bluuebunny/crossref_metadata_2025 huggingface dataset:
Operational Guidance for Thruster Assisted Mooring
Authors: Ejdfors Kristian , Falkenberg Erik , Okkenhaug Siril , Johannesen Magnus
Published: April 2023

In 2019 DNV initiated the TAM JIP motivated by i) that non-optimal operation of thruster assisted mooring systems is believed to be a contributing factor for the mooring line failures thet the industry has experienced, and ii) that last generation semi-submersible drilling units rely more heavily on their thruster systems. How to safely operate thruster assisted mooring (TAM) systems while also learn how one can do it more cost efficient have been central in the JIP work.

This have been done by analyses of real operations, a parametric study on the performance of a TAM operation and experience shared by the participants. This paper presents recommendations for how to operate a TAM unit. The results are also used to give analysis guidance for TAM presented in a companion paper at OTC 2023 /1/.

Logged data from the participants was used to analyze real operation and interviews of different stakeholders was undertaken. A parametric study was the main part of the analysis work, this was performed in time domain for 3 TAM units of different sizes at 3 water depths and a range of metocean conditions and controller settings. The models were benchmarked both towards real measurements and a state-of-the-art TAM controller to ensure realistic results. Other inputs from the participants were obtained in several workshops.

Based on the results from the parametric study recommendations to DP system settings are given for different scenarios, such as when it is recommended to use damping only mode, and thereby save fuel, when it is recommended to include full position control and when mean thrust is sufficient. In extreme survival sea state, the main objective of the positioning system is to keep the mooring tensions at an acceptable level, and this puts other demands on the control system than in an operational sea state with strict position tolerances.

Through workshops in the JIP the need for proper training of TAM operators was emphasized and recommendations to preparation of controlling documents such as mooring analyses and ASOG (Activity Specific Operation Guideline) was discussed and agreed, and this is also presented in this paper.

Through the insight given by the results from the parametric study and interactions with the participants a better understanding of how TAM operations should be performed has been achieved, ensuring safer and more cost-effective TAM operations.
Optimizing the Inspection Plans of Subsea Equipment Using Risk Analysis Methodologies and Simulations
Authors: Barros Leonardo Oliveira , Orlowski Rene Thiago Capelari , Maturana Marcos Coelho , Schleder Adriana Miralles , Martins Marcelo Ramos
Published: April 2023

Cost reduction and risk management are well-know concerns in the offshore oil and gas industry and many approaches have been explored to deal with these issues. One way to reduce risk and costs associated with oil and gas exploration is performing the optimization of inspection plans, allowing monitoring the integrity of equipment while optimizing the use of inspection techniques, and tests and their respective frequencies based on the risk associated with the operation. This paper presents a methodology developed to perform this optimization and four case studies in which the methodology was applied.
Titanium Pull-In Tube: A Free SCC-CO2 Solution for Pre-Salt Fields
Authors: Magalhaes Ferreira Fabio , Ferreira Mendes Pedro L. , Mansur Barros Claudio R.
Published: April 2023

Since the beginning of Campos Basin production in earlies 70s PETROBRAS has been prioritized flexible lines application in its offshore oil production projects. After the first fail involving flexible pipelines, related to the corrosion mechanism known as CO2 Stress Corrosion Cracking (SCC–CO2)(1), PETROBRAS decided to intensify the use of rigid pipelines in the pre-salt fields with high CO2 partial pressure. This article aims to introduce the Titanium Pull-in Tube (TiPT), a new carbonate-rich acidic immune technology developed and patented by PETROBRAS to enable the rigid riser application in the first pre-salt oil production platforms, which designed initially to receive only flexible risers. The development of TiPT had been performed through a set of analysis encompassing: extreme load, wave fatigue load and pull–in loads. The results show the feasibility of the new interface for rigid risers. In addition to enabling rigid lines application, TiPT will provide savings and a better operational efficiency to the Pre-salt platforms.
SIIBED: Subsea Ice Interaction Barriers to Energy Development – Overview
Authors: Ralph Freeman , King Tony , Fowlow Chad , Butler Chad , Paulin Mike , Price Jason , Ogban Peter
Published: April 2023

The objective of this paper is to provide an overview of the Subsea Ice Interaction Barriers to Energy Development (SIIBED) project including work on acceptance criteria used in finite element analysis (FEA), physical modelling and risk analysis activities.

The overall structure of the SIIBED program and the relationship between the various tasks is presented. SIIBED is a continuation of two previous projects funded by Energy Research & Innovation Newfoundland and Labrador (ERINL): Alternatives to Flowline Trenching (AFT) and Alternatives to Weak Links (AWL). The SIIBED scope was expanded to include subsea cables, reflecting the interest in moving towards electrification of offshore operations. Numerical modelling of iceberg interaction with rigid pipelines, flexible flowlines and cables requires an understanding of elastic/plastic stiffness and stress/deformation limit states. This paper reviews existing technologies, industry standards and best practices.

