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September 22, 2008

Improved process for getting oil from Oil Shale



Oil Recovery from Oil Shales by Electrical Heating has been improved by adding iron powder. (Canada -University of Alberta and Turkey researchers The economics of the process are presented above.

The recovery characteristics of four different oil shale samples were tested experimentally using the retort technique. To accomplish efficient temperature distribution, the thermal conductivity of the oil shale samples was increased by the addition of three different iron powders. The doses of iron powders were optimized for each oil shale sample based on the highest oil production value experimentally. The experiments were then modeled using the electrical heating option of a commercial reservoir simulator. The viscosity−temperature relationship was obtained by matching the experimentally obtained temperature distribution in the cores and production data to the numerical ones. After the other parameters needed for the numerical model were collected and compiled, field-scale simulations were performed and a parametric analysis was performed for different oil shale cases. The experimental and numerical results show that field-scale oil recovery from oil shales by electrical heating could be technically and economically viable.









The best result was obtained for the OS4 case with iron powder. Over the time period of investigation (90 days), the increasing trend was still obvious and the plateau region had not been reached unlike the other seven cases. It is interesting that its “raw version” also showed a similar trend but much less oil production. Note that OS4 has significantly higher rock heat capacity compared to the other three samples.

(1) Viscosity−temperature relationship as data to the simulator was observed as the most critical parameter, but it is not easily measurable. Therefore, an experimental study was performed to obtain this input data by numerically simulating the experiments and matching the history for temperature distribution and production. (2) After 400 °C, the relationship between viscosity and temperature was observed as linear on a semi-log plot. This is the pyrolysis temperature. (3) Introducing iron powder into the reservoir for practical applications is a critical issue, but we are not aware of any application or suggestion in the literature in this regard. The addition of iron powder could be achieved by injecting iron powders into the reservoir, after mixing them with petroleum-based fluids, such as light oils or solvents. If the field is shallow enough for surface mining, a better solution would be adding the iron powders during the extraction process. (4) The technical and economic feasibility analyses showed that electrical heating is still a marginal application, but the results proved that it is in an applicable range. (5) All oil shales showed different recovery trends. The production rate and the ultimate recovery from the oil shale case of OS4 were remarkably higher compared to the other three cases. This could be attributed to significantly higher rock heat capacity of this particular sample compared to the other three samples.


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