The RDM is based on the use of a Dual Drill String where the drilling fluid flows to the bit via the drill string annulus, and the return flow to surface is through an inner string.

The components

• The Dual Drill String (DDS) is a closed loop flow circulation system. Cuttings are transported to the surface by drilling fluid travelling up the central pipe of the dual string, leaving the wellbore annulus free of cuttings.
• The Top Drive Adapter (TDA) is a dual conduit swivel that allows rotation of the drill string with the top drive. The TDA  route the discharge drilling fluid from the top drive to the DDS annulus and the  return flow is taken of the TDA housing. 
• The Dual Float Valve (DFV) contains double barriers on both channels and facilitates controlled pressure drilling and pressureless pipe connections. Two or more of the DFV can be mounted in series in the DDS for redundancy. 
• The Flow Control Unit (FCU) is a control valve arrangement where all the active drilling fluid is routed through. The purpose is to assure constant downhole pressure during drilling and pipe connection. The unit is equipped with pressure and flow sensors both on the drilling fluid inlet and return lines. The Reelwell control panel is fully integrated with the well control and monitoring system of the drilling facility. 

How it works

 RDM differs from conventional drilling in the circulation flow path of the drilling fluid. For conventional drilling the fluid returns up wellbore annulus, whereas in RDM the drilling fluid returns to surface through the inner pipe of the DDS. RDM is based on pumping the drilling fluid into the DDS annulus via the TDA and down to the DFV at the top of the conventional Bottom Hole Assembly (BHA). From the DFV the cuttings are transported back to surface inside the inner string, so that the hole remains clean at all times.

The Reelwell Drilling Method wins the OTC Spotlight Award 2010.

Key features

HOLE CLEANING  The cuttings are removed above the BHA leaving a clean hole. PRESSURE CONTROL A small active fluid system volume reduces ECD spikes and reduces the stress on the formation. The system uses MPD.

More information:

> Watch a 3.5 min video on the basics of the technology in the Archive section. 
> To take a look at images of the different components, go to the RDM operations section.
> Read scientific and news articles published on the technology in our Archive section, Publications and News Articles