Comparative Evaluation of Electrical Heating Methods for Oil Sand Reservoirs




此外,目前还无法在单一模型中模拟这三种电加热过程,本论文的工作使得可以直接对这些不同的方法进行比较。通过两种情况来检验电加热在油砂油藏中的可行性:a) 包含加热源的水平井,b) 在两口水平井中都有加热源。比较了三种电加热过程中的温度、水饱和度和电耗的模拟结果。


For thermal heavy oil recovery, conventional steam injection processes are generally limited to reservoirs of relatively shallow depth, high permeability, thick pay zones and homogeneity. An alternative approach of applying electrical energy, including methods of electric heater, electrical resistance heating and electromagnetic heating, can be used to generate heat in reservoirs that are not suitable for steam injection or to improve the economics of the heavy oil recovery compared with steam injection processes. However, in the current, the most widely used simulation method of electrical heating is the data coupling of two simulators, one is used for calculation of electrical heating and the other is used for calculation of a oil reservoir. The work in this thesis provides a single simulator that is capable of modelling all electrical heating processes for heavy oil and oil sands thermal recovery and the computational overhead and complexity of swapping data back and forth between two simulators has been omitted.

In this work, a new numerical simulator is developed that handles the three electrical heating processes, such as electric heater, electrical resistance heating and electromagnetic heating. New models regarding the physical processes of the electrical heating methods have been derived and used for numerical simulation. The electric current balance was used for the modelling of electrical current flow in oil sands reservoirs with an appropriate treatment of electrical conductivity between neighbouring grids. A Helmholtz equation for the magnetic field by deformation of Maxwell’s equations is presented that makes it feasible to find electromagnetic field solutions for an inhomogeneous medium, such as a oil reservoir.

Also, it has not been possible until now to model all three electrical heating processes in a single model and the work in this thesis enables a direct comparison of the different methods to be made. The feasibility of electrical heating in oil sands reservoirs is examined in two case categories: a) a horizontal well containing a heating source and b) a horizontal well-pair with heating sources located in both wells. Simulation results are compared in temperature, water saturation and electrical energy dissipation in the three electrical heating processes.