Enhanced aqueous fluid saturation with gases in wellbores

Background

Resource extraction, carbon storage, and enhanced oil recovery increasingly demand advanced methods for achieving high levels of gas saturation in fluids under subsurface conditions, yet current techniques struggle with efficient and precise control. Traditional approaches often rely on co-injection methods that mix gases and liquids at the surface, resulting in unpredictable two-phase flow behavior and limited modulation of flow rates and pressures under downhole conditions.

This lack of independent control complicates the optimization of fluid mixing, especially in heterogeneous formations where injectivity varies markedly, leading to suboptimal gas dispersion and energy inefficiencies. In addition, methods based on porous media for nanobubble generation frequently face challenges with clogging and inconsistent bubble quality, thereby hindering their practical application in high-pressure environments.

Technology overview

A downhole system utilizes separate injection lines for aqueous and gaseous fluids that are mixed using gas spargers at a predetermined depth (150-2000m) to achieve enhanced gas saturation under in-situ hydrostatic pressure. Independent control over the flow rates and pressures of the fluids is main­tained throughout their respective tubing systems, optimizing mixing even in heterogeneous subsurface formations. Gas compressors, water pumps, and pressure and rate control devices work in tandem with optional flow restrictors—which can create a Bernoulli suction effect—to reduce surface energy requirements and improve mixing efficiency.

This design addresses challenges of co-injection by ensuring more predictable two-phase flow and greater supersaturation levels, while remaining adaptable to various industrial applications.

Benefits

• Improved process control: Independent control of aqueous and gaseous flow rates and pressures allows precise in-wellbore mixing, outperforming the co-injection methods used by Moleaer and Nano Gas Technology that suffer from limited regulation of two-phase flow regimes.
• Enhanced downhole efficiency: By leveraging in-situ hydrostatic pressure and facilitating downhole mixing, the invention achieves higher and more consistent gas saturation levels than surface-based gas generation methods, thereby optimizing conditions for resource extraction and storage applications.
• Energy reduction advantage: The optional incorporation of flow restrictors to induce Bernoulli's suction effect can lower the energy required for gas compression, offering a cost-effective alternative to conventional high-energy gas injection systems.
• Operational flexibility in heterogeneous formations: The design's independent control enables dynamic adjustment to varying subsurface injectivity, making it robust in heterogeneous wellbore conditions compared to traditional fixed co-injection approaches.
• Scalable and versatile application: The technology’s broad applicability—from enhanced oil recovery to carbon sequestration and energy storage—expands its market potential beyond methods focused solely on nanobubble generation.

Applications

• Enhanced oil recovery: The invention's ability to independently control and optimize downhole mixing of gases and aqueous fluids makes it ideally suited for improving oil extraction efficiency in heterogeneous reservoirs.
• Carbon capture and sequestration: Its precise in-situ gas saturation capability enables effective injection and long-term storage of CO₂ in subsurface formations, addressing industrial carbon management challenges.
• Subsurface energy storage and extraction: The technology supports controlled injection of energy carriers like hydrogen or methane, facilitating their storage and efficient retrieval from underground formations.