| 摘要 |
This invention relates to a system for controlling wax formation in oil wells using a thermal syphon wherein a confined annular space between the production tube and the oil string casing is provided by means of a plug, or "packer", installed at a point well below the level at which solid waxes begin to deposit out of the exiting crude oil and a plug, or "packer", installed above the point at which waxes would otherwise stop depositing out of the exiting crude oil and thereafter filling the confined annulus with a fluid working medium. The quantity and properties of the fluid working medium are arranged such that the medium is vaporized at the lower extremeties of the confined annulus and condensed on the surfaces of the upper regions of the confined annulus, particularly in the zone of wax deposition. The condensation process warms the production tube sufficiently to prevent formation of adhesive wax deposits or, alternatively, reliquifies a thin film of deposited wax which enables the flowing crude oil to remove the deposited wax. The condensed working medium flows by gravity to the lower part of the confined annulus where it again becomes available for vaporization and subsequent condensation. No external power is used for this circulation which is caused solely by temperature differences between lower and higher levels of the annulus.
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