bluuebunny/crossref_metadata_2025 huggingface dataset:
Extra and intracellular laccase titers of xylophagic bacteria isolated from adult termite
Authors: Maia Luciana Furlaneto , Hoyos Sérgio Luis Mendes , Watanabe Alex Kiyomassa , Moralez Alane Tatiana Pereira , Furlaneto Marcia Cristina , Daniel Juliana Feijó de Souza
Published: August 2021

Laccase is an important enzyme in terms of its versatile applicability, but its commercial use is limited by factors such as high production cost, low activity and/or stability under given conditions. The objective of this study was to screen xylophagic bacteria isolated from termites for the production of extracellular and intracellular laccases. Six laccase-positive strains were isolated, namely CA, A3, A5, A6, A7 and A8. They were molecularly identified by sequence analysis of 16S rRNA and classified under the genera Bacillus (A7, A8, CA) and Pseudomonas (A3, A5, A6). Laccase was produced by these bacterial isolates by submerged fermentation and was optimized at 37°C, pH 5.5, 6.2 and 7.0, with agitation and 0.5 mM guaiacol (as carbon source). Laccase activity was determined by measuring the oxidation of guaiacol and ABTS (2,21-azino bis[3-ethylbenzthiazoline-6-sulfonate]). Strain A5 produced extracellular laccase titers ranging from 123 to 168 U ml-1. Guaiacol was identified as a better substrate for the quantification of laccase. In conclusion, bacteria harboring the gut of termites can produce extracellular laccase with activity at medium to moderate acidity.
Precast Dapped End - Nonlinear Analysis
Authors: Juříček Lukáš , Zich Miloš , Hasa Michal , Komárková Petra , Bobek Lukáš
Published: August 2021

The article follows the results from the experiments published at the conferences Concrete days 2014 [1] and 2016 [2], in the paper [3], and also in the magazine Beton TKS [4]. The goal of the experiment was the verification of dapped ends with the different configuration of the hanger stirrups. Subsequently, the nonlinear analyses were performed in the scientific program ATENA. In this article, a new comparison with calculations using the CSFM (Compatible Stress Field Method), implemented in software IDEA StatiCa Detail, is performed
Effect of Membrane Forces on Punching Shear Capacity of Flat Slabs
Authors: Vidaković Aleksandar , Majtánová Lucia , Halvonik Jaroslav
Published: August 2021

The paper presents the analysis of the membrane forces and moment redistribution effect on punching shear capacity of flat slabs on the area of the inner column. The previous experimental tests performed on the isolated slab specimens representing the slab-column connections are assessed by the method that uses the levels-of-approximation (LoA) approach, introduced in the fib Model Code 2010. LoA I to III are intended for design and the highest LoA IV, which uses non-linear finite element analysis (NLFEA) combined with the Critical Shear Crack Theory (CSCT) model is used for assessment and a better understanding of the punching shear phenomenon. Both, multi-layered (2D) shell and three-dimensional (3D) continuum elements were used to model the slab-column connection specimen and were found to accurately predict the structural response. The numerical model was then used to conduct a parametric study on the influence of slab continuity on punching shear resistance. The results from a non-linear analysis of continuous slab models are then compared with the punching shear resistance obtained from the code provisions. The paper will present the obtained results by the LoA method and recommendations concerning of NLFEA modelling of RC flat slabs.
Experimental Verification of Slender Reinforced Concrete Columns Design
Authors: Dobrý Jakub , Benko Vladimír , Kováčik Miroslav , Wolfger Hannes
Published: August 2021

The columns have been part of the constructions since the beginning of the buildings and have retained their design and construction importance to the present. The advantage of using more slender elements are less material consumption and more usable space in the interiors. The continuous improvement of the building materials and the use of hybrid structural elements leads to the downsizing of the structural elements. The aim of this article is the nonlinear analysis of the slender rein-forced concrete columns and the loss of stability verified by the experimental tests. Nonlinear calculations can be considered as the most accurate calculation option for the load bearing structural elements. On the other hand, the effect of the “black box” has been, and will be the cause of a large number of building defects. In the Eurocode 2 in chapter 5.8.6 of the European Concrete Design Standard, there is a possibility of using the general nonlinear method in practice, even for the com-pressed elements. In the design of the slender structures, the influence of second-order theory is a very important part of the design. In this publication are described theoretical and experimental analyses of the slender columns, that failed due to loss of stability inside of their design interaction diagram - much sooner than the critical cross-sections reached its resistance. As a part of the experimental preparations, reinforced concrete columns were designed, based on numerous numerical analyses. Later, the chosen columns were tested in the laboratories of TU Wien in Vienna. Experimental verification is one of the main parts of my dissertation thesis.
Production of the Test Timber-UHPC Composite Bridge
Authors: Holy Milan , Čítek David , Tej Petr , Vrablik Lukáš
Published: August 2021

