Technical Bulletin

Description :

Glyco Dril MC polyglycol is a medium-cloud-point additive designed for medium-to-high salinity polyglycol systems. It can provide improved wellbore stability, lubricity, high-temperature filtration control, plus reduce dilution rates and bit balling. While polyglycols are most effective when used in conjunction with an inhibitive salt, such as KCl, in a non-dispersed polymer system, they can be used as additives in most water-base systems. Glyco Dril MC  polyglycol is acceptable for most applications specifying low-toxicity additives.

Application and Use :

Glyco Drill MC product has application in polyglycol systems in fresh-to-medium high salinity make-up water and can be used in wells withmoderate formation temperatures. When used properly, this medium-cloud-point additive helps to stabilize troublesome shales by plugging
shale pores, preventing the equalization of hydrostatic pressure away from the wellbore.
Polyglycol systems are generally low-to-medium density, non-dispersed polymer systems utilizing an electrolyte to activate the cloud pointpolyglycol. They have application where troublesome water-sensitive shales are to be drilled, and can be used in lieu of oil-base systems for certain applications.

Glyco Drill MC  polyglycol can be used in thermally activated mud emulsion (TAME) applications (near the cloud point) or in situations where it is insoluble (above the cloud point).Normal concentrations of Glyco Drill MC  polyglycol range from 2 to 5% by volume of the liquid phase or 7 to 17.5 lb/bbl (20 to 50 kg/m3). After the initial treatment, periodic treatments should be made to maintain the desired concentration. A field test method is available from the Rx Marine International Technical Service Department to monitor the concentration of Glyco Drill MC polyglycol. Above the cloud point,

Glyco Drill MC  polyglycol is insoluble and tends to increase the plastic viscosity (as all insoluble additives do).“Cloud point” is the temperature where polyglycol additives change from being soluble (at lower temperatures) to being insoluble (at higher temperatures). Shale inhibition is improved when the polyglycol is insoluble or “clouded out.” The cloud point temperature can be reduced by increasing salinity (or other electrolytes) and/or by increasing the concentration of Glyco Drill MC .

Dose :

Glyco Drill MC is applied at concentrations ranging from 2% to 5% by volume. The actual value used depends on salt type and concentration as well as the downhole temperature range. As a general rule, the salinity of the drilling fluid is engineered such that one-third of the additive concentration of Glyco Drill MC is clouded out at bottomhole circulating temperature.

Physical Properties:

Appearance : Brown, slightly viscous liquid
Density         :1.00 to 1.05 SG
Pour point    :<10°F <–12°C
Flash point  :>284°F >140°C
Solubility      :Soluble at 68°F (20°C

Advantages:

• Improved wellbore stability and shale inhibition.
• Improved lubricity.
• Improved high-temperature filtration control.
• Reduced dilution rates and mud consumption.
• Reduced bit balling potential.
• Low toxicity.

Enhances thermal stability of polymers

• Is unaffected by contaminants
• Is compatible with most salts and water-based fluids
• Can be used in combination with other glycols

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