Gas recycling optimization in gas condensate reservoirs using three dimensional compositional modeling

Mohamed R. Kasem, Reservoir Department, PetroNefertiti Oil Company, P.O.Box: 1303, Cairo, EgyptFollow
Hamid M. Khattab, Department of Petroleum Engineering, Faculty of Petroleum and Mining Engineering, Suez University, P.O.Box: 43221, Suez, Egypt
Ali M. Wahba, Department of Petroleum Engineering, Faculty of Petroleum and Mining Engineering, Suez University, P.O.Box: 43221, Suez, Egypt

Article Type

Research Paper

Abstract

Gas condensate reservoirs have unique production challenges due to condensate dropout in reservoir pores when the pressure drops below the dew point. This immobile condensate accumulation reduces the well productivity. Many technologies were applied to improve the recovery of condensate in gas reservoirs. Dry gas (98% methane and 2% ethane) recycling is a famous enhanced production methodology to maximize condensate recovery. The gas and condensate recovery factors in a gas condensate reservoir under gas injection mechanism are influenced by many factors the difference between the reservoir pressure and the dew point pressure, the condensate content, the reservoir quality (porosity & permeability), and producing well geometry. The main issue in developing gas condensate reservoir under dry gas recycling is to optimize the gas injection ratio under the above-mentioned factors. This research provides sensitivity study results for the optimum dry gas injection ratios across a wide range of reservoir qualities and gas condensate contents to maximize condensate and gas recovery. The study employs a three-dimensional compositional model to maximize condensate recovery by varying the gas-recycling ratio in reservoirs of different qualities and gas with varying condensate contents. The analysis considers both vertical and horizontal producing well configurations. The injection starts early at initial reservoir pressure above the dew point pressure. Initially, a depletion scenario was modeled with five vertical producing wells under natural depletion as the base case. Then, dry gas recycling was applied with recycling ratios ranging from 0 to 0.9, achieved by converting one producer into an injector in a crestal injection pattern. Horizontal production wells instead of vertical producing wells were also used to evaluate the impact of well geometry on recovery performance. The results indicate that the optimum dry gas injection ratio increases with higher gas condensate contents reservoir. As the optimal dry gas injection ratio rises from 50% for gas with condensate content of 20 STB/MMSCF to 75% for gas with condensate content of 40 & 60 STB/MMSCF. Additionally, reservoir quality and well geometry significantly influence performance. For high-quality reservoirs, horizontal producing wells are better than vertical producing wells for high condensate content gas reservoirs. While for low-quality reservoirs: Vertical producing wells are more effective than horizontal wells for high-condensate-content gas reservoirs. These results can be used as guidelines for optimum dry gas injection ratios to maximize gas and condensate recovery for gas condensate reservoir with properties under the range of reservoir qualities and gas condensate contents covered in the study. Especially if there isn’t enough data or in the early production stage of the gas condensate reservoir to build robust models .

Keywords

Gas production; condensate recovery; gas recycling; optimization; 3D compositional modeling; gas condensate reservoir

Recommended Citation

Kasem, Mohamed R.; Khattab, Hamid M.; and Wahba, Ali M. (2025) "Gas recycling optimization in gas condensate reservoirs using three dimensional compositional modeling," Egyptian Journal of Petroleum: Vol. 34 : Iss. 3 , Article 3.
Available at: https://doi.org/10.62593/2090-2468.1072