Abstract: The present disclosure sets forth the method and apparatus for installing a casing in a geothermal well. Procedurally, the well is drilled toward but not into the geothermal zone of interest, a surface conductor pipe is cemented in place, a casing sting is then positioned in the well borehole and the bottom portions thereof is cemented in place, tension is then placed in the casing string, and the top end is anchored. With tension in the casing string, wellhead completion steps are carried out and production upwardly the casing string causes the casing string to elongate and thereby reduces the tension in the casing string. An apparatus is disclosed including an external spool having an outer groove which is locked in position with a set of lock pins. The spool has a set of slips of wedge shaped construction on the interior which grip the casing when subjected to hydraulic pressure. This enables the casing string to be held firmly without slipping at the wellhead.

Abstract: A high pressure shut-off valve has a hollow valve body with an open end, closed end and a cylindrical cavity with a cover. Aligned inlet and outlet portions form a straight bore intersecting the valve cavity. A plug valve assembly has a supporting mandrel reciprocally slidable to a position abutting the valve cavity closed end, with an end portion having a transverse valve passage and an intermediate portion for closing the valve body bore, the valve passage being aligned with the bore when retracted. An elastomeric sealing sleeve member on the mandrel seals the cavity wall around the bore when the valve is closed. A mon-rising threaded stem, operated by a hand wheel, moves the valve assembly and has a lost motion connection operable on overtravel to compress the sleeve member longitudinally along the mandrel. Metal discs supported integrally on a supporting sleeve fill holes in the sleeve member to prevent extrusion of the sleeve into the bore.

Abstract: A geothermal expansion wellhead system is provided which adapts the wellhead and control valves to the casing in the wellbore. The system suspends and seals the casing while expanding and contracting during geothermal operations at temperatures up to 550.degree. F. and above. The system consists of an expansion spool in which there is mounted an expansion mandrel which is secured on the end of the production casing extending out of a cemented geothermal well. The expansion mandrel has a hard smooth surface, preferably produced by electroplating. Annular seals seal the annulus between the expansion mandrel and the expansion spool and have a sliding engagement with the hard smooth surface of the expansion mandrel. The annular seals are energized by pressurization with a high temperature plastic composition and the seal may be re-energized at any time during operation. The expansion mandrel includes scraper elements which scrape off corrosion or other deposits on the inner surface of the expansion spool.

Abstract: An improved valve is disclosed. In the preferred and illustrated embodiment, the valve utilizes a flat disk within a valve body, the disk supporting a peripheral groove having bearings therein for alignment and to enable rotation, and further includes pressure balanced opposing faces and receives a valve seat therein. The flat disk and body arrangement reduces the size of a large valve and reduces the wear occurring on the valve seat and seal mechanism. Alternate embodiments and configurations are disclosed.

Abstract: A variable high pressure choke consists of a hollow valve body having a cylindrical cavity with a closed end, an open end and a cover or closure for the open end, and aligned tubular inlet and outlet portions on opposite sides thereof defining a straight bore intersecting the cavity at a right angle thereto. A tubular seal member is positioned in the bore with an end portion movable end-wise into the valve cavity. A flow selector member positioned in the cavity has a solid portion and a portion with flow controlling passages of different sizes; has a sliding fit between an extended position with the solid portion closing off the seal member end portion and successively retracted positions along the seal member to provide fluid flow openings of different sizes through the valve body. An operating stem connected to the flow selector has a threaded connection in the cover whereby rotation of the stem by a hand wheel raises the stem to move the flow selector.

Abstract: A high pressure shut-off valve consists of a hollow valve body having an open end, a closed end and a cylindrical cavity with a cover therefor. Aligned tubular inlet and outlet portions on opposite sides of the valve body form a continuous straight bore intersecting the cavity at a right angle thereto. A plug valve assembly positioned in the valve body cavity has a supporting mandrel a slidable therein between an extended position abutting the closed end and a retracted position some distance therefrom. The mandrel has an end portion with a laterally extending valve passage and an intermediate portion closing the valve body bore when in the extended position, the valve passage being aligned with the bore when in the retracted position. A sealing sleeve member of elastomeric material surrounds the mandrel intermediate portion and engages the entire circumferential wall of the cavity around the bore to seal against leakage when the valve is closed.

Abstract: An improved valve is disclosed. In the preferred and illustrated embodiment, the valve utilizes a flat disk within a valve body, the disk supporting a peripheral groove having bearings therein for alignment and to enable rotation, and further includes pressure balanced opposing faces and receives a valve seat therein. The flat disk and body arrangement reduces the size of a large valve and reduces the wear occurring on the valve seat and seal mechanism. Alternate embodiments and configurations are disclosed.