METHOD TO PROTECT INNER SURFACE OF WELL TUBING STRINGS WITH COUPLINGS OF THREADED CONNECTION AGAINST CORROSION AND DEPOSITS (VERSIONS) Russian patent published in 2012 - IPC F16L58/00 F16L15/04 

FIELD: machine building.

SUBSTANCE: method to protect an inner surface of well tubing strings with couplings of threaded connection against corrosion and deposits, in which at first each coupling at one end is connected with a pipe along the thread, and at the other one - with a bushing with the thread. Connection with the bushing is carried out by the value, which is smaller than the length of the coupling thread by 18-21 mm. Then the protective coating of the inner surface of the pipe and coupling is arranged with an epoxide phenylene enamel ARGOF-EP in two layers of total thickness of 60-280 mcm. Then a bushing is screwed out from the coupling, and at this end the coupling is connected to a free end of the next pipe. As a version, a protective coating is proposed for the inner surface of the pipe and the coupling in two layers, the first of which with the thickness of 30-140 mcm is carried out with the epoxide-phenylene enamel ARGOF-EP, and the second layer with the thickness of 30-140 mcm - with the bromated epoxide phenylene enamel ARGOF-EPB.

EFFECT: increased resource and reliability, and also repairability under operation conditions.

2 cl