Copolymeric filtration-control sealing additive
Improves the performance of highly inhibitive water-based drilling fluids.
SILDRIL L shale inhibitor is a water-soluble sodium-silicate liquid with a 2.6 to 2.8 SiO2 to Na2O ratio. It can be used to provide superior chemical inhibition to reactive shales, clay and claystone formations, chalk formations, and formations interbedded with dispersive clays.
Treatment with 8% by volume is the most effective maintenance concentration for optimal inhibition.
SILDRIL L shale inhibitor is formulated with conventional drilling-fluid polymers to achieve the required rheological and fluid-loss properties. The inhibitor is engineered without commercial bentonite.
The SILDRIL L shale inhibitor has been successfully used in the field with densities varying from 9 to 14 ppg [1.1 to 1.7 sg]. The temperature limitation of the system can be extended to 275 degF [135 degC] with the addition of GLYDRIL polyglycol systems.
The SILDRIL shale inhibitor reacts readily with Ca2+ and Mg2+ ions. High concentrations of divalent ions will deplete the effective silicate concentration and diminish its inhibitive performance. The SILDRIL system is, therefore, not recommended for drilling formations containing high concentrations of calcium or magnesium ions. The addition of monovalent salts (KCl and NaCl) enhances the inhibitive performance of the SILDRIL L shale inhibitor. The use of potassium carbonate can also be used to enhance inhibitive performance.