| 摘要 |
Coring apparatus and method are disclosed which provide for hydraulic latching of an inner core barrel within an outer core barrel. The apparatus includes a valve face disposed around the inner core barrel and valve seat disposed around the bore of the outer core barrel that close to form a restriction in the drilling fluid flow path. A hydraulic differential force is thereby created which holds the inner barrel in place. Axially oriented bores in a hanger assembly and in stabilizers are disposed along the inner core barrel 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 inner barrel. A bearing assembly is used to prevent transmission of outer barrel rotation to the inner core barrel. The outer surface of the bearing assembly forms the valve face so as to form the drilling fluid restriction and also provides an axial stop that prevents further axial movement of the inner barrel towards the core head.
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