Research progress of clay transformation in drilling fluids

As an important slurry material for water-based drilling fluids, montmorillonite has been widely used in oil because of its excellent properties such as expansibility, dispersion and suspension, making, cation exchange adsorption. However, at a certain temperature pressure, will transform into illite, chlorite other minerals, changing the fluids. In order to systematically summarize sort out current research status transformation, this study focused on progress transformation minerals under different pressure conditions, summarized mechanism montmorillonite. The is transformed illite by adding K + interlayer spacing removing Si 4+ Al 3+ tetrahedron structure. conversion Fe 2+ , Mg2 ions octahedron, replaced . precipitated brucite layer connected with upper lower layers.