Reverse circulation has always been viewed with some level of suspicion and reverse circulation with coiled tubing has often been avoided at all costs. Yet, results of over 1600 CT operations involving reverse circulating in Alaska's oil fields, with just a handful of failures, has proven reverse circulation to be a reliable procedure for a specific range of solids removal that is extremely effective in removing sand fill from wells with very large tubulars and in high deviations. Results from North Sea, Colombia, California and the US GoM are also included. This paper presents the basics of reverse circulation designed specifically for coiled tubing; including necessary surface equipment, BHA nozzle design, pump requirements, fluid rates, and procedures to reduce the potential for problems. The procedures and job overviews contained here were contributed during an ICOTA panel discussion on reverse circulating, held September 18, 2003, in Houston, TX.

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