Atlanta Field is a post-salt heavy oilfield located 185 km off the city of Rio de Janeiro, in Santos Basin, Brazil, at a water depth of approximately 1,550 m. Atlanta, however, is not just another ultra-deepwater heavy oil field. Several additional challenges had to be overcome for its development, such as: (i) low reservoir overburden (800 m); (ii) highly unconsolidated sandstone reservoir (36% porosity and 5,000 mD permeability); (iii) heavy and viscous crude flow assurance (14°API and 228 cP at initial reservoir conditions); (iv) high naphthenic acidity oil (TAN 10 mg KOH/g); (v) high power artificial lift pumping system requirement (1,600 hp); and (vi) complex topside crude facilities. The development of Atlanta Field was phased in two stages: (i) an Early Production System (EPS), which is expected to last from four to five years and comprises three horizontal production wells, and (ii) a Definitive Production System (DPS), which will add nine wells to complete the development plan with 12 horizontal producers. The first two EPS wells were successfully constructed and tested during 2013 and 2014, proving the feasibility of surpassing the great challenges imposed by the field’s unique environment and enabling the beginning of the production phase of the field. First oil occurred in May 2018 with these two wells producing to the FPSO Petrojarl I. The third and last producer of the EPS was constructed in 2019 and began operation in June of the same year. More than five million barrels of oil were already produced to date. Marsili et al. (2015) described in detail the exploration and development phases of Atlanta focusing on their challenges and the overcoming process and solutions adopted. This current work intends to present an updated review of the paper, providing the most recent information related to the project with a subsequent focus on the production phase findings and results. Among others, initial prediction and expectations will be compared with actual field performance. For all milestones achieved, Atlanta project is considered a great success so far and a benchmark for the industry in this harsh and adverse environment.
{"title":"Atlanta Field: Producing Heavy and Viscous Oil in Ultra-Deepwater","authors":"M. Marsili, P. Rocha, Igor de Almeida Ferreira","doi":"10.4043/29721-ms","DOIUrl":"https://doi.org/10.4043/29721-ms","url":null,"abstract":"\u0000 Atlanta Field is a post-salt heavy oilfield located 185 km off the city of Rio de Janeiro, in Santos Basin, Brazil, at a water depth of approximately 1,550 m. Atlanta, however, is not just another ultra-deepwater heavy oil field. Several additional challenges had to be overcome for its development, such as: (i) low reservoir overburden (800 m); (ii) highly unconsolidated sandstone reservoir (36% porosity and 5,000 mD permeability); (iii) heavy and viscous crude flow assurance (14°API and 228 cP at initial reservoir conditions); (iv) high naphthenic acidity oil (TAN 10 mg KOH/g); (v) high power artificial lift pumping system requirement (1,600 hp); and (vi) complex topside crude facilities.\u0000 The development of Atlanta Field was phased in two stages: (i) an Early Production System (EPS), which is expected to last from four to five years and comprises three horizontal production wells, and (ii) a Definitive Production System (DPS), which will add nine wells to complete the development plan with 12 horizontal producers. The first two EPS wells were successfully constructed and tested during 2013 and 2014, proving the feasibility of surpassing the great challenges imposed by the field’s unique environment and enabling the beginning of the production phase of the field. First oil occurred in May 2018 with these two wells producing to the FPSO Petrojarl I. The third and last producer of the EPS was constructed in 2019 and began operation in June of the same year. More than five million barrels of oil were already produced to date.\u0000 Marsili et al. (2015) described in detail the exploration and development phases of Atlanta focusing on their challenges and the overcoming process and solutions adopted. This current work intends to present an updated review of the paper, providing the most recent information related to the project with a subsequent focus on the production phase findings and results. Among others, initial prediction and expectations will be compared with actual field performance. For all milestones achieved, Atlanta project is considered a great success so far and a benchmark for the industry in this harsh and adverse environment.","PeriodicalId":415055,"journal":{"name":"Day 1 Tue, October 29, 2019","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128506275","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}
C. Pedroso, J. Salies, R. Aguiar, Daniel G Lemos, Rafael Kenupp, P. Oliveira, W. A. Costa, Robson Soares, C. Cova, A. Tocchetto, Bruno Simoes, M. Nunes
Atlanta is a post-salt oil field located offshore Brazil in the Santos Basin, 150 km southeast of Rio de Janeiro. The combination of ultra-deep water (1550m), heavy and viscous oil (14 API), unconsolidated sandstones, low overburden (800m), faulted reservoir rock, etc., composes a unique and challenging scenario for which the remarkable solutions applied have been already detailed (Marsili et al. 2015; Pedroso et al. 2017; Monteiro et al. 2015; Pedroso et al. 2015; Rausis et al. 2015; Pedroso et al. 2015). The Atlanta field project was planned to be developed in two phases: the Early Production System (EPS) with three production wells, and the Definitive Production System (DPS) with up to nine wells. No injection wells have been planned. In 2013 and 2014 the first two wells, here called ATL-2 and ATL-3 (ATL-1 was a pilot well), were successfully drilled, completed, and tested as described in the above references. In May 2018, they started production. After almost one year and 5,000,000 bbl of produced oil, the third EPS well was constructed. The lessons learned in each phase of the well construction - drilling, lower completion, and upper completion - were applied in the third well, repeating the good operational performance. An analysis of this comparative performance is presented. Technology improvements were implemented, such as the use of autonomous inflow control devices (AICD), the use of micro-tortuosity logging to better position the electrical submersible pump (ESP), the use of an annulus diverter valve (ADV) to avoid the pressure drop across the ESP in case of failure, etc. The result was a well constructed ahead the planned time with a Productivity Index (PI) that exceeded expectations.
