Excess global elemental sulphur (So) production has resulted in a decrease in its price. As a result, many companies, such as Syncrude Canada Ltd., have resorted to above ground storage alternatives. Geochemical reactions in these above ground blocks produce elevated concentrations of H2SO4 (acid). This acid can have potentially deleterious effects on the environment. As such, these blocks will require long-term (500 years) monitoring and maintenance. Presently the So is removed from the product stream, piped in a molten state, and poured over a low permeability liner in thin lifts. As the So cools and undergoes crystal structure change it fractures, creating preferential flow passages which are potentially highly conductive. An understanding of the liquid conductivity (Kl) of the block and knowledge regarding the spatial and temporal distribution of acid (H2SO4) within these blocks is required. In this thesis, gas pumping tests were conducted on an above ground block to determine the gas flow rates within the block and to indirectly determine the Kl of the block. Measurements of the relative humidity (RH) in the block were used to observe changes in stored acid concentrations with time and location. The results of the gas conductivity (Kg) testing showed that the block is anisotropic and is highly conductive in both the horizontal and vertical directions. Cross hole tests appeared to produce the most representative estimates of Kg due to the negation of turbulence that arises in the vicinity of the borehole. The choice of gas used in the analysis had negligible effect on the resulting Kl in contrast to choice of liquid, which resulted in larger variations in Kl. The Kl was a maximum when the liquid was pure water and decreased with increasing acid strength. The geometric mean of the resulting cross hole Kl values was 2 x 10-3 m s-1 (pure water). RH measurements were observed to fluctuate with depth and increased following precipitation. The resulting minimum pH observed within the block occurred at depths of 3 and 7 meters below the surface of the So block and increased with depth. The arithmetic mean pH value based on the daily averaged RH measurements was -1.7.

[pt] Um sistema de produção e escoamento de petróleo, quando equipado com manifold submarino, viabiliza a produção conjunta de poços de diferentes capacidades de produção. O equilíbrio conseguido na produção desses poços se faz à custa do estrangulamento (choking) dos poços de mais alta capacidade de produção, de forma a propiciar um equilíbrio com aqueles de mais baixa capacidade de produção. Naturalmente as vazões atingidas nessa forma sinérgica são menores do que aquelas que seriam atingidas com a produção em separado desses poços mas, tais menores vazões são economicamente mais atraentes devido às economias atingidas nos custos de investimento (e.g., redução do comprimento total de linhas de produção e do número de risers) e das esperadas e normalmente ocorrentes reduções de custo operacional nesses sistemas. Entretanto, a partir da disponibilidade da tecnologia de bombeamento multifásico submarino, na qual se torna possível diretamente transferir energia à misturas multifásicas (óleo, gás e água) em produção, viabiliza-se o estabelecimento de um novo e mais atraente tipo de equilíbrio nesses sistemas. Tal novo equilíbrio, possível pelo uso de sistemas de bombeamento multifásico instalados em manifold submarinos de produção, deve propiciar níveis de produção governados inclusive pelos limites impostos pela engenharia de reservatórios e não mais tão somente pelas características físicas dos sistemas (seções de escoamento, distâncias, lâminas d`água, propriedades dos fluidos etc.). A esta forma inédita de obtenção de um novo e mais alto patamar de equilíbrio da produção, a literatura vem utilizando a denominação Estrangulamento Positivo (Positive Choking). Assim, baseados no aumento das vazões de produção - antecipação de produção - e no potencial aumento dos fatores de recuperação - maiores volumes produzidos - acredita-se ser tal técnica economicamente atraente quando aplicada em sistemas de produção ainda em implementação, ou mesmo, na implantação da mesma em sistemas já instalados. O propósito desta tese é o de contribuir na análise técnica e econômica da inédita aplicação de um sistema de bombeamento multifásico submarino num sistema de produção equipado com manifold. / [en] A subsea oil production system allows simultaneous production of several wells with different flow rates when the system has a subsea manifold. In order to balance the different flow rates, the higher production wells have their flow rates reduced via a choking system. As a result, the total flow is lower than the summmation of all individual well flow rates. But, this combined and lower production has a very attractive economics, as it requires lower capital expenditures, mainly due to the shorter overall length of flowlines and lower number of risers and, also due to the expected lower operational costs. Nowadays, however, with the availabity of the technology of subsea multiphase pumping system, which enables the transfer of energy to multiphase mixtures (oil, gas and water) under production, becomes possible to achieve an even higher and more attractive plateau in these petroleum production systems. This new equilibrium plateau, made possible by the technology of subsea multiphase pumping, will lead to production levels that will attempt to take benefit of all reservoir allowance and then extending the primary production limit imposed by the production system characteris tics (e.g., flowline length, water depth, produced fluid properties etc.). This novel scheme that allows obtaining a now and higher production level is being called in the literature as Positive Choking. Therefore, based on the resultant aspects of production flow rate increase - production anticipation - and on the potentially higher recovery factors - larger produced volumes - is what drives the belief that such technology can be economically attractive to new production systems being installed or even in those already in operation. The purpose of this work is to contribute in the technical and economical evaluation of Multiphase Pumping System application on a subsea production system equipped with a manifold.

Increasingly growing consumption of natural gas all around the world requires development of new transporting equipment and optimization of existing pipelines and gas pumping facilities. As a special case, Russian gas pumping system has the longest pipes with large diameter, which carry great amounts of natural gas. So, as reconstruction and modernization needs large investments, a need of more effective and low cost tool appeared. As a result diagnostics became the most wide-spread method for lifecycle assessment, and lifecycle extension for gas pumping units and pipelines.One of the most effective method for diagnostics of gas pumping units is parametric diagnostics. It is based on evaluation of measurement of several termo-gas dynamic parameters of gas pumping units, such as pressures, temperatures and rotational speed of turbines and compressors.In my work I developed and examined a special case of parametric diagnostics – methodic for evaluation of technical state and output parameters for gas pumping unit “Ural-16”. My work contains detailed analysis of various defects, classified by different GPU’s systems. The results of this analysis are later used in development of the methodic for calculation of output parameters for gas pumping unit.GPU is an extremely complex object for diagnostics. Around 200 combinations of Gas Turbine engines with centrifugal superchargers, different operational conditions and other aspects require development of separate methodic almost for each gas pumping unit type.Development of each methodic is a complex work which requires gathering of all possible parametric and statistical data for the examined gas pumping unit. Also parameters of compressed gas are measured. Thus as a result a number of equations are formed which finally allow to calculate such parameters as efficiency, fuel gas consumption and technical state coefficient which couldn’t be measured directly by existing measuring equipment installed on the gas compressor station.