bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction and Monitoring of Installation of Offshore Foundation Monopiles for Windfarms
Authors: Van Dorp Rob , Moscoso Nicolas , Bielefeld Marcel , Verbeek Gerald
Published: April 2019

Upon recently, most offshore foundations were based on a number of driven piles that were installed with an impact hammer. With the increase in offshore windfarms two major developments have occurred: the shift from jackets to monopiles, leading to increase of the diameter of the foundation piles, and a shift from impact hammers to vibro hammers.

As the use of vibratory hammers is becoming more and more common practice, the need for accurate vibro-driving simulation software has increased, which requires that the soil modelling is enhanced to address soil fatigue during pile driving and to predict reliably the soil behavior and resistance during pile driving. In addition pile driving monitoring, which is routine for piles driven with an impact hammer, needs to become common practice.

This paper addresses advances in soil modelling that allows more accurate pile driving simulation as well as the application of Vibro Driving Analysis (VDA) or Monitoring (VDM) to validate the simulation results. This is illustrated by a case study of the test pile for the Delft Offshore Turbine project, a 28 m long monopile with a diameter of 4 m that was driven 15 m into dense sand layers using a vibro hammer. After some 6 months the pile was extracted, and pile driving simulations and VDA were done both for the installation and extraction phase.
Experimental Investigation on Generation and Development of Shallow Water Flow in Overpressured Sand Formation
Authors: Shi Can , Lin Botao , Jin Yan , Shentu Junjie
Published: April 2019

Shallow water flow (SWF) is a common type of geological hazard in deep-water drilling. It usually occurs in a relatively shallow stratum below mud line (about 450-2500m). When encroached by a drill bit, the substantially over-pressured sand body can generate SWF that may dramatically impair the integrity of the drill string and the associated equipment. However, the mechanism that triggers SWF is lack of detailed understanding, leaving a safe design of drilling through SWF prone strata in suspense. In this paper, through the independent design and development of the shallow water flow simulation device, the damage, and flow mechanism of the sandstone occurred during the SWF events. It can be found through the experiment that in the occurrence of shallow water flow event, there is much sand accumulation around the pressure relief port. The sand body below the pressure relief port is lifted upwards as a whole, and the sand layer above the pressure relief port has a specific amplitude decrease. The findings could not only help understand the SWF process but also build a foundation for subsequent research on prevention and control of SWF incident. In addition, it provides theoretical guidance for improving drilling equipment to ensure that the SWF hazard is adequately controlled.
Performance Characteristics of the NoiseSpotter: An Acoustic Monitoring and Localization System
Authors: Raghukumar Kaustubha , Chang Grace , Spada Frank W. , Jones Craig A.
Published: April 2019

In support of monitoring technologies to evaluate the potential environmental effects of offshore energy devices, this project attempts to ultimately improve upon traditional acoustic sensing techniques by developing a cost-effective compact array of acoustic vector sensors that characterizes, classifies, and provides accurate location information for anthropogenic and natural sounds. The NoiseSpotter consists of three acoustic vector sensors arranged in a three-dimensional array deployed as a seafloor mooring. Each vector sensor measures acoustic pressure and the three-dimensional particle velocity vector associated with the propagation of an acoustic wave, thereby inherently providing bearing information to an underwater source of sound. Here, performance characteristics of the NoiseSpotter are presented, along with an analysis of its abilities as an operational passive acoustic monitoring system to characterize sources of sound. Data are presented from controlled acoustic transmissions in a quiet environment and an energetic tidal channel in the presence of non-acoustic flow noise. NoiseSpotter performance is demonstrated through its modular design, ease of deployment/recovery, ability to remove signal contamination by flow noise and the ability to geolocate acoustic sources of interest.
A Case Study of an Independent Third Party Review of Subsea HPHT Technologies Designed and Qualified by a Joint Development Agreement
Authors: Rettie Stuart Douglas , Badam Srinivas , Urquhart Robert James , Walz Gregg
Published: April 2019

For new High-Pressure High-Temperature (HPHT) subsea technologies deployed in the United States Gulf of Mexico (GoM), the Bureau of Safety and Environmental Enforcement (BSEE) currently requires an Independent Third Party (I3P) review of the design and qualification. When these technologies are developed through a Joint Development Agreement (JDA) and involve a significant scope of new product development, the I3P review can become complex, and a lengthy endeavor. This paper outlines the management lessons learned through a case study of an I3P review performed on a JDA for subsea HPHT production equipment.

In 2014, an Original Equipment Manufacturer (OEM) and four Operators formed a JDA to develop new subsea production technologies for use in the GoM. The OEM has designed the JDA equipment suitable for 20 ksi / 350°F operation subsea, and performed activities to verify and validate the design. An I3P began reviewing the OEM's JDA work in 2016 to verify it meets the acceptance criteria established by industry standards, practices and procedures. Key management lessons from the JDA I3P review's organization, methodology, and practices were studied from an Operator's perspective.

