Spontaneous imbibition (SI) during the extended shut-in period effectively enhances the production performance of shale gas wells. This study presents an experimental work to evaluate the relationship between SI and microscopic pore structures and assess the dynamics of fluid distributions during imbibition for Longmaxi shale. We conducted imbibition tests on six samples collected from the Longmaxi Shale in Southern Sichuan Basin. Also, we conducted a series of experiments on these six samples to characterize microscopic pore-structure parameters. Correlation analysis indicates that porosity, reservoir quality index, permeability, and average pore radius are among the key pore-structure parameters impacting imbibition recovery of our shale samples. In this study, we also conducted nuclear magnetic resonance (NMR) tests to investigate the dynamics of water distribution during imbibition. The NMR results indicate that the micropores and microfractures in the samples are filled with water earlier compared with macropores and macrofractures. The findings may thus provide new insights into the SI after fracturing operations in shales.
This study aims to develop a fractal model for the dynamic imbibition (DI) process in tight porous media. We developed the model by coupling the dynamic contact angle (DCA) into the DI model at capillary and core scales. A numerical method was proposed to solve the developed model. We then validated the model against experimental data reported in the literature. The results show a relatively satisfying fitting between our DI model and experimental data. We also compared the imbibition rate and oil recovery predicted by the DI model considering and not considering the DCA. The results indicate that considering the DCA improves the DI model's accuracy, whereas neglecting the DCA results in the overestimated imbibition rate and oil recovery for the DI process. We conducted sensitivity analysis to evaluate how the contact angle, interfacial tension, and displacement pressure affect our DI model's performance in calculating imbibition recovery. The results show a relatively more significant difference in imbibition recovery determined by DI models considering and not considering the DCA at a relatively high contact angle, a relatively high interfacial tension, and a relatively low displacing pressure. This study highlights the importance of considering the DCA in DI modeling for fracturing practices which associate with surfactant injections to alter wettability and reduce interfacial tension in tight reservoirs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.