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.
{"title":"The Art of Disintegration – Ten Years in Review of Disintegrable Metals and Downhole Tools","authors":"Zhiyue Xu, Zhi-hong Zhang","doi":"10.4043/29624-MS","DOIUrl":"https://doi.org/10.4043/29624-MS","url":null,"abstract":"\u0000 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.\u0000 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.\u0000 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.\u0000 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.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89922582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The reliability of power semiconductor switches is important when considering their vital role in power electronic converters for downhole subsea applications. Respect to technology advancements in material sciences, power MOSFETs with wide band gap materials have been proposed such as silicon carbide (SiC) and gallium nitride (GaN) as an alternative to existing silicon (Si) based MOSFETs and IGBTs. However, reliability analysis should be performed before substituting SiC-MOSFETs in the place of existing Si-MOSFETs and IGBTs. Due to costly equipment of experimental test setup for accelerated life test, a good reliable and precise simulation-based test bench should be used to test the life test procedure before implementing actual hardware. Therefore, this paper introduces a power cycle (PC) test bench for accelerated life testing for reliability assessment of SiC-MOSFET in harsh offshore environment. The introduced test bench is a simulation-based of power switch in SimScape and LTspice and has been validated with datasheet of 1.2 kV SiC-MOSFET, CAS300M12BM2 by CREE. Preliminary hardware circuits are also shown for further experimental tests. The captured data from the Device-Under-Test (DUT) in different ambient temperatures are envisioned and provide critical information about the failure mechanisms and lifetime characteristics of power devices. The provided lifetime characteristics data of SiC-MOSFET can be used to statistically estimate the Remaining-Useful-Lifetime (RUL) of component in a real application such as downhole motor drives.
{"title":"Power Cycle Test Bench for Accelerated Life Testing for Reliability Assessment of SiC-MOSFET in Extreme Offshore Environment","authors":"A. Sadat","doi":"10.4043/29368-MS","DOIUrl":"https://doi.org/10.4043/29368-MS","url":null,"abstract":"\u0000 The reliability of power semiconductor switches is important when considering their vital role in power electronic converters for downhole subsea applications. Respect to technology advancements in material sciences, power MOSFETs with wide band gap materials have been proposed such as silicon carbide (SiC) and gallium nitride (GaN) as an alternative to existing silicon (Si) based MOSFETs and IGBTs. However, reliability analysis should be performed before substituting SiC-MOSFETs in the place of existing Si-MOSFETs and IGBTs. Due to costly equipment of experimental test setup for accelerated life test, a good reliable and precise simulation-based test bench should be used to test the life test procedure before implementing actual hardware. Therefore, this paper introduces a power cycle (PC) test bench for accelerated life testing for reliability assessment of SiC-MOSFET in harsh offshore environment. The introduced test bench is a simulation-based of power switch in SimScape and LTspice and has been validated with datasheet of 1.2 kV SiC-MOSFET, CAS300M12BM2 by CREE. Preliminary hardware circuits are also shown for further experimental tests. The captured data from the Device-Under-Test (DUT) in different ambient temperatures are envisioned and provide critical information about the failure mechanisms and lifetime characteristics of power devices. The provided lifetime characteristics data of SiC-MOSFET can be used to statistically estimate the Remaining-Useful-Lifetime (RUL) of component in a real application such as downhole motor drives.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78505592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Catina Geselschap, G. Meskers, R. V. Dijk, Ivan van Winsen
The Digital Twin, Heerema Simulation Center (HSC), is able to capture the offshore behavior in a realistic real-time digital environment with high fidelity hydrodynamics and physics and real operator stations. This digital tool completely changed engineering in all phases of the project life cycle since its first use in 2015. Its unique capacity is to ‘Engineer with the Human Factor in the loop’ independent if this Human Factor is the client, designer, fabricator, marine warranty surveyor or the offshore operator. In the conventional engineering tools the Human Factor cannot be included and in the conventional engineering process the preparation is done by engineers without much involvement of the operators. It is as if engineering and execution are separate worlds. Being able to bring these worlds together efficiently in an early stage has already led to an efficiency improvement for all parties (i.e. client, fabricator and offshore operator) involved and has improved the Operational Excellence offshore. In this paper the results of three simulated cases will be described to explain the way the Digital Twin is used for different purposes and objectives and what sort of results can be achieved from ‘Engineering with the Human Factor in the loop’. The Digital Twin is an exceptional tool in our Digital Journey that speeds up the process of implementing changes for a more efficient and safer offshore world.
