Schlumberger

Performance Report: MEGADRIL Drills the Longest Extended-Reach Well in North America

Challenge: The operator programmed an extended reach well that posed a number of technical demands, including an extremely long 27,274 ft ( 8,301 m) 9 ⅝-in. liner in the 12 ¼-in. hole. In addition, the well was designed with more than 6.3 miles (10.14 km) of lateral offset, which was restricted by extremely limited deck space and pit capacity on the rig.

Solution: M-I SWACO recommended the MEGADRIL oil-base drilling fluid system with MEGAMUL, a single-drum emulsifier/wetting agent package that simplifies maintenance, logistics, and reduces inventory on location. MEGADRIL is engineered to provide a stable emulsion, inherent low HTHP filtrate and lower rheological properties than a traditional invert‐emulsion system, which combines to lower pump pressure and ECDs. Consequently, MEGADRIL is the preferred system when tight emulsions and thinner fluids are required. The system already had been proven to be effective over a wide range of temperatures, densities and oil-water ratios in over two hundred vertical and deviated wells.

Result:

  • Successfully drilled the longest extended well in North America
  • World’s longest extended-reach well drilled from an offshore fixed platform drilling rig
  • Extremely fast drilling process and high quality wellbore saved 90 days drilling time
  • Reduced well AFE by 20%
  • Zero environmental incidents

Well Information
Location Offshore, U.S.
Date October 2009 - January 2010
Total depth over 37,000 ft (11,277 m)
Intervals drilled over 26,800 ft (8,168 m) of 12 ¼-in. hole
Intervals drilled over 2,200 ft (670 m) of 8 ½-in. hole (to TD)
Well type Extended-Reach 0° – 88° – 45° (at TD)
Disposal method CRI

In this area, the operator relies on rig site mud engineering consultants. Accordingly, M-I SWACO worked very closely with the operator’s drilling team and the mud engineering consultants for the entire duration of the project. Mud samples were shipped from the rig site to M-I SWACO regional technical support lab every two to three days for HTHP rheology testing. Afterwards, M-I SWACO Technical Services in Houston used the results to better calibrate the VIRTUAL HYDRAULICS wellbore simulator to accurately monitor the downhole cleaning, ECD’s and ESD’s.

Based on the very frequent HTHP rheology tests and the VIRTUAL HYDRAULICS hole cleaning simulations, the rheological properties of the fluid were lowered to the point of providing very good ECD and SPP without compromising the cuttings carrying capacity. The high quality wellbore and its cleanliness were confirmed by running the 27,274 ft. (8313 m) of 9 ⅝-in. liner in the 12 ¼-in. intermediate hole problem-free to TD.

Mud WeightPlastic ViscosityYield Point6-rpm10 sec Gel10 min GelHTHP FLElectrical StabilityLGS %
lb / gal / sg cP lb / 100 ft2 lb / 100 ft2 lb / 100 ft2 lb / 100 ft2 ml / 30 min Volts %
10.65 / 1.27 22 23 21 21 32 12.1 285 1.86
10.65 24 20 17 18 25 11.7 284 3.23
10.65 24 21 19 22 27 11.5 308 1.45
10.4 / 1.24 23 21 20 19 26 11 662 2.49
10.2 / 1.22 21 19 15 17 22 11.5 645 1.9
10.3 / 1.23 26 17 17 20 26 3 972 2.42
10.35 23 19 16 21 28 3.4 848 3.49
10.4 24 16 15 20 31 3.2 726 6.99
10.5 / 1.26 29 17 13 17 27 2.6 669 6.32
10.35 / 1.24 26 15 14 15 27 2.6 660 5.73
10.35 28 18 12 18 28 2.4 658 6.89
10.35 27 15 12 16 31 2.4 658 7.11
10.4 27 18 13 18 29 2.4 708 7.98
10.4 29 20 12 12 24 3 709 6.96

Table 1. The main mud properties while drilling the 12 ¼-in interval shown every 2500 ft (762m). The rheological properties presented were measured with Fann 35 Rheometer @120°F (49°C).


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