Day 2 Tue, August 17, 2021最新文献

{"title":"Modeling Production Facilities Using Conventional Process Simulators and Data Validation and Reconciliation DVR Methodology","authors":"Tom D. Mooney, Kelda Bratley, A. Amin, Timothy Jadot","doi":"10.4043/31082-ms","DOIUrl":"https://doi.org/10.4043/31082-ms","url":null,"abstract":"\u0000 The use of conventional process simulators is commonplace for system design and is growing in use for online monitoring and optimization applications. While these simulators are extremely useful, additional value can be extracted by combining simulator predictions with field inputs from measurement devices such as flowmeters, pressure and temperature sensors. The statistical nature of inputs (e.g., measurement uncertainty) are typically not considered in the forward calculations performed by the simulators and so may lead to erroneous results if the actual raw measurement is in error or biased.\u0000 A complementary modeling methodology is proposed to identify and correct measurement and process errors as an integral part of a robust simulation practice. The studied approach ensures best quality data for direct use in the process models and simulators for operations and process surveillance. From a design perspective, this approach also makes it possible to evaluate the impact of uncertainty of measured and unmeasured variables on CAPEX spend and optimize instrument / meter design.\u0000 In this work, an extended statistical approach to process simulation is examined using Data Validation and Reconciliation, (DVR). The DVR methodology is compared to conventional non-statistical, deterministic process simulators. A key difference is that DVR uses any measured variable (inlet, outlet, or in between measurements), including its uncertainty, in the modelled process as an input, where only inlet measurement values are used by traditional simulators to estimate the values of all other measured and unmeasured variables.\u0000 A walk through the DVR calculations and applications is done using several comparative case studies of a typical surface process facility. Examples are the simulation of commingled multistage oil and gas separation process, the validation of separators flowmeters and fluids samples, and the quantification of unmeasured variables along with their uncertainties. The studies demonstrate the added value from using redundancy from all available measurements in a process model based on the DVR method.\u0000 Single points and data streaming field cases highlight the dependency and complementing roles of traditional simulators, and data validation provided by the DVR methodology; it is shown how robust measurement management strategies can be developed based on DVR’s effective surveillance capabilities. Moreover, the cases demonstrate how DVR-based capex and opex improvements are derived from effective hardware selection using cost versus measurement precision trade-offs, soft measurements substitutes, and from condition-based maintenance strategies.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83837192","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}

{"title":"Cable JIP: A Research Project to Assess the Feasibility of a Semi-Static Electrical Subsea Cable for the Power Take-off from a TLP-type Floating Offshore Wind Turbine","authors":"J. D. Wilde, C. V. D. Nat, L.. Pots, L. Vries, Q. Liu","doi":"10.4043/31209-ms","DOIUrl":"https://doi.org/10.4043/31209-ms","url":null,"abstract":"\u0000 CABLE JIP research project in 2017-2019 was initiated with the aim of studying the feasibility of deploying a novel semi-static electrical cable for the power take-off from a TLP-type Floating Offshore Wind Turbine (FOWT). Today, expensive dynamic electrical cables are mainly used for the power take-off from demonstrator project FOWTs or from new FOWTs on the drawing board. For a TLP-type FOWT, the use of a semi-static electrical power cable instead of a fully dynamic electrical power cable (umbilical) is an attractive option to reduce the levelized cost of energy (LCoE). However, the electrical power cable in a dynamic offshore environment is vulnerable to failure, either at the floater side or at the seabed touchdown area. Moreover, the electrical power cable for power take-off is typically non-redundant, while the availability of the turbine(s) highly depends on this critical component to transport the produced power to the substation. The paper discusses the results of the CABLE JIP research project, with focus on the verification and calibration of the numerical models for the ULS and FLS assessment of the electrical power inter-array cable for a harsh weather test case with a TLP-type floating offshore wind turbine in 96.5 m water depth.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74650447","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}

