Effectiveness of Chloride Salts in Shale Swelling Inhibition: An Assessment of Its Impact on Drilling Fluid Performance

The present research work presents a comprehensive study of the impact of inorganic salts on shale inhibition. Variable concentrations (1%, 3%, 7%, and 10%) of NaCl, KCl, MgCl₂, and CaCl₂ were utilized to systematically analyze their shale inhibition features. Different parameters such as conductivity, linear swelling, capillary suction timer, zeta potential, particle size analysis, and dispersion stability of the water-based drilling mud were analyzed to estimate the effectiveness of the different concentrations of the salt additives. The outcomes revealed that the NaCl and KCl solutions demonstrated better swelling control, i.e., 66.2% and 62.1%, respectively, as compared to CaCl₂ and MgCl₂, i.e., 87.3% and 93.6%. The assessment of CST data shows that the capillary suction time was effectively controlled by the KCl salt solution. The value of zeta potential becomes less negative with the increase in concentration of salts. The agglomeration of clay particles was observed after the addition of 1%, 3%, 7%, and 10% of NaCl, KCl, MgCl₂, and CaCl₂. The observation of dispersion stability of the Na-Ben in the presence of different concentrations of salts demonstrated highly stable dispersion in the presence of NaCl. The microstructural analysis of Na-Ben treated with different inorganic salts was done by capturing the SEM images. The outcomes of this comprehensive study have significant implications for the oil and gas industry, as they enhance our understanding of the role of inorganic salts in improving the shale inhibition properties of water-based drilling muds.