Jon Moreau, Jiskoot Ltd.
The development of new oil reserves, often containing heavy crude, is driving operators and suppliers to develop innovative solutions to optimize investment and production costs.
Jiskoot has developed a solution for the blending of heavy crude oil for Bergesen Worldwide Offshore. The company’s latest InSight crude oil blender will be installed on the 360,000-dwt FPSO,BW Enterprise, in Singapore later this year. The FPSO will operate on the Ku-Maloob-Zaap field in the Mexican sector of the Gulf of Mexico, with first oil scheduled for 1Q 2007.
The blender will provide capacity to blend the produced heavy 13° API crude oil with a lighter 21-35° API crude to optimize the value and specification of the blended product for export.
The system, which is designed to accurately blend a 16-21° API crude oil at up to 800,000 b/d, is a two-stream blender with online density measurement. The online measurement is used by the blender control system to continually optimize the quality of the final blended product.
To guarantee accuracy of the density measurement and ensure the final product is homogeneous, a JetMix system is used in the blend header. The Jetmix mixes across a wide range of flow rates with no pressure drop allowing the design of the blender to be optimized for a maximum pressure drop of less than 1.5 bars. This is also achieved by using ultrasonic flow meters and the careful selection of system components such as control valves.
The heart of the system is the Jiskoot InSight blend controller, which provides user-friendly control, measurement, and reporting of the entire blending process. The real-time, non-PLC control system provides all core blending control and measurement functions, and will be integrated with the FPSO’s Emerson DeltaV control system, allowing continuous condition monitoring by Emerson AMS.
The controller uses flow-weighted averaging and three-term PID control to ensure that the blended product is on specification at all times during the batch. It incorporates control algorithms to respond instantly to changes in process conditions or quality. The batch is continuously measured and the feedstocks adjusted to optimize quality and minimize “give-away.” The system is also designed to ensure consistent quality throughout the batch even during quality variations, feedstock starvation, loss of power, or the unlikely failure of a system component.
In the event of starvation of either of the two feed crude oils, the control system will automatically adjust the blend ratio to maintain control of the final product quality. If the system is unable to achieve this, it will shut-down, retaining the error so that it can be corrected when the system restarts.
In the unlikely event of a critical failure or system power-down on the FPSO, the blender will automatically shut-down and can be restarted with no loss of final product quality. The blender incorporates a facility to automatically increase the throughput of the system so that crude can be blended at the maximum available component rate to optimize the batch production time.•
