bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel HVDC Power Transmission Architectures for Subsea Grid
Authors: Ray Anindya , Rajashekara Kaushik , Krishnamoorthy Harish
Published: April 2019

Subsea electrification is envisaged as one of the key building blocks of deep-water oil and gas (O&G) production. Present power transmission and distribution (T&D) schemes almost exclusively employ high voltage AC (HVAC) technology to drive the electrical processing units in the seabed, such as pump and compressor motors. Although HVAC transmission is reliable and simple to control, it exhibits a serious drawback with increasing step-out distance in terms of high reactive power requirements and reduction in peak power transfer capability for the subsea transmission cable. Moreover, most of the existing subsea T&D architectures employ a hub-and-spoke architecture with a single power receiving node. As a result, these systems are vulnerable to single-point failure.

In order to address the above issues, two novel subsea architectures, based on high voltage DC (HVDC) transmission, are proposed in this paper. HVDC offers a significant advantage over HVAC systems for longer transmission distances with additional power processing units embedded in the system. Both these architectures employ a subsea DC distribution bus concept to supply multiple subsea loads which represent current scenario of increasing subsea consumers. The performance of the proposed architectures is illustrated through simulation for distinct events such as rated power flow, load step-up/down and load side breaker closing. Relevant results are discussed to summarize the advantages and challenges for the proposed power transmission architectures.
A Simplified Four Phase Compositional Simulator for Asphaltene Evaluation
Authors: AlGhanem Fahad A. , Jessen Kristian
Published: April 2019

One of the most promising Enhanced Oil Recovery (EOR) methods is CO2 injection. However, if the oil contains asphaltenes, CO2 injection may cause asphaltene precipitation and introduce production related challenges. Conventional three-phase (gas/oil/water) compositional simulators are unable to predict precipitation of asphaltenes and multiphase compositional simulators are required. The use of detailed multiphase equilibrium calculations is very CPU intensive and commercial simulation packages often employ a hybrid model that may not capture the true physics at play.

Conflicting findings have been reported from experimental and theoretical studies: Some studies show that Asphaltene deposition, due to CO2 injection, takes place near the injection well, while others have reported that asphaltene deposition occurs near the production well. True multiphase equilibrium calculations can be used to demonstrate that both findings are possible and that many factors will affect the deposition behavior. Accordingly, a general statement such as CO2 injection causes more asphaltene precipitation relative to hydrocarbon (HC) gas injection is not always true. This added complexity indicates the need for multiphase compositional simulation to delineate asphaltene deposition behavior and quantity.

In this work, we propose a four-phase compositional simulator (gas/oil/asphaltene/water) to predict the asphaltene precipitation during CO2 and HC gas injection processes. A new hybrid formulation, based on a simple table look-up approach, is introduced to replace detailed multiphase calculations (gas/oil/asphaltene) at a CPU requirement that is comparable to two-phase (gas/oil) equilibrium calculations. A range of simulation models/scenarios are presented to test and validate the new formulation against detailed multiphase compositional simulation, and we demonstrate an excellent agreement between the hybrid model and the full multiphase calculations.

The proposed approach is easy to implement in commercial tools and provides a path to allow for more detailed studies of asphaltene precipitation and related production challenges.
Equipment Health Monitoring and Damage Prediction Using Mechanical Stress Soft Sensing Through Data Analytics
Authors: Williams Ryan Scott
Published: April 2019

Fatigue damage due to structural stress is a common problem for equipment used in offshore drilling such subsea connectors and subsea riser joints. Fatigue damage is characterized by the weakening of a structure or component of the equipment due to cyclic loading. Consistently operating the equipment above the operational parameters can lead to premature failure of the equipment causing unplanned downtime and posing a safety risk to nearby workers. There are several methods currently being used to determine cumulative fatigue damage as a way of assessing the operational life of machines used for drilling. Linear cumulative fatigue damage analysis is one of the most used methods for life prediction of a structure and components of equipment subjected to cyclic loading. The model involves examining the operational stress ranges caused by cyclic loading and comparing them to an established fatigue curve to estimate the total utilization and predict equipment failure. However, the linear damage rule (Miner's rule) has several limitations namely: The damage model often depends on complex, and time consuming, stress analysis depicting exact geometry and operating conditions.Damage can only be assessed subsequently, making it difficult to forecast use and plan scheduled maintenance.