This paper describes the selection of the I3P for the JDA. The selection criterion includes the I3P's qualifications, experience, and resource availability. This paper identifies critical leadership attributes required of the I3P review participants: enforcing ground rules; using a common language across the teams; and deploying robust performance management tools. These attributes drive the convergence of the OEM and I3P review activities. Also discussed, are the importance of a mature OEM document register for timeliness and completeness of document availability for I3P review, and the need for streamlined procedures with a collaborative working approach to manage Findings from the I3P review. It discusses the value of standardizing I3P review reports, to convey the results of verification and validation activities to BSEE clearly and concisely. The paper concludes with identifying some pitfalls to be aware of when executing an I3P review.

The results of studying an ongoing JDA I3P review as described in this paper provide useful guidance for Operators or OEMs in planning and executing I3P reviews of HPHT technology development programs. The case study's key lessons can aid others to implement an I3P review effectively and efficiently for BSEE's acceptance of new HPHT technology.
A Class Perspective for Wind Load Assessment
Authors: Guha Amitava , Boppudi Srimanth , Rousseau Joseph
Published: April 2019

This study describes the purpose, scope, and acceptance criteria for wind load assessments that are used in the Classification of offshore units and installations. Wind loadings are applied as external environmental forces when evaluating afloat stability, structural strength, and mooring system integrity for mobile offshore units and site-specific installations. Existing criteria in the Rules and industry standards are identified to show the usage of the wind loads and their varying characterization depending on purpose, such as time averaging period and vertical speed distribution. The current requirements are placed in historical context based on the development of the offshore Classification Rules over the last 50 years, and the evolution of tools and technology to carry out the computations over that period are discussed.

Practical aspects of calculation and independent analysis are illustrated by applying the standard methodologies in example calculations, using a geometric model that is of similar layout and complexity compared to existing offshore units. Sample calculations are presented as typically performed by Class in an independently developed model, and sensitivity analysis is used to point out areas where results may diverge depending on the approach by the assessor. The effect of these modeling decisions to evaluate wind moment is put in perspective by showing the change in the allowable vertical center of gravity, which relates directly to the deck load capacity of the platform.

The result is a consolidated illustration of the Classification methodology for wind load analysis, which has been uniformly applied to a large number of offshore units and installations over a significant period of time. The importance of common assumptions and approach is highlighted, based on the effect that varying certain parameters has on overall results of the wind load calculation. The resulting impact of wind load changes on the stability, mooring, or structural analysis will be further shown. This will assist in providing visibility to industry on what constitutes a complete report of the wind loads for Classification purposes, how detailed a model should be for basic and detail design purposes, and how to improve confidence in the submission and approval process during design.
Session 46 Phased Deepwater Field Developments - Pros and Cons of Phased Developments
Authors: Duesund Jon Marsh , Martinsen Audun , Fitzsimmons Matthew
Published: April 2019

In light of the deep industry downturn that started in 2014, there was a drastic reduction in the number of deepwater projects being sanctioned. Among the few projects that were sanctioned, many of them were tie-backs or smaller production facilities that potentially can be built out in phases. There are both pros and cons related to this trend of more phased and smaller developments and the purpose of this paper is to highlight these differences. We identify five pros and five cons. The pros are relatively intuitive, e.g. they lower the initial capex, payback period and overall project risk as you are committing fewer resources into the development project. On the other hand, the potential cons are less explicit and typically only visible longer term, including potentially lowering the long-term value creation, limiting the flexibility for future upside projects through e.g. increased/enhanced oil recovery (IOR/EOR) initiatives or tie-backs. By performing some sensitivities, it is possible to give examples where operators may miss some value creation by choosing phased and/or scaled down development solutions. We have looked at three project examples; Buckskin in the US Gulf of Mexico (GoM), Johan Castberg in the Norwegian Barents Sea and Liza offshore Guyana. For these three examples, the results of the sensitivity analysis suggest that overall value creation could have been increased 4-12% if the operators had chosen concepts with higher capacity. However, this increase is contingent on achiveving 20% savings on the capital expenditure (capex per boe) compared to the original concept. Additionally, these enlarged concepts would have created more risks, but from a subsurface and project execution point of view. As such, the pros may outweigh the cons of choosing a more phased and/or scaled down concepts for these examples. Nevertheless, it is important that the industry makes the proper assessments, including longer-term benefits, before making final investment decisions and not overlook potential value creation opportunities.
Hydrate Agglomeration in Crude Oil Systems in Which the Asphaltene Aggregation State is Artificially Modified
Authors: Costa Salmin Davi , Delgado-Linares José , Wu David T. , Zerpa Luis E. , Koh Carolyn A.
Published: April 2019