The behavior of rigid pipes in an ice grounding environment is fairly well understood and was reviewed in relation to applications supporting developments in the Beaufort Sea. In contrast, the construction of flexible flowlines is much more complex and variable, and firm guidelines on design strain limits are lacking for the application considered here. Subsea cables are even less well understood. When considering subsea cables and the adoption of limit state design criteria, the model of failure consequences was examined in the context of approximately a 15 second ice-pipe-soil interaction before the iceberg passes over-top. Under loading, the three conductors in an AC cable must maintain separation to prevent electrical arcing. Insulation around a single conductor DC cable must remain intact. It has been observed that, unlike steel pipes that ovalize when compressed restricting access for pigging as well as loss of strength integrity, the cables (particularly the insulation around conductors), bounce back to the original shape. The potential loss of conductivity could not be tested. If cables bounce back, then to prevent arcing, a cable could be de-energized for the short period ice keel interaction and re-energized after the iceberg passes over-top.

While a considerable understanding for modeling rigid pipelines against iceberg keel interaction exists, analysis of subsea cables is much less understood. These are, however, now necessary as the oil and gas industry transitions to a net zero carbon footprint or alternative energy sources (e.g. offshore wind power) are developed in ice prone regions. While more testing and verification work is needed, this work suggests that requirements for protecting rigid pipelines may not be appropriate for electrification cables, possibly too, flexible flowlines.
What Does Energy Transition Actually Mean for the Oil & Gas Industry?
Authors: Hoxha Besmir Buranaj , Nair Aravind
Published: April 2023

What does energy transition mean? What are we transitioning to? Why now? How long will it take? And how will we get there? The scope of this paper focuses on defining the different drivers and strategies that various entities in the oil and gas industry are utilizing to transform operations and business strategies – specifically segmented to the United States, United Kingdom, and Europe.

To operators, the primary focus is to transform their business (influenced by regulations and legislative policies) by reducing their carbon emissions while also investing in cleaner energy sources, such as geothermal, renewables, and hydrogen. For service companies, aside from internal decarbonization, it is another potential revenue stream by offering products, equipment, and services to operators in the ‘energy transition sector’. For ‘developing’ countries, the primary focus is on the fundamental commitment for energy diversification (e.g., energy security) in order to achieve sustainable self-sufficient energy source/s that are less impacted by socio-economical or geo-political factors. In contrast, for ‘developed’ countries, it is net-zero goals and energy security. For example, agencies such as the Department of Energy, offering funding or incentivizing projects on decarbonization, clean energy initiatives, or supporting emerging technologies on renewable and alternative energy.

In hindsight, the energy transition shift will have different outcomes to different parties. The main focus in this paper is to break down the ‘buzz word’ associated with energy transition as a popular concept, fettered by technology hype, political agendas, and/or financial influences that are inherently attached to the term ‘energy transition.’ Furthermore, the paper will explain the misconceptions and intricacies behind the strategies that companies, and government agencies are undertaking in this energy paradigm shift.

Lastly, emphasis will be made on what is driving this paradigm shift: technology, policy, and cultural change. Further light will be shined on how the industry's previous institutional mindset has changed to a broad, open-minded desire to create a net-positive outcome using Environmental, Social, and Governance techniques.
Analysis Guidance for Thruster Assisted Mooring
Authors: Ejdfors Kristian , Falkenberg Erik , Okkenhaug Siril , Johannesen Magnus
Published: April 2023

DNV initiated the TAM JIP in 2019 motivated by i) that the industry has experienced mooring line failures where non-optimal operation of thruster assisted mooring systems is believed to be a contributing factor, and ii) that last generation semi-submersible drilling units rely more heavily on their thruster systems. Through the TAM JIP, DNV has studied how thruster assisted mooring (TAM) systems should be safely operated, and how to adjust the design requirements accordingly. It is vital that the design analyses reflect how the TAM system will be operated offshore - this has not always been the case in the past.

Central in the work has been analyses of real operations, a parametric study on the performance of a TAM operation and experience shared by the participants. This paper presents analysis guidance for thruster assisted mooring. The results are also used to give recommendations for how to operate a TAM unit, and this is presented in a companion paper at OTC 2023 /1/.

The parametric study was performed in time domain for 3 TAM units of different sizes at 3 water depths and a range of metocean conditions and controller settings. Both a Kalman filter controller and an idealized controller representing assumptions in a frequency domain analysis have been studied. The analysis models used in the parametric study have been benchmarked towards both measurements from real operations and a state-of-the-art TAM controller to ensure realistic results.

The study showed that it is feasible to establish a time domain analysis approach that allows for modelling non-linearities such as thrust limitations and thruster delays. In time domain analyses, the use of rotatable thrusters when the mean load is small may induce excessive azimuthing in thrusters. Such cases should be modelled by fixed direction thrusters. In real operations this is avoided by operating thrusters in bias groups. For frequency domain analyses correction factors for low-frequency motions have been proposed in lower sea states. For high sea states when constant thrust is applied no such correction factors are needed. Furthermore, it is always important to check that max thrust is not exceeded in the analyses.