This article presents the results of the experimental development of a unique bridge system consisting of timber beams connected with bridge deck segments made of Ultra-High Performance Concrete (UHPC). The article deals with the production of a full-scale prototype of the timber-concrete composite structure and with an execution of a subsequent load test. The test structure was 3.30 m wide and 10.24 m long and was designed as two beams made of glue laminated timber connected with subtle bridge deck segments with a thickness only 60 mm and with a typical length of 1.50 m. The aim of the production of the test structure was to check some production details and procedures and subsequently to verify the behavior of the composite structure under load by the load test. The load test was performed with a theoretical span of 9.50 m as a four-point bending test to failure. After the overall load test was done, some bridge deck segments were cut from the structure and a load test of the bridge deck in transversal direction were executed to verify the behavior and the load-bearing capacity of the bridge deck segments made of UHPC.
Verification of Composite Steel and Concrete Bed Behaviour for Machine Tools
Authors: Kostiha Vojtěch , Girgle Frantisek , Švaříčková Ivana , Daněk Petr , Stepanek Petr
Published: August 2021

This paper focuses on the theoretical and experimental verification of a behaviour composite reinforced concrete bed for installation in high-precision machine tools. The design solution consists of coupling the steel shell and HPC concrete filling, which ensures the high rigidity of the bed. Studies in this article were aimed at describing, in detail, the behaviour of the bed, from production to setting into its final position. An integral part of the solution was implementing the measurement of the response of the real bed segment using the installed monitoring system as well as the numerical simulations performed on the assembled FEM model. Thanks to the modular design of the bed, it was possible to verify the behaviour of the simulated load during the operation of the machine tool on a smaller sample. The aim is to verify the functionality of the coupling and, based on the comparison of measured and theoretical data, to define the critical points of the composite and, thus, provide a basis for design optimisation in order to maximise the monitored parameters.
Pilot Fracture Tests of Special Fine-Grained Composites
Authors: Rozsypalová Iva , Bystrianska Emília , Koutný Ondřej , Daněk Petr , Frantík Petr , Keršner Zbyněk
Published: August 2021

Mechanical fracture parameters were obtained for special fine-grained cement-based composites from three-point bending tests. A total of four sets of composite specimens were tested. All of the sets of composites were based on a general recipe and differ in the amount of high-strength aggregate and/or dispersed steel fibres present. Standardized prism specimens with a nominal size of 40 × 40 × 160 mm were used for the fracture tests after 131 days of curing. An initial notch was cut in the centre of the prisms with a depth approximately equal to one third of the specimen’s height. Three specimens from each set of composites were tested in the three-point bending fracture test configuration. Load versus midspan deflection diagrams were recorded. Experimentally obtained load vs displacement diagrams were corrected and analysed using the Effective Crack Model, the Work-of-Fracture method and an independent identification technique using numerical modelling. The most important mechanical fracture parameters, such as static modulus of elasticity, effective fracture toughness, specific fracture energy and effective tensile strength, were determined. Compressive and splitting tensile strength values were obtained from the halves of the specimens left over after the bending tests.
Comparison of Methods for Crack Development State for Steel Fibre Reinforced Concrete
Authors: Musil Luboš , Tipka Martin , Hanzlová Hana , Vodicka Jan
Published: August 2021

Fibre reinforced concrete is a composite material that is increasingly used in construction practice. An often-discussed problem regarding the fibre reinforced concrete is the crack development state and post-cracking behaviour. The paper compares the calculations done according to the Eurocode design and calculations done according to the older procedure given by ČSN standard. The calculations are also compared with the calculations done using the SCIA Engineer software. From the obtained results, the complexity of the calculation, the amount of coefficients, and the variance of value given the current standards is evident.
Identification of AAAS Composites Mechanical Fracture Parameters
Authors: Lipowczan Martin , Lehký David , Rozsypalová Iva , Daněk Petr , Rovnaníková Pavla , Keršner Zbyněk
Published: August 2021

The paper deals with selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors in terms of characterization by mechanical fracture parameters. Two composites made of brick dust as a precursor and an alkaline activator with a silicate modulus Ms = 1.0 were investigated. The composites differed in the fineness of grinding of the precursor – in the first set it was 0 to 1 mm, in the second set 0 to 0.3 mm. The filler was crushed brick. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were provided with notches in the middle of the span up to 1/3 of the depth of the specimens after 28 days of hardening. Five to six specimens from each composite set were tested. The specimens were subjected to three-point bending tests, in which force vs. displacement (deflection in the middle of the span) diagrams (F–d diagrams) and force vs. crack mouth opening displacement (F–CMOD) diagrams were recorded. After correction of these diagrams, the values of static modulus of elasticity, effective fracture toughness, effective toughness and specific fracture energy were determined using the Effective Crack Model and the Work-of-Fracture method. After the fracture experiments, the values of informative compressive strength were determined on one of the fractured parts. At the same time, the values of static modulus of elasticity, tensile strength and specific fracture energy were identified using artificial neural networks and F–d diagrams measured and simulated in the ATENA FEM software. All evaluations included the determination of basic statistics of parameters.
Methodology of Controlled Crack Introduction in Cementitious Materials
Authors: Schreiberova Hana , Fladr Josef , Chylík Roman , Trtík Tomáš , Kohoutková Alena
Published: August 2021