{"title":"First Time Utilization of Cloud-Based Technology to Fast Track A 521 Million Cell Gas Condensate Reservoir Dynamic Model: A Case Study from Saudi Arabia","authors":"A. Al-Fawwaz, Yousif M. Al-Dhafiri, M. N. Akhtar, Samad Ali, Muhammad Ibrahim, M. Giddins, A. Amer","doi":"10.4043/31194-ms","DOIUrl":"https://doi.org/10.4043/31194-ms","url":null,"abstract":"\u0000 The main objective of this study is to run a high-resolution dynamic simulation on a 521-million cell gas condensate field model for 50 years and capture the effects of gas condensate dropout. Two challenges were encountered on the user and service provider levels. The former is performing such work in a remote location with limited processing hardware resources. The latter is related to resolving memory, CPU allocation, technical support, system resources availability, integration between providers, and simulation needs on user demand.\u0000 The approach adopted in this field development planning study was to utilize the latest cloud technology to run the 521 million cell simulation on cloud clusters as well as two upscaled versions (5 and 21 million cells). Such procedures can save significant processing time and money. As opposed to direct purchase and installation of clusters that require maintenance, updates, and become outdated over time, with a cloud cluster that is kept updated and maintained by service providers, significant cost overheads (in millions) could be saved. Using such technology allows operators to get global technical support making executing such simulations viable even in the most remote locations.\u0000 The field under study is a gas condensate field that on its own can present multiple challenges including the gas condensate banking impact and compositional modeling. The main strategy adopted in this study was to utilize the static model with no upscaling, to capture the geological details. With the utilization of cloud technology, all simulations were completed in record time. The 5 million cell model was executed in 23 min, while the 21 million cell model executed in 4 hours, and the 521 million executed in 65 hours. The results of the simulations showed that the gas condensate banking effect was captured clearly after the implementation of local grid refinement (LGR) on the upscaled models. A good match was observed in the production profiles for all key parameters, such as gas rates, oil and condensate rates and their cumulative productions.\u0000 Using cloud technology saved the operating company over 5 million dollars in cluster hardware direct purchase, support and maintenance costs, making the utilization of the cloud computing technology not only economical, but also bringing about operational efficiencies.\u0000 This is the first time a cloud-based dynamic simulation is performed on a 521 million cell model in the world and the first time, an on-demand reservoir simulation based on cloud computing technology has been conducted in the Middle East region. This paper will also show that, given the right model parameters, carefully built smaller models can yield results similar to larger models, highlighting the importance of efficiency.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79469463","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}

{"title":"Highly Efficient Renewal of A Hydropower Plant Pipe Coating","authors":"P. Palatka","doi":"10.4043/30997-ms","DOIUrl":"https://doi.org/10.4043/30997-ms","url":null,"abstract":"Many pumped storage hydropower plants have long large diameter steep steel pipes (penstocks) between reservoirs. The coating inside such pipes protects the surface from corrosion. Lifetime of the coating is limited and it has to be renewed several times during expected lifetime of the hydropower plant. The coating renovation was a manual process until now. A modification of the process is proposed. The modification of the process includes changes in the technological steps as well robotization of these steps. The new process provides more stability in the quality of coating and eliminates unnecessary presence of people in confined spaces. Using a robot also makes the renewal of the coating much faster. Therefore, it can bring a lot of profit to the owner by shortening the production downtime and re-starting production significantly earlier in comparison to the existing renovation process.\u0000 The new process was verified in a pilot project at a selected pumped storage hydropower plant and the results were evaluated in cooperation with the hydropower plant owner. Laboratory tests of samples have shown that the coating has two times higher adhesion to the substrate in comparison to the manual coating application. The results also showed that the owner can save around 600 days of downtime on each of both penstocks when using this new process. This is a clear economical advantage which each owner of the infrastructure can understand easily.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82070112","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}

{"title":"Fatigue Monitoring and Life Extension for Top Tensioned Production Riser Systems","authors":"B. Mercan, M. Campbell, Clay Thompson","doi":"10.4043/31259-ms","DOIUrl":"https://doi.org/10.4043/31259-ms","url":null,"abstract":"\u0000 Top tensioned production riser (TTR) systems are exposed to fatigue loading in deep water as a result of vessel motions and high currents. The accuracy of predictions of the in-place fatigue response, which is a key input for any life extension requests, is dependent on the operating condition during the life of field including fluid contents and top tension. One solution to reduce this uncertainty is to deploy a fatigue monitoring system to assure the long-term integrity and performance of these riser systems. This paper presents results from a recent TTR monitoring campaign and focuses on the impact of top tension variation on riser motion and fatigue response in the field.\u0000 Standalone and ROV deployable motion loggers offer a low cost and robust method of fatigue monitoring. The motion loggers are installed at discrete locations along the TTR to measure riser motions and then determine fatigue accumulations. During one of the recent monitoring campaigns, riser top tension was changed due to operational requirements, which in turn affected the riser fatigue response in the field.\u0000 Field data is collected from two periods for two TTRs. The top tension was adjusted between each campaign allowing the effect of tension on riser fatigue response to be better understood using field measurements. The resulting riser motions and fatigue accumulations will be presented to demonstrate the sensitivity to top tension and highlight the importance of maintaining good records during the field life.\u0000 Currently, there is no single guideline in the US that addresses TTR life-extension programs in detail. The results from this monitoring program are one step forward in better understanding system behavior of deep water TTRs and assessing the feasibility of an extended service life.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"2014 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87760499","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}