This document presents the development of a mechanical stress soft sensing algorithm for determining real-time cumulative fatigue damage using finite element analysis with response surface methodology. The results in this document show that the new real-time cumulative damage determination approach could effectively help address the limitations of the current models by providing a means of determining real-time cumulative damage with little computational power.
Simulation Study Comparing Offshore Versus Onshore CO2 Well Blowouts
Authors: Oldenburg Curtis M. , Pan Lehua
Published: April 2019

We have simulated onshore and offshore blowouts of an idealized CO2 injection well using T2Well, a state-of-the-art coupled well-reservoir simulator. The purpose of the study is to understand dynamic multi-phase non-isothermal flow phenomena in CO2 wells to inform risk assessment studies for offshore geologic carbon sequestration sites. The scenario we chose consists of a vertical well of 3050 m length completed in a mature geologic carbon sequestration reservoir filled with CO2 connected to a horizontal surface pipe. At time zero, we assume the surface pipe was breached producing a 2-inch diameter hole. In the onshore scenario, the pipe blowout causes CO2 to enter the ambient air at 0.101325 MPa and 22.78 °C, whereas in the offshore scenario the blowout is into the water column at a depth of 50 m where pressure and temperature are 0.598 MPa and 22.78 °C, respectively. The simulations show that the overall CO2 leakage rates are very similar for the onshore and offshore scenarios, with subtle differences in flow rates of various phases likely arising from differences in pressure at the leakage point. Overall, the main differences between onshore and offshore CO2 blowouts are expected to arise mostly after discharge due to differences between how CO2 disperses in ambient air versus in the water column.
Assessment of Mass Gravity Flow Induced Seafloor Scour Impact on Stability of Mudmat Supported Subsea Structures
Authors: Trandafir Aurelian C.
Published: April 2019

Mass gravity flow phenomena resulting from mobilization of unstable sediments on submarine slopes are well recognized as a major geologic hazard for offshore infrastructure development. Previously published research pertaining to mass gravity flow impact on offshore infrastructure has focused on evaluating the direct impact loads generated by the flowing sediment mass in contact with the analyzed infrastructure component, such as a pipeline or a mudmat. In this study, the mass gravity flow impact on offshore infrastructure is addressed from a different perspective by investigating the potential for mass gravity flow induced seafloor scouring. Finite-element analysis is used to investigate the mobilization of near-seafloor sediments in a deepwater setting under the loads generated by a mass gravity flow event. Analysis results representative for a mass gravity flow in the far-field, near-field, and at the location of a mudmat supported subsea structure are presented and discussed in terms of failure mechanism, near-seafloor sediment deformation pattern and associated impact on stability of the subsea structure, in relation to flow thickness and position of the front of the flow relative to the subsea structure. For the case of a mass gravity flow in contact with the subsea structure, an example of failure envelope providing the ultimate lateral impact load from mass gravity flow required to cause instability of the structure, accounting for the flow induced mobilization of sediments underneath the mudmat, is also presented.
Substantially Improved Wind Power Performance
Authors: Baugh Benton Frederick , Whaley Paul Wayne , Harnett Stephen D. , Hammer Layne N. , Kraeger Zackary A. , Fultz Shannon K. , Lamascus Parker L.
Published: April 2019

The University took the approach of trying to get students interested in engineering as a career by focusing on how we might help America become more energy independent, particularly in their wind prone area. This paper is a report on the resulting actual middle school, high school and college student testing demonstrating that the performance of wind turbines can be increased by a factor of at least 10 by updating and revising "best practices". The results clearly show that wind turbine power is a function of the total blade area rather than the conventional understanding that it is a function of the swept area.

Includes test data and history of testing by university students, testing by students of area high and middle schools, and an explanation of why such a substantial improvement in performance is available at this time. This testing will lead not only to additional future student testing at the same size, and also a new generation of larger scale testing to confirm the results as something closer to a commercial size.
Safety Capability of an All-Electric Production System
Authors: Mahler Carsten , Glaser Markus , Schoch Simon , Marx Stefan , Schluenss Stefan , Winter Tobias , Popp Julian , Imle Sebastian
Published: April 2019

The all-electric control system, as proposed with this paper, provides improved HSE, reduced costs, and increases safety and reliability compared to an electrohydraulic system. This paper describes the approach for the development of a novel all-electric safety actuation system. Key to this concept is the centralized battery, which is utilized to provide the system with the required amount of energy during valve actuation for normal operation and in case of a power cut or communication loss. Since instantaneous power for valve operation is supplied by the battery, continuous power demand remains at a similar level for current electrohydraulic solutions.

