Abstract: An infrared source for use in an infrared spectrometer includes an insulator core having a containment cavity, an outlet port in communication with the containment cavity, and an electrically heated infrared element mounted in the containment cavity with a portion thereof facing the outlet port and with the walls of the containment cavity closely spaced to the infrared element. The insulator core is formed of a ceramic fiber material which has excellent resistance to heat and very low thermal conductivity so that very little heat from the infrared element escapes from the insulator core except as infrared radiation through the outlet port. The insulator core is preferably mounted within a central cavity of a metal housing, and may be sealed off from the ambient atmosphere by an infrared transmissive window sealed to an outlet opening in the housing.

Abstract: Petroleum materials may be effectively recovered from subterranean, viscous, asphaltic or bituminous formations such as tar sand deposits by first injecting into the tar sand formation a paraffinic hydrocarbon at a temperature below 300.degree. F which precipitates asphaltic material from the asphaltic petroleum in the formation. Next, solvent injection is terminated and air is injected into the formation, and the formation is ignited to accomplish in situ combustion within the tar sand reservoir utilizing the precipitated asphaltic materials for fuel for the in situ combustion reaction. Reaction temperatures higher than normal in situ combustion temperatures are produced, facilitating thermal cracking and in situ hydrogenation to up grade the produced crude within the tar sand reservoir.

Abstract: Viscous petroleum may be recovered from viscous petroleum-containing formations including tar sand deposits by contacting the formation with a heated multiple-component solvent for the petroleum. At least one solvent component is normally gaseous material such as methane, ethane, propane or butane and at least one component is normally liquid, such as pentane and higher molecular weight hydrocarbons. The solvent mixture is heated to a temperature in excess of ambient temperature, and preferably from 100.degree. to 500.degree. F. prior to injection into the formation. The multiple solvent is introduced under sufficient pressure that it is substantially all liquid at the injection conditions. Recovery of petroleum and solvent may be from the same well as is used for injection or from a remotely located well.

Abstract: Petroleum may be recovered from viscous petroleum-containing formations including tar sand deposits by injecting into the formation a multiple-component solvent for the petroleum. At least one solvent component is gaseous at the temperature and pressure of the petroleum reservoir such as carbon dioxide, methane, ethane, propane, butane or pentane and at least one component is liquid at the reservoir conditions, such as hexane and higher molecular weight aliphatic or aromatic hydrocarbons. The multiple solvent is preferably introduced under sufficient pressure that it is substantially all in the liquid phase. Recovery of petroleum and solvent may be from the same well as is used for injection or from a remotely located well. When the pressure in a portion of the formation contacted by the solvents is reduced below the vapor pressure of the gaseous solvent, it vaporizes to provide drive energy for oil production. The liquid components dissolve in the petroleum and reduce the petroleum viscosity.