The validity of frequency domain programs, commonly used in analysis of TAM operations, has previously been found to be inaccurate /2/. Furthermore, it has been a discussion in the industry how, and if these frequency domain analyses can be run ensuring conservative results. Through a systematic study in the JIP guidance for analyses in both time domain and frequency domain are given. Thus, implementation of the findings provided in this paper will give the industry more realistic analysis of TAM operations than what has been common practice.
Next Generation Building Blocks of an Autonomous Subsea Vehicle
Authors: Glenn Casey
Published: April 2023

The development of new resident and autonomous underwater vehicles (AUVs) has been enabled thanks to advances in secure and reliable Ethernet communication networks, software, batteries, and positioning sensors. Applying these technologies through a joint project between Oceaneering, an engineering services company, and multiple oil and gas operators, a new hybrid AUV/ROV system has been developed to optimize the delivery of pipeline inspection services and pave the way for future geophysical survey and resident AUV/ROV applications.

The vehicle comprises modules that connect to a next-generation distributed controls system, which increases flexibility by offering plug and play capabilities.

The hybrid vehicle underwent more than two years of qualifications and testing at the Oceaneering Living Lab in Tau, Norway, and offshore in the North Sea, where components like software, sensors, and batteries were rigorously tested. After years of in-water testing, the vehicle surpassed TRL 6 requirements for pipeline survey and inspection scopes. The unit can work as an ROV or operate in an autonomous and tetherless AUV configuration, with a working range of 120 km, a working depth rating of 6000 msw, top speed of 3 m/s, and sufficient reliability to support subsea deployment up to six months.

The hybrid AUV/ROV has demonstrated the ability to carry out low-altitude inspection and survey on pipelines of different diameters. It can track pipelines at 3 m to 5 m altitude from the seabed, providing high-resolution survey data, and at 8 m altitude for reconnaissance and seabed mapping.

The vehicle control software includes specific behaviors to locate burial, crossing, and free span events and to maximize data acquisition value.

This new hybrid AUV/ROV is outfitted with high-specification instruments, such as an inertial navigation system, laser scanning system, and multibeam sonar technology, that enable it to achieve unprecedented pipeline tracking within a close proximity to the pipe. Additional hardware modifications are planned to expand the breadth of the vehicle's capabilities to include cathodic protection readings, cleaning operations, and light intervention.

This paper explains the building-block development concept and describes the individual modules that make up the new AUV/ROV. It presents the challenges encountered in creating this innovative vehicle and explains how issues were resolved as well as the methodology behind solving them.
Making Deep Sea Mining Cleaner and Greener
Authors: Rizea Steven A. , Halkyard John E. , Wodehouse Jim , Blevins Robert D. , Johnston Lori , Adamson James , Joshi Kamlesh
Published: April 2023

This paper describes concepts to minimize the plume generated by unwanted sediments collected along with manganese nodules during hydraulic mining operations. The concept consists of two novel technologies: separating all sediment from the collected nodule slurry to eliminate sediment from entering the riser and lift system, thereby reducing, or eliminating a midwater plume, and subsea electrocoagulation (EC) to create rapidly settling flocs of sediment being discharged from the seafloor collector. The first approach involves designing a gravity separator (hopper) whereby the larger particles fall through an outlet and are entrained with clean water before entering the riser, while all the sediment and water collected with the nodules exits at the hopper overflow. To prevent sediment from being entrained with the nodules, a "reverse hydrocyclone" and secondary hopper is incorporated in the underflow circuit to help maintain a positive pressure differential between the riser inlet and the hopper during operations. The second approach employs the marinization of proven wastewater treatment EC technology to create large metalliferous flocs which attract the sediment causing rapid settling when the slurry is discharged aft of the collector. Work reported here includes numerical (CFD) confirmation of the separator performance, and experimental demonstration of the EC application, as well as techno-economic assessments of the cost impacts of implementing these technologies. This work was supported by the U.S. Department of Energy, Advanced Research Projects Agency – Energy (ARPA-E), and with contributions of sediment for the EC tests by The Metals Company from the Clarion Clipperton Zone and Ocean Minerals, LLC from the Cook Islands EEZ.
Benchmarking Deepwater Semisubmersible Floating Production Unit Developments Sanction to First Production Cycle Times in a Post Pandemic Era
Authors: D’Souza Richard B , Basu Shiladitya
Published: April 2023

The success of a major deepwater capital project is significantly influenced by how well capital and schedule commitments made at the time of Final Investment Decision (FID) are met. Front End Loading (FEL) activities are the Operators’ work processes leading up to FID. FEL includes reservoir characterization and appraisal, definition of the well construction program and the facilities (production platform, subsea, umbilicals, risers and flowlines (SURF), export systems) that process and export reservoir fluids.