{"title":"Digital Twin - Engineering with the Human Factor in the Loop","authors":"Catina Geselschap, G. Meskers, R. V. Dijk, Ivan van Winsen","doi":"10.4043/29627-MS","DOIUrl":"https://doi.org/10.4043/29627-MS","url":null,"abstract":"\u0000 The Digital Twin, Heerema Simulation Center (HSC), is able to capture the offshore behavior in a realistic real-time digital environment with high fidelity hydrodynamics and physics and real operator stations. This digital tool completely changed engineering in all phases of the project life cycle since its first use in 2015. Its unique capacity is to ‘Engineer with the Human Factor in the loop’ independent if this Human Factor is the client, designer, fabricator, marine warranty surveyor or the offshore operator.\u0000 In the conventional engineering tools the Human Factor cannot be included and in the conventional engineering process the preparation is done by engineers without much involvement of the operators. It is as if engineering and execution are separate worlds. Being able to bring these worlds together efficiently in an early stage has already led to an efficiency improvement for all parties (i.e. client, fabricator and offshore operator) involved and has improved the Operational Excellence offshore.\u0000 In this paper the results of three simulated cases will be described to explain the way the Digital Twin is used for different purposes and objectives and what sort of results can be achieved from ‘Engineering with the Human Factor in the loop’.\u0000 The Digital Twin is an exceptional tool in our Digital Journey that speeds up the process of implementing changes for a more efficient and safer offshore world.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76335484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The concept of macro-element modelling – which was first introduced almost 30 years ago – has proven to be a convenient and accurate technique for modelling offshore foundations, but historically these models have mainly been used for academic purposes. Recent developments in foundation modelling now allow for application of such models in engineering practise and design. One such example is the family of new macro-element models that have been developed in the research project REDWIN to represent the foundation behaviour in dynamic analyses of Offshore Wind Turbines (OWTs). These models exhibit characteristic foundation behaviour such as nonlinearity, coupling of the load from different load components and hysteretic load dependent damping. This paper presents two of the REDWIN models, one applicable for monopile foundations and one for skirted suction caisson foundations. Use of the models are demonstrated through two practical problems that reflect typical design analyses of OWTs: the first example shows a fatigue damage assessment for a monopile, and the second considers an extreme load event for a suction bucket jacket. The structural response is computed using the REDWIN foundation models and compared with the response based on distributed API p-y springs for the monopile and clamped legs at seabed for the jacket. Special emphasis is devoted to how the model input is obtained to guide readers on practical use of the models.
{"title":"A Family of Practical Foundation Models for Dynamic Analyses of Offshore Wind Turbines","authors":"A. Page, A. Løkke, K. Skau, J. D. Vaal","doi":"10.4043/29463-MS","DOIUrl":"https://doi.org/10.4043/29463-MS","url":null,"abstract":"\u0000 The concept of macro-element modelling – which was first introduced almost 30 years ago – has proven to be a convenient and accurate technique for modelling offshore foundations, but historically these models have mainly been used for academic purposes. Recent developments in foundation modelling now allow for application of such models in engineering practise and design. One such example is the family of new macro-element models that have been developed in the research project REDWIN to represent the foundation behaviour in dynamic analyses of Offshore Wind Turbines (OWTs). These models exhibit characteristic foundation behaviour such as nonlinearity, coupling of the load from different load components and hysteretic load dependent damping.\u0000 This paper presents two of the REDWIN models, one applicable for monopile foundations and one for skirted suction caisson foundations. Use of the models are demonstrated through two practical problems that reflect typical design analyses of OWTs: the first example shows a fatigue damage assessment for a monopile, and the second considers an extreme load event for a suction bucket jacket. The structural response is computed using the REDWIN foundation models and compared with the response based on distributed API p-y springs for the monopile and clamped legs at seabed for the jacket. Special emphasis is devoted to how the model input is obtained to guide readers on practical use of the models.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73196703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kalicharan Mahasivabhattu, Deepti Bandi, S. Singh, Pankaj Kumar
A lot of data in the engineering world exists in the form of paper drawings and documents. Technically, these are considered as "unstructured data [1]"as it is difficult to extract content from the drawings using traditional programs as compared to data stored in databases. These drawings are often used for design and maintenance activities in both greenfield and brownfield projects. Today, digital is a key enabler in oil and gas to increase workforce efficiency. Hence there is a growing need to get the dumb drawings digitized. However, the only means of converting these drawings into digital format is to manually re-draw them. With the emergence of technologies like Computer Vision, Optical Character Recognition(OCR) and Natural Language Processing(NLP), we no longer need to depend on human cognitive capabilities to process information from a drawing. Artificial Intelligence(AI) systems can be trained to recognize the visual content in drawings and provide a simplified context. AI based algorithms can read a scanned Process and Instrumentation Diagram (P&ID) to recognize the graphical content of the drawing like instruments, tags, pipelines, text etc. The information extract that AI generates from a dumb drawing can later be passed to an automation script to create a new digital version. This paper emphasizes the use of Artificial Intelligence in processing a scanned drawing and automatically redraw it on a digital platform. Adapting this approach can bring considerable advantage in the pursuit of going digital.
