USE OF COMPENSATORS IN THE UNDERWATER SECTION OF THE OFFSHORE GAS PIPELINE TO PREVENT ITS SURFACING

Abstract

The relevance of the study lies in preventing the surfacing of underwater sections of the offshore gas pipeline and keeping them in the design position. Purpose: identification of the length of the blurred exposed part, soil condition on the adjacent underground parts, internal pressure and temperature stresses for the ascent of the underwater section of the gas pipeline, as well as the establishment of effective operation of compensators. Objects: underwater sections of the gas pipeline, expansion joints. Methods: joint integration of a system of differential equations describing the stress-strain state of a blurred exposed part and adjacent underground parts. Results. The paper introduces brief information about the ascent of two of four threads of the Nord Stream-2 at the site of the underwater passage through the Baydaratskaya Bay in Yamal. The following three statements of the problem of the stress-strain state of the calculated underwater section of the gas pipeline are considered: taking into account the effect of internal pressure and temperature stresses on the bending of the pipeline, causing additional bending of the gas pipeline; neglecting the effect of internal pressure and temperature stresses on the bending of the pipeline; with compensators installed at the beginning and end of the calculated section. The presented solution for the first formulation of the problem depends on the usual trigonometric functions, for the second formulation of the problem – on polynomials, and in the third formulation – on hyperbolic and trigonometric functions. For these three problem statements, the main characteristics of the stress-strain state of the gas pipeline are calculated, diagrams of its deflection and bending stresses are constructed, the tables show the extreme values of these characteristics for different values of the parameters of the operation of the gas pipeline for different lengths of the blurred exposed part, and taking into account changes in soil state on adjacent underground parts. The effective operation of compensators designed to prevent the surfacing of underwater sections of the offshore gas pipeline and to keep them in the design position was established.

Keywords

• gas pipeline
• soil
• deflection
• stress
• pressure
• compensator