N-Solv Corp. is a technology development company with a mission to create and implement new technologies for extracting valuable hydrocarbon resources from the tar sands in Alberta and around the world. N-Solv’s proprietary extraction technology is based on solvent extraction techniques and plant designs that result in much lower greenhouse gas emissions, surface pollution, and energy demand while using no water and yielding a higher quality product.

Canada

United States

PCT

Method and Apparatus for Stimulating Heavy Oil Production
Canadian Patent 2,235,085
The company has obtained Canadian Patent 2,235,085 for a down hole tool for heating solvent adjacent to the oil producing zone. Essentially, the solvent is pumped down from the surface at ambient temperature, and passes through the heater, is heated and is then pumped into the formation. This tool allows for local heat delivery as may be needed in certain reservoir conditions, and for the rapid initial formation of an extraction chamber. This early patent application is included for completeness, but is not considered to be a central technology.
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Method and Apparatus for Stimulating Heavy Oil Production
Canadian Patent Application 2,299,790
This earlier patent application is directed to a method of enhanced oil recovery through use of a condensing solvent process and is closely related to patent 2,351,148. The solvent’s in situ pressure is controlled so that the dew point temperature of the solvent is above the naturally occurring formation temperature. As a result the solvent can be injected as a vapour into the formation and condense on the walls or extraction surface of an extraction chamber. The latent heat of condensation is given up to the extraction surface and the combination of the heat and the solvent dilution helps reduce the viscosity of the in situ hydrocarbons. Pressure control leads to temperature control, and control over mass flux (which influences the solvent-to-oil ratio).
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Method and Apparatus for Stimulating Heavy Oil Production
Canadian Patent Application 2,351,148
A key aspect of N-Solv’s technology is the removal of non-condensable gases from the extraction chamber. This aspect is covered by the claims of Canadian patent application 2,351,148. The claims of this allowed application are directed to inventions relating to controlling the extraction conditions to improve extraction rates. Non-condensables gases are substances other than the preferred solvent, which are present as vapours in the extraction chamber, and which are not condensable at the desired extraction conditions. The desired extraction conditions are those conditions which result in a preferential rate of heat and solvent delivery to the extraction interface through condensation of the vapour solvent in the chamber onto the bitumen extraction surface. By controlling the extraction chamber pressure, the condensation temperature of the solvent can also be controlled, permitting the solvent to be delivered at a predetermined temperature. The temperature, in turn, will determine the mass flow rates. Since naturally occurring non-condensable gases arise at the extraction interface as the bitumen is warmed and because non-condensable solvent impurities (which remain behind after the solvent condenses) are delivered to the interface by the solvent itself, the non-condensable gases accumulate in the worst possible position, namely, between the incoming solvent and the extraction interface. The greater the percentage of non-condensables present in such a barrier layer at the extraction interface, the lower the dew point temperature becomes until solvent condensation stops altogether at the interface. The barrier layer prevents the solvent from reaching the bitumen thereby preventing both heat transfer and solvent dilution.

The claims of patent application 2,351,148 cover managing the extraction conditions within the extraction chamber to ensure that such non-condensable substances do not accumulate in a way to block heat transfer at the extraction interface between the solvent and the bitumen to be extracted. One way this is accomplished is to maintain bubble point conditions at the extraction interface to permit continued solvent condensation at the extraction surface. An associated invention claimed in this application is the purification of the solvent, whether it is recovered from the produced hydrocarbons or being introduced from a solvent source above grade, to remove non-condensable impurities in the first place. This under-saturates the solvent in non-condensable species, making it possible for the solvent to absorb and remove such species from the extraction surface rather than to add them. The claims are also directed to the step of removing the non-condensables as a liquid from the chamber to permit the solvent continued access to the extraction interface. Claims are also directed to a plant having a solvent re-circulating system which removes less condensable compound impurities from the re-circulating solvent.
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Energy Efficient Method and Apparatus for Stimulating Heavy Oil Production
Canadian Patent Application 2,374,115
Canadian Patent Application 2,374,115 is directed to an energy efficient method and apparatus for stimulating heavy oil production. The company’s proprietary extraction technology is based on the understanding that a small temperature rise of only, for example, 40°C to 60°C is all that is required in most cases to reduce the bitumen viscosity enough to mobilize the bitumen. The energy demand for a process which seeks such a modest temperature rise is small enough that it requires significantly less energy to achieve extraction conditions in situ. This modest energy needed can be obtained from various sources, including a heat pump or even waste heat. The company’s technology can dovetail smoothly with an existing SAGD facility and can be powered entirely by the waste heat from a SAGD facility, for example. The claims of the application are directed to an extraction process which has waste heat as an energy source. An initial assessment by the examiner is that six separate inventions are claimed, and the company has responded by pursuing one of the inventions. Five divisional applications are thus possible from the base case.
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Method and Apparatus for Test Heavy Oil Production Processes
Canadian Patent Application 2,436,158
Canadian Patent Application 2,436,158 is directed to a method of testing and a test apparatus for solvent based heavy oil production processes. The company’s scientists were unsatisfied with the conventional experimental approaches to laboratory testing of in situ processes. These conventional systems rely on scaled equipment and scaling assumptions which are somewhat theoretical and, in the opinion of the company, questionable. Historically poor correlation exists between lab data and field data of identical processes. The failure of Vapex at DOVAP is one example of not being able to reproduce conventional lab results in the field.

