Abstract: A dognut for use in the installation of a string of coiled tubing in an oil or gas well features a construction and assembly which enables the dognut to be installed on the tubing, the dognut and tubing to be landed in place in the tubing spool, the dognut seal to be activated and the assembly of the dognut, dognut seal, tubing and tubing spool to be pressure tested for leakage prior to cutting the coiled tubing above the dognut and putting the wellhead under pressure from the producing formation. This dognut installation adds to the safety and ease of completing the coiled tubing installation in oil or gas wells.

Abstract: There is disclosed an apparatus including a tubing spool and tubing hanger which overcomes problems associated with servicing of oil and gas wells under pressure. In the invention, a tubing hanger can move through a tubing spool and be seated and sealed from the outside the tubing spool. The tubing hanger includes a flexible packing element with means for engaging and expanding the element to the tubing hanger in the tubing spool and a plurality of locking means adapted to secure the dognut in relation to the tubing spool.