Abstract: The invention has to do with treatment of dilution centrifuging tailings ch are produced in connection with a hot water extraction operation for recovery of bitumen from oil sands. The tailings are subjected to induced gas flotation for a predetermined period of time to recover contained hydrocarbons as froth.

Abstract: It has been found that controlling the rate of withdrawal of tailings from a hot water process primary separation vessel with a rake torque sensor is attended by problems when the feed to the vessel is high in fine solids content. It was also found that a nuclear density gauge was much better at controlling the withdrawal with the high fines feed, but did not work as well as rake torque control with low fines feed. Therefore the withdrawal is now controlled with a rake torque sensor when the vessel is receiving low fines feed and a density gauge when it is receiving high fines feed.

Abstract: For operating control and safety, a variable-speed close-coupled pump is direct connected to the underflow of the primary separation vessel (PSV). The desired discharge density of the PSV is 70- 80% solids in order to minimize bitumen losses. For a good pumping system, the pump discharge density should be less than 65% solids to avoid settling out of the solids in the downstream conduit. Therefore it is necessary to dilute the PSV underflow before it reaches the pump. Secondary flotation tailings, a dilute stream containing a high proportion of fine solids, is used for this purpose. The solids content of the PSV underflow is monitored by one of two alternative systems-- a torque recorder on the PSV rake shaft or a density gauge on the PSV underflow conduit. The former is used when the PSV is being fed low fines tar sand-- the latter when it is treating high fines tar sand. The close-coupled pump speed is adjusted relative to the solids content measurement to keep it at the desired 70- 80% level.

Abstract: Ozone is dispersed in river water to be purified and used in a high pressure boiler. The ozone selectively degrades large organic molecules, dissolved in the water, which ordinarily will irreversibly foul the strongly basic anion attracting resin used to adsorb silicious contaminants from the water. The degraded molecules are reduced in resin-fouling capability and are removed from the resin during regeneration.

Abstract: A method of producing viscous materials from subterranean formation comprises a plurality of steps. At least two wells are drilled and completed into the subterranean formation that contains the viscous material. At least one of the wells is completed as an injection well and one of the wells is completed as a production well. A plurality of electrode wells are drilled into the subterranean formation with the plurality of electrode wells being generally arranged in a pattern to define at least one path between the production well and the injection well with the length of the path being substantially greater than the distance between the production well and the injection well. The electrode wells are spaced apart along the path at distances that are substantially less than the distance between the production well and the injection well.

Abstract: An improved electrode for electrically heating a subterranean formation includes a plurality of electrically conductive rod-like members that extend outwardly from a central well bore to provide increased area for conducting electrical current from a source into said subterranean formation. The improved electrode apparatus is adapted to be lowered into a well bore which has been drilled into the subterranean formation and, thereafter, the plurality of rod-like members are driven outwardly from the central well bore. Guide means are provided to direct the rod-like members outwardly into the subterranean formation as a central member is forced downwardly.

Abstract: Coked solids, produced by coking of tar sands, are contacted in a first zone with air and the minimum amount of supplemental fuel needed to burn all the coke. Part of the hot clean mineral solids produced is then discarded; the balance is moved into a second zone. Here supplemental fuel is burned to increase the temperature of the solids. The hot solids from the second zone are recycled to the coking stage.Only part of the solids is heated with supplemental fuel, thereby reducing consumption of the latter. In addition, the flue gas from the second zone is relatively clean and can be vented directly to the atmosphere in the flue gas from the first zone.

Abstract: A single capacitance vessel is provided to receive the excess heavy phase discharges (normally water) from a bank of disc-nozzle centrifugal separators. The vessel has a reservoir chamber with a weir at one end. The heavy phase streams are delivered into the reservoir of fluid retained in this chamber. In the event there are any hydrocarbons in the heavy phase fluid, the former rise to the surface of the reservoir fluid and pass over the weir, together with some water. An inert gas blanket within the vessel pressurizes the reservoir so that a fluid backpressure is maintained at the discharge outlets of the separators. By use of this system, any fluid returned from the reservoir to the separators (which occurs when the feed to the separators is low in water) is substantially free of hydrocarbons which, if present, would deleteriously affect the operation of the separators.

Abstract: Method for reducing the loss of power accompanying the transmission of electrical energy down a wellbore to heat a subterranean formation via electrical conduction between a plurality of wells completed therein, characterized by providing a low frequency alternating current to the conductors in the wellbore. Also disclosed are specific embodiments of the invention.

Abstract: This invention is an improvement on the hot water process for recovering bitumen from tar sand. The aqueous slurry of tar sand is introduced into a first vessel, termed the sand separation cell, containing a body of hot water. The coarse sand settles out and is discharged as tailings. The top product, comprising bitumen, water and fine sand, is transferred to a second vessel, termed the froth formation cell, containing a second body of hot water. In this latter cell, the bitumen forms froth and is recovered, and the fine solids and some water are recycled to the lower end of the sand separation cell. Because the coarse sand has previously been removed in the sand separation cell, good distribution of the feed across the cross-sectional area of the froth formation cell is achieved. This leads to good recoveries and froth quality.