Scott Petrie, Adrilltech, UK, considers the development of continuous circulation systems and how the technology is being adapted in response to the pressures of the downturn.
RESPONSIVE R&D M
anaged pressure drilling (MPD) technology is now seen as a mature drilling technique, more of an accepted norm than the niche, novel technology it was 10 years ago. When MPD was developed, continuous circulation systems were perceived as a secondary, less capable offering. However, 15 years on and, in areas where cost considerations are paramount, continuous circulation has firmly established itself as a high value, lighter footprint solution that is quickly deployable to drill depleted formations for gas storage, geothermal or enhanced oil recovery (EOR) applications.
By diverting flow from the standpipe via a dedicated port in the side of the drill string and therefore isolating the top drive from the inside of the drill pipe, the pipe can sit in slips while circulation continues through the pipe/annulus and back to the active pit. Once the top drive is isolated and bled down, the next stand can be picked up and connected to the stump without stopping circulation. Flow is then re-established through the top drive and the hose used to circulate while the connection is made, is bled down and disconnected. The string is then picked up out of slips and rotation restarted before going back to the bottom and drilling ahead.
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