Investigation of filtration properties of a formate-based mud system under high temperature conditions

Using the methods of design of experiments, filtration properties of the bentonite-free mud system that contains xanthan gum, starch, sodium and potassium formate salts, calcium carbonate and Alevron agent at temperature range of 130–170 °C, differential pressure of 1–5 MPa and initial permeability of ceramic filters of 0.95–7.20 D were studied. Regression models were built for the НТНР filtration loss and permeability of a ceramic filter after mud cake build-up depending on mud additives concentrations, temperature, differential pressure and initial filter permeability, which provide high accuracy of experimental data approximation.