Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology最新文献

{"title":"Selecting the Best 3D Wellbore Trajectory Using a Fast Stiff Semi-Analytical 3D Torque and Drag Simulator","authors":"J. Sampaio, Ahmed K. Mansour","doi":"10.1115/omae2019-96385","DOIUrl":"https://doi.org/10.1115/omae2019-96385","url":null,"abstract":"\u0000 The process of designing a 3D wellbore trajectory, in general, takes into consideration only the expected initial and final coordinates, some “drillable” curvatures that can be delivered by the current technologies, and any of the various 3D planning models, each with a particular number of defining parameters. Some of the questions usually disregarded are: which model to take to design the trajectory, which values to take for the defining parameters, what to measure in the process of design, and what should be optimized. The objective of this work is to provide a systematic approach to 3D trajectory design based on torque and drag performance. For this purpose, it is unquestionable that the torque and the drag caused by the trajectory curvature, which are, considering all other variables the same, determined by the trajectory model and its parameters, dominate the discussion. Other things like trajectory length, borehole diameter, tubular good geometry, although influential, are irrelevant in the decision process because if they affect one model, they affect all others. Therefore, the use of an efficient, accurate, and general T&D model is of fundamental importance, and then we are left with the duty of measuring the adequate cost (or loss, or objective) function and optimizing this function. In this endeavor, a fast and accurate 3D stiff analytical T&D solution that allows analyzing a large number and wide range of parameters is of fundamental importance. Armed with such tool, and with the guidelines resulting from this work, the well designer can quickly determine the best trajectory and parameters that optimize the borehole construction and yet reaching the fundamental purpose of the well to be designed. Instead of requiring an extensive experience and/or creative (non-replicating) capacity of the well designer, the process delivers a systematic approach to trajectory design, based on the relevant objective parameters (e. g., minimum T&D, minimum equipment wear, reduced casing, cementing, hole cleaning and pipe sticking difficulties, and so far). To reach this goal a reasonable, but not thorough, understanding of the causes and effects of torque and drag is necessary in order to effectively play with the trajectory parameters. The causes and consequences of wellbore tortuosity is particularly discussed. In the process, several types of trajectory common in the industry are used and compared. To effectively compare the various models, it is assumed that all trajectories (based on the same initial and final conditions) have the same length (measured depth). This is not a necessary condition because different trajectory construction may require different amount of curvature control, which affects its cost. The T&D model itself is not covered because it has been discussed in another publication; however, a brief discussion is presented in the Annex 2. Any appropriate model serves the purpose although the requirement of being fast, accurate, 3D,","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114704865","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":"Optimizing Production Facilities Using a Transient Multiphase Flow Simulator","authors":"Abdulaziz Alqasim, Fahad Almudairis, Abdulrahman Bin Omar, A. Omair","doi":"10.1115/omae2019-95002","DOIUrl":"https://doi.org/10.1115/omae2019-95002","url":null,"abstract":"\u0000 This paper discusses a method for optimizing production facilities design for onshore/offshore wells during new field development. Optimizing the development of new oil and gas fields necessitates the use of accurate predication techniques to minimize uncertainties associated with day-to-day operational challenges related to wells, pipelines and surface facilities. It involves the use of a transient multiphase flow simulator (TMFS) for designing new oil and gas production systems to determine the feasibility of its economic development.\u0000 A synthetic offshore oil field that covers a wide range of subsurface and surface facility data is considered in this paper. 32 wells and two reservoirs are considered to evaluate the effect of varying sizes of tubing, wellhead choke, flowline, riser, and transport line. A detailed investigation of the scenario of emergency shutdowns to study its effect on the system is performed using TMFS. Other scenarios are also evaluated such as startup, depressurization, pigging, wax deposition, and hydrate formation.\u0000 This paper provides a method to minimize the cost by selecting the optimum pipelines sizes and diameters, and investigating the requirements of insulation, risk of pipeline corrosions and other related flow assurance parameters. Different facility design scenarios are considered using TMFS tool to achieve operational flexibility and eliminate associated risks. Pressure and temperature conditions are evaluated under several parametric scenarios to determine the best dimensions of the production system. This paper will also provide insight into factors affecting the flow assurance of oil and gas reservoirs.