Conventional (steam injection) and unconventional (electrical/electromagnetic heating) heavy oil/bitumen recovery methods require a high amount of energy. The efficiency of these methods can be increased by improving the energy transfer to the oil for viscosity reduction. It has recently been shown that micron-sized metal particles improve the efficiency of some ex-situ processes such as coal liquefaction and pyrolysis, heavy oil upgrading, oil shale recovery, and heavy oil viscosity reduction. This idea, with some modifications, can be applied to reduce the energy input of the aforementioned recovery methods for more economical heavy oil/bitumen production. The major contribution of the metal particles is expected to improve viscosity reduction by reducing the amount of the required energy. The objective of this work is to clarify the mechanics of additional viscosity reduction using nano-size metals during thermal applications through a series of experiments.
In the absence of electromagnetic fields, exothermic chemical reactions and thermal conductivity enhancement are the two important functions of metals to cause a reduction of oil viscosity. Two sets of experiments were conducted to investigate these mechanisms. Different metal types including iron, nickel and copper with different sizes and their different compounds were selected. The viscosity of oil samples, mixed with these particles, was measured. The tests were repeated at different temperatures. Also, the effect of the metal particles on heat transfer enhancement was examined. Nano-sized particles were found to have a remarkable effect on heat transfer through heavy oil.
The experiments provided a good understanding of the ongoing mechanisms that would lead to a viscosity reduction by the addition of metal particles. The concentration, type, and size of the particles were found to be highly critical on viscosity reduction. The optimal values of these parameters were identified. The results and observations are expected to be useful in further studies and applications as to the efficiency improvement of the thermal applications for heavy-oil/bitumen recovery.