Coiled-tubing drilling gets big

Unnoticed by most except the specialist contractors, over the past three years there has been a four-fold increase in the worldwide annual total of wells drilled with coiled-tubing equipment. The new technology – troubled by equipment problems in its early days – is still aimed at niche applications, but it has grown into a big business, Martin Quinlan writes

DRILLING WELLS with coiled-tubing (CT) equipment – in which the drillbit and its motor are carried on the end of a flexible steel tube, fed out from a large reel – can be an attractive alternative to the industry's standard, the rotary drilling rig. Wells can be drilled quicker with CT; the rig can be assembled more quickly and takes up a smaller footprint at the drilling site; and the operation is relatively quiet, making CT preferable for drilling near built-up areas. Drilling with a rotary rig – using a drillstring made up of heavy pipe sections, nearly 32 feet (9.75 metres) long – is laborious, noisy, dirty and dangerous work. The rotary's drillstring has to be taken apart when the drill