This paper includes a detailed analysis to evaluate the safety and reliability capability of the proposed all-electric system. It also covers root causes for failure modes and suitable mitigations to prevent occurrence or for failure impact reduction. Further objective is the analysis of common cause failures, which are critical for safety function execution. The paper is a result of the work of a joint industry project.
Wear and Its Effect on Electrical Submersible Pump ESP Performance Degradation by Sandy Flow: Experiments and Modeling
Authors: Zhu Haiwen , Zhu Jianjun , Zhou Zulin , Rutter Risa , Zhang Hong-Quan
Published: April 2019

Multi-stage electrical submersible pump (ESP) is a frequently used artificial lift method, especially in high production wells. Severe wear and leakage can be caused by sand production from unconsolidated sandstone and proppant backflow. The loss of boosting ability and system stability under sandy flow condition is hard to be predicted, which not only reduces the production but also causes severe failures. In this study, a closed testing flow loop with a mixed type ESP is constructed to test pump performance and efficiency under water-sand flow. 64 hours total testing time is divided into several short intervals. After each interval test, the deteriorated head and efficiency of ESP with pure water were tested. More head loss was observed under low flow rate region, which is presumably caused by leakage through the secondary flow region. Head curve acquired in the test is compared to other studies to analyze the leakage effect in different regions. A leakage flow map including three different regions is provided. The seals’ ID/OD and clearances were measured after the pump was disassembled. The leakage effect in previous mechanistic ESP performance prediction model is modified based on test results. By using the appropriate geometries, the deteriorated head curve can be calculated. Compared to the test curves, the proposed model agrees well with the head degradation trend. The model can be further improved by adding abrasion and efficiency models with more available data.
Streamlined Natural Gas Treatment by Membranes Only
Authors: Dengel Udo , Karode Sandeep , Ding Yong
Published: April 2019

Offshore gas treatment faces constraints for space and weight limits. This paper will present an innovative concept of using only membranesto remove multiple contaminants, reduce weight, space and cost on offshore installations and becoming an enabler for gas monetization.

Membrane separation is a cost effective way to remove CO2 from natural gas. The typical offshore membrane treatment package usually consists of a relatively complex pre-treatment step followed by a simple membrane system to remove CO2.

The solution using only membranes for gas treatment consists of:

a first stage of poly (ether ether ketone) or PEEK membranes, resistant to the main impurities in natural gas, able to remove H2S, heavy hydrocarbons and water, thus essentially replacing the pre-treatment for offshore CO2 removal membrane packages

a second stage of poly-imide membranes with high CO2 / CH4 selectivity for CO2 removal

The membrane-only solution can be applied for treatment of large volumes of gas for pipeline specification to remove CO2 and other contaminants. Key benefits are simplicity of operation, compactness of footprint, weight reduction and a reduction in or elimination of adsorbent media replacements. Topside weight and cost reduction can increase gas treatment capacity and flexibility and are an enabler for gas monetization.

Due to their resistance to impurities PEEK membranes can also be used to treat flared gas for valorization through gas-to-power applications, thus reducing flaring. For gas-to-power applications, the gas will undergo some basic conditioning (such as hydrocarbons dew point, BTU adjustment, H2S removal) by a compact membrane unit to be used for power generation on the offshore platform.
Operational Excellence and Product Reliability Enhancement Through Big Data Analytics
Authors: Mulunjkar Amol M. , Deshpande Ashish P. , Steinke Stephen , Chartier Benjamin , Kuwertz Luke A.
Published: April 2019

Schlumberger, one of the world’s leading suppliers of oilfield technology, is a measurement and data-driven company that collects massive amounts of data in the course of its daily operations. These data, diverse in nature, are collected for use in various business and technical workflows. The data can be downhole, surface, post-analysis, and support functions from manufacturing, maintenance, asset management, and finance. Analysis of this Big Data has the potential to drive a step change in operational performance across multiple dimensions. However, accomplishing this step change is not easy to accomplish because often, the data are not well structured and are scattered across individual business systems that do not communicate well with each other. Most of the analysis of these scattered data occurs on a point basis, requiring the significant involvement of various experts and complex time-consuming manipulations. The results are short lived in that they cannot be tracked in real time and the effort expended is not applicable to other data sets or problems. Increasing data volumes, data diversity, and demand from engineers to record multiple new data attributes during the product or technology life cycle further limits the benefits of such a spot analytics process, with potentially severe impacts on the business due to inadequate decision support or missed opportunities.

This paper presents a developmental model and change processes, challenges faced and resolution approaches leading to digital transformation, and finally, the resulting value creation through building data visualizations and comprehensible decision-making tools.

Once the initial high-value data sets and visualizations are identified, automation opportunities can be exploited. These data sets become the foundation for predictive analysis and machine learning through artificial intelligence (AI) and Internet of things (IoT) to further influence product performance and development in support of customer needs.
Pore Pressure Prediction Before and During Drilling Applying the Four Zones Method
Authors: Shaker Selim S.
Published: April 2019

This method integrates the geological building blocks of sedimentation, dehydration to lithification and the formation water hydrodynamic forces associated with each of these phases. The current known conventional velocity – pore pressure transformation models are lacking this relationship.

