bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost-Benefit Analysis and Comparisons for Different Offshore Wind Energy Transmisision Systems
Authors: Silva-Rodriguez Jesus Angel , Lu Jin , Li Xingpeng
Published: April 2023

This paper investigates how to efficiently and economically deliver offshore energy generated by offshore wind turbines to onshore. Both power cables and hydrogen energy facilities are analyzed. Each method is examined with the associated proposed optimal sizing model. A cost-benefit analysis is conducted, and these methods are compared under different scenarios. Three long-distance energy transmission methods are proposed to transmit offshore energy onshore, considering the capital/operation costs for related energy conversion and transmission facilities. The first method that only deploys power cables is a benchmark method. The other two methods utilize a hydrogen supercenter (HSC) and transmit offshore energy to an onshore substation through hydrogen pipelines. For the second method, offshore wind power is distributed to the HSC and then converted into hydrogen using electrolyzers placed at the HSC. For the third method, electrolyzers are placed at offshore wind farms connected to HSC with low-pressure hydrogen pipelines. An offshore scenario including three wind farms located in the Gulf of Mexico and one onshore substation is used as the base test case. Numerical simulations are conducted over a planning period of 30 years using the proposed optimization models for each method separately. Simulation results show that the proposed hydrogen-based methods can effectively transmit offshore energy to the onshore substation. The distances between the wind farms can influence the selection and configuration of the offshore wind energy system. Moreover, the proposed study analyzes the cost and benefits for various systems with different energy carriers. It can also suggest which method could be the best candidate for offshore energy delivery system under which scenario and demonstrate a promising future for offshore wind power generation.
Offshore CCS: Addressing Current Barriers for Storage Implementation in Geological Formations
Authors: Araujo de Itriago Yani Carolina , Swearingen Jerry Wayne
Published: April 2023

Carbon Capture and Storage (CCS) has long been considered as a potentially means for reducing greenhouse gas emissions from carbon-intense industrial and power generation sources. Over the last few years, there has been intense discussion about the implementation and massification of CCS as a key technology to achieve the Net Zero goal in the decarbonization era. However, the number of projects implemented globally strictly for CO2 storage is relatively small compared to CO2 utilization schemes such as Enhanced Oil Recovery (EOR) programs. This is due to the challenges faced when using geological formations only as a storage vehicle for CO2. Therefore, it is necessary to understand the factors, in addition to economic constraints, that have slowed the massification of the process, especially in offshore storage implementation.

To identify the key factors for a successful implementation of an offshore CCS project, a critical analysis of 42 offshore CSS projects in different stages together with a survey using professional networks were performed. The study started with the identification of key projects scheduled/planned or in the implementation stage worldwide, followed by the review of available technical and economic data, the status of project implementation, from permitting to field development, and finally an analysis of the collected data from the survey.

From the analysis, key factors to implement CCS offshore were identified and discussed. High costs, complex and non-standardized regulations, and lack of governmental incentives in many countries are key factors in lack of offshore CCS implementation. CCS solutions are available currently for onshore projects, but solutions for pipeline or commercial vessel transport CO2 are still being tested with an implementation expected in the near future.

In-depth characterization of the geological formation planned for storage is critical, therefore advanced tools and techniques are required. It is necessary to validate existing models and simulation models for offshore storage and to develop new tools for low-cost monitoring systems. Critical factors for offshore CCS implementation include the identification and development of technologies to reduce operative costs; development of professional skills for field implementation; use of digital technology to improve data processing; improvement of exiting offshore infrastructure; and the engagement of public and private sectors to reduce the timeline for CSS offshore implementation. Based on the current status of CCS projects, actions to close the existing barriers and minimize risks for offshore implementation are recommended.

This paper offers a critical analysis of the requirements for offshore CCS implementation including an overview of projects currently in operation and projects in planning phase along with a technical assessment of the barriers that make offshore CCS projects less advantageous in industry.
Small Deformation Finite Element Analysis of Spudcan Penetration in Multi-Layered Soil
Authors: Radwan Ahmed M. , El-Araby Ibrahim A. , Tolba Ehab R. , El-Gendy Mohmaed M.
Published: April 2023

Using the press-replace technique, a recently developed finite element method depending on the criteria of the small deformation analysis SDA, to investigate the soil-foundation interaction of the Jack-Up rig with Spudcan during its proceeding to achieve stability installation in Multi-Layered soil. The analysis has been implemented and compared with previously published cases, which has been done experimentally and by using large deformation finite element analysis.

