Abstract: A coiled tubing composite comprising insulated coiled tubing, concentric coiled tubing and insulated concentric coil tubing, including structure with centralizers and providing an annulus for insulation. The invention includes a method for assembling concentric coiled tubing, with insulation, and apparatus in combination with the insulated coiled tubing composite for heat assisted production of hydrocarbons and minerals from a wellbore.

Abstract: Apparatus and method for freezing large pipe plugs, including in particular subsea applications, wherein the apparatus includes a jacket adapted to encircle a section of large pipe, a recycling refrigeration unit having said jacket connected as an evaporation chamber and, for subsea applications, a submersible housing enclosing a portion of such refrigeration unit; the method including landing a submersible recycling refrigeration unit on or proximate a pipe and cycling, and preferably reverse cycling, a refrigerant therethrough.

Abstract: A safeguarded method and apparatus for providing fluid communication with coiled tubing, said coiled tubing comprising more particularly coiled-in-coiled tubing, having a inner tube and an outer tube, and including multicentric coiled-in-coiled tubing and its method of assembly, the safeguarded method having particular applicability to drill stem testing.

Abstract: A double acting reciprocating intensifier uses a single low pressure fluid stream as both the power supply and the source of fluid the pressure of which is to be intensified. The entire device, including flow paths, is confined within a compact cylindrical housing. Tandem drive pistons minimize operating frequency, while maximizing intensification ratio and output volume flowrate. Placement of both high pressure cylinders downstream of the drive cylinders permits simple routing of flows through the centers of the low and high pressure pistons. A check valve connected between the high pressure pistons eliminates one of the four high pressure check valves required in the prior art. A single reciprocating valve, whose state is determined by drive and high pressure piston position, coordinates all of the drive side flows. Various components perform multiple functions to permit the compact shape.

Abstract: The invention discloses a process for reducing sludging during acid treatment of an oil well by adding phosphinic acid or a soluble salt thereof and a source of cupric or cuprous ion. The addition of an iodide ion source to this combination aids its effectiveness in stronger acids.