| 摘要 |
<p>A tubular member, to be a segment of the casing string, is provided with a polished bore at its upper end and a locking profile at its lower end. The locking profile includes a bearing shoulder and internal left hand threads for coaction with a latching mechanism. Another tubular member, to be a segment of the production tubing, has groups of circumferentially separated flutes to (1) maintain concentricity of the tubing segment, (2) provide axial flow passages between the segments, and (3) provide support for components of the tubing segment. A tubular packing mandrel, mounted on flutes, carries external annular packing for sealing engagement with the polished bore. The lower end of the packing mandrel defines an annular valve seat; and a tubular valve closure member, mounted in sliding, sealing relation on the tubing segment, has a coacting upward facing valve seat. A valve spring urges closure of the valve closure member. Lower flutes define a bearing shoulder for coaction with the casing shoulder to support the tubing string. A latching mechanism includes circumferentially separated axially extending spring fingers carrying external threads for coacting ratcheting and threaded engagement with the profile threads. When the tubing string is lowered to the support position provided by the bearing shoulders, the tubing segment is locked within the casing segment.</p> |
