An optimization method for buoyancy block configuration of deepwater drilling riser system based on genetic algorithm

Abstract

The invention discloses a method for optimizing the buoyancy block configuration of a deepwater drilling riser system based on a genetic algorithm, which is characterized by the following steps: S1: taking the buoyancy block configuration of the riser system as an optimization variable, and characterizing the riser in the form of genetic code System buoyancy block configuration; S2: Establish a vortex-induced fatigue analysis model of the riser system to determine the vortex-induced fatigue damage at any position of the riser system; S3: Determine the occurrence probability of different sea current flow rates to reduce the long-term vortex-induced fatigue of the riser system Establish the buoyancy block configuration optimization objective function of the riser system with damage as the target; S4: Establish a buoyancy block configuration optimization method based on genetic algorithm, through the mechanism of natural selection, mutation and crossover of genes, new buoyant block configuration gene populations are continuously generated, and the The buoyancy block configuration scheme is optimized. The invention can be used to quickly and accurately determine the buoyancy block configuration scheme of the deepwater drilling riser system with better vortex-induced suppression effect.

Description

technical field [0001] The invention belongs to the field of marine oil and gas engineering, and in particular relates to a method for optimizing configuration of buoyancy blocks of a deep water drilling riser system based on a genetic algorithm in the process of marine deep water oil and gas drilling. Background technique [0002] During deepwater oil and gas drilling and production, the drilling riser system is the key equipment connecting the subsea wellhead and the offshore drilling platform. It has been in a complex marine environment for a long time. When the seawater flows through the riser system, alternate vortex discharges are generated on both sides, making The riser produces vortex-induced vibration, especially when the vortex shedding frequency is close to the transverse natural frequency of the riser, the vortex-induced vibration is more obvious, which can easily cause fatigue damage or even fracture of the riser system. Therefore, the vortex-induced fatigue of ...

AI Technical Summary

Problems solved by technology

The current research mainly destroys the vortex by installing riser spiral strakes, shock absorbers and other vortex suppression devices to achieve the effect of vortex suppression. However, the installation and disassembly of these devices will complicate the operation process of the riser, especially in deep water. In the case of frequent lowering and recovery, the operation time is greatly prolonged; in addition, if the vortex-induced suppression device is installed improperly, the vibration will be aggravated, so the vortex-induced suppression device for drilling risers is basically not used in the project

[0003] Due to its high gravity, the riser system needs to install a certain number of buoyancy blocks. At present, some scholars propose to use riser buoyancy blocks to reduce vortex-induced suppression under the premise of meeting the operational needs of deepwater drilling riser systems. Several different coverage ratios of buoyancy blocks are used to obtain configuration schemes that can suppress vortex-induced vibration of risers. These schemes have obvious limitations

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