Abstract: Digital twin has shown great potential in real-time data analysis, engineering design optimization, and equipment health diagnosis and has become a key technology for achieving the digital transformation development of the oil and gas industry and accelerating the next generation of technological innovation in the oil and gas industry. However, due to the imperfect software and hardware in drilling & completion engineering and the unclear research methods, the technology is still in the initial stage. On the basis of discussing the concept and technical characteristics of digital twin in the drilling & completion engineering of oil and gas fields, the latest application progress of digital twin in pre-drilling design, monitoring during drilling, and completion, and operation training of the drilling & completion engineering was introduced, and the application scheme of digital twin in drilling & completion engineering was proposed. The key technologies and methods of digital twin were discussed, and the problems existing in the application of digital twin in drilling & completion engineering and related industries were analyzed. In addition, some suggestions for the development of digital twin in the oil and gas industry were put forward. The results can provide a theoretical basis and method guidance for the application of digital twin in the oil and gas industry, so as to accelerate the digitization process of the oil and gas industry, improve the development efficiency of oil and gas fields, and promote the comprehensive construction of smart oil fields.