The Press-Replace technique PRT is mainly has been developed able to capture the Spudcan proceeding through the multi-layered soil specifically in cases of penetrating through soft soils by simulating the possible squeezing accompanied by the back-flow phenomenon, which happens for the soft soil during the installation. The considered analysis criteria have been explicated. The results provided an effective expectation of the soil-structure interaction validated by the previous experimental and numerical results. Depending on the detailed analysis steps provided, engineers and researchers can use it to make the needed analysis for similar case studies.

The small deformation analysis SDA has been operated on six cases of multi-layered soils and compared to the previous experimental and numerical results. The variety of investigated cases was depending on the type of upper layered, either it was a soft to moderate clay layer or a sand layer. The two main criteria have been considered in the current analysis, which is the backflow of clay and the back-fill of sand. As the analysis theory depends mainly on the geometry update, the simulation steps of these two criteria have been provided in detail. That control has been applied, by observing the soil movement behavior of the previous experimental outcomes. Four cases with upper clay soil and other two cases with upper sand layers have been investigated and compared to previous experimental and numerical results. By controlling these two states of the upper soil layer, it can be obtained the different simulation steps in the analysis in the condition of the existing upper layer is sand or clay. The analysis provided shows a good comparison of stability depth to the previous results. Furthermore, it gives a very close evaluation behavior to the previous experimental results.

This approach numerical method provides a tool for the engineers to use the Press-Replace technique PRT, which is a smooth and fast numerical technique compared to the other numerical methods, to investigate and obtain the Spudcan penetration through similar cases of multi-layered soil.
Comparison of Decarbonization Pathways for Offshore Platforms: Technology Solutions to Address Key Implementation Challenges
Authors: Araujo Fresky Mariela G. , Araujo de Itriago Yani Carolina
Published: April 2023

Most companies to date have adopted GHG emission targets in an effort to limit global warming well below 2 °C above pre-industrial levels, and 2020 estimations forecast a decrease of about 1/3 of emissions from O&G activities by 2050. It is also foreseen that regulations with economic impact on emissions from hydrocarbon production will be progressively adopted. This is triggering oil and gas (O&G) attention to find faster and economic ways to decarbonize while maintaining operational performance. Several types of initiatives are being considered including the reduction of flaring and venting, mitigation of methane leaks, increasing efficiency in energy use, use of renewable energy, and electrification of processes, in combination with the use of digital tools, and advanced monitoring to optimize performance.

In this work we focus on a comparison of different decarbonization pathways for an offshore platform. It is assumed that the platform is already in place and in operation, and that the industry is already taking the required actions to reduce flaring and venting and mitigating methane leaks. The analysis starts by identifying the major contributors to the GHG emissions from the platform, which in this case is the power system, followed by fluid related processes like compression, separation, heating for transportation, and other associated operations. Public data from international energy agencies indicates that approximately 16 TWh/year is used to power offshore oil and gas platforms globally. We analyze the following five decarbonization pathways: a) improved energy use - decreasing the energy demand of the processes running on the platform and associated operations, b) increasing the efficiency of the power generation source, c) changing the nature of power source (renewable – wind, solar, wave, hybrid systems), d) implementing carbon capture units, and e) electrifying the facility (partial/full electrification cases).

The analysis includes a comparison of promising concepts under each of the proposed pathways and summarize the challenges and opportunities offshore O&G operators have to implement them. Some of the alternatives are based on technology already used in the oil and gas industry, or in other industries, while in some others the technology is still under development. Reference is made to novel technology with potential to address the identified challenges for the different pathway options. We use a simplified metric system to highlight the most effective solutions according to location of the platform and its distance to shore. A discussion of what we will be needed for such pathways to be feasible is also presented.
Smart Wireless Data Transfer Solution for Underwater Sensors Powered by Edge Computing
Authors: Ignatius Manu , Anjangi Prasad , Chitre Mandar
Published: April 2023

With the ever-increasing number of underwater assets and structures driven by the energy industry's shift to renewables, the need for reliable long-term remote monitoring solutions for both environments and assets is growing. Such solutions typically consist of a suite of sensors, the data transfer mechanism, and data analytics and visualization. Underwater wireless technology is the key enabler for such a holistic monitoring solution that can be used for a variety of applications. However, many commercial operations are designed around the assumption that underwater wireless technology is not yet suitable for today's operational needs. While there are several advancements in the domain of underwater wireless systems in recent times, they have not made it to operational commercial systems. In this paper, we look at the example of Acoustic Doppler Current Profilers (ADCPs), where a typical operation relies on either offline data download or using a cable to perform real-time data transfer. We then illustrate how such an operation can be transformed by integrating a smart modem that packs technologies such as software-defined design, edge computing, and machine learning along with robust and reliable high-speed underwater wireless communications to an ADCP to achieve flexible and reliable wireless data transfer. The software-defined design aspect allows easy integration to a variety of sensors, in this example an ADCP. The edge computing and machine learning aspects allow the modems to optimize the data for a high-speed acoustic link that supports adaptive modulation and automatic retransmission to avoid data loss. Smart scheduling techniques are incorporated into the solution to support extremely low-power modes to enable long-term deployments. An application-specific web-based user interface (UI) provides a seamless user experience during the whole operation. Integrating such innovations to form a holistic solution for long-term monitoring can drive down overall costs and improve operational safety.
A Novel Hydraulics Design Approach Enables Simplified Configuration Offshore Wells
Authors: Sansoni Umberto , Waldmann Alex Tadeu De Almeida , Menezes Gabriela Marcia Ribeiro , Gonzaga Kaio , Suchodolak Daniel , Martins André Leibsohn
Published: April 2023

