Abstract
Foam-assisted steam flooding is a promising technique to alleviate gas channeling and enhance sweep efficiency in heterogeneous heavy-oil reservoirs. However, long-term foam stabilization remains problematic at high temperatures. Three-phase foam (TPF), containing dispersed solid particles, has been proposed to improve foam stability under harsh reservoir conditions. We fabricated a novel TPF system by adding ultrafine fly ash particles, as well as high-temperature resistant microspheres with an adhesive coating layer. This work aims at assessing the ability of the generated TPF in controlling steam channeling and enhancing oil recovery. Static and core flood tests were performed to evaluate foam strength and stability. Our results suggested a stronger foamability at a lower consolidation agent concentration, while a longer half-life period of foam and settling time of solid particles at a larger consolidation agent concentration were observed. Bubbles suspended independently in the liquid phase, with sizes varying from 10 to 100 μm, smaller than that of the conventional foam, suggesting a significant enhancement of foam dispersity and stability. The plugging rate was close to 90% when the temperature was as high as 300 °C, demonstrating a well-accepted plugging effect under high temperatures. A larger pore volume injection of TPF yielded a higher EOR in parallel cores, which substantiated the effectiveness of the three-phase foam system in sealing high-permeability channels.
Highlights
Steam injection has been acknowledged as one of the most effective approaches for heavy-oil exploitation [1,2,3]
We present a novel fly ash three-phase foam system assisted by high-temperature resistant microspheres coated with an adhesive layer
This novel foam system allows mitigating gas channeling that occurs during steam injection into heterogeneous heavy-oil reservoirs
Summary
Steam injection has been acknowledged as one of the most effective approaches for heavy-oil exploitation [1,2,3]. Steam channeling emerges in heterogeneous reservoirs [8]. Foam, marked by low density, small filtration loss and strong particle-carrying ability, preferentially enter high-permeability regions, block large pores or channels, and reduce the permeability of high-permeable layers [9,10,11]. Foam has been widely used to assist steam flooding in heavy-oil exploitation, enabling us to decrease vapor mobility, enlarge the swept volume and enhance oil recovery [12,13]. Long-term foam stabilization remains challenging at high temperatures [14,15], concerning the effectiveness of profile control treatment by foam when injecting steam into heavy-oil reservoirs
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