In the current widely used conventional methods, it is controversial to consider the shallow section as normally pressured and at the same time extract a compaction trend from its petrophysical properties. Moreover, there is confusion about which part of the subsurface section the Effective Stress theorem should be applied to. The novelty of dividing the subsurface into four zones using this new approach reduces the risk of predicting the pore pressure before drilling and the uncertainty of its correct calibration during drilling.

This new pore pressure calculation is done separately in each zone based on the predominant formation-water dynamic. Normal hydrostatic pressure is only assigned to the loosely compacted very shallow section (A). Hydrodynamic zone B with upward formation water flow is associated with compaction and reduction of porosity due to sediments load. Petrophysical trends such as velocity, density, resistivity follows a compaction trend in this zone. As result of depositing shale seal in zone C, due to high stand sea level, fluid is prevented from permeating upward. This low permeable top seal is referred to as top of geopressure (TOG). The geopressured section of zone D below the pressure ramp in zone C follows a cascade outline where the pressure in permeable beds show linear trends and shale exhibits an exponential trend.

The petrophysical properties of the deeper shale beds below the top seal represent several passive compaction trends. Pore pressure prediction in the deep geopressured section D is derived from calculating at the same depth the disparity between the extrapolated velocity compaction trend (CT) values and the measured ones. A unique mathematical calculation is introduced here to establish the compaction trend (CT) instead of the manual graphically extrapolated so called NCT. Before drilling seismic velocity, semblance is a key for defining the four zones. Velocity – pore-pressure transformation modeling is an important aspect of the drilling cost for a proposed location. Moreover, LWD’s during drilling and conventional logs post drilling are the fine-tuning tools of calibrating the pre-drilling seismic-pressure model. The calibrated model is the backbone of any predicted pore pressure in future drilling locations in the same basin.

The pore pressure prediction applying this method facilitates assigning the casing setting and mud programs at the appropriate depths before drilling. Furthermore, it reduces the non-productive time (NPT) and challenges by assessing the subsurface formation pressure including the shallow water flow (SWF), risk of kicks and loss of circulation along the proposed bore-hole trajectory before moving rig on location.
Monitoring Stored CO2 to Document Permanence
Authors: Hovorka Susan Davis
Published: April 2019

Injection of CO2 into porous rocks deep in the subsurface intrinsically has a low risk of leakage for three reasons: (1) Although CO2 is buoyant compared to brine, layered rocks limit vertical migration. Injection zones are chosen with at least one well-qualified confining system that should isolate CO2 within the selected interval. (2) Capillary trapping of CO2 in the pore system, dissolution of CO2 into formation fluids, and sorption and reaction of CO2 with organics and minerals will further attenuate CO2 lateral or vertical migration. (3) Wells are designed to isolate fluids in the deep subsurface from the overlying water and other resources; even a poorly constructed well will greatly retard migration of stored CO2.

To add certainty to the planned storage, a monitoring program can be designed to document that the plume is migrating as predicted (and therefore that the planned-storage permanence is likely) and to assess any remaining uncertainties, for example, to further reduce well leakage or off-site migration risk.

In an offshore setting, time-lapse seismic is the most preferred tool. A survey collected prior to injection provides the baseline survey. Injected CO2 displaces water and also increases pressure. During repeat surveys, the resulting changes in seismic velocity are measurable. Subtracting the repeat surveys from the pre-injection survey provides a high-quality image of the areas where CO2 has migrated.

Other tools of high value are downhole-pressure measurements and wireline logs used to assess the zones at which CO2 is leaving the injection well(s). Gravity surveys are also used to assess the change in fluid density as CO2 is emplaced, and seismic sensors may be of value to assess microseismic response to injection. An available suite of environmental tools can be deployed to determine if any unexpected change occurs in the overburden, sediment, and water column. Advanced deployments such as fiberoptic cables and remotely operated sensor packages may have high value.

Complexities of and limitations to monitoring must be critically assessed. The material impact of loss of CO2 from storage is forward modeled to determine if tools and techniques selected are sensitive to the changes. For example, if natural gas charge is present in the subsurface, seismic change from injection of CO2 is likely to be small and may be less than noise. Only by rigorous documentation that leakage is detectable can the expected outcome, high-quality storage, be documented. New work is being undertaken to develop optimized and commercializable monitoring for storage projects in the Gulf of Mexico.

This work is related to a new multiyear project assessing the suitability of nearshore Gulf of Mexico for CO2 storage.
Aasta Hansteen Spar Inshore Pre-Service Operations
Authors: Edelson David , Jegannathan Manoj , Harris Tyler , Theckumpurath Basil , Selstad Henning , Krokeide Bjorn , Person Morten
Published: April 2019

This paper presents the overview of the Pre-Service operations for the Aasta Hansteen field development. The paper also covers the execution challenges, supporting engineering and procedures followed for the various activities.

