| In the use of pipe-flow- loop experimental device, it is systematically researched on the attenuation characteristics of pressure transmission in gelled crude oil pipeline startup process and the compression characteristics of gelled crude oil, which provide a certain practical value for solving problems faced in restart process of hot waxy crude pipeline. Two following parts are mainly included in this paper: the variation law of pressure amplitude value and pressure transmission velocity during constant-pressure startup process in loop device, the solution of low-pressure compression coefficient of gelled crude oil in specific state based on dichotomy method.Using waxy crude oil In Sudan as a sample of the experiment, several restart tests under constant pressure of gelled crude oil are carried out in different experimental conditions to analysis the variation of the pressure amplitude and transmission speed of the pressure during the restart process in different ring road test devices. The following conclusions are found in the tests : â‘ the transmission speed of starting pressure in gelled crude oil is not constant, and it decreases gradually with the extension of the distance it passes, which is different from the transmission regulation of the restart pressure in Newtonian fluid. â‘¡the concept that the starting pressure amplitude decay rate is defined, and the experiments find that the starting pressure amplitude decay rate and the transmission distance are in the approximate linear relationship. When starting pressure transmission distance is determined, the ratio of the decay of starting pressure in the transfer process and that applied in the first end is a fixed value. To analysis these phenomena, it is believed that the viscoelastroplasticity and compressibility that are peculiar properties of the gel ed crude oil are main factors.Take use of low pressure compression factor fp to characterize the initial compression characteristics of gelled crude oil. The startup process of gelled crude oil under constant pressure was simulated by compiling program, and the low compression factor of gelled crude oil at different experimental conditions was calculated.The results showed that the low-pressure compressibility coefficient of gelled crude oil has a great difference with the compressibility coefficient of Newtonian crude oil, and is several times bigger than it. The following conclusions have been found after analyzing the low-pressure compressibility coefficient of gelled crude oil calculated under different experimental conditions: â‘ the low-pressure compressibility coefficient of gelled crude oil is a parameter that characterizes the compressible property of gel structure formed in certain conditions, which has no relationship with imposed start-up conditions. â‘¡ when the other experimental conditions are identical, the lower the startup temperature is, the bigger the low-pressure compressibility coefficient of gelled crude oil; â‘¢ as the static cooling increases, the low-pressure compressibility coefficient of gelled crude oil increases. Finally, the causes of these characteristics are analyzed and summarized in paper. |
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