A Strategy for Low Cost, Effective Surfactant Injection

Abstract

Keywords: surfactant solubility phase behaviour microemulsion interfacial tension retention a b s t r a c t Ideally, in a chemical flooding process, one would like to inject a surfactant solution that has good solubility at the relevant conditions, ultralow interfacial tension (efficient oil mobilisation) and low loss of surfactant (better economics) in the porous medium. The key question is -can you have low loss of surfactant, i.e. low retention, at ultralow interfacial tension?To answer this question, we have undertaken a systematic study of surfactant solubility, phase behaviour, interfacial tension and retention as a function of salinity for a given surfactant formulation. The idea is to explore the interrelationship between these properties and find the best condition(s) for combined low interfacial tension and low retention in a surfactant flooding process.For the investigated surfactant formulation, ultra-low interfacial tensions ( o0.01 mN/m) can be found in the Winsor III region at optimal salinity. The aqueous solution at optimal salinity is, however, turbid, and retention values are high. On the other hand, for light oils, there are regions in the Winsor I area where (i) interfacial tensions are low (0.01 mN/m o IFT o0.1 mN/m), but not ultralow, (ii) aqueous solutions are clear and (iii) retention is 10 times lower than at optimal salinity. The search for an optimum surfactant formulation has to consider solution properties and retention in addition to the low interfacial tension. Based on our result, we therefore propose that Winsor I phase behaviour is the best option for a compromise between the properties in question.

Development and Evaluation of Surfactant Nanocapsules for Chemical Enhanced Oil Recovery (EOR) Applications

“…The researchers have focused their efforts on the development of new surfactant structures, selection of the concentration and/or chemical nature for being mixed with co-surfactants looking for ultralow IFT at different reservoir conditions (mineralogy, different quality of saltwater and crude oil, temperature, pressure, among others) and its impact on the oil recovery [ 9 ]. However, during the surfactant flooding, the rock surface adsorbs the chemical, limiting its extensive use due to the costs involved [ 10 ]. Hence, the reduction of the surfactant adsorption onto rock is a critical parameter in this type of cEOR operations.…”

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

“…These stabilisers alone could significantly affect effective fluid properties especially viscosity and interfacial tension 24,25 , thus having an EOR effect themselves.…”

Comparative studies of surfactant-enhanced-water, WAG and surfactant-enhanced-WAG injections in concurrent development of thin oil rim reservoir

“…Similarly, for the y and z directions, the value is calculated in an analogous manner to the transmissibility and depends on how the geometry was specified. Residual oil saturation in the pore space of reservoir rock can be de-saturated to half by simply increasing the capillary number to 1000 times by water flooding [21]- [23]. However, it is practically impossible to increase the capillary number to 1000 times by water flooding but with addition of low concentration surfactant; it is achievable [24].…”