油气水三相流体高温高压流变特性实验

Experiment of high-temperature and high-pressure rheological characteristics of oil-gas-water fluid

以大庆外输含蜡原油为实验介质,利用自行研制的高压流变特性测试系统,测试了实验油样在氮气和天然气两种气质加压条件下,油气两相和油气水三相在不同剪切速率、含水率及压力下的粘温特性,探讨了氮气和天然气的溶解度对含蜡原油析蜡点和溶蜡点的影响。结果表明:在氮气和天然气两种气质加压条件下,油气两相和油气水三相混合物的视粘度均随剪切速率的增大而减小,且温度越低剪切稀释性越明显。在相同的压力条件下,原油含水率低于20%时,油样视粘度随着含水率的增大而增大。在低于泡点压力的条件下,当以天然气加压时,油气水三相和油气两相混合物的溶蜡点和析蜡点均随压力升高而降低,而以氮气加压时的变化规律与此相反,说明天然气溶解于原油有利于改善原油的流动性。

Taking the Daqing waxy crude oil as an experimental media and adopting self-made high-pressure rheological characteristics test system,viscosity-temperature characteristics of oil-gas phase and oil-gas-water phase under different shear rates,water content ratios and pressures are tested when the experimental oil samples are under pressurization by nitrogen and natural gas,and the influences of nitrogen and gas solubility on WAP and WDT of the waxy oil are discussed.Results indicate that under pressurization by nitrogen and natural gas,apparent viscosities of oil-water mixtures and oil-gas-water mixtures are both reduced with the increase of shear rate,and shear thinning effects are more obvious when the temperature is lower.Under the same pressure conditions,the apparent viscosity of oil samples increases with the increase of water content ratios when the l water cut of crude oi is lower than 20%.Under the condition of being lower than bubble point pressure,WDT and WAP of oil-gas-water mixtures and oil-gas mixtures decrease with the increase of pressure when natural gas is used for pressurization,and the change law is on the contrary when the nitrogen is used for pressurization,and it is indicated that the natural gas dissolving in the crude oil is in favor of improving flow of crude oil.