Saturated salt water drilling fluid of salt response type intelligent polymer and preparation method thereof

A saturated salt water drilling fluid of salt response type intelligent polymer, wherein the drilling fluid consists of bentonite, NaOH, KCl, calcium carbonate, barite, NaCl, supramolecular fluid loss additive, supramolecular shear-enhancing agent, plugging agent, coating agent and water;

• the supramolecular shear-enhancing agent is zwitterionic polyacrylamide;
• the supramolecular fluid loss additive contains structural unit A, structural unit B and structural unit C;
• the structural unit A is a structural unit with the structure shown in formula (1);
• the structural unit B is a structural unit with the structure shown in formula (2);
• the structural unit C is a structural unit with the structure shown in formula (3);
• the weight average molecular weight of the supramolecular fluid loss additive is 50000 to 500000;
• wherein the bentonite is contained in an amount of 1-6 parts by weight relative to 100 parts by weight of water;
• the content of the NaOH is 0-3 parts by weight;
• the content of the KCl is 0-8 parts by weight;
• the content of the calcium carbonate is 0-8 parts by weight;
• the content of the barite is 0-180 parts by weight;
• the content of the supramolecular fluid loss additive is 0.1-4 parts by weight;
• the content of the supramolecular shear-enhancing agent is 0.1-4 parts by weight;
• the content of the plugging agent is 2-6 parts by weight;
• the content of the NaCl is 0-36 parts by weight;
• the content of the coating agent is 0-0.8 wt %.