The foam reinforced with Janus amphiphilic graphene oxide to control steam channeling in heavy oil reservoir

Abstract

Foams have been considered effective diverters to decrease the mobility in the steam channel for heavy oil-recovery processes. Due to the high weight of chemical additive loss caused by adsorption to the rock surface and the poor thermal stability of these additives, the result of surfactant or polymer is usually unsatisfactory. To avoid these problems, nanoparticles can be utilized as novel assistants to enhance the generation and stabilization of foams. In this research, an amphiphilic graphene oxide (H-GO2), which is very effective at low concentrations, is utilized to enhance the foam performance in the process of plugging steam channeling. Compared with the foam prepared by using surfactant alone, the foam height and half-life at a low concentration (0.05 wt%) of H-GO2 in bulk medium increased by approximately 151% and 341%, respectively. The size distribution of bubbles in the presence of 0.05 wt% H-GO2 is uniform, and H-GO2 creates the gas-liquid interface film three times thicker than that of the surfactant without H-GO2. As NaCl concentration increased from 0.5 to 5 wt%, more foam was generated in a shorter time, and the half-life became longer. Excess NaCl causes less foam formation and a shorter half-life. Foam generation and stabilization are reduced with the CaCl2 concentration in solution increasing from 0 to 10 wt%, or the temperature increasing from 150 to 240 ℃. Corefloods with coinjected CO2 and water containing 0.05 wt% H-GO2 and surfactant can double the resistance factor of foam in the porous medium, compared with coinjection of CO2 and water containing only surfactant. The additional oil recovery of foam generated by surfactant alone is 14.6%. It is extraordinary that the increased recovery of 31.4% can be obtained by introducing only 0.05 wt% H-GO2 into the same foam. This work may provide a reference for steam channeling control in the steam injection development process of heavy oil oilfields.