Repair method for external corrosion defect of submarine pipeline

Abstract

The invention discloses a maintenance method for an external corrosion defect of a submarine pipeline. The maintenance method comprises the following step (1) of polishing and cleaning the corrosion defect; the step (2) of filling corrosion pits cleaned in the step (1) with repair agents, pressing and trowelling the corrosion pits, and removing seawater; (3) the corrosion defect position of a pipe wall is wound in a lap joint mode through an alkali-free glass fiber belt coated with binders on the front side and the back side; and (4) the corrosion defect position of the pipe wall in the lap joint mode is wound through a reinforced winding belt, and therefore the yield strength of the corrosion defect position is recovered to the state before corrosion; the step (5) of installing a grouting mold at a repair area when the reinforced winding belt reaches the curing hardness, then pouring high-strength cement to remove seawater, till the grouting operation is completed after grout is returned from a grout return port; and forming a concrete balance weight insulation protection layer after the high-strength cement is solidified, and finishing maintenance. According to the repair method, the corrosion development can be effectively controlled; the pipeline property is not changed, the integrity of the pipeline can be kept, and magnetic flux leakage detection is facilitated; the construction is convenient; the requirement for construction resources is low; and the construction cost is low.

Description

technical field [0001] The invention relates to a maintenance method for pipelines, in particular to a maintenance method for external corrosion defects of submarine pipelines. Background technique [0002] Pipeline transportation is the main transportation mode of oil and natural gas. In-service pipelines are exposed to harsh working environments such as mud or seawater for a long time, which may cause external corrosion of the pipe wall of the oil pipeline, and even leak in severe cases, causing serious environmental pollution and property loss. Therefore, it is very important to repair the defects of oil and gas pipelines. [0003] In recent years, the inspection results in the pipeline show that some of the single-layer concrete counterweight insulation pipes have a certain amount of external corrosion. It is not clear whether the sacrificial anode of this type of pipeline can play the role of cathodic protection, but the fact proves that the external corrosion has not...

AI Technical Summary

Problems solved by technology

[0008] 3) Affected by the ovality of the pipeline, there is a possibility of failure;

[0009] 4) The requirements for construction resources are relatively high, and large-scale equipment such as floating cranes is required, and the overall construction cost is relatively high

[0011] 1) The requirements for construction resources are relatively high, large-scale equipment such as floating cranes is required, and the overall construction cost is relatively high;

[0012] 2) Production needs to be stopped during construction, and the cost is high