Patent ID: 7347256

Claim:
Apparatus for extracting fluid from a subterranean well, comprising: a vessel for receiving fluid from the well, said vessel extending along an axis; a discharge head structure connectable to an upper portion of the well and useable to remove well fluid from said vessel, wherein said discharge head structure telescopingly receives an upper axial portion of said vessel when said vessel is in said second position, and said resilient portion of said seal apparatus is externally carried on and coaxially circumscribes said upper axial portion of said vessel; a system selectively operable to axially lower said vessel into the well to a first position to receive well fluid, and lift said vessel from said first position to a second position in which said discharge head structure and said vessel are forcibly interengaged in a telescoped relationship for removal of the received well fluid using said discharge head structure; and a seal apparatus for creating a peripheral seal between telescoped portions of said discharge head structure and said vessel, said seal apparatus having a resilient portion which, with said vessel in said second position, resiliently biases said vessel axially toward said second position to facilitate release of said vessel from said discharge head structure.