To respond to these concerns, an unscaled experimental design was developed by the company in which real time measurements of extraction rates at in situ temperatures and pressures could be made. Laboratory setting was required, eliminating the distorting effects that boundary conditions can impose on temperature profiles, and the company developed proprietary experimental equipment and methods to achieve this unprecedented analytic capability.

The claimed invention is a bench top modelling unit and a method of testing which recreates a slice of the reservoir in which the boundary conditions that serve as a limitation on prior art devices are eliminated. The invention consists of thousands of tiny individually controlled heat tiles which surround a can containing bitumen impregnated sand. The individual tiles can be temperature controlled to provide a temperature profile at the lateral edges, top, and bottom of the can which matches the internal temperature conditions achieved by the in situ extraction process being tested. In this manner, an extraction interface that moves through the test bed can proceed without interference from boundary conditions at the edges of the can. It is the company’s opinion that realistic piloting of thermally based in situ recovery processes are impossible without addressing the concerns covered by this patent. A corresponding U.S. patent application also has been filed for this technology.
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Method and Apparatus for Stimulating Heavy Oil Production
Canadian Patent Application 2,567,399
This application is a divisional application from 2,235,085 and is directed to methods of introducing heat down hole to encourage solvent aided extraction processes. This application is intended to provide counterpart method protection to the apparatus protection covered in 2,235,085.
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An In Situ Extraction Process for the Recovery of Hydrocarbons
Canadian Patent Application 2,591,354
This patent application, similar to patent application 2,351,148, is directed to a novel group of solvents which are expected to be both low cost and effective in a solvent based gravity drainage process. The solvents consist substantially of one of the group of hydrogen sulphide (H₂S), ammonia (NH₃), or carbonyl suphide (COS). The patent covers the design, construction, and operation of extraction facilities and well as the process used to mobilize in situ hydrocarbons for extraction. Particularly the use of COS could provide an efficient method of sequestering a large amount of carbon as liquid COS has a higher capacity of carbon than gaseous carbon dioxide.
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Methods and Apparatuses for Enhanced In Situ Hydrocarbon Production
Canadian Patent Application 2,552,482
The company has a license for the tar sands for the use of Canadian Patent Application 2,552,482. This patent covers a process for recovering hydrocarbons in which the location of the non-condensable gases are managed within the extraction chamber and a separate flow path is provided to remove such non-condensable gases from the chamber. This invention is based on the concept that in some cases it is desirable to prevent heat transfer from the solvent to the surface of the extraction chamber. An example would be where the extraction chamber has grown to the top of the bitumen play and further upward condensation will uselessly heat the overburden. Another example is where the bitumen play is poorly confined and the non-condensable gases can be positioned to prevent a loss of confinement. The preferred location for accumulating the gases is near the top of the chamber where the accumulated gases act as barrier gases to help limit heat loss to the overburden and thereby provide chamber integrity and improved confinement. This application has 32 claims, 31 of which have been indicated as being novel, having inventive step and industrial applicability by a PCT Search report.
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Methods and Apparatuses for SAGD Hydrocarbon Production
Canadian Patent Application 2,549,614
This application improves the performance, specifically the energy efficiency of hydrocarbon production using a buoyancy modifying agent in SAGD.

The addition of heat in the form of steam to bitumen causes gases, such as methane, to be liberated from the bitumen. The methane tends to accumulate at the extraction interface inhibiting heat transfer and thus oil production. By adding an agent that modifies buoyancy, the methane will instead accumulate at the top of the reservoir where it doesn’t interfere with heat transfer and acts as an insulating blanket to prevent heat loss through the overburden. A vent placed in the top of the chamber will help control the thickness of the accumulated gas blanket.
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