Rock In Colorado Challenges HDD Contractors

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Special to Pipeline News

When problems threatened a segment of the eight-mile, Edwards to Meadow Mountain natural gas pipeline upgrade in Colorado, Fugal Pipeline Project Manager, Brady Hansen had to make a decision.  The 2,011-foot segment of the 16-inch diameter line through the Eagle-Vail business district was to be installed using horizontal directional drilling (HDD) to avoid road closures and minimize disruption of local business.  After multiple attempts without a completed pilot hole the situation was tense.    Business owners had been told there would be little disruption and given a construction schedule.  As the schedule deadline passed with no progress, doubts about a successful HDD installation grew and the financial consequences of an open cut installation that would close traffic to the Eagle-Vail business district created worries. 
  In the HDD business, nothing is guaranteed, but these conditions were extreme. A call was made to Jim Brotherton of Brotherton Pipeline.
  Brotherton was familiar with the project and had submitted a proposal a few months earlier. However, scheduling had prevented his company from becoming involved in the project. 
  Fortunately, the call came just as Brotherton Pipeline’s HDD team was demobilizing from another project. Based out of Gold Hill, OR, the Brotherton name is synonymous with pipeline construction in the west and northwest.  Jim Brotherton, president, has over 30 years of experience and is a pioneer in the HDD industry.  
  He is also well aware of the boulders and cobble, inherent to the area, that can create a worst case scenario for an HDD contractor.  
  Hansen had confidence he was changing more than just equipment when he engaged Brotherton Pipeline as the new HDD contractor for the project. 
  As the crew began rigging up the 550,000-lb Ditch Witch rig, staffed for 24 hour operations, Jim was well aware that area business owners and their employees were keeping a close watch on the project’s progress and that much of the earlier confidence in the HDD had  waned when the previous contractor attempted to complete the job.  
  Jim met with the group, listened to their concerns regarding a possible road closure, and explained his plan, including the fact that this was not going to be a routine drill. He did stress, however, that the circumstances dictated a need for immediate success.   
  “There was boulders the size of trucks,” he said. “Drilling through these conditions doesn’t get easier but with experience we continue to get better. The pilot hole isn’t just half the battle because there is no partial victory.  You have to ream the hole to size and pull in the product line or it is a failure.  You always need a plan but must also react, matching the conditions encountered.  Knowing what not to do is just as important as knowing what to do.  It’s not a case where more power is needed, anyone can bring in a bigger rig.  HDD requires finesse and these conditions magnify that need.”  
  With Jim’s most experienced crew and guidance services provided by Chris Hale of Horizontal Technology Inc., the work began and the pilot bit drilled its way through the cobble and boulders.  The plan was to get through the trouble area that had been encountered at the entry and then transition into solid rock before leveling off and then direct the bit back up to the exit with as few trips as possible. 
  At about 60-feet deep the formation changed and the driller started his initial build section coinciding with the original plan to level out at a depth of 150-feet.  A complicated project became more so on joint 13 when 100% of returns were lost.  
  Israel Brotherton had the controls of the HDD on the day shift and Matt Brotherton handled the night shift. Jim made the decision to continue with the same bit and assembly used to work through the boulders and not trip out for the down-hole motor, on site and ready.  Through rotation and with skilled hands on the controls, working the bit, pushing ahead at the right times, both Matt and Israel were able to obtain the needed build rates to stay on the designed path.  This “rock and steer” method had been developed and utilized successfully on previous projects.  The plan was to continue advancing the pilot hole as long as the conditions allowed.  
  A motor may have drilled faster, but tripping out, then back in, was risky and would require an increased GPM.  Lost returns had already slowed production as the crew continually fought to refill water tanks and mix mud.
