Schlumberger

Case Study: SAFE-SURF Y Surfactant Meets Norwegian Pollution Standards in Field Trial

Challenge: Due to environmental restrictions cited in the Norwegian Pollution Authority (SFT), an operator needed to replace the wellbore clean-up chemical to be used following application of an oil-based drilling fluid.

Solution: M-I SWACO suggested the application of a newly developed “yellow” surfactant, SAFE-SURF Y. The SAFE-SURF Y surfactant is a blend of non-ionic surfactants and powerful wetting agents designed to clean up and displace oil- and synthetic-based drilling fluids and solids. EMI-1739 surfactant will emulsify oil- and synthetic drilling fluid components into the water phase and prevent re-deposition of oil-wet solids onto pipe surfaces. It disperses filter cakes efficiently with low environmental impact, while leaving downhole tubular and casing in a water-wet condition. This contributes to reduced filtration costs, reduced formation damage, increased well productivity, and lower overall well costs.

Result: Incorporating the SAFE-SURF Y surfactant in a surfactant/solvent wash train proved to be highly successful. The well cleaned up at a much earlier stage compared to offset wells, attaining the required nephelometric turbidity unit (NTU) readings with minimal circulation of seawater. The results of this field trial were:

  • Cleaner packer fluid returned at surface
  • Significant reduction in volume of slop generated
  • Reduced circulation time/rig time of the completion phase

Well Information
Location Ekofisk Field, Offshore North Sea, Norway
Interval 8½-in. section, cleanup of 6½-in. liner, 9⅝ and 10¾-in. casing
Disposal method Injection

The Situation

Due to environmental restrictions cited in the Norwegian Pollution Authority (SFT), an operator needed to replace the wellbore clean-up chemical to be used following application of an oil-based drilling fluid. To meet the environmental requirements in this location, the operator needed a “yellow category” product.

The Solution

M-I SWACO suggested the application of a newly developed “yellow” surfactant, SAFE-SURF Y. The SAFE-SURF Y surfactant is a blend of non-ionic surfactants and powerful wetting agents designed to clean up and displace oil- and synthetic-based drilling fluids and solids. EMI-1739 surfactant will emulsify oil- and synthetic drilling fluid components into the water phase and prevent re-deposition of oil-wet solids onto pipe surfaces. It disperses filter cakes efficiently with low environmental impact, while leaving downhole tubular and casing in a water-wet condition. This contributes to reduced filtration costs, reduced formation damage, increased well productivity, and lower overall well costs.

The Results

Incorporating the SAFE-SURF Y surfactant in a surfactant/solvent wash train proved to be highly successful. The well cleaned up at a much earlier stage compared to offset wells, attaining the required nephelometric turbidity unit (NTU) readings with minimal circulation of seawater. The results of this field trial were:

  • Cleaner packer fluid returned at surface
  • Significant reduction in volume of slop generated
  • Reduced circulation time/rig time of the completion phase

The Details

A 12.3-lbm/gal (1.48-SG) VERSATEC oil-based drilling fluid was displaced out of the well by pumping the following sequence of pills:

  • Base-oil
  • High-viscosity surfactant pill with SAFE-SURF Y
  • Low-viscosity solvent pill
  • High-viscosity surfactant pill with SAFE-SURF Y

This sequence was followed by seawater. As shown in the graphs, clean fluid returned at a much earlier stage compared to previous/similar wells.

Summary

In addition to the HSE benefit, the following benefits were observed during this operation:

  • 30% reduced time consumption.
  • 25 to 30% reduction in volume needed to reach the target NTU.
  • The logistical impact of this operation reduced volume of slop by 28% (from an average 2,900 to 2,100 bbl of slop).

Download: SAFE-SURF Y Surfactant Meets Norwegian Pollution Standards (0.81 MB PDF)

Contact Us

Learn More

Nephelometric Turbidity Unit Nephelometric Turbidity Unit Nephelometric Turbidity Unit
PrevNextZoom1 of 3