SILDRIL D additive is a water‐soluble sodium silicate powder used for primary chemical wellbore stabilization. Secondary inhibition is achieved with the use of KCl or NaCl.
SILDRIL D additive is a water‐soluble sodium silicate with a 2.0 ‐ 2.8 SiO2 to Na2O ratio. SILDRIL D additive can be used to provide superior chemical inhibition to shales, clay and claystone formations, chalk formations, and formations interbedded with dispersive clays. Treatment with 43 to 86 kg/m3 (15 to 30 lb/bbl) is the most effective maintenance concentration for optimum inhibition. Treatment with monovalent salts (KCl and NaCl) enhances the inhibitive performance of SILDRIL D additive. The use of potassium carbonate can also enhance inhibitive performance. SILDRIL systems are formulated with conventional drilling fluid polymers to achieve the required rheological and fluid loss properties.
The SILDRIL system is engineered without commercial bentonite, although small quantities (3 ‐ 5 lb/bbl) can be used in initial fluid make‐up. The SILDRIL system has been successfully used in the field with densities varying from 1.1 to 1.7 sg (9 to 14 lb/gal). The SILDRIL system has the same temperature limitation as all other polymer‐base fluids, approximately 300°F (150°C).