亚特兰大是一个盐后油田，位于巴西近海桑托斯盆地，里约热内卢东南150公里处。超深水(1550m)、稠油和稠油(14api)、松散砂岩、低覆盖层(800m)、断层储层岩石等组合构成了一个独特而具有挑战性的场景，已经详细介绍了应用的卓越解决方案(Marsili et al. 2015;Pedroso et al. 2017;Monteiro et al. 2015;Pedroso et al. 2015;Rausis et al. 2015;Pedroso et al. 2015)。亚特兰大油田项目计划分两个阶段进行开发:包括3口生产井的早期生产系统(EPS)和多达9口井的最终生产系统(DPS)。没有计划注入井。2013年和2014年，前两口井ATL-2和ATL-3 (ATL-1为试验井)成功钻完井并进行了测试。2018年5月，它们开始生产。经过近一年的开采，生产了500万桶石油，第三口EPS井建成。在钻井、下完井和上完井的各个阶段吸取的经验教训被应用到第三口井中，重复了良好的作业效果。本文对这种比较性能进行了分析。随后进行了技术改进，例如使用自主流入控制装置(AICD)，使用微弯曲度测井来更好地定位电潜泵(ESP)，使用环空分流阀(ADV)来避免ESP发生故障时的压降等。结果是在计划时间之前构建了一口井，其生产力指数(PI)超出了预期。
{"title":"Atlanta Field: Constructing Long Horizontal Wells in a Challenging Environment","authors":"C. Pedroso, J. Salies, R. Aguiar, Daniel G Lemos, Rafael Kenupp, P. Oliveira, W. A. Costa, Robson Soares, C. Cova, A. Tocchetto, Bruno Simoes, M. Nunes","doi":"10.4043/29757-ms","DOIUrl":"https://doi.org/10.4043/29757-ms","url":null,"abstract":"\u0000 Atlanta is a post-salt oil field located offshore Brazil in the Santos Basin, 150 km southeast of Rio de Janeiro. The combination of ultra-deep water (1550m), heavy and viscous oil (14 API), unconsolidated sandstones, low overburden (800m), faulted reservoir rock, etc., composes a unique and challenging scenario for which the remarkable solutions applied have been already detailed (Marsili et al. 2015; Pedroso et al. 2017; Monteiro et al. 2015; Pedroso et al. 2015; Rausis et al. 2015; Pedroso et al. 2015).\u0000 The Atlanta field project was planned to be developed in two phases: the Early Production System (EPS) with three production wells, and the Definitive Production System (DPS) with up to nine wells. No injection wells have been planned.\u0000 In 2013 and 2014 the first two wells, here called ATL-2 and ATL-3 (ATL-1 was a pilot well), were successfully drilled, completed, and tested as described in the above references. In May 2018, they started production. After almost one year and 5,000,000 bbl of produced oil, the third EPS well was constructed.\u0000 The lessons learned in each phase of the well construction - drilling, lower completion, and upper completion - were applied in the third well, repeating the good operational performance. An analysis of this comparative performance is presented.\u0000 Technology improvements were implemented, such as the use of autonomous inflow control devices (AICD), the use of micro-tortuosity logging to better position the electrical submersible pump (ESP), the use of an annulus diverter valve (ADV) to avoid the pressure drop across the ESP in case of failure, etc.\u0000 The result was a well constructed ahead the planned time with a Productivity Index (PI) that exceeded expectations.","PeriodicalId":415055,"journal":{"name":"Day 1 Tue, October 29, 2019","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128507652","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}
A new analytical approach is applied to the riser's equations of motion, aimed at the real-time processing of solutions under hard boundary conditions. Based on this, a mathematical framework is devised, with the objective of supplying practical assistance for challenging riser positioning cases, leading to both live visualizations of the riser displacement during its maneuvering and on-the-fly planning of its desired top-end movement. The new analytical solution is based on a non-causal analysis using the two-sided Laplace Transform. By transforming a set of approximate PDEs that closely resemble those of the complete riser model, we're able to devise improper transfer functions between any two arbitrary points across the riser. Then, an inverse transformation applied to these transfer functions yields convolutions that may be quickly processed. Nonlinear boundary conditions are dealt with via a proposed iterative method. Quickly computable simulations for the horizontal displacement along the riser's length are presented, allowing for live, simultaneous estimation of the structure's motion at various cross-sections. Likewise, stress/tension estimates at these points are presented in real time. Furthermore, various top-end trajectories and motion strategies are derived for scenarios previously unsolved in the literature, involving non-static initial conditions, disturbances and time-variable tensions acting on the bottom-end of the riser. This is done to demonstrate the theory's applicability in dire weather conditions. Finally, the proposed solution is validated and compared to previous results in modeling and trajectory planning of risers. The speed of the presented approach is attested and properly analyzed.
