New String Deployment Concept Extends Operational Limits for Megareach Interventions

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22577, “Extending the Operational Limits To Target Megareach Interventions With Coiled Tubing: A Study of the First 40,000-ft-Long CT String Deployment Using Uniquely Engineered Energy Transportation Solutions,” by Karan Kaul, Nicolas Dupouy, and Jose Jimenez, Halliburton, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. An operator requiring an offshore coiled tubing (CT) intervention into 40,000-ft-deep wells from artificial islands of the United Arab Emirates encountered challenging crane and transportation limitations to lift a 2⅜-in. CT reel weighing approximately 200,000 lbm. This, combined with a desire to improve operational efficiency in moving from well to well and eliminating large mechanical lifts, led to the design of a custom-engineered transportation solution for the large-diameter, heavy CT spool. Introduction CT and its associated setups are in high demand for wellbore intervention to perform operations such as valve or sleeve shifting, pinpoint stimulation with custom chemistry, milling, fishing, wellbore diagnostics using fiber optics, and drilling with different downhole tools. These tasks become even more challenging when difficulties associated with extended-reach maximum-reservoir-contact reservoirs are considered. While the term “extended-reach” refers to wells for which the measured depth (MD) is greater than twice the true vertical depth (TVD), the term “megareach” refers to wells for which the MD is greater than three times the TVD. A CT string is a continuous string of pipe manufactured from a specific grade of material determined by the downhole application for which it is intended. It is coiled over a drum (referred to in the paper as a spool) with more than 25 full layers around the bed wrap and has a high amount of energy stored in it because of the residual bending of the CT material. Although the string is secured at the end with an industry-specific clamp, close monitoring is required to avoid loosening from vibrations caused during transportation. After storing the CT pipe on the spool, the spool usually is shipped and transported from the shore jetty to the artificial island jetty using a conventional vessel. It is then offloaded, lifted, and secured onto a CT drive reel using a regular crane ready for wellsite operations (Fig. 1).