Promising to challenge the limitations of conventional drilling, Reelwell has introduced a new drilling methodology known simply as the Reelwell Drilling Method (RDM). The method promises increased hydrocarbon recovery and reduced environmental impact while drilling some of the most challenging wells in the world.
RDM is based on a concentric dual drillstring, closed-circulation system in which drill fluid and cuttings are brought to the surface through the center pipe, leaving the wellbore annulus free of cuttings. For increased safety, a dual float valve and piston secure fulltime pressure control during drilling and making pipe connections.
Schematic showing different components of the RDM in a well.
The system reportedly provides for increased safety by avoiding any choking at the surface while drilling, and formation damage is reduced due to the heightened pressure control, which avoids loss of annular fluid and downhole pressure peaks. Environmental benefits are realized through low power consumption, and a relatively small volume of active drilling fluid is required.
The company states that the RDM can be used for most drilling scenarios, but its true benefits are realized in the following situations:
Managed pressure drilling, in which the tool's light drill fluid, closed-loop fluid circulation, and pressure control allow for control of well pressure to be equal to or slightly higher than the formation pressure—a technique used primarily for mature reservoirs where pressure is low due to depletion.
Extended-reach drilling, a type of directional drilling for long horizontal wells. The new method allows for improved hole cleaning while drilling and the piston provides better management of weight on bit through hydraulic pressure, both of which serve to potentially increase the reach of horizontal drilling.
Deepwater drilling, aided by the new method's feature of confining all circulation in the dual drillstring. The new method may push existing deepwater limits through riser less drilling.
In March 2009 a pilot well was drilled using RDM at the Ullrigg Drilling and Well Center at the International Research Institute of Stavanger. With the main objective to demonstrate the RDM functionality with conventional downhole drilling tools, an 8 ½-in. openhole section was drilled using a 4 ¾-in. motor. The trial achieved excellent rate of penetration, with all conventional tools working well with the RDM. For its part, the RDM exhibited excellent hole cleaning.
The offshore E&P industry has taken notice of the innovation and potential positive impact of the RDM. Reelwell was awarded a Spotlight on New Technology Award by organizers of the May 2009 Offshore Technology Conference in Houston. The technology and application of the technique successfully met the five criteria for a Spotlight Award: the technology should be new, innovative, proven, used in a broad range of applications, and have a significant impact on the industry.
