摘要 |
FIELD: oil and gas industry.SUBSTANCE: invention is referred to tubing string having silicate enamel coating at inner surface. At outer surface of the string ends there is a tool for tubes connection made as threaded sections. At that according to the invention silicate enamel coating at inner surface of tubes is modelled at substrate. Substrate is formed with area having removed layer of metal surface with depth from 60 mcm up to 80 mcm. At that substrate length exceeds length of threaded section at outer surface of the tube 2.1-2.3 times.EFFECT: increase of the string service life.1 cl, 1 dwg |