Day 2 Tue, May 07, 2019最新文献

{"title":"A Novel Thermo-Electric Technique to Evaluate Asphaltene Stability and Inhibitor Efficiency in Native Crude Oil Medium","authors":"A. Punase, Claudia Mazzeo, P. Hart, A. Mahmoudkhani, J. Wylde","doi":"10.4043/29275-MS","DOIUrl":"https://doi.org/10.4043/29275-MS","url":null,"abstract":"\u0000 Asphaltenes represent the most polar solubility fraction of crude oil. The polar-polar interactions between asphaltene-water, asphaltene-clay, or asphaltene-asphaltene molecules can cause severe flow assurance issues in the oilfield such as formation of highly stable emulsion, pore-throat blockages within the reservoir, and plugging of production and transportation flowlines. A novel approach of understanding these polar interactions through thermo-electric measurements is presented in this study, which can evaluate overall asphaltene stability in native crude oil.\u0000 Most of the techniques currently being used to assess asphaltene stability and efficiency of different asphaltene inhibitors on preventing asphaltene deposition are based on light scattering and transmittance phenomenon. Since crude oils are intrinsically dark colored, these techniques require dilution of the oil sample with solvents like toluene and xylene or precipitants like pentane and heptane. Addition of these chemicals alters the nature and thermodynamic equilibrium of crude oil solubility fractions. Thus, a novel approach of measuring the thermo-electric properties of crude oil and crude oil-asphaltene inhibitor mixtures was developed and tested using a custom-built capacitor setup.\u0000 The thermo-electric measurements were conducted on 10 different crude oil samples. These samples were altogether tested with 10 asphaltene inhibitors (AI). Measured data was used to indirectly estimate the polarity of the test sample, which is related to the dispersion efficiency of the asphaltene inhibitor. A standard light scattering technique was also used to analyze the oil and oil-inhibitor samples and the results were compared to the thermo-electric method outcomes. It should be noted that some of the oil samples tested in this study were obtained from production systems having asphaltene deposition issues and undergoing effective prevention and remediation treatment. Therefore, it is important for the success of the new technique to not only correlate with the standard light scattering test results but also be able to precisely the efficacy of asphaltene inhibitors for each of the test oil samples. From the results obtained, it was observed that using the thermo-electric method, the asphaltene inhibitors can be accurately screened for all the oil samples and the inhibitor efficiency analyzed in terms of its dosage curve, also agrees well with the conditions observed in the field.\u0000 A strong correlation between the results obtained from the thermo-electric technique and the light scattering method indicates the validity and higher-level accuracy of the innovative technique. Moreover, direct application of this method on the production platform at the well-head using the native crude oil sample highlights the versitality of this novel method. In addition to testing overall asphaltene stability and inhibitor efficiency, the method can also be used to monitor and optimize the field scale produ","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"90930529","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":"Research and Application of LWD Geosteering Technology Based on Geophysical Inversion","authors":"Meng Zhu, Yunjiang Cui, C. Ma, Jinxiu Xu, Wei Yang, Ting Li","doi":"10.4043/29310-MS","DOIUrl":"https://doi.org/10.4043/29310-MS","url":null,"abstract":"\u0000 Caofeidian oilfield in Bohai Sea has the characteristics of low structural amplitude, low oil column height, complex structure and reservoir change, complex fluid system, large reserve of bottom water reservoir, and all use horizontal well development. How to accurately control the well trajectory to make the horizontal well successfully landing, improve the level of drilling encounter rate, to achieve the ideal height of water protection is the key to achieve the optimal development effect. After many years of development, the geological-oriented technology has been adopted for the drilling of the oil field, which has achieved good application results. However, with the development of the oil field, the reservoir changes facing at present are more complex, and the reservoir with lower oil column height, which is limited by the density of the offshore well net, the traditional Geological guidance technology of follow-drill logging has great limitations, and it satisfies the implementation requirements of horizontal well.\u0000 Aiming at the above problems, the seismic attributes are connected with the logging curve through the cluster analysis method, and the natural gamma and over-well seismic attributes (maximum amplitude) are innovated) the relationship between the resistivity and the natural gamma curve is established, and the pre-drilling geological guidance model is established.\u0000 This method not only gives the meaning of seismic attribute logging, it also solves the shortcomings of the traditional modeling error caused by the large horizontal difference between the design wells and the guide wells, the difference of fluid properties and the small detection of the fan enclosure. At the same time, the geological guidance technology in Caofeidian Oil Field low oil column bottom water reservoir with Drilling Technology series, improve the landing prediction accuracy and level segment well trajectory control ability. In the past three years, nearly 50 horizontal wells were implemented in Caofeidian Oilfield, and the average oil layer drilling rate of the horizontal segment reached 90, according to statistics, it has improved 10% on the drilling encounter rate before using the geological guidance technology, which is also adaptive in other oil fields, and 4 horizontal wells were drilled in the B oilfield in 2018, the gamma-ray and resistivity curves of non-drilled sand bodies above the target layer have been successfully retrieved, and the aim of accurately guiding the horizontal well landing has been achieved.