Esteves, V. P. P. (Federal University of Rio de Janeiro) | Wanke, B. S. L. (Federal University of Rio de Janeiro) | D'Avila, C. J. R. (Federal University of Rio de Janeiro) | de Mello, C. S. B. (Petrobras) | Grava, W. M. (Petrobras) | McLean, S. (Ocean Networks Canada)
In the deep water pre salt Santos Basin Petrobras is interested in potential monitoring technologies for detection of carbon dioxide (CO2) in seawater at depths between 1200 and 2600 meters. At these depths, CO2 is not a gas but a buoyant liquid with densities similar to sea water, which makes detection challenging. Also potentially present with CO2 is methane (CH4), which at these depths is close to liquid-hydrate combination, which may possibly cause interference with some measurement techniques used for CO2.
The Federal University of Rio de Janeiro (UFRJ), Ocean Networks Canada (ONC) and Petrobras are developing a test system where carbon dioxide (CO2) and methane (CH4) can be released in controlled amounts to a variety of test instruments at a depth of 2660 meters located over a secure Internet connection with collecting sensor and live video monitoring.
So far, the project has selected several sensors developed by universities, research centers and companies around the world, using different technologies including fiber optic, acoustic and pH. Enabling this in situ real time experimentation is the ONC NEPTUNE cabled observatory. With over 800 kilometers of electro-optic cable to depths of 2660 meters the observatory provides power and Internet connectivity to hundreds of underwater instrumentation making it an ideal laboratory to evaluate technologies in situ. We will describe the design of the experiment at the Cascadia Basin site.
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.
Riserless Light Well Intervention (RLWI) operations have been routinely performed for more than 25 years in the North Sea, with 5 vessels delivering riserless production enhancement operations in several hundred wells, helping the Operators to increase the oil recovery rates from their subsea fields.
The ability to carry out frequent, scheduled interventions as opposed to remedial interventions has proven to be crucial to realize higher recovery rates from subsea wells. Such operations are becoming more common and are moving to deeper water, which brings increased technical challenges. At the same time, the ability to substitute expensive deepwater rigs with smaller Light Well Intervention vessels can have a major impact on project cost and scheduling and represent an even bigger opportunity for cost optimization.
In 2015 a brand new RLWI vessel and intervention package have become available for operations in deep and ultra-deep water, taking the RLWI capabilities and successful experience of the North Sea to the deepwater subsea fields of Gulf of Mexico, Brazil and West Africa. 10 years of experience and track record have been capitalized into the design of a new and enhanced deepwater intervention stack (Stack 4), which is deployed and operated from a state of the art RLWI vessel, the
The new intervention stack, now at its 3rd generation, brings increased efficiency and reliability thanks to smaller umbilical, optimized deployment sequences, easier maintainability, elimination of use of guidelines and simplified control system.
On the vessel side, the
The paper will give a detailed account of the opportunities to improve recovery rates in subsea wells by enabling access with this lighter, more efficient, and ultimately more productive intervention method. It will also describe and elaborate on the significant enhancements brought to the design and capabilities of the vessel and of the intervention stack, and will illustrate how these improvements make RLWI even more attractive, efficient and cost-effective for Riserless intervention operations in deepwater wells. The paper will also cover the significant testing and qualification activities carried out during preparation for actual operations, including results from wet system integration testing and actual operations performed to date.
The subsea oil and gas industry in ultra-deep waters requires very long risers, flexible or rigid, which may clash due to their proximity in some field configurations. Clashing should be avoided whenever possible. However, when no mitigation is effective to avoid clashing in a chosen layout or configuration, it is critical to ensure that no damage will occur in any one of the riser sections.
The key to avoiding damage is to correctly evaluate the clashing energy, which is a function of the relative speed between the risers at the moment when clashing occurs, as well as the clashing stiffness and damping of each riser section. The correct evaluation of the clashing stiffness grows in importance when the possibility exists for impact between risers with a high relative velocity.
