Active Mudline Pumping, Design, Testing and Future Possiblities in Rig Design

Authors:  Young Wan Hong and Robert van Kuilenburg, Noble Drilling Services, Inc.

The drilling industry is continuously improving drilling efficiency and safety.  Precise control of the downhole pressures and knowledge of fluid flows is an essential element in any drilling improvement project.  To obtain real time fluid flow datea in drilling operations Coriolis flow meters are more and more used.  However Coriolis flow meters are expensive, prone to be blocked by cuttings and handle multiphase and gas  entrained fluids poorly.

To mitigate the problems associated with Coriolis flow meters, Noble Drilling and selected 3rd party vendors teamed up to design and test a test skid to prove the performance of a surface based active mud line pumping system.  Active mud pumping systems could be a key component for future drilling rig designs and improve performance of current rig designs.

The active mud line pumping system is a pumping system to transfer drilling mud laden with cuttings using pumps from teh gumbo box to the shakers.  This allows detecting well bore problems such as kicks and loss of circulation with minimum time delay.  By adding we3ight sensors, fluid den tsity can be determined and if installed in the active mud tanks full flow-in / flow out data can be obtained.  Active mud line pumping systems do not rely on gravity driven flow for moving fluid.  This allows more efficient rig designs with improved safety features as well.

A key design feature of the active mud line pumping system is that it uses components that are already used on drilling rigs.  This will facilitate efficient operation and maintenance by normal rig crews.

The testing shows that by using Tesla pumps it is possible to transfer heavy cuttings laden drilling fluids accurately without degradation of the cuttings.  Valuable insights were gained at start/stop performance and flow measurements.  Future tesing will focus on improving the kick detection control loops and extending the modeling of the systems for future rig designs.