improved light oil recovery. Paper SPE 89357 Presented at SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Tulsa, Oklahoma, 17-21 April, 2004.
S. Hill, M. A., F. Inst. P., F. S. S. Channeling in packed columns. Chemical Engineering Science, 1952, 1(6): 247-253.
Sheldon, J. W., Fayers, F. J. The motion of an interface between two fluids in a slightly dipping porous medium. Society of Petroleum Engineers Journal, 1962, 2(3): 275-282.
Stephen, K. D., Pickup, G. E., Sorbie, K. S. The local analysis of changing force balances in immiscible incompressible two-phase flow. Transport in Porous Media, 2001, 45(1): 63-88.
Wall, G., Brown, R. The determination of pore-size distributions from sorption isotherms and mercury penetration in interconnected pores: The application of percolation theory. Journal of Colloid and Interface Science, 1981, 82(1): 141-149.
Wang, J., Ji, Z., Liu, H., et al. Experiments on nitrogen assisted gravity drainage in fractured-vuggy reservoirs. Petroleum Exploration and Development, 2019, 46(2): 355-366.
Yu, H., Wang, L., Zhou, D., et al. Experimental study on sweep characteristics of gas gravity drainage in the inter-layer oil reservoir. Frontiers in Energy Research, 2021, 9: 760315.
DOI: https://doi.org/10.46690/ager.2022.02.08
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