An expert system is a computer software technique which is best (but not necessarily) implemented using languages and hardware systems from the artificial intelligence stable. The software technique offers the potential to encapsulate the experience and knowledge from many human experts and to effectively communicate it to other experts. The knowledge is mostly expressed in simple rules from which the expert system makes inferences that lead (to other rules and ultimately) to solutions to problems. The feasibility of building real time expert systems for applications in control rooms of process plants has been proven. Companies with sharp forward plans are investing in such systems now in order to obtain early benefits. The benefits can manifest themselves in improved security of production which is frequently directly quantifiable as cost savings. In 1984 the author led the team which provided one of the first practical demonstrations in the UK of a real time expert system for process control room applications. Here he reflects on practical issues of the pioneering exercise and some of the experience obtained whilst evaluating feasibility of large scale applications with European oil and gas companies. (Fig 1)
