Overview: Coiled Tubing Applications (June 2006)
Authors: Blount Curtis G. 
Published: February 2015

When it comes to coiled-tubing (CT) operations, job planning and design, tool selection, job execution, and full understanding of the well parameters are of utmost importance to achieving safe, environmentally sound, and effective operations. Fortunately, there is a wide variety of tools, techniques, and experiences to draw on when planning CT interventions. Job modeling and tubing-forces models are available from many sources. These computer programs have improved CT-operation effectiveness. Many grades, configurations, and material choices exist for CT strings that were not available only a few years ago (e.g., 120-ksi CT, corrosion-resistant-alloy CT, and external-upset CT). These CT materials can enable operations unheard of before their advent. The number of CT-specific downhole tools has increased exponentially over the last decade. The SPE eLibrary contains many new papers that address new tools and techniques used for increasingly complex intervention needs.

However, reaping the full benefits of new tools and techniques requires an increased understanding of the limitations of the new technology. For example, consider choosing a CT string to best fit the needs of a couple of job requirements: Modeling suggests that high-strength CT will provide 30% more available downhole pull for a fishing job than conventional CT material, but what are the ramifications on the CT life? Use of 16Cr tubing has been reported to be extremely effective in reducing CT damage when running in abrasive 13Cr-CT completions, but will standard HCl-inhibitor packages protect the investment in 16Cr CT during an acid job?

The tools to help choose the best equipment, plan the most efficient operation, and effectively execute the needed jobs are out there. Good-quality SPE papers on CT-specific tools and techniques are available online at www.spe.org. Forums and conferences, such as the SPE/ICoTA conference, are excellent venues for meeting professionals with similar interests for face-to-face discussions and to build knowledge-sharing networks.

The real challenge, it seems, is how to take advantage of available knowledge and achieve effective knowledge transfer. When the price of oil is down, few companies can afford the people to gather and disseminate best practices; they need to be out there generating revenue to stay afloat. And when the price of oil is up, few companies can find the personnel with time to gather and disseminate best practices throughout the company; they are too busy trying to recruit and train new employees.

Coiled Tubing Applications additional reading available at the SPE eLibrary: www.spe.org

SPE 100167 "Field Trial of QT-16Cr Chrome Coiled Tubing Used as a Work String on the North Slope, Alaska," by J.Y. Julian, BP plc, et al.

SPE 98045 "Safety Is No Accident," by M. Mahajan, SPE, BJ Services, et al.

SPE 100068 "Fatigue Integrity Analysis of Rotating Coiled Tubing," by S.M. Tipton, U. of Tulsa, et al.

IPTC 10308 "Underbalanced Coiled-Tubing-Drilling Practices in a Deep, Low-Pressure Gas Reservoir," by T. Kavanagh, SPE, Schlumberger, et al.

SPE 98044 "Successful Rescue of a Sunken Oil Well With Innovative Coiled-Tubing Solution," by M. Mahajan, SPE, BJ Services, et al.

SPE 100277 "Building Human Capital To Meet the Demands in Well Intervention," by M.G. Allcorn, SPE, Schlumberger, et al.