The reduction of the number of sections in the construction of an offshore well is a major driver for cost reduction. In order to achieve this goal, the sections must be longer, resulting in additional challenges. A critical aspect is related to the second section (no fluid return to surface) reaching high inclinations and longer extensions. Such sections are drilled with fluids with no carrying capacity, reaching 1500 m and inclinations as high as 65 degrees, resulting in expressive cuttings accumulation in the wellbore annulus. The scope of this article is to present a novel hydraulics design procedure which accounts for the effect of hole cleaning actions during well construction which reposition hydraulic parameters into acceptable criteria.

This paper details novel design procedures which include the following steps:

Defining cuttings bed height deposited along the wellbore annulus using traditional steady state cuttings transport models. This information is the initial condition for the design of hole cleaning pills pumping. Estimation of the extension of the cuttings bed through a material balance. Estimation of drag efforts for drillstring movement in the presence of a cuttings bed and the maximum well length which can be handled by the rig without carrying extra hole cleaning procedures. Calculation of the solids removal due to the pumping of hole cleaning pills based on a transient solid-liquid model. Optimization of the frequency, volumes and pump rates for the cleaning pills.

This way, the proposed methodology allows the creation of a hydraulics design package which incorporates the optimization of hole cleaning actions during the drilling of a deviated well with fluids which do not present cuttings carrying capacity. The procedure was successfully implemented in 4 offshore wells in Campos basin, offshore Brazil, which were built in only 3 sections including a horizontal section.

The present methodology is a milestone in hydraulics design for offshore wells, enabling the construction of horizontal wells in 3 phases resulting in a huge well construction time reduction.
Geological and Geotechnical Considerations for Floating Offshore Wind Infrastructure within the U.S. Atlantic OCS
Authors: Fisher James E , Esmailzadeh Saba , Fillingham Jacob N
Published: April 2023

Current offshore wind activities within the Atlantic Outer Continental Shelf are within water depths suitable for fixed-bottom foundations, generally considered as water depths shallower than 60 m. Recent BOEM designated call areas within the Central Atlantic include two areas on the continental slope in water depths greater than 200 m that will require floating offshore wind turbines. The objective of this study is to expand upon a previously completed BOEM-funded desktop study and focus on the geological and geotechnical conditions and the engineering constraints for the deep-water Central Atlantic call areas E and F.

This study focused on compiling public domain geophysical and geotechnical data to evaluate the seafloor and shallow subsurface geological and geotechnical conditions relevant to offshore wind within the area of interest. Data available from published scientific literature and government agencies were integrated and evaluated using GIS and seismic interpretation software to identify and map geohazards, seabed and subsurface conditions, and key stratigraphic geotechnical units.

Our evaluation of the area of interest indicates generally favorable conditions for floating offshore wind development, with site-specific considerations to be factored into engineering design. Soil provinces with similar geologic characteristics and geotechnical properties include the upper slope (roughly 200 m to 2000 m water depths) and the lower slope (greater than 2000 m water depth). General sediment conditions for both these provinces include Holocene-Pleistocene age silts and clays with intervals of sandy clay or sandy layers related to mass transport deposits (MTDs) from gravity flows. A key difference between the provinces is the potential for older geological units, such as the coastal plain deposits (CPD) within the foundation depth of interest proximal to the upper slope, and a higher frequency of submarine landslide deposits within the lower slope. The potential for slope instability and steep seabed gradients will be a constraint for these developments, as well as the potential for hard grounds, such as submarine landslide blocks or authigenic carbonate/benthic features. Based on these conditions, the suitability of various anchor concepts is discussed.
Comparison Between Molecular Sieves and Activated Alumina for Gas Dehydration in an Ultra-Deepwater Production Unit
Authors: Vieira Anderson Jalles de Meneses , Aimoli Cassiano Gomes , de Melo Dárley Carrijo
Published: April 2023

Activated alumina and molecular sieve performances are compared regarding key parameters such as adsorbed water load, outlet moisture content, pressure drop and adsorption capacity using different regeneration conditions. The comparison was done by operating one out of three vessels of a Brazilian pre-salt FPSO gas dehydration unit loaded with activated alumina, whereas the other two vessels were loaded with molecular sieves with a silica gel top layer.