Some crude oils contain naturally occurring surfactants that avoid hydrate agglomeration. Natural hydrate anti-agglomeration has been linked to different crude oil fractions, including asphaltenes and petroleum acids. Asphaltenes are known to promote the formation of stable water-in-oil emulsions due to their high interfacial activity. The surfactant-like behavior of asphaltenes is directly related to their aggregation state. Asphaltenes are strong interfacial agents when in a colloidal aggregation state, but weak interfacial agents when either precipitated or well dispersed in the bulk oil phase. The asphaltene aggregation state may be artificially modified (changing the interfacial activity) by mixing crude oil with heptane-toluene mixtures (heptol). This work investigated the influence of the asphaltene aggregation state on gas hydrate agglomeration. Results show that the hydrate dispersing capability of crude oils is highly dependent on the asphaltene aggregation state. For instance, if asphaltenes were induced to be solubilized into the bulk oil phase (i.e. toluene rich heptol), the hydrate dispersing behavior was diminished. However, when asphaltene precipitation was induced (i.e. heptane rich heptol), gas hydrates were efficiently dispersed. These new findings could have important implications for the ultimate implementation of novel hydrate management strategies that can eliminate/reduce the need for external interventions and hence minimize capital and operational expenditures.
Method Uncertainty for Five Axial Pile Capacity Design Methods
Authors: Liu Zhongqiang , Nadim Farrokh , Lacasse Suzanne , Lehane Barry , Choi Young Jae
Published: April 2019

The paper describes two approaches for deriving the mean, standard deviation and probability density function of the method uncertainty for five axial capacity pile design methods, namely the API, Fugro, ICP, NGI and UWA methods. A new unified database of pile load tests recently developed in a joint industry research project (Lehane et al., 2017) is used for the quantification of method uncertainty. The focus of this paper is on the statistical description of the method uncertainty parameters for each of the pile design methods for predicting the axial capacity of piles in sand and in clay. Probabilistic calculations of the axial pile capacity for typical offshore piles using the above five design methods (API, Fugro, ICP, NGI and UWA methods) showed that method uncertainty is a major contributor to the uncertainty in pile foundation capacity. The method uncertainty has therefore a strong influence on the calculated annual probability of failure, and thus on the associated safety level. Establishing the statistics of the error in a capacity prediction model from the measured values (Qm) in pile load tests and the calculated values (Qc) of pile capacity requires careful consideration of several factors. Issues of importance to the derivation of method uncertainty statistics include the effect of different sized databases for the different pile design methods, the effect of case histories with particularly low Qm/Qc values and the possible dependence of method uncertainty on pile length and/or pile diameter. The paper presents two different interpretations for the characterization of method uncertainty and demonstrates their application through a case study for an offshore piled jacket. The effect of method uncertainty on the calculated annual probability of failure is illustrated.
AUV Integrated Cathodic Protection iCP Inspection System – Results from a North Sea Survey
Authors: Kowalczyk Matthew , Claus Brian , Donald Craig
Published: April 2019

The OFG AUV non-contact integrated Cathodic Protection (iCP) inspection system enables a fast and reliable approach to monitoring the state of cathodic protection systems on subsea pipelines. By measuring the electric field, the system monitors directly the change in electrical currents in the pipeline due to anodes or damage. This approach allows for improved monitoring of anode energy remaining, predicts anode end of life earlier than stab methods alone and pinpoints problem areas on the pipe that need attention. When combined with the camera imaging, multi-beam measurements, synthetic aperture sonar (HISAS), and chemical sensors, the OFG AUV iCP system provides a compelling set of measurements for pipeline cathodic protection monitoring and pipeline inspection.

The advantage of the OFG AUV iCP system over traditional ROV CP systems is the speed with which these surveys can be undertaken, coupled with the dramatic increase in sensitivity which is approaching 100 times the sensitivity of the traditional ROV CP survey systems.

Ocean Floor Geophysics (OFG) has a successful history of developing numerous magnetic and electric field instruments for ROVs, AUVs and deep-tow systems. Based on the success of these programs, and in collaboration with ISES Technical Services (ISES), OFG & ISES have developed an electric field measurement system which mounts onto a pipeline inspection AUV.

Initial testing of the system in 2017 on OFG's 3000m depth rated Hugin AUV "Chercheur" demonstrated that the intrinsic electrical noise of the "Chercheur" with motors and all survey sensors running, was well below the threshold needed to successfully measure CP signals from the AUV. This was further supported through the development of a first principles model of the electrical fields generated around a generic cathodically protected pipeline.

