Since the Industrial Internet of Things (IIoT) became its own domain, in parallel with consumer-oriented IoT, various industries have been successfully deploying such systems – initially as pilot projects, and more recently at scale. Meanwhile, the O&G industry, hurt by the price of oil, postponed investments in new technologies. Nevertheless, there are now multiple successful case studies of IIoT in O&G. This paper contains a high-level review of several such IIoT projects in O&G and aims to help the reader gauge the results achieved in this area. By examining these cases and looking at the similarities and differences with applications in other industrial sectors (transportation, water management, utilities…), the O&G industry can derive guidance in its adoption of IIoT, in particular by identifying the "lowest-hanging fruit" to improve operations and reduce human and equipment costs. While there is still confusion in terms of standards, choice of technologies, and myriad actors of all sizes, this is neither new in our industry nor unexpected in an emerging field; these challenges should therefore not prevent others from moving forward.