In order to evaluate the energy effectively absorbed by the riser sections, it is necessary to perform parametric analyses involving different riser types and diameters, riser configurations (single catenary, lazy wave), field layouts, water depths, and associating global clashing analysis with local analysis of the clashing sections using finite element software.
When high velocity impacts occur, part of the kinetic energy is transferred as strain energy at the contact point. Part of this strain energy occurs at the clashing section which will be deformed (local strain), while the other part is transferred to the surrounding area of the risers as axial and bending strains (global strain). This makes it extremely difficult to correctly evaluate the clashing stiffness of each riser. In order to obtain the local stiffness in the contact section, it is necessary to identify how much of the kinetic energy is locally transmitted by the sections.
The aim of this paper is to present a discussion about alternatives on how to evaluate the clashing energy based on the clashing stiffness of each riser. A methodology for the energy clashing calculation is presented in a way where it is possible to identify and separate the local strain from the global strain in a specific contact section based on the kinetic energy transmitted by each part.
Filho, M. A. Deitos (Universidade Tecnológica Federal do Paraná) | Maranho, O. (Universidade Tecnológica Federal do Paraná) | Gandelman, A. (Universidade Tecnológica Federal do Paraná) | Santana, A. Beltrao (Universidade Tecnológica Federal do Paraná)
Inconel 625 is a nickel-based alloy used in oil and gas equipment due to its outstanding corrosion resistance in seawater, chloride-containing environments, and mainly due to corrosion resistance against the production fluid coming from the reservoirs. However, since Inconel 625 is a high-alloyed material, quite more expensive than low-alloy steels used on most parts of christmas trees and other subsea equipment, their use is desired to be optimized as much as possible. One technique largely employed in the oil and gas industry is the cladding of less noble materials with alloy 625 by Gas tungsten arc welding (GTAW) process. The optimization of the weld dilution of overlays together to the quantity of deposited filler metal is a subjected under study for several researchers around the world, however, not much literature is found about this type of study for Inconel 625 by GTAW hot wire method. This work aims to help academic and oil and gas business community providing information related to alloy 625 overlay welding. Weld beads of Inconel 625 (ERNiCrMo-3) were deposited on AISI 4130 80k by GTAW twin hot wire process, with three shielding gas compositions. The usage of helium on gas mixtures utilized on this work showed two antagonistic behaviors regarding the improvement of the quantity of filler metal used and the weld dilution. The smallest reinforcement was obtained with the highest quantity of helium on shielding gas mixture, while highest amount of helium caused an increase in the weld penetration, and thus in the dilution. Pure argon showed the best dilution results, but bigger reinforcement than helium high amounted shielding gas mixture.
Mixtures containing surfactants and polymers to be used in enhanced oil recovery operations should display special features: most notably low (or ultra-low) oil/water interfacial tensions and moderate viscosity. There is a variety of methods employed to assess formulations performance for enhanced oil recovery. Some of these involved wettability measurements, such as the Amott test, but these are typically time consuming.
This communication reports on the use of low-field nuclear magnetic resonance (NMR) to probe rock wettability in the presence of different formulations. Based on the relaxations time, this technique allows a direct assessment of molecular mobility, which in turn is determined if the liquid is bounded to surfaces or free. Based on this, it is possible to monitor the exchange of oil from the porous of rock by water solution. Therefore, the efficiency of formulations can be determined.
Two rock samples, sandstone and carbonate, were employed to reproduce some reservoir conditions. These were first impregnated with oil samples and then exposed to different aqueous formulations and the fractions of oil and water were directly monitored based on the measurement of the spin-spin relaxation time of the hydrogen atoms.
Typical formulations included mixtures of non-ionic and zwitterionic surfactants and high molar mass polymers. These surfactants display little propensity to ion strength effects and cloud points associated to lower interfacial tension values that could be varied with composition. Effects such as nature of the surfactant chain (double vs. single chain, chain length) and mixture composition with respect to their cloud points were found relevant to affect oil displacement capacity.
