bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Improvement of a Semi-Coupled Analysis for a Turret Moored FPSO in Deep Water
Authors: Xu Z. , Anderson K. 
Published: October 2015

A fully-coupled method is deemed desirable for global response analyses of deep water floating structures. However, even with ever increasing computing power, the fully-coupled method is still time consuming, especially when a large number of different load cases need to be considered. In contrast, the computational cost is much lower for a semi-coupled method at the expense of analytical accuracy. The benefits of a fully-coupled method include taking into account the coupling effects between damping due to the slender structures and motions of the FPSO. Previous studies have indicated that the total damping can be significantly influenced by the mooring line damping. The semi-coupled method can be improved if this damping effect is properly modelled and included.
It is known from previous studies that mooring line damping can be significantly increased by wave-frequency (WF) motions. However, typically only harmonic WF motions were considered in these studies. In this paper, the effect of random WF motions on mooring line damping is investigated. It is found that, statistically, the effect of random WF motions on the mooring line damping can be represented by an equivalent harmonic WF motion. Based on this, the mooring line damping can be estimated and used in the semi-coupled analysis. A comparison of the semi-coupled method with a fully-coupled method is made by performing a global analysis of a turret moored FPSO under an extreme sea-state with a 100-year return period. It is shown that with the system damping properly estimated, the excursion results of the moored FPSO by the semi-coupled method are in very good agreement with those obtained by the use of the fully-coupled method.
Challenges in Offshore Natural Gas Processing
Authors: Bidart Antônio Marcos F. , de Melo Darley Carrijo , Passarelli Fábio Menezes , Nascimento Jailton Ferreira do , Silva Juliana Pereira , Andrade Leandro D. Sampaio , Pereira Leonardo dos Santos , de Rezende Tapajos Leticia , Grava Wilson Mantovani 
Published: October 2015

The Brazilian offshore pre-salt cluster is one of the most important recent discoveries of hydrocarbon resources in the world. These fields normally present high CO2 content (more than 10%) and also high Gas Oil Ratio (GOR), thus might limit the oil production in the convention FPSOs project due to the capacity and complexity of gas processing plant. These conditions lead to application of alternative processes for gas treatment in offshore environment, such as molecular sieve for dehydration, fixed bed for H2S removal and CO2 removal membranes. Besides, due to high flow and high pressure drop involved in the treatment section, an increase in the number of equipment, such as compressors, heat exchangers and scrubbers are needed in order to reach high pressure values necessary for the CO2 reinjection into production zones for Enhanced Oil Recovery (EOR). proposes.
This objective will also contribute to increase complexity on the gas processing plant since it must deal with expected variations in GOR and CO2 content in natural gas during field lifetime. Petrobras and partners have been working, since 2008, with the objective to increase performance of existing processing and compression technologies and also supporting application of new ones (technological gaps) that can result in overall improvements in CAPEX and OPEX, such as: nano-sized zeolites for dehydration, new metal oxides for H2S removal with high capacity under influence of CO2, new material for membranes (ceramic and carbon tubes) and dense phase CO2 separation. The aim of the combined use of such iniatives is footprint and weight reduction, higher efficiency, less energy consumption with modular design. The purpose of this paper is to present the actual strategy for developing offshore gas process in Brazil, emphasizing the different technological gaps identified and the consequential road maps that are being pursued for the new units to be designed.
Hybrid Cellular Tendon Design for TLP in Ultra-Deep Water
Authors: Yu Jim , Wu Chunfa , Heidari Homayoun , Zhao Rex 
Published: October 2015

Cellular tendon design expands the envelope of water depth and payload on TLPs and enables their use for ultra-deepwater developments as well as production hubs. Cellular tendon design was initially introduced to the industry at OTC Brazil 2013 where its design elements and features along with the corresponding feasibility assessments were presented. For the initial development of the Cellular Tendons, the fabrication and installation were based on onshore assembly and tow-out of the full-length tendons to the installation site. This design was developed mainly for installation sites where a nearby fabrication yard with open water access is available. This design is especially suitable for developments in areas with local content requirements, where a significant amount of investment can be made in local yards for fabrication and assembly of the tendons.
In order to accommodate current standard industry practice for fabrication and installation of the tendons, an alternative design to the full-length cellular tendon has been developed. This alternative design, named the Hybrid Cellular Tendon, employs the same tendon transportation and installation methods as for the conventional tendons. The hybrid cellular tendon can be fabricated in any of the existing tendon fabrication yards and can be installed by any of the current tendon installation vessels.
This paper presents design of the general system and component of the Hybrid Cellular Tendon. The paper demonstrates that performance of the Hybrid Cellular Tendon satisfies the ultra-deep water TLP requirements while providing advantages over that of the conventional tendons for TLPs as hubs with large payloads. The construction and installation of the Hybrid Cellular Tendon, which are well within the current industry's capability and practices, are discussed as part of the design in the paper. The Hybrid Cellular Tendon design further proves the feasibility of cellular tendons in enabling TLP applications in ultra-deep waters and /or with large payloads.
A New Methodology for the KG Estimation of a Semisubmersible in Service
Authors: Porciuncula I. N. , de Tarso Themistocles Esperança P. , Castillo C. A. Rodrçguez 
Published: October 2015

