Abstract: Based on a brief introduction to the origin of digital twin technology and the research status of its applications in drilling engineering in the petroleum industry, some key technologies were advanced, including the development of digital twin of the wellbore, digital twin of the geological environment, digital twins of drilling rigs, the simulation of downhole dynamic processes, and the real-time interaction technology of physical-digital twins, etc. Then, six application scenarios were designed for the digital twin technology: namely pre-drilling prediction and optimization by simulation, rehearsal of teamwork for complex well drilling, early warning and decision-making while drilling, remote drilling control, predictive maintenance of drilling equipment, and drilling training. Further, the major research and development focuses were proposed regarding the digital twin system for drilling. Finally, the research and development difficulties of digital twin technology applied in drilling were analyzed together with corresponding countermeasures. The research results provide a technical reference for speeding up the practical applications of digital twin technology in drilling engineering and promoting the digital and intelligent transformation of drilling engineering.