\u0000 Geosteering services could improve geological reservoir development effect, decrease difficulty in drilling and completion engineering, reduce drilling cycle, and enhance economic performance of oil & gas field development. The authors believe that scientific and effective development of oil & gas fields requires all departments and professions to cooperate closely, and the cooperation could get more perfect by timely using geosteering servi","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"84094092","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":"Review of Technology Status and Challenges Associated with Ultra Deep Water Developments","authors":"G. Singhal, O. Dibua, D. Murray, Laurent Culembourg, P. Erb, E. Wensel, T. Makogon","doi":"10.4043/29229-MS","DOIUrl":"https://doi.org/10.4043/29229-MS","url":null,"abstract":"\u0000 A review of current technology limits and challenges that exist for surface facilities (topsides and hull), subsea and flow assurance aspects for ultra deepwater developments (>3,000m or 10,000ft) is presented. Gap assessments are performed to identify components that require development and / or qualification at greater water depths than their current design / qualification depth. Technology readiness level (TRL) is presented for assessment of existing technologies. A summary of current confidence level for various components of a field development (i.e. subsea, topsides, hull, mooring, risers) is also provided. Given the current state of the industry, the paper also addresses project economics, risks and uncertainties when evaluating opportunities in such water depths.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"74631793","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":"Simulation Modeling of Offshore Energy Systems & Processes - A Primer","authors":"R. Dronzek","doi":"10.4043/29467-MS","DOIUrl":"https://doi.org/10.4043/29467-MS","url":null,"abstract":"\u0000 An introduction to the history, concepts, use cases and technology of dynamic computer-based simulation modeling, including case studies and model demonstrations. The focus of this paper is how simulation models are developed to analyze and predict the performance of a wide range of systems and processes in the energy sector.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"91216762","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":"Leveraging Online Analytical Processing Cubes in the World's Largest Offshore and Land Drilling Record System","authors":"Luke Kuwertz, James Neill, R. Santana, Greg Skoff, Stephen Claude Steinke, John F. Williams, Preston Wolfram, D. Fink","doi":"10.4043/29457-MS","DOIUrl":"https://doi.org/10.4043/29457-MS","url":null,"abstract":"\u0000 The purpose of this paper is to demonstrate the power and business benefits of leveraging online analytical processing (OLAP) cubes in the utilization of high-level data analytics and data dashboards from an established drilling record system (DRS). The DRS contains over 1.4 million wells, including 75,000 offshore wells drilled worldwide since 1980 with nearly 5 million total bottomhole assembly (BHA) runs from over 100 countries. Since 2009, over 1.5 million BHA runs drilling 2.6 billion feet of formation have been captured. Being able to visualize and understand the drilling data allows for increased efficiencies, reducing the days on wells for operators from deepwater to inland barge and land drilling worldwide.\u0000 The development of the OLAP cubes required a multidisciplinary team consisting of software developers, business managers, domain champions, field-based engineers, and data scientists. The OLAP cubes consist of multidimensional databases built from relational and algorithmic interpretations of DRS transaction data. These algorithms are generated and developed by an iterative cycle of continuous improvement, development, and utilization of the OLAP cubes in parallel to improve the functionality and business impact for performance analysis, sales, product development, product reliability, and marketing. The data can be analyzed and visualized in the Microsoft Office suite by directly querying the DRS OLAP cubes. This also allows for dashboards to be updated in real time as data are added to DRS.\u0000 OLAP cubes have been developed to analyze the performance of drill bits, motors, reamers, rotary steerable tools, and many more downhole tools. The DRS cubes assist in identifying failure causes on bits to identify high-risk intervals to better target products and parameters to reduce costly nonproductive time. Fit-for-purpose OLAP cubes have been developed to understand drilling efficiencies and strategies in multibit versus single-bit sections using variable trip speeds and field performance. Traditional business reports were made more efficient and auto-updated and dashboards were built to identify major business trends to equip business managers.\u0000 This OLAP cube development has allowed for increased usage of the world's largest drilling record database and has made it easier to access and analyze the data. Ultimately, the techniques and development described in this paper help answer business questions to make better business decisions through data-driven analytics.