Most deepwater developments can be categorized as major capital or megaprojects, with capital costs ranging from $3 billion to $10 billion. The offshore industry's track record for delivering megaprojects within sanctioned budget and schedule is not stellar. Project economics are seriously eroded if budgeted cost and schedule slip by more than 10%. There are many reasons for slippage, but a root cause is the inadequate allocation of contingency and availability of accurate, current benchmarking data. Operators require independent cost and schedule benchmarking of risked capital costs and Sanction to First Production (STFP) schedules, established at the end of FEL, to validate contingencies before green lighting a project.

Schedule benchmarking compares risked STFP schedule at FID to actual STFP of an analogous project in production. The fabrication, integration, transport, installation, hook up and commissioning of the Floating Production Unit (FPU) is typically on the critical path to first production. Since the FPU topside operating weight is a key schedule driver, schedule benchmarking is comparing the planned STFP of the project awaiting sanctioned to the actual STFP of a producing analogoue FPU project with a topside of similar operating weight and complexity.
Direct Electrical Heating: Single Pipe Vs Pipe-In-Pipe: Is a Double Wall Worth It?
Authors: D’ Huart Pierre Emmanuel , Jardin Antoine
Published: April 2023

The High-Performance DEH-PiP is a new technology for electrical heating of subsea tie-back flowlines, that minimizes disturbances to the construction and installation process wrt. to standard PiP avoiding the use of internal heating cable, while reaching the same electrical efficiency as e.g. Electrical Heat-Traced (EHT) pipe-in-pipes.

It thus boasts a much higher efficiency than a Wet Insulated DEH pipe. However, no comparison has been done so far on the CAPEX needed. Is a DEH PiP worth its value? Is the second pipe wall worth the expense? The aim of this paper is thus to present a novel comparative study between DEH-PiP and a traditional Wet Insulated DEH single pipe

A complete engineering study has been made (flow assurance, pipeline design, electrical engineering, installation engineering) based on real cases. Full EPCI costs have been evaluated, local content for fabrication quantified, and associated carbon emissions as well during operations

The study concludes that High Performance DEH Pipe-in-Pipe is difficult to compare to Wet insulated Single pipe

The technology was 3% more expensive in CAPEX on the 30km tieback studied, but the margin remains small, and other factors may influence the conclusion. The two technologies remain comparable in a 20-40km range. A DEH-PiP offers more thermal and power efficiency, and other benefits such as greenhouse gases emissions savings. Operational downtime and production fluid properties should also be considered in decision making.
Enhanced ROV Performance Using AR/VR HUDs
Authors: Sapp Casey
Published: April 2023

Custom Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR) Human Machine Interfaces (HMIs) or Heads Up Displays (HUDs) are proving to offer major benefits for Remotely Operated Vehicle (ROV) operators in enhancing situational awareness, decreasing task time, and at a corporate level reducing the total cost of an ROV operation. In this paper Casey Sapp will examine the state of the technology, pertinent case studies, and operator outcomes from recent tests.

The AR/VR interfaces described in this paper leverages the recent development in affordable Commercial-Off-the-Shelf (COTS) Head Mounted Display (HMD) technology to visualize operational ROV data with real end users and commercial clients. Technology demonstrations and user data acquisition has occurred since 2018 starting with Monterey Bay Aquarium Research Institute (MBARI) and currently with Navy Explosive Ordnance Disposal (EOD) PMS 408.

The findings in this paper offer scalable system architectures and tools which are possible to implement today by ROV services companies Oil & Gas industry. The conclusions show that AR/VR HUDs have a material impact on operator satisfaction, decreasing complexity of a project, and Return on Investment (ROI) by reducing the total cost of an operation. Blue Ring has ongoing studies which are consistent with studies performed in the past with partners including Monterey Bay Aquarium Research Institute (MBARI) and are establishing improved performance and cost reductions. More statistical results are forthcoming.

Through five years of prototyping and experimentation with end users both in live environments and through simulation Casey will provide real case studies and observations where AR/VR HUDs have made a difference with real organizations who use ROVs. The concepts and results can be easily transferred to other subsea industries including Oil & Gas.
3D Mad Dog Pressure and Stress Prediction Coupling Seismic Velocities, Pressure, and Stress Measurements
Authors: Nikolinakou Maria A , Dosser Xiaonan Wang , Flemings Peter B , Johri Madhur
Published: April 2023

