Analysis of waste mud stability

Abstract

Drilling fluids play a number of functions, e.g. they remove cuttings, lubricate the drill bits, maintain stability of the hole and prevent the inflow-outflow of fluids between well and the shales. For this reason, they are made of complex polymeric-mineral microcomposites of differentiated chemical and mineralogical-phase content with varying share of colloidal phase in dispersed solid phase in water, i.e. water-based muds (WBM) or oil environment, i.e oil-based muds (OBM). The major factor providing stability of the presented systems is the high participation of clayey minerals (smectite group), long-chain polymers and chemicals stabilizing dispersions. The results of analyses of concentrated dispersions of waste muds from a few regions in Poland are presented int he paper. These are plastic-viscous dispersions of rheological parameters described most frequently by the Herschel-Bulkley model, the flow of which is connected with deformations of internal structures in the analyzed systems taking place in a function of temperature. There are also presented measurement results of light transmission and backscattering in the analyzed range of temperatures, i.e. 20 to 60°C with the use of Turbiscan Lab., Formulaction. The stability indicator is the turbiscan stability index (TSI).