Research on Surfactant Flooding in High-temperature and High-salinity Reservoir for Enhanced Oil Recovery

Abstract The aim of this work was to research the solution properties of a new surfactant flooding system for high temperature and high salinity reservoir, which include trimeric sulfonate surfactants 1,2,3-tri(2-oxypropyl sulfonation-3-alkylether-propoxyl) propanes (TTSS-n) and anion-nonionic surfactant NPSO [sodium nonyl phenol polyethyleneoxy ether sulfonate, (EO = 10)]. The critical micelle concentrations (CMCs) of five trimeric sulfonate surfactants were smaller than 400 mg L−1. Furthermore, their interfacial tensions (IFTs) could reach an ultralow value with Tazhong 4 oil at lower concentrations. Through optimized formulation, we found that TTSS-12 had better properties and was selected as the major component of the surfactant flooding system. We designed an optimal formulation of the surfactant flooding system with 1 000 mg · L−1 TTSS-12 and 1 000 mg · L−1 NPSO surfactant. The system with a very small surfactant concentration could reach ultralow IFT with Tazhong 4 crude oils at high temperature (1...