The Aasta Hansteen Field development at a water depth of 1300m is the deepest field on the Norwegian Continental Shelf (NCS). The field is remotely located north of the Arctic Circle, in a particularly harsh environment 300km off the coast of Northern Norway, with 140km to the closest offshore installation.

In the past, the pre-service marine operations for Spar platforms were completed at the offshore field locations. The Aasta Hansteen development presented the opportunity to complete the entire pre-service operations in the sheltered waters of the deep Norwegian fjords, making it a unique, first-of-a-kind inshore pre-service operations for a Spar platform ever executed. This advantage also helped to significantly reduce the cost and complexity of the pre-service operations effort for the project.

There were several firsts in the industry for the Aasta Hansteen Spar platform, namely; Largest and heaviest Spar delivered, First Spar in Norwegian waters and subject to Norwegian rules, first full pre-service scope inshore in a fjord, first requirement for Structural Tank Inspection on a Spar Hull, first requirement for a Submergence Test, largest topside catamaran mating at 22,500 Te. Many of these firsts heavily influenced the planning and execution of the Pre-Service Operations for this project. The significance of these are also highlighted in this paper.
Smart Integration of Natural Gas Valorization Systems and Flexible Plant Installation in Existing and Low Capacity Gas Production Sites
Authors: Falsini Matteo , Conforti Filippo
Published: April 2019

The increasing demand of energy efficiency, the evolution of emission regulatory and the limited investments allocation, increases the attractiveness for flexible gas valorization systems [GGFR]. Gas valorization system can be considered all the technical solution i.e process or new equipment installation that allow to use wasted gas sources to produce electricity of mechanical power for different application.

The recovery of associated or stranded gases presents various complexities especially if applied to remote locations. For this reason, to maximize synergies with the existing premises, a flexible design and pre-assembled solutions might be recommended.

This paper presents, the integration of flexible installation solutions with natural gas valorization systems. This approach is finalized to maximize the production capability of a hydrocarbon production site with a low impact on existing infrastructures and relocation possibility.

On this regard, the main emphasis is placed to the following actions: The integration of flexible systems in the gas recovery processes,The upgrade of existing equipment to resolve production bottleneck,The use of mobile technology to accommodate plant flexibility.

During the plant life cycle, operating conditions of some critical links of the production chain need to to be adjusted. In this case the upgrades of processes and equipment flexibility helps to prevent inefficiencies that may result in gas flow underutilization or associated gas flaring.

Moderate natural gas flows, either from oil production associated products or stranded gas reserves, limits the economic viability of a gas valorization system. For this reason, solutions integrating the standard design balance of plant and the mobile truck architecture are technical choice that provide beneficial impact on the site effectiveness and economics. Moreover, mobile plants provide the further advantage to be reused in different sites through a simple relocation and minor adjustment.

Offshore oil plants may not include gas boosting/offload or spare power generation solutions while small space and limited load capability generate additional complexities. In these cases, a dedicated approach like the construction of floating modular systems to be connected to the existing structure represent a viable solution.
Demonstrating the Feasibility of New-Build Hull-Platform for FPSO in Various Oil Field
Authors: Sogawa Yasuhiro , Tanaka Shigeru
Published: April 2019

It is a challenging problem to achieve low cost and fast-track construction for new-build FPSO hulls. In order to cope with this problem, the authors developed and reported unique modular design and multi-yard construction concept, "noah-FPSO Hull" [1][2][3]. After that, the authors continued to improve its design and expanded its flexibility for harsh environment and customer's requests. As a result, new standardized fore/aft modules and cargo tank module have been developed to expand the flexibility. This paper presents the design of the newly developed modules and the feasibility for harsh environment.
Application of the Findings of the PISA Joint Industry Project in the Design of Monopile Foundations for a North Sea Wind Farm
Authors: Manceau Sebastien , McLean Robert , Sia Anna , Soares Marisa
Published: April 2019

Monopiles are the most common foundation type in the offshore wind industry. Their design is largely dependent on the ability to accurately model the soil-structure response of the foundation, with more refined modelling approaches enabling significant reductions in required embedment depth, fabrication cost and installation risk. The PISA joint industry project (JIP) has been completed in recent years with the objectives of developing a more refined soil-structure response modelling method compared to other available methods such as the API p-y curve approach. The scope of this paper is to detail how the PISA recommendations have been implemented on a real offshore wind farm project located in the UK North Sea, identifying how the findings can be incorporated into a combined geotechnical and structural analysis approach to enable efficient serial design of multiple foundations for wind turbines.

The paper presents how existing design processes and criteria can be modified to take into account the recommendations of the PISA JIP for use in design. Discussion will be provided on the following procedures: calibration of the PISA 1-D soil response formulations to site specific conditions; the combination of the homogeneous sand and clay formulations to accurately model soil-structure response in layered soil profiles; and, consideration of the effects of cyclic loading in conjunction with the use of the PISA monotonic soil response formulations.

