A Mathematical Model Study On Heavy Oil Well Stimulated By Nonwireline Electromagnetic Heating

Nonwireline electromagnetic heating in a single heavy oil well is a new technology, which is a combination of electrical heating tube technology and electromagnetic heating technology. Focused on the difficulty of heavy oil flowing into the well-bore, the electromagnetic heating warms up the reservoir stratum near the well-bore, making it easier for the oil to flow.; however, the tubing heating technology can heat and reduce the viscosity of oil in the well-bore, which improves the liability of the technology and the utilization rate of the energy, as well as decrease the construction cost and difficulty. In the paper, a concrete introduction on the principle of the technology is presented, the well-bore structure and equipments is expatiated, the power frequency and voltage is studied. The mathematical model of the nonwireline electromagnetic heating is systematically studied; Based on law of conservation of matter and law of conservation of energy, mathematical model of oil-water two-phase radial flow at one-dimensional in porous media is established; Mathematical model of tubing heating and model of injecting fluid assistant electromagnetic heating are analyzed and established. Equations of models are discretize and numerical calculated; Based on the Delphi programming language, the corresponding computer software is developed to dynamically predict and evaluate the efficiency of this electromagnetic heating process. Then the test well in the field is taken as an example. Make a theoretical dynamic prediction of the formation temperature and pressure and the temperature profile in the well-bore; The factors that influence the heating result are analysied, such as the power, oil yield and so on. The result shows that: (1)The electromagnetic heating can warms up the reservoir stratum near the well-bore effectively. The heating distance can reach more than 2m in a short time and it will get longer as time passes, which, though, is not obvious. Thus it is adaptive to heat the well while it is producing. (2)At a constant oil yield, as the heating time increase, the temperature profile and the temperature of the oil flowing into the well-bore is tending to be constant and the relevant time is 330 hours on heating production. (3)The tube heating can have an affection on the oil in the well, which is influenced by the flow rate and heating power. (4)The combination of injecting fluid and electromagnetic heating can increase the heating radius.(5)The effect of electromagnetic heating can be dominated by the geological factors such as the porosity, water saturation, besides controllable factors such as heating power, flow rate. The theoretical analysis and the simulation research give theoretical guidance for field application.