Research on the Evaluation of 10,000-Meter Ultra-Deep Well Lost Circulation Material Properties Resistant to 240 °C High Temperatures

During the drilling process of 10,000 m deep wells, loss zones face complex environments with ultra-high temperatures and pressures. Traditional bridging plugging materials exhibit insufficient temperature resistance and tend to carbonize under downhole high-temperature conditions, leading to recurrent loss. To address the technical challenges of drilling fluid loss in ultra-high-temperature formations of 10,000 m deep wells, experimental research was conducted to evaluate the properties of plugging materials resistant to 240 °C. Rigid particles, elastic particles, flaky materials, and fiber materials resistant to 240 °C were optimized. An experimental evaluation method for ultra-high-temperature dense pressure-bearing loss prevention and plugging formulations was established. The ultra-high-temperature while-drilling leak prevention formulation was optimized through sand disk plugging experiments. Millimeter-scale fracture plugging simulation experiments optimized ultra-high-temperature stop-drilling plugging formulations for different fracture apertures, achieving a bearing capacity of 15 MPa within 1–5 mm fracture apertures. Through the synergistic effects of various loss prevention materials, a reinforced force chain network structure forming a dense pressure-bearing plugging layer was achieved under 240 °C high-temperature conditions. This research provides material and system support for the solving drilling fluid loss challenges in high-temperature formations of 10,000 m ultra-deep wells.