Crack formation is a common and generally inevitable phenomenon in the field of concrete structures. On the other hand, the ever-increasing demand for sustainable construction, thus the structures durability, has led researchers to propose and investigate various crack-sealing methods. This study deals with the key aspect of these investigations – the in-vitro creation of cracks. A large number of the conducted studies have been carried out on artificially cracked specimens, and various methodologies of the controlled crack introduction were presented; however, no specific method was clearly preferred. In this paper, several approaches to the crack introduction are applied: cracking through compressive loading, tensile loading, and 3-point bending. Further, different types of specimens are presented: plain concrete, reinforced with short and long steel fibers, and reinforced with steel rod. The achievable crack characteristics, such as widths or its stability over time, are evaluated and compared. This study thus provides valuable overlook of the possible approaches to the controlled crack creation and points out their potential and limitations. Based on the comparisons presented in this paper, the long steel fiber reinforced concrete specimens subjected to 3-point bending are identified as the most appropriate method of crack induction.
Using Nano-Materials to Change Metal Surface Characteristics and Slow the Buildup of Paraffins, Asphaltenes and Other Oil-Based Contaminants
Authors: Patil Ajeeta , Mathias Todd A , Drees Sharon
Published: August 2021

Paraffin buildup is a fact of life in many oil and gas production fields. When downhole reservoirs lose pressure or temperature, paraffin precipitates and builds up on everything from pipe to valves to instrumentation to the walls in vessels. This buildup slows the process, constricts lines, and clogs instruments. Chemical treatments to keep paraffin from precipitating out of the fluid are widely known, but expensive. In addition to treating the liquid, producers should also consider treating the devices in the flow line to resist buildup.

This paper will show how using nano-material to treat surfaces of components in the flow line—such as sensitive instruments, vessels, meters, valves—can slow or stop the buildup of these contaminants. By changing the bonding energy of the surface metal, these nano surface treatments hinder the ability of contaminants to adhere to a surface. These treatments do not affect mechanical, optical, or electrical properties of the treated devices.

The discussion will include technical differences between a "coating" and "surface treatment" and the impact of these differences on a flow process. The paper will highlight environments that are best suited for these nano surface treatments and the different application methods available for treating devices. Data will showcase the performance of nano surface treatments in common applications, such as Coriolis meters, turbine meters, valves, flow and level devices. Producers have seen significant extension in the functional life of these devices and achieved significant operational savings. The paper will discuss how this data applies to other applications such as vessels, chemical reactors, filters, and more.

In conclusion, nano-materials offer new and novel ways to maintain flow through valves, sensitive instruments, and other critical components in a flow line. Surface treatments, using nano-materials are easily applied, have a permanent effect on the surface energy of the metal, and do not hinder the optical, mechanical, or electrical properties of treated devices. Benefits of these treatments include reduced maintenance downtime and cost, improved performance of critical instrumentation and increased reliability of flow meters and valves.
Repurposing of Offshore Oil and Gas Cables for Renewable Generation: Feasibility and Conceptual Qualification
Authors: Mahmoud Ramy Magdy A. , Fayad Hazem , Dodds Paul E.
Published: August 2021

Wind farms are expected to be deployed in the North Sea in increasing numbers and at ever greater distances from land, over the coming decades. Many nearby oil and gas fields have reached or are near the end of their lifespans, and their operators are eager to explore innovative ways to reduce decommissioning costs. One possibility would be to repurpose some of their infrastructures for use by wind farms, which would both delay decommissioning and reduce the wind farm capital costs. This paper investigates the potential for repurposing existing submarine power cores in decommissioned oil and gas fields as transmission cables for offshore renewables.

Offshore power cables generally have longer lifetimes than are needed to deplete hydrocarbon reservoirs. Cable transmission capacity could be too low to provide the main connection to wind farms, but there is scope to increase capacity or use cables as auxiliary connections. A qualification methodology is proposed to assess whether existing cables might be usefully repurposed. Repurposing cables has an impact on renewable project capital expenditure (CAPEX) and levelised cost of energy (LCOE), it also positively affects decommissioning cost and the environment. The qualification methodology provides a cost-effective initial appraisal prior to field testing.
Diverless Revolution - Initiatives and Preliminary Results in the Replacement of Human Diving in Submarine Inspection and Maintenance Operations
Authors: Nunes Romario De Carvalho , Felix Natalia Moreira , Neto Antonio Savergnini , Santana Andre Luiz Bevilaqua
Published: August 2021

