The present work is dedicated to the study of the effect of emulsifier synthesis parameters on the stability, rheological properties and fluid loss of oil-based drilling muds. The duration and temperature mode of direct amidation of fatty acids by diethanolamine are shown to have a marked impact on the composition of the products obtained, and, hence, the properties of drilling muds stabilized by these products. The dependencies of electrical stability of drilling muds on the time of emulsifier synthesis proceed through maximum point, while similar dependencies of structural-mechanical properties proceed through minimum points. Herein, for each synthesis temperature, the value of maximal electrical stability corresponds to position of minimum points of yield point and gel strength. An increase of the temperature of synthesis promotes increasing of electrical stability of drilling mud and reduction of its structural-mechanical (shear stress) properties. The ranges of optimal process duration are determined for three temperatures, i.e. 150 °С – 2-5 h, 170 °C – 1-2 h, and 190 °С – 30-60 min. Plastic viscosity, thixotropic properties and fluid loss of drilling mud are shown to be independent on the emulsifier synthesis conditions. It is also concluded that the degree of conversion of fatty acids and the amount of water formed during the synthesis cannot be considered the criteria for completion of the process.
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