During the early operation of the alumina, tests were performed by increasing adsorption time until the moisture breakthrough, conducted in two operational setups as follows: 1) a parallel-flow arrangement in which each vessel is loaded with one of the adsorbent materials, named dual bed phase; 2) a single stream flow to the vessel containing activated alumina, named single bed phase. Different regeneration temperatures were tested to verify the impact on the alumina capacity caused by low temperature regeneration. The results were compared to historical data collected using both type 4A and chabazite zeolites.

During preliminary capacity tests performed in laboratory and in pilot scale, the activated alumina delivered gas with moisture content generally between 1 and 10 ppm. However, during the industrial scale test reported here, the activated alumina was able to consistently deliver gas with moisture under 1 ppm after its first regeneration, operating both in single bed and dual bed arrangement. This result indicates that activated alumina was able to achieve gas specification once considered possible only by the use of molecular sieve. The initial dynamic capacity calculated for the alumina was comparable to the maximum dynamic capacities observed for the molecular sieves. In this test, the larger particle size of the activated alumina compared to the zeolites resulted in lower pressure drop through the alumina bed, culminating into an uneven flow distribution between both beds when in parallel-flow arrangement. Recommended regeneration temperatures are lower for alumina in comparison with the zeolites, resulting in lower energy consumption and associated CO2 emissions when using electrical heaters.

The novelty of this work lies in the use of activated alumina as the main adsorbent material in an ultra-deepwater gas dehydration unit with gas processing capacity over 6 MMSCMD achieving dry gas moisture as low as obtained by using molecular sieves. The use of activated alumina shows potential to improve efficiency and cost reduction that has yet to be confirmed by a longer test phase to check its stability and long-term performance.
Structure Health Monitoring for Tidal Blades Using Trustworthy Artificial Intelligence
Authors: Syed Muslim Jameel , Goggins Jamie
Published: April 2023

Our current reliance on fossil fuels is the primary contributor to global warming and threatens our survival. Renewable energy is currently considered the leading solution to reduce greenhouse gas emissions. Energy extraction from the ocean tides (tidal turbines) can help fulfill the global renewable energy demand and combat world climate crises. Installations at this scale will have the associated benefit of reducing the levelised cost of tidal energy (LCOE) towards a target of EUR100/MWh, which will make ocean energy a viable option along with other renewable energy sources such as offshore wind. To achieve the target, increased performance and reliability of tidal energy devices are required. Tidal blades are a primary component of tidal turbines, possess a heterogeneous nature and can suffer from complex non-linear damage modes. For example, harsh marine environments can cause impact damage, delamination, matrix crack, fiber breakage or rupture, and others in tidal blades, which could lead to catastrophic failure of the system. Achieving reliable operational health and performance for the tidal blade is thus crucial for tidal energy companies. Fault diagnoses and maintenance operations are challenging in the sea; performance degradation, failure, or breakdown of the entire tidal energy system are more likely if unattended. Therefore, there is the need for real-time and reliable structure health monitoring (SHM) of tidal blades. The existing damage detection techniques have a limitation when dealing with the real-time environment, and do not take into account the along with uncertainty feature, we also addressed the issue of trusthworthiness in system decision employed with explanable artificial intelligence (XAI). This paper presents a real-time damage detection framework, information communication technologies (ICT) based infrastructure for real-time monitoring and proposes a novel model to classify/ detect the damages over blade structure. In addition a XAI based approach is proposed which based on supervised machine learning (ML) and uses an optimized convolutional neural network to classify from the heterogeneous data streams. Testing and evaluation of proposed approach in laboratory and operational settings is the future concern of this study.
Integrity Management: A Basic Pilar of Efficiency Improvement Program for Offshore Production Unit
Authors: Ramis Marcelo Spessato , Langoni Arthur Machado , Pozzobon Felipe Barin , Risuenho Flavio Marcelo , Rego Fernando Cesar , Vitiello Rodrigo Pommerehn
Published: April 2023

The competitive scenario in the oil and gas industry nowadays requires an integrated and optimized management of resources to meet the needs of doing more, better, faster, with lower cost, ensuring operational safety and value generation for the business.

