Early warning method, control method and system for harmful flow type of oil-gas collecting and conveying vertical pipe system

Abstract

The invention discloses an early warning method, a control method and a system for a harmful flow type of an oil-gas collecting and conveying vertical pipe system. A normal submarine pipeline and a liquid plug forming mechanism at the bottom of a vertical pipe and liquid plug forming position parameters are adopted to carry out support vector machine training; then continuous rapid identificationis carried out on the overall flow type in the pipeline of at least three differential pressure signals on the collecting and conveying vertical pipe system, and a dimensionless mean value of the differential pressure signal is obtained; according to the rapid response of the flow changes through monitoring the formation of a long liquid plug in the submarine pipeline and the mean value of each differential pressure signal, so that the early warning of the instability of the gas-liquid interface and the liquid plug caused by the pipeline structure is realized, and the liquid plug forming positions, weather in the submarine pipeline and the bottom of the vertical pipe, can be correspondingly forecast, so that accurate judgment of the position of the liquid plug is realized; after the earlywarning is sent out, enough time is provided for the control device to respond, so that the formation of the harmful flow type can be avoided or the damage caused by the harmful flow type can be avoided; the method has the advantages that the early warning reliability is high, the false alarm rate is low, and the margin of the flow safety guarantee can be remarkably improved.

Description

technical field [0001] The invention belongs to the field of flow safety assurance in offshore oil and gas fields, and in particular relates to an early warning method, a control method and a system for harmful flow patterns of an oil and gas gathering and transportation standpipe system. Background technique [0002] In offshore oil and gas development, products such as oil and gas produced from the seabed are lifted to the offshore production platform through pipelines. Since a platform usually collects the output of multiple oil wells, the distance between each oil well and the platform is relatively long. After the pipeline is led out from the wellhead, it is first laid along the seabed, and after reaching the bottom of the platform, it leaves the seabed to reach the sea surface; The pipe section of the offshore platform is called the riser. When the gas-liquid flow rate is low, a long liquid plug is easily formed in the standpipe, which flows out alternately with the g...

AI Technical Summary

Problems solved by technology

[0008] However, the use of the above existing technologies is only used to prevent overpressure of the pipeline, not to monitor the formation of severe liquid plug flow, mainly to avoid installing sensors on the seabed

The research of the paper (Zou et al., Experimental Thermal and Fluid Science, Vol.96, pp.329–346) shows that when severe liquid plug flow occurs, the pressure fluctuation propagates from downstream to upstream, so the upstream signal is not effectively utilized and cannot be well understood. The development of severe slug flow is well monitored

[0009] From the above summary, it can be found that although the above control method based on the signal fluctuation amplitude can eliminate the serious liquid plug flow after it is formed, it cannot prevent it from happening.

Images