On-shore supervision of off-shore gas production Human Factors challenges

Technology enables remote process control of off-shore gas production assets, thus reducing off-shore manpower. The human factors in control centre engineering include operator consoles, information presentation, interaction, alarm management, and job content. The human factors are all related to each other. Moving off-shore tasks to on-shore control centres requires a human factors approach, which includes an operator task analysis. For natural gas production, some new control room tasks appear, such as contract management and related production volume control. Two cases of Human Factors engineering of a move to shore are presented. At the first case, a hierarchical task analysis was performed to get insight in the operator tasks. This enabled determination of the number and size of workplaces and revealed the importance of contextual off-shore platform information. Several years later, increased data transmission capacity between onand off-shore, led to the implementation of an advanced alarm management philosophy, including an optimal visualisation of (grouped) alarms. The second case also concerned the design of an on-shore control centre for over 40 off-shore gas production assets. A major effort concerned the redesign and standardization of process graphics, in order to enable on-shore operators to supervise all processes adequately. Human Factors in Control Centres The aim of Human Factors (HF)/Ergonomics is to optimize the work system. Ergonomics can be defined as user-centred design, or user-centred engineering. The value of ergonomics is beyond health and safety (Pikaar, 2007). This definition expresses a focus, both on the human being and design. In general terms, this requires an approach including both social and technical aspects of the system. Job design, operator workload, control centre layout, workplace layout, instrumentation, information display, environment, and many more topics have to be addressed. The HF professional may not have much background in process control or other engineering sciences. Therefore, he relies on a systematic analysis and design approach (ISO 11064, 1998). He tries to get insight in the relationships between relevant human factors, such as operator workload and job design, or the number of screens on a console and the measurements of the workplace. In addition, HF may fill the gap between technical engineering disciplines and users. Of course, a close cooperation between HF professional and technical engineering disciplines will be needed. The aim of this paper is to show the impact of a structured HF involvement in control centre design projects. This paper is based on case studies. For methodological reasons, case studies may not be considered of scientific value. A project is never carried out twice (with or without ergonomics) to find out whether ergonomics makes a difference. Nevertheless, the authors believe that HF experiences in industrial settings should be reported in literature notwithstanding the methodological problem of N=1. Publication is considered essential to bridge the gap between science and practice (Pikaar, 2012). It should be noted that the system ergonomics approach to engineering projects is also the same (refer to the next section). The following related major topics need to be addressed in the overall control centre design project: 1) job content and operator workload, 2) workplace design – operator console, 3) process graphics, 4) interaction design – navigation and control, and 5) alarm management (EEMUA, 2002; Pikaar et.al., 1998). Each topic may be a (large) project on its own. Moving an off-shore control room to shore is not different from other control centre design projects from a HF point of view, which will be illustrated by case material. Ergonomics Engineering steps Usually, an engineering project passes through several phases, starting with a feasibility study, via several design steps, to detailed engineering and implementation, as shown in figure 1 (Pikaar, 2007). Highlights of the HF engineering steps are discussed below. The HF professional needs knowledge of the actual operator tasks. Based on this knowledge, an accurate estimate of the new control room situation can be made (functional analysis). The main issue will be to what extent operator tasks change, when moving an offshore control room to shore. Step 1. Feasibility Step 1 typically includes a review of the project owners’ HF assumptions regarding work load, level of automation, and capabilities of operators. For the HF professional, it is important to be aware of such assumptions, and if needed, give feedback on a general level. For example, one could temper a too optimistic view on the number of operators needed. Step 2. Problem definition This step starts with a general description of the project and the purpose of the system to be designed. The outline of the design steps have to be negotiated with project management, including design constraints. Step 3. Situation analysis The aim of the situation analysis is to gain insight in existing and future tasks. It includes collecting formal documents and drawings of the existing system, analyzing work tasks by observations and interviews, and gathering knowledge on the new system (to be designed). Step 4. Functional Design Specification The functional design specification concerns the allocation of system tasks. An allocation procedure includes a discussion on the level of automation, job requirements, and the design of a local work organization. Topics are 1) the allocation of tasks to workplaces, 2) the lay out of a system, 3) shape and size of workstations and instruments, and 4) environmental requirements. Step 5. Detailed Design/Engineering On the basis of functional design requirements, various design solutions can be developed. Choices have to be made, which implies weighing all aspects involved, including ergonomics. Tools to illustrate the results may be 3D-drawings, mock-up evaluations, or prototyping of graphics. Figure 1. General project procedure and related ergonomic engineering steps. Step 6. Implementation (building the system) Typically, the construction phase starts with the production of workshop drawings and building site drawings. A HF contribution is needed to avoid some typical errors. For example, an operator console may have been specified with two supporting legs. The workshop engineer decides that a third leg is needed for stability. He locates the additional leg in the middle of the console, which happens to be the central work position of the operator, thus reducing his leg room. Step 7. Commissioning & step 8. Evaluation Once finished, the formal commissioning of a working system is organized. Typically, the HF professional should review workplaces, information display and GUI’s. Ideally, after a year, an evaluation of the running system should be organized, for example resulting in feedback on design and engineering of the project. Case studies – general context Over the years, the authors have been involved in several cases of moving operator tasks from North Sea natural gas production facilities to land based control centres. Several companies are active in this area, each operating several dozens of platforms. Satellite platforms produce onto larger platforms, which have recovery units for glycol and ethanol. Larger platforms are manned and have a local control room. Piping connects the platforms to a main entry point for shore going sales gas. At main platforms, usually a 24/7 manned control room can be found. In the 90’s, the authors redesigned their first on-shore control room. The control room was equipped with cctv-camera’s, surveying the displays panels in several off-shore control rooms. Thus, off-shore operators could go to sleep, while colleagues watched their safety. In case of an alarm, a wake up call was placed. Recently, the authors have been involved in two projects of moving a control room to shore. The main projects of case 1 case concern: 1) control centre and workplace layout, 2) central process overview graphic, and 3) alarm management. The main projects of case 2 are: 1) control centre and workplace layout and 2) process graphics redesign. The company of the second project was aware of the earlier findings at the first company. They visited this companies’ operational control centre and copied several findings. The following sections give some highlights of both projects, however they are no full account of HF contributions. Case 1A – Control room design Starting point was a small on-shore control room for land based gas production assets and the off-shore gas receiving station. After selling the on-shore assets, the control room was moved to another location, tasks to be extended to supervise approximately 25 off-shore assets. Process supervision was based on <10% of the off-shore process control variables. The HF contribution to this project can be summarized by some key factors (more details can be found in Pikaar, 2007): – project scope upgrading and moving of an existing control room to another location – investment € 200.000 exclusive of instrumentation and communication systems – % HF engineering 10% of total investment / 200 hours – management project owners’ engineering department – project team HF engineer, architect, and instrument engineering contractor – main topics room layout, workplaces, detailed design, large screen overview graphic – workplaces one double operator console, office desk, social area – role HF professional project management, ergonomic design. The project was organized along the system ergonomics engineering steps, as described earlier.