Mostly, efficiency maximization projects focus their actions on production, although we can observe that many bad actors are related to unexpected events such as accidents, leaks, material failures, etc. Therefore, to deal with efficiency maximization we must include safety, integrity, and legal compliance issues.

The construction of a sustainable efficiency project able to meet the requirements of society and to address all stated issues, should promote a cultural change, based on an active leadership enhanced by the use of technology.

In this sense, acting in the layer of "integrity management" is a fundamental pillar in maximizing efficiency and its process should promote the execution of actions in order to strive for the continuous evolution of management system.

Integrity management should go through all phases of the production unit´s life cycle, considering both the selection of materials and technologies - that must deal with all the changes that occurs in the operational conditions; as well as the effort required for its preservation/conservation, inspection and maintenance - which must be consistent with the manhour restrictions inherent to the offshore condition and with the issues related to maintenance service clearance for execution during the operational phase.

During this phase it is necessary to establish preventive mechanisms for the evaluation and detection of degradations, considering both structural and functional aspects, which may occur due to operational and environmental process conditions to which offshore production facilities are exposed.

In this context, quantification in terms of reliability for residual useful life is a tool that help the decision-making process, allowing companies to take the best actions considering the business market, as well as the current and future condition of the industrial plant.

This requires, among others, a specialized technical staff, a process with well-defined steps and records, and the establishment of a set of indicators that allows to demonstrate the actual situation of the installation and the perspective of evolution of its condition.

In order to encompass all the topics above, the EF100 efficiency improvement program was structured, consisting of 18 initiatives that have been contributed to consolidate a culture of integrity and reliability as a tool for generating business value. This article aims to explore the main actions defined for the improvement of the integrity management of offshore units.
Cost Reduction Challenges in Subsea Decommissioning Operations
Authors: Junior Fidelis José Coimbra , Bressan Robert Da Silva , Nicolosi Eduardo Ribeiro , Santana Andre Luiz Bervilaqua , De Souza Douglas Correa , Fernandes Paulo Tavares , Tavares Gabriel Maial
Published: April 2023

Decommissioning operations in Brazil are increasing with the end of life of several assets. A relevant challenge for the decommissioning scenario is the cost estimate for the operations due to the existent uncertainties found in the evaluated scenarios. The objective of the article is to present the work carried out through a strategic program to reduce the average decommissioning cost in subsea operations. The average cost reduction initiative involves a technical working group that includes subsea engineering, project management and subsea operations members. This initiative comprises four major areas. Three of them (pull-out, removal and subsea operations) cover new tools for operations and review of operational procedures, adapting them to the actual demands of decommissioning projects. The fourth area, technology, seeks to automate the development of the flexible pipe removal project, especially in offshore fields where several pipe crossings are present. Ten fronts are being implemented, such as building up pull-out alternatives, using new tools and procedures in addition to the conventional ones. On the Removal front, processes are being adjusted to reduce the amount of material needed and new flowline recovery techniques with the use of new tools are being tested and implemented. The creation of actions for mapping scraps on the seabed is also being carried out. Another front under development is focused on the implementation of new techniques for cutting flexible pipes, connection opening and plugging equipment. And finally, automation of the sequencing of flexible pipes and umbilical removal will bring a significant gain in terms of resources and time management, in addition to operational improvement. The expectation is that these multiple fronts will save about US$ 40 million during operations in the coming years, in addition to saving operation time and contributing to future operation. Furthermore, it is estimated a 48% reduction in total time compared to a standard operation, when we consider the accumulation of gains on each front. The novelty of this program is linked to the fronts dealing with technology and processes. The creation of a computational algorithm is proposed to design an optimal order of vessel interventions over a field, which is currently done manually by the project engineers.
Numerical Simulation of Subsea Wellhead Bearing Capacity in Deepwater with Novel Expandable Surface Conductor Foundation
Authors: Zhang Minghe , Yang Jin , Yin Qishuai , Song Yu , Wang Yuanming , Zhou Yisu , Li Lei , Yang Yuxiang
Published: April 2023

Subsea wellhead stability is an important technical issue in deepwater and ultra-deepwater oil and gas drilling operations. Since the soil under mudline is mainly silt and clay with weak cementation, the vertical friction force and horizontal displacement provided by the surface conductor are limited. The mechanical properties of subsea wellhead, including displacement and stress, are mainly distributed near the mud line.

The novel expandable surface conductor can effectively enhance the vertical bearing capacity and horizontal mechanical properties of the subsea wellhead by adding annular absorbent expansion materials to the conductor surface. In this paper, ABAQUS software was used to establish a numerical simulation model of the novel expandable surface conductor. Annular expansion material was installed on the upper, middle, and lower part of the surface conductor, respectively, to analyze its influence on the mechanical properties of the subsea wellhead. At the same time, the mechanical properties of the subsea wellhead of the conventional conductor and the novel expandable conductor are compared and analyzed.

