Abstract
In November of 1996, Apache Canada drilled a gas well with coiled tubing in the Harmatten Field northwest of Calgary. A a true vertical depth of 2572 metres, the well was the deepest successful coiled tubing horizontal well in Canada to date. The reservoir was underpressured with a pressure gradient of 6.5 kPa per metre. The well was drilled and cased to 90 degrees with conventional rotary drilling operations, after which a coiled tubing unit was rigged on and the horizontal section of the well drilled underbalanced. A total of 368 metres of underbalanced 120.7 mm wellbore was drilled, which included two open hole sidetracks. Gas production rates during drilling were in the range of 5-6 MMSCFD, and reservoir gas contained approximately 0.5% hydrogen sulfide.
This paper will describe the equipment and associated drilling performance for this operation, and will elaborate on open hole sidetracking capabilities. Drag modeling, tubing lockup, and potential lateral extent for drilling at these depths will also be assessed.
