Using fuzzy comprehensive evaluation model to screen CO 2huff and puff well candidates for enhanced oil recovery

To improve the success rate of CO2 enhanced recovery and development beneit of medium or low permeability smallcomplex fault block reservoirs, this paper develops an evaluation index system and grading evaluation criteria of well location screening for CO2 huff and puff. This is based on the integration of many case studies and theoretical analysis at home and abroad, luid proper- ties, reservoir characteristics and rock properties. On this basis, the paper then puts forward concrete method and steps for well location screening using fuzzy synthetic evaluation theory. With this procedure, the well locations are selected and reasonable injection and production rates for a speciic reservoir are assigned. Development practice reveals that introducing the fuzzy evaluation theory into CO2 huff and puff well location screening can greatly reduce operation risks and enhance oil recovery. The indings of this study are oftheoretical and technical signiicance for CO2 stimulation in similar reservoirs.