The results show that the novel expandable surface conductor arranged near the mudline can effectively enhance the lateral mechanical properties of the subsea wellhead, but has little effect on the vertical bearing capacity of the wellhead, which is mainly due to the weak soil properties near the mudline. The annular expansion material in the middle and lower part of the conductor has little influence on the lateral mechanical properties of the subsea wellhead, but it is more obvious to improve the vertical bearing capacity of the wellhead, which is because the mechanical properties of the deep formation below the mudline are strong, and the horizontal displacement and bending moment of the conduit will not be transmitted to a greater depth under the mudline. At the same time, the lower end part of the expansion material has obvious influence on the vertical bearing capacity of subsea wellhead.

An exploratory study on the improvement of the mechanical properties of the subsea wellhead with the novel expandable surface conductor and basic rule is carried out through the numerical simulation method, which provides theoretical guidance for the subsequent industrial design and application of the novel expandable surface conductor.
Analysis of Wave-Driven Progressive Buildup of Excess Pore Water Pressure in Sands Supporting Marine Hydrokinetic Devices
Authors: Rafiei Amin , Gabr M. A. , Rahman M. S.
Published: April 2023

Instability of the seabed due to storm waves may cause damage to coastal/offshore structures. Saturated sand deposits in loose to medium dense condition contract under cyclic shearing causing the buildup of positive pore water pressure. For severe wave loadings, this could lead to a significant reduction of effective stress and soil liquefaction. In addition to detailed cyclic plasticity models for describing progressive generation of pore water pressure, a number of experimental models have been developed based on results of cyclic triaxial tests. Such tests mostly considered isotropic consolidation condition prior to cyclic shearing. However, the presence of static shear stress and hence anisotropy of geostatic stresses (e.g., under the foundation of structures) has been shown to alter the soil cyclic behavior significantly. Pan and Yang (2018) proposed a pore pressure buildup model for sands considering the effect of static shear stress ratio SSR on the residual response of the soil following anisotropic undrained cyclic triaxial tests. This study aims at modeling of wave-MHK-poro-elastoplastic seabed interaction with the focus on geomechanical investigation of pore pressure buildup in sands under various ranges of SSR.
Hyperbolic Soil Modeling - A Long Overdue Improvement in Soil Modeling
Authors: Verbeek Gerald E. , Bielefeld Marcel W. , Buitenhuis Rutger R.
Published: April 2023

Whether performing pile driving simulations or analyzing pile driving records, the weakest link in the computer model is the soil. Even though computing capabilities have expanded exponentially in recent years, soil modeling often still relies on the same equations when pile driving simulation programs were first developed in the last century. A typical example of this fact is the use of the elastic-plastic soil model and this paper aims to show that that model can and should be replaced by a more accurate hyperbolic soil model to incorporate nonlinear soil behavior.

The paper will reassess 4 cases where originally the elasto-plastic soil model was used (for both the pile driving simulation as well as the analysis of the pile driving records) by implementing a hyperbolic soil model. The outcomes for both models are then compared with each other and with the monitoring data during pile driving.
Asset Integrity Inspection with AI for Topside Offshore Structures & Marine Terminals
Authors: Zolfaghari Reza , Arif Usman , Gardenier John , Jolly Jordan , Alam Muhammad Hamza , Ferguson Eric Leonard , Castillo Marco
Published: April 2023

In this paper, we detail how damage mechanisms commonly found on marine terminal structures and process equipment can be automatically detected using a machine learning (ML) pipeline. Defects in its varied forms, such as corrosion, steel, wood and concrete damages must be closely monitored in offshore oil and gas platforms and also in marine terminals; the cost of not monitoring and detecting defects can range from unplanned shutdowns, plant damage, to human fatalities. On-site inspection of defects is labor intensive and require frequent travel to offshore and onshore facilities. This process has two shortcomings: firstly, it is costly involving man hours spent on the facility and secondly only a subset of the total defects is monitored during each inspection due to difficulty in obtaining full coverage; specially in this scenario a high-risk defect could be missed completely. We use marine terminals as an example of how defects can be detected using machine learning techniques, however the pipeline for generating the ML models could be extended to other types of defects and structures. Significantly, the output from our ML pipeline can be used as an input to the Risk Based Inspection (RBI) system assisting asset operators in their inspection and maintenance planning. Furthermore, digitized inspections and ML can provide around 95% coverage of the terminal while avoiding problems faced by a human inspector such as producing consistent results across inspections and sites.

