Air-foam EOR Technology Indoor Experimental Study In Wen120Reservoir

As of January2013,a total of20development Wells in Wen120reservoir,thecumulative oil production is31.71×104t, the composite moisture content is92.04%,recoverable reserves of recovery degree is74.46%. Due to reservoir of hightemperature (87℃)and high salinity(28291mg/L), the conventional polymer flooding,table/poly binary compound flooding and alkaline/table/asp flooding,etc. Due to thetemperature resistance and salt resistance of the oil displacement system is poor, theeffects of flooding is worse.Air foam flooding was developed a technology of cheap and efficient to EOR inrecent years, the foam has high apparent viscosity and improve the displacementefficiency and sweep efficiency ideally under the condition of high temperature andhigh salt, and been widely attention.Therefore, carried out indoor experiments toenhance oil recovery by air foam flooding in Wen120reservoir. Including thescreening and evaluation of frother, research the seepage flow characteristic of thefoam system, the evaluation of oil displacement effect and the study of the dynamiccharacteristics. The results show that the foaming agent was XHY-4K, the effectiveconcentration was0.1%, the foam injection slug was0.30PV. The minimum foamingconcentration of frother XHY-4K was0.001%. Foam system with good temperatureresistance and salt resistance, The temperature of Wen120reservoir is87℃,formation water salinity of Wen120reservoir is28291mg/L, in200mL foamingliquid, foaming volume is660mL, half-life of foam is2326s, composite index offoam is153.62×104mL s. With the increasing of pressure, the stability of the foamsystem does enhancement. in200mL foaming liquid, foaming volume is1865mL,half-life of foam is3756s, composite index of foam is700.49×104mL s when thepressure is15MPa. Core flooding experiment results show that resistance coefficientwithin30~90, residual resistance coefficient is3.1, critical blistering speed is0.1m/dwhen the flow of foam system in porous media. Critical bubbly oil saturation is16%,when the oil saturation is more than30%, the resistance coefficient of foam system isabout25. When permeability ratio gradually increased, the increasing amplitude of EOR than water flooding is reduced after the first increased, the inflection point ofpermeability differential is8.9. When foam injected slug was0.30PV EOR than waterflooding is was17.24%OOIP. The timing of foaming agent and the peak time offoaming agent concentration in High permeability layer (tube) was earlier than lowpermeability layer (tube).The peak of frother concentration in High permeability layer(tube) was102mg/L,it is1.65times than the peak of frother concentration in lowpermeability layer (tube). Air foam flooding is feasible effective new methods andnew technologies of tertiary oil recovery in Wen120reservoir.