Harcros has spent the last several years focusing on specialty surfactants for EOR applications. The typical Harcros EOR surfactant is capable of reducing interfacial tension at the surface of an oil droplet to ultra-low levels ( < 10-4 dynes/cm). This unique technology is the subject of several, global Harcros patents. The efficacy of these built-for-purpose surfactants stems from the presence of a large hydrophobe, relatively large blocks of ethylene oxide and propylene oxide [(EO)20-45(PO)20-45] and an electrolyte tolerant end-capping group. These Harcros surfactants may be used for both ASP and SP technologies.