{"title":"Engineering Data Management Using Artificial Intelligence","authors":"Kalicharan Mahasivabhattu, Deepti Bandi, S. Singh, Pankaj Kumar","doi":"10.4043/29358-MS","DOIUrl":"https://doi.org/10.4043/29358-MS","url":null,"abstract":"\u0000 A lot of data in the engineering world exists in the form of paper drawings and documents. Technically, these are considered as \"unstructured data [1]\"as it is difficult to extract content from the drawings using traditional programs as compared to data stored in databases. These drawings are often used for design and maintenance activities in both greenfield and brownfield projects. Today, digital is a key enabler in oil and gas to increase workforce efficiency. Hence there is a growing need to get the dumb drawings digitized. However, the only means of converting these drawings into digital format is to manually re-draw them.\u0000 With the emergence of technologies like Computer Vision, Optical Character Recognition(OCR) and Natural Language Processing(NLP), we no longer need to depend on human cognitive capabilities to process information from a drawing. Artificial Intelligence(AI) systems can be trained to recognize the visual content in drawings and provide a simplified context. AI based algorithms can read a scanned Process and Instrumentation Diagram (P&ID) to recognize the graphical content of the drawing like instruments, tags, pipelines, text etc. The information extract that AI generates from a dumb drawing can later be passed to an automation script to create a new digital version.\u0000 This paper emphasizes the use of Artificial Intelligence in processing a scanned drawing and automatically redraw it on a digital platform. Adapting this approach can bring considerable advantage in the pursuit of going digital.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80120203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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 m
{"title":"Pore Pressure Prediction Before and During Drilling Applying the Four Zones Method","authors":"S. Shaker","doi":"10.4043/29517-MS","DOIUrl":"https://doi.org/10.4043/29517-MS","url":null,"abstract":"\u0000 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.\u0000 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.\u0000 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.\u0000 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.\u0000 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 m","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87295173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinbo Chen, J. Newlin, Meng Luo, Heping Zhang, C. Hadley, Shuang Hu
Riser-soil interactions have significant influence on the fatigue assessment of steel catenary risers (SCRs) near the touch down zones (TDZs), and can be critical in realizing a competitive SCR design and in extending a SCR design life. The motivation of the paper is to share the proprietary model test data and research/ design experience accumulated over the past three decades on the riser-soil interactions with the riser engineering community in order to deepen the understanding of this complex problem and to realize economical SCR designs. The objectives are (i) to present a fully nonlinear hysteresis model that captures the loading history of the riser-soil interactions at TDZs in the vertical direction for SCRs, and (ii) to propose a simplified equivalent linear elastic vertical stiffness for SCRs at TDZs for quick fatigue assessments. The paper begins with the mathematical formulation of the nonlinear model and the equivalent linear model for riser-soil interactions. Then the proposed model is verified through the consistent predictions from time-domain and frequency-domain simulations of an SCR from a Tension Leg Platform (TLP), the close agreement between the proposed model predictions and small scale pipe-soil interaction model test results, reduced scale sectional SCR model test results, and the latest study in the literature.
