Laponite-polymer composite as a rheology modifier and filtration loss reducer for water-based drilling fluids at high temperature

In the process of deep oil and gas drilling, high temperature and high amounts of salt will greatly deteriorate the rheological properties of water-based drilling fluids (WBDFs), increase the fluid loss of drilling fluids, and seriously threaten the safety of operations. It is urgent to develop new high-temperature and salt-resistant drilling fluid additives. In this study, a novel organic-inorganic polymer nanocomposite (P-RD') was synthesized by combining laponite and polymer, and its chemical structure and properties were characterized and evaluated by various experimental methods. The results show that P-RD' forms a spatial network structure in aqueous solution, and has good clay adsorption capacity and pore and crack sealing ability. At 180 °C and 15 wt% NaCl, it has good rheological stability to WBDFs, the American Petroleum Institute (API) filtration loss is only 7.1 mL, and the high temperature and high pressure (HTHP) filtration loss is controlled at 29.2 mL. P-RD' has dual functions, which can effectively strengthen the temperature and salt resistance of WBDFs, and is expected to be used as a rheology modifier and filtration loss reducer in high-temperature deep well drilling.