bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Ice Model Test Techniques and Services for Future Scenarios of Arctic Logistics and Infrastructure
Authors: Hisette Quentin , Reimer Nils , Schröder Christian , Myland Daniela
Published: April 2023

One consequence of climate change is that sea areas that were usually subjected to harsh ice conditions now become accessible for exploration of oil and gas and other offshore or shipping activities. The average ice extent decreases and the probability of heavy ice conditions decrease steadily in many arctic or subarctic regions. Nevertheless ice occurrence in those regions can never be excluded and extensive theoretical and experimental studies are usually performed to design and optimize floating platforms, coastal and grounded structures or other installations.

This paper discusses adaptions and prioritization in engineering approaches to address the needs of future scenarios of arctic maritime activities. Several crucial aspects to be considered when investigating the interaction of sea ice with a floating platform or vessel are reviewed and disussed through an exemplary operation case. The relevance of model tests is discussed with regards to model ice type, ice formation (level ice, broken ice, ice ridges, rubble ice, etc) as well as scaling of ice properties. In a first step the main gaps and uncertainties of state of the art scale model testing and numerical simulations in ice are identified. In a second step the list of open questions and uncertainties is compared to expected requiremnets of future arctic / antarctic activities.

A recently developed type of model ice specifically design for better reproduction of crushing failure is also introduced and compared to standard model ice. Furthermore, some complex testing methods such as the combination of wave and ice (marginal ice zone), the proper reproduction of friction (hull-ice, but also concrete-ice, rubber-ice, rubber-steel in port areas) as well as shallow water effects and modeling of ice impact to coastal structures.

In close relationship to the testing techniques, the instrumentation of the test set-up is of significant importance, since measuring accurate loads without affecting the quality of the modelling is not trivial. Most relevant/ suitable load measurement techniques (load cells, instrumented pockets, tactile sensors, etc.) are presented.

Additionally, the importance of simulation-based design is also discussed. Prior to a model test campaign, simulations can be used to compare several variants and select the most promising one(s) to be investigated further by model tests. Subsequently to testing, a simulation setup can be calibrated to extent numerically the matrix of experimental testing.
Offshore Wind Turbine in China: Overview, Research Trends, and Challenges
Authors: Li Chengxi , Singh Harpreet , Cheng Peng , Wang Xunjie , Hao Ge , Liu Qing
Published: April 2023

China's wind energy resources are abundant. Its exploitable wind energy reserves are about 1 billion kW(Burrows 2020). Among them, the offshore wind energy reserves that can be developed and utilized are about 750 million kW(Burrows 2020). Historically, the price of offshore wind turbines has been significantly high. However, its cost decline is accelerated due to significant technological advancements. Recently, offshore wind power can compete with China's coal and nuclear power in terms of cost. This study aims to provide a detailed review of the current status, research trends, and challenges of offshore wind turbine development in China.

Currently, the offshore wind turbine with the largest single-unit capacity released in China has reached 8 MW and will soon enter the 10 MW era. The most common offshore wind turbines in China are Gravity-based, Monopile, Jacket, and Tripods offshore wind turbines in shallow water, and SPAR buoy, Tension leg platforms, and semi-submersible in deep water. This paper first included an overview of these offshore wind turbines’ system functionalities, features, strengths, weaknesses, and case studies. We then focus on the critical technologies for developing offshore wind turbines in China. The current technology status of the major operators is also summarized, representing the most advanced technology on the market. At last, we briefly summarized the future research directions of offshore wind turbines.

In this study, we first gave an overview of offshore wind turbines currently on the Chinese market with several case studies. From these case studies, we recognized the critical technologies needed for the further development of offshore wind turbines. These technologies include hydraulic pitch technology, optimization design of the supporting structure for large-scale offshore wind turbines, offshore wind farm layout optimization, offshore power transmission, and intelligent operation and maintenance technologies. This study presented and analyzed these key technologies’ technical value, significance, development trends, and application scenarios.

This paper introduced offshore wind turbines and related case studies in various fields with different operational conditions in China. We extracted and summarized the critical knowledge and technologies from these case studies for current practices and future work, facilitating operators to understand and develop these technologies efficiently.
Vertical Exploration Approach for Seafloor Massive Sulfide Deposits
Authors: Wegerer Stefan , Semel Matthias , Weixler Leonhard
Published: April 2023

The transition towards renewable energy and the electrification of various industry sectors will undoubtedly lead to higher resource demand of our society. Metals like copper, cobalt or rare-earth metals are the basis of these new technologies. However, these elements are not yet available in sufficient quantities in our economic cycle. Hence, more material would be required to be extracted from open pit land mining. A suitable and promising alternative to land deposits are seabed mineral resources. The focus of this work is the development and analysis of a new method to explore seafloor massive sulfides (SMS) with regards to minimizing footprint of the operation in all aspects.