{"title":"Real-Time Simulation and Motion-Planning for Riser-Based Drilling and Equipment Positioning","authors":"A. Bizzi, E. Fortaleza, Marcio Yamamoto","doi":"10.4043/29719-ms","DOIUrl":"https://doi.org/10.4043/29719-ms","url":null,"abstract":"\u0000 A new analytical approach is applied to the riser's equations of motion, aimed at the real-time processing of solutions under hard boundary conditions. Based on this, a mathematical framework is devised, with the objective of supplying practical assistance for challenging riser positioning cases, leading to both live visualizations of the riser displacement during its maneuvering and on-the-fly planning of its desired top-end movement.\u0000 The new analytical solution is based on a non-causal analysis using the two-sided Laplace Transform. By transforming a set of approximate PDEs that closely resemble those of the complete riser model, we're able to devise improper transfer functions between any two arbitrary points across the riser. Then, an inverse transformation applied to these transfer functions yields convolutions that may be quickly processed. Nonlinear boundary conditions are dealt with via a proposed iterative method.\u0000 Quickly computable simulations for the horizontal displacement along the riser's length are presented, allowing for live, simultaneous estimation of the structure's motion at various cross-sections. Likewise, stress/tension estimates at these points are presented in real time.\u0000 Furthermore, various top-end trajectories and motion strategies are derived for scenarios previously unsolved in the literature, involving non-static initial conditions, disturbances and time-variable tensions acting on the bottom-end of the riser. This is done to demonstrate the theory's applicability in dire weather conditions.\u0000 Finally, the proposed solution is validated and compared to previous results in modeling and trajectory planning of risers. The speed of the presented approach is attested and properly analyzed.","PeriodicalId":415055,"journal":{"name":"Day 1 Tue, October 29, 2019","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127179359","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}
Over the last 50 years, the oil & gas industry has continually pushed the limits of exploration, riding the wave of recent technological advances to pioneer ultra-deepwater areas of the globe. Not until the early 80s, though, did operators start delving below the salt canopy, into reserves like the Wilcox in the Gulf of Mexico. This sub-salt (or pre-salt) trend expanded well program depths in excess of 30,000 ft MD, in water depths exceeding 10,000 ft, necessitating longer, heavier casing/landing strings. Meanwhile, new government regulations have begun mandating well designs capable of sustaining Worst Case Discharge (WCD). Deeper casing strings, in turn, must now be constructed to withstand higher collapse loads, shallow casing strings to handle more robust burst loads. Certain well designs must even feature an intermediate tieback able to endure WCD, where previously a nested liner was sufficient. This confluence of increasingly deep wells and stringent regulations presents challenges. Longer, heavier casing/landing strings push the limits of existing tubular tensile capacity, but as important, they also raise concerns about handling equipment possibly crushing landing strings due to excessive radial load (slip crush). In response, since the mid-80s, a research and testing program has been analyzing and quantifying specific factors involved when crushing loads affect tubular goods failure. Some of the identified causatives behind these increased tubular stresses are handling equipment design, vessel heave-induced dynamic loading, dynamic loading during tripping, and handling equipment-related slip crush loading. A detailed analysis of the mechanics of slip crush revealed modifying certain parameters has a material effect on the radial load imparted onto the pipe by the slips. The research shows that modifying and optimizing the combination of these parameters can not only lead to the design of handling equipment with higher slip crush capacities, but it also leads to the development of a comprehensive model that can more accurately predict the failure of tubular goods due to slip crush.
