<p>A study was carried out on the feasibility of obtaining a composite hydrogel reagent derived from a polyelectrolyte complex of anion-modified sodium lignosulfonate and cationic starch. The reagent was tested using impedance measurements to determine the dependence of the impedance of an electrochemical cell on the alternating current frequency. The introduction of phosphonic groups to modify the lignosulfonate composition suggests the possibility of additional complexes for greater reduction of the viscosity and enhanced heat stability of the drilling mud product. Cationic starch forms the basic structure of this gel, while the modified lignosulfonate improves the mechanical and rheological properties of the mud. This interaction leads to the formation of a mesh structure that increases the viscosity and resistance to decomposition. The hydrogel drilling fluids derived from this composite reagent facilitate more efficient removal of the drill cuttings and greater inhibition of hydration, swelling and disintegration of clays and shales during drilling.</p>