Wireline cable head for use in coiled tubing operations
AssigneeWestern Atlas International, Inc.
InventorNicholas J. Arend
Life of this patent
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Abstract
The invention is a wireline cable head adapted to be used on a wireline tool string which is conveyed into a wellbore by a coiled tubing. The cable head comprises a biased, piston-type check valve which enables fluid circulation from the tubing into the wellbore, but prevents fluid flow from the wellbore into the coiled tubing. The biasing means maintains a minimum differential pressure which must be pumped into the coiled tubing to enable fluid circulation from the coiled tubing into the wellbore. The cable head also comprises a bulkhead for maintaining hydraulic integrity of the cable head after the cable is extracted from the cable head.
Claims4
An electric wireline cable head, adapted to be conveyed by a coiled tubing having a coaxially inserted cable, into a wellbore penetrating an earth formation, said cable head comprising an apparatus for enabling fluid flow from the interior of said coiled tubing into said wellbore and for preventing fluid flow from said wellbore into the interior of said coiled tubing, said apparatus comprising:
- a housing affixed to said cable head, said housing having at least one fluid discharge hole in fluid communication with said wellbore;
- a piston, slideably mounted within said housing, said piston at one end in fluid communication with the interior of said coiled tubing and at the other end in fluid communication with said wellbore;
- and
- biasing means, for forcing said piston against fluid flow from the interior of said coiled tubing, so that a fluid having a pressure which exceeds the sum of the pressure within said wellbore and the pressure exerted by said biasing means against said piston, pumped into said coiled tubing, causes said piston to move, causing said at least one fluid discharge hole to be in fluid communication with said wellbore, thereby enabling fluid flow from said coiled tubing into said wellbore.
Dependencies are inferred from the claim text.