No abstract

No abstract

It is difficult to control and manage the start-up of a petroleum offshore platform. In order to solve this problem an intelligent system can play an important role, since available qualified operator and design knowledge can be easily implemented to assist the operator during start-up. This paper describes a system applied to the start-up of a petroleum offshore platform. The intelligent system has many heuristic rules to implement the automation of procedures, like the opening of many on-off valves while simultaneously monitoring process variables. This system can shorten the start-up time by 30%. This intelligent system is operating since June 1999 in the Petrobras P-19 platform, the Brazilian Oil Company, in Campos Basin, Brazil. This paper follows reference [1] that presented the operating interface of this intelligent system. Introduction The start-up of an offshore production unit is a complex operation, with risks for personnel, equipment and environment. On the other hand, as a production platform has many interlock loops, the frequency of emergency shutdowns, and consequently start-ups, is higher than those of conventional industrial units, like refineries or petrochemical plants. Thus, an automation system, which minimizes time for recovery of the platform production, can give noticeable improvements in economical performance, unit safety and procedure standardization. This paper presents the application of an expert system to the start-up automation of the Petrobras-19 (P-19) platform in Campos Basin, Brazil. As mentioned, this automatic system can result in smoother and more economic plant operation, fewer operating errors, fewer product rejects and also reduction in the possibility of damage to personnel, equipment, and environment during start-up. Plant Overview The platform, Petrobras-19, is a semi-submersible offshore production unit. It is operating in about 770 meters water depth and 105 km off the northern shore of Rio de Janeiro State. The oil processing systems consist of three major components: crude oil separation equipment, water injection facility, and gas-lift compression system. A schematic overview of the oil processing systems of the platform, P-19, is shown in Figure 1. After crude oil is separated into oil, gas and water, the oil flows to pipelines. Gas will be used in the power plant for fuel and gas-lift operation, with excess being exported. Water will be treated prior to discharge overboard. The gas lift facility includes a treatment plant, compressors, knockout drums, and gas coolers to recycle the gas in the process plant. The water injection facility components include filtration, deaeration, chemical injection and high-pressure water injection pumps.

During the operation of complex process, such as oil production or refining, abnormal situations may occur, leading to an alarm flooding. Alarm flooding is the signalling of a large number of alarms in a few minutes, in such a way that it is impossible for the operator to attend to all alarms. On these occasions, it is usual that the operator leaves the alarm summary list and gets an analysis of the plant through the screens of the DCS (digital control system), seeking to understand the situation. The alarm summary list ceases to be a useful tool. In such cases, the operator might have the aid of a filter that would present the highest priority alarms and other information associated with them, enabling him to gain a better knowledge of the situation. This paper describes the interface of a system aimed to help the operator to have a more comprehensive knowledge of the process (a better situational awareness) during process upsets that cause alarm flooding, recovering the utility of the alarm layer to the safety of industrial processes.