Equipment: Ditch Witch® RS7, Ditch Witch® JT4020, STRAIGHTLINE® RockEye Air Hammer 5.0 coupled with an Sullair 1150CFM x 350 psi compressor.
Location: Bartlesville, OK
The Challenge:T.C. Underground, Inc. was awarded an exceptionally challenging bore, to install a 4” continuous gas line, just south of Bartlesville, OK, along U.S. 75 Highway. The bore was to cross the Caney River and environmental concerns were present, as the river bed was not to be disturbed. In addition to the depth of the bore, existing utility lines and an incredibly tight easement added to the complexity of the shot.
The bore was originally attempted with a Ditch Witch® RS7, however, the attached tool was lost underground. The call was put out to StraightLine® Lead Field Engineer, Ron Becker and a JT4020 was outfitted with a 5.0 StraightLine® RockEye Air Hammer. “We had to launch at a minus 30 percent to enter the lime stone before we got to the water,” stated Ron Becker. Due to the sand that was in the first 200’ of the bore it required a heavy bentonite mix to maintain the annular velocity and keep the cuttings moving. Straightline’s use of drilling mud and foam made this bore possible through the varying soil conditions.
Overcoming the sand and limestone at 335’, the bore required 45’ of elevation change to hit the exit pit at 420’. Achieving a rate of eight to nine percent gain per each 15’ of rod, the bore exited on target and met the tight easement requirements.
Owner/Operator Tom Chism stated, “Most bores, the pilot hole and the back ream take about the same amount of time…. With the StraightLine® RockEye Air Hammer system, we completed the pilot hole three times faster than we completed the pull back. I was most impressed with the speed of the RockEye. It went through very hard rock with impressive speed and precision.”