The isothermal gelling process of thixotropic waxy crude oil was studied by using a combination of a rheological method and theoretical derivation. A model was established by using a structure parameter method, which has been proved to fit well with the experimental data of four different waxy crude oils; and by taking Qinghai waxy crude oil for example, the properties of isothermal gelling process were analyzed by both experimental data and correlation coefficient of the fitting curves. The results show that the increase of temperature, pre-shear rate and pre-shear time all can result in the weaker structure of waxy crude oil. And the changing rate of structure parameter (dλ/dt) increases with increasing the test temperature and pre-shear time; while the higher the pre-shear rate is, the higher the initial dλ/dt is and the smaller the final dλ/dt is, but the dλ/dt values for the waxy crude oils with pre-shear are all higher than those of the oil without pre-shear all the time.

Key words: waxy crude oil, isothermal gelling process, structure parameter, thixotropy, model