A method for inhibiting or preventing the deposition of metals onto metallic surfaces, particularly the metal surfaces in an oil or gas well is disclosed.

This invention relates to a downhole activated device for providing cathodic protection for pipes in a wellbore for the production of hydrocarbons. The downhole activated devices are carried within either the pipe casing or the collars or both and remain generally within the maximum outward profile of the pipe string so as not to interfere with the movement and placement of the pipe string in the wellbore. The pipe string may be rotated, reciprocated and circulated which enhances the ability of the installer to place the pipe string in a deviated or long reach wellbore. Once the pipe string is in place, the devices may be deployed by one of several methods such that pistons mounted in openings in the peripheral wall of the pipe string move outwardly to contact the wall of the wellbore. Such contact with the walls of the wellbore insures that the sacrificial material in the pistons will corrode in preference to the remainder of the pipe.

In a well pumping unit of the type employing a polished rod, a stuffing box is disposed at the upper end of the wellhead which has axially spaced bearing assemblies, and packing coils positioned between a bearing section at either end of each assembly to guide the polished rod for reciprocal movement along a vertical path through the wellhead, each bearing section having annular portions connected together in end-to-end relation with one portion composed of brass and another portion composed of zinc which is capable of undergoing a reduction reaction with the oxygen present in the liquids and gases to effectively reduce corrosion of the polished rod.

A sliding sleeve casing tool installed in a casing string comprising a housing, sliding sleeve, seal members and releasable retaining means to retain the sliding sleeve within the desired locations with the housing.

This invention relates to a downhole activated centralizer for centralizing pipes in a wellbore for the exploration and production of hydrocarbons. The downhole activated centralizers are carried within either the pipe casing or the collars or both and remain generally within the maximum outward profile of the pipe string so as not to interfere with the movement and placement of the pipe string in the wellbore. The pipe string may be rotated, reciprocated and circulated which enhances the ability of the installer to place the pipe string in a deviated or long reach wellbore. Once the pipe string is in place, the centralizers may be deployed by one of several methods such that pistons mounted in openings in the peripheral wall of the pipe string move outwardly with sufficient force to move the pipe string way from the walls of the wellbore sufficient to form a complete annulus for cementing. Once the well is cemented, the plugs in the tubular pistons may be destroyed by one of several methods opening perforations to the formation.