Overview: Coiled Tubing Applications (June 2007)
Authors: Blount Curtis G. 
Published: February 2015

After reviewing paper abstracts from many SPE venues for this last year, it became clear that coiled-tubing (CT) drilling is still generating much interest in the oil field. Yet with all the interest, few (perhaps with the exception the Canadians) are actually applying the technology in their wells. CT drilling is still striving for recognition, acceptance, and maybe just a little respect, as it has for longer than most would realize.
While researching material for a presentation several years ago, I found it surprising to discover just how old the concept of CT drilling really is. Most would guess CT-drilling technology dates back to the early to mid-1990s, and some of the CT-savvy Canadians often will move that date back to the early 1970s. However, the US patent office contains information disclosing the idea of using reeled conduits for "well boring" with a filing date of May 1926. While this early concept discussed the use of hose as a conduit, the idea of using rigid pipe for "well drilling" has a filed date of February 1948. Interestingly, these ideas were not just paper patents—the technology was applied in various forms starting in the mid-1930s. Over the ensuing years, CT-drilling technology was used both onshore and offshore. Discussions of the success in this early work include a phrase that still is used to describe some CT-drilling activities today: "It was a technical success."
While many will argue the merits of the use of CT-drilling equipment in an arena that often is considered the exclusive domain of rotary-drilling technology, fewer will question the value of CT to fill other completion voids previously performed by a drilling unit. One such example is CT fracturing, which gained rapid acceptance in many areas throughout the world as a viable tool to quickly, efficiently, and economically isolate and fracture numerous pay zones in well. And with the advent of high-angle and horizontal wells, many areas throughout the world use CT to perform tasks normally associated with slickline, wireline, or jointed-pipe techniques. Dozens of companies are providing new tools that enable CT to perform these needed functions economically, as documented in SPE papers.
Considering history, CT-drilling units will not displace rotary-drilling units. Neither will CT units make slickline, wireline, or snubbing units obsolete. However, if properly engineered and applied, CT's versatility allows it to perform a wide variety of services throughout the drilling, completion, and intervention arenas. This year's SPE papers validate this claim.
Coiled Tubing Applications additional reading available at the SPE eLibrary: www.spe.org
SPE 101065 "Near a Kilometer of Perforating Guns, in a 71/2-km, Extended-Reach Well—Coiled Tubing Shows Its Mettle in New Zealand" by P. Bartholomew, Shell Todd Oil Services, et al.
SPE 106907 "Successful Application of Underbalanced Coiled-Tubing Drilling in Horizontal Short-Radius Re-entry Well in Hassi Messaoud, Algeria" by Bachir Ben Amor, Sonatrach, et al.
SPE 102608 "3D Managed-Pressure Drilling Around a Salt Dome Using Coiled Tubing: A Case Study—Challenges and Solutions" by Abdul Mujeer Abdul Rehman, SPE, Maharashtra Institute of Technology
SPE 102661 "Fill Cleanout With Coiled Tubing in the Reverse Circulation Mode" by J. Li, BJ Services, et al.
SPE 107113 "Fatigue Life of Coiled Tubing With External Mechanical Damage" by T. Padron, BJ Services, et al.