{"title":"Acquire Ocean Bottom Seismic Data and Time-Lapse Geochemistry Data Simultaneously to Identify Compartmentalization and Map Hydrocarbon Movement","authors":"R. Schrynemeeckers","doi":"10.4043/30975-ms","DOIUrl":"https://doi.org/10.4043/30975-ms","url":null,"abstract":"\u0000 Current offshore hydrocarbon detection methods employ vessels to collect cores along transects over structures defined by seismic imaging which are then analyzed by standard geochemical methods. Due to the cost of core collection, the sample density over these structures is often insufficient to map hydrocarbon accumulation boundaries.\u0000 Traditional offshore geochemical methods cannot define reservoir sweet spots (i.e. areas of enhanced porosity, pressure, or net pay thickness) or measure light oil or gas condensate in the C7 – C15 carbon range. Thus, conventional geochemical methods are limited in their ability to help optimize offshore field development production.\u0000 The capability to attach ultrasensitive geochemical modules to Ocean Bottom Seismic (OBS) nodes provides a new capability to the industry which allows these modules to be deployed in very dense grid patterns that provide extensive coverage both on structure and off structure. Thus, both high resolution seismic data and high-resolution hydrocarbon data can be captured simultaneously.\u0000 Field trials were performed in offshore Ghana. The trial was not intended to duplicate normal field operations, but rather provide a pilot study to assess the viability of passive hydrocarbon modules to function properly in real world conditions in deep waters at elevated pressures. Water depth for the pilot survey ranged from 1500 – 1700 meters.\u0000 Positive thermogenic signatures were detected in the Gabon samples. A baseline (i.e. non-thermogenic) signature was also detected. The results indicated the positive signatures were thermogenic and could easily be differentiated from baseline or non-thermogenic signatures.\u0000 The ability to deploy geochemical modules with OBS nodes for reoccurring surveys in repetitive locations provides the ability to map the movement of hydrocarbons over time as well as discern depletion affects (i.e. time lapse geochemistry). The combined technologies will also be able to:\u0000 Identify compartmentalization, maximize production and profitability by mapping reservoir sweet spots (i.e. areas of higher porosity, pressure, & hydrocarbon richness), rank prospects, reduce risk by identifying poor prospectivity areas, accurately map hydrocarbon charge in pre-salt sequences, augment seismic data in highly thrusted and faulted areas.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89270020","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}

{"title":"Online Modeling of CO2 Storage Systems","authors":"D. D. Erickson, Gregory D. Metcalf","doi":"10.4043/31202-ms","DOIUrl":"https://doi.org/10.4043/31202-ms","url":null,"abstract":"\u0000 This paper discusses the development and deployment of a specialized online and offline integrated model to simulate the CO2 (Carbon Dioxide) Injection process. There is a very high level of CO2 in an LNG development and the CO2 must be removed in order to prepare the gas to be processed into LNG. To mitigate the global warming effects of this CO2, a large portion of the CO2 Rich Stream (98% purity) is injected back into a depleted oil field. To reduce costs, carbon steel flowlines are used but this introduces a risk of internal corrosion. The presence of free water increases the internal corrosion risk, and for this reason, a predictive model discussed in this paper is designed to help operations prevent free water dropout in the network in real time.\u0000 A flow management tool (FMT) is used to monitor the current state of the system and helps look at the impact of future events (startup, shutdowns etc.). The tool models the flow of the CO2 rich stream from the outlet of the compressor trains, through the network pipeline and manifolds and then into the injection wells. System behavior during steady state and transient operation is captured and analyzed to check water content and the balance of trace chemicals along with temperature and pressure throughout the network helping operators estimate corrosion rates and monitor the overall integrity of the system.\u0000 The system has been running online for 24/7 for 2 years. The model has been able to match events like startup/shutdown, cooldowns and blowdowns. During these events the prediction of temperature/pressure at several locations in the field matches measured data. The model is then able to forecasts events into the future to help operations plan how they will operate the field.\u0000 The tool uses a specialized thermodynamic model to predict the dropout of water in the near critical region of CO2 mixtures which includes various impurities. The model is designed to model startup and shutdown as the CO2 mixture moves across the phase boundary from liquid to gas or gas to liquid during these operations.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89341397","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}