SMS reservoirs are mostly found in water depths between 2000m and 4000m. To explore these deposits in the deep sea a concept study based on a vertical trench cutting system has been developed. The extreme environmental conditions require mechanical calculations of the template stability on highly inclined slopes. Furthermore, the cutter tool performance and wear behavior are investigated on a test stand through cutting into rock probes, which have comparable mechanical properties as massive sulfides. The technical feasibility of the separation system was analyzed by computational fluid dynamic models simulating multiple-phase flow and its behavior.

For bulk sampling of massive sulfides two potential concepts were examined and compared against each other. The main difference is the conveying method of the sample material to the ocean surface. A discontinuous lifting system with a collector bucket has major advantages in contrast to a riser system. During short exploration campaigns substantial energy and cost savings were estimated for a mechanical intermittent ore transportation. The first results regarding the effectiveness of the separation container could be demonstrated. The separation process takes place in a large scale hydrocyclone in-situ on the seafloor. The ground stability for the landing and leveling of the deep sea sampling unit was verified.

Key aspect of the vertical trench cutting approach is the minimal environmental impact during the whole exploration phase. At the same time this system enables to retrieve large amounts of sample material in an economical way.
A Macro-Scale Generalized Search and Rescue (SAR) Model for the Coastal Regions of Eastern Canada and the Arctic
Authors: Zarrin Mehr Mohammad , Molyneux David , Smith Jennifer , Pelot Ronald , Goerlandt Floris , Brown Robert
Published: April 2023

Given the complexity of Search and Rescue (SAR) activities in the coastal regions of Eastern Canada and the Arctic, there is a need to objectively assess system capabilities at a high level to determine the expected rescue time for multiple scenarios and system configurations. This paper outlines a new macro-scale generalized SAR model to simulate the main activities within the SAR system in Eastern Canada and the Arctic. The model uses discrete event simulation to represent the SAR operations and a probabilistic Monte Carlo approach to incorporate uncertainties in performance data for the different components of the system. Algorithms are first developed to identify the major decision-relevant components of SAR response, including the time to interpret emergency notifications and mobilize helicopter resources, the operability of assets in given environmental conditions, and the proximity and capability of resources. Following this, the model is coded in MATLAB, using a time-stepping approach, enabling changes in the scenario, asset status, and system configuration at any time step. Case scenarios are used as initial verification, beginning with a simplistic approach, and building complexity in the model parameters.

For this paper, we will discuss simple and complex scenarios which are based on common incident occurrences and SAR system operational details in eastern Canada's coastal regions and the Arctic. We assess the sensitivity of the overall SAR system to various input parameters to better understand how factors such as the Location of Incident (LOI) and number of People in Distress (PID) influence SAR response time in remote coastal areas, as well as the impact of refueling station locations for more distant and longer duration scenarios.
Introduction of Azipod DI and ESS for Icebreakers
Authors: Hanninen Samuli , Hakala Jani , Viherialehto Sampo , Maattanen Pirjo , Heideman Torsten
Published: April 2023

Polar multi-year ice thickness and extent will continue to reduce, and the traffic volumes in polar seas are expected to grow. Since the first podded propulsion was installed in an icebreaking vessel more than 30 years ago, Double Acting ships have delivered excellent results, revolutionizing the design and operations of icebreaking vessels. After that a completely new fleet of Double Acting tankers and icebreaking support vessels have successfully proven their abilities. The same development has enabled even larger and more capable ice vessels. Podded propulsion is an attractive solution, making these innovative icebreaking ship concepts technically and commercially feasible.

The Finnish icebreaker Polaris is one of the most advanced ships in its class. Innovative designs were used for the vessel's hull form and propulsion unit arrangement. The vessel can use either liquefied natural gas (LNG) or low Sulphur diesel oil as fuel. The propulsion system of IB Polaris is based on Azipod® propulsion and it applies a novel three propulsion unit concept. Recently, ABB conducted a study to show how an Energy Storage System (ESS) could help improve the overall power efficiency of icebreakers, saving fuel and reducing emissions. In this case study, a real ice operation data and powerplant load profile from icebreaker Polaris was used to simulate the effects of adding an ESS. The simulation indicated substantial benefits to both LNG and diesel operation. The key findings of the study will be presented in this paper.
Detection and Assessment of Asphaltene Precipitation/Deposition at Reservoir Conditions and Gas Hydrate Formation in the Presence of Thermodynamic Hydrate Inhibitors
Authors: Delgado-Linares Jose G. , Wang Weiping , Ayyad Wedyan , Majid Ahmad A. A. , Pohl Mathias , Yoda Chitose , Tanaka Norio , Zerpa Luis E. , Prasad Manika , Koh Carolyn A.
Published: April 2023