This work presents a new methodology for the estimation of the vertical center of gravity (KG) of an offshore semisubmersible oil production unit. There are a lot of stationary semisubmersible (SS) production units that have been working offshore for 20 years or more and some of these units have received a lot of lightweight modifications to comply production improvements, affecting its KG position. Most of them do not have all documentation available and the costs involved in bringing these units onshore to perform a conventional inclining test are so high that makes this option unviable. Some production semisubmersibles still need more equipment and structures to increase their oil production, i.e., deck load capacity that affects the KG which is a limited mandatory variable.
The methodology developed for finding the KG states that it is perfectly possible to identify a unique hydrodynamic behavior around the neutral stability, where the metacentric height (GMT) equals to zero. Under this condition, the KG gets the same value of the transverse metacenter height (KMT), which is a known parameter that only depends on the underwater hull geometry.
A 1:50 scale model of a semisubmersible was built in order to assess the influence of mooring lines and waves on the method's accuracy. The model tests, performed at LabOceano – Ocean Technology Tank of Coppe/UFRJ, revealed very low influence of waves and mooring lines in the methodology accuracy even in waves of different heights and directions. Numerical computations considering hydrostatic properties and hydrodynamic loads in regular seas indicated the same results observed in the model tests. A hydrostatic comparison between the conventional inclining test method and this new neutral stability method has presented very similar results.
Applying Big Data Analytics to Logistics Processes of Oil and Gas Exploration and Production Through a Hybrid Modeling and Simulation Approach
Authors: Sousa C. J. N. , Santos I. H. F. , Almeida V. T. , Almeida A. R. , Silva G. M. , Ciarlini A. E. , Prado A. , Senra R. D. A. , Gottin V. , Bhaya A. , Calmon T. , Ferreira L. 
Published: October 2015

The exploration and production of oil and gas lead to many logistics challenges. In the case of the Brazilian offshore production, the operation size and the fact that the exploration occurs up to 300 km apart from the coast make these challenges even greater. There are many thousands of different types of materials, hundreds of suppliers, as well as hundreds of different destinations served by distinct routes. In short, this is a complex system, in which it is necessary to deal with an intrinsically combinatorial problem of sharing resources, such as warehouses, ports and means of transportation. Logistics processes need to deliver the materials in time, making sure that the production is not affected.
In addition, operational costs and immobilized capital must be minimized. It is crucial to evaluate distribution probabilities for lead-times, identify bottlenecks and predict the effect of adopting specific policies for supply, picking and transportation. In order to address these issues, it is necessary to answer complex what-if queries that take into account the temporal relations, either specified or dictated by the process dynamics, between the events.
Since all operations are logged, a substantial amount of historical data is generated. However, these data do not necessarily cover all situations, simply because certain feasible and relevant combinations of events may not have occurred during the period that data is logged. This motivates the use of simulations that generate huge amounts of data augmenting the (logged) historical data, and making big data analytics necessary. In this paper, we briefly describe the process of model building based on historical data as well as the construction of a simulation engine that permits efficient large scale simulations. The simulation results, together with the logged historical data are subjected to big data analytics in order to create global prediction models.
The proposed methodology aims to answer complex what-if queries about the logistics processes with a high degree of efficiency and prediction accuracy. The software tool, based on this methodology, is designed so that a decision maker can interactively detect critical situations and study the global effect of changes in policies. Some examples of queries that can be supported by this research are: (i) estimation of distribution probabilities for lead-times under varied circumstances; and (ii) probability of critical materials shortage during periods of high demand.
Regulatory Environment and Endogenous Technological Development in the Upstream Oil and Gas Industry in Brazil
Authors: Mancini L. 
Published: October 2015

