Low-Salinity Surfactant Flooding—A Multimechanistic Enhanced-Oil-Recovery Method

Abstract

Summary We have applied UTCHEM-IPhreeqc to investigate low-salinity (LS) waterflooding and LS surfactant (LSS) flooding. Numerical-simulation results were compared with laboratory experiments reported by Alagic and Skauge (2010). UTCHEM-IPhreeqc combines the UTCHEM numerical chemical-flooding simulator with IPhreeqc, the United States Geological Survey geochemical model. The IPhreeqc model was coupled to UTCHEM to model LS waterflooding as a function of geochemical reactions. The surfactant coreflood experiments were performed in vertical cores without using polymer or other mobility-control agents. These experiments were performed at a velocity greater than the critical velocity for a gravity-stable flood. After history matching the experiments, additional numerical simulations of surfactant floods at the critical velocity were run to estimate the performance under stable conditions. We also simulated a surfactant flood at higher salinity with lower interfacial tension (IFT) and compared the results with the LSS flood. These results provide new insights into LS waterflooding and surfactant flooding. Addition of surfactants prevents the retrapping of oil that was initially mobilized using LS-brine injection. The results show that the proper selection of surfactant and the design of the surfactant flood might surpass the potential benefits of LS waterflooding in terms of both higher oil recovery and lower cost. Specially, a more-effective method is expected in a stable design with no preflood.

Effect of Monovalent and Divalent Salts on the Interfacial Tension of n-Heptane against Aqueous Anionic Surfactant Solutions

“…Generally, surfactants are categorized into four main groups: anionic, cationic, zwitterionic, and nonionic based on their charge of the hydrophilic group. Although a large amount of work has been carried out, ,− there is a lack of data for low salinity floods, which are a relatively new development. , …”

Hybrid EOR Methods Utilizing Low-Salinity Water

“…The stability of the displacement front in the LSW/LSS process is a critical issue to achieve a successful recovery. Tavassoli et al [50] showed that unstable fronts of surfactant floods due to the high velocity result in slow oil recovery. This problem can be solved through the combination of LSW with surfactant/polymer (SP).…”

“…The lack of modeling and optimization of the process through simulation studies is obvious in this field. In [50], Tavassoli et al applied UTCHEM-IPhreeqc to model LSW as a function of geochemical reactions and surfactant flooding. Their simulations were in good agreement with experiments carried out by [27].…”

Formulation of an Encapsulated Surfactant System, ESS, via β-CD Host–Guest Interactions to Inhibit Surfactant Adsorption onto Solid Surfaces

“…The loss of surfactant from the driving fluid during the flooding operation decreases the availability of surfactant for interactions with the oil phase, which hampers the reduction of the interfacial tension between the oil/water system and consequently the detachment and mobilization of residual oil. [1][2][3][6][7][8][9][10]12,14,19,20,23 In reality, it is impossible to fully inhibit surfactant losses onto reservoir rock during flooding operations; nevertheless, surfactant losses must be controlled to some extent because surfactants are expensive 21,24−27 and "the successful implementation of surfactant flooding EOR process depends mainly on the cost of surfactants" (Belhaj et al (2020) 1 ).…”