Carbon dioxide (CO2)/water foams are of interest for mobility control in CO2 enhanced oil recovery (EOR) and as energized fracture fluids or as hybrid processes that combine aspects of both processes. It is challenging to stabilize ultradry foams with extremely high internal-phase gas fraction given the high capillary pressure and the rapid drainage rate of the lamellae between the gas bubbles. However, the authors demonstrate that these ultradry CO2-in-water foams may be stabilized with surfactants that form viscoelastic worm-like micelles in the aqueous phase.
Introduction
In this study, the authors extend the study of ultradry CO2/water foams composed of worm-like micelles to higher temperatures by adding an electrolyte, potassium chloride (KCl), and a cationic surfactant, decyldimethylamine (C10DMA), to the primary surfactant, sodium lauryl ether sulfate (SLES). The continuous-phase viscosity and surface shear viscosity of this formulation were found to be approximately two orders of magnitude higher when worm-like micelles were formed at room temperature. The foam morphology was measured at high pressure with microscopy, and a long lifetime of foam bubbles was demonstrated.
