Anti-twist installation method for underwater structures in deep water

Abstract

The invention discloses a twisting-resisting installation method of a deepwater underwater structure. The method comprises the following steps: one, hoisting a structure heavy block to below a winch pulley; two, lifting down the structure heavy block to a set seabed depth to be in place; three, installing and lifting down the deepwater underwater structure, when the deepwater underwater structure is twisted, twisting two short cables installed on the deepwater underwater structure and one end of a horizontal traction cable together, limiting the other end of the horizontal traction cable on a winch guide cable by a sliding shackle, and then producing torque opposite to a twisting direction on the deepwater underwater structure by the horizontal traction cable to prevent the deepwater underwater structure from twisting, and maintaining the balance; and four, cutting off the short cables after the deepwater underwater structure is in place, recovering the structure heavy block and the horizontal traction cable on an installation ship. Through the adoption of the installation method disclosed by the invention, the twisting angle of the deepwater underwater structure in the whole installation lowering process is effectively controlled, so that the deepwater underwater structure is free of the limitation of water depth and environment condition.

Description

technical field [0001] The invention relates to the installation of deep-water underwater structures, in particular to an installation method for anti-rotation of deep-water underwater structures. It belongs to the field of offshore oil engineering. Background technique [0002] As one of the current offshore deepwater oil and gas field development models, the subsea production system is widely used in major oil fields with different water depths around the world. [0003] Deepwater underwater structures (such as: submarine manifolds, subsea pipeline foundation anti-settling plates, umbilical cable terminals, etc.) are important components of underwater production systems, which are generally hoisted and lowered by deepwater support ships through deepwater cranes or deepwater winches installed on the seabed. Since the application area of ​​deep-water underwater structures is relatively deep (from more than 200 meters to several thousand meters), it is impossible to use div...

AI Technical Summary

Problems solved by technology

Such a high precision requirement, and it is carried out without the assistance of divers, is undoubtedly a huge challenge for the installation of deep-water underwater structures

And due to the lack of constraints on the horizontal torsion direction, it is very easy to torsion when it is affected by ship motion and environmental loads, and the deeper the water depth, the more likely the torsion will occur, which affects the horizontal azimuth accuracy of the installation of deep water underwater structures very bad control

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