MD-CFD simulation on the miscible displacement process of hydrocarbon gas flooding under deep reservoir conditions

Laboratory Experiments of Hydrocarbon Gas Flooding and Its Influencing Factors on Oil Recovery in a Low Permeability Reservoir with Medium Viscous Oil

“…Gas can penetrate reservoir rocks more quickly, resulting in gas channeling occurring earlier . Finally, as the gas injection rate increases, the reason why the gas displacement pressure difference increases is that the rapid advance of the leading edge of the gas will form a steep pressure gradient . This pressure gradient can more effectively push gas through the reservoir, thereby increasing the displacement pressure difference between the gas and crude oil.…”

“…Second, the increase of back pressure will lead to the increase of total pressure in the reservoir, thus reducing the pressure gradient in the underground reservoir. A smaller pressure gradient means that the driving force of hydrocarbon gas in the reservoir displacement is small, so the movement speed of gas will slow down, which makes the gas channeling time become longer . Finally, high back pressure will increase the gas displacement pressure difference, because high back pressure makes it easier for the liquid hydrocarbon molecules in the crude oil to remain stable, reducing the formation of bubbles in the liquid crude oil, which will reduce the relative fluidity of the crude oil, making it easier for the gas to push in the liquid crude oil, thus increasing the displacement pressure difference …”

Molecular Insights into Soaking in Hybrid N2–CO2 Huff-n-Puff: A Case Study of a Single Quartz Nanopore-Hydrocarbon System

“…Although these prior studies have shed light on microscopic CO 2 /N 2 -EOR mechanisms, there is still limited research available on the microscopic migration and interaction mechanism of fluids (injected gas and shale oil) during the soaking step of hybrid N 2 −CO 2 HnP operations. In particular, existing knowledge often relies on the dead-end pore 34 (a nanochannel open at one end and closed at the other) connected to a reservoir microfracture or macropore, which rarely considers both counter-current and cocurrent displacements occurring in through-pores pore 38 (nanochannels open at both ends) during the soaking process. Thus, the simulated results of the soaking model composed of the dead-end pore may not precisely match the actual HnP/soaking situation.…”