Water-based drilling and well-servicing fluids with swellable, synthetic layer silicates

摘要

Synthetic swellable layer silicates corresponding to the following formula MgO.aMA.bAl2O3.cSiO2.nH2O (I) in which M is Na+ and Li+ having an Na:Li ratio of at least 1; A is F-, OH- or 1/2O2- or a mixture thereof; a is 0.1 to 0.6; b is 0 to 0.3; c is 1.2 to 1.7; and n is 0 to 3.0. are used in water-based well-servicing fluids as a high-temperature-stable thixotrope substantially unaffected by alkaline earth metal ions.