Nano silica treated water based drilling fluid formulation and analysis in various polymers and salts systems

Abstract

This thesis presents the formulation of nano silica particle based water drilling fluid, its characterization and performance simulation study. A total of ten test matrix fluid systems were designed to investigate the impact of single and combined additives such as salts, polymers and Nano silica on the drilling fluid properties. The fluids have been characterized through their rheology, pH, and filtrate loss. Further the viscoelasticity of the selected nano based fluid systems were analysed. The performances of the fluids are also simulated through hole-cleaning and hydraulics behaviours. Several observations have been discussed in the main report. Among others, one formulation which allows 2.81ppb (8.0 kg/m3) KCl is a DUO-VIS and CMC polymer system. Fluid 1 is a nano based drilling fluid. When fluid 1 is treated with an ex-situ 0.3g Na2CO3 salt, the rheology improved greatly. The composition of the best Nano-silica based is:  Fluid 1: = 500g H2O + 0.1g Nano silica + 4g KCl + 0.75g Na2CO3 + 0.95g DUOVIS + 0.35g CMC + 25g Bentonite  Fluid 2 = Fluid 1 + 0.3g Na2CO3 (ex-situ) Finally, this thesis comes to the conclusion that the application of nano silica has shown positive and negative results. The negative results can be improved by treating with polymers, which creates a positive synergy. A positive effect nano is the result of using the right concentration in a given salt and polymer system. In addition, the performance of KCl in nano treated system could be improved with other salts such as NaCl and Na2CO3.