This article investigates the diverless trend in the global oil industry, demonstrating relevant aspects of this transition that involves replacing human diving in subsea operations with specific tools and equipment. In this sense, the operational, financial and security aspects related to the theme will be explored. Using the descriptive methodology and in light of Petrobras' case studies, the article aims to correlate the technologies developed to enable diverless operations - including changing the scope of the important Petrobras Route 3 Gas Pipeline project - with increasing operational efficiency and reducing the costs involved in operations. The article also contextualizes the benefits obtained by reducing human exposure and improving safety indicators, a current and relevant topic in the oil industry.
The Challenge of Elastomer Seals for Blowout Preventer BOP and Wellhead/Christmas Trees under High Temperature
Authors: Chen Xuming , Zonoz Ray , Salem Hamid A.
Published: August 2021

It is critically important for elastomer sealing components in blowout preventers (BOP) and wellheads to meet the pressure and temperature rating requirements under the newly released American Petroleum Institute (API) standards, API 16A (fourth edition) and API 6A (twenty-first edition) respectively. Extrusion resistance under high pressure and high temperature is one of the most critical challenge for the elastomer sealing components to meet the above API standards. This challenge is related to the basic properties of elastomer materials and mechanical design of the sealing components. This paper outlines how a simple and low-cost approach was developed to evaluate extrusion resistance of elastomer sealing components, and the correlation between critical tear pressure and extrusion gap of the two elastomers seals was evaluated using a power law equation. This correlation revealed that the above challenges of elastomer sealing components for BOPs and wellheads/Christmas trees is related to the weak strength of elastomers under high temperature and large clearances (extrusion gap) in current designs. New materials and/or new mechanical design to overcome such a challenge were also provided and discussed in this paper.

The paper will help practicing engineers understand the challenge of material selection, mechanical design, and API testing as well as better understand the capability and limitation of sealing components for blowout preventors and wellhead applications under high pressure and/or high temperature (HPHT).
Guyana: Liza Phase 2 Novel Execution to Accelerate Field Development
Authors: Burns Lawson , Allen Theresa , Karlik Jeff , Ding John , Cauthen Rea , Das Mita , Ashley Guy , Szafranski Robert
Published: August 2021

The Liza Phase 2 Project combines a novel execution approach and forward-looking technology components to develop more complex areas of the Liza resource. The project delivers technology to optimize resource development through efficient Subsea, Umbilicals, Risers, and Flowlines (SURF) equipment designs and digital elements to enable future capabilities, such as a fiber optic cable to shore. For a new approach to Floating, Production, Storage and Offloading (FPSO) delivery, the project is partnering with SBM for the first ever use of their Fast4Ward® concept.

The SBM Fast4Ward® program utilizes the Multi-Purpose Floater (MPF) hull design and provides the benefits of a new build FPSO with a reduced project development time similar to that of conversions. With almost double the SURF infrastructure as Liza Phase 1, Liza Phase 2 uses learnings and standardized SURF architecture to deliver one of the industry's largest subsea developments. Establishment of win-win partnerships with the primary contractors to achieve best overall value and strategic use of part number duplication contribute to the overall success.

Based on the work of ExxonMobil proprietary reservoir modelling, infrastructure is being installed to enable Water Alternating Gas (WAG) injection for the complex development while a subsea fiber optic cable enables data to shore for optimized reservoir management and advanced facilities surveillance.

The project is on track to deliver ~2 years after first oil was achieved for Liza Phase 1 by building on design replication and common methodologies where possible. Through thoughtful application of standardization, learnings, and incorporation of new technologies, the project efficiently delivers advanced capabilities to the Liza field. This also enables a "Design One, Build Multiple" (D1BM) approach for future developments in Guyana.
Qualification of a New Multiphase Pump. the Setting of a New Standard
Authors: Hofstad Åge , Olderheim Tarje , Almgren Magnus , Rondon Marianna , Thibaut Edouard , Bibet Pierre-Jean
Published: August 2021

The recent trend in the oil industry is to save CAPEX and exploit every offshore field to increase production and maximize reserves. Also, deeper water and longer step-out is a challenge for new fields. The most adapted technology to unlock these reserves is the use of subsea boosting like a multiphase pump on the seafloor. Subsea boosting has been used for decades with well proven results, but up to now, some limitations in power and lift pressure exist. This new multiphase pump development has increased the potential pressure generation manyfold from the typical ΔP of 50 bar (725 psi) at the beginning of the project.

Developing such a powerful two-phase pump driven by a liquid-filled motor requires a unique combination of expertise in machinery engineering, electrical engineering, fluid mechanics and rotor dynamics. The objective of the co-authors is to share this experience by bringing some insights on what it takes to develop, test, and qualify such specific product. Outlines of the methodology will be described, key results will be detailed, and lessons learnt will be presented.

