Estudo de estratégias de otimização para poços de petróleo com elevação por bombeio de cavidades progressivas

The progressing cavity pump artificial lift system, PCP, is a main lift system used in oil production industry. As this artificial lift application grows the knowledge of it s dynamics behavior, the application of automatic control and the developing of equipment selection design specialist systems are more useful. This work presents tools for dynamic analysis, control technics and a specialist system for selecting lift equipments for this artificial lift technology. The PCP artificial lift system consists of a progressing cavity pump installed downhole in the production tubing edge. The pump consists of two parts, a stator and a rotor, and is set in motion by the rotation of the rotor transmitted through a rod string installed in the tubing. The surface equipment generates and transmits the rotation to the rod string. First, is presented the developing of a complete mathematical dynamic model of PCP system. This model is simplified for use in several conditions, including steady state for sizing PCP equipments, like pump, rod string and drive head. This model is used to implement a computer simulator able to help in system analysis and to operates as a well with a controller and allows testing and developing of control algorithms. The next developing applies control technics to PCP system to optimize pumping velocity to achieve productivity and durability of downhole components. The mathematical model is linearized to apply conventional control technics including observability and controllability of the system and develop design rules for PI controller. Stability conditions are stated for operation point of the system. A fuzzy rule-based control system are developed from a PI controller using a inference machine based on Mandami operators. The fuzzy logic is applied to develop a specialist system that selects PCP equipments too. The developed technics to simulate and the linearized model was used in an actual well where a control system is installed. This control system consists of a pump intake pressure sensor, an industrial controller and a variable speed drive. The PI control was applied and fuzzy controller was applied to optimize simulated and actual well operation and the results was compared. The simulated and actual open loop response was compared to validate simulation. A case study was accomplished to validate equipment selection specialist system

Monitoramento em tempo real de processos fermentativos por espectroscopia no infravermelho próximo (NIRS)

A chemical process optimization and control is strongly correlated with the quantity of information can be obtained from the system. In biotechnological processes, where the transforming agent is a cell, many variables can interfere in the process, leading to changes in the microorganism metabolism and affecting the quantity and quality of final product. Therefore, the continuously monitoring of the variables that interfere in the bioprocess, is crucial to be able to act on certain variables of the system, keeping it under desirable operational conditions and control. In general, during a fermentation process, the analysis of important parameters such as substrate, product and cells concentration, is done off-line, requiring sampling, pretreatment and analytical procedures. Therefore, this steps require a significant run time and the use of high purity chemical reagents to be done. In order to implement a real time monitoring system for a benchtop bioreactor, these study was conducted in two steps: (i) The development of a software that presents a communication interface between bioreactor and computer based on data acquisition and process variables data recording, that are pH, temperature, dissolved oxygen, level, foam level, agitation frequency and the input setpoints of the operational parameters of the bioreactor control unit; (ii) The development of an analytical method using near-infrared spectroscopy (NIRS) in order to enable substrate, products and cells concentration monitoring during a fermentation process for ethanol production using the yeast Saccharomyces cerevisiae. Three fermentation runs were conducted (F1, F2 and F3) that were monitored by NIRS and subsequent sampling for analytical characterization. The data obtained were used for calibration and validation, where pre-treatments combined or not with smoothing filters were applied to spectrum data. The most satisfactory results were obtained when the calibration models were constructed from real samples of culture medium removed from the fermentation assays F1, F2 and F3, showing that the analytical method based on NIRS can be used as a fast and effective method to quantify cells, substrate and products concentration what enables the implementation of insitu real time monitoring of fermentation processes

Abordagem da ergonomia para avaliação do treinamento simulado das equipes de resposta à emergência em lançamentos de veículos aeroespaciais

This dissertation introduces a study that aims to analyze the simulated training of emergency teams and proposes recommendations for the current training system in order to improve the collective skills and resilience of these teams when facing possible critical situations, triggered by possible accident occurrences during aerospace vehicle launching operations in the Barreira do Inferno Launch Center in Parnamirim / RN. This is a field, exploratory, descriptive, explanatory, and a case study with a qualitative approach. Therefore, we adopted the ergonomics approach, using the situated method of ergonomic work analysis (AET), combining observational and interactive methods. The relevance of this research is characterized by the contributions to minimize the human and material hazzards resulting from possible accidents in these operations, the scientific contribution of the AET for simulated emergency training analysis in the launching operations of aerospace vehicles - which are complex and involve risk of accidents - and consequently, the scientific contribution to the current process of recovering the Brazilian Space Program. The survey results point to problems of various kinds in the current simulated training system which compromise the safety of the operations. These problems are grouped into four categories: technological, organizational, team training and from the activity itself, regarding more specifically communication and cooperation (among the team members and these ones with other sectors involved in the launching operation) and regarding the coordination of actions. We propose: a) a new training model, from the creation and application of scenarios based on postulated abnormalities, which could simulate real critical situations, in order to train and improve the skills of the emergency response teams especially in terms of communication, coordination and cooperation; b) restructuring and reorganizing the current training system, based on the formal establishment of a managing staff, on the clear division of responsibilities, on the standardization of processes, on the production of management indicators, on the continuous monitoring, on the feedback from trainees about the quality of the training and on the continuing and frequent training of emergency teams.