Laboratory investigation of cyclic gas injection using CO2/N2 mixture to enhance heavy oil recovery in a pressure-depleted reservoir

Using starch graft copolymer gel to assist the CO2huff-n-puff process for enhanced oil recovery in a water channeling reservoir

“…22,23 Nitrogen (N 2 ) is also used to assist with CO 2 injection due to its strong ability of pressure maintenance, however, its applications are limited in coal bed methane or pressure depleted oil reservoirs. 24,25 Foaming agents are reported to be helpful reagents to control water and gas mobilities in heterogeneous reservoirs, which can be used to assist with the CO 2 -EOR process, however, its application is still limited under serious channeling conditions due to the weak stability of the foam. [26][27][28] Because gel usually has a higher blocking strength compared to foam, it is more suitable to treat large-scale channels.…”

Molecular Insights into Asphaltene Aggregation in Gas Flooding

“…The heavy oil with high viscosity is hard to spontaneously flow, and various tertiary oil recovery technologies have been well developed for heavy oil recovery. Among these technologies, the injecting gas method is of superb performance thanks to its high miscible displacement efficiency. − Gases like CO 2 , N 2 , and CH 4 were generally adopted as injecting gases for enhanced oil recovery (EOR). ,,− The injected CO 2 can not only increase the oil saturation beyond the residual saturation, but also reduce the viscosity, thereby endowing the heavy oil additional fluidity . Generally, the injecting gas is supercritical fluid under the reservoir conditions with high pressure and temperature, and have excellent dissolubility to crude oil and extraordinary diffusivity.…”