Abstract: A non-destructive on-site method of inspection, and testing of the insulating performance and reconditioning of a concentric insulating tubular conduit member is disclosed. The insulating tubular conduit members comprise concentric walled members with an intermediate annular insulating cavity defined therebetween. This non-destructive method of testing and inspection is based on a determination of the presence of an unacceptable level of moisture in the annular insulating cavity. Visual, auditory, electrical, and radioactive indicating means can be employed in accordance with the principles of this invention.

Abstract: A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the end of the flared section. The inner tubing member is formed from an initially straight cylindrical member having enlarged ends and, when outwardly flared, the flared ends, although stretched, have a thickness at least equal to the nominal thickness of the inner tubular member. Insulation may be contained within the annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections.

Abstract: A metal-to-metal fluid tight seal configuration formed between two abutting tubular members for use in subterranean oil and gas wells is disclosed. A metal-to-metal fluid tight seal is utilized in a shear release expansion joint assembly mounted by means of an anchor seal assembly in a conventional downhole packer. Sealing engagement is provided by plastic deformation of an annular seal ring between two abutting tubular members which are less ductile than the seal ring. In the preferred embodiment the metal-to-metal fluid tight seal is formed between abutting box and pin tubular members and the plastic deformation of the circular ring occurs as the ring is received within a groove in one of the abutting tubular members which has a dissimilar profile in comparison to the cross-section of the circular ring. Plastic deformation occurs as the box and pin members are rotationally threaded together and a continuous fluid tight seal is maintained along surfaces of both tubular members.

Abstract: A concentric walled conduit for incorporation within a tubular conduit string, and particularly for use in a subterranean well, is provided with one of the walls corrugated for substantially its entire length, preferably the inner tubular member. The annular space defined between the concentric tubular member contains a high heat resistant insulating material disposed around the outer surface of the inner tubular member. Each end of the annular space containing the insulating material is effectively sealed, and secured, such as by welds. The inner wall may be prestressed in tension for counteracting the forces which may be produced by a temperature differential between the tubular member walls of concentric conduit.

Abstract: A split-stream method and apparatus for preventing the accumulation of liquids, such as water or oil, in subterranean gas wells having low shut-in bottom hole pressures is provided. A compressor whose capacity can be less than the theoretical adiabatic horsepower for full wellhead depletion, is used to remove a two-phase liquid-gas mixture through a secondary fluid transmission conduit. Production of dry gas in larger quantities through a primary production conduit is then possible since liquids cannot accumulate to kill the well. An optional mechanism for initiating production in very low pressure wells and a means of preventing the buildup of paraffin is also described.

Abstract: A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the end of the flared section. The inner tubing member is formed from an initially straight cylindrical member having enlarged ends and, when outwardly flared, the flared ends, although stretched, have a thickness at least equal to the nominal thickness of the inner tubular member. Insulation may be contained within the annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections.

Abstract: A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the end of the flared section. The inner tubing member is formed from an initially straight cylindrical member having enlarged ends and, when outwardly flared, the flared ends, although stretched, have a thickness at least equal to the nominal thickness of the inner tubular member. Insulation may be contained within the annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections.

Abstract: A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the end of the flared section. The inner tubing member is formed from an initially straight cylindrical member having enlarged ends and, when outwardly flared, the flared ends, although stretched, have a thickness at least equal to the nominal thickness of the inner tubular member. Insulation may be contained within the annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections.