APPARATUS AND METHOD FOR RETRIEVING AND/OR COMMUNICATING WITH DOWNHOLE EQUIPMENT

摘要

Method and apparatus for fishing for and/or communicating with subsurface apparatus. In a preferred embodiment, a subsurface logging-while-drilling (5)(LWD) or measuring-while-drilling (MWD) apparatus is placed in tandem with a drill string near the bottom of a borehole. The LWD apparatus includes a surface retrievable component such as a nuclear source carrier with a fishing head facing (53) upwardly. The carrier is releasably secured within the LWD apparatus with means such as a shear pin (19). A wireline conveyed tool (10) having a downwardly facing latching mechanism (153) includes a downhole powered latch for telescopically extending beyond the fishing head (53), forcing a latching lug radially inwardly below the fishing head, and moving axially upward to latch the fishing head. Further upward latch movement causes the fishing head (53) to move upwardly until the shear pin (19) shears which releases the carrier from the subsurface apparatus. The wireline tool (10) with the attached carrier is then brought to surface with the wireline cable (6). In a preferred embodiment, the subsurface apparatus includes a secondary coil (50) within its tubular housing. A primary coil (59) is provided on the wireline tool (10) such that upon the wireline tool landing within the subsurface apparatus, the primary coil is nested within the secondary coil. As a result, a bi-directional communication link is established from surface instrumentation to the subsurface apparatus via the wireline cable (6) and the nested coils.