{"title":"Practice of Riser-Soil Interactions at Touch Down Zones for Steel Catenary Risers","authors":"Jinbo Chen, J. Newlin, Meng Luo, Heping Zhang, C. Hadley, Shuang Hu","doi":"10.4043/29553-MS","DOIUrl":"https://doi.org/10.4043/29553-MS","url":null,"abstract":"\u0000 Riser-soil interactions have significant influence on the fatigue assessment of steel catenary risers (SCRs) near the touch down zones (TDZs), and can be critical in realizing a competitive SCR design and in extending a SCR design life. The motivation of the paper is to share the proprietary model test data and research/ design experience accumulated over the past three decades on the riser-soil interactions with the riser engineering community in order to deepen the understanding of this complex problem and to realize economical SCR designs. The objectives are (i) to present a fully nonlinear hysteresis model that captures the loading history of the riser-soil interactions at TDZs in the vertical direction for SCRs, and (ii) to propose a simplified equivalent linear elastic vertical stiffness for SCRs at TDZs for quick fatigue assessments. The paper begins with the mathematical formulation of the nonlinear model and the equivalent linear model for riser-soil interactions. Then the proposed model is verified through the consistent predictions from time-domain and frequency-domain simulations of an SCR from a Tension Leg Platform (TLP), the close agreement between the proposed model predictions and small scale pipe-soil interaction model test results, reduced scale sectional SCR model test results, and the latest study in the literature.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86851635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Marques, Pedro Costa, Filipa Castro, Manuel Parente
The Earth’s surface is mostly water-covered and the ocean is the source of a significant slice on natural resources and renewable energies. However, only a small fraction of the ocean has been surveyed. Being able to estimate the 3D model of the environment from a single video eases the task of surveying the underwater environment, saves costs and opens doors to autonomous exploration of unknown environments. In order to estimate the 3D structure of a vehicle’s surrounding environment, we propose a deep learning based Simultaneous Localization and Mapping (SLAM) method. With our method, it is possible to predict a depth map of a given video frame while, at the same time, estimate the movement of the vehicle between different frames. Our method is completely self-supervised, meaning that it only requires a dataset of videos, without ground truth, to be trained. We propose a novel learning based depth map prior using Generative Adversarial Networks (GANs) to improve the depth map prediction results. We evaluate the performance of our method on the KITTI dataset and on a private dataset of subsea inspection videos. We show that our method outperforms state of the art SLAM methods in both depth prediction and pose estimation tasks. In particular, our method achieves a mean Absolute Trajectory Error of 1.6 feet in our private subsea test dataset.
{"title":"Self-Supervised Subsea SLAM for Autonomous Operations","authors":"F. Marques, Pedro Costa, Filipa Castro, Manuel Parente","doi":"10.4043/29602-MS","DOIUrl":"https://doi.org/10.4043/29602-MS","url":null,"abstract":"\u0000 The Earth’s surface is mostly water-covered and the ocean is the source of a significant slice on natural resources and renewable energies. However, only a small fraction of the ocean has been surveyed. Being able to estimate the 3D model of the environment from a single video eases the task of surveying the underwater environment, saves costs and opens doors to autonomous exploration of unknown environments. In order to estimate the 3D structure of a vehicle’s surrounding environment, we propose a deep learning based Simultaneous Localization and Mapping (SLAM) method. With our method, it is possible to predict a depth map of a given video frame while, at the same time, estimate the movement of the vehicle between different frames. Our method is completely self-supervised, meaning that it only requires a dataset of videos, without ground truth, to be trained. We propose a novel learning based depth map prior using Generative Adversarial Networks (GANs) to improve the depth map prediction results. We evaluate the performance of our method on the KITTI dataset and on a private dataset of subsea inspection videos. We show that our method outperforms state of the art SLAM methods in both depth prediction and pose estimation tasks. In particular, our method achieves a mean Absolute Trajectory Error of 1.6 feet in our private subsea test dataset.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80679678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jang-Whan Kim, Hyunchul Jang, Zhi-rong Shen, S. Yeon
This paper summarizes an on-going effort by SNAME OC-8 CFD Task Force to provide guidelines on wind-load estimation by CFD simulation. The intention of the guidelines is to help the industry to obtain reliable and accurate estimations of wind load on offshore floating facilities using CFD technology, for the purposes of stability, global-performance and mooring analyses. The starting point of the guidelines is CFD modeling practices collectively developed by ten participants of the Task Force. Blind validation of the wind loads from CFD simulations has been made for a semisubmersible with simplified topsides geometry. Comparison of the wind loads from independent CFD simulations from the participants confirmed that CFD can provide reliable and accurate wind load with fewer uncertainties in the simulation (or test) set up than wind-tunnel testing. A roadmap to develop the guidelines based on the CFD modeling practices is proposed.
