Using microwave to produce heavy oil reservoirs: Experimental and numerical study

Date

2015-12

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Abstract

This PhD dissertation presents a new technique to produce heavy oil reservoirs. This new technique may be applied to produce heavy oil reservoirs where it is difficult or insufficient to apply any of the conventional techniques. The new technique involves the use of microwave, activated carbon, and aluminum oxide. Experimental and numerical results show that this technique may significantly increase the productivity of heavy oil reservoirs. Thermal recovery is the major technique to produce heavy crude oil. Heavy oil reservoirs are heated up and as a result the oil viscosity is reduced. Consequently, it would be easier to produce oil. Currently, the major thermal recovery techniques are steam-assisted-gravity-drainage (SAGD), hot fluid injection, or in-situ combustion. In the new technique, hydraulic fracture(s) are created in heavy oil reservoirs and filled with activated carbon. Microwave antenna(s) would be placed inside the producers or in other wells close to them. Activated carbon has significantly higher real and imaginary permittivity values than any naturally existing materials in heavy oil reservoirs, namely water, oil, and rock. Real permittivity indicates how much of the applied microwaves is absorbed by the exposed material. On the other hand, imaginary permittivity indicates the ability of the material to convert this absorbed energy into heat. As a result, activated carbon will heat up to very high temperatures when microwave irradiation is directed at it and hence it will heat up the reservoir. Numerical simulation showed that the use of activated carbon may increase the oil recovery factor between 5 and 14% when compared to the use of microwave only. Experimental results showed that activated carbon may reach a temperature of more than 800˚F in a short period of time when exposed to microwave irradiation. The time needed for water to heat up to around 200˚F is 4 times the time needed to heat the same volume of activated carbon. Also, experimental results showed that the time needed to heat activated carbon may be reduced if it is preheated by any mean then heated using microwave. Aluminum oxide may be used to overcome the very high temperature due to the use of activated carbon. This very high temperature may affect the integrity of the well completion adjacent to the microwave antenna. The presence of aluminum oxide in the hydraulic fracture sections (as a tail-in proppant) close to the wellbore will help in lowering the temperature close to the wellbore. Aluminum oxide was selected because it has a very low imaginary permittivity. Experimental results showed that aluminum oxide has significantly lower tendency to heat up than activated carbon or water when exposed to microwave irradiation. The new technique may be combined with fluid injection techniques to increase the recovery factor of heavy oil reservoirs. Furthermore, following certain patterns in the way wells are operated or placed may result in a further increase of the heavy oil recovered from the reservoir.

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Keywords

Heavy oil, Microwave, Activated carbon, Thermal recovery

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