Since its formal creation in 1953, Petrobras has operated in monopoly in the Oil and Gas (O&G) industry in Brazil. In 1997, the Congress approved the law 9478/1997 (Petroleum Law), which set a fundamental change in the legal framework and allowed other competitors to enter into the market. Since then, the government has also implemented a set of new regulations in the O&G sector to foster local content as well as investments in science, technology and innovation. Here we aim to understand how the regulatory environment affects technological development in the upstream O&G industry.
Our methodology consists of two pillars. First, we provide a critical review of the literature about the broad relation between natural resources and economic development. We find that technological development is a key driver of productive linkages from the primary sector and we suggest that the regulatory environment plays a major role. Second, we adopt both quantitative and qualitative methods to analyze three specific mechanisms of the regulatory framework for the case of Brazil.
Our results are two-fold. On one hand, the regulatory environment has prompted significant investments in science, technology and innovation in the O&G industry; also, it has promoted the establishment of new partnerships between the oil industry and the Science and Technology Institutions (STIs). On the other hand, some regulations as well as recent modifications have hampered investments in science and technology, especially due to a low involvement of the suppliers. An important conclusion is that, for the case of Brazil, the R&D center Petrobras has played a leading role in fostering technological development. Though, the regulatory environment needs to be revised to involve more actors in this process; more coherent and coordinated policies are needed to promote both local content and innovation at the same time.
This paper differs from previous literature in two key aspects. First, whereas other scholars tend to study the macroeconomic and governance-related issues of natural resources, here we analyze their productive implications. Second, our work combines both quantitative and qualitative research methods; both questionnaires and semi-structured interviews have allowed us to collect primary data at micro-level.
Advanced Microstructural Characterization of a X-70 Microalloyed Steel for the Oil and Gas Industry
Authors: Berlanga I. , Bruna R. , Perez T. , Garcia I. 
Published: October 2015

Abstract
Continuous energy developments around the world provide both an opportunity and challenge to develop linepipe microalloyed steels with superior properties and performance for the oil and gas industry. To fulfill these requirements a fundamental understanding of the composition-processing-microstructure-property relationship is needed. The objective of the present work was to define the optimal microstructure to achieve the required strength-toughness properties.
Different thermodynamic software packages and mean flow stress (MFS) models were used to study the effect of the composition and thermomechanical processing (TMP) conditions on the final microstructure.
The validation stages were performed by laboratory studies and industrial scale trials. Impact tests were used to evaluate the toughness. Advanced characterization techniques; electron optics (SEM, HRTEM) and Electron-Backscattered Diffraction (EBSD) microstructural analysis were carried out to quantify the microstructure, texture, precipitation and the evaluation of crack propagation paths.
The X-70 microalloyed steel exhibited an excellent package of strength-toughness properties. These properties were obtained by a combination of fine bainitic ferrite, fine precipitations and small volume fraction of fine MA islands. The fine bainitic ferrite was the result of the microstructural conditioning of the austenite prior to the transformation and cooling conditions. It provided excellent resistance to crack propagation.
Gas-to-Liquid Technology Off-shore
Authors: Claridge Tais Bjerg 
Published: October 2015

Topsoe has recently been awarded a 15,500 barrels per day gasoline plant in Turkmenistan. Here the gasoline is produced from natural gas via methanol. By commercialization of this gas-to-liquid technology on-shore, we have established the foundation for taking the technology off-shore with all its considerations to marinization, space limitations and choice of technology solutions that are acceptable not only from an operational point of view but also from a safety point of view.
The possibility to produce a liquid fuel from the associated gas is highly desirable in many locations, especially if it can utilize the already established logistic set-up. Considering the increasing effort to reduce or even limit by legislation the allowable flaring rate, it is highly desirable to convert the associated gas to a liquid. By producing a liquid fuel from the associated gas, the flaring no longer becomes the limitations to the crude oil production rate. Furthermore, in other locations, the need for gasoline produced directly on the vessel can be an attractive solution if local demand for gasoline is provided by import of gasoline.
This paper will describe the considerations behind the selected technology steps for the Topsoe TIGAS solution, the merits of its application and present a case study for TIGAS applied off-shore.
The Importance of Extra-Deep Azimuthal Resistivity in Reservoir Development: An Update on Recent Field Experiences
Authors: Tilsley-Baker R. , Hartmann A. , Sviridov M. , Sanabria O. , Skillings J. , Kjølleberg M. , Barbosa J. E. , Loures L. , Pearson P. Swalf , Morani B. 
Published: October 2015