The new design was fully tested first component-wise and then for a full-size prototype. A wide process envelope was mapped during the final qualification program with 3,000 points tested in the range 2,000-6,000 RPM and 0 - 100% GVF (Gas Volume Fraction). Qualification tests concluded with more than 2,000 cumulative hours.

The main challenges in this program were the development of an innovative multiphase impeller and the qualification of the first MPP (MultiPhase Pump) with a back-to-back configuration. Concerning the motor, the development includes a high speed 6,000 RPM, 6 MW liquid-filled induction motor and a new stator winding insulation cable.

With this new product, the pump market is ready to overcome challenges to produce deeper and further reservoirs in a constant evolutive oil and gas market.
Simulated Full Lifetime Response Data of a Turret-Moored FPSO for Training AI Using HPC
Authors: Lim Ho-Joon , Kim Hyoungchul , Koo Bonjun , Sidarta Djoni Eka
Published: August 2021

Typically, limited operational time and data are available to adequately train artificial intelligence (AI) models for new field developments. Simulation data has the potential to train AI, but it must be sufficiently accurate, reliable and comprehensive. The main objective of this research is to generate and customize response data of a turret-moored Floating Production Storage and Offloading (FPSO) vessel for AI training.

Direct time-domain simulation, covering the entire service life (e.g. 100,000 simulations, each representing 3 hours, for 35 years) of a floating platform, has become practical using High Performance Computing (HPC). In this study, 21-year hindcast Gulf of Mexico environmental data with 3-hour intervals for the Gulf of Mexico are simulated, and the responses of a turret-moored FPSO are analyzed using a fully coupled time domain analysis method. The FPSO and turret are modeled as independent bodies and connected through a bearing connection model, which allows rotation of the FPSO with respect to its mooring system.

The numerical model, which has been validated through model tests, is utilized for simulating the entire service life responses of a turret-moored FPSO. The results provide 61,360 cases of 3-hour time series data with 6 degrees of freedom (DOF) responses for both the turret and FPSO, mooring tensions, and interaction loads between the turret and FPSO. Significantly, the large yaw response, which is a unique characteristic of a turret-moored FPSO, is accurately captured. Moreover, the simulated data set is sufficiently large for AI training, and the real time predictions of a turret-moored FPSO are discussed.
Transformation of Digital Requirements: An Enabler for Successful Complex Projects
Authors: Hudson Abe , Marsh Jim
Published: August 2021

This paper discusses the lessons learned from transforming upstream operational requirements from a document environment into a requirements management tool (database). Operations requirements from upstream practices, procedures, specifications, and guides were migrated from a document centric environment into a requirements management system (data centric). Here, requirements were assigned attributes denoting the organization and accountable operational role that requirement. Many organizations, operating complex offshore procedures, especially where operations are highly regulated, are looking to move their operational requirements from a document centric environment to a data centric environment. This paper highlights some potential pitfalls and mitigation strategies for ensuring a successful migration.
Nanomaterials Improve Polymer-Based Gravel-Packing Fluids at High Temperature
Authors: Prabhu Rasika , Santamaria Juan-Carlos , Vaidya Nirupama , Abivin Patrice , Lafitte Valerie , Gadiyar Balkrishna
Published: August 2021

A gravel packing fluid system was developed for elevated temperature applications above 290°F comprised of xanthan gum and a high-temperature gravel suspension additive. This fluid system has been successfully pumped in four openhole gravel packing operations so far, validating its suitability for Alternate Path gravel packing technology involving shunt tubes. Laboratory qualification testing for this fluid showed excellent gravel suspension, rheology, and breaking profiles for cleanup and minimal damage during production.

Xanthan gels have been used in gravel packing applications for many years. However, by itself, xanthan was unable to suspend gravel at temperatures above 290°F possibly due to onset of thermally activated polymer degradation. This paper demonstrates that gravel suspension ability can be vastly improved with the addition of a recently developed nano-additive. This additive is a specially designed versatile nanosized material that has a proven track record with visco-elastic surfactant fluids in the past. In the present study, we show the successful application of this additive with polymer-based carrier fluids such as xanthan, effectively increasing their application range to 325°F. With the inclusion of this suspension additive, xanthan concentration in the fluid system can also be reduced, which has other potential benefits such as better cleanup after gel break.

Extensive laboratory evaluation for fluid qualification was performed prior to the job. High-pressure/high-temperature (HP/HT) rheology measurements were performed using industry-standard rheometers at various shear rates to match specific viscosity requirements for shunt tube applications. Gravel suspension tests performed using special pressurized cells immersed in oil bath at the required bottomhole static temperature showed improved gravel suspension with the nano-additive. Fluid breaking with conventional oxidative breaker was also demonstrated with viscosity measurements. Formation response tests showed very good fluid cleanup with 90% regained permeability.