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"90142772","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":"SLWR Innovative Design Methodology Supporting Concept Engineering Through to Project Cost Optimisation","authors":"E. Diakonova, G. Bonnet, Y. Brouard","doi":"10.4043/29529-MS","DOIUrl":"https://doi.org/10.4043/29529-MS","url":null,"abstract":"\u0000 Steel Lazy Wave Risers are one of the most efficient and compliant riser systems for deep-water projects.\u0000 From a design perspective, designers have to deal with parameters such as the configuration itself, interaction with the FPSO, environmental loads, installation vessel capabilities and commercial issues like installation and procurement costs.\u0000 This paper presents how to assess the need for Steel Lazy Wave Risers (as opposed to conventional Steel Catenary Risers) and how to develop a state of the art design by using an innovative methodology based on the efficiency of an optimisation through modern technology computation.\u0000 The objective of the optimisation is to propose a riser configuration that allows the best compromise between all parameters, while remaining fit for purpose and cost-efficient. A methodology was developed using a Python script as an interface between Orcaflex software and the user-defined parameters to best respect the project specific weighted criteria.\u0000 It will also highlight how the methodology can be applied for fast track conceptual studies, enabling the end user to account for optimised design at the start-up of a field development. All the constraints and objectives will be considered with possible challenges and solutions to be presented.\u0000 The final design of a lazy waver riser is a compromise between all constraints.\u0000 This paper provides comprehensive information relative to all the stages of steel lazy wave riser design, from the initial draft configuration to the most optimised and cost-efficient one. A few optimisation possibilities achieved thanks to this process will be developed and illustrated through examples. The concept can be applied to early stage engineering or during the course of a project.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"86762520","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":"Optimization of Drilling in Deep-Offshore Gulf of Mexico Using Geomechanics: Example from Buckskin","authors":"T. Ait-Ettajer, F. Giannangeli, J. Wood, John White, A. Litun","doi":"10.4043/29652-MS","DOIUrl":"https://doi.org/10.4043/29652-MS","url":null,"abstract":"\u0000 The optimization of the field development in the deepwater Gulf of Mexico (GOM) requires the collaboaration of multiple disciplines including drilling, geophysics, geology, petrophysics and geomechanics. The latter has been on the rise for several decades (Brehm, Davis, Ward, & Bowman, 2004) (Crawford, Homburg, Freysteinson, & Amoruso, 2018) (Zaki, Li, & Clinton, 2018), and it contributed to adding value through reducing the cost and the risks of drilling and completion in geologically complex areas such as the lower tertiary Wilcox. In the case of Buckskin field (Keathely Canyon), the use of 1D and 3D geomechanics techniques was necessary for the optimization of the drilling of the first development well in 2018, due to the high geological complexity (Ait-Ettajer, et al., 2017) and the chosen drilling design that included a highly deviated section through the reservoir section, in order to ensure a maximum reservoir contact and high well deliverability.\u0000 The geomechanics study, combined with a regional and local structural geology evaluation, indicated that the optimal well azimuth for the reservoir section is along the maximum horizontal stress since the tectonic regime is strike-slip (Tiwari, 2013), and that the completion integrity will be maintained throughout the life of the well. The results of the geomechanics study were in line with the prediction and ensured the injection of more than 4 million pounds of proppant in the reservoir section.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"87561788","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":"Experimental Measurement of Touchdown Zone Stiffness for SCR in Gulf of Mexico Clay","authors":"Husham A. Al-Janabi, C. Aubeny, Jinbo Chen, Meng Luo","doi":"10.4043/29504-MS","DOIUrl":"https://doi.org/10.4043/29504-MS","url":null,"abstract":"\u0000 The location near the touchdown zone (TDZ) of a Steel Catenary Riser (SCR) onto the seabed is a primary \"hot spot\" for fatigue-assessment, with seabed stiffness having a major influence on the predicted fatigue life. This paper presents the results of laboratory model tests evaluating the effects of cyclic loading, loading rate, load amplitude, riser embedment depth and consolidation on the vertical stiffness of the soil supporting the riser in the TDZ.\u0000 Monotonic and cyclic model tests using single gravity, displacement-controlled laboratory model tests of soil stiffness were conducted. All tests used high plasticity Gulf of Mexico clay with undrained shear strength corresponding to typical normally consolidated conditions. A test program was developed to evaluate: (1) rate effects for monotonic and cyclic loading, (2) vertical stiffness for displacement amplitudes ranging from 0.02-0.05 D (where D = riser outer diameter), (3) soil stiffness degradation with increasing in the number of cycles, (4) stiffness recovery during rest periods, and (5) stiffness recovery under prolonged cyclic loading.\u0000 The results show that the cyclic resistance during a shallow embedment, 0.5 D, and large amplitude-cycles, 0.05 D, drops significantly during the first few cycles in the displacement-controlled cyclic loading. The resistance will continue to drop and approaches zero after about one hundred cycles for both the penetration and the extraction resistance. By contrast, for small amplitude-cycles, 2% D, soil resistance degrades during the first few cycles, but reaches an apparent steady state at larger cycles. After the pause periods, ranging from 1 to 13 hours, and after each series of 100 cycle parcels, the vertical displacements occurring during consolidation were recorded. Consolidation following rest periods leads to a short-term increase in the soil secant stiffness, which quickly declines to pre-rest period levels after the resumption of cyclic loading. However, under prolonged cyclic loading the soil stiffness gradually trends upward.