Temperature-resistant microcross-linked tackifier and high-temperature-resistant solid-free water-based drilling fluid

The invention relates to a temperature-resistant microcross-linked tackifier which integrates temperature-resistant and tackifying, salt-resistant and de-filtration properties and a high-temperature-resistant solid-free water-based drilling fluid. The high-temperature-resistant solid-free water-based drilling fluid comprises the following raw materials: fresh water, a temperature-resistant microcross-linked tackifier, a de-filtration agent, an inorganic salt and a deoxidant, wherein the temperature-resistant microcross-linked tackifier is a copolymer generated by reaction of alkenyl sulfonic acid, alkenyl amide and alkenyl benzene. The temperature-resistant microcross-linked tackifier at least has the following advantages: the temperature-resistant microcross-linked tackifier has prominent temperature-resistant and salt-resistant properties, and integrates the tackifying and de-filtration properties, and on this basis, the performance demand of the drilling fluid is combined, so that the high-temperature-resistant solid-free water-based drilling fluid has excellent temperature-resistant capacity. When the solid-free drilling fluid is prepared, only certain concentration of the temperature-resistant microcross-linked tackifier and less de-filtration agent and deoxidant are added without addition of other processing agents, so that the system composition is simple, the varieties of the processing agents are fewer, and the preparation and maintenance are convenient.