Results will be presented to demonstrate the calibration of the PISA 1-D soil response formulations to a layered soil site. Discussion will also be provided on the significant monopile lengths savings achieved when using a PISA approach compared to an API p-y curve approach. The monopile mass reduction will be illustrated against trends derived from installed monopiles. Observations will be provided on how the use of a PISA based approach can affect the governing design cases and how this is likely to impact on monopile design for future projects. Discussions and conclusions will also be presented on the challenges of implementing the PISA recommendations in monopile design for real projects and what additional work is required to enable further costs savings in implementing the new design approach.

The PISA JIP recommendations are the cutting edge in monopile foundation design. The paper will provide discussion on how these recommendations can be effectively implemented in design based on experience from the foundation design for a real offshore wind farm. The wind farm in question will be one of the first constructed for which foundations have been designed using a PISA based method, demonstrating the significant CAPEX savings possible using the PISA approach.
Extracting Value from Data Using an Industrial Data Platform to Provide a Foundational Digital Twin
Authors: Laborie Francois , Røed Ole Christian , Engdahl Geir , Camp Audrey
Published: April 2019

Oil & Gas data currently exists within a world of data silos. Lack of data is not the challenge. A wide variety of data is collected, including sensor values, P&IDs, ERP, and depth-based trajectories. Rather, the challenge pertains to data usefulness. The root of the problem is a combination of factors, including poor data infrastructure, incompatible operational data systems, and restricted data access. All this translates to a low maturity of digitalization across the Oil & Gas industry. To date, digitalization efforts have been limited to pilot projects, proofs of concept and case studies, with no large-scale operationalized projects.

Aker BP, one of Europe's largest independent Oil & Gas companies, has broken through the typical roadblocks by deploying an industrial data platform across all five of its operational assets. The platform aggregates and processes data from sensors and contextualizes it, structuring it in relation to process diagrams, production information, 3D-models, and event data (maintenance, incidents). Everything linked in the real world is also linked in the platform. This has dramatically reduced the cost of integration and maintenance, while simultaneously enabling scalability, speed of development, and data openness throughout the Aker BP organization. The data platform handles live and historical data for close to 200,000 sensors, with a peak transfer of 800,000 data points per second. Internal and external experts are able to apply state-of-the-art algorithms to visualize and solve critical business problems. A range of third-party applications and data scientists also use the 1+ trillion data points in the platform to create value and support Aker BP's strategy for day-to-day operations and long-term digital transformation.

To realize the promise of digitalization, unlocking the value of data must be made a priority within the Oil & Gas industry. This paper will describe the implementation of the industrial data platform, explaining how data streamed from many, disparate, underlying systems is contextualized in the data platform to provide a holistic view of all processes and operations, thus creating a foundational digital twin for each asset, ready to empower machine learning applications for optimization and automatization, as well as human-facing applications, such as advanced visualizations and apps for the digital field worker.
Feasibility Analysis on Using a Group of Wind Turbines as a Hub to Supply Electricity to Offshore Oil and Gas Platforms in the Gulf of Mexico
Authors: Haces-Fernandez Francisco , Li Hua , Ramirez David
Published: April 2019

Previous research indicated that interconnecting offshore platforms in the Gulf of Mexico with wind energy and the onshore grid can provide significant advantages. This research considered groups of offshore wind turbines as energy hubs to provide electricity to nearby offshore platforms, including the evaluation of energy deficits caused by wind wakes. The proposed research idea allows platforms to improve energy efficiency, save fuel, reduce air pollution, and increase income by selling surplus energy. The energy output of these wind turbines was estimated considering wake effects. Diverse layouts were modeled applying meteorological and geographical data integrated with wind wake models to solve a realistic wind farm layout optimization problem. The research created a methodology to optimize a group of offshore wind turbines performance in the Gulf of Mexico, minimizing negative interference while maximizing power output. Results indicated that an important number of locations of offshore oil and gas platforms were able to provide adequate levels of wind energy. Variable wind directions cause changes on the behavior of the turbulent wakes. Therefore, the layout of wind turbines needs to be optimized to minimize negative interaction while maximizing power output under different wind conditions. Furthermore, the analysis revealed the feasibility of installing, in particular optimal locations, wind farms that would simultaneously serve several offshore platforms in close proximity (as hubs) while the system remains connected to the onshore grid.
Forensic Data & Decisions: Utilizing Data Intended for Other Purposes
Authors: Wisch David , Huyse Luc
Published: April 2019

During installation of the Big Foot TLP, nine of the 16 pre-installed tendons fell to the seafloor prior to completion of installation. a comprehensive Root Cause Analysis was undertaken to determine the "cause" of the incident. During the early investigative phase, a number of sources of data were identified. Two particular information sets were gathered, interrogated, processed, etc. to extract usable patterns and values to aid in decision making. A third composite data set of deepwater current values was coupled to extract additional insights. All data sets were designed for installation support and not intended for a forensic investigation. Identification of the data, understanding original intent, multi-stage filtering and conclusions will be illustrated.

