In this paper we highlight experiences from two cases of drilling automation, emphasizing the importance of understanding work and human factors in the design and implementation of automated systems. Automation is advancing as a means to increase efficiency, quality and safety in various industries, including petroleum. However, there has been limited sociotechnical studies of automation in the petroleum industry. Experiences from other domains indicate that gradual automation in collaboration with users has improved efficiency, safety and user satisfaction. Using thematic analysis of interviews with technology providers, consultants, drilling operators, and project leaders, we found that from the outset of the projects, a balance between technology optimism and understanding of human limitations and experiences was critical. Furthermore, we identified several challenges and potential remedies in areas such as user involvement, system integration and alarm handling, use of appropriate methods and standards, sensemaking of automated systems, and competence and training of operators. The case studies illustrate a need for improved management of human factors in the development and implementation of automated technology in the petroleum industry. The concepts of work-as-imagined (WAI) and work-as-done (WAD), and the potential gap between these, are useful to highlight the importance of applying the appropriate human factors expertise and methods for such development.