Laboratory testing and successful field applications have proven the effectiveness of this new fluid system.
Optimizing Deepwater Rig Operations With Advanced Remotely Operated Vehicle Technology
Authors: McCoy Bernard , MacInnes Peter , Angelidis Diogenes , Collins Robert , Sosa Julio , Rauf Zain
Published: August 2021

In order for capital-intensive deepwater prospects to remain at investment grade potential, it is important the industry achieve meaningful improvement in capital efficiency. Achieving this goal will require a multi-faceted strategy in which advanced new technology and digital transformation will play a determining role. This paper will address the optimization of rig operations through deployment of an advanced Remotely Operated Vehicle (ROV) system that leverages precision robotics and automation technologies; reducing total cost of ownership (TCO) through increased rig productivity, operational certainty and overall utilization.

Current ROV technology faces several key limitations which contribute to both schedule and cost variation. These inefficiencies are a combination of human skill variance, ROV system limitations and reliability. Advanced ROV systems have been deployed on two deepwater rigs to demonstrate that machine vision and precision robotics technologies will radically improve the predictability and efficiency of operations. Comprehensive metrics addressing safety, budget impact, cost avoidance & reduction, inventory reduction & non price TCO have been developed to capture the efficiencies and identify the net improvement to drilling and completion operations and yield outcome-based performance.

An overview of the key deficiencies and limitations of legacy ROV operations will be conveyed, focusing on; i) High dependency on ROV pilot subsea task skills, ii) Worksite efficiency and ROV availability, iii) Restricted tooling capabilities per dive, iv) Rental tooling logistics and cost, v) Equipment reliability at depth, vi) Inefficient tooling changes, and vii) Dive duration and lost time efficiency launch/recovery time. An overview of how the advanced ROV system resolves these issues will be explained. In addition, an explanation of the productivity metrics will be conveyed, supported with data from the active offshore projects. Key conclusions from the data identify that enhanced robotics will achieve the objectives of i) Reducing schedule and cost risks which improve total cost of ownership, ii) Enhancing capability and improved wellsite efficiency, and iii) Increasing subsea data.

The performance issues of legacy ROV operations and associated project cost impact is currently not widely recognized by the offshore drilling community. The realized limitations of such ROV operations and lack of useful performance metrics to identify non-productive time will be explained. The progression in robotic design that drives a new era of subsea robotic efficiency will be conveyed with results from offshore operations, combined with robust metrics that enable significant operational value and cost savings to be attained.
Incorporating Digital Solutions to Foster Greater Remote Engagement with Personnel
Authors: Wilson Lee , Velez Ferdinand , Lim Jason , Boyd Leah
Published: August 2021

Like most business sectors, the oil and gas industry had to adapt to virtual meetings and working from home in the new reality of the global COVID-19 pandemic. This has introduced new complications to completing activities that traditionally require personnel to be on site and collaborate in teams. This paper reviews digital initiatives that allow workers to collaborate virtually on EHS (Environmental, Health, & Safety)-driven practices such as safety audits and engage remotely for improved morale.

Specifically, the paper reviews the recent implementation of digital connectivity solutions for remote workers to join virtual ‘Safety Walk and Talks’ in processing facilities and offshore platforms. It also reviews programs to promote connectivity between workers, including virtual town halls and online coffee-hours conversations.

While these digitally enabled remote engagement initiatives are still relatively new, they have quickly provided benefits to the safe operation of offshore assets and the morale and mental wellbeing of the workforce. The first virtual ‘Safety Walk and Talk,’ which was conducted in Indonesia, brought together a cross-functional team that was split between a few in-person attendees and a majority of people joining virtually from remote locations. While the digital connection was not seamless, this first-of-its-kind virtual meeting proved the concept. The process improves EHS metrics by minimizing travel of teams to and from the site. It also keeps more people out of potentially hazardous work environments and minimizes exposure to coronavirus or other health hazards.

Other digital connectivity measures such as virtual town halls and worker-submitted videos have increased engagement between management, workers, and teams located around the globe. A virtual ‘Coffee Roulette’ program, in which workers spin a virtual wheel that connects them with other employees for informal chats, has allowed people to make new connections and feel less isolated.
From Data to Assessment Models, Demonstrated through a Digital Twin of Marine Risers
Authors: Kharazmi Ehsan , Wang Zhicheng , Fan Dixia , Rudy Samuel , Sapsis Themis , Triantafyllou Michael S. , Karniadakis George E.
Published: August 2021

Assessing the fatigue damage in marine risers due to vortex-induced vibrations (VIV) serves as a comprehensive example of using machine learning methods to derive assessment models of complex systems. A complete characterization of response of such complex systems is usually unavailable despite massive experimental data and computation results. These algorithms can use multi-fidelity data sets from multiple sources, including real-time sensor data from the field, systematic experimental data, and simulation data. Here we develop a three-pronged approach to demonstrate how tools in machine learning are employed to develop data-driven models that can be used for accurate and efficient fatigue damage predictions for marine risers subject to VIV.
Digitally Transforming Offshore Production: Making Low-Manned Brownfield Installations a Reality
Authors: LaGrange Elgonda , Bollinger Brett , Elnaamani Ali
Published: August 2021

This paper outlines an approach for de-manning brownfield offshore production installations. It discusses how the latest advancements in rotating equipment, electrical & automation systems, and digitalization can be applied to reduce operating costs, lower breakeven prices, and extend the lifetime of existing/aging fields.

