Experimental investigation and modelling of CO₂‐foam flow in heavy oil systems

Abstract

In this work, the C14‐16 alpha olefin sulphonate (AOS) surfactant, octylphenol ethoxylate (TX‐100), and methyl bis[Ethyl(Tallowate)]‐2‐hydroxyethyl ammonium methyl sulphate (VT‐90) surfactant were selected as representatives of anionic, nonionic, and cationic surfactant to stabilize foam. The effects of surfactant concentration and gas/liquid injection rates on foam performance were examined by performing a series of oil‐free foam flow tests by injecting CO2 and a foaming surfactant simultaneously into sandpacks. Foam flooding was conducted as a tertiary enhanced oil recovery (EOR) method after conventional water flooding and surfactant flooding. Furthermore, a new method was proposed to determine the residual oil saturation. The foam stability in the presence and absence of heavy oil was studied by a comparative evaluation of the mobility reduction factor (FMR) in both cases. The foam fractional flow modelling by Dholkawala and Sarma[36] was modified based on experimental results obtained in this study. The range of the ratio of two important model parameters (Cg/Cc) at various foam qualities was determined and could be used for large‐scale predictions. The results showed that during the oil‐free foam displacement experiments higher foam apparent viscosities (italicμitalicapp) were attained at lower gas flow rates and the maximum was attained at a total gas and liquid injection rate of 0.25 cm3/min with a gas fractional flow ratio of 0.8 for the foam in the absence of oil. The presence of oil reduced the foam mobility reduction factors (FMR) to different degrees with FMR‐without oil / FMR‐with oil ranging from 4.25–13.69, indicating that the oil had a detrimental effect on the foam texture. The foam flooding successfully produced an additional 8.1–21.52 % of OOIP, which can be attributed to the combined effect of increasing the pressure gradient and oil transporting mechanisms.

Comprehensive Review on the Role of Surfactants in the Chemical Enhanced Oil Recovery Process

“…The injection of foam also increases the lateral pressure gradient which helps to tackle gravity segregation problems. 120 Foam is generated due to drainage of liquid between two adjacent air bubbles, with their shapes deformed. There exists a capillary force in the plateau region between the bubble boundaries which drains the liquid out of the lamellae (Figure 19a).…”

“…A thin liquid film known as lamellae separates the gas bubbles and the aqueous phase. A wide variety of gases like carbon dioxide, nitrogen, and natural gases can be used to generate foam. , Gas injection for the EOR application faces two major challenges: formation heterogeneities and contrasting viscous profiles of gas as compared to in situ reservoir fluids. Foam addresses these drawbacks and has emerged as one of the most promising EOR techniques.…”

“…This allows fluids to be injected into less permeable layers for better recovery of trapped oil. The injection of foam also increases the lateral pressure gradient which helps to tackle gravity segregation problems …”

Data-driven prediction of in situ CO2 foam strength for enhanced oil recovery and carbon sequestration

“…† For the study of porous media, 145 data points were collected from nine different published works. [17][18][19][20][43][44][45][46][47] In all experiments, the AOS surfactant stabilized CO 2 foam in sandstone reservoirs. The parameters considered for the ML model are summarized in Table 3, while additional details are provided in Table S2.…”

Investigation of the Effect of Nanoparticle-Stabilized Foam on EOR: Nitrogen Foam and Methane Foam

“…Although air foam is convenient, due to its high oxygen content, it often causes corrosion of the downhole tubular strings. For CO 2 foam flooding, its oil displacement effect in oilfields is good, but because of the scarcity and cost of CO 2 gas sources in certain areas, its application has been restricted. − The distribution of natural gas in China is uneven, and there are abundant natural gas sources in certain oil reservoirs in the west. When natural gas is dissolved in crude oil, the viscosity of the crude oil decreases.…”