AnTech Ltd, an engineering design and manufacturing company serving the international upstream oil and gas industries, reported that interest in its coiled tubing drilling capabilities and equipment was at an all time high at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition 2009 in Houston, USA. Operators were keen to hear about AnTech’s successful field tests carried out last year. Of particular interest was an onshore well that AnTech drilled with its Colt bottom hole assembly for CTD in the Antrim shales of Michigan on behalf of an independent service company. The results were impressive, and drilling engineers from major operating companies were eager to learn more about how AnTech achieved them. The primary aim was to produce shale gas. This was accomplished by drilling a well with a hole diameter of 4 3/8in to a measured depth of 5090ft, and true vertical depth of 1750ft. A total distance of 1186ft was drilled, which commenced at 3858ft and stopped at 5037ft. At all times, real-time data while drilling was delivered to surface, providing engineers with the ability to accurately monitor position and conditions to control the direction. During the operation, AnTech used a series of drilling fluids which proved to be effective: initially brine, then 20% nitrogen followed by 40% nitrogen. This has been built on in further operations where the tool has been successfully tested with an air foam mix. The key to AnTech’s success lay in the thorough design work and preparation carried out. Its unique Orienter and wireline connectivity made it possible to drill underbalanced with precision in this gaseous environment.