The approach is value-rather than technology-driven and focuses on prioritizing investments based on return on investment (ROI) to enable low-manned operations as a stepping-stone towards unmanned installations. The paper discusses key facets of a holistic de-manning strategy, including:

Remotely controlled production operations Predictive analytics to reduce unplanned downtime and extend mean time between overhauls (MTBO) Automated inspections Remote collaboration Unified data management Change management

The concepts presented in the paper are derived from the authors’ company's work implementing digital solutions for customers in both onshore and offshore oil and gas, and power generation industries. It also draws on the results of an in-depth onshore field de-manning study that was conducted for a major Middle East national oil company (NOC).
Driving Superior Performance in Brazilian Pre-Salt - The Challenges, Solutions and Achievements of Shell and Providers in Exploratory Pre-Salt Wells in Brazil
Authors: Barrios Enrique , Santos Rafael , Hartmann Robin , Pessanha Vinícius , Neves Romulo Adrien , Pereira Rodrigo Alves , Ribeiro Rodrigo Rodrigues , Schimmelpfennig Thiago
Published: August 2021

The Brazilian Pre-Salt has gained importance as an essential world-class province given its prolific production and thanks to its many challenges, it has incentivized the market to look for better ways to faces these technical challenges safely. This article aims to describe the main challenges faced by Shell and Constellation as well as the approach adopted to improve the operations’ safety and reduce drilling time, significantly reducing the drilling costs in an exploratory campaign in the Brazilian Pre-Salt.

The campaign was based on the buildup of a partnership between the drilling contractor, operator and the main services provider, Halliburton, creating a transparent and collaborative environment, which improved all parties’ ownership and accountability. The application of many processes and techniques such as Step Seven, Stop Work Authority and Design of Work improved safety and efficiency. A precise equipment selection, detailed planning and careful execution with disciplined application of a learning mindset were also paramount to drilling performance.

Four pre-salt wells were drilled in the campaign at Sul de Gato de Mato (2 wells), Alto de Cabo Frio and Saturno prospects with all of them qualifying in terms of drilling time as best in class (BIC), i.e., within the top 5% percentile. In 2019, the GdM3 well was the fastest delivery of a pre-salt well out of the 250+ wells in the region. The well GdM4 drilled in 2020 as part of the same campaign broke the previous record by seven days, being the fastest pre-salt well ever drilled with its 18 dry hole days mark.

The main reason associated with the campaign´s success was the utilization of the DID-PDCA methodology, which promoted the integration of all the workforce in a cycle towards continuous improvement by: (i) carefully selecting the equipment and experienced service providers, (ii) generating detailed plans of the drilling activity and engaging all those involved in the delivery, (iii) establishing and applying a HSE strategy for safety culture enhanced and (iv) constantly monitoring of performance and discussing the next steps.

Along this article a summary of well layout, the drilling phase duration, some of the key performance improvement initiatives as well as how they were generated will be shared.
Energetics and Kinematics of Inertial Oscillations in the Central Northern GOM
Authors: Ivanov Leonid , Ramos Rafael , Gustafson Drew
Published: August 2021

Understanding the physics of generation, propagation, and dissipation of inertial currents is important from a variety of aspects. For the Gulf of Mexico, one such aspect is that these oscillations represent an uncertainty in the measurements and forecasting of the longer-period currents, such as those due to the Loop Current (LC) and meso-scale eddies. The Industry has a practice of applying an ‘uplift’ to estimates of current velocity to account for the effect of tidal and inertial currents in cases when observations or model estimates do not resolve the high-frequency current variability. The value of the ‘uplift’ is assumed to be proportional to the intensity of the low-frequency flow. Our analysis aims at testing whether this assumption is valid by providing a detailed description of the space-time variability, including seasonal changes, of inertial oscillations in the central northern Gulf of Mexico. From the analysis of long-term current profile observations and drifter data we found that, on average, near-inertial oscillations have higher amplitudes outside of the areas of strong low-frequency currents associated with a Loop Current Eddy (LCE). Within the upper 200m of the water column, periods characterized by the downward energy propagation dominate. In the layer below 200m, near-inertial waves propagate upward and downward, and the wave trains cannot be traced to a single source of energy. This suggests near-inertial waves within the main part of the water column are of ‘global’ rather than of ‘local’ origin. For most near-inertial wave generation events through wind forcing, the downward energy propagation could not be traced for any extended period of time and no deeper than approximately 200-m depth. The rate of downward energy propagation in the upper pycnocline is on the order of 10-12 m/day. For the near-inertial currents, the first two Empirical Orthogonal Functions (EOF) contribute only 40% into the total current variability for the period of LCE presence and 52% for the period of benign current conditions. The mode shapes vary within a wide range that, most likely, reflects a random distribution of mode shapes that depend on the lateral geometry of the forcing, mixed layer depth, and stratification.
Development of a Passive Magnetic Radial Bearing System for Electric Submersible Pumps ESPs
Authors: McMullen Patrick , Biddick David , Artinian Herman
Published: August 2021

