Abstract: A pre-alarming method, a control method, and a control system for a harmful flow pattern in an oil and gas pipeline-riser system are provided. Support vector machines are trained. Through at least three pressure difference signals on the pipeline-riser system, an overall flow pattern in the pipeline-riser system is continuously and rapidly identified. Depending on monitoring on formation of a long liquid slug in a seabed pipeline and a quick response of the mean value of each pressure difference signal on a flow rate change, pre-alarming for a liquid slug caused by different mechanisms is realized, and liquid slug formation positions respectively of seabed pipeline and riser bottom are correspondingly pre-alarmed; after a pre-alarm is issued, there is enough time for a control device to respond, so as to avoid formation of the harmful flow pattern or damages caused by the harmful flow pattern.

Abstract: A pre-alarming method, a control method, and a control system for a harmful flow pattern in an oil and gas pipeline-riser system are provided. Support vector machines are trained. Through at least three pressure difference signals on the pipeline-riser system, an overall flow pattern in the pipeline-riser system is continuously and rapidly identified. Depending on monitoring on formation of a long liquid slug in a seabed pipeline and a quick response of the mean value of each pressure difference signal on a flow rate change, pre-alarming for a liquid slug caused by different mechanisms is realized, and liquid slug formation positions respectively of seabed pipeline and riser bottom are correspondingly pre-alarmed; after a pre-alarm is issued, there is enough time for a control device to respond, so as to avoid formation of the harmful flow pattern or damages caused by the harmful flow pattern.