针对目前方面词情感分析方法忽视了以方面词为核心的局部特征的重要性,并难以有效减小情感干扰项的负面噪声的问题,本文提出了一种带有基于变换器的双向编码器表示技术(bi-directional encoder representations from transformers,BERT...针对目前方面词情感分析方法忽视了以方面词为核心的局部特征的重要性,并难以有效减小情感干扰项的负面噪声的问题,本文提出了一种带有基于变换器的双向编码器表示技术(bi-directional encoder representations from transformers,BERT)加持的双特征嵌套注意力模型(dual features attention-over-attention with BERT,DFAOA-BERT),首次将AOA(attention-over-attention)与BERT预训练模型结合,并设计了全局与局部特征提取器,能够充分捕捉方面词和语境的有效语义关联。实验结果表明:DFAOA-BERT在SemEval 2014任务4中的餐馆评论、笔记本评论和ACL-14 Twitter社交评论这3个公开数据集上均表现优异,而子模块的有效性实验,也充分证明了DFAOA-BERT各个部分的设计合理性。展开更多
Vortex-induced vibration is quite common during the operation of offshore risers or umbilical cables,commonly leading to serious damage to risers and reduced service life.Vortex-induced vibration of the offshore riser...Vortex-induced vibration is quite common during the operation of offshore risers or umbilical cables,commonly leading to serious damage to risers and reduced service life.Vortex-induced vibration of the offshore risers could be effectively suppressed by fairing devices.In this paper,a newly developed vortex-induced vibration fairing and large eddy simulation model of the FLUENT software were used for numerical analysis,experimental research and stimulating vortex-induced vibration at 0.1–2 ms^-1.The data of the numerical model with fairing was compared and analyzed to study the vortex shedding frequency at different Reynolds numbers and changes in drag and lift coefficients.The displacement state of 12 in risers with and without fairing was experimentally tested using a five degree-of-freedom balance.The vortex-induced vibration effect of the fairing was tested at different velocities.The result shows the drag reduction effect of the fairing is more obvious when the flow velocity is 0.4–1.2 ms^-1 and the maximum drag reduction reaches 55.6%when the flow velocity is 0.6 ms^-1.Additionally,the drag reduction effect was obvious when the flow velocity was greater than 1.3 ms^-1 and less than 0.3.The result indicates that the developed 12 in fairing,with good potential in engineering applications,has good vortex-induced vibration-suppression effects.展开更多
Based on the traditional numerical simulation and optimization algorithms,in combination with the layered injection and production"hard data"monitored at real time by automatic control technology,a systemati...Based on the traditional numerical simulation and optimization algorithms,in combination with the layered injection and production"hard data"monitored at real time by automatic control technology,a systematic approach for detailed water injection design using data-driven algorithms is proposed.First the data assimilation technology is used to match geological model parameters under the constraint of observed well dynamics;the flow relationships between injectors and producers in the block are calculated based on automatic identification method for layered injection-production flow relationship;multi-layer and multi-direction production splitting technique is used to calculate the liquid and oil production of producers in different layers and directions and obtain quantified indexes of water injection effect.Then,machine learning algorithms are applied to evaluate the effectiveness of water injection in different layers of wells and to perform the water injection direction adjustment.Finally,the particle swarm algorithm is used to optimize the detailed water injection plan and to make production predictions.This method and procedure make full use of the automation and intelligence of data-driven and machine learning algorithms.This method was used to match the data of a complex faulted reservoir in eastern China,achieving a fitting level of 85%.The cumulative oil production in the example block for 12 months after optimization is 8.2%higher than before.This method can help design detailed water injection program for mature oilfields.展开更多
This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adap...This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adaptability of oilfields in China,the development of separate zone oil production technology is divided into four stages:flowing well zonal oil production,mechanical recovery and water blocking,hydraulically adjustable zonal oil production,and intelligent zonal production.The principles,construction processes,adaptability,advantages and disadvantages of the technology are introduced in detail.Based on the actual production situation of the oilfields in China at present,three development directions of the technology are proposed.First,the real-time monitoring and adjustment level of separated zone oil production needs to be improved by developing downhole sensor technology and two-way communication technology between ground and downhole and enhancing full life cycle service capability and adaptability to horizontal wells.Second,an integrated platform of zonal oil production and management should be built using a digital artificial lifting system.Third,integration of injection and production should be implemented through large-scale application of zonal oil production and zonal water injection to improve matching and adjustment level between the injection and production parameters,thus making the development adjustment from"lag control"to"real-time optimization"and improving the development effect.展开更多
To study the fluid dynamic response mechanism under the working condition of water injection well borehole,based on the microelement analysis of fluid mechanics and the classical theory of hydrodynamics,a fluid microe...To study the fluid dynamic response mechanism under the working condition of water injection well borehole,based on the microelement analysis of fluid mechanics and the classical theory of hydrodynamics,a fluid microelement pressure-flow rate relationship model is built to derive and solve the dynamic distribution of fluid pressure and flow rate in the space of well borehole.Combined with the production data of a typical deviated well in China,numerical simulations and analyses are carried out to analyze the dynamic distribution of wellbore pressure at different injection pressures and injection volumes,the delayed and attenuated characteristics of fluid transmission in tube,and the dynamic distribution of wellbore pressure amplitude under the fluctuation of wellhead pressure.The pressure loss along the wellbore has nothing to do with the absolute pressure,and the design of the coding and decoding scheme for wave code communication doesn’t need to consider the absolute pressure during injecting.When the injection pressure is constant,the higher the injection flow rate at the wellhead,the larger the pressure loss along the wellbore.The fluid wave signal delay amplitude mainly depends on the length of the wellbore.The smaller the tubing diameter,the larger the fluid wave signal attenuation amplitude.The higher the target wave code amplitude(differential pressure identification root mean square)generated at the same well depth,the greater the wellhead pressure wave amplitude required to overcome the wellbore pressure loss.展开更多
文摘针对目前方面词情感分析方法忽视了以方面词为核心的局部特征的重要性,并难以有效减小情感干扰项的负面噪声的问题,本文提出了一种带有基于变换器的双向编码器表示技术(bi-directional encoder representations from transformers,BERT)加持的双特征嵌套注意力模型(dual features attention-over-attention with BERT,DFAOA-BERT),首次将AOA(attention-over-attention)与BERT预训练模型结合,并设计了全局与局部特征提取器,能够充分捕捉方面词和语境的有效语义关联。实验结果表明:DFAOA-BERT在SemEval 2014任务4中的餐馆评论、笔记本评论和ACL-14 Twitter社交评论这3个公开数据集上均表现优异,而子模块的有效性实验,也充分证明了DFAOA-BERT各个部分的设计合理性。
基金financially supported by the 7th Generation Ultra Deep-Water Drilling Unit Innovation Projectthe National Key Research and Development Plan(No.2016YFC0303400)+2 种基金the Fundamental Research Funds for the Central Universities(No.17CX02013A)the Natural Foundation of Shandong Province(Nos.ZR2017BEE031,ZR2017LEE032)the National Natural Science Foundation of China(No.51609201)
文摘Vortex-induced vibration is quite common during the operation of offshore risers or umbilical cables,commonly leading to serious damage to risers and reduced service life.Vortex-induced vibration of the offshore risers could be effectively suppressed by fairing devices.In this paper,a newly developed vortex-induced vibration fairing and large eddy simulation