Flooding Effect Evaluation of Binary System with Ultra-low Interfacial Tension in the Class â…¢ Reservoir

Abstract

To explore the adaptability of betaine surfactant-polymer binary system with ultra-low interfacial tension in the class Ⅲ reservoir, By Berea cores, natural cores and the class Ⅲ reservoir oil sand packed tubular model, the basic binary system, screening emulsifier, high concentration of binary system and different slug size oil displacement experiments were carried out. The experimental results indicated that: The emulsification has a great influence on the recovery rate of the betaine surfactant-polymer binary system displacement. In Berea core, by changing the type of emulsifier to enhance emulsification effect, it can increase the binary flooding recovery rate by 7%; when the total mass concentration of betaine and EO emulsifier is increased from 0.3% to 0.35%, it can increase the binary flooding recovery rate by 5%; it is advisable when the betaine surfactant -EO emulsifier flooding slug is 0.7 PV; in the range of permeability of the class Ⅲ reservoir, the permeability and pore throat changes will not affect the recovery rate of binary flooding; in the Berea core, natural core and the class Ⅲ reservoir oil sand packed tubular model, which effective permeability is (88~227)×10-3μm2, (74～247)×10-3μm2 and 298×10-3μm2, the betaine surfactant-polymer binary flooding average recovery rate is 26.2%, 18.8% and 17.3%.