Abstract
The inflection point temperature of rheology (IPTR) of heavy oil transforming from a non-Newtonian fluid into a Newtonian fluid is a key parameter in the steam huff- and-puff process. It is particularly relevant in terms of optimizing injection parameters, calculating the heating radius, and determining well spaces. However, the current approach exhibits obvious shortcomings, such as the randomness of the selected tangent line and inadaptability for extra-heavy oil with high viscosity. Therefore, this paper presents a novel method for calculating IPTR using viscosity–temperature data. The approach is based on the Arrhenius equation and quantitatively evaluates the IPTR according to the inflection point of the apparent activation energy. The IPTR values of four heavy-oil samples obtained from the Bohai Oilfield in China were quantitatively predicted according to viscosity–temperature data using the proposed method. The method's accuracy was verified by a series of rheological investigations on samples obtained from two heavy-oil wells. Additionally, the new method was used to predict IPTR according to the published viscosity–temperature data of 10 heavy-oil samples from the Shengli Oilfield. Again, a good correspondence was found, and mean absolute and relative errors of 3°C and 4.6%, respectively, were reported. Therefore, the proposed model was confirmed to improve the prediction accuracy of the existing method, and provided a new method for calculating the IPTR of heavy-oil.
Effect of Charging and Discharging Process of PCM with Paraffin and Al2O3 Additive Subjected to Three Point Temperature Locations
