CT Scan Study of Immiscible Foam Flow in Porous Media for Enhancing Oil Recovery

Abstract

A systematic CT-scan-aided laboratory study of N2 foam in Bentheimer sandstone cores is reported. The aim of the study was to investigate whether foam can improve oil recovery from clastic reservoirs subject to immiscible gas flooding. Foam was generated in situ in water-flooded sandstone cores by coinjecting gas and surfactant solution at fixed foam quality. It was stabilized using two surfactants, namely, C14–16 α-olefin sulfonate (AOS) and mixtures of AOS and a polymeric fluorocarbon (FC) ester. The effects of surfactant concentration, injection direction, surfactant preflush, and core length on foam behavior were examined in detail. Stable foams were obtained in the presence of waterflood residual oil. It was found that foam strength (mobility reduction factor) increases with surfactant concentration. Foam development and, correspondingly, oil recovery without surfactant preflush were delayed compared to the case with preflush. Gravity-stable foam injection caused a rapid increase in foam strength and an incremental oil recovery almost twice that for unstable flow conditions. Core floods revealed that the incremental oil recovery by foam was as much as (23 ± 2)% of the oil initially in place after injection of 4.0 pore volumes (PV) of foam (equal to the injection of 0.36 PV of surfactant solution). Incremental oil recovery was only (5.0 ± 0.5)% for gas flooding under the same injection conditions. It appears that oil production by foam flooding occurs by the following main mechanisms: (1) residual oil saturation to foam flooding is lower than that to water flooding; (2) formation of an oil bank in the first few injected pore volumes, coinciding with a large increase of capillary number; and (3) a long tail production due to the transport of tiny oil droplets within the flowing foam at a fairly constant capillary number. The observations of this study support the concept that foam is potentially an efficient enhanced oil recovery (EOR) method.

High‐Speed Quantification of Pore‐Scale Multiphase Flow of Water and Supercritical CO2 in 2‐D Heterogeneous Porous Micromodels: Flow Regimes and Interface Dynamics

“…Multiphase flow in porous media exists across innumerable natural and engineering systems, and it plays a defining role in a broad spectrum of applications in the energy and environmental sectors, including enhanced oil recovery (Simjoo et al, 2013), ground water remediation (Dawson & Roberts, 1997), fuel cells (Bazylak, 2009), and carbon capture and storage (CCS; Huppert & Neufeld, 2014). Over the past two decades, geological sequestration of CO 2 in saline aquifers as well as depleted oil and gas reservoirs has attracted significant research attention, as it is widely considered a promising solution for the containment of greenhouse gas effects (Bachu, 2000;Gunter et al, 1997;Koide et al, 1992;Pacala & Socolow, 2004).…”

Review of surfactant-assisted chemical enhanced oil recovery for carbonate reservoirs: challenges and future perspectives

“…Due to technical difficulties, chemical-based EOR methods have never been very popular for significantly enhanced oil production from carbonate reservoirs. Nevertheless, surfactant-based cEOR technologies have been implemented as chemical well stimulators, wettability altering agents, microemulsion, and foam-generating agents consistently Simjoo et al 2013;Wang and Mohanty 2013). Currently, this is an area of intense research (Ahmadi and Shadizadeh 2012;Bera et al 2012;Zendehboudi et al 2013;Bourbiaux et al 2014;Santvoort and Golombok 2015).…”

Simulation of Instabilities and Fingering in Surfactant Alternating Gas (SAG) Foam Enhanced Oil Recovery

“…Foam has been suggested for a long time to improve the above-mentioned problems with gas injection (Falls et al, 1985Wellington and Vinegar, 1988;Hirasaki and Lawson, 1988;Hirasaki, 1989;Rossen, 1996;Simjoo et al, 2013;Andrianov et al, 2012) . The aim is to control the gas mobility by creating lamellae (foam films) along the gas flow paths in the porous medium.…”