Study on the influence of emulsification ability of oil displacement system on its chemical flooding recovery

Abstract

Abstract In this paper, in order to study the effect of emulsification on the oil displacement of the system, several polymer, surfactant/polymer (S/P) and alkali/surfactant/polymer (A/S/P) systems were prepared for experiments. Firstly, the interfacial tension of each system was investigated. After the emulsion was prepared, the droplet size was observed by microscope and the intensity of the backscattered light during the destabilisation process of the emulsion was tested with the stability analyser. The TSI value was calculated to evaluate the stability of the emulsion. Finally, the Berea core displacement experiment (chemicals are used to displace oil from the core) was carried out to test the ability to enhance the oil recovery. The experimental results show that the emulsion formed by the A/S/P system with the simulation oil has the best stability. The chemical displacement recovery is the highest, which is 32.15 %. The emulsion stability of the S/P system is second, and the chemical displacement recoveries are 17.03 % and 20.76 %, respectively. The polymer system has no interfacial activity, does not form an emulsion, and has the lowest chemical displacement recovery of 8.02 %. This shows that the deeper the degree of emulsification of the system and the more stable the emulsion, the better the oil displacement effect of the oil displacement system.