Electrical power sources and systems for heating in or adjacent to an oil well or other mineral well, or for heating other earth media, each comprising an A.C. heating generator that generates an A.C. heating current at a selected heating frequency substantially different from the conventional 50/60 Hz frequency used by power companies; the heating generator may comprise an A.C. to D.C. converter for developing an intermediate D.C. output of predetermined amplitude from a conventional 50/60 Hz A.C. input, and a solid state switching circuit for repetitively sampling the D.C. output of the converter at the selected heating frequency, usually in a range of 0.01 Hz (or even lower) up to about 35 Hz. A heating rate control varies the energy content and the frequency of the A.C. output to suit well requirements. Each power source or system includes output connections for connecting the output of the heating generator to a normally inaccessible main heating electrode, usually located downhole in a well, and to a return electrode; most have the capability of including a very small controllable D.C. component in the output.

@ A method and apparatus for treating very large pipe sections such as those used for oil or gas wells, in which one or both cyclindrical surfaces of the pipe sections are processed entirely throughout the length and circumference of the pipe, in one cycle of operation. The processing comprises cleaning and one or more of the following treatments: inspection, coating with a corrosion preventative material and forced-air drying and the inspection process will include remote optical/video scanning of the whole circumference of the pipe. The preferred apparatus comprises a bed (1a) on which the pipe section is supported, an external processing unit (9) and a probe (8), both of which are advanced down the pipe section and retracted with a fixed spatial relationship and both of which contain means for treating the respective pipe surfaces. In a second embodiment the probe is used on its own as a means for , cleaning and inspecting down-hole pipe conditions around 360° of the circumference of the pipes.

Zur Beseitigung von H₂S aus Erdgas, Erdöl und deren Gemischen, versetzt man das aus der Erde geförderte, wasserhaltige Erdgas, Erdöl oder deren Gemisch bei erhöhtem Druck und gegebenenfalls erhöhter Temperatur mit einer wässrigen H₂0₂-Lösung und läßt in einem Reaktor unter Aufrechterhaltung des erhöhten Drucks unter Mischungsbedingungen mindestens so lange reagieren, bis in der Erdgasphase bzw. Erdölphase die gewünschte Herabsetzung des H₂S-Gehaltes eingetreten ist.

The present invention relates to a downhole completion system arranged in a borehole of a well for producing hydrocarbon-containing fluid from a reservoir, comprising a well tubular metal structure forming a conduit for conducting fluid, the well tubular structure having an inner face and an outer face, and at least one metal component mounted as part of the well tubular metal structure and having an inner component face, wherein the inner component face is at least partly covered by an ion diffusion barrier.