{"title":"A New Era: Large Subsea Multiphase Compressor - Driven by Subsea Adjustable Speed Drive","authors":"H. Lendenmann, John Olav Fløisand, S. Vatland","doi":"10.4043/31192-ms","DOIUrl":"https://doi.org/10.4043/31192-ms","url":null,"abstract":"\u0000 The use of subsea processing equipment, which maintains, increases, and accelerates oil and gas production, is now more and more widespread in offshore subsea field developments. Furthermore, there is a strong drive for electrification of offshore fields, both subsea and topside, to lower emissions. To meet the technical challenges, a significant effort is put into research and technology development by academia and the industry. ABB, a specialist in electrical equipment and control systems, and OneSubsea, a specialist in subsea processing, have executed large development programs organized as Joint Industry Projects (JIPs) together with oil and gas operators. In this paper, we discuss how ABB and OneSubsea joined forces in testing and validating their respective subsea technologies as a full subsea system for subsea multiphase gas compression.\u0000 This paper presents the world's first full-scale, combined subsea adjustable speed drive (ASD) and multiphase compressor (WGC6000) string test. In spring of 2020, both the ASD, and the WGC6000 reached Technology Readiness Level 4. The string test, with both units concurrently submerged, completed its witness test program in June 2020, with mapping of the WGC6000 speed and power envelope and a subsequent 24 h thermal stability run. The flawless test result confirms the strategic development road map for all the involved partners.\u0000 The technologies presented in this paper are now fully qualified and available for commercial use enabling a paradigm shift in subsea oil and gas production.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81152255","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}

{"title":"Asset Lifecycle Management – The Digital Solution","authors":"Johnathan Eugene Dady","doi":"10.4043/31034-ms","DOIUrl":"https://doi.org/10.4043/31034-ms","url":null,"abstract":"\u0000 The challenges presented in the current market environment demand operational efficiency with low risk tolerance. Maximizing uptime and reducing unplanned events is paramount to preserve revenue. Asset Lifecycle Management (ALCM) is a strategy built to capitalize on the use of data analytics, superior system integration, and comprehensive condition assessments. This strategy is intended to produce significant benefits and maximize shareholder return through the optimization of maintenance, operations, and inventory.\u0000 Traditional schedules of maintaining equipment can be replaced with automated analytics enhanced by equipment design knowledge and historical data. Developing technology enables a cost-effective means of applying this capability. Monitoring equipment condition and advanced analysis of equipment data compared to design parameters and historical performance provides valuable insight into the actual usage and lifecycle of the equipment. Design life utilization (usage) of critical load path drilling equipment can be determined by comparing how much work the equipment has done to how much work it was designed to do. This paper explores new methods of analyzing operational and equipment data, enabling the creation of robust usage models. These models are compared with the analysis of vibration, oil, fatigue, dimensional, and other physical inspection data. This empowers a comprehensive usage and condition monitoring paradigm that is data driven. Case studies performed on multiple drilling rigs proves extremely low usage and supports the deferral of traditional 5-year overhauls on this equipment. Modeling of normal operations is also explored, and a hook load model is created. The statistical analysis available from this operating model is compared to historical operational and maintenance records and proves to track an actual failure, thus substantiating value for anomaly detection if used real-time.","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83587210","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}

{"title":"Design and Installation of Leading Edge, Practical and Economic Mooring Systems for Commercial Scale Floating Offshore Wind Energy","authors":"T. Fulton, Y. Arıkan, Regan Miller, Jonathan Kent Longridge, M. Campbell","doi":"10.4043/31318-ms","DOIUrl":"https://doi.org/10.4043/31318-ms","url":null,"abstract":"\u0000 \u0000 \u0000 As Floating Offshore Wind moves from demonstration and pilot projects to full commercial scale, there is a need for mooring systems to be practical and economic while providing safe and efficient stationkeeping for floating wind turbines. Mooring systems for floating offshore wind must be designed to meet the needs to provide a reliable stationkeeping system, satisfy turbine motions criteria for maximum energy production, accommodate electrical power transmission cables, allow for other marine users (e.g., fishing vessels, service vessels for inspections and maintenance, etc.) and be environmentally friendly. To be commercially viable, this must be done with an understanding of the need to moor 30 or more turbines in close proximity to one another with hundreds of mooring lines. To accomplish this, there is no one perfect mooring system for all projects. This paper will investigate multiple mooring solutions including various configurations and material types and will reveal both the technical and commercial benefits of the various systems.\u0000 \u0000 \u0000 \u0000 Multiple mooring systems will be designed to accommodate a 15 MW floating wind turbine. An installation methodology will be developed, and the supply chain will be investigated to enable calculation of the total installed cost of each system.\u0000 \u0000 \u0000 \u0000 The stationkeeping performance of each system will be compared as well as the economics for a large scale commercial floating wind farm. While no one system will be the clear best for all projects, guidance will be given which can aid in the selection of practical and economic mooring systems.\u0000 \u0000 \u0000 \u0000 The paper will investigate multiple viable mooring systems from the design, procurement, and installation viewpoint to develop total installed cost estimates. This will be done while evaluating these mooring systems for a large commercial size floating wind farm while addressing the need for the supply chain to deliver industrialized solutions to deal with the large scale.\u0000","PeriodicalId":10936,"journal":{"name":"Day 2 Tue, August 17, 2021","volume":"219 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76604189","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}