These supporting measurements and calculations led to the first operational field test of the system on a North Sea pipeline in April 2018. During these trials we were able to demonstrate the responsiveness of the system to the cathodic protection currents in the pipe at a variety of ranges and orientations up to 10 meters distance from the pipe. Furthermore, by performing repeated surveys of sections of the pipeline in both directions, we were able to confirm the repeatable detection of extremely small electric field gradient signals (less than 0.025μVrms/cm difference). The results show levels of sensitivity and detection hitherto unattainable using any other currently available CP survey method. These measurements were taken concurrently with all the other onboard survey sensors running, including the HISAS, Sub-bottom, Multi-beam, Camera system, and USBL, while running at the nominal survey speed of the vehicle of 3-4 knots.
Importance of Wind Loads for Floating System Designs
Authors: Wang Tao , Wu Yongyan , Løken Rolf , Haug Nora , Eide Rolf
Published: April 2019

Wind represents a driving factor for floating system designs, not only for stability, but also for platform global performance including offset, heel and airgap, and thus for mooring, riser/umbilical, structure, topsides equipment and personnel habitability. Wind load evolves as metocean criteria, topsides layouts, design requirements, and estimation methods, and can be in continuous development from concept, design, execution to operation phases. The impact needs to be considered from operability to survivability of floating systems.

A case study of semi-submersibles in worldwide regions will be considered. It is first developed a semi-submersible in the Gulf of Mexico for hurricanes up to 1,000-year return period. Wind speeds in other representative locations worldwide, i.e., the North Sea, and offshore Northwest Australia, are then applied to reconfigure the semi-submersible hull and mooring. The impacts of wind loads are evaluated by changing the wind speed and associated wind profile, but maintaining the other design parameters. The North Sea case is for relatively less severe winds of up to 10,000-year storms, while the offshore Northwest Australia case is for strong tropical winds of up to 10,000-year cyclones.

The hull configuration, including main dimension, displacement, GM, and mooring sizing, are compared for the worldwide cases. For the Gulf of Mexico case, wind load is not only crucial for stability in 100-year environment, but also for survivability in 1,000-year hurricane. Comparably, wind load governs the North Sea case for stability although its 100-year wind speed is less severe, while 10,000-year cyclone wind is critical to survivability for the offshore Northwest Australia case. For mooring system, wind contributes to the majority of environmental loads, especially for the offshore Northwest Australia case. It is presented as a result of wind speed, and can be used to interpret uncertainty in wind load estimation from empirical method, model testing, CFD and design requirements.

This paper evaluates the impact of wind loads for floating system designs from operating, extreme to survival conditions, identifies the governing factor in worldwide regions, and provides a view of systematic approach to the integrated system.
Subsea Demulsifier Injection to Enhance Crude Oil Production in Offshore Brownfields - A Success Case
Authors: de Oliveira Marcia Cristina Khalil , Alevatto Monica , Sampaio Tatiana Pitchon , Dias Plínio Martins
Published: April 2019

In Brazil oilfield scenario, there are large, clearly identified brownfield sites, many of which with high additional oil production potential. The lifting costs and conventional breakeven price per barrel associated with an existing producing field offshore, even those in decline and requiring some recompletion & workover jobs, are – in many situations - less investiment demanding than brand new greenfield development.

The formation of water in oil (W/O) emulsions is ubiquitous in oilfield production. As the water commingled in crude increases, the emulsions' stability and viscosity also increase, thence generating flow restrictions due to higher friction losses. The subsea demulsifier injection has proven to be an interesting alternative to overcome this flowing constraint in mature wells, thus maximizing the productive capacity of existing brownfields. This paper presents some results and challenges faced to implement the routine of subsea demulsifier injection, from the development of testing protocols to come up with a tailor-made chemical solution, to the hurdles associated to chemical injection through subsea umbilical- and gas lift-lines.
Libra's FPSO - Conceptual Design Challenges
Authors: Queiroz Fabio Vieira de , Araujo Fernando B. C de , Fernandes Mylene Marques , Vaz Juliana Casaccia
Published: April 2019

This paper presents the strategy behind the conceptual design for Libra FPSOs and the technologies being studied to be applied in the future. Considering new reservoir conditions when compared to other Pre-Salt areas in Brazil, such as high GOR, high CO2 content and high productivity wells, surface facilities team have faced new challenges to define the optimum process plant configuration. Concerns related to topside weight and footprint had to be addressed since the early project phase to make sure that the FPSO would be able to operate safely with high production efficiency in a very restricted area.

Right after Libra block contract signature, Libra Project Team elaborated the documentation to lease the first FPSO (EWT FPSO Pioneiro de Libra) and started conceptual studies for the design of the FPSOs that will develop the production of the field.

Besides the economic benefits related to the increase of the oil capacity, the conceptual studies at an early stage of the field development provided the project team more confidence regarding lead time and technical aspects of the FPSO. It is expected that new technologies development will add more value to the projects in the near future.
Stones - The World's First 15 Ksi Ultra-Deepwater Subsea Pump
Authors: Småland Hagland Arill , Skaar JC
Published: April 2019

Stones is a phased development that began producing in September 2016 from two subsea wells tied back to an FPSO. Full-field development includes six additional wells from two connected drill centers, and a subsea boosting system to increase production and extend the life of the field.

