Wells – Processes – Freeing stuck object – grappling or fishing in well
Patent
1983-04-11
1984-11-27
Novosad, Stephen J.
Wells
Processes
Freeing stuck object, grappling or fishing in well
166 63, 285 81, F21B 3100
Patent
active
044846339
ABSTRACT:
A safety joint for use in a pipe string, particularly one incorporating testing tools, comprising a substantially tubular outer housing with an automatic J-slot cut into the interior surface thereof. A mandrel having a spline radially protruding therefrom along its upper longitudinal extent and a J-slot lug also protruding therefrom below the spline and to a greater radial extent is slidably contained within the housing and is initially prevented from sliding within it by a tension sleeve which is designed to part in response to a predetermined tensile force. To operate the safety joint, the pipe string is set down and right-hand torque applied, after which tension is applied to the pipe string until the tension sleeve parts, whereupon the mandrel moves upwardly with respect to the housing, the J-slot lug being constrained to follow the path of the J-slot. The right-hand torque and upward pipe string movement causes a mandrel retaining nut at the top of the housing to back off therefrom. This sequence is repeated until the nut is completely backed off, whereupon the mandrel will pull free from the housing and all of the string above the housing may be removed from the well bore.
REFERENCES:
patent: 3368829 (1968-02-01), Barrington et al.
patent: 4246964 (1981-01-01), Brandell
Reduced size print entitled "37/8" VR Safety Joint."
Reduced size print entitled "Safety Joint-RTTS 27/8"."
Bui Thuy M.
Halliburton Company
Novosad Stephen J.
Walkowski Joseph A.
Weaver Thomas R.
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