Summary High-temperature and high-pressure (HTHP) conditions pose enormous challenges to drilling operations, as resource and energy exploitation continues to move into deeper strata. However, current drilling technology is unable to satisfy the demands of the extreme HTHP environment, prompting the development of high-performance drilling tools and supporting technologies that are capable of adapting to extreme situations. For the development of drilling tools, in-situ testing based on actual drilling projects is risky, costly, and inefficient, while HTHP drilling tools testing equipment can avoid these problems. This paper summarizes previous research on HTHP drilling tools testing equipment and its optimized design and provides an overview and discussion of the equipment’s component structure and operating mechanisms. HTHP drilling tools testing equipment typically consists of several major subsystems, including the heating system, pressurization system, wellbore, data acquisition and control system, sealing system, and drive mechanism. Through a systematic comparison of key parameters and functional characteristics, the core technical bottlenecks in HTHP drilling tools testing can be identified. These challenges primarily involve: (i) accurate simulation of the thermo-hydromechanical-chemical (THMC) coupled field; (ii) material degradation and structural damage induced by long-term cyclic testing; (iii) the authenticity, reliability, and real-time capability of multiparameter measurements; and (iv) the insufficient performance and long-term reliability of supporting equipment. In addition, issues pertaining to the long-term reliability and safety of HTHP drilling tools testing systems, as well as considerations of cost-effectiveness and economic viability, are also examined. Accordingly, prospective research directions are proposed, including the development of fluid circulation architectures suitable for extreme HTHP conditions, the design of robust dynamic sealing technologies with sustained HTHP resistance, the advancement of noncontact and near-bit sensing techniques for high-precision real-time acquisition of thermo-hydromechanical parameters, and the creation of long-life sensors and pumps reliably operating at up to 300°C and 150 MPa. It is anticipated that these insights will serve as a valuable reference for researchers and engineers in related fields.
Yin et al. (Fri,) studied this question.