Thermal Insulation Performance Evaluation and Installation Length Optimization of Inner Coating Thermal Insulation Drillpipe

With the exploration and development of oil and gas resources moving towards deeper areas, there is an increasing number of high-temperature wells being drilled. However, during drilling, the temperature of the drilling fluid at the bottom of the well may exceed the temperature limits of the rotary steerable system, logging while drilling, and other downhole tools. This poses a significant risk to the safety of the drilling operation. Therefore, it is urgent to study temperature control technology for drilling fluids in high-temperature wells. Inner-coating thermal insulation drill pipe is a new technology with significant application prospects. In order to study the thermal insulation performance of inner-coating thermal insulation drill pipe and consider the influence of the insulation coating, an equation for the wellbore temperature field during drilling with inner-coating thermal insulation drill pipe was established. Through case analysis, the thermal insulation performance of inner-coating thermal insulation drill pipe was evaluated, and the sensitivity of parameters was analyzed. An optimization method was developed for determining the installation length of inner-coating thermal insulation drill pipe. The installation length was optimized for various temperature-resistant conditions through case calculations. The research results show that inner-coating thermal insulation drill pipe has a positive impact on controlling the temperature of drilling fluid at the bottom of the well and has promising potential for widespread application. Only by installing 3500 m of inner-coating thermal insulation drill pipe can we meet the requirement for tools that can withstand temperatures of 150°C. This study can provide valuable insights for the design and application of inner-coating thermal insulation drill pipes in high-temperature wells. It is of significant importance for ensuring safe drilling operations in such conditions.