This paper describes the technology qualification program (TQP) and execution experience, including the development, delivery and installation of the world's first ultra deepwater subsea boosting system. The paper also addresses the lessons learned from the project, from component qualification and engineering through to manufacturing and testing.

The Stones field is located in the Walker Ridge area, approximately 200 miles southwest of the Louisiana coast. It consists of eight ultra-deepwater blocks at 9,579 feet water depth. As the operator, with 100% interest in the field, Shell announced its final investment decision in 2013. With reservoirs located at extreme depths, at more than 29,000 feet, subsea boosting was identified in the original project execution plan as a means to enhance recovery due to rapidly decreasing reservoir pressures.

Multiple technology gaps were identified to meet the high-pressure, high-temperature (HPHT) design parameters for Stones. With a targeted design pressure of 15,000 psi, design temperature of 300 °F and nearly 10,000 feet of water depth, an extensive Technology Qualification Program (TQP) was executed to close these gaps. Six workstreams were developed to qualify the first article pump; these included valves and connectors, barrier fluid system, power system and controls. This was the start of a close cooperation between the operator and the pump system provider, whose common goal was to deploy the world's first 15 ksi ultra-deepwater pump. Following the TQP, in 2015, an engineering, procurement, and construction (EPC) contract was awarded that included a pump station with two 2.9MW pumps and a topside power drive system.

The pump system has been through an extensive execution and test phase that was completed without injuries. The complete system was handed over to the operator and has been partially installed.

The Stones boosting system has a daily production capacity of 60,000 bpd and will enable the operator to maintain and extend production at the field. Once the pump system is put into operation, it will significantly increase recovery at the field.
Aasta Hansteen Subsea Production System for Deep Water and Harsh Environment
Authors: Lindseth Severin , Røsby Elling , Vist Brynjar , Aarnes Knut Axel
Published: April 2019

The Aasta Hansteen Subsea Production System is a part of a new major deep water gas development located in the Norwegian Sea, north of the Arctic Circle and 300 km from shore, west of the city of Bodø in Norway. With a water depth of 1300m, this development is a new water depth record in Norwegian waters and it is characterized by its remote location and harsh environment.

The objective of this paper is to present the concept selections, technology development, design and fabrication for the subsea production system including umbilical and workover system. The paper demonstrates the importance of solid preparation in early phase planning, continuous implementation of lessons learned and an extensive test program in order to verify the new technical solutions for the Aasta Hansteen subsea deepwater development. This included development of a new mono-pile "toast rack" template designed for guideline less installation of manifolds and X-mas tree systems. This paper also presents a new deep water Workover system, involving an extensive qualification program and several new technical features such as a new safety joint, heave compensator and automated make-up of riser joints and more, in order to improve operational efficiency and increase safety under given challenging conditions. The paper also addresses a full scale wellhead testing in order to verify the design for fatigue performance.

Several novel technologies were qualified and implemented as part of the Aasta Hansteen Subsea Production System to adapt to deep water operations, to enhance HSE performance and improve efficiency of the system. The experience is that the new technologies and new system solutions have improved HSE performance, operational performance and installation friendliness.
BOP Pressure and Flowrate Conditions During High Pressure Gas Kick Control
Authors: Omrani Ala Eddine , Franchek Matthew Albert , Tang Yingjie
Published: April 2019

Vertical upward multiphase flow through a blowout preventer (BOP) during a gas kick event produces complex fluid flow transients. Further complicating these transients is the fluid phase interactions during BOP closing event. The resultant pressure and flowrate transients are critical parameters that influence the BOP design and should be used to estimate if the BOP can close-on/control a kick event. In this paper, a hydro-mechanical two-phase flow model is developed to predict the fluid pressure and flowrate conditions for fully open and closing BOP during a gas kick. The case of a 20,000 psi reservoir is investigated along with a wel depth, from the rig floor to the borehole, ranging from 10,000 ft to 20,000 ft. The results illuminate the dependence of model-based BOP pressure rated design on the formation productivity index during a gas kick event. Furthermore, using a model-based approach for determining such information is essential in the development of next generation pressure control equipment standards and equipment certification, risk minimization to drilling crew and rig assets and reduction of well intervention frequency. High pressure definition based on pore pressure and/or BOP rated working pressure are discussed as well.
Characterizing Smart Cement Modified with Styrene Butadiene Polymer for Quality Control, Curing and to Control and Detect Fluid Loss and Gas Leaks Using Vipulanandan Models
Authors: Vipulanandan C. , Panda G. , Maddi A. R. , Wong G. , Aldughather A.
Published: April 2019

