The Efficiency of Coiled Tubing Technology

Coiled tubing technology dates back to World War II when in 1944 British engineers were tasked with developing long continuous lengths of pipeline that had to stretch from England to mainland Europe. Dubbed PLUTO, for Pipelines Under The Ocean, the project supplied the Allied armies' European advances after the D-Day landings.

These early prototypes of the technology, which involved the manufacture and spooling of the pipeline tubing, formed the basis of what developed into the oil and gas industry coiled tubing technology commonly used today.

Early experiments were with butt welded lengths of tubing originally, but found it to be too problematic. Today, continuously milled steel tubing is used, which has no joined parts, to provide the flexibility required.

The development of this tubing technology in the oil industry dates back to the early years of the 1960s when it was first used in the USA. The California Oil Company, in conjunction with Bowen Tools, made and created a coiled tubing device to successfully clean and wash out sand that was restricting the oil flow in the wells. There are many benefits over the rigid piping that has to be inserted in sections as this is a slow process with many potential hazards. The tubing can be inserted at speed and can be reused many times throughout its lifetime. This has a dramatic financial implication, making it considerably less expensive to use.

The technology is extensively used for regular maintenance work inside wells. Maintenance applications generally account for 75% of its use in the oil industry today. In shallow wells in particular, advances now mean that there is an increased use for coiled tubing in well drilling applications in a process known as ultra-slim completion.

Depending on the well bore width and other factors, the efficiency of coiled tubing technology can mean that the tubing can be unwound and fed into a well at the surprisingly rapid rate of up to 30 metres every minute. However, there are often obstructions, which slow this rate down, sometimes considerably so. An average insertion rate may therefore be closer to 20 metres a minute. The removal of coiled tubing, on the other hand, is a much faster operation as there can be no impediments to slow the operation down.

The engineers who work in this field are generally highly skilled individuals. It is usually a skill that is taken up by those who have a thorough understanding of the oil industry engineering practices in general. Often individuals work beside experts for some time learning the efficiency of coiled tubing technology to gain the expertise they require.

This particular tubing does have its limitations, however. At depths of more than around 6,000 feet it cannot be used, though this limitation may be overcome in time. Wells that go deeper than this require other, more traditional, methods of drilling. If the well bore size is too narrow, then coiled tubes may not be possible either.

The efficiency of this technology has offered the oil and gas industry a tremendous benefit in terms of usefulness and cost savings. This, of course, can be passed on to the man in the street, so to speak, by slowing down the inevitability of rising costs in fuel.