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132832067","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":"Additives to Enhance Cement Sheath Durability","authors":"M. Tabatabaei, A. D. Taleghani, N. Alem","doi":"10.1115/omae2019-96421","DOIUrl":"https://doi.org/10.1115/omae2019-96421","url":null,"abstract":"\u0000 The primary goal of the oil and gas well cementing is zonal isolation. During the production life of a well, the cement experiences various severe conditions affecting its permeability. These conditions include cracking, debonding, and shear failure which can be worsened by pressure fluctuations during hydraulic fracturing operations. Any of these conditions by forming micro-cracks within the cement or micro-annuli at the casing/cement or cement/rock interfaces create cement permeabilities far beyond the intrinsic permeability of the intact cement sheath. Recently, some studies have been devoted to improving the overall mechanical behavior of the cement by adding carbon nanotubes and carbon nano-fibers. Although these nano-additives offer considerably high strength and modulus, the high costs of these materials persuade us to find alternatives at relatively low costs, such as, graphite nanoplatelets (GNPs). Our preliminary laboratory studies show the effectiveness of GNPs in the enhancement of durability characteristics of the prepared nanocomposite cement paste by improving its compressive strength, ductility and toughness resistance. Considering the importance of dispersion of nanoadditives within the cementitious matrix, we physically or chemically manipulate the surface properties of GNPs to prevent the agglomeration of nanoparticles.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124622886","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":"Investigation of the Effect of Block Size, Shape and Freeze Bond Strength on Flexural Failure of Freshwater Ice Rubble Using the Discrete Element Method","authors":"S. Afzali, R. Taylor, E. Bailey, R. Sarracino, M. T. Boroojerdi","doi":"10.1115/omae2019-96722","DOIUrl":"https://doi.org/10.1115/omae2019-96722","url":null,"abstract":"\u0000 Understanding ice rubble strength and associated failure mechanics is important for a variety of engineering applications in marine ice environments, including the design and operation of coastal, offshore, subsea and floating structures. As part of the Mechanics of Ice Rubble project, recent experiments have been carried out to study the strength and failure behavior of ice rubble beams and the freeze bonds that form between individual ice blocks. These new results serve as an important guide for the development of improved numerical models. The discrete element method (DEM) is a direct modeling approach which has the potential to both describe and enhance understanding of the behavior of brittle granular materials, especially with regard to the evolution of damage towards failure. In this study we present results obtained from a newly developed model for the 3D DEM open-source code LIGGGHTS. The ice model contains normal and shear springs that operate between neighboring particles which are bonded or that overlap due to compressional stresses. Energy dissipation is accounted for by using a viscous damping model. Using this DEM model, medium-scale freshwater ice rubble punch tests have been simulated for ice rubble beams with nominal dimensions of 0.50m × 0.94m × 3.05m. Rubble specimens were generated by “raining” individual DEM ice pieces into a rectangular form and compacting the rubble mass to achieve the target porosity. Before the compacting pressure was removed, bonds between contacting blocks were introduced with parameter values chosen based on representative freeze bond experiments. The ice rubble beam was then deformed by pushing a platen vertically downward through the center of the beam until failure occurred. For the numerical simulations presented here, two types of block size and shapes have been considered: cuboid blocks generated based on the size distribution of the actual rubble, and rubble blocks generated by image processing of actual blocks of broken ice used in the comparison experiments. Results obtained for these two scenarios are compared with corresponding experimental test data. These results highlight that the DEM model is useful for estimating the flexural strength of the rubble, simulating the failure mechanism and for examining the extent to which the ice rubble beam failure is controlled by the strength of the freeze bonds. These results also provide valuable new insights regarding the importance of shape and size distribution of ice blocks on simulated ice rubble strength and failure behavior. Recommendations for future work are provided.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132880816","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":"Triaxial Testing of Gas Shale Permeability Dependence on Heterogeneous Stress With Respect to Bedding","authors":"Yufei Chen, Changbao Jiang, G. Yin, A. Wojtanowicz, Dongming Zhang","doi":"10.1115/omae2019-96707","DOIUrl":"https://doi.org/10.1115/omae2019-96707","url":null,"abstract":"\u0000 Shale gas has recently become the most promising source of unconventional hydrocarbon energy. Shale gas well deliverability and economics depend on extremely low permeability that is not only dependent on the rock bedding trend but is also controlled by in-situ stresses. Thus, prediction of well’s deliverability requires understanding permeability of a dipping shale with natural bedding under conditions of unequal stresses in-situ. The purpose of this study was to determine relative contributions of normal and tangential stresses with respect to the rock bedding plane on permeability evolution of Longmaxi shale in the Sichuan Basin, southwest China.\u0000 The study involved an analysis of the rock bedding structure, followed with triaxial testing of rock samples and theoretical modeling. We used SEM observation to identify existence of microfractures and numerous inter-particle pores along the shale bedding planes that provide dominant pathways for gas flow depending upon closing stress value. Stress-dependent permeability was tested with a newly-developed multi-functional true triaxial geophysical (TTG) apparatus providing for a steady state gas flow through the rock sample under conditions of normal stress and two unequal tangential stresses. Also simulated were the effects of stress-bedding and load cycling.