Top-Mounted Compensator | SLB

Top-Mounted Compensator

Large range of motion for harsh environments

Top-mounted compensator system

Cameron top-mounted compensator (TMC) systems are used to compensate for the relative movement between the drilling vessel and seabed. The large range of motion for our motion compensation equipment enables floaters to operate in some of the harshest environments. The compensator is highly accurate, with a 25-ft stroke and optional active cylinder and is supplied with an accumulator, valve block skids, air pressure vessels (APVs), control system, and optional air compressors.

The top mounting of the compensation system allows hook load variations to be addressed directly to the crown block, minimizing weight on bit (WOB) fluctuations. The careful placement of the compensation cylinders enables all standard top drives to be lifted between them, which means no reduction in the lifting height of the traveling assembly.


  • Top-mounted installation reduces WOB fluctuations
  • Cylinder placement designed to allow standard top drives to be lifted between compensation cylinders
  • Lower overall compensator weight due to modern vertical cylinder arrangement
  • Compensator lockable in any position
  • High static force rating
  • Unit ready for easy installation on top of the derrick at delivery
  • Active heave compensator easily added
  • Low-friction seals in the cylinders and accumulator
  • Reduced effect of compression/decompression of the air volume due to cylinder movements, resulting from geometry of the rocker arms in combination with how the wire is reeved over the guide sheaves
  • Flow shutoff valve to protect the system against uncontrolled movement in the event of a drillstring failure
  • Position measuring system for the crown block
  • Only hard piping between the main components (i.e., no flexible hoses)
  • Customized programmable logic controller (PLC) software, providing simple and natural operator controls from a single point
Top-mounted compensator system