Branched Alkyl Alcohol Propoxylated Sulfate Surfactants for Improved Oil Recovery

Abstract

This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidates for chemcial enhanced oil recovery (EOR) applications. Results show that these anionic surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (IFT) at dilute concentrations, without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low IFT at high salinity, and hence may be suitable for use in more saline reservoirs. Adsorption tests onto kaolinite clay indicate that the loss of these surfactants can be comparable to or greater than other types of anionic surfactants. Surfactant performance was evaluated in oil recovery core flood tests. Selected formulations recovered 35-50 % waterflood residual oil even with dilute 0.2 wt% surfactant concentrations from Berea sandstone cores.

Screening of amphoteric and anionic surfactants for cEOR applications using a novel approach

“…It may be due to the fact that the maximum investigated salinity is 57,643 mg/L, and it is expected that further increase in salinity will increase the IFT after attaining a minimum. A similar observation was reported for Alfoterra 3n and 2n surfactant series [26] where up to 8% NaCl concentration only a decrease in the IFT was observed.…”

“…At low concentration of salts, most surfactants dissolve in aqueous phase while at high salinity surfactant stay in oleic phase. However, at optimal salinity the surfactant equally dissolves in oil and aqueous phase and gives the least IFT [26,34,37,38]. For the investigated system, only a decrease in the IFT with salinity was observed.…”

“…Capillary number is a dimensionless group directly related to oil recovery and defined as the ratio of viscous forces to interfacial forces acting on the oil drop. A decrease in IFT from 20 to 10 −2 mN/m can increase the capillary number to three orders of magnitude [25,26].…”

Controlled Hydrophobe Branching to Match Surfactant to Crude Oil Composition for Chemical EOR

“…It has been shown that mixed, branched surfactant structures can dispense with the need for co-solvent 4,7 . Several papers have reported that branched alcohol propoxy sulfates are very effective at forming microemulsions and achieving ultra-low IFTs with several crudes 8-10 and a recent paper reported acceptable oil recoveries in core floods even with low surfactant concentrations 11 .…”

Evaluation of a surfactant carrier for the effective propagation and target release of surfactants within porous media during enhanced oil recovery. Part I: Dynamic adsorption study

“…As stated by Pope 53 (2011), the primary goal of adding surfactants to the injection 54 water is to lower the interfacial tension (IFT) to ultra-low values 55 (%0.001 mN/m), at which essentially all of the oil trapped by 56 capillary forces can be displaced [1]. Ultra-low IFT takes place 57 when the interactions between surfactant, oil, and water reach 58 an exact equilibrium of affinities, condition at which, the capillary 81 rock surfaces has been studied by several researchers [14,[17][18][19][20][21][22]. 82 The formation of noncovalent host-guest inclusion complexes 83 with b-CD is well-known and the complexation between b-CD 84 and various types of guests (i.e.…”