\u0000 The results showed shale permeability reduction during the stress loading process and its gradual recovery during the unloading process for both normal and tangential stress loading cycles. A hysteresis of the permeability response to cyclic loading was the largest when normal stress cycling was dominant. Moreover, permeability change was more pronounced in response to normal stress but some effects of the tangential stresses were also observed — particularly when the tangential stresses were dominant. A theoretical model was derived to describe permeability change with effective stress in the presence of normal and tangential stresses. The model was empirically matched with the experimental results.\u0000 Assessment of relative contributions of normal and tangential stresses was quantified with the analysis of variance (ANOVA). The analysis revealed significance levels of normal stress, and two tangential stresses σt1 and σt2 on shale permeability as 81%, 5% and 14%, respectively, showing dominant effect of normal stress with clear contribution of tangential stresses. An almost 20-percent contribution of tangential stress loading to permeability response indicates a need for improvement in computing effective stress in permeability predictions of the Longmaxi shale. It also warrants testing other gas shales to specifically determine the effect.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115840894","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":"Robust Leakage Modeling for Plug and Abandonment Applications","authors":"M. Ramadan, S. Salehi, C. Teodoriu","doi":"10.1115/omae2019-95612","DOIUrl":"https://doi.org/10.1115/omae2019-95612","url":null,"abstract":"\u0000 Oil and gas wells that require to be shut off forever, after depleting their reserves, need to be plugged and abandoned. Plug and Abandonment (P&A) operations induce many arduous challenges worldwide. The aim of P&A is to isolate and prevent fluid leakage in the wellbore in such a way that all fluids are contained in their formation for an undefined time. Failure of P&A in isolating and preventing fluid leakage can jeopardize the well integrity. Cement plugs that are used in this operation play a crucial role in maintaining the well integrity.\u0000 Cement is considered as a porous medium that has an ultra-low permeability that can be achieved when some additives are used in the cement slurry to reduce its permeability and pore space. The cement plug may deteriorate with time under harsh downhole conditions, such as high pressure and temperature and exposure to different fluids. Cement plug deterioration will result in increasing the cement permeability or the overall permeability by creating channels or microannuli.\u0000 In this study, several scenarios are presented for gas leakage through cement plugs. In these leakage scenarios, the differential pressure across the cement plug was varied. The aim of generating these scenarios is to investigate the current required cement plug length. In each scenario, four different permeability values were used to assess the risk associated with each value. In addition, the cement plug length was varied to investigate how the cement plug length is going to help ensure good well integrity.\u0000 The leakage scenarios presented revealed that longer cement plugs have a longer leakage time. In addition, the results show an increase of leakage time as microannulus gap permeability decreases. Differential pressure exerted on the cement plug have a strong effect on the leakage time. To achieve a long term well integrity in P&A phase, an ultra-low permeable cement plug with excellent bonding, longer cement plug, and a lower differential pressure across the cement must be considered.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123900865","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 Voyage Planning Tool for Arctic Transit of Cargo Ships","authors":"Zhiyuan Li, J. Ringsberg, Francisco Rita","doi":"10.1115/OMAE2019-95128","DOIUrl":"https://doi.org/10.1115/OMAE2019-95128","url":null,"abstract":"\u0000 The paper presents a decision-support tool for maritime operations in Arctic seas. This tool targets at improving the safety and fuel efficiency of existing and future cargo vessels that are designed to operate in Arctic and in open water conditions. It is achieved by smart voyage planning using meteorological, oceanographic and ice forecasting.\u0000 A single-objective optimization for minimizing the fuel consumption in various scenarios of Arctic transits is established, with the transit time and the safety as the two major constraints. The tool is implemented in an in-house Matlab code, which is based on Dijkstra’s algorithm, a grid-based approach that aims at finding the most cost-efficient path connecting any chosen nodes in a given grid. Results from case studies along the Northern Sea Route indicate that the tool generates appropriate routes in ice-infested Arctic waters. The fuel consumption accounting for ice-induced extra resistance is optimized and the risk of collision with icebergs has been considered.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124561148","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":"Cement Plug Sealing Studies of Silica Cement Systems","authors":"A. Corina, N. Opedal, Torbjørn Vrålstad, S. Sangesland","doi":"10.1115/omae2019-95928","DOIUrl":"https://doi.org/10.1115/omae2019-95928","url":null,"abstract":"\u0000 A cement plug is widely applied for permanent abandonment phase to provide long-term zonal isolation against fluid flow. Maintaining cement plug integrity is a challenging task, and loss in cement sealing poses risks to the surrounding environment and surface safety. It is well-known that the cement performance is affected by cement material and downhole conditions. Nevertheless, investigations linking these influencing factors with the sealing of cement plugs are still limited, especially with the lack of proper equipment in the past.