In this study, commercially available styrene butadiene rubber (SBR) polymer up to 3% was added to the highly sensing chemo-thermo-piezoresistive smart cement with a water-to-cement ratio of 0.38 to investigate the effects on the sensing properties. Series of quality control, curing and high pressure high temperature (HPHT) experiments were performed to evaluate the smart cement behavior with and without the SBR polymer. Addition of 1% and 3% SBR polymer increased the initial resistivity by 4% and 12% respectively and hence this parameter can be used for quality control in the field. Vipulanandan p-q curing model was used to predict the changes in resistivity with curing time. Addition of 1% and 3% SBR polymer also increased the compressive strength of the smart cement by 18% and 32% after 1 day of curing respectively, The piezoresistivity of smart cement with the addition of SBR polymer after 1 day of curing was over 500 times (50,000%) higher than the regular cement failure strain of 0.2%. The Vipulanandan p-q piezoresistivity model also predicted the experimental results very well. Addition of SBR polymer reduced the fluid losses 30 minutes and 24 hours after curing. The fluid loss was predicted using the Vipulanandan fluid loss model and compared it to the API model. The smart cement with and without SBR polymer detected the gas leak during initial slurry condition and after solidification. Addition of SBR polymer reduced the gas leak. During the gas leak in the piezoresisitive smart cement slurry the resistivity change was positive and for the solid smart cement the resistivity change was negative. During gas leak in the smart cement slurry the resistivity increase was about 45% and it reduced to 30% with the addition of 3% SBR polymer at pressure gradient of 2000 psi/ft. During gas leak in the solidified smart cement the resistivity reduced, opposite to the piezoresistive response to compressive stress, by about 30% and it reduced to 12% with the addition of 3% SBR polymer at a pressure gradient of 2000 psi/ft. Vipulanandan fluid flow model, generalized Dary's Law, predicted the non-linear responses of gas leak velocity (discharge per unit area) to the applied pressure gradient. Also electrical resistivity changes can be used to predict the gas leak velocity in the smart cement with and without SBR polymer.
The Impact of Real-Time Data in Improving the Efficiency, Safety and Productivity of Wells During the Installation of Lower Completion Assemblies in the Complex Deepwater Environment
Authors: Hawthorn Andrew , Fang Lei , O'Malley Ed
Published: April 2019

As wells have become deeper with more highly complex well trajectories and tighter mud weight windows, there has been an increase in the amount of Non Productive Time associated with installing lower completion assemblies. One of the key issues in safely and efficiently installing these complex assemblies is that, as these wells have become more complex, the traditional methods of utilizing surface measurements and extrapolating or modeling what is actually happening downhole has started to run into problems. Models for torque and drag and hydraulics that worked in shallower and less complex wells with large pressure windows often fail to actually predict what is happening downhole, leading to extreme inefficiencies and sub-optimal or in extreme cases complete failure of the installation. In certain circumstances surface data and models may indicate almost the exact opposite of what is actually occurring downhole.

This paper will demonstrate through case histories in the complex deepwater environment the use of an easy to deploy acoustic telemetry and measurement network that can be run in conjunction with any lower completion assembly to minimize these risks and to optimize the workflows. Data will be shown from the full range of lower completion operations including TCP gun runs, displacement operations and throughout the actual fracing operation itself. This system is completely wireless and can send data through the wall of regular drillpipe without requiring any modification of surface or downhole equipment. Data can be provided back to surface irrespective of fluid, flow or formation type and also during tripping in and out of the hole. Downhole and along string measurement of weight, torque, internal and external pressures and temperatures provide the key data allowing real-time decision to be made on what is actually happening downhole.

The case histories will show how material gains were made by using and acting on this real-time data leading to safer, more efficient and in some case enhanced productivity from these wells.

This paper will show how this real-time downhole data is now readily available and how it has been used to solve problems and optimize the efficiency of operations throughout lower completion installation. Real-time downhole data, which has revolutionized the drilling of wells in the last couple of decades, is now for the first time available to solve the complex issues associated with lower completion operations. If this access to real-time downhole data provides even half of the gains in efficiency and safety seen in the drilling environment, moving forward huge gains may be realized throughout completion operations.
Self-Supervised Subsea SLAM for Autonomous Operations
Authors: Marques Filipe , Costa Pedro , Castro Filipa , Parente Manuel
Published: April 2019

The Earth’s surface is mostly water-covered and the ocean is the source of a significant slice on natural resources and renewable energies. However, only a small fraction of the ocean has been surveyed. Being able to estimate the 3D model of the environment from a single video eases the task of surveying the underwater environment, saves costs and opens doors to autonomous exploration of unknown environments. In order to estimate the 3D structure of a vehicle’s surrounding environment, we propose a deep learning based Simultaneous Localization and Mapping (SLAM) method. With our method, it is possible to predict a depth map of a given video frame while, at the same time, estimate the movement of the vehicle between different frames. Our method is completely self-supervised, meaning that it only requires a dataset of videos, without ground truth, to be trained. We propose a novel learning based depth map prior using Generative Adversarial Networks (GANs) to improve the depth map prediction results. We evaluate the performance of our method on the KITTI dataset and on a private dataset of subsea inspection videos. We show that our method outperforms state of the art SLAM methods in both depth prediction and pose estimation tasks. In particular, our method achieves a mean Absolute Trajectory Error of 1.6 feet in our private subsea test dataset.
Updated Case Study: The Pursuit of an Ultra-Low Manned Platform Pays Dividends in the North Sea
Authors: Settemsdal Stig
Published: April 2019

