Extended Reach Lateral Mill Out


In 2022, a major Oil & Gas producer was developing plans to drill extended horizontal wells in the high pressure Duvernay Shale formation which would exceed the capacity of Coil’s reach on this well. Piston, having a reputation for its successful millout campaigns, was engaged by the producer to develop a program to millout the frac plugs to the toe with jointed pipe on a 3 well pad. Piston TD’d Well #1 at 8,200mMD (4,800m lateral) Well #2 was TD’d at 8,500mMD (5,100m lateral) which surpassed our previous record in Canada the year before of 8,400mMD and the 3rd  well set the still standing Canadian Record for Longest Well completed at 8,700mMD (5,300m lateral).


  1. The process began with modeling the optimum drill string for the job with Piston’s custom workstring. Calculations showed that, without rotating, the string would helically lock up at about 5,500m.
  2. A tapered string was selected to manage tension and torque while rotating the string 100-110 RPM against an expected friction factor of 0.20.
  3. Three pipe weights and two different OD of pipe configured the string. All sections had high-torque PH6 pressure rated connections.
  4. Modeling results showed 4,800-5,800 ft-lbs of torque would be required to rotate the string at 100 RPM, which would allow the toe to be reached with 20 kdaN of surface tension. The modeling showed that we would be under the allowable operational torque and tensile limits.
  5. After completing the CWOP meeting Piston readied Rig 9 along with Piston owned customizable workstring, all profile nipples and crossovers required to complete the job. Coordinating with the customers preferred thru tubing provider the BHA was configured.


  1. While reaming Piston crews were able to maintain 80m per hour well past 7,000m. While tripping in and out of the hole Piston maintained 50 joints per hour even pulling from TD.
  2. Approaching 8,500m, the rig was performing at 95RPM with 5,000 ft-lbs and 22 kdaN in the slips. Dissolvable plugs did result in some longer than anticipated drill times compared to composite plugs. Milling stopped at 8,700m; just short of the target depth of 8,900m due to an unknown obstruction near the toe of the well. After numerous bit changes we were unable to mill through the obstruction leaving the customer to cease milling operation.


Piston’s rigs are unique and loaded with proprietary efficiencies; learnings from the company’s 20+ successful years in the snubbing business. Rig 9 in particular, with a 15K BOP and 285,000lb hoist capacity (and 169,000lbs of snub force), has big-rig power but can still be rigged up with only 2 picks, swing in a single lift and trip pipe over 60 jts/hr in 2-leg mode.


  • Fully Guided Jack
  • Integrated Gin Pole up to 80’ x 10,000 lbs for large BHA’s or double stands
  • 150 RPM, 10,000 ft-lb rotary w HALO Swivel
  • Integrated Torque Track
  • Dual 15K Pumps w 40m3 Mud/Mix Tank
  • Multiple redundancies in well control, wellhead stability, torque and pumping abilities


As a result of milling with jointed pipe the customer was able to reach a length that previously was unattainable. The customer was able to exploit more of the reservoir with a single well and save costs on new drills.