One is a time series containing x, y, z spatial data of a common location on each of the 16 pre-installed tendon assemblies and the second being non-periodic discrete air volume measurements of buoyancy devices. The time series data contained repetitive data points, contained spurious readings, etc. The multi-stage automatic and manual filtering processes utilized to develop non-periodic traces useful for insight and decision making is described. Accompanying this discussion will be the description of original intent and the adaptation from intended use to RCA value. The second data involved non-periodic air volume measurements. Initial interpretation of data during installation was sufficient for operational purposes. A Root Cause Analysis team analyzed the data including use of correlative time series unrelated to the measurement to identify telling patterns useful in decisions.

The absolute as recorded data was unable to provide sufficient confidence using standard data processing techniques. Target manual filtering and correlative comparisons provided useful and valuable decision-making insights. The ability to use data designed for specific purposes not aligned with ultimate usage for RCA purposes is shown
The Art of Disintegration – Ten Years in Review of Disintegrable Metals and Downhole Tools
Authors: Xu Zhiyue , Zhang Zhihue
Published: April 2019

Disintegrable metal (DM) has proven its market value since the first set of disintegrable frac balls were successfully employed in a shale well in Bakken field about 10 years ago. The DM material technology and tools have changed the downhole tool operation landscape with unprecedented efficiency, reliability, by reducing the operational complexity or simplifying tool installation or actuation procedures. This paper reviews the advancement of DM materials technology, arts to engineer and control the disintegrating performance, various DM downhole tools, and the field operation case studies over the last 10 years.

Review of the art of disintegration of disintegrable metals is based literature surveys and author’s own research and development results. Disintegrable metals currently available on the market could be classified into two different metallic systems based on their base metal chemistry: magnesium based disintegrable metal and aluminum-based disintegrable metal. Both systems are light weight, strong as steel and completely disintegrable in typical downhole environments. The paper will review the material design, microstructure, and properties of the two metallic systems, then discuss how to match material properties with requirement of downhole disintegrable tools, and finally share field operation cases.

Most of DM materials have micro-galvanic cells built into their microstructures and disintegrate through galvanic corrosion when contacting with wellbore fluid. Key variables affecting the rate of disintegration include material composition, well temperature, tool surface area exposure to a fluid, fluid type, concentration and agitation conditions. The review reveals that it is critical to select the correct DM material to match the application environment for a successful field application of disintegrable tool. In today’s multi-stage hydraulic fracturing market, DM tools would be the preferred technology of choice when DM material selection and tool design and performance match properly to the needs of hytraulic fracture operation of a well.

The thermodynamics and kinetics that control the disintegration performance of DM tools, or the art of disintegration, will be reviewed and shared with the readers. The profound arts and engineering of DM materials and field case studies shared by this paper would shed light on how to make sound selection of DM materials, design optimal DM tools for a defined well or field application, develop the best field operation procedures, and execute a MD application efficiently.
Aasta Hansteen Spar and Topside Fabrication
Authors: Kim Dong Hyub , Seberg Lars Cato , Witsøe Stig Arne
Published: April 2019

This paper describes the fabrication of the world' largest and most complex Truss Spar Platform, Aasta Hansteen, built for the Norwegian Continental Shelf (NCS) to be operated by Equinor. It was built according to NORSOK standard, Norwegian governing laws and regulations and other Company requirements.

Hyundai Heavy Industries (HHI) was awarded an EPC Contract (Engineering, Procurement, and Construction) for the Topside of Spar Platform, and HHI and TechnipFMC formed a Consortium responsible for the overall delivery of the Spar Hull. TechnipFMC was responsible for the design, engineering and equipment procurement, whereas HHI was responsible for Fabrication and delivery.

This paper addresses the characteristics of the design of Aasta Hansteen Spar Platform and highlights critical aspects of the Construction Method of Spar Hull at HHI's offshore yard in Ulsan, Korea.
Shallow Water Testing of 9 - 12 MVA Variable Speed Drive for Subsea Installation
Authors: Lendenmann Heinz , Laneryd Tor , Virtanen Esa , Cagienard Raphael , Wagner Thomas , Missing Kim
Published: April 2019

The electrical Variable Speed Drive (VSD) system presented is designed for installation on the sea floor to drive nearby electric motors for pumps and gas compressors. A modular concept of the VSD is developed and intended to operate a wide range of subsea motors of powers from 0.5 to 18 MVA, with voltages from 2.0 kV to 7.2 kV or more, and fundamental frequencies up to 300 Hz. Step-out distances from a few km to over 600 km can be accommodated.