These results confirm the validity and advantages of this technique, as well as reveal important information about surfactant mixtures with potential for use in enhanced oil recovery.
There is a growing demand within the oil and gas industry for an integrated subsea power system in order to achieve the highest availability of power supply and power distribution subsea. For that reason, since 2010, a subsea power grid system has been under development by Siemens. The purpose of this system is to provide power to subsea consumers like pumps and compressors in deep and ultra-deep waters for long step-outs.
The subsea power supply and distribution system, including all its components, is designed and qualified to work at a water depth of 3000 meters, and up to more than 200 kilometres step-out distance. It will offer an integrated, reliable and cost-efficient subsea power solution for multiple consumers at seabed.
The development and qualification program is currently in its last stages. Testing of the individual components (subsea transformer, switchgear, variable-speed drive and communication/control system) will be followed by a complete system test. Overall, development and qualification program is expected to be completed in 2016, at which time the system will be ready for a full-scale subsea pilot project.
The power system must have standardized, flexible and configurable interfaces to have an optimal fit with the processing system. The integrity of the power system is governed by a dedicated power control and monitoring system which enables transparent and standardized communication with all the power modules. The Subsea Power Grid solution offers an infrastructure with standardized interfaces both on the topside / onshore power generation and to the subsea consumers – both for the power line and for the power control and communication line. This ensures flexible arrangements with the subsea field’s overall processing system without challenging the integrity of the power distribution.
One typical application for Subsea Power Grid solution would be a subsea standalone variable speed drive. The aim of this paper is to perform an overall analysis on how a subsea standalone variable speed drive can be integrated in a typical subsea pumping system without sacrificing the integrity of subsea variable speed drive sub-assemblies designed as part of subsea power grid solution.
Autonomous systems offer expanding capabilities to provide maritime services in a time where saving costs, creating efficiencies and improved safety are vital. Autonomous vehicles are complex systems and therefore their design and development requires careful and detailed planning. Autonomous Surface Vehicles (ASV) is a rapidly growing company based in the UK with offices in the United States and is a leading manufacturer of Unmanned and Autonomous Marine Systems. Utilising specialist expertise and experience in the design, build and operation of Marine Autonomous Systems, the C-Worker 6 Autonomous Surface Vehicle (ASV) was developed for marine operations support in the Oil & Gas industry.
This paper explores the design and build process from a naval architecture, mechanical, electrical and software engineering point of view, from initial concepts to field operations. The authors also assess the presented method in a meta-design manner. With the initial concept and technology capabilities established, ASV collaborated with Oil and Gas service company Technip to establish industry requirements and define the final configurations accordingly through a dedicated technology qualification process. Technological advancements introduced in this 6 meter long vehicle known as the C-Worker 6, include the integration of multiple offshore payload combinations including USBL, ADCP (current meter), CTD, Multibeam Sonar, Acoustic Telemetry, and Passive Acoustic Sonar (PAM) for marine mammal detection. The robust design incorporating an aluminium, self-righting hull makes the vehicle suitable for harsh ocean environments. C-Worker 6 has a 30 day endurance at an average speed of 4 knots and houses fully redundant power propulsion and communication systems.
As a result of the methodology applied, the product development timeline is presented. The paper also presents data evaluated from real missions. Early qualification of the vehicle has shown its ability to perform in the high sea states of the Gulf of Mexico successfully carrying out subsea positioning in 1300m deep waters with 2.5m waves, as well as having performed Touch Down Point (TDP) monitoring support for S-Lay pipe installation during the technology qualification. The vehicle has since undertaken different mission witch includes a 5 day deployment in the Irish Sea where it held station and extracted data from a subsea platform via an integrated acoustic modem payload, a multibeam survey on a future wind farm installation and Pacific Acoustic Monitoring (PAM) in the Gulf of Mexico.
The interest for using unmanned and autonomous systems to support marine operations in Oil and Gas industry is anticipated to grow with the industry needs and requirements for more efficient, cost effective and safer solutions.