\u0000 The test program adds to the database evaluating the influence of the major variables (displacement magnitude, embedment depth, etc.) affecting soil stiffness for SCR fatigue-assessment. Additionally, it presents new results on stiffness recovery during rest periods, stiffness reduction after resumed cyclic loading, and gradual gains in stiffness under prolonged cyclic loading. The findings on stiffness recovery are particularly important, as this has been a major source of uncertainty in prior investigations.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"76428981","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":"Innovative Oil Offloading System for Deep Water","authors":"J. B. Araujo, A. C. Fernandes, J. S. Sales, Ana Clara Thurler, A. Vilela","doi":"10.4043/29443-MS","DOIUrl":"https://doi.org/10.4043/29443-MS","url":null,"abstract":"\u0000 Offshore oil production with the employment of FPSOs (Floating, Production, Storage and Offloading) unit faces the challenge of increasing well volumes, processing and storage capacity and ultimately oil offloading and transportation. Following the natural activity development in some oil fields, the number of spread-moored FPSOs and the employment of Dynamic Positioning Shuttle Tankers increased, however represent altogether a bottleneck for the production capacity and considerable transportation cost increment. The need to implement alternatives for the use of larger and conventional tankers is evident, and several attempts and use of technology are being tested and proposed. The work presents preliminary numerical and cost analysis of an innovative Oil Loading Terminal (OLT) for deep water.\u0000 Based on field data, metocean studies and extensive practical experience, the OLT should allow direct offloading from the FPSOs onto conventional shuttle tankers including VLCCs. The OLT concept allows the transfer of oil from an FPSO to a conventional tanker moored in CALM Buoy through submerged oil offloading lines (OOLs) supported by a tethered submerged buoy. The conventional tanker will receive the oil through a floating hose string.\u0000 The cornerstone of this OLT concept is the subsurface buoy application to support the OLLs and consequently de-coupling the FPSO and CALM Buoy motions simultaneously. As a result, the OOLs loads and fatigue efforts under the CALM Buoy also decrease. The paper evaluates an OLT specific conception for the Brazilian offshore pre-salt area and results related to the numerical analysis carried out are presented considering one submerged buoy connected to a FPSO and CALM Buoy via flexible offloading lines respectively. The results appoint to a technically feasible solution that can be complementarily laboratory and field tested. Further, the solution cost impact has been assessed and initial figures demonstrate that the final testing, construction and installation of one system will need investment that cost a fraction of tanker lifting costs currently requiring Ship-to-Ship oil transfers.\u0000 The economies assessed with the use of this innovative solution include total avoidance of Ship-to-Ship costs; cuts transportation cost per ton in up to 50% (fifty percent), eliminates offloading bottlenecks allowing better use of FPSO storage and plant processing capacity, and ultimately decreases the number of tanker offloading operations with considerable benefit to operational safety by reducing risk exposure.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"80018851","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":"SCR with FPSO Design Challenges Subject to Complex Bi-Modal, Bi-Directional Environment in Ultra-Deep Water","authors":"Vinanti Shah, Raymond P. Fales","doi":"10.4043/29596-MS","DOIUrl":"https://doi.org/10.4043/29596-MS","url":null,"abstract":"\u0000 This paper discusses steel catenary riser (SCR) design challenges subject to complex bi-modal and bi-directional seastates offshore West Africa in ultra-deepwater (2,600m). Metocean data is key to determining the design of SCRs. As offshore exploration continues in remote regions and deeper water depths, it is very important to obtain accurate and comprehensive environmental data for the field. Different locations around the world have distinct offshore environments such as hurricanes, typhoons, swells and squalls with seastates exhibiting a varying range of frequency content. The work in this paper describes effects of multiple seastate modes on the riser’s performance. The risers evaluated are 10 inch production and 18 inch export SCRs connected to a spread moored FPSO. Riser fatigue was particularly challenging given the unique environment consisting of up to four wave modes in a single sea-state. Several sensitivities were performed to improve the fatigue performance of the risers. Finally a feasible riser concept was selected which met all of the project design requirements. Work showcased in this paper will address the challenges of placing steel catenary risers in remote deep water fields with relatively unfamiliar metocean conditions. Several sensitivities are performed with the riser properties, platform motions and environmental data which help to reduce design conservatism and better understand the fatigue response of SCRs connected to a spread moored FPSO.","PeriodicalId":10948,"journal":{"name":"Day 2 Tue, May 07, 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":"76670272","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}