Haiyuan Yao

Software Simulation for Making Severe Slugging Control Strategy in Deepwater Riser

As one aspect of flow assurance considerations, severe slugging control strategy in deepwater riser is related to the safety of production system, therefore it’s of great significance to the development of deepwater oil and gas field. This paper summarizes commonly used severe slugging control methods briefly, then takes certain deepwater oil and gas field as an example to introduce the method of software simulation for making severe slugging control strategy of deepwater riser. Firstly the model is built with basic information such as pipeline route, production profile and fluid composition. Data of typical years is used to simulate flowing conditions to determine whether it’s within slugging zone. To mitigate slugging conditions, choking, gas lift and choking& gas lift combined methods are chosen and simulated based on the oil and gas field characteristics, and according to the results gas lift is suggested as the best solution. Factors such as riser type, gas injection location, and flexible riser depth are analyzed for better gas lift efficiency. Finally hydrate formation risk related to severe slugging is analyzed and the slug catcher size is checked. Based on the introduced software simulation procedure, severe slugging control strategy is made, which will be valuable for deepwater flow assurance design and study.Copyright

Severe Slugging Control Methods Used in Offshore Multiphase Riser

Severe slugging control in offshore riser is an important aspect of flow assurance, if not well controlled, normal production could be interrupted and jeopardized. In this paper, firstly mitigation methods for severe slugging used in different oilfields are investigated, and their pros&cons, on-site applications and application scope are summarized. Then three severe slugging control methods adopted by CNOOC are introduced, respectively GLCC separation, auto choking, as well as gas lift. GLCC combined with the original slug catcher has solved the slug problem of the QK17-2 Oilfield, saving a lot of space and money. A set of online monitoring and auto-choking system was successfully installed and applied in WC Oilfield, contributing a lot to the production stability and production rate. The delicately designed gas lift annulus and gas injection system are expected to mitigate severe slugging and boost production of a west Africa deepwater oilfield co-explored by CNOOC. The introduction of these on-site cases will be of some value to for future design and analysis of severe slugging control for oil and gas fields.© 2013 ASME