| 摘要 |
Coring apparatus (10) and method are disclosed which provide for hydrauli c latching of an inner core barrel (26) within an outer core barrel (12). The apparatus includes a valve face (48) disposed around the inner core barrel (26) and valve seat (52) disposed around the bore of the outer core barrel (12) that close to fo rm a restriction in drilling fluid flow path (54). A hydraulic differential force is thereby created which holds the inner barrel (26) in place. Axially oriented bores (64) in a hanger assembly (58) and in stabilizers (62) ace disposed along the inner co re barrel (26) to provide a flow path for the drilling fluid after the restriction is formed. The bores are calibrated to produce a pre-determined hydraulic force on the inne r barrel (26). A bearing assembly (30) is used to prevent transmission of outer barre l (12) rotation to the inner core barrel (26). The outer surface of the bearing assembly (30) forms the valve face (48) so as to form the drilling fluid restriction and also provides an axial stop that prevents further axial movement of the inner barrel (26) towards the core head (14).
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