Influence of ionic hydration inhibitors on triple inhibition system mud properties - technological parameters

Abstract

Clay rock hydration is primary reason of borehole wall instability during drilling. In correspondence to this fact, it is substantial to counteract abovementioned phenomenon. It can be achieved e.g. applying ionic hydration inhibitors in the drilling mud formula. From the point of view of drilling effectiveness, the most practical is water based inhibitive mud. Its stabilizing properties are partially effect of soluble salts and low concentrations of polymer. This type of the mud exhibits good rheological properties and causes, in most of cases, increased rate of penetration (ROP). Ionic inhibition contribute to reduction of both dispersion and hydration of clay rock due to decreased instability of shales containing swelling clays. Hydration degree depends on the type and concentration of inhibitive ions in the drilling mud. This paper describes studies on influence of the chosen inhibitors ($KCl$, $K_{2}CO_{3}$, $HCOOK$, $CaCl_{2}$) on technological parameters of the developed drilling muds with triple inhibition system. Obtained results indicate good parameters of the mud. For $HCOOK$ and $CaCl_{2}$ increase of the inhibitor concentration causes major changes in mud parameters, however for $K_{2}CO_{3}$ and $KCl$ those parameters do not change significantly.