Our system captured terrestrial spherical imagery and range data (LIDAR), subsea imagery, sonar, and ultrasonic thickness (UT) gauge data using different sensors and equipment on a marine terminal. Equipment used in our data-capture included an unmanned aerial vehicle (UAV), a terrestrial scanner, a remotely operated vehicle for underwater imaging (ROV) and a remotely operated surface vehicle (ROSV). For the purposes of this work, we used the images captured by the terrestrial scanner. We built an automated defect detection pipeline using state of the art machine learning and artificial intelligence (AI) tools taking the cube face images as inputs. The defect detection pipeline was trained with examples of defects labeled by asset integrity engineers to ensure quality of results. We built the pipeline to detect damage mechanisms for steel and wooden structures, however our system could be scaled to incorporate other types of defects and structures. Our AI pipeline was able to achieve a high level of accuracy identifying wood damage with a mean-Average Precision (m-AP) of 0.80 and steel damage with a m-AP of 0.84, where a m-AP of 1.0 indicates perfect detection of damage.
Labrador Gas – History and Opportunity
Authors: King Tony , Gillis Erin
Published: April 2023

Exploration in the 1970s and early 1980s identified approximately 4.2 TCF of natural gas and 123 million barrels of natural gas liquids on the Labrador Shelf within the Hopedale and Saglek basins. At the time, development was deemed unfeasible due to insufficient reserves and the threat posed by icebergs. Subsequent work has shown the original iceberg risk analysis to be very conservative. An iceberg risk model was developed to update the previous analysis and additional data was collected through a series of field programs. This resulted in a large multibeam mosaic covering the Makkovik Bank and pipeline landfall at Cape Harrison, and the development of a large iceberg scour database. An alternate landfall has also been identified at Cartwright with lower iceberg risk than the originally selected site.

In 2010, the Oil and Gas Corporation of Newfoundland and Labrador (OilCo) undertook a regional oil seep mapping and interpretation study covering all offshore Newfoundland and Labrador, to help identify areas of interest with active petroleum systems. Based on these results, from 2011 to 2020 Oilco acquired 2D and 3D long offset broadband seismic datasets targeting the Chidley Basin, in the slope and deepwater off Labrador. This data has been used to map and quantify potential hydrocarbon systems within the basin. In 2021, Beicip-Franlab conducted a resource assessment on behalf of OilCo, based on available geological and geophysical data from the Chidley Basin. As reported in "Offshore Newfoundland & Labrador Resource Assessment, Labrador South NL-CFB03", "results show the very likely occurrence of a working petroleum system in the Chidley Basin capable of efficiently generating and preserving liquid and gas hydrocarbons in the slope and deepwater basin". Hence, the probability of additional resources to increase the total reserves available to support a gas development is considered high. If exploration drilling confirms the presence of gas, then the total gas available for development will include the original 4.2 TCF and any new reserves. Hence, the two barriers originally identified to the development of Labrador gas (iceberg risk and gas reserves) may be resolved.
Effect of Shared Anchor System for a Floating Offshore Wind Project on Reductions in CO2 Emissions
Authors: Lee Junho , Aubeny Charles P
Published: April 2023

The trend of the offshore wind industry is expected to shift from fixed towers in shallow water to floating platforms in deeper water due to factors such as wind resource consistency and local seafloor bathymetry. The floating offshore wind industry requires cost-effective anchor alternatives suitable to a range of mooring types, water depths, geological locations, and environmental conditions. One attractive and cost-effective anchor solution can be the shared anchor system, with multiple mooring lines attached to a single anchor. Previous preliminary studies indicate that the shared anchor system provides significant capital cost savings due to its multiline potential resulting in reductions in required anchor footprints and logistic efforts. While they provide valuable insights into anchor performance and its cost-saving effect, these studies did not address the environmental impact in view of greenhouse gas emissions. This spurs the current study to estimate the effect of the shared anchor systems on reductions in CO2 emission. Firstly, this paper compares envisioned shared anchor systems, such as a suction anchor, a deeply embedded ring anchor (DERA), and a skirt, from optimal design standpoints. Secondly, embodied carbon in steel-based anchor alternatives is computed using a carbon calculator tool based on standardized data and compared to each solution. Lastly, the study carries out a comparative study on how anchor transportation from the factory to the construction site affects CO2 emission. The findings from the study provide a platform to select the shared anchor system considering cost reductions and estimate the environmental effects, which is a key consideration to Green Construction. The results show that the DERA is a cost-effective and environmental-friendly alternative for the floating offshore wind project.
A Comparison of the Increase in Capacity with Time for Normally and Overconsolidated Clays
Authors: Stevens Robert F.
Published: April 2023

