Successful Qualification of Technology for Managed Pressure Drilling
Siem WIS AS, a company 60% owned by Siem Offshore, has announced a successful test and qualification of Siem WIS’ Pressure Control Device (PCD) technology together with Statoil’s control system for managed pressure drilling (MPD). The test was financed by Statoil and it has been run at IRIS’ (International Research Institute of Stavanger) test facilities at Ullrigg in Stavanger during the last two weeks. Highly qualified personnel from IRIS assisted in the implementation of the control system and during the tests. Ullrigg proved to be a very suitable facility to test both the PCD and the control system.
Together, Siem WIS’ PCD seal package and Statoil’s control system for MPD enable closed loop drilling operations, which represent a method to increase oil recovery and to increase drilling quality with reduced risk, both with respect to the reservoir and to emissions to the environment. The test included realistic drilling operations. Both the PCD and the control system are now qualified for commercial operation after meeting a predefined set of test criteria.
The control system for automatic MPD has been developed internally in Statoil the last two years. A mathematical model of the well is used to estimate the downhole pressure in real time and a nonlinear control algorithm adjusts a choke on the mud return flow to provide near constant bottom hole pressure at all times compensating for drill pipe motion and rotation and varying mud rates.
Siem WIS’ patented PCD is based on multiple stationary passive seals towards a dynamic drill pipe. Common rotating control heads normally holds one seal rotating with the drill pipe. In the PCD the total pressure in the well is distributed evenly across multiple seals, lowering the load on each seal and at the same time achieving redundancy. The pressure and temperature in each seal are monitored continuously. A sophisticated control system injects lubricant to every seal to lower friction and improve sealing lifetime. Siem WIS’ PCD will act as a primary well barrier element during closed loop drilling operations. The field applications for the PCD will be fixed installations and land operations.
Operations realistic for floating drilling rigs were also included in the test with good results for both Statoil’s control system and the PCD. As such it is now to build a Riser Pressure Control Device (RPCD), which will contribute to enable closed loop drilling operations from floating drilling rigs.
Per Espen Edvardsen, CEO of Siem WIS comments: "Siem WIS is pleased to finally have qualified the company’s first commercially available product based on the patented sealing technology. The qualification is an important step for further development and for the acceptance of the technology by the drilling industry."
