Submarine pipeline expansion bend connecting method suitable for high-precision underwater in-place control

Abstract

The invention relates to the technical field of ocean engineering and discloses a submarine pipeline expansion bend connecting method suitable for high-precision underwater in-place control. The submarine pipeline expansion bend connecting method comprises the following steps that S1, a temporary pipe section with a corresponding length is prefabricated according to the size of an expansion bend along the axial direction of a pipeline; S2, the temporary pipe section is connected with a submarine pipeline through flanges at the two ends of the temporary pipe section on a pipe laying ship, and the temporary pipe section and the submarine pipeline are laid and installed at the same time; S3, after the submarine pipeline is installed on the seabed in place, a diver or an underwater robot is adopted to remove the temporary pipe section by dismantling the flanges; and S4, after the temporary pipe section is removed, the prefabricated expansion bend is located at the reserved position after the original temporary pipe section is removed in a hoisting mode, and underwater connection is conducted on the expansion bend and the submarine pipeline on the two sides through the flanges. By means of the submarine pipeline expansion bend connecting method suitable for the high-precision underwater in-place control, the in-place precision of the connecting pipe ends of the submarine pipeline and the expansion bend can be effectively controlled, and the difficulty of underwater connection of the expansion bend is reduced.

Description

technical field [0001] The invention relates to the technical field of marine engineering, in particular to an expansion-bend connection method of submarine pipelines suitable for high-precision underwater in-position control. Background technique [0002] After the subsea pipeline is abandoned, the underwater expansion bend is flanged to the submarine pipeline by measuring the position of the abandonment point underwater, and the size of the originally designed expansion bend is prefabricated and adjusted according to the construction error of the abandoned pipe at the end of the submarine pipeline. Subsea pipelines are affected by environmental factors such as waves and ocean currents during laying operations. There is usually a certain construction error between the position of the abandoned pipe and the design position, which leads to a certain deviation between the connection position of the submarine pipeline and the expansion bend and the design position. Before the p...

AI Technical Summary

Problems solved by technology

[0004] When the underwater positioning accuracy of submarine pipelines and expansion bends is high, for some sea areas with harsh waves and currents, operating ships and submarine pipelines are more sensitive to the influence of environmental conditions, and the abandonment operation of submarine pipelines is usually difficult to meet The higher precision requirements for discarded pipes have relatively large constraints on construction efficiency; and the adjusted expansion bend shape needs to be re-analyzed and calculated, which will directly restrict the offshore construction period, and underwater measurement and on-site prefabrication will also increase the number of offshore construction projects. The workload and the service life of the operating ship restrict the construction efficiency of the offshore installation of the expansion bend and increase the cost of offshore construction

At the same time, if the installation deviation is large, it will increase the difficulty of the expansion bend for underwater flange connection and increase the risk of underwater construction

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