| 摘要 |
<p>An integrally formed, solid casing centralizer (130) for centering casing strings in oil and gas wells. The casing centralizer (130) comprises a central body (135) having a bore (160) adapted to closely engage a casing string and a plurality of integral blades (140) radiating outwardly from the central body. The centralizer (130) is formed by heating a billet of suitable metal to a temperature sufficient to render said billet malleable for extrusion yet which is substantially below a melting temperature of said billet, forcing the metal through a die (10) thereby forming a workpiece having a profile suitable to form a desired cross-sectional shape of a casing centralizer; cooling the extruded workpiece, and cutting the cooled, extruded workpiece into sections, each section having a length sufficient to form a casing centralizer (130). Each end of each blade (140) may be bevelled (140a) to ease passage of the centralizer into the wellbore, and lock screws (170) may be provided in threaded holes (180) penetrating the central body and blades (140) to fix the centralizers at desired locations on the casing string. The present invention results in an extrud ed solid casing centralizer (130) substantially free of gas inclusions in the metal, resulting in high strength with minimum dimensions and thereby retaining maximum annular flow area. The extruded centralizer, without further finish work, typically has an overall surface finish RMS value of approximately 125 micro inches.</p> |
