Enhancing coal seam gas recovery through greenzyme-induced relative permeability optimisation: Helium-driven core flooding experiments and field-scale production simulations
Wen Xi , Kunning Tang , Ying Da Wang , Yu Jing , Joan Esterle , Klaus Regenauer-Lieb , Lucas Evangelista , Ryan T. Armstrong , Peyman Mostaghimi
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引用次数: 0
Abstract
Coal seam gas (CSG) is an unconventional gas resource in the global energy supply. A key factor in predicting and evaluating methane production in coalbeds is coal relative permeability. This study explores the effects of an enzyme-based surfactant, GreenZyme (GZ), on coal relative permeability through drainage unsteady-state core flooding experiments. Initial measurements of interfacial tension (IFT) between helium and GZ solutions at various concentrations demonstrate a decrease in IFT from approximately 70 to 45 as GZ concentration increases, with 1.2 wt% identified as the critical concentration for solution preparation. Helium was employed as a substitute for methane to eliminate sorption effects and focus on liquid–gas phase interactions. The relative permeability curves for gas and water were derived using the Johnson–Bossler–Naumann (JBN) method. The results show that GZ improves the displacement of water by approximately 5%, with relative permeability curves for both water and gas moving leftward and upward in the presence of GZ. This enhancement is attributed to the reduction in IFT between the water and gas phases. To assess the impact at the field scale, an Eclipse-developed CSG production model incorporating experimental data was developed. Simulation results show that while the gas production rate based on the original relative permeability curves is initially higher during the first 0.28 years, the rate for the GZ-enhanced case surpasses it for the remainder of the production period. These findings provide valuable insights into the influence of GZ on coal relative permeability and demonstrate its potential to enhance CSG recovery at the field scale.
期刊介绍:
The International Journal of Coal Geology deals with fundamental and applied aspects of the geology and petrology of coal, oil/gas source rocks and shale gas resources. The journal aims to advance the exploration, exploitation and utilization of these resources, and to stimulate environmental awareness as well as advancement of engineering for effective resource management.