| Solubility and rheological behaviors of the saturated live crude oil were studied in detail in the paper, based on gas/liquid equilibrium theory, crude oil rheology theory and its measuring technique.(1)Using self-developed sampling device, pour point measuring device and rheology measuring device of gas-saturated crude oil, the gas-solubility and rheology of Chang10 gas-saturated crude oil were studied. The results show that the solubility of gas-saturated crude oil increases with increasing pressure; the dissolved gas in Chang10 crude oil is composed mainly by methane, ethane, propane and C4+; with the increase of pressure, the content of methane gradually increases while the contents of ethane, propane and C4+ slightly decrease. The pour point, abnormal point, viscosity/apparent viscosity and yield stress of Chang10 crude oil decrease obviously after gas dissolving, meaning the great improvemnet of the rheology at lower temperature. And modification effectiveness increases with increasing pressure. The C3 and C4+ components in the dissolved gas modify the crude oil rheology by dilution effect; the methane and ethane components in the dissolved gas modify the crude oil rheology by impeding the agglomeration of wax crystals.(2)Establishing the model of viscosity and solubility of live oil on the basis of the existing data, including the pure empirical model, the semi-theoretical and semi-empirical model based on the PR equation of state. We found that the difference between calculated values and experimental values is less, the error is about 15% which is in the scope of the project permission, and the model can be used for practical engineering.Through the above research work which had been done, the gas-dissolved property and rheological property were revealed, thus providing guideline methods for the application of modifying properties of the saturated live crude oil in oil field gathering and transportation line. |
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