Exploratory Research On Techniques Of Using CO₂ To Supercritical Deliver Heavy Oil

Generally speaking, it is very difficult to transport heavy oil because of its great viscosity and poor mobility. There are several methods that can be used to transport heavy oil, but all of them have some limitations. Supercritical CO₂ and heavy oil are strongly miscible. CO₂ that has dissolved in heavy oil can reduce the interactions between oil molecules and damage the internal network structure of heavy oil, so the viscosity of heavy oil can be significally reduced after the dissolution of CO₂. It has important significance to use supercritical CO₂ to reduce the viscosity of heavy oil and then to relize the transportation of heavy oil. This is a new heavy oil transportation technology.In this paper, the nature of supercritical CO₂ and heavy oil were studied. CO₂'s solubility in heavy oil and the properties of reducing the the viscosity of heavy oil with CO₂ were studied by expertimental means and software. The results showed that the viscosity of heavy oil decreased dramatically after the dissolution of CO₂. In this experiment, the best result appeared when the temperature is 60℃and the pressure is 14 MPa. The simulation results of software are close to those of the experiment, and the error is small. So the results of simulation have some reference values. Meanwhile, this paper studied the domestic and foreign research results to determine the appropriate calculational formulas that can be used to calculate the solubility of CO₂, the volume factors and the viscosity of heavy oil saturated with CO₂.In addition, the process of using supercritical CO₂ to tansport the heavy oil for a long-distance was simulated by using software. Through the simulaiton, this paper gives the boundary conditions of using supercritical CO₂ to transport heavy oil. Finally, the relevant economic analysis was carried out, which has certain forward-looking significance.