  Patience and technique resulted in steady progress with no setbacks.  As the pilot hole began its build toward the exit, penetration slowed.  The decision was made to trip and change bits.  After consideration, Jim decided to return to the bottom with the new bit, without the addition of a motor.  Again, the choice was the right one, as the driller worked the new bit through the trouble and back into the original pilot hole until reaching bottom.  The same technique was continued until cobble and boulders were encountered at the exit side, sooner and deeper than expected.  This discovery would increase the difficulty, as well as the risk, during the reaming process.  The pilot bit was on line and just short of exit when a wire-line short interrupted communications with the magnetic steering tool.  The last joint was slowly rotated into the pre-constructed exit pit confirming the accuracy of the DataTraX guidance system being used. 
  A 24-inch, TCI RockReamer was attached at the exit and pulled back towards the rig.  Jim watched and listened as the tool worked its way down through the soil and boulders.  Unsure and worried by what he was seeing and hearing, he ordered the tool pushed back to surface.  After studying the situation, he sent Matt and Israel back to the yard with a plan.  Back-reaming would involve more Brotherton tricks of the trade.  
  “There was too much space for cobble and rock to slide between the cutters,” Jim explained. “This buildup of cuttings and loose rock could damage the tool and drill string, while leaving us with an inferior hole that could cause trouble during pullback. I needed this tool to grind everything and let nothing slide by.”
  Matt and Israel worked through the night.  They used a ¾-inch wall, 18-inch diameter casing to craft a protective shield that was placed around the tool, with very close tolerances between cutters.  The fitted armor left no room for anything to slide between the cutters and forced anything loose in the hole to stay ahead of the RockReamer’s TCI cutters.  At sunup the next morning, the Brotherton’s customized tool was returned to the rig site, ready to resume reaming operations.
  “Rotating the reamer into the hole was still rough but it was different this time,” Jim explained. “You could hear the rock being destroyed as the tool moved ahead.  Loose cobble and pieces of boulder were chewed up as the RockReamer closed in, trapping fragments between itself and the formation ahead, clearing a 24-inch path all the way down and into the solid rock.  We had the best hole possible through the trouble zone and needed to complete the 24-inch pass without tripping.  I knew the RockReamer cutters could hold up with the protection of our turtle shell.”
  Continuing, Jim noted that reaming was steady through the rock at a pace of four or 5 joints a shift. Circulation was never regained and the source of available water changed a couple times, slowing the process.  The progress continued, placing just under 280 reaming hours on the 24-inch cutter set.  The ream, back up through the entry side cobble and boulders, continued without incident, with the fabricated shield working just as it had through the exit side.  The pilot hole and reaming phase were now complete but the hour of reckoning was at hand.  Nothing mattered without a successful pullback of the product line.  
  Another R8 RockReamer was fitted with two-inch TCI cutters and a Brotherton-made shield was placed ahead of the swivel, pull-head and the 16-inch product line.
  Jim pointed out that the only way this would work is if the boulders and cobble had been ground-up and cleared.  If any of it had slipped past the RockReamer or dropped into the hole, it could render the final task impossible. 
  He said, “About 7:30 a.m. the pull-head was ready and the rig applied tension to the drill string to pull the 16-inch product line into the hole.  One joint in and hearts stopped.  A large boulder slipped!  You could hear it hit steal and the torque spiked.”
  Jim placed his hand on the drill string asking for slow rotation, before making the call to continue.  “You could feel it in the rotation,” he said, “As pull was applied, you could hear it grinding away as the cutters chewed and crushed the rock.  We decided to keep going. The chatter lessened, then ceased, as the line continued forward through the boulders and into the solid rock.”  
  Just one weld and 12-hours later, business owners stood with the crew as they witnessed the 16-inch product line extend into the entry pit.
  The pull back was successful for Brotherton, but even more so for the business owners with whom Jim and his crew had developed a solid relationship.
  The Eagle-Vail business park had remained open without interruption.  Brotherton Pipeline had completed the project with a single pilot hole attempt and a single reaming pass despite treacherous conditions and 100% lost circulation.  While Fugal had utilized HDD to keep their promise, Brotherton Pipeline had used experience and innovation to successfully complete another difficult project.