The use of a unique, data-driven approach to remote condition monitoring of equipment maintenance has enabled a major offshore E&P producer to build and operate a a low-manned platform — a key step in its strategic goal to reduce per-barrel production costs to below $7. The field is 112 miles (180 km) off Norway’s coast, with the platform drawing first oil in December 2016. In January 2019 — after operating identical offshore and onshore platform control rooms — the company started conducting remote condition monitoring of platform machinery exclusively from its control room onshore in Trondheim, Norway, 620 miles (1,000 km) away. With the remote equipment condition monitoring done onshore, the operator is better able to optimize maintenance work and schedules. At the same time, it has contributed to a big reduction in the number of offshore personnel otherwise required, reducing operating costs and personnel risks substantially. In May 2018, Siemens entered into a long-term partnership with the operator to continue developing digital solutions in a closed-loop lifecycle approach, utilizing the digital twin concept from pre-FEED and FEED stages through construction, commissioning, and operations, with operations expected to continue for a minimum of 20-years. This paper will provide an update to a 2018 OTC conference presentation when this use case was introduced. Last year’s paper was based on operations and observations during 2017, the platform’s first full year of operation.
Life Extension of the Risers Used for the Hoover DDCV in Gulf of Mexico
Authors: Yu Chenteh Alan , Cheng Yongming , Yang Guangqiang , Carballo Manuel R.
Published: April 2019

This paper investigates life extension of the risers used for the Hoover DDCV (a classical Spar) in GoM, based on the latest technology and monitored data. Deepwater development in Gulf of Mexico (GoM) started about two decades ago. It is the time to evaluate the global integrity of the riser systems and explore the possibility of life extension in a structured and systematic way.

A Deep Draft Caisson Vessel (DDCV), has been keeping up its class services for the past 17 years since it was installed in 2000. It was expected to extend the riser design life by 10 more years. This paper showed the life extension verification process starting from the initial planning, reviewing of the original design document, gathering and analyzing production and offshore measured data and finally to offshore focused underwater inspection. It introduces the methodology to assess the integrity of Steel Catenary Risers (SCRs) and Top Tensioned Risers (TTRs) used for the DDCV. An independent global performance was analyzed by utilizing latest environmental data, as-built information, measured VIM motion data and the latest analytical tools. It computes the riser global performance including dynamic strength and fatigue with the contributions from wave fatigue, VIM and VIV. The factored riser fatigue life is provided with the original safety factors to meet the intended 10 more years of service life.
Operators Optimize High-Pressure/High-Temperature and Ultrahigh-Pressure Perforation Strategies Using Laboratory Testing
Authors: Grove Brenden , DeHart Rory , McGregor Jacob , Dennis Haggerty , Christopher Chow
Published: April 2019

Multiple perforation laboratory programs have been conducted during recent years to support high-pressure/high-temperature (HP/HT) and ultrahigh-pressure (UHP) oil and gas field developments at various offshore locations globally. This paper highlights six such projects that supported activities within the Asia-Pacific, North Sea, and US Gulf of Mexico (GOM) (both Miocene and Lower Tertiary) regions. Each program was designed and conducted in collaboration with an operator and field operations personnel to help reduce potential risks, improve operational efficiency, and optimize well performance across a variety of challenging environments.

Laboratory experiments were based on API RP 19B Sections 2 and 4, with test conditions customized to match specific downhole environments of interest (rock and fluid properties, stress, pressure, temperature, and flow scenarios). Matching downhole conditions at the laboratory proved important because this yields results that can be quite different from those obtained at surface (or scaled) test conditions. Reliable estimations of field perforation skin, sanding propensity, and the effectiveness of subsequent stimulation operations depend on realistic perforation and flow data obtained at relevant downhole conditions. The overriding goal for test design is to create and expose the laboratory perforation in an environment that matches its field counterpart as closely as possible. Beyond obtaining accurate flow data for skin and/or sanding propensity determination, post-test diagnostics, such as computed tomography (CT) and optical techniques, provide additional essential insight into the characteristics of the perforation tunnel, core interior, and the hole through the casing and cement.