We predict pressure and stress in the 3D Mad Dog field using the Full Effective Stress (FES) pressure-prediction workflow. The FES workflow incorporates the full stress tensor (e.g., lateral stress and deviatoric stresses) into pressure prediction: it uses a geomechanical model to predict mean total and shear stresses in the 3D field and a relationship between velocity and equivalent effective stress (instead of vertical effective stress) to account for both mean- and shear-induced pore pressure generation. In complex geologic settings, such as salt basins or thrust belts, compaction depends on non-vertical and differential stresses; in such settings, the FES method offers a significant improvement over the traditional approach, that is based on the vertical effective stress. We focus our study on the anticline below the Mad Dog salt at the original platform area. We quantify the mean and shear-induced overpressures and show that shear-induced pressures account for 80% of the total overpressure in front of the salt. We also show that shear-induced pressures are the source of more than 1.5ppg overpressure in the anticline below salt, where the mean-stress approach alone predicts underpressures (less than hydrostatic). Higher pressures and the decrease in lateral stress in the anticline area lead to a 1ppg drilling window (defined in this paper as the difference between the pore pressure and minimum principal stress at any given depth). This drilling window is shifted to higher overpressures by 0.4ppg compared to the VES prediction. We find that the stress ratio in the mudrocks decreases to ~55% of its uniaxial value. Furthermore, we show that the velocity-informed geomechanical model is able to predict the pore pressure regression observed at Mad Dog and the regional hydraulic connectivity in the area. The three-dimansional (3D) geomechanical model is built in Horizon (Elfen). The known pressure regression in the sands is modeled; mudrock pore pressures are initialized using the VES estimate. Modified Cam Clay is used to quantify mean- and shear-induced compaction. Overall, we demonstrate that incorporating the full stress tensor is important for pressure and stress prediction at Mad Dog, and that the FES method, by providing both pressure and stress, can help improve drilling-window estimates.
Transforming the Trajectory Control from Conventional Motor Drilling to Autonomous Rotary Steerable Systems
Authors: Phan Van Chinh , Al Fakih Abdulqawi , Gonzales Luis Felipe , Osman Ahmed
Published: April 2023

The most challenging section in drilling directional wells is the curve section. This curve section used to be drilled by a conventional steerable motor with a slide/rotate decision with the greater challenges of poor hole cleaning efficiency and increased drilling time. The Rotary Steerable System (RSS) was introduced in a turnkey project by eliminating slide and rotate limitations to reduce the cost per foot. Initially, the downhole automation of the RSS was limited to holding verticals and inclinations. Later, the closed-loop control progressed to hold inclination and azimuth, but the curve section remained unautomated. The driller continued to drill the curve section manually by adjusting the steering parameters. A new Autonomous Downhole Control System (ADCS) recently integrated into the RSS enables autonomous drilling of the curve section, further reducing human inconsistencies and improving borehole quality, drilling efficiency, well economic, and reducing carbon footprint.

Multiple offset wells were analyzed. Different BHA configurations were studied with various stabilizations to increase the dogleg capability. Bit records were gathered and analyzed for steerability and stability. The trajectory design was revisited to ensure minimum dogleg severity was considered at the planning stage. This ensured staying within the RSS's technical limits and avoiding unplanned pulling out of the hole due to failure to maintain the trajectory. The specific field strategy was prepared with the digital journey of intelligent planning, intelligent execution, surface automation, and downhole automation. The RSS was incorporated with the newly developed ADCS, placing the driller into the supervisory role to monitor the digital drilling system.

The RSS was introduced in a turnkey project to reduce the cost per foot by improving the ROP, drilling shoe-to-shoe in one run, having efficient hole cleaning to avoid stuck pipe incidents, and having a smoother borehole for running casing and liner. The new ADCS incorporated into the RSS completed the automation puzzle and has been tested successfully in many wells on the same project. It transfers human decision-making to the downhole control, further increasing ROP in some cases by up to 100% and up to three days saved on each well drilled.

This paper will illustrate the detailed BHA change in curved and horizontal sections from mud motor to the RSS with the significant progression of downhole automation and a future view for autonomous drilling in similar fields worldwide.
Acoustic Set Liner Hanger for HPHT Applications
Authors: Nordenstam Leif , Krueger Matt , O’Connor Keven Michael , O’Keefe Kyle
Published: April 2023

Thousands of liner systems are deployed annually to reduce cost, time, and risk compared to casing long strings. Early liner hanger systems would require mechanical actuation (rotating or reciprocating drill pipe) to deploy the liner section. This method limited the ability to rotate and reciprocate the liner string when encountering high deviation and restrictions, particularly as well trajectories moved towards higher levels of deviation. The hydraulic actuated systems, found in both conventional and expandable liner hanger systems, allow the liner string to be manipulated with rotation and reciprocation. The traditional method for setting a hydraulic liner hanger includes the use of single or multiple activation balls being dropped from the surface so that pressure can be applied to the work string to function the hydraulic liner hanger and running tool. However, in complex wells such as HPHT, deep-water, and extended-reach applications, many operational issues experienced with running hydraulic liner hangers are related to limited surface indications on what is transpiring downhole and not landing the ball on seat, which can lead to Non Productive Time (NPT).