This paper presents new findings not observed from the field blow counts alone for normally and overconsolidated clays. Refined analyses, including the Case Method and signal matching, show subtle differences in the driving behavior. Examples presented for normally consolidated clays are the driving of 30-in.(0.76-m)-diameter open-ended pipe piles, 14-in.(0.35-m)-square precast prestressed concrete piles, and 14HP73 H-piles. Examples are also presented for 48-in.(1.22-m)-diameter open-ended pipe piles driven in heavily overconsolidated clay. The shaft resistance and end bearing decrease with every hammer blow applied to the piles redriven in the normally consolidated clay profiles but were generally constant for the heavily overconsolidated clay profile. Set-up factors observed in the normally consolidated clay were 4.3 after a delay of 3.7 days for the 30-in.(0.76-m)-diameter pipe piles, and 3.3 after a delay of 4.7 days for the 14-in.(0.35-m)-square precast prestressed concrete piles. Set-up factors observed in the overconsolidated clay were 1.7 after a delay of one day, 1.8 after a delay of 5 days, 1.9 after a delay of 13 days, and 2.0 after a delay of about 15 days. The shaft resistance did not increase after a delay of one day but did increase for longer delays.
Droplet Size and Flow Characterization in Pipe Fittings and Valves (and Why People Keep Making the Same Mistakes)
Authors: Avila Carlos
Published: April 2023

Considerations on droplet size predictions and flow characterization when designing major capital projects and troubleshooting production operations can have a large impact on production system equipment from the wellhead to the oil export line. Areas benefiting from droplet size and flow characterization include improved prediction of flow assurance issues in flowlines such as hydrates and corrosion or separator sizing and interconnecting piping design. Simulations based on Computational Fluid Dynamics (CFD) simulations demonstrate how detailed fluid flow modeling in relatively small geometries can help to make better decisions on large-scale production systems. Characterizing the flow in flowlines, valves, fittings, and inlet piping to separators enables the prediction of the droplets carrying different phases and chemicals. A first group of CFD simulations characterizes the flow inside three different pipe fittings. A second group of CFD simulations compares the flow around the plate of a butterfly valve (and the immediate upstream and downstream pipe sections around the valve) at different openings. The use of refined mesh geometries to capture critical locations in each simulation and selection of proper turbulent models allows for proper calculation of the turbulent dissipation energy. Droplet size calculations were carried out once the turbulent dissipation energy driving the minimum and maximum droplet sizes was obtained. The simulations results include a comparison of previous work on flow characterization pipe fittings such as a long radius elbow, an impacting tee and a blind tee, and recent simulation results comparing the effect of different valve openings for a butterfly valve and their effect on velocities and turbulence and eventual impact on droplet size distribution. The effect on separation performance (quality of outlet streams) is significantly affected by inlet geometry choices (and resulting droplet size distributions) making the difference between a separator able to meet separation specifications or a design that will miss company expectations and regulatory requirements. Flow characterization and droplet size prediction can help the proper scale-up from experimental tests to large field applications. Simple solutions including smarter piping design upstream of separators and improved flow assurance assessments can have a large impact on improving overall production system efficiency and reliability. Development of improved guidelines that include the use of flow characterization will prevent repeating design mistakes.
Levels of Autonomation for VTOL Aircraft (LAVA): A Framework
Authors:   Boeing Co., Chen Ephraim , Befort Kendra , Brinker Joseph , Holthausen Brittany
Published: April 2023

The Levels of Autonomation for VTOL Aircraft (LAVA) framework is a mental model for measuring, specifying and evaluating degrees of automation for unmanned, optionally-manned and autonomic VTOL (vertical takeoff and landing) vehicles. The framework offers flexibility over many other approaches to provide tailored support of vertical flight applications by allowing the user to incorporate Level of Autonomation (LOA) elements as appropriate and formulate their own LOA scales, requirements and analyses. These elements are first outlined, using mission tasks and system functions to describe the total system behavior of operator and aircraft; overall automation ratings or detailed behavior allocations to express the degree of automation associated with the system behavior; and Technology Readiness Levels, Human Readiness Levels and Integration Readiness Levels to facilitate LOA risk assessments. Then notional examples are provided that illustrate employing LAVA to denote the LOA status of an existing system, develop LOA requirements for a new system design, and conduct an LOA technology and human integration readiness evaluation. Promoting LOA manifestations that address the balance of human attention and interaction with the automation is a central tenet of the LAVA framework, which brings methods and concepts such as Goal-Directed Task Analysis, Human-Autonomy System Oversight and Trust in Automation to bear on the human-machine allocation conundrum.