AnTech Ltd has completed two successful drilling operations with the COLT™, a coiled tubing drilling (CTD) bottom hole assembly (BHA) designed for the re-entry and thru-tubing markets. The COLT withstood the rigors of the punishing vibration produced when drilling with aerated fluids, while responding promptly to changes in direction and speed.

AnTech carried out the operations using the COLT on two wells in shale gas reservoirs in the northeast of the United States. The primary aim was assess how simple the tool was to use, control and steer. The secondary aim was to gauge its reliability and ability to drill with gaseous drilling fluids in high vibration environments.

First Field Test: COLT Successfully Re-drills Reservoir Section Following design and testing in the lab at AnTech’s headquarters in Exeter, England, the COLT was put through its first field test in a well. The well had originally been drilled conventionally with jointed pipe, but well problems meant that casing could not be run to total depth (TD). To remedy this, AnTech was offered the opportunity to re-drill the reservoir section, which would require drilling out a cement plug at the bottom of the casing, creating a new well trajectory, and drilling a new horizontal section.

In temperatures as low as -20°C (-4°F), the AnTech team gathered at the wellsite. Equipment was assembled, including a rig with 2-3/8” diameter coil with e-line, surface infrastructure and fluid tanks, a workshop trailer and a crane. After carrying out preliminary procedures, calibrating and assembling the equipment, the team lowered the tool into the hole with the crane. To ensure that the BHA would be accurately aligned, AnTech designed custom alignment tools and tool handling equipment with hydraulically-powered pistons to control deployment. By using the crane, the system was set up and deployed in just over two hours.

Tags: AnTech Limited