Optimized multi-stage ‘plug & perf’ in the Rockies
- Total depth 21,750 ft (6,629m)
- Max. deviation 90°
- Max. dogleg 17.85°/100 ft
- Bottom hole temp. 280°F (138°C)
- Bottom hole pressure 7,514 psi (51.8 MPa)
- Well head pressure 2,200 psi (15.2 MPa)
- Total distance tractored 146,608 ft (44,686m)
In order to save time on a 26 stage ‘plug & perf’ frac operation, an operator in the Rocky Mountains called on Welltec®’s e-line tractor-based conveyance solution. They needed to plug and perforate a well from max depth at 21,740 ft (6,626m) up to the upper perforations at 11,830 ft (3,605m) to get the well online as quickly as possible.
Due to casing issues the operator had previously installed a patch with an inner diameter of 3.6″ in a 4 1/2″, 11.6# casing string at 11,689 – 11,709 ft. (3,562-3,569m) in the horizontal liner of an oil well in the Bakken formation, North Dakota. Conventional methods were deemed unsuitable. Due to the restricted inner diameter of the patch, the operator could not pump the 4 1/2″ plug and was concerned that it would set prematurely or get pumped off causing an expensive fishing job.
Rig workover would have been too costly and time-consuming due to the number of zones, and a 2″ coiled tubing string would only be able to reach ~17,000 ft (~5,180m) omitting the lower 10 zones. Road weight restrictions complicated the logistics and it was doubtful that a rig or CT unit could make it to the well site. The operator had worked with Welltec on previous jobs in similar Bakken wells and had high confidence in the Well Tractor®, which made this solution an obvious choice.
Over the course of 14 days, 26 runs were made covering an impressive 146,608 ft (44,686m) with zero misruns and no lost time. Prior to the multi-stage operation, a run was made with three 6-ft guns.
Due to a dogleg of 17.85°/100 ft alert from WellSim, the first two runs were made with three and four 6-ft guns respectively, and the subsequent 24 runs were made with six 6-ft guns to minimize stage tractoring. The swift and nimble nature of the technology made it easy to overcome the logistical challenges and provided several HSE benefits to the operation, due to the low footprint, the reduced personnel requirements and less heavy lifting.
Welltec was able to successfully complete the operation on this well in 26 successful runs with no downtime or misruns.
As the well was already over the allocated Authority for Expenditure, the operator needed to get it on production swiftly without risking an expensive fishing job and consequent time and expense additions. The plug and perforation operation took 14 days, saving around one month compared to conventional rig workover.
This job went very smoothly. We were under the gun to get this well on production asap, and the well tractors enabled us to do this in a timely manner.