Developing a liner hanger system that provides real time downhole readings throughout the drill pipe string and does not rely on pipe manipulation or dropping activation balls from surface will dramatically decrease high impact NPT and increase the overall operational capabilities of liner hangers. To respond to these industry needs, a new system to deploy and actuate a liner hanger on demand was needed. This paper presents a novel system which utilizes distributed sensing along the work string by means of an acoustic telemetry network. The liner hanger system uses that same acoustic network to communicate to and actuate the liner hanger, removing many of the challenges facing liner installations.
Results of the Initiatives Conducted by New FPSOs Program (PROFORT) in the First Period of Execution
Authors: Froes da Silva Lourenço Lustosa , Henriques Carlos Cunha Dias , De Lima Leonardo Schacherl
Published: April 2023

The purpose of this paper is to demonstrate the results achieved in the first three years of FPSO projects execution after a Program called PROFORT (New FPSOs Program) in Company, which combines relevant contract, engineering and market pillars to achieve Company goals on New FPSOs Program. This paper describes Company surface installation department main initiatives in the PROFORT program. Those initiatives were first identified in 2019 as main pillars of Company Strategic Plan to build FPSOs. The first part of the Program was concluded with the successful signature of the contracts for the P-78 and P-79 FPSOs construction. Some of the initiatives of PROFORT program are related to: (i) contract terms and exhibits; (ii) basic engineering; (iii) bidding process; (iv) basic engineering endorsement and (v) contractual tools.

Company has been collecting lessons learned from projects executed over the last 10 years. Based on a prioritized list of lessons learned, PROFORT program defined its action plan, with following key points: 1. The contract was updated to have a single main contractor with a construction (and design) track record consistent with the upcoming complexity of new FPSOs generation (Oil processing capacity: 180 kbpd; Liquid processing: 200 kpd; Water injection: 240 kbpd @220 bar; Gas Compression - 7,2 SMMm³/d; Export – 3 SMMm³/d; Water Depth: ~2.000 m; Spread Mooring; high CO2; contaminants etc.). 2. The FPSO basic engineering evolved to integrate the contract and together with an initial period of validation by contractor (through a basic engineering endorsement). The intention is to bring to the initial phase of the contract the major discussions and therefore to minimize scope changes and consequent impacts on late execution phase. 3. The contractual tools, as a pre-defined small amount of unit prices, were included so that the management of the contract can solve minor scope changes promptly and stop a "snowball" effect.

The combined initiatives are the PROFORT program. This program fosters stronger integration and coordination in Petrobras surface installation project teams by sharing lessons learned and existing knowledge. From an external perspective, this way of working has allowed a better alignment of interests between Company and its suppliers with focus on Strategic Plan target of delivering the new FPSOs.
Magnetic Anti-Scaling Accessory for Offshore Wells
Authors: De Souza Júnior José Roberto , Deroubaix Antoine , Nogueira Raynel Lopes , Machado Gabriel , Silva Jorge Alberto , Pusard Mickael , Doria Andre Santos , De Oliveira Paulo Guilherme Oliveira , De Oliveira Fernando Salatiel , Ferreira Marcus Vinicius Duarte , Oliveira Antonio Francklin , Martins André Leibsohn
Published: April 2023

Scale build up is a challenge faced by the O&G Industry. During production, it may cause clogging of pipes and lead to well interventions. An alternative solution increasingly studied over the years is the magnetic treatment of the fluids. This study describes the development of magnetic anti-scale accessories for deployment in offshore wells to figth scaling. Two accessories have been designed and manufactured according to the criterias defined by O&G operator. Qualification tests (vibration, shock, and hydrostatic tests) and magnetic measurements have been conducted to assess the accessories robustness and both were approved for field test. One accessory has already been successfully installed in an offshore field of Brazil and a comprehensive installation program of more accessories for the next years is being designed within PETROBRAS to better evaluate the technology efficiency.
Advanced Digital Solutions for Remote Operations and Minimally Staffed Facilities
Authors: Godavarthi Rama , Leto Alessandro
Published: April 2023

Digital transformation enables companies that adopt digital tools to improve efficiency and advance innovation. For offshore oil and gas operators benefits of digital technologies include: minimization of risks mobilizing personnel offshore; data-driven methodologies that can identify opportunities to reduce OPEX while maintaining quality; and reduced downtime of critical equipment with optimized maintenance, avoiding any compromise on cybersecurity standards.

We explore an unmanned rotating equipment package solution, developed in collaboration with primary offshore operators. Unmanned operations of equipment are achievable with the introduction of different solutions: hardware and control system modifications, surveillance systems, and digital services for advanced degradation monitoring. In maintenance optimization, the models are used to build degradation patterns and estimate residual useful life, thus enabling risk-based maintenance. Risk level is also illustrated with the FMEA methodology, which capitalizes on the fleet-based expertise.

Maintenance activities requiring people at site are carried out during campaign visits, typically scheduled every 6 months. As opposed to a reactive-based approach, the residual life models and risk-based approach of maintenance optimizer helps prioritize work scope during these visits.

