METHOD FOR REPAIRING DEFECTIVE SECTIONS OF MAIN PIPELINES Russian patent published in 2023 - IPC F16L1/28 F16L1/10 

FIELD: oil and gas pipelines.

SUBSTANCE: repair of main oil and gas pipelines by replacing the defective section of the pipeline. The method of repair consists in localizing the defective section, digging it out, fixing the pipeline with fixing devices, cutting, centering the ends of the pipeline, and replacing it. After digging out the pipeline, geodetic measurements of its vertical and planned position in the repair pit are carried out. By approximating the measurements by a polynomial of the fourth degree, the values of its coefficients are obtained. Based on these values and data on the pipeline wall material, its length, outer and inner diameters, the lengths of the left and right sides of the pipeline section along the edges of one of the pipeline cutting points, as well as the number of fixing and centering devices installed on the pipeline and the horizontal coordinates of their installation sites, determine the magnitude of the reaction forces that occur in the power cylinders with a sharp displacement of the pipeline ends. Then, the values of the maximum stresses that occur in the pipeline wall when its ends are centered, are determined. When the values of the reaction forces in the power cylinders and the maximum stresses arising in the pipeline wall exceed their permissible values, the warning system is triggered. After that, additional digging of the repaired area and geodetic measurements of the altitude-planned position of the pipeline are carried out. Fixing and centering devices are installed along the edges from each pipeline cutting point at a distance of at least 0.5 m.

EFFECT: ensuring the industrial safety of the repair process by fixing the position of the pipeline ends before cutting it and centering them before welding a new section.

1 cl, 6 dwg, 3 tbl