The Experimental Study and Real Time Forcast-Control Method of the Severe Slug Flow in Offshore Production Riser

With the development of the offshore oil and gas fields, multiphase transportation technology is becoming more and more important because it’s a cost-effective way for marginal and offshore fields. However, the complexity characteristics of the gas-oil-water multiphase flow, the hard offshore environmental conditions bring huge challenges to offshore platforms, subsea production systems, subsea pipelines and risers. Severe slugs in offshore risers, hydrate and wax block in subsea pipelines and flowlines will appear when the production system is shut down. In this paper, an experimental facility to simulate the riser slug flow is built, and the flow pattern of severe slug is given, the effects of the incline angles and viscosities on the formation of severe slugs in the riser is experimentally studied and analyzed using water-air, oil-air and water-oil and air. On this base, a cost effective real-time recognition technology of severe slug in the riser is present and its related automatic throttle control method has been validated by natural gas and crude oil with the 25m high riser system, which devotes to the future deepwater riser slug control system.