Technology from Europe:
Norway/Sweden

Field evaluation shows rotating separator may be an alternative to shale shakers

 Environmental requirements for operations on the Norwegian Continental Shelf (NCS), when drilling with oil-based drilling fluids, favor use of an enclosed system for solids control. Personnel working with shale shakers are often exposed to base oil mist and vapor at an unacceptable level.

Stricter environmental standards on the Norwegian Continental Shelf have prompted development of this enclosed system for solids control.

 A concept using rotating separators as an alternative to shale shakers was developed to reduce this exposure. Drilling fluid with cuttings from the mud line is fed into a slowly rotating separator that forces the cuttings to move over a large, effective screen area with screens of selected sizes. The drilling fluid is removed efficiently from the cuttings, while the area underneath the screen is slightly vacuumed.

 A working example of this system, dubbed Rotashake, was delivered by Altinex ASA and Rotashake AS to the Borgland Dolphin semisubmersible rig last year. The system was installed, and field tests commenced, using water-based and oil-based drilling fluids. During the tests, efficient but gentle separation of dried cuttings from the fluid was observed.

 Cuttings dryness was improved, even though 60% to 100% of the total cuttings load produced by the rig was directed through the rotating separator. Upon completion of these initial tests, the separator was brought onshore for further improvements. Based on the changes made, flow capacity was reportedly increased more than 100%. Further word on additional testing and/or commercial introduction of the system is expected to come shortly.