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A novel process has been developed to produce highly concentrated forms of surfactants suitable for chemical Enhanced Oil Recovery (cEOR) in the form of powders. Powders are advantageous for cEOR applications because, through their lower water content (typically 3%), they have the potential to reduce transportation costs and simplify the logistics of transporting surfactants from the production location to field locations. Data are presented showing the properties and advantages of powder cEOR surfactants and how they compare to the more conventional liquid form of surfactants. The manufacturing route first involves the preparation of higher active matter liquids (around 70% active) that are subsequently converted into powders using dedicated, standard mixing equipment, the same type used for the manufacture of laundry powders. In this work, several surfactant powders were produced on a pilot plant scale using a number of internal olefin sulfonates to establish applicability for different cEOR projects. The blended powders are agglomerates of surfactant and sodium carbonate and were made both with and without polymer (termed ASP and AS powders respectively). The AS and ASP powders were found to easily dissolve in brine, eliminating the need for special field equipment for dissolution, and gave faster polymer dissolution in water compared with dissolving the polymer as a separate component. The powders have acceptable physical properties that facilitate transport and dispersion in brine and have been tested at desired ratios of surfactant to alkali. This paper also outlines how higher active matter liquids can be manufactured to avoid gel phases, improve their handleability and lower their viscosity. The surfactant powder approach has the potential to substantially reduce costs for full scale chemical EOR projects where large chemical volumes are manufactured, transported, stored and injected.

In this paper an innovative structure/property approach is used to evaluate several commercially available surfactants in tests relevant to both alkaline-surfactant-polymer (ASP) and surfactant-polymer (SP) floods, in order to gain an understanding of how hydrophobe structure is related to surfactant performance and crude oil composition. The surfactant structural elements considered here include relative branching level and carbon chain length. This has application to chemical EOR implementation in fields over a range of reservoir temperatures and salinity. Phase behavior (giving interfacial tension), and micro-emulsion viscosity tests were carried out for internal olefin sulfonates and mixtures with alcohol propoxy sulfates to identify those that perform well while minimizing or eliminating the use of costly co-solvents. Hydrophobe branching and carbon chain length, characterized by gas chromatography, were used to match surfactants to certain crude oil properties such as natural surfactants, including total acid number (TAN) and asphaltenes, and the ratio of saturates/aromatics. The paper also examines how crude oil sampling influences crude properties and surfactant performance. The approach used and associated data contribute to cost reduction of formulations through a) better matching of commercially produced surfactants to the reservoir and crude oil properties to improve oil recovery efficiency, and b) minimizing or eliminating the use of co-solvents to reduce formulation and logistics costs. In addition, the study demonstrates how binary blends from a few core surfactants can match formulations across regionally different crude oils thereby simplifying formulation selection, and reducing uncertainty and cost.