Statistics of Coiled-Tubing operation Failure based on Human Error and Solution

A study of root causes for coiled tubing failures over a five-year period indicates that a substantial percentage of incidents were attributed to human error. This type of incident involves the application ofexcessive over pull resulting in pipe necking or complete parting of the pipe due to tensile failure.Similarly, too much snubbing force will cause pipe buckling and compressive failure. Both have the undesirable result of a damaged CT string at best or a compromised well control security -at worst. Using a properly trained and fully competent crew can minimize such events. However, the arduous and stressfillednature of live well CT operations will limit the elimination of this human element. In Coiled tubing recent operation, several successful initiatives have been introduced to mitigate the riskof coiled tubing failure while performing interventions in oil and gas wells. Through the use of reasonably accurate computer modeling, the industry has seen a marked reduction in the number of pipe failures associated with material fatigue due to the constant plastic deformation occurring during pipe tripping operations. Similarly, the judicious practice of employing off-line pipe quality inspection tools, as well asthe availability of real-time monitoring of pipe geometry through a variety of devices has contributed to amore predictable and more favorable pipe performance.An effective means for eliminating the possibility of human error becoming a factor in conditions that could result in a pipe failure during normal CT operations presented in this paper. Through the incorporation of a specialized system in our software, ORIONTM in the coiled tubing unit controls, a safety device is put in place to provide a shutdown featurewhen specific job designed set points are exceeded.

Keywords:

Catastrophic operational failure , Major operational failure , Serious operational failure