Concept
Our patented pressure gradient and grease injection system is a new method to cap and seal off pressure in annulus during drilling, tripping and stripping.
- Several stationary sealing elements are installed in a serie, one above the other (in the illustration above, a standard setup with 4 sealing elements is shown).
- The total pressure is distributed across the total number of sealing elements in series by means of a gradient system.
- Each sealing element is testable and is continuously being monitored and logged for performance.
- The volume between each sealing element is filled with a controlled friction reducing fluid. This provides excellent gas sealing capabilities even with tong marks, voids etc on the drillpipe surface.
- Through each sealing element, a lubricant is injected directly into the sealing surface. This creates a cushion of lubricant between the sealing element and the drillpipe, and basically "lifts" the elastomers out from the drillpipe, still maintaining the sealing capability.
- If one sealing element fails, the others can be configured to take the full delta pressure and continue the operation.
The sealing elements are installed inside a seal cartridge, which is run and pulled by using a running tool, mounted on drill pipe. As a contingency plan, the cartridge can be run and pulled by the drillpipe tooljoint. The PCD consists of four main elements: PCD Unit, Control skid, Grease skid and Accumulator skid.
PCD
