Mario Cesar Mello Massa de Campos

Dual composition control of a debutanizer column

Abstract Dual composition control, using decouplers, is a success on a debutanizer distillation column. For this particular unit, decoupling control has proven to be a simple and efficient technique that allows a significant operability improvement. Economic benefits realized by using this simple tool are significant.

Fast Offshore Wells Model (FOWM): A practical dynamic model for multiphase oil production systems in deepwater and ultra-deepwater scenarios

Abstract This work describes a simplified dynamic model for control and real time applications in offshore deepwater and ultra-deepwater petroleum production systems. Literature about simplified dynamical models, capable of cover the global architecture of an offshore multiphase production system, is scarce. Hence, the proposed model integrates and adapts partial models available in the literature in order to generate a single model of the whole system. The model, designed to represent slugs generated by the casing heading and terrain/riser concomitantly, was evaluated by comparison with a traditional commercial simulator and was also implemented in two actual production systems. As a result, the model showed the capability of capturing complex dynamical behaviors, such as limit cycles, demonstrated to be numerically more stable than similar models in literature, fast enough to be used in real time applications and proved to be adherent to the commercial simulator and actual operating data from Petrobras production systems.

Challenges and problems with advanced control and optimization technologies

Abstract Abstract Oil & Gas companies continuously try to create and increase business value of their installations (platforms, refineries, etc). Particularly the increasing energy consumption on a worldwide basis and, as a result, the substantial increase in prices volatility is a major drive for better advanced control and optimization technologies. Advanced control and optimization system can play an important role to improve the profitability and stability of industrial plants. This paper discusses the problems and challenges of advanced control and optimization in petroleum industries nowadays. It emphasizes the importance of control performance assessment technology to maintain a good regulatory control and the difficulties in using these technologies. It also shows the importance of malfunction detection and diagnosis advisory system for critical equipment in order to increase the operational reliability. Model predictive control (MPC) has become a standard multivariable control solution in the continuous process industries, but there are still many open issues related to accelerate a new implementation and maintain the controller with a good performance along the years. Real time optimization tools also impose new challenges for Oil & Gas industries application, which are discussed in this paper.

Intelligent system for start-up of a petroleum offshore platform.

It is difficult to control and to 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 qualitative operator and design knowledge can be easily implemented to assist the operator during start-up. This paper describes the integration of an expert system with a fuzzy controller applied to such a process. The intelligent system has many heuristic rules to implement the automation of the start-up procedures, like the opening of many on-off valves while simultaneously monitoring process variables. It also has a fuzzy controller to optimize the opening of the oil wells, in order to minimize the start-up time. This intelligent system is being implemented in the platform P-19 of Petrobras, the Brazilian oil company, in Campos Basin, Brazil. The prototype has been operating since October 1998.

Hybrid Monitoring of Offshore Compression Systems

Abstract In this work a hybrid methodology based on statistical approach and phenomenological modeling was developed aiming the monitoring of the performance of compression equipment in an offshore oil platform. A rigorous model was employed in order to estimate thermodynamic based values of the performance of the compression system, given by the polytropic efficiency and head. Residuals were generated by comparing the model values with the ones which were calculated from manufacturers curves using process data (suction and discharge pressures and temperatures, turbine rotation and suction flow). Even though the monitoring technique developed is essentially multivariable and dynamic, the results are displayed using typical univariate process control charts, providing a friendly interface for the operator and allowing the clear detection of process faults.

Advanced Control and Optimization of a Natural Gas Plant - Benefits of the New Regulatory Control Strategy

Abstract This paper presents the design of a new regulatory control strategy, as part of an advanced control and optmization project, for the natural gas processing plant of PETROBRAS (UPGN-III in Portuguese symbols) in Rio Grande do Norte. This phase of the implementation of the advanced control and optimization system (multivariable model based constraint control) allowed an increase of about 4% in the Liquefied Petroleum Gas (LPG) per charge and composition, this is the principal product of this unit, representing an income of US 1.300.000 a year. The new control system also reduced in 30% the number of unscheduled units downtime due to an improvement of its stability.

Challenges with Advanced Control Technologies

Abstract Model predictive control (MPC) has become a standard solution in the process industries, but there are still many open issues related to the acceleration of new implementations and the maintenance of good performance along the years. This paper will discuss some of these issues.

Evaluation of Control Structures for a Debutanizer Column

Abstract In this work is described the choice of the control structure for a specific industrial distillation column presenting a significant discrepancy between the inventories of the top and bottom sections. The studied distillation column showed to be an excellent research field, but looking for the balance between scientific development and industrial application it is always important to take into consideration the variable “time invested”. In this context, and searching for a satisfactory control structure, static analysis tools, as RGA and SVD, had been used in the characterization of a set of alternatives structures based on the primary composition control variables L, V, D and B, as well as some relations between them. With the reduction of the “time invested” kept in mind, it was used a rigorous dynamic simulator capable to deal with thermodynamic calculations for complex multicomponent mixtures, as those found in the processing units of crude oil and its fractions. Results have demonstrated the importance of rigorous dynamic simulation to solve design control problems in distillation columns which frequently presents unique characteristics and should be treated accordingly.