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Risk assessment has always been the most challenging part of the risk management process for aviation operations. This paper investigates the risks involved in the Tripoli and Mitiga International Airport in Tripoli, Libya. This case study addresses the risks that may occur during aircraft flight operations. It also investigates the human performance during the ground and flight operations. The paper implements some countermeasures in order to avoid and/or eliminate the risks, and to make sure that all risks remain at an acceptable level.The results demonstrated that a 67.9% of the registered risks are operational risks, 10.7% of the recorded risks are personal risks, 3.6% are health and safety risks, another 3.6% are strategic risks, 7.1% are financial risks, and another 7.1% are technical risks. Besides, the most of the countermeasures which suggested as solutions are suitable and beneficial. Moreover, implementation of the safety management system are effectively reduced the cost and improved the efficiency of the business.

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Several published correlations used to estimate the bubblepoint pressure and the bubblepoint oil formation volume factor of reservoir oils require that the value of the bubblepoint solution gas/oil ratio be one of the input variables. Consequently, engineers resort to an additional correlation in order to estimate this value. The majority of the published bubblepoint solution gas/oil ratio correlations are functions of bubblepoint pressure and gas gravity, which can be obtained either experimentally (pressure-volumetemperature, PVT analysis) or estimated from the existing correlations. Thus, it is difficult to apply the correlations in the absence of a PVT analysis. In this study, a multiple regression analysis technique was applied to develop two novel correlations to estimate the bubblepoint solution gas/oil ratio and stocktank vent gas/oil ratio in the absence of a PVT analysis. The developed correlations can be directly applied by using readily available field data, thus, forgoing the requirement of additional correlations or a PVT analysis. The bubblepoint solution gas/oil ratio correlation is related to the separator gas-oil ratio, to the separator pressure, and to the stock-tank oil specific gravity. However, separator pressure and temperature with the stock-tank oil specific gravity were the only independent variables used in stocktank vent gas/oil ratio correlation. Another additional and important application of the proposed stocktank vent gas/oil ratio correlation was to estimate the stock-tank vent gas flow rate.

Up till now, there has not been one specific correlation published to directly estimate the bubblepoint pressure in the absence of PVT analysis and, at the moment, there is just one published correlation available to estimate the bubblepoint oil FVF directly in the absence of PVT analysis. The majority of the published bubblepoint pressure and bubblepoint oil FVF correlations cannot be applied directly. This is because the correlations require the knowledge of bubblepoint solution GOR and gas specific gravity as part of the input variables, both of which are rarely measured field parameters. Solution GOR and gas specific gravity can be obtained either experimentally or estimated from correlations. In this study, multiple regression analysis technique is applied in order to develop two novel correlations with which to estimate the bubblepoint pressure and the bubblepoint oil FVF. These new correlations can be applied in a straightforward manner by using direct field data. Additional correlations or experimental analyses are unnecessary. Separator GOR, separator pressure, stock-tank oil gravity and reservoir temperature are the only key parameters required to predict bubblepoint pressure and bubblepoint oil FVF using the proposed correlations. IntroductionReservoir fluid studies are essentially based on pressure-volume-temperature (PVT) analysis. This analysis consists of a series of laboratory procedures designed to provide the values of the reservoir fluid properties required in material balance calculations, well test analysis, reserves estimates, inflow performance calculations, and numerical reservoir simulation. Ideally, reservoir fluid properties are determined from laboratory studies on live oil samples collected from the bottom of the wellbore or from the surface. Standard reservoir PVT fluid studies are designed to simulate the simultaneous fluid flow of oil and gas from the reservoir to the surface. The production path of reservoir fluids from the reservoir to surface is simulated in the laboratory at reservoir temperature. During this process, the bubblepoint pressure (p b ) is measured. Likewise, the oil volumes and the amount of gas released are measured and used to determine oil FVF (B o ) and solution GOR (R s ) as functions of pressure.