Santos, I. H. F. (Petrobras) | Machado, M. M. (Petrobras) | Russo, E. E. (Petrobras) | Manguinho, D. M. (Petrobras) | Almeida, V. T. (Petrobras) | Wo, R. C. (Petrobras) | Bahia, M. (Petrobras) | Constantino, D. J. S. (Petrobras) | Salomone, D. (EMC - Brazil Research Center) | Pesce, M. L. (EMC - Brazil Research Center) | Souza, C. (EMC - Brazil Research Center) | Oliveira, A. C. (EMC - Brazil Research Center) | Lima, A. (PEE-COPPE / UFRJ.) | Gois, J. (PEE-COPPE / UFRJ.) | Tavares, L. G. (PEE-COPPE / UFRJ.) | Prego, T. (PEE-COPPE / UFRJ.) | Netto, S. (PEE-COPPE / UFRJ.) | Silva, E. (PEE-COPPE / UFRJ.)
Big data analytics, applied in the industry to leverage data collection, processing and analysis, can allow a better understanding of production system's abnormal behavior. This knowledge is essential for the adoption of a proactive maintenance approach instead of conventional time-based strategies, leading to a paradigm shift towards Condition-Based Maintenance (CBM) since decision is now based on the usage of a huge, diverse, and dynamic amounts of data as a means to optimize operational costs. This paper reports an investigation of the emerging aspects in the design and implementation of big data analytics solutions for offshore installations in order to allow predictive maintenance practices.
Condition-based maintenance focuses on performing interventions based on the actual and future states (health) of a system by monitoring the underlying deterioration processes. One of the building blocks of a CBM design and implementation is the prognostic approach/system, which aims to detect, classify and predict critical failures. Considering the massive amounts of data available from a Stationary Production Unity (SPU), the use of techniques that properly deal with such a big data scenario became essential. The use of parallel processing to ingest, transform, and analyze different kinds of data in near real-time basis allows the construction of a valuable tool for implementing CBM.
This paper presents a comparison of different approaches for RUSBoost and Random Forest (RF) classification, in constructing a prognostic system for a specific class of turbogenerator failures from a chosen Petrobras' Floating Production Storage and Offloading (FPSO). Besides the comparison of different classifiers, a contribution of this work lies on the use of data acquired not only from machine sensors (telemetry data) but also non-structured data regarding the most critical failures acquired from official reports, e.g. operator's machine event annotations. Those reported annotations were correlated to telemetry data to identify real critical failures, and simultaneously avoid false positives.
Electrical Submersible Pump (ESP) systems have been applied successfully for seabed hydrocarbon boosting for years. However, the design of ESPs for in-well applications presents several limitations for its use on the seafloor. The long slender body and limited gas handling capabilities have historically been important factors restricting the wider use of ESPs in subsea applications. In order to overcome the main design challenges, ESPs have been placed in caissons that enable gas/liquid separation and installation of the pump in a vertical position. This arrangement has resulted in high installation and work-over costs, limiting the acceptance in subsea applications. For low gas applications, skid based subsea ESP designs have also recently emerged, but these are large and heavy, which also leads to higher installation and work-over costs.
The Subsea Production Alliance between Baker Hughes and Aker Solutions has developed an innovative new solution to these challenges in the form of an ESP system installed in a flow line jumper. This new solution utilizes the same well proven ESP and increases its gas tolerance by utilizing state-of-the art technology used in subsea separation and boosting applications. Fluid conditioning, gas/liquid mixing and liquid recirculation together with field proven control algorithms form the revolutionary flowline booster system. Installation and retrieval of the jumper-mounted ESPs are as simple as retrieving a standard flowline jumper by using a light installation vessel and field proven tie-in technology. This new system provides for a step-change in operational robustness and cost-benefit for subsea boosting solutions.
This paper presents the concept and highlights the benefits of modularity, ease of installation and replacement, operability and client value. A simulation of the operational performance of the system applied in a brown field application is presented. A commercial comparison between the flowline booster system and a skid based ESP boosting system is also presented.