How to Attain an Ultralow Interfacial Tension and a Three‐Phase Behavior with a Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 2. Performance Improvement Trends from Winsor's Premise to Currently Proposed Inter‐ and Intra‐Molecular Mixtures

Abstract

The minimum interfacial tension occurrence along a formulation scan at the so-called optimum formulation is discussed to be related to the interfacial curvature. The attained minimum tension is inversely proportional to the domain size of the bicontinuous microemulsion and to the interfacial layer rigidity, but no accurate prediction is available. The data from a very simple ternary system made of pure products accurately follows the correlation for optimum formulation, and exhibit a linear relationship between the performance index as the logarithm of the minimum tension at optimum, and the formulation variables. This relation is probably too simple when the number of variables is increased as in practical cases. The review of published data for more realistic systems proposed for enhanced oil recovery over the past 30 years indicates a general guidelines following Winsor’s basic studies concerning the surfactant–oil–water interfacial interactions. It is well known that the major performance benefits are achieved by blending amphiphilic species at the interface as intermolecular or intramolecular mixtures, sometimes in extremely complex formulations. The complexity is such that a good knowledge of the possible trends and an experienced practical know-how to avoid trial and error are important for the practitioner in enhanced oil recovery.

Ethylation of Di‐rhamnolipids: A Green Route to Produce Novel Sugar Fatty Acid Nonionic Surfactants

“…A relevant example of this equivalent is a n-alcohol ethoxylate with nine EO groups and 24 carbon atoms in the tail. Note that the C24 tail is known (observed in earlier studies [63,64] and reviewed recently [65]) to be roughly equivalent to a branched hydrophobe of two alkyl tails with ten carbon atoms each, which is the dominant structure of the hydrophobic moiety of ethyl di-rhamnolipids. Such an ethoxylated n-alcohol has a HLB of 7.3 according to Davies [41], which is smaller than the HLB of 8.7 calculated for the ethyl dirhamnolipids.…”

Petroleum sulfonates preparation and evaluation for chemical enhanced oil recovery in Colombian oil fields

“…When using blends of Petrostep ® S2 and our sulfonates, with crude-oil as the organic phase, Winsor III systems were not found. Thus, several commercial surfactants were tested, among them the Petrostep ® S13D, and an alkyl propoxy sulfate surfactant (C16-18PO13SO 4 ) (Gregersen et al, 2013;Wu et al, 2005;Carmona, Schechter, Wade & Weerasooriya, 1985) that showed good synergy with the petroleum sulfonates, probably due to inter and intramolecular extension of the interphase (Salager et al, 2013). In order to determine the surfactant mixing ratio performing the maximum solubilization of oil and water, sulfonate 4 was randomly selected and evaluated with Lisama-161 in different sulfonate to Petrostep ® S13D ratios (Figure 4).…”

Complexation of Surfactant/β‐Cyclodextrin to Inhibit Surfactant Adsorption onto Sand, Kaolin, and Shale for Applications in Enhanced Oil Recovery Processes. Part I: Static Adsorption Analysis

“…On a pore scale, surfactants reduce the interfacial tension between oil and water to ultralow values, which decreases capillary forces and releases oil from the rock into the driving fluid. Therefore, under the condition of a high capillary number, oil droplets can be efficiently mobilized [1][2][3].…”