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Combined Electromagnetic Heating and Solvent Injection for Heavy Oil Recovery
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- Author / Creator
- Hu, Lanxiao
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To meet the increasing energy demand, there is a growing interest in exploiting the unconventional hydrocarbon resources such as heavy oil, bitumen, and shale oil. Combined electromagnetic (EM) heating and solvent injection is recently proposed to enhance oil recovery. The EM heating, converting the electrical energy into heat, reduces carbon emission caused by steam generation, avoids excessive water usage, and holds great potential to recover heavy oil from reservoirs where steam-based methods are less effective. The solvent injection also plays an important role in this hybrid process, which further thins the heavy oil by dilution, reduces the residual oil saturation, forms a vapor chamber to facilitate the gravity drainage, and supplements the natural energy for oil production.The combined EM heating and solvent injection is a multi-physics process involving the propagation and absorption of electromagnetic waves, the frictional heat generated by the interactions of the polarized reservoir materials and electromagnetic waves, and the heat/mass transfer in porous media. We are currently at the initial stage of the study of this hybrid process. It is of great importance to measure the fundamental data, conduct experimental investigations, and develop mathematical models, for achieving better understanding, design, and optimization of this hybrid technique. In the dissertation, we first use an open-ended co-axial probe method to measure the permittivity of the constituents of oil sands, oil sands mixtures with different porosity and water saturation, n-hexane/bitumen mixtures, and n-hexane/oil sands mixtures; the permittivity data ranging from 200 MHz to 10GHz are obtained. Based on the experimental data obtained, the commonly used mixing models are evaluated in terms of their accuracies in predicting the permittivity of n-hexane/oil sands mixtures. Next, we build an experimental setup to investigate the essential recovery mechanisms and to evaluate the effects of major influential factors on the recovery performance of this hybrid process. A series of experiments including premixed experiments (the solvent is premixed with heavy oil in the sand pack) and dynamic flow experiments (the solvent is injected into the sand pack) are performed to examine the effects of EM heating power, solvent type, and water saturation on the recovery performance. We also explore different ways of combining the EM heating and solvent injection to achieve a better performance of this hybrid process. In addition, the compositions of the produced oil samples are characterized by saturates, aromatics, resins, and asphaltenes tests to examine the in-situ upgrading effect of EM heating.Then, we investigate the effect of EM heating on changing the petrophysical properties of formation rocks. Different formation rocks, including continental shale, Berea-sandstone, tight sandstone, and Indiana-carbonate, are exposed to EM heating for three minutes. Subsequently, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), N2 adsorption/desorption, and core flooding experiments are used to characterize the petrophysical properties changes of rock samples caused by EM heating. Oven-heating experiments are also conducted to distinguish the effects of EM heating and conductive heating. Lab-scale finite element simulations are performed to verify the experimental results and to further analyze the temperature and stress distribution of rock samples under EM heating.Lastly, we propose a semi-analytical model to simulate the oil recovery of the combined EM heating and solvent injection in SAGD-liked wells; the semi-analytical model is computationally efficient and preserves the essential mechanisms governing the hybrid process. The model consists of three major parts: estimation of the temperature distribution of EM heating, calculation of the solvent distribution, and evaluation of the oil flow rate based on the temperature and solvent distributions. The proposed model is validated against the experimental results. Finally, we use the proposed semi-analytical model to explore the dependence of recovery performance on the major process parameters, as well as determine the optimal process parameters that can yield the maximum economic benefits.
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- Graduation date
- Spring 2019
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.