Abstract: A method and an apparatus for determining the interfacial or surface tension, static or dynamic, between two liquids or between a gas and a liquid under conditions of varying temperature and pressure; and a method for adjusting the interfacial or surface tension in a petroleum reservoir for enhanced oil recovery. A tensiometer is provided which is capable of measuring interfacial or surface tension under pressure and temperature conditions which simulate those present in an actual petroleum reservoir. Measuring the interfacial and surface tension values under actual reservoir conditions then enables the selection of surfactants and other materials for adjusting the interfacial and surface tension to desired values for optimizing the enhanced oil recovery from that reservoir. A tensiometer is provided which includes a calibration body which is imaged along with the image of the test droplet in the tensiometer chamber.

Abstract: A process is provided for enhancing the recovery of oil in a subterranean formation. The process involves injecting a surfactant-containing foam having oil-imbibing and transporting properties. A foam having such properties is selected either by determination of the lamella number or by micro-visualization techniques.

Abstract: A process is provided for enhancing the recovery of oil in a subterranean formation. The process involves injecting a surfactant-containing foam having oil-imbibing and transporting properties. A foam having such properties is selected either by determination of the lamella number or by micro-visualization techniques.

Abstract: The present invention is based on the following:(1) that when tar sand is conditioned and diluted in the hot water extraction process, there are two classes of anionic surfactants (originating from carboxylate and sulfonate groups) present in the process water;(2) that each of these surfactants has the potential to dominantly influence the maximizing of primary froth production by the process;(3) that it is possible for a particular extraction circuit to determine the critical free surfactant concentration in the process water at which primary froth extraction is maximized for each of the two classes of surfactant;(4) and that it is possible to determine which of the two classes of surfactant will first (that is, at lowest NaOH addition) dominate the process when a particular tar sand feed is being processed.The present invention therefore involves:determining the critical free surfactant concentrations ("C.sub.cs.sup.O " and "C.sub.ss.sup.

Abstract: The hot water process is controlled in response to viscosity measurements taken in situ in the middlings in the primary separation vessel. The viscosity in the middlings is found to vary. Therefore, the layer of maximum viscosity is located and the viscosity at this depth is monitored. Adjustments are made to the process to keep this maximum viscosity below a pre-determined limit.

Abstract: Two or more tar sand feeds are blended in specified proportions in combination with a specified dosage of NaOH to provide a slurry, having a free surfactant content dissolved in the aqueous phase of the slurry, which yields the maximum possible primary froth production from the hot water extraction process.

Abstract: The hot water process is sensitive to the nature of the tar sand feed, which varies. An alkaline process aid, usually NaOH, is normally added to the conditioning step of the process and is needed to obtain good bitumen recovery from most tar sand feeds. The invention is based on the discovery that, for a particular extraction circuit used, there is a single value of free surfactant content in the aqueous phase of the process slurry which will yield maximum primary froth recovery regardless of the type of tar sand feed used.