Optimization of rheological characteristics of xanthan-based solutions for washing liquid treatment

Abstract

Relevance. Within the limits of the isolated concentrations of xanthan and salts, optimization of rheological parameters of a pseudoplastic liquid intended for thickening drilling mud is shown. For this purpose, it is proposed to isolate from the complete rheological curve the separation of the liquid liquefaction section, according to which the nonlinearity parameters are determined. The complete factorial experiment allows us to specify the dependence of rheological nonlinearity on the concentration of ingredients. The formulation of the complete factorial experiment makes it possible to qualitatively evaluate other brands of biopolymers. Based on the non-linearity indicators, an indicator for optimizing the carrying capacity of drilling fluids is proposed. The use of the above and characteristic viscosity of the solutions can serve as qualitative and quantitative estimates of the projected compositions of drilling fluids. The multiplicity of brands of xanthan gums determines their qualitative diversity. The choice of gum for thickening drilling fluids is not formalized. The article offers one of the options. Aim. Using the Ostwald de Weil model to evaluate the rheological characteristics of aqueous solutions of DUO-VIS xanthan gum in the presence of Na and K chlorides at elevated concentrations of xanthan and salts, as well as to analyze the effect of the dispersed phase of the thickener solution on its rheological characteristics. Methods. Instrumental methods for determining the parameters of drilling fluids according to SS 33213-2014, mathematical modeling using a complete factorial experiment. Results and conclusions. Using the example of a DOU-VIS xanthan solution applied as a thickener for drilling fluids, the S-shape of the viscosity profiles of solutions of xanthan thickeners is shown. The paper considers the example of highlighting a section of the viscosity curve with decreasing viscosity and approximating it by a power dependence. The effect of biopolymer and potassium chloride (within the limits of their isolated concentrations) on the parameters of the power dependence used as an approximated viscosity curve is shown using a complete factorial experiment. The paper introduces the distribution of the optimization parameter, which is the ratio of the consistency coefficient to the nonlinearity indicator, within the range of changes in the concentrations of biopolymer and KCl. An example of calculating the volume fraction of biopolymer macromolecules in solution is shown and the application of the reduced and characteristic viscosities for estimating solutions at the scale of suspension particles is given.

Keywords

• biopolymer drilling fluids
• xanthan gum
• consistency coefficient
• viscosity properties
• power rheological law