Results from these various programs were used to confirm or, in some cases, guide the field perforating strategy.
Un-Manned Minimal Floating Platforms
Authors: Beyko Eleni , Sablok Anil , Pegg Mathew James
Published: April 2019

A normally un-manned minimal floating platform can be used for several applications to support subsea development. The applications include enabling Long Subsea Tiebacks by supporting power generation and distribution equipment, when the host facility doesn't have excess power capacity (Power Buoy) or the required footprint and space to support the required power distribution hardware or locate the distribution equipment to distribute the power imported from shore. It can also serve as a partial processing host with functionality ranging from Chemicals and Artificial Lift all the way to Multi-Phase Pumping or Gas Compression, as required.

An un-manned floating platform can be a cost-efficient solution, where the economics of a very Long Subsea Tieback or a Host Facility with full processing capacity become prohibitive for developing small to medium size fields. The substructures for these platforms have reduced and simplified systems resulting in lower Capex, Opex and minimal maintenance requirements. This platform is safer to operate than conventional host platforms because it is un-manned, and it also deploys robotics and remotely controlled equipment, using the latest advances in digital, robotics, and autonomous control technologies.

The paper reviews the different floating unmanned minimal platform configurations that are designed for this purpose. The following aspects of the normally un-manned floating platform are discussed:

Functionality Cost-Efficient Design alternatives Construction/Installation efficiency Operations/ Maintenance principles

Possible applications of the normally un-manned floating platform include small to medium size fields, remote gas fields requiring compression to export gas to shore that would otherwise prove to be un-economical to develop. The normally un-manned floating platform helps improve the development economics and the operational safety of these fields. The industry's response to the oil price slump in the past few years combined with the latest advances in technology led to the evolution of these minimal unmanned floating platforms.
Citrullination Controls Dendritic Cell Transdifferentiation into Osteoclasts
Authors: Krishnamurthy Akilan , Ytterberg A. Jimmy , Sun Meng , Sakuraba Koji , Steen Johanna , Joshua Vijay , Tarasova Nataliya K. , Malmström Vivianne , Wähämaa Heidi , Réthi Bence , Catrina Anca I.
Published: April 2019

An increased repertoire of potential osteoclast (OC) precursors could accelerate the development of bone-erosive OCs and the consequent bone damage in rheumatoid arthritis (RA). Immature dendritic cells (DCs) can develop into OCs, however, the mechanisms underlying this differentiation switch are poorly understood. We investigated whether protein citrullination and RA-specific anti–citrullinated protein Abs (ACPAs) could regulate human blood–derived DC–OC transdifferentiation. We show that plasticity toward the OC lineage correlated with peptidyl arginine deiminase (PAD) activity and protein citrullination in DCs. Citrullinated actin and vimentin were present in DCs and DC-derived OCs, and both proteins were deposited on the cell surface, colocalizing with ACPAs binding to the cells. ACPAs enhanced OC differentiation from monocyte-derived or circulating CD1c+ DCs by increasing the release of IL-8. Blocking IL-8 binding or the PAD enzymes completely abolished the stimulatory effect of ACPAs, whereas PAD inhibition reduced steady-state OC development, as well, suggesting an essential role for protein citrullination in DC–OC transdifferentiation. Protein citrullination and ACPA binding to immature DCs might thus promote differentiation plasticity toward the OC lineage, which can facilitate bone erosion in ACPA-positive RA.
Sarcopenia in the elderly: from clinical aspects to therapeutic options
Authors: Bianchetti Angelo , Novelli Andrea
Published: April 2019

Sarcopenia is a major contributor to the risk of physical frailty, functional decline, poor health-related quality of life and premature death in older people. Sarcopenia can be considered a geriatric syndrome. The term sarcopenia indicates the loss of muscle mass that accompanies aging. Muscle mass declines with aging process with differences between subjects in relation to the presence of chronic diseases, to lifestyles habits (mainly diet and physical activity), to cognitive status. Sarcopenia in the elderly is associated with poor health outcomes, such as falls, disability, loss of independence, and mortality; however, it is potentially treatable if recognized and intervened early. The prevalence of sarcopenia rates between 5% and 13% in community-dwelling older people aged 65 years and over, and is higher in those 80 years and older (20-25%). The cause of sarcopenia is generally thought to be multifactorial, with environmental causes, disease triggers, inflammatory pathway activation, and a large number of cellular and biochemical abnormalities. Resistance training and amino acid supplementation are a recommended practice for the prevention of sarcopenia. The essential elements for the management of the sarcopenic patient are the recognition of a condition of frailty, an accurate multidimensional geriatric assessment, with attention to cognitive problems, mood, functional problems, living conditions, using standardized instruments. Combining exercise with some pharmacological compounds such as β- Hydroxy-β-methylbutyrate (HMB) and dietary supplements (including proteins, aminoacids and vitamin D) may exert a beneficial effect on older adults thus influencing the progress to sarcopenia. The recommended daily amount of protein is greater for older people. Vitamin D and leucine enrichment seems mandatory in order to improve muscle mass and lowerextremity function among sarcopenic older adults. There are some evidences that collagen peptides in this setting might be even superior to whey protein in promoting muscle growth and increasing the mobility.