Beyond benefits due to on-site tasks reduction or executed remotely, unmanned technology offers advantages such as increased safety, a lower carbon footprint and reduced total cost of ownership.
Flow Characteristics of Intermittent Flow in Inclined Pipes
Authors: Zhu Qianwei , Fan Yilin , Pereyra Eduardo , Sarica Cem
Published: April 2023

The importance of churn and pseudo-slug flow has been recognized, especially during recent years. Churn and pseudo-slug flow characteristics study in inclined pipes are still quite limited. An experimental study was conducted to investigate the inclination angle effect on slug to churn/pseudo-slug transition and the slug (Taylor Bubble) flow existence in large diameter pipes. The tests were conducted in a 0.1016-m ID pipe facility for inclination angles ranging from 2 to 90 degrees at 84-psia test section pressure. Tap water and compressed air were used as the test fluids. Wire-Mesh-Sensors (WMS) were used for flow characteristics measurement and visualizations.
Integrated Asset Lifecycle Management for Rotating and Static Equipment Using Machine Learning: A Review
Authors: Kusumawardhani Mayang , Markeset Tore
Published: April 2023

The accelerated pace of digital advancement has propelled organizations’ adaptation of sensor technologies in the operations and maintenance of the production facilities to stay relevant. Together with it, the industry is also encountering post-pandemic challenges in logistics, costs and the commitment towards the net zero environmental targets in 2050. Further, without a sound understanding of machine learning and statistical techniques, an organization might fail to harness the optimum value of sensor data. Thus, this paper provides an overview of various techniques used in operations and maintenance of rotating and static equipment. The paper aims to find an integrated model that can anticipate equipment failure and optimize the spare parts replacement time, ultimately optimizing decision-making in managing the asset's lifecycle.
A New Mooring System for Floating Offshore Wind Turbines: Theory, Design and Industrialization
Authors: Wu Yongyan , Leitch Peter , Pedersen Skule , Nærum Even
Published: April 2023

There are technical and commercial challenges in the mooring of floating offshore wind turbines (FOWTs). Currently, the industry is developing some innovative mooring designs and new mooring components to reduce mooring costs, increase installation and hook-up effectiveness and ultimately reduce the environmental impact.

We propose a new mooring design, the V-Share mooring system, with two lines connecting from two different floater columns to one anchor. Each mooring cluster is "V-shaped," looking down from the sea surface. An anchor attached to multiple mooring lines has been field proven with mooring lines from different floaters sharing anchors. Therefore, all mooring components and installation technologies are field-proven. Numerical simulations verify the effectiveness of the V-Share mooring. Different engineering aspects are discussed, including mooring installation and floater hook-up.

We started with the theoretical analysis for a spread mooring system stiffness in the surge, sway, and yaw directions to demonstrate that the restoring stiffness from the V-Share mooring, as a new system, is comparable to the traditional mooring. Numerical tools further verify this through the restoring stiffness numerical calculations. The comparisons show that the V-Share mooring provides similar horizontal and vertical restoring stiffness and higher yaw stiffness than the traditional moorings. In the case studies, we used one polyester rope semi-taut mooring system and one wire rope catenary mooring system on three-column semi-submersibles with large wind turbines to conduct fully-coupled simulations. The results confirm the similar tension, offsets, and more stable platform motions in the yaw and heel angles. In addition, the V-Share mooring system allows the possibility of hooking up two lines simultaneously. For each FOWT, the V-Share mooring pattern reduces the mooring system footprint and anchor number and achieves savings in CAPEX, geotechnical surveys, transportation, and installation. Moreover, the V-Share mooring is naturally feasible for shared anchors between different floaters in a wind farm, further reducing project costs.

The FOWTs are moving into deeper waters with larger turbines. Multiple mooring lines and large mooring sizes present significant technical and commercial challenges. The V-Share mooring pattern reduces floater motions, mooring footprint, and the number of anchors. It allows for simplified installation procedures and has the potential to improve wind power generation efficiency. The V-Share mooring system can be combined with innovative mooring components or materials to reduce costs further and is also applicable for floaters in other industries such as floating solar or fish farming.
How an Autonomous Offshore Power System Can Transform the Ocean Economy - A Hypothetical Case Study Utilizing an Autonomous Offshore Power System in Northern Lights Carbon Capture and Storage Project
Authors: Slorach Paul , Lesemann Reenst , Leung Pak
Published: April 2023

An Autonomous Offshore Power System (AOPS) provides in-situ power, energy storage, real-time data and communications support, asset management, and other capabilities at sea. It has applications for all offshore industries: energy, defense and security, aquaculture, science and research, and communications. This paper highlights how an AOPS can reduce cost, complexity, and carbon-intensity for existing offshore operations and enable new capabilities for offshore industry leaders.