{"title":"Developing Industry Guidelines for the CFD-Based Evaluation of Wind Load on Offshore Floating Facilities","authors":"Jang-Whan Kim, Hyunchul Jang, Zhi-rong Shen, S. Yeon","doi":"10.4043/29270-MS","DOIUrl":"https://doi.org/10.4043/29270-MS","url":null,"abstract":"\u0000 This paper summarizes an on-going effort by SNAME OC-8 CFD Task Force to provide guidelines on wind-load estimation by CFD simulation. The intention of the guidelines is to help the industry to obtain reliable and accurate estimations of wind load on offshore floating facilities using CFD technology, for the purposes of stability, global-performance and mooring analyses. The starting point of the guidelines is CFD modeling practices collectively developed by ten participants of the Task Force. Blind validation of the wind loads from CFD simulations has been made for a semisubmersible with simplified topsides geometry. Comparison of the wind loads from independent CFD simulations from the participants confirmed that CFD can provide reliable and accurate wind load with fewer uncertainties in the simulation (or test) set up than wind-tunnel testing. A roadmap to develop the guidelines based on the CFD modeling practices is proposed.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79501493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Zhao, Sylvain Chambon, Yuelin Shen, Sai Venkatakrishnan, M. Hamzah
The drilling process can be broken down into various activities from top-level activities (e.g., drilling and tripping) to lower-level activities (e.g., in-slip, out-of-slip, making connection, and circulation). The detection of the fundamental drilling unit, a stand, is necessary and essential for recognizing and inferring drilling activities. A new method is proposed to detect slip status, pipe change, and drilling/tripping stands based on real-time streaming data. The slip status is a critical element because it indicates a connection is made before drilling or tripping a stand. The proposed method is designed to infer the slip status with hookload, standpipe pressure (SPPA), and surface torque (STOR) sensor data. Specifically, the logic using hookload includes two criteria, a hookload standard deviation criterion and a dynamic hookload threshold criterion. This allows addressing the limitations of prior methods at shallow depth and using a manual threshold, which prevents the full automation of slip detection. In addition, the slip status can be confirmed or corrected with a logic using a combination of SPPA and STOR data. Then, a check is performed on whether a stand is added or removed during in-slip period. If needed, the stand detection can also be run to detect where a stand begins and ends. The method has been extensively tested and validated on many land and deepwater wells with drilling/tripping operations. Without human intervention, the dynamic hookload threshold can be determined automatically and adaptively after one or two drilling or tripping stands. Moreover, the hookload standard deviation criterion works well to detect the change of slip status at shallow depth. It is shown that high accuracy of detection can be achieved when the streaming data have a proper range of sampling rate. The new method addresses two limitations of the existing methods: (1) it automatically determines the dynamic hookload thresholds and eliminates the need of setting up the hookload threshold manually, and (2) it improves the accuracy of slip status and stand detection at shallow depth. This innovative work enables the automation of the slip status and stand detection process in batch runs or in real time without operator input.
{"title":"Automatic Slip Status and Stand Detection in Real-Time Drilling","authors":"Jie Zhao, Sylvain Chambon, Yuelin Shen, Sai Venkatakrishnan, M. Hamzah","doi":"10.4043/29372-MS","DOIUrl":"https://doi.org/10.4043/29372-MS","url":null,"abstract":"\u0000 The drilling process can be broken down into various activities from top-level activities (e.g., drilling and tripping) to lower-level activities (e.g., in-slip, out-of-slip, making connection, and circulation). The detection of the fundamental drilling unit, a stand, is necessary and essential for recognizing and inferring drilling activities. A new method is proposed to detect slip status, pipe change, and drilling/tripping stands based on real-time streaming data.\u0000 The slip status is a critical element because it indicates a connection is made before drilling or tripping a stand. The proposed method is designed to infer the slip status with hookload, standpipe pressure (SPPA), and surface torque (STOR) sensor data. Specifically, the logic using hookload includes two criteria, a hookload standard deviation criterion and a dynamic hookload threshold criterion. This allows addressing the limitations of prior methods at shallow depth and using a manual threshold, which prevents the full automation of slip detection. In addition, the slip status can be confirmed or corrected with a logic using a combination of SPPA and STOR data. Then, a check is performed on whether a stand is added or removed during in-slip period. If needed, the stand detection can also be run to detect where a stand begins and ends.\u0000 The method has been extensively tested and validated on many land and deepwater wells with drilling/tripping operations. Without human intervention, the dynamic hookload threshold can be determined automatically and adaptively after one or two drilling or tripping stands. Moreover, the hookload standard deviation criterion works well to detect the change of slip status at shallow depth. It is shown that high accuracy of detection can be achieved when the streaming data have a proper range of sampling rate.\u0000 The new method addresses two limitations of the existing methods: (1) it automatically determines the dynamic hookload thresholds and eliminates the need of setting up the hookload threshold manually, and (2) it improves the accuracy of slip status and stand detection at shallow depth. This innovative work enables the automation of the slip status and stand detection process in batch runs or in real time without operator input.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90852646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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