THREADED CONNECTION OF TUBING STRING FOR OIL WELLS Russian patent published in 2019 - IPC F16L15/04 

FIELD: reinforcement bars production.

SUBSTANCE: invention relates to threaded joint of tubing string for oil wells. Carrying sufficient resistance is provided by preventing its occurrence during threaded connection during verification test, carried out in accordance with ISO 13679:2002, even at small thickness of threaded connection of tubing string for oil wells. Parameters of the threaded connection, including sizes at the established ratio Ls / Ln from 0.2 to 0.6, satisfy formulas: (Ds1²–Ds0²)/(D1²–D0²)≥0.30 and tgθ>(ΔD+δ)/[2(Lt–Ls)], where Ds1 is diameter in inches of outer end of contact surface of end face of nipple pipe part with stop in coupling; Ds0 is diameter in inches of inner end of contact surface of end of nipple part of pipe with stop in coupling; D1 is outer diameter in inches of unshaped section of pipe nipple part; D0 is inner diameter in inches of unshaped section of pipe nipple part; θ is angle of inclination in degrees of coupling seal section; ΔD is the difference ΔD = Dn-Dsp in inches of outer diameter Dn of connecting section of front section of pipe nipple and outer diameter Dsp of sealing point; δ Is the value in inches of tightness in the seal, which is equal to the maximum overlap on the diameter of seal sections of the pipe nipple part and the coupling in the position of the sealing point; Lt is the distance in inches in the axial direction from the final position of the converging part of the coupling seal to the end point of the pipe nipple; Ls is the distance in inches from the end point of the pipe nipple to the sealing point; Ln is length in inches of front section of pipe nipple.

EFFECT: connection of pipes is provided, which has sufficient tightness when external pressure is applied to the threaded connection due to elimination of plastic deformation of the front section and sufficient resistance to scoring.

1 cl, 4 dwg