Viscosifying proppants for use in carbon dioxide-based fracturing fluids and methods of making and use thereof

Abstract

Viscosifying proppants including proppant particles coated with a CO2-philic coating in which the CO2-philic coating has a solvable portion that viscosifies a CO2-based fluid when the viscosifying proppant is added to the CO2-based fluid are provided. Methods of making viscosifying proppants are also provided that include coating proppant particles with a precursor material of a CO2-philic material, and polymerizing the precursor material to form a viscosifying proppant. Viscous hydraulic fracturing fluids include a CO2-based fluid and the viscosifying proppants and methods of treating subterranean formations that include contacting a subterranean formation with a viscous hydraulic fracturing fluid and propagating at least one subterranean fracture are also provided.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority to U.S. Provisional Application Ser. No. 62 / 458,135, filed Feb. 13, 2017, which is incorporated by reference in its entirety.BACKGROUNDField[0002]Embodiments of the present disclosure generally relate to viscosifying proppant systems. Specifically, embodiments of the present disclosure relate to viscosifying proppants and methods of making the same, methods of using viscosifying proppants to produce viscous carbon dioxide-based hydraulic fracturing fluids, and methods of using the resulted viscous hydraulic fracturing fluid to treat subterranean formations.Technical Background[0003]Carbon dioxide (CO2) may be used in hydraulic fracturing fluids to provide non-aqueous alternatives to conventional water-based fluids, as some subterranean formations may be sensitive to water. Moreover, ‘water-less’ fluids are more environmentally sound, minimizing the depletion of natural-source freshwater ofte...

AI Technical Summary

Benefits of technology

The present patent discloses viscosifying proppants that can be used in hydraulic fracturing fluids. These proppants have a coating that is compatible with CO2 and can increase the viscosity of the fluid when added. This results in a more viscous hydraulic fracturing fluid that can be used to treat subterranean formations. Overall, this patent describes a way to improve the effectiveness and efficiency of hydraulic fracturing operations.

Problems solved by technology

However, conventional CO2-based fluids are not sufficiently viscous to suspend propping agents, such as “proppants,” that are added to fracturing fluids to hold open subterranean fractures during and following fracturing treatment.

Because of this reduced ability to suspend proppants, CO2-based fluids have not been widely considered for use in fracturing fluids.

Historically, it has been very difficult to thicken CO2-based fluids using additives, as CO2 is not a good solvent for high molecular-weight polymers.

Though water-based fluids may be easily viscosified owing to the many available thickening agents that readily dissolve in water, CO2-based fluids are not easily viscosified, owing to a lack of available materials that are CO2-soluble.

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