在过去的50年里，石油和天然气行业一直在推动勘探的极限，乘着最近技术进步的浪潮，开拓全球超深水区域。然而，直到20世纪80年代初，运营商才开始深入到盐层下面，进入墨西哥湾的威尔科克斯等储量。这种盐下(或盐下)趋势将井的深度扩展到超过30,000 ft MD，在水深超过10,000 ft的情况下，需要更长、更重的套管/下放管柱。与此同时，新的政府法规开始要求油井设计能够承受最坏情况排放(WCD)。更深的套管柱必须能够承受更高的坍塌载荷，而浅的套管柱则必须能够承受更强的爆裂载荷。某些井的设计甚至必须采用能够承受WCD的中间回接，而以前嵌套尾管就足够了。越来越深的井和严格的法规的结合带来了挑战。更长、更重的套管/着陆管柱将现有管柱的抗拉能力推到了极限，但同样重要的是，它们也引起了人们的担忧，即由于过度的径向载荷(滑动挤压)，搬运设备可能会压碎着陆管柱。因此，自80年代中期以来，一项研究和测试计划一直在分析和量化破碎载荷影响管状货物失效时涉及的具体因素。造成管状压力增加的原因包括处理设备的设计、船舶起下钻时的动载荷、起下钻时的动载荷以及处理设备相关的滑压载荷。对卡瓦挤压力学的详细分析表明，改变某些参数会对卡瓦传递给管道的径向载荷产生实质性影响。研究表明，对这些参数的组合进行修改和优化，不仅可以设计出具有更高打滑破碎能力的搬运设备，而且可以建立更准确地预测管状货物打滑破碎失效的综合模型。
{"title":"A Detailed Examination of the Mechanics of Slip Crush When Landing Heavy Casing Strings","authors":"Robert L. Thibodeaux","doi":"10.4043/29761-ms","DOIUrl":"https://doi.org/10.4043/29761-ms","url":null,"abstract":"\u0000 Over the last 50 years, the oil & gas industry has continually pushed the limits of exploration, riding the wave of recent technological advances to pioneer ultra-deepwater areas of the globe. Not until the early 80s, though, did operators start delving below the salt canopy, into reserves like the Wilcox in the Gulf of Mexico. This sub-salt (or pre-salt) trend expanded well program depths in excess of 30,000 ft MD, in water depths exceeding 10,000 ft, necessitating longer, heavier casing/landing strings.\u0000 Meanwhile, new government regulations have begun mandating well designs capable of sustaining Worst Case Discharge (WCD). Deeper casing strings, in turn, must now be constructed to withstand higher collapse loads, shallow casing strings to handle more robust burst loads. Certain well designs must even feature an intermediate tieback able to endure WCD, where previously a nested liner was sufficient.\u0000 This confluence of increasingly deep wells and stringent regulations presents challenges. Longer, heavier casing/landing strings push the limits of existing tubular tensile capacity, but as important, they also raise concerns about handling equipment possibly crushing landing strings due to excessive radial load (slip crush).\u0000 In response, since the mid-80s, a research and testing program has been analyzing and quantifying specific factors involved when crushing loads affect tubular goods failure. Some of the identified causatives behind these increased tubular stresses are handling equipment design, vessel heave-induced dynamic loading, dynamic loading during tripping, and handling equipment-related slip crush loading. A detailed analysis of the mechanics of slip crush revealed modifying certain parameters has a material effect on the radial load imparted onto the pipe by the slips. The research shows that modifying and optimizing the combination of these parameters can not only lead to the design of handling equipment with higher slip crush capacities, but it also leads to the development of a comprehensive model that can more accurately predict the failure of tubular goods due to slip crush.","PeriodicalId":415055,"journal":{"name":"Day 1 Tue, October 29, 2019","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126645487","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}
Zhaojie Song, Yilei Song, Yuzhen Li, B. Bai, Kaoping Song, J. Hou
Primary oil recovery remains less than 10% in tight oil reservoirs, even after expensive multistage horizontal well hydraulic fracturing stimulation. Substantial experiments and pilot tests have been performed to investigate CO2-EOR potential in tight reservoirs; however, some results conflict with each other. The objective of this paper is to diagnose how these conflicting results occurred and to identify a way to narrow the gap between experimental results and field performance through a comprehensive literature review and data analysis. Peer-reviewed journal papers, technical reports, and SPE publications were collected, and three key steps were taken to reach our goal. First, rock and fluid properties of tight reservoirs in North America and China were compared, and their potential effect on tight oil production was analyzed. Afterward, based on published experimental studies and simulation works, the CO2-EOR mechanisms were discussed, including molecular diffusion, CO2-oil interaction considering nanopore confinement, and CO2-fluid-rock minerals interaction. Subsequently, pilot projects were examined to understand the gap between laboratory works and field tests, and the challenges faced in China's tight oil exploitation were rigorously analyzed. Compared with Bakken and Eagle Ford formation, China's tight oil reservoirs feature higher mud content and oil viscosity while they have a lower brittleness index and formation pressure, leading to confined stimulated reservoir volume and further limited CO2-oil contact. The effect of CO2 molecular diffusion was relatively exaggerated in experimental