This development is the result of a DeepStar program to build and test a new radial passive magnetic bearing system (PMB) for downhole tools. While slated for the Magnetic Drive System (MDS) ESP, an advanced high-speed ESP that uses magnetic fields to increase performance, reliability and retrievability, this technology is applicable to conventional ESPs. The PMB supports the motor rotor across large clearances with no physical contact via magnetic fields in the ESP.

An MDS ESP preliminary design was developed, from which the size and integration requirements of the PMB were defined. These requirements guided the analysis, design and testing of the full-scale components. Empirical analysis tools were used for initial iterations in size and performance of the PMB, followed by detailed magnetic finite element analysis (FEA) using commercial validated tools for the final performance prediction. With analytical validation of performance, detail designs were developed and hardware fabricated. Hardware testing was done to validate performance predictions and alignment with system requirements.

The feasibility, preliminary design and analysis of the PMB were conducted in Phase 1 of the DeepStar Program and has continued with the full-scale design, build and test results of Phase 2. PMB performance results include load capability and deflection during static load events, all in relation to validating performance for use in the MDS system. This test data is used to validate the analysis approach used as well as to finalize the integration size of the PMB to meet the performance requirements of the MDS system. With the PMB large (>14mm) clearance between rotor and stator magnets, testing also includes variations in axial and radial position of the rotor in relation to the stator to account for installation variations in the MDS as well as use of sealing materials on both the rotor and stator. Integration is planned for use of the PMB in the MDS, so integration testing is planned to validate performance for each of these areas.

This technology offers a radial bearing that can greatly enhance ESP performance and reliability. The PMB is a contact-less bearing system that does not require lubrication, can operate with large clearances to allow free fluid flow, is easily fully sealed from the environment, has virtually no bearing rotating losses, and has no operating life limits.
Development of Failure Prediction Models for Subsea Blowout Preventers Using Data Analytics and AI
Authors: Machado Rodrigo Chamusca , Leite Fabbio , Xavier Cristiano , Albuquerque Alberto , Lima Samuel , Carvalho Gustavo
Published: August 2021

Objectives/Scope

This paper presents how a brazilian Drilling Contractor and a startup built a partnership to optimize the maintenance window of subsea blowout preventers (BOPs) using condition-based maintenance (CBM). It showcases examples of insights about the operational conditions of its components, which were obtained by applying machine learning techniques in real time and historic, structured or unstructured, data.

Methods, Procedures, Process

From unstructured and structured historical data, which are generated daily from BOP operations, a knowledge bank was built and used to develop normal functioning models. This has been possible even without real-time data, as it has been tested with large sets of operational data collected from event log text files. Software retrieves the data from Event Loggers and creates structured database, comprising analog variables, warnings, alarms and system information. Using machine learning algorithms, the historical data is then used to develop normal behavior modeling for the target components. Thereby, it is possible to use the event logger or real time data to identify abnormal operation moments and detect failure patterns. Critical situations are immediately transmitted to the RTOC (Real-time Operations Center) and management team, while less critical alerts are recorded in the system for further investigation.

Results, Observations, Conclusions

During the implementation period, Drilling Contractor was able to identify a BOP failure using the detection algorithms and used 100% of the information generated by the system and reports to efficiently plan for equipment maintenance. The system has also been intensively used for incident investigation, helping to identify root causes through data analytics and retro-feeding the machine learning algorithms for future automated failure predictions. This development is expected to significantly reduce the risk of BOP retrieval during the operation for corrective maintenance, increased staff efficiency in maintenance activities, reducing the risk of downtime and improving the scope of maintenance during operational windows, and finally reduction in the cost of spare parts replacementduring maintenance without impact on operational safety.

Novel/Additive Information

For the near future, the plan is to integrate the system with the Computerized Maintenance Management System (CMMS), checking for historical maintenance, overdue maintenance, certifications, at the same place and time that we are getting real-time operational data and insights. Using real-time data as input, we expect to expand the failure prediction application for other BOP parts (such as regulators, shuttle valves, SPMs (Submounted Plate valves), etc) and increase the applicability for other critical equipment on the rig.