On the Reliability and Risk Analysis of Subsea Blowouts Preventers With Focused Attention on DP Rigs

Author(s):  
Nilo de Moura Jorge

This paper provides a selection of findings on the reliability and risk analysis of submarine blowout preventers (BOPs) achieved in recent studies, which the author has participated among technicians in Petrobras and Rio de Janeiro Federal University - UFRJ. Petrobras is a deepwater E&P leading company and special attention has been given on the deepwater and ultra deepwater scenarios. Particular factors on the BOP for dynamic positioning (DP) rigs need to be accounted as far as risks on safety and downtime are concerned. The analyses have considered a comprehensive BOP reliability database that covers more than 12 years of experience, as well as, a collection of DP experience has been accessed during work. The riser safety margin tends to be unavailable as the water depth becomes deeper, and, so, in an emergency disconnection, the safety isolation of the well tends to be relied on the BOP mechanical barriers only. In this context, risks on different configurations of the BOP are compared and their results discussed with focused attention on main factors of risk. Finally, there has been visible progress on BOP reliability within recent years and a number of good operational practices in place are also mentioned in the paper.

2019 ◽  
Vol 21 (2) ◽  
pp. 925-935
Author(s):  
Thais Dos Anjos Soares ◽  
Sinara Gomes De Souza ◽  
Simone Cardoso Ribeiro

Para compreensão da dinâmica do espaço natural, a Geografia Física possuiu inúmeras interdisciplinaridades que a acompanham, e a caracterização geoambiental é uma delas, no propósito de reconhecimento dos elementos constituintes da paisagem. O presente trabalho foca na caracterização geoambiental do município de Milagres, município do sul cearense, e teve como metodologia, pesquisa bibliográfica e cartográfica acerca dos elementos geoambientais da área de estudo, assim como a elaboração de material cartográfico utilizando os programas ArcGis e Qgis. Partindo desse material foi realizado uma breve descrição deste município, focando fundamentalmente nas características ambientais. É essencial o estudo da área em que irá realizar pesquisas, buscando o aprofundamento dos saberes de seus aspectos geoambientais para se obter uma prévia do conhecimento do local que irá ser trabalhado.Palavras-chave: Caracterização Geoambiental; Cariri cearense; Milagres/CE. ABSTRACTFor the dynamics of the natural space, a physical geography had numerous interdisciplinarities that accompany it, and a geoenvironmental characterization is one of them, without the purpose of recognition of the constituent elements of the landscape. The process of analysis of the processes of risk analysis and analysis of the morphosculpture processes and their use in the soil and in the health and sciences / EC systems, which studies the thematic knowledge of geomorphological processes considering the knowledge about nature and values of culture and local landscape, however, the geoenvironmental characterization work of the municipality of Milagres / CE. The work had as a methodological objective, bibliographical research and the translation of the geoenvironmental elements of the study area. For this work, cartographic material was elaborated using the programs ArcGis and Qgis. Starting from this material was a detailed description of its area of study, as well as one of its environmental characteristics. What is essential for the selection of geoenvironmental data to obtain a preview of the knowledge about the work place that will be realized.Keywords: Geoenvironmental Characterization; Cariri cearense; Milagres/CE. RESUMENPara comprender la dinámica del espacio natural, la Geografía Física tiene numerosas interdisciplinarías que la acompañan, y la caracterización geoambiental es una de ellas, para reconocer los elementos constitutivos del paisaje. El presente trabajo se centra en la caracterización geoambiental del municipio de Milagres, municipio de sul cearense, y tuvo como metodología, investigación bibliográfica y cartográfica sobre los elementos geoambientales del área de estudio, así como la elaboración de material cartográfico utilizando los programas ArcGis y Qgis. A partir de este material se realizó una breve descripción de este municipio, centrándose principalmente en las características ambientales. Es esencial estudiar el área en la que realizar investigaciones, buscando profundizar el conocimiento de sus aspectos geoambientales para obtener un conocimiento previo del lugar donde se trabajará.Palabras clave: caracterización geoambiental; Cariri Ceará; Milagros / CE.


2020 ◽  
Vol 3 (SI1) ◽  
pp. SI151-SI156
Author(s):  
Le Khanh Tan ◽  
Tran Ngoc Huy ◽  
Pham Huy Hoang

Autonomous underwater vehicle (AUV) known, as a special purpose underwater research vehicle (SPURV) is really a pocket submarine that could be used in multipurpose such as meteorology, probing the pollution of stream, military spying, exploring an underwater tunnel or wrecked ships and other purposes. With the reason of the power of battery inside of AUV is limited, the aim of this paper is to represent an effect way of control the submerging and surfacing of an AUV in order to save energy for a longer time service or a deeper and further expedition under water. In fact, there are so many ways for saving energy of the battery of AUV and in this paper, the selection of keeping permanently the horizontal direction of the AUV in any operation as the situation of a real submarine is applied. The diving and surfacing of AUV are consigned to the motor of the pump that consumes a little of energy to keep the proportion of the weight and the Archimedes force by pumping water inside or outside of the AUV. The selection of volume of pumped water is considered as a dynamic ballast mass for maintaining the horizontal equilibrium of the AUV at the time of submerging and surfacing. In the other hand, the controlling of the gravity point of AUV for maintaining a fixed position of gravity of the AUV when submerging and surfacing are the main factors of the paper that is also investigated in this paper. Finally, the motor of the propeller or thruster that always spends a great energy has committed only for forward or backward motion of the AUV. In this measure, the motor of thruster does not confronted with a great consummation of energy when submerging and surfacing in an oblique direction as almost all popular measures of control of AUV.


2020 ◽  
Vol 136 ◽  
pp. e171-e180
Author(s):  
Yaobin Li ◽  
Hao Bai ◽  
Chenxin Liu ◽  
Yan Zhao ◽  
Yafei Feng ◽  
...  

2013 ◽  
Vol 475-476 ◽  
pp. 598-602
Author(s):  
Xiao Lu Su

In fuzzy system, the selection of fuzzy rules is difficult. For the whole system, the merits of the rules seriously influence the final result. This paper uses the ant colony algorithm (ACA) to optimize the weights of the rules in the standard additive fuzzy system. At present, the ship dynamic positioning system has caused wide public concern. In the paper, a ship dynamic positioning controller based on the ACA and the standard additive model is proposed. Through the new controller is applied to control the dynamic positioning ship in the complex sea conditions, the results show that the proposed controller is effective.


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