results, which could be attributed to the dual restrictions of exposure time and oil-CO2 area in field scale. Numerical modeling showed that the improved phase properties in nanopores led to enhanced oil recovery. The development of nano-scale chips withholding high pressure/temperature may advance the experimental study on nano-confinement's effect. Oil recovery can be further enhanced through wettability alteration due to CO2 adsorption on nanopores and reaction with rock minerals. CO2 huff-n-puff operations were more commonly applied in North America than China, and the huff time is in the order of 10 days, but the soaking time is less. Conformance control was essential during CO2 flooding in order to delay gas breakthrough and promote CO2-oil interaction. There is less than 5% of tight oil reserve surrounded by CO2 reservoirs in China, limiting the application of CO2-EOR technologies. An economic incentive from the government is necessary to consider the application of CO2 from power plants, refineries, etc. This work provides an explanation of conflicting results from different research methods and pilot tests, and helps researchers and oil operators understand where and when the CO2-EOR can be best applied in unconventional reservoirs. New directions for future work on CO2-EOR in tight formations are also recommended.
{"title":"A Critical Review of CO2 Enhanced Oil Recovery in Tight Oil Reservoirs of North America and China","authors":"Zhaojie Song, Yilei Song, Yuzhen Li, B. Bai, Kaoping Song, J. Hou","doi":"10.2118/196548-ms","DOIUrl":"https://doi.org/10.2118/196548-ms","url":null,"abstract":"\u0000 Primary oil recovery remains less than 10% in tight oil reservoirs, even after expensive multistage horizontal well hydraulic fracturing stimulation. Substantial experiments and pilot tests have been performed to investigate CO2-EOR potential in tight reservoirs; however, some results conflict with each other. The objective of this paper is to diagnose how these conflicting results occurred and to identify a way to narrow the gap between experimental results and field performance through a comprehensive literature review and data analysis.\u0000 Peer-reviewed journal papers, technical reports, and SPE publications were collected, and three key steps were taken to reach our goal. First, rock and fluid properties of tight reservoirs in North America and China were compared, and their potential effect on tight oil production was analyzed. Afterward, based on published experimental studies and simulation works, the CO2-EOR mechanisms were discussed, including molecular diffusion, CO2-oil interaction considering nanopore confinement, and CO2-fluid-rock minerals interaction. Subsequently, pilot projects were examined to understand the gap between laboratory works and field tests, and the challenges faced in China's tight oil exploitation were rigorously analyzed.\u0000 Compared with Bakken and Eagle Ford formation, China's tight oil reservoirs feature higher mud content and oil viscosity while they have a lower brittleness index and formation pressure, leading to confined stimulated reservoir volume and further limited CO2-oil contact. The effect of CO2 molecular diffusion was relatively exaggerated in experimental results, which could be attributed to the dual restrictions of exposure time and oil-CO2 area in field scale. Numerical modeling showed that the improved phase properties in nanopores led to enhanced oil recovery. The development of nano-scale chips withholding high pressure/temperature may advance the experimental study on nano-confinement's effect. Oil recovery can be further enhanced through wettability alteration due to CO2 adsorption on nanopores and reaction with rock minerals. CO2 huff-n-puff operations were more commonly applied in North America than China, and the huff time is in the order of 10 days, but the soaking time is less. Conformance control was essential during CO2 flooding in order to delay gas breakthrough and promote CO2-oil interaction. There is less than 5% of tight oil reserve surrounded by CO2 reservoirs in China, limiting the application of CO2-EOR technologies. An economic incentive from the government is necessary to consider the application of CO2 from power plants, refineries, etc.\u0000 This work provides an explanation of conflicting results from different research methods and pilot tests, and helps researchers and oil operators understand where and when the CO2-EOR can be best applied in unconventional reservoirs. New directions for future work on CO2-EOR in tight formations are also recommended.","PeriodicalId":415055,"journal":{"name":"Day 1 Tue, October 29, 2019","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127912998","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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