The occurrence of asphaltenes and gas hydrates represents a serious flow assurance problem faced by engineers at different stages of oil production. Early detection and evaluation of the impact of these solids on the hydrocarbon flowability is key in reducing the OPEX for remediation treatments. The access to reliable experimental data on asphaltene and gas hydrate formation and mitigation at reservoir/field conditions represents a valuable tool to improve the accuracy of existing prediction models / software packages and make them applicable for new scenarios faced by the industry. In this work, asphaltene precipitation/deposition and redissolution in a core was detected by using in-situ acoustic measurements at ambient and high CO2 pressures. Acoustic velocity increased during asphaltene deposition, indicating a cementing effect in the sample pores. In contrast, asphaltene redissolution with toluene induced a reduction in velocity of the acoustic wave travelling through the sample.

Rheological properties, such as viscosity and yield stress, were measured for hydrate slurries in crude oil for under-inhibited systems with two different thermodynamic hydrate inhibitors (THI): methanol (10 vol.%) and monoethylene glycol (10 vol.%). The addition of these thermodynamic hydrate inhibitors reduced the amount of formed hydrates with respect to the untreated system, and thus the viscosity and yield stress were also reduced.
Pipeline Fatigue Damage Monitoring During Hydrogen Transportation
Authors: Bhowmik Subrata , Sun Ta Ju
Published: April 2023

Real-time monitoring of the existing natural gas infrastructure using multiple sensors is crucial to achieving higher confidence and lower risk during hydrogen transportation. One of the main challenges during hydrogen transportation is that hydrogen can accelerate the pipe material's fatigue crack growth rate, which can be affected by operational variables like hydrogen gas pressure, load ratio, and load cycle frequency. The proposed solution will involve the development of a digital twin framework incorporating a data-driven fatigue crack model of existing natural gas pipelines. The digital twin system comprises three main components. A computational finite element-based model of the crack defect in the pipe is developed to calculate the stress intensity factor (SIF) for different crack lengths and depths. The computation model is used to estimate the fatigue damage. The input and output data from the computational model are used to develop a metamodel or surrogate model. The metamodel is a data-driven model typically used to replace the computational FE model in real-time fatigue damage monitoring or to estimate the remaining fatigue life. The data-driven and computational model outputs the fatigue damage or remaining fatigue life, which is an essential part of the decision-making process in the digital twin framework.

Machine learning-based algorithms: Extreme Gradient Boosting (XGBoost) is used to estimate the SIF through a surrogate model. The result from surrogate model is compared with the Physics-based/ simulation model. This work uses Paris's law in the crack propagation model to calculate the fatigue crack's growth rate. Conventional S-N curve methods can only provide information about fatigue life, which typically corresponds to the point of fatigue damage initiation. In a digital twin system, the crack model predicts the crack growth or damage propagation which is a substantial advantage for real-time pipeline integrity management during hydrogen transportation.

The proposed concept will provide a predictive early identification methodology for possible hazardous conditions specific to natural gas pipelines for hydrogen transportation.
Vito FPS: Designing a Simple, Light-Weight, Single Lift Topsides
Authors: Cabrera Jonathan Evan , Bradford Graham Patrick , Lewthwaite Ralph Stephen
Published: April 2023

This paper provides an overview of the design of the Vito topsides production train and the overall approach to achieve a minimum technical scope, a simplistic design, and limit the payload to 10,000 st. A 10,000 st topsides target was utilized in order to fabricate a single topsides module and integrate the deck with the hull in a single lift, which were key enablers to maximize flexibility and efficiency in construction and commissioning. Efforts to design the topsides production train included focusing on an integrated approach with the wells and flow assurance teams to optimize the end-to-end design and enable the elimination of unnecessary topsides equipment, thereby reducing the total topsides footprint and weight. The topsides design focused on an "industry solution," by partnering with industry firms to evaluate the minimal equipment required to meet the nameplate capacity of 100,000 bopd. Redundant equipment, whose function could be accommodated via other equipment, was eliminated and the production train was optimized as an overall system, rather than focusing on individual equipment design.

Key challenges included reducing the overall weight of the original Vito concept by 75% through rigorous evaluations of what the "minimal scope" should include. This was achieved through setting aggressive targets, actively managing design and scope growth to meet the targeted lift weight, designing and operating a facility that "looks different," balancing expected availability of the facility with weight and cost trade-offs, limiting future expandability, and reducing Personnel Onboard (POB).

The end result was a radical redesign of the Vito Floating Production System (FPS) with simplified equipment and systems designed against minimum technical specifications, resulting in a weight reduction of the host by ~75% allowing for a much more efficient use of Company's CAPEX (Capital Expenditure) and an industry competitive FPS (Floating Production System).