\u0000 In the present work, a small-scale laboratory setup has been constructed to test the sealing ability of a cement plug. It has unique features that can simulate plugging operations at the downhole conditions and preserve the cement curing condition. By testing using this setup, it is possible to measure the minimum differential pressure required for gas to flow across the cement plug and the gas leak rate. The silica cement mixture was selected as the plug material, prepared using silica flour. Investigation of silica cement under the influence of expanding agent additive and various curing temperature was carried out. It was found that adding an expanding agent improved the sealing of cement plugs. Moreover, samples cured at a high temperature were less resistant to gas flow with the leak path observed at the cement/steel interface, indicating debonding.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121152537","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":"The Calving Events of Petermann Glacier From 2008 to 2012: Ice Island Drift Characteristics, Assessment of Fracture Events, and Geographical Data Analysis","authors":"R. Torbati, I. Turnbull, R. Taylor, D. Mueller","doi":"10.1115/omae2019-96732","DOIUrl":"https://doi.org/10.1115/omae2019-96732","url":null,"abstract":"\u0000 The eastern Canadian Arctic is an ice-prone environment that is a vital part of Canadian Arctic shipping lanes. A better understanding of the ice environment and ice characteristics in this region is essential for supporting safe and economical marine activities. This study presents a first analysis of the drift of ice islands that originated from the Petermann Glacier calving events in northwest Greenland between 2008 and 2012. These massive calving events generated numerous smaller ice islands and icebergs through subsequent deterioration and break-up events. Surviving ice features drifted further southward into the Baffin Bay and reached as far as offshore Newfoundland (∼47 °N) for the case of the 2010 calving event. The drift characteristics of Petermann ice islands are evaluated through the analysis of the recently developed Canadian Ice Island Drift, Deterioration and Detection (CI2D3) database. The average drift distance, speed, and directions of the ice islands that resulted from the 2008, 2010, and 2012 calving events were estimated using successive observations of the monitored ice islands in the CI2D3 database. This study also includes an assessment of fracture events, including the total number of ice island break-up events following each massive calving event and the average number of daughter ice islands resulting from each break-up event. A geographical analysis of the data was also performed to present the location of the fracture events, as well as the time series of latitude change of Petermann ice islands from their origin (northwest Greenland ice tongues) to where until they became too small (< 0.25 km2) to be delineated in the CI2D3 database. This information is of particular interest to marine activities in the eastern Canadian Arctic, and oil and gas operations offshore Newfoundland and Labrador.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128913758","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":"Well Control Simulation With Non-Aqueous Drilling Fluids","authors":"Felipe Chagas, P. Ribeiro, O. Santos","doi":"10.1115/omae2019-96736","DOIUrl":"https://doi.org/10.1115/omae2019-96736","url":null,"abstract":"\u0000 The demand for energy has increased recently worldwide, requiring new oilfield discoveries in order to supply this need. Following this demand increase, challenges grow in all areas of the petroleum industry especially those related drilling operations. Due to hard operational conditions found when drilling complex scenarios such as high pressure/high temperature zones, deep and ultradeep waters and other challenging ones, the use non-aqueous drilling fluids became a must. The reason for that is because this kind of drilling fluid is capable to tolerate these extreme drilling conditions found in those scenarios. However, it can experience changes in its properties as results of pressure and temperature variations, requiring special attention during some drilling operations, such as the well control. The well control is a critical issue since it involves safety, social, economic and environmental aspects. To support well control operations and preserve the well integrity, well control simulators are very useful to verify operational parameters and to assist drilling engineers in the decision making process during well control operations and kick situations. Well control simulators are also important computational tools for rig personnel training. This work presents well control research and development contributions, as well as the results of a computational well control simulator that applies the Driller’s Method and allows the understanding the thermodynamic behavior of synthetic drilling fluids, such as n-paraffin and ester base fluids. The simulator employed mathematical correlations for the drilling fluids PVT properties obtained from experimental data.The simulator results were compared to a test well data set, as well to published results from other kick simulators.","PeriodicalId":444168,"journal":{"name":"Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133764901","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}