Yard and Field Testing of a Tapered OD Coiled-Tubing System

摘要

The concept of a tapered outside diameter coiled tubingsystem (TODCTS) was first presented in 2004.2004.1 This paperlaid out the basic requirements for a TODCT system and theadvantages of the TODCTS in ultra-deep wells (30,000-ftrange). The TODCT system includes:? A modified injector that can handle more than onediameter of tubing and maintain a constant grip onthe tubing throughout the length of the TODCTstring.? A “transition tube” that allows sections of tubingwith different Ods to be joined together.? Well-pressure control equipment (I.e., blowoutpreventer and stripper) that has the capability to gripand seal more than one diameter of tubing and canalso grip and seal the transition tube.? An operator control house that allows remote controlof the stripper elements and injector gripper elementsto open or close to different diameters of tubing whilestill maintaining control of well pressures inside thewellbore and grip on the tubing.This paper continues the work that was started previously.A review of the yard testing completed on the equipment isincluded along with a subsequent field trial done onshore insouth Texas. The end result is a tested and qualified TODCTsystem capable of safely running tubing strings into ultra-deepwells.