The pressure compensated design effectively removes limits as to the depth of deployment. Pressure compensation is achieved by submerging the drive hardware including the drive transformer in a dielectric liquid which also acts as coolant. The electric power components, including capacitors, semiconductors, and the control electronics are designed with increased margins and redundant hardware, pressure resistance, and materials chosen for compatibility with the dielectric liquid, to achieve a highly reliable design of the overall VSD.

The drive was deployed into shallow water in a harbor in Vaasa Finland for testing. A top side station was built implementing a "Power-In-the-Loop" approach, where the VSD output energy is recovered back into the drive input such that the grid supply only provides the lost power, but not the much higher circulated power.

The drive operated more than 1000 h at 22 kV input and 6.9 - 7.2 kV output voltage at different power levels. We conclude from this first shallow water test, that all components of the VSD system work properly together up to 1000 A output current. Different operation conditions reflecting the envisioned application, including redundancy capability were successfully tested. The thermal performance was extensively verified, including an optional external heat exchanger to achieve high ratings even in warm waters.

To our knowledge this is the first time a medium voltage drive is operated at 9 to 12 MVA for an extended time submerged in a sea water environment. All its modules are designed to operate down to depths of 10’000 ft / 3000 m or more and are concluding qualification according to API17F and SEPS 1002.
Biodegradable Anti-Agglomerant Chemistry for Hydrate Plug Prevention in Various Production Conditions
Authors: Monteiro Deepak Steven , Vo Loan Kim , Prince Philippe , Bodnar Scot Harris
Published: April 2019

Performance of anti-agglomerants (AAs) depends on many factors, including salinity, water cut (WC), characteristics of the hydrocarbons, gas composition, reservoir conditions, production system conditions, and especially AA stability at the application conditions. Most AAs are surfactants, with one or multiple long hydrophobic tails and a charged hydrophilic head. This class of chemistry is often not easily degraded in the environment and can, therefore, be eliminated from consideration for application in environmentally sensitive regions. This paper presents the development of an AA that can be applied under a wide range of production conditions and is unique because of its ready biodegradability [>60% compared to other AAs, which either are not biodegradable (<20%) or can only achieve inherent biodegradability of 20 to 60%].

Rocking cell testing was conducted to determine the performance boundaries of the AA chemistry. Light, medium, and dark oils from various fields were used to evaluate the performance of the AA in aqueous phases ranging from condensed water (effectively, 0% salinity) to high salinity (~12%). Test results were categorized as "pass" for transportable hydrate slurries and "fail" if the systems plugged, and/or showed large hydrate crystals, and/or resulted in high slurry viscosity. Visual observations throughout the test and proximity sensor data provided qualitative and quantitative representations of the behavior of fluids in each cell. Water quality and emulsion tendency testing were conducted to verify that the AA would be suitable for offshore use and operable at topside. Biodegradation testing of the AA was conducted in seawater according to OECD 306 (1992).

Systematic study demonstrated strong versatility for application of this AA to help prevent hydrate blockages in pipelines. Optimizing the head and tail length of the molecule was crucial for allowing it to treat a wide range of salinities, WCs, and oils with different API gravities. No sign of hydrate blockage was observed when applying the designed AA at minimum effective dosage (MED). The optimized product demonstrates overboard oil and water quality, thereby eliminating the need for an emulsion breaker and/or a water clarifier. The presented AA has a ready biodegradability of 61.8% [greater than 60% is categorized as readily biodegradable using OECD 306 (1992) methodology] and has been successfully implemented to treat hydrate plugging in the Gulf of Mexico (GOM).
Bayesian Stratigraphy Integration of Geophysical, Geological, and Geotechnical Surveys Data
Authors: Medina-Cetina Zenon , Son Jungrak , Moradi Moslem
Published: April 2019

This paper introduces a probabilistic approach to significantly improve offshore site characterization from integrated geophysical, geological and geotechnical survey data, and from different technologies used from within each of these disciplines. The proposed Bayesian stratigraphy integration methodology is based on the sequential integration of available evidence (experimental observations, model predictions and experts’ beliefs), which allows for the reduction of uncertainty and improve the quality of geospatial analysis translated into higher stratigraphy resolution and higher confidence on the determination of sediments’ mechanical characteristics. A synthetic case study for a 2D heterogeneous shallow offshore soil media is presented to illustrate the overall methodology. One application of probabilistic cluster identification based on geological data is discussed (e.g. 1D density upscaling profile), as this is then transferred to a probabilistic geophysical inversion, including the corresponding uncertainty propagation and.