Interfacial rheology of a novel dispersed particle gel soft heterogeneous combination flooding system at the oil-water interface

The interfacial phenomena reflected by the thickness of oil films and the stability of oil-in-water emulsions were observed in the soft heterogeneous combination (SHC) flooding process, which were closely linked with the oil recovery. In this work, the effects of tetradecyl hydroxyl sulfo betaine (THSB) concentration and dispersed particle gel (DPG) concentration on the interfacial rheology were investigated; the adsorption performance at different temperatures, salinities and aging times were also systematically evaluated to determine the impact of external factors. The results show that three interactions appeared between the surfactant molecules and DPG particles. The adsorption process presents four stages. At a low THSB concentration and low DPG concentration, some DPG particles can adsorb on the interface together with the surfactant molecules, which markedly increase the adsorption film strength. When the THSB concentration increases, the surfactant molecules tend to interact with each other and aggregates of the surfactant molecules with DPG particles also appear, thereby damaging the compact film structure. As DPG particles are continuously added, the aggregates between particles enhance the strength of the adsorption film. Additionally, interfacial properties were maintained at high-temperatures, high-salinities and long aging times, which indicates the promising application of the SHC flooding system in reservoirs.