Water flooding is a conventional process of enhancing the extraction of hydrocarbon materials (e.g., crude oil, natural gas, etc.) from subterranean formations. In this process, an aqueous fluid (e.g., water, brine, etc.) is injected into the subterranean formation through injection wells to sweep a hydrocarbon material contained within interstitial spaces (e.g., pores, cracks, fractures, channels, etc.) of the subterranean formation toward production wells. One or more additives may be added to the aqueous fluid to assist in the extraction and subsequent processing of the hydrocarbon material.
For example, in some approaches, a surfactant and/or solid particles are added to the aqueous fluid. The surfactant and/or the solid particles can adhere to or gather at interfaces between a hydrocarbon material and an aqueous material to form a stabilized emulsion of one of the hydrocarbon material and the aqueous material dispersed in the other of the hydrocarbon material and the aqueous material. Stabilization by the surfactant and/or the solid particles lowers the energy of the system, preventing the dispersed material (e.g., the hydrocarbon material, or the aqueous material) from coalescing, and maintaining the one material dispersed as units (e.g., droplets) throughout the other material. In turn, the hydrocarbon material may be more easily transported through and extracted from the subterranean formation as compared to water flooding processes that do not employ the addition of a surfactant and/or solid particles.
Disadvantageously, however, the affectivity of various surfactants can be detrimentally reduced by the presence of dissolved salts (e.g., such as various salts typically present within a subterranean formation). In addition, surfactants can have a tendency to adhere to surfaces of the subterranean formation, requiring the economically undesirable addition of more surfactant to the injected aqueous fluid to account for such losses. Furthermore, solid particles can be difficult to remove from the stabilized emulsion during subsequent processing, preventing the hydrocarbon material and the aqueous material thereof from coalescing into distinct, immiscible components, and greatly inhibiting the separate collection of the hydrocarbon material.
It would, therefore, be desirable to have an improved method of extracting a hydrocarbon material from a subterranean formation to overcome one or more of the above problems.
USPTO Backgrounds
USPTO Backgrounds