This new AOPS technology has two primary advantages. First, it unlocks the autonomous, electric future of the ocean economy via ‘local’ power generation and energy storage, in addition to real-time connection to the data cloud. Second, it helps enable a material change in the global energy mix through cost-effective, reliable generation and storage technology for use cases including mobile/static data-gathering and reporting systems, operating equipment, and charging networks for uncrewed surface vessels. AOPS technology will help transform the ocean economy, and thus has implications for offshore industry leaders as they push to reduce costs today and make an autonomous and decarbonized future possible.

A SeaRAY AOPS, which is the focus of this paper, consists of three primary components: C-Power’s SeaRAY surface wave power systemA non-complex, combined mooring, data communications, and power systemVerlume’s Halo seafloor energy storage and intelligent energy management system

The following paper highlights both a real-world and hypothetical deployment of a SeaRAY AOPS, demonstrating its ability to benefit a diverse array of activity in the ocean economy. First, the paper details the work of C-Power and Verlume, in partnership with the U.S. Navy, U.S. Department of Energy, Saab, R2Sonic, Hibbard Inshore, and other industry leaders, to deploy an AOPS at the Wave Energy Test Site in Hawaii for six months, beginning in the first half of 2023. The Hawaii AOPS will power multiple mobile and static assets capable of delivering persistent, self-contained, and self-powered intelligence, surveillance, and reconnaissance (ISR) and reporting capabilities for 24x7x52 maritime defense and border security. The ability to support this use case demonstrates AOPS applicability across a wide variety of offshore applications. Second, the paper explores a theoretical use case to deploy AOPS technology to reduce capital and operational costs and carbon emissions, as well as reduce operational complexity, at the Northern Lights carbon sequestration facility located off the Norwegian coast. While the case study examines the Northern Lights greenfield opportunity using an AOPS in lieu of a power and data umbilical, brownfield upgrades or replacements of failed/failing umbilicals are equally applicable scenarios.
Development of C1q Affinity Chromatography for the Study of C1q–IgG Interactions
Authors: Marshall Michael J E , Knaupp Alexander , Spick Christian , Koese Ilker , Maier Maria , Cragg Mark S , Cymer Florian , Schlothauer Tilman
Published: April 2023

The classical complement system represents a central effector mechanism of Abs initiated by the binding of C1q to target bound IgG. Human C1q contains six heterotrimeric globular head groups that mediate IgG interaction, resulting in an avidity-driven binding event involving multiple IgG molecules binding a single C1q. Accordingly, surface bound IgG molecules are thought to assemble into noncovalent hexameric rings for optimal binding to the six-headed C1q. To study the C1q–Fc interaction of various Abs and screen for altered C1q binding mutants, we developed, to our knowledge, a novel HPLC-based method. Employing a single-chain form of C1q representing one C1q head group, our HPLC methodology was able to detect the interaction between the single-chain monomeric form of C1q and various ligands. We show that, despite a narrow window of specific binding owing to the low affinity of the monomeric C1q–IgG interaction, this approach clearly distinguished between IgG subclasses with established C1q binding properties. IgG3 displayed the strongest binding, followed by IgG1, with IgG2 and IgG4 showing the weakest binding. Fc mutants known to have increased C1q binding through oligomerization or enhanced C1q interaction showed greatly increased column retention, and IgG glycovariants displayed a consistent trend of increasing retention upon increasing galactosylation and sialylation. Furthermore, the column retention of IgG isotypes and glycovariants matches both the cell surface recruitment of C1q and complement-mediated cytotoxicity induced by each variant on an anti-CD20 Ab backbone. This methodology therefore provides a valuable tool for testing IgG Ab (glyco)variants for C1q binding, with clear relevance for therapeutic Ab development.
Modeling and Robust Control for Full-flight Envelope Trajectory Tracking of a QuadCP-VTOL Unmanned Aerial Vehicle
Authors:   Federal University of Minas Gerais, Campos Jonatan , Cardoso Daniel , Raffo Guilherme
Published: April 2023

A robust adaptive mixing controller (RAMC) is designed to solve the trajectory tracking problem of a quad-tiltrotor convertible plane (CP) unmanned aerial vehicle (UAV). This kind of system is a hybrid aerial vehicle that combines advantages of rotary and fixed-wing aircraft. In this work, the equations of motion of this UAV are obtained using the Euler-Lagrange formalism and assuming it as a multibody mechanical system. The non-conservative forces and torques generated by the propellers, servomotors and aerodynamic surfaces, are mapped to the generalized forces vector. Aiming to design the RAMC, an LPV representation of the system is derived from the nonlinear model, from which several mixed H2/H∞ candidate controllers are designed according to the UAV forward motion, and an adaptive mixing scheme is employed to smoothly interpolate these controllers, providing stability to the closed-loop system for the full-flight envelope of the UAV. The efficiency of the RAMC is verified in a high-fidelity simulator developed on the Gazebo and ROS platforms, in which the UAV is required to track a reference trajectory with different flight requirements, such as hovering, transition, cruise and level turn.