Abstract
Extra-deep reading azimuthal resistivity tools have been deployed in various reservoir settings around the world in recent years in an effort to further improve efficiencies in reservoir development. For many years field development relied on standard and azimuthal propagation resistivity tools with depths of investigation up to approximately 5m, contributing to optimized and pro-active geosteering. While effective at geosteering against adjacent boundaries to maintain position in oil bearing formation, more complex reservoir architectures require data sensing further into the formation to allow a closer correlation with seismic models and provide more complete reservoir mapping.
The first extra-deep propagation resistivity tools were developed by employing lower frequency waves, increasing antenna spacing and eventually adding lower frequency azimuthal signals. The new designs greatly increased the depth of detection and also added directional components. However, due to the greater volume of formation being investigated, the deeper readings bring extra complexity and uncertainty to the interpretation process so that innovative inversion software is required to support the tools and produce results that can be used in real-time.
The inversion method described in this paper for the interpretation of extra-deep azimuthal resistivities employs a-priori constraints and is user-controlled in order to accurately monitor laterally and vertically changing geology. The examples shown here will demonstrate how inversion results based on a full suite of resistivity measurements have brought benefits to reservoir understanding by deriving sandstone thickness, detecting multiple bed boundaries, locating remote sandstones and remote resistivity plus the relative dip between the tool and the formation. The integration of this data results in better constrained reservoir models and an improved field development strategy.
This paper will present the results of wells drilled using extra-deep azimuthal resistivity tools on the Peregrino Field in Brazil. The reservoir comprises complex high energy gravity flows consisting of reservoir units difficult to map due to being below seismic resolution. The sandstones have limited lateral extent and thicknesses ranging from 2m to 25m. Originally developed to improve net sandstone drilled in the Peregrino heavy oil reservoir by allowing a more strategic approach to geosteering, the tool deployment has brought additional benefits in reservoir understanding which impact seismic model interpretation, future well planning, completion strategies and reduce the need of pilot holes.
Pipe-in-Pipe Riser Solution for FPSO’s Offshore Brazil
Authors: de B. Daly J. R. , Saraiva T. C. , Bhat S. U. , Dong J. , Mansour A. M. 
Published: October 2015

As part of an early ultradeep water field development study for offshore Brazil, the extreme dynamic responses of various compliant steel riser configurations; Steel Catenary Riser (SCR), Shaped-SCR (SSCR) and Steel Lazy Wave Riser (SLWR), are investigated in combination with Floating Production Storage and Offloading units (FPSOs) and Semisubmerible Floating Production Units (SEMI FPUs). As part of this investigation, the feasiblity of Pipe-in-Pipe (PIP) SCR design when hosted on FPSO offshore Brazil is explored which, if successful, enables a simpler and more cost effective configuration with improved flow assurance capabilities.
Several FPSOs and Semis are designed and vessel motion screening results used to identify potentially feasible riser porch hang-off locations along the side of the different hull types and sizes under consideration. A relationship between pipe terminal velocity and riser’s Maximum Allowable vertical Velocity (MAV) at the riser porch is developed to predict an acceptable limit against overstressing at the Touch Down Point (TDP) for a range of pipe sizes and configurations, under extreme wave loading conditions. Both near and far cases are analysed.
Preliminary wave fatigue loading analyses are then performed for the most promising configurations. A Rainflow cycle counting method is used to compute the fatigue damage.
Riser behaviour is highly influenced by the insulation applied. For FPSOs, it is found that uninsulated heavy walled SCRs are feasible with respect to strength for some porch locations, whereas insulated SCRs are not feasible. PIP SCRs are found to exhibit superior strength behaviour, mitigating the normally limiting compression buckling phenomena in the TDP, enabling this concept in deepwater. Fatigue life assessment on the other hand, shows the PIP SCR will not work without further development of specific fatigue life enhancement solutions. As an option, a considerably reduced amount of buoyancy can potentially make the PIP riser work, in a so called Shaped SCR (SSCR) configuration.
Other technical qualification gaps to meet PIP SCR strength and fatigue requirements are identified and discussed.
A Model for the Valuation of an Inspection Program in Offshore Oil Production Facility
Authors: Lima Gabriel A. Costa , Teodoro Filho Alberto M. 
Published: October 2015

In the operation of offshore O&G there is a large number of equipment that must work continuously to keep production and safety. Part of this success depends on different type of inspection activities in active and redundant equipment. However, there are some conflicting objectives: the more one inspect equipment, the higher the reliability of the system. At the same time, cost can be increased and availability reduced in case assets have to stop. In addition, more sophisticated inspection systems have a cost and, also may demand maintenance in the instrumentation.
The present work proposes a model to evaluate this problem. The methodology is: (1) Probabilistic model of time-to-failure of assets, (2) Probabilistic model of maintenance time, (3) Probability model of the detection of failure by inspection, (4) Reliability and Availability model of the system, (5)Inflation in cost of part, labor, etc., (6) Discounted cash flow model. We use Monte Carlo simulation in order to solve this problem in a simple spreadsheet in order to demonstrate professionals that many problems can be scientifically analyzed using more simple tools.
In real world applications, the main problem consists in the estimation of the value of an inspection system to a company. We apply the model of this paper to the analysis of this problem and find the following conclusions: If probability of detection of the inspection system is 90%, the maximum investment is US$ 12.2 million; if this probability of detection is 70%, the maximum investment is US$ 9.65 million. In addition, the work will show how to use the model to solve related problems as well.