This paper is part of a Vito Project series at OTC 2023, and the other papers are listed in the references.
The Importance of Secondary Traps and Sinks in Offshore CO2 Sequestration
Authors: Coffin Richard , Vasilyeva Maria , Pecher Ingo , McConnell Dan
Published: April 2023

Geologic carbon sequestration currently focuses on injection of supercritical CO2 into reservoirs, often in a depleted hydrocarbon field. Seal integrity above these reservoirs is therefore critical for safe long-term storage of CO2. It is generally assumed that if a reservoir was able to contain hydrocarbons for millions of years, it should be suitable for CO2 storage. However, many hydrocarbon reservoirs leak, probably best documented by the ubiquitous natural gas and oil seeps observed e.g., in the Gulf of Mexico. With integration of seismic and geochemical data and fate-transport modeling there is capability to select efficient storage locations in the deep coastal sediment and provide accurate assessment of CO2 residence time.

We propose that even if reservoirs leak CO2, abiotic and biogeochemical reactions from the injection point to the ocean floor surface provide diverse traps that result in efficient sediment CO2 sequestration. First, during the migration concentration in porewater becoming supersaturated can result in a carbonate formation. This carbonate formation may cause a trap and with the CO2 build up there can be pressurization that results in horizontal migration to a new vertical path or pressurization that results in fractures of carbonate or clay layers. This transport can occur at multiple intervals during migration to the surface sediment and this step-by-step trapping slows down long-term vertical migration.
Johan Sverdrup: The Final Lap of a True North Sea Giant
Authors: Lossius Vibeke , Nedrelid Tone
Published: April 2023

The second phase of Johan Sverdrup came on stream in December 2022. This paper focuses on the execution of Johan Sverdrup phase 2 and describes the assessments and investments for improved oil recovery (IOR) from one of the largest oil fields in Norway.

The Johan Sverdrup field development has been called Equinor's ‘digital flagship’, and this paper includes the proof of concept for the digital initiatives after more than three years of operation.

Despite the Covid-19 pandemic Johan Sverdrup phase 2 has been able to deliver on schedule, under budget, and with an excellent safety record. The paper includes experiences from the concept development and engineering phase to the global contracting strategy, through the construction on multiple building sites in Norway and globally, and until the end of the completion phase offshore Norway.

Johan Sverdrup is the third largest oil field on the Norwegian Continental Shelf (NCS), and with recoverable reserves estimated at 2.7 billion barrels of oil equivalents, has the resources to be a North Sea Giant. Start-up of the Johan Sverdrup phase 2 extends and accelerates oil and gas production from the NCS for another five decades. This paper aims to highlight what it took to make Johan Sverdrup a true North Sea Giant, fit for the 21st century: a safe and successful execution of a mega-project, with next-generation facilities adapted to a more digital way of working, with an ambition to profitably recover more than 70% of the resources, while limiting carbon emissions from production to a minimum. In many ways the Johan Sverdrup development has set a new standard for project execution in Equinor.

The impact of different variables made during the execution of the project, such as the Covid-19 pandemic, market effects, procurement strategies, value improvement initiatives, execution performance and reservoir characteristics is addressed, as well as describing assessments and investments for improved oil recovery (IOR). Data acquisition, Permanent Reservoir Monitoring (PRM), fibre-optic monitoring of wells, innovative technologies, and digitalization, as well as new ways of working are included. Equinor´s digital strategy was established in 2017, and Johan Sverdrup was highlighted as a digital flagship at that time and a frontrunner in applying digital solutions to improve safety and efficiency from the development to the operational phase. What has been implemented so far together with experiences will be shared.
Selection of An Optimum CO2 Dehydration Technology: A Case Study Comparing Absorption and Adsorption Technologies
Authors: Müller Dieter , Greene Margaret , Pan Justin , Thompson Kirstie , Deshmukh Salim , Grison Arnaud
Published: April 2023

Carbon capture and storage (CCS) projects are increasingly being announced as companies strive to reach new sustainability targets. The dehydration of CO2 streams from carbon capture is a critical step to ensure safe and effective CO2 transport and storage. The most common dehydration methods are Triethylene Glycol (TEG) absorption and solid material adsorption. Silica gel, activated alumina, and molecular sieves are different types of adsorbent materials that can be used for gas dehydration. In this paper, the authors present a case study requiring a <100 ppmv H2O outlet specification and evaluate the technologies on capital and operational costs.

