Experimental Study On Flue Gas Assisted Steam Stimulation In Low Permeability Reservoirs

In the development of low permeability reservoir, due to its special geological conditionsand reservoir properties,leading to the existing mining technology is difficult to developefficient. Flue gas assisted steam stimulation technique is an effective method to improve therecovery of low permeability reservoir. As in the process of steam stimulation, water vaporformed hot water in the formation pressure, leading to a limited heating radius of water vapor,while the low thermal conductivity of N2in the flue gas, mixed with flue gas when steam huffand puff, the capacity of carrying heat of steam can be improved, increase the swept volumeof steam, with the increase of steam stimulation rounds, formations produce deficit, while N2can replenish formation energy because of greater compressibility. CO2in flue gas has largesolubility in crude oil, in the formation conditions,formed miscible and immiscible with theformation oil, further enhance oil recovery.To formation crude oil PVT analysis, temperature is300℃,injected into the flue gas is80%, oil viscosity decreased99.38%, saturation pressure is29.26MPa, gas-oil ratio reached107.39m3/m3, volume factor is1.4, the density is0.648g/cm3.Through the formation of oil PVT analysis of the results, o determine the flue gasassisted steam stimulation of flooding mechanism is viscosity reducing, expansiveeffect,dissolved gas drive effect, increased formation permeability,irreducible increases watersaturation, reduce the interfacial tension and bring the heat effect.Based on the characteristics of low permeability reservoirs and the gas injectiondevelopment at domestic and foreign present situation of low permeability reservoir on thebasis of the investigation, under the condition of simulated formation, through the experimentmethod,for non-homogeneous low permeability tube natural core huff and puff experimentsconducted five cycles, comparative analysis of its cumulative oil recovery, oil recovery cycle,gas-oil ratio,moisture content into the ability of the results, optimization of optimalparameters injection in the flue gas assisted steam huff and puff:water vapor ratio is12.78:87.22, injection temperature is300℃, injection pressure was27MPa, injection volumeis2.33cm3, soak time is8.8min, choke pressure of7MPa and huff and puff three cyclesappropriate.