Experiment Research On Optimization Of Injection Parameters For Nitrogen Foam Flooding

Foam is a kind of disperse system that gas in liquid under the action of foaming agent.The apparent viscosity of foam is high in large pore path and flow resistance increases with the increase of the injection volum.When the value of foam flow resistance exceeds that in small pore path and foam enter into the low permeability small pore path increasingly.The apparent viscosity of foam is low and the stability of foam poor in small pore path.Therefore,the displacement of foam flooding is greatly improved.This paper studied the experiment research on optimization of injection parameters for nitrogen foam flooding in field text block.This paper is mainly consisted of three parts as described below.(1)Based on research results at home and abroad and summarized the basic properties of foam and concept,the foam formation mechanism in porous media,main influence factors of the foam stability in porous media.These work provided a theoretical basis for experiment research on optimization of injection parameters for nitrogen foam flooding and comparision of different types of reservoir and displacing mediums.(2)Designed and carried out nitrogen foam flooding experiments in target text block under reservoir pressure on the condition of different gas liquid ratio(1:2,1:1,2:1,3:1),different injection volume(0.2,0.3,0.4,0.5,0.6,0.7PV),different the concentration fo foam agent(0.2,0.3,0.4%)and stavilizing foam agent(0.04,0.08,0.12,0.16%),different injection method(mixed injection,alternative injection 0.1 PV,alternative injection 0.15 PV),different injection rate(0.5,1.0,1.5,2.0,2.5,3.0 mL/min).The results showed that the best gas liquid ratio is 1:1,the best injection volume is 0.6 PV,the best concentration of foam agent is 0.3% and stabilizing foam agent is 0.12% and the best injection method is mixed injection.(3)Designed and carried out nitrogen foam flooding contrast experimetns with different permeability cores(the permeability is 190,50,2 × 10-3?m2)and different displacing mediums(nitrogen,natural gas).The results showed that the gas natural foam flooding compared with nitrogen foam flooding is a slightly improve ultimate recovery efficiency.Natural gas foam flooding is larger than that of nitrogen foam flooding ultimate recovery efficiency increased by 1% when the permeability is 190×10-3?m2.The study of experiment arrangements and results on optimization of injection parameters for nitrogen foam flooding has important guiding significance on filed nitrogen foam flooding.