There are factors beyond treated gas water specification to consider when choosing the ideal dehydration solution, including treated gas glycol specification, plot space, module weight, maintenance intensity, energy duty, and start-up time. When these factors are considered, aluminosilicate gel adsorption technology has benefits over TEG. No one factor can be used to make the decision on which dehydration solution is best; those factors holding more weight depend on the specifics of a given project.
Arctic Field Testing – Developing the Next Generation Passive Fire Protection
Authors: Skilbred Anders W. B. , Wierzba Zuzanna , Irving James
Published: April 2023

Epoxy passive fire protection (PFP) products are extensively used for fire proofing of structures and assets around the world. Significant projects such as construction of large hydrocarbon processing industry (HPI) plants may require a global supply chain meaning that a structure or an assembly may be manufactured one location and assembled in another. Manufacturing, application of coatings, handling, transportation, and construction will for many large projects take place in different climates. It is therefore important that an epoxy PFP product shows excellent cold climate properties for all climate performance.

This study presents mechanical properties of one newly developed and three commercially available epoxy PFP products. The flexural strain of the newly developed epoxy PFP was found to be similar or higher than the other tested products for temperatures between −50 °C and 20 °C. Further, the strength at break, i.e. at the point of fracture, of the tested epoxy PFP products was found to increase as a function of decreasing temperature. Leading to the conclusion that the newly developed epoxy PFP was more robust at especially at lower temperatures, compared to the commercially available products.

An Arctic test station located outside Longyearbyen at Svalbard in Norway was used for outdoor cold climate exposure After approximately one year, it was found that a low flexibility product showed significant cracking, whereas the more robust newly developed epoxy PFP showed no visual degradation.
Thermal Insight - Digital Twin Technology for Enhancing Asset Uptime and System Reliability
Authors: Målbakken Kristian , Sundell Emma , Martinsson Andreas , Vullum-Bruer Kenneth
Published: April 2023

Thermal Insight, visualized in Figure 1, establishes a new frontier for operators to increase reliability and uptime of SPS systems by avoiding cold restarts. The Digital Twin is a live diagnosis tool that provides critical information about the actual cool down time of critical locations in the Subsea Production System (SPS), in the event of an unplanned shut down.

Based on verified Computational Fluid Dynamics (CFD) tools, Thermal Insight adopts a holistic full field view and feeds back the actual cool down time in predetermined stringent locations to the operator. This facilitates well informed decision making, opposed to immediate shut down and cold restart following conservative cool down requirements and philosophies.

The inner workings of the Digital Twin are a Reduced Order Model (ROM) set of differential equations based on a-priori CFD simulations which reveals the cool down time in critical locations, and not only in the location of installed hardware (PTT sensors). The CFD results are used to correlate the real time temperature readings from the Pressure/Temperature Transducer (PTT) to cool down times in the most stringent parts of the SPS, limiting the number of cold restarts to when it is really needed.

This paper will outline the CFD model verification work along with the Digital Twin deployed onto an example scenario based on actual field data from an operator.
Subsea Inspections with New Models of Autonomous Underwater Vehicle (AUV): Deployment Modes, Advantages and Disadvantages
Authors: Britto Antonio J.P.R.
Published: April 2023

The proposed paper aims to present an analysis considering the use of new technologies of Autonomous Underwater Vehicle (AUV), considering its use to carry out subsea inspections on Subsea Production System (SPS), addressing possible launch and recovery methods, listing advantages and disadvantages of using this technology.

The analysis is based on evaluation of new developments of AUV, considering that it will present hovering capabilities, like what is presented by typical Remotely Operated Vehicle (ROV), and additional functionalities that will improve the integrity management of the SPS. In this context, there is a range of possibilities for the use of these new technologies of AUV. The main scenarios of use will be detailed, as well as its advantages and disadvantages characterized.

By analyzing the main possibilities of using new technologies of AUV, as well as the advantages and disadvantages of using it, will be possible to state that there is a plenty room to significantly improve the integrity management of the SPS. The way that these new models of AUV can be applied will enable the Oil and Gas industry to achieve a higher level of integrity management of the SPS, also having a significant reduction on Operational Cost (OPEX), increase of personnel safety and reducing of greenhouse gas emissions.
Multiphase Flowmeter Comparison in Complex Field
Authors: Alqahtani Mohammed , Baghdadi Faical , Wenrong Mei
Published: April 2023

Well testing is one of the most vital data obtained, which provides numerous information that is related to the well's performance. It is also important to acquire an accurate rate test for reliable allocation and production planning. This paper's objective is to analyze and compare the accuracy of two different types of multiphase flowmeter (MPFM) against a conventional portable test separator. These two types of MPFMs are from two different vendors and each has its own mechanism.

A portable testing campaign was initiated with the intention of comparing the MPFMs’ phase rates against those of the separator. The portable testing unit (PTU) was connected downstream to the MPFMs, which were visited pre-campaign by their respective vendors and the required calibration was conducted.

A total of 41 wells from various reservoirs and production conditions was evaluated with multirate tests. Overall, the results showed a considerable difference between the phase rates of the traditional test separator and those of the MPFMs regardless of the type where both MPFMs did not meet the minimum requirement of having an acceptable error percentage and only nearly 50% of the tests were within an error range of 10%. One MPFM marginally outperformed the accuracy of the other one.

Two problematic regions with high discrepancy between the two metering types were identified either under low-liquid rates or high gas-volume fraction (GVF). Some identified causes will be discussed, which can be of high use by operators who are willing to conduct such comparisons.
Boosting To Boosting: A New Approach To Enhance, Support And Maximize Subsea Processing And Boosting Applications
Authors: Roberto Marcello Augustus Ramos , E Silva Jean Carlos Dias , Koelln Herbert Prince , Bernardes Alan Carlos , Albuquerque Fabio Alves , Paternost Guilherme Miranda , De Oliveira Ana Margarida , Xavier Gilberto Magalhães , Da Silva Jurandir Antônio Gomes , Da Costa Otavio Cardoso
Published: April 2023

Over the last 20 years subsea processing and boosting (P&B) technologies have supported and pushed forward the offshore oil and gas production, maximizing field production and recovery factor. Although those technologies achieved remarkable success, P&B is still not a heavy-weight business, despite Operators considering it adds great value. Therefore, to enhance and maximize P&B applications, a task force was created to identify the main hurdles, showstoppers and barriers, as well as to establish a robust process, methods and procedures related, including O&G Operators and Suppliers point of views, internal standards and international codes analysis.

Afterwards, a critical analysis was made, more than ten initiatives were prioritized, and a Program named Bosting to Boosting (B2B) was structured.

This paper will present all initiatives have been carried out in B2B and the main results for subsea projects.
Credibility Assessment of Annular Casing Cement for P&A Campaigns: A Case Study in Campos Basin Offshore Brazil
Authors: Moreira Rafael Peralta , Piedade Thiago da Silva , De Matos Marcelo Victor Tomaz
Published: April 2023

The assessment of annulus cement barriers is critical in well Plug and Abandonment (P&A) planning and execution. For wells with 10 to 30+ producing years, the data from well construction may be unavailable, incomplete, or not fully compliant with current industry good cementing practices. This case study presents a methodology for assessing qualification and credibility of annular hydraulic isolation, highlighting the challenges involved in the process.

The engineering workflow starts by data mining from well construction regarding casing and cementing operations, drilling fluids, pumping schedule, wiper plugs events, casing centralization, washer, spacer, and cement slurry design in addition to anomalous events occurred. A mapping of the cement quality is then performed in representative wells which have availability of data with uniform criteria to establish key performance metrics. Finally, a novel statistical imputation methodology is then performed to overcome missing data followed by modeling and simulations, and a credibility analysis resulting in the qualification degree of the annulus cement – qualified permanent barrier, unqualified or failed.

The methodology was applied for subsea wells in P&A campaigns in Campos Basin offshore Brazil, by using this credibility & criticality assessment in the B-annulus hydraulic isolation as an input for the P&A design and resulted in increased applicability of Through Tubing scope - without the necessity to remove the production tubing – and eliminated the need of additional evaluation of the production casing cement through logging tools or pressure testing. Consequently, a 5-day average reduction in P&A intervention was obtained. The analysis showed that the cementing strategies performed in well construction dates, despite different from current practices, provide sufficient cement quality in many scenarios. The studies conducted also show the correlation between cement evaluation logs and modeling of existing cement jobs with data imputation techniques to compensate for missing data in cement-job data.

New methodologies and technologies for the assessment of annular isolation in wells to be plugged and abandoned are of relevant interest for the industry and taking in consideration the uncertainties and field experience into the qualification process of existing barriers is a challenge. This paper provides insight on how uncertainty levels may be reduced to still provide quantitative results and allow the selection of an optimized P&A design.
Utilizing Real-Time Downhole Data for Optimizing Completions in Tight Margin Deep Water Wells
Authors: Hawthorn Andy , Groves Duncan , Broussard Grant
Published: April 2023

Infrastructure costs in the deep-water environment are expensive. There is therefore, both from a cost perspective, but also increasingly from an environmental perspective, an increased drive toward deriving more production from existing infrastructure. One example of this is going after additional reservoirs from the same platforms that may have initially been bypassed. This includes reservoirs that may have been technically challenging, or at the time considered uncompletable. To constrain uncertaintites in pre well construction models requiresrequire good data, from the right place, at the right time. Up until recently during well completion operations this has not been available in real-time from downhole. If we look at the world of drilling, then this has been revolutionized in the last 30 years by access to real-time downhole data. Far more complex wells are drilled, in increasingly complicated downhole conditions and geosteered through the reservoir sections utilizing real-time downhole data. Almost all other well construction activities have, to a certain extent, been operated using only surface data and models about what is happening downhole.

In this paper we will look at technology that has been recently introduced that allows access to real-time downhole data by transmitting acoustic signals through the wall of regular drillpipe. This means that downhole and along string measurements of pressures, temperatures, weights and torque are now available to aid in decision making and to drive the efficiency of operations. This data driven approach to well completions will show through real examples how an operator moved from wells that were once considered uncompleteable, through initially stand-alone screens and then onto gravel packing the same reservoirs. Thereby improving both the initial production rates and delaying the time to intervention.

This paper will further show how a gradual implementation of technology across a sequence of wells allowed for wellsite and onshore personnel to become familiar with and understand the limitations, and or benefits, of combining various technologies to meet the demands of the field. Technology implementation has often failed due to ingrained processes and personnel unfamiliar with the technology continuing to operate in the same way as previous. The technology is very important but we should not neglect the difficulties of implementing technology and allowing people to accept it's use.
Damaged Control Line Solution to Sustain Functional Downhole Safety Valve and Avoid Completions Recovery
Authors: Negi Rohit Singh , Maclurg Michael John , Russell Nicholas Draper , George Joel Bejoy
Published: April 2023

An Oil & Gas company experienced an issue with communication to the Sub surface safety valve (SSSV). To address this issue, a unique solution was developed to avoid the need for a workover and restored surface communication with the SSSV.

One of the offshore wells in United Arab Emirates developed a blockage in the Control Line (CL), leading to an inoperational SSSV. As a result, it became necessary to close the well. This situation would normally continue until a completion workover could be scheduled.

An alternative solution was implemented in this well and restored production through the SSSV without the need to perform a workover.

After collecting data such as wellhead details, SSSV profile, and production history, a custom Safety Valve communication system was designed and installed. The Lower Master Valve was modified to allow an in-tubing control-line communication, which in turn located the retrofit SSSV. The old CL was also isolated as part of this operation.

Over two stages of operation, the wellhead modification was performed and the installation of a replacement surface controlled SSSV, wet connect, CL, and CL hanger was completed. The system was then tested successfully prior to handing the well back to production.

The installation of this system saved the cost of rig mobilization and completion recovery as a barge was utilized to install this system as opposed to a workover rig with all the associated additional resource and costs. Supported by flow modeling prior to design and installation, the installed system maintains its integrity while the well is producing at normally expected flow rates. This is a retrofit solution that can be engineered to suit any well with various combination of wellheads and downhole completion accessories. The system follows oilfield standards as required for a safety-valve barrier. It can be used to extend the production duration of the mature wells before an expensive workover operation becomes necessary. The type of wellhead penetration used does not affect the functionality of the existing wellhead valves.

Installation of this system saved the cost for a workover rig, replacement completion equipment, and brought a previously shut-in well into production. This system provides a significantly safer alternative compared to the restrictive storm-choke devices and ultimately brings the well back online, while adhering to industry standard definitions for surface-controlled SSSVs.
Key Takeaways from Integrated Production Modelling of an Indian Offshore Field Entirely Operating On Electric Submersible Pumps
Authors: Devshali Sagun , Nischal Rajiv , Prasad BVRV , Yadav M , Vamsi Paipuri , Uniyal Rishabh , Kumar Manish
Published: April 2023

Field Alpha is situated about 200 km West of Mumbai city in a Deep Continental Shelf at the water depth of 85 - 90 m. The existing facilities consists of 5 Well Head Platforms (WHP) connected to FPSO through a subsea PLEM and riser system. A total of 36 wells from 5 well head platforms in the field are producing 61348 blpd with an average water cut of 68%. All these 36 wells are producing through Electric Submersible Pump which is one of the most effective and economical means of lifting large volumes of liquid. The current paper is an attempt to address various issues pertaining to Electrical Submersible Pumps in the offshore field using well wise Nodal Analysis and Integrated Production Modelling.

In the field under study, as the production volumes per well are high, failure of even one ESP leads to substantial production loss till the system is replaced by work over operation. Failure in the ESP system generally occurs due to one or a combination of issues related to reservoir inflow, fluid properties, design, completion, electrical components and experience of manpower. On the basis of system analysis, requisite optimization/ intervention measures proposed to improve performance of ESPs along with network debottlenecking results have been discussed in the paper.

As per the analysis, scope exists in 7 wells for production enhancement. The envisaged incremental production from these wells has been found to be 1653 blpd considering current reservoir pressure and water cut. In 7 wells, ESPs have been found to be operating either in upthrust or are tending towards upthrust. These wells have potential to produce more but due to limitations of the existing pump capacities, the maximum drawdown is restricted. In 6 wells, ESPs have been found to be operating in downthrust. These wells have separately been assessed for wellbore performance.

Additionally, Integrated Production Modelling indicated that the node pressure at each Well Head Platform are within the ESP design pressure limits. On the basis of the study, few of the recommended measures have already been implemented in the field and have resulted in a liquid gain of 335 blpd (139 bopd).
The Role of Professional Societies to Build a More Inclusive Energy Sector
Authors: Zarate Luz
Published: April 2023

To this day, the energy sector is still male-dominated. Based on the data collected as part of the Organisation for Economic Co-operation and Development (OECD) LinkEED project, in some regions, the gender gap is twice as large as that seen in non-energy sectors; wages perceived by women can be about 20% below men (taking into consideration factors such as education and experience) and the wage gap increases with age for the energy sector and is higher for high-skilled professionals. As a result, women are more likely to leave the energy sector – at all ages. The energy sector is changing as we transition to clean energies. Policymakers are promoting benefits around childcare and eldercare that could encourage more women to remain in the workforce, yet there is much work to do. Professional societies play a crucial role in providing women with opportunities to grow their careers – from outreach to networking opportunities for experienced professionals – the mechanism to provide a support system is there. In this paper, we will discuss the work that the Society for Underwater Technology (US branch, SUT-US) is doing to champion, retain and promote women in energy through its Women in Industry task force (SUT-WiND). For SUT-WiND, it has been clear that having men in the conversation is imperative to achieve more remarkable progress toward inclusivity. Through a series of quarterly events on thought-provocking topics.
CD4 Effector TCR Avidity for Peptide on APC Determines the Level of Memory Generated
Authors: Jones Michael C , Castonguay Catherine , Nanaware Padma P , Weaver Grant C , Stadinski Brian , Kugler-Umana Olivia A , Huseby Eric S , Stern Lawrence J , McKinstry Karl Kai , Strutt Tara M , Devarajan Priyadharshini , Swain Susan L
Published: April 2023

Initial TCR affinity for peptide Ag is known to impact the generation of memory; however, its contributions later, when effectors must again recognize Ag at 5–8 d postinfection to become memory, is unclear. We examined whether the effector TCR affinity for peptide at this “effector checkpoint” dictates the extent of memory and degree of protection against rechallenge. We made an influenza A virus nucleoprotein (NP)-specific TCR transgenic mouse strain, FluNP, and generated NP-peptide variants that are presented by MHC class II to bind to the FluNP TCR over a broad range of avidity. To evaluate the impact of avidity in vivo, we primed naive donor FluNP in influenza A virus–infected host mice, purified donor effectors at the checkpoint, and cotransferred them with the range of peptides pulsed on activated APCs into second uninfected hosts. Higher-avidity peptides yielded higher numbers of FluNP memory cells in spleen and most dramatically in lung and draining lymph nodes and induced better protection against lethal influenza infection. Avidity determined memory cell number, not cytokine profile, and already impacted donor cell number within several days of transfer. We previously found that autocrine IL-2 production at the checkpoint prevents default effector apoptosis and supports memory formation. Here, we find that peptide avidity determines the level of IL-2 produced by these effectors and that IL-2Rα expression by the APCs enhances memory formation, suggesting that transpresentation of IL-2 by APCs further amplifies IL-2 availability. Secondary memory generation was also avidity dependent. We propose that this regulatory pathway selects CD4 effectors of highest affinity to progress to memory.
Human CCR6+ Th Cells Show Both an Extended Stable Gradient of Th17 Activity and Imprinted Plasticity
Authors: Singh Satya P , Parween Farhat , Edara Nithin , Zhang Hongwei H , Chen Jinguo , Otaizo-Carrasquero Francisco , Cheng Debby , Oppenheim Nicole A , Ransier Amy , Zhu Wenjun , Shamsaddini Amirhossein , Gardina Paul J , Darko Samuel W , Singh Tej Pratap , Douek Daniel C , Myers Timothy G , Farber Joshua M
Published: April 2023

Th17 cells have been investigated in mice primarily for their contributions to autoimmune diseases. However, the pathways of differentiation of Th17 and related Th cells (type 17 cells) and the structure of the type 17 memory population in humans are not well understood; such understanding is critical for manipulating these cells in vivo. By exploiting differences in levels of surface CCR6, we found that human type 17 memory cells, including individual T cell clonotypes, form an elongated continuum of type 17 character along which cells can be driven by increasing RORγt. This continuum includes cells preserved within the memory pool with potentials that reflect the early preferential activation of multiple over single lineages. The phenotypes and epigenomes of CCR6+ cells are stable across cell divisions under noninflammatory conditions. Nonetheless, activation in polarizing and nonpolarizing conditions can yield additional functionalities, revealing, respectively, both environmentally induced and imprinted mechanisms that contribute differentially across the type 17 continuum to yield the unusual plasticity ascribed to type 17 cells.