초록 ▼

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°F. and above. The system consists of an expan

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°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. Various modifications of the system well operate on high temperature, superheated hot water; wet steam; and dry steam.

대표청구항 ▼

A geothermal wellhead system comprising a surface casing cemented in the surface portion of a well bore and extending above the earth surface, a production casing cemented in a well bore inside and extending above said surface casing, a casing head having a tubular body portion secured on said surfa

A geothermal wellhead system comprising a surface casing cemented in the surface portion of a well bore and extending above the earth surface, a production casing cemented in a well bore inside and extending above said surface casing, a casing head having a tubular body portion secured on said surface casing and having an open top end with a surrounding flange having at least one radially extending passageway therein, a hollow member with an opening the same size as said casing head, with a surrounding flange secured to said casing head flange and having at least one radially extending passageway therein, a tubular mandrel secured on said production casing and having a smooth hard cylindrical exterior surface extending through at least part of said casing head and said hollow member, an annular seal assembly positioned adjacent to said flanges in said casing head and said hollow member, said annular seal assembly filling the annular space surrounding said mandrel and having annular pressure activated seals positioned to contact the exterior surface of said mandrel and the interior surface of said casing head and said hollow member, and a high temperature plastic material maintained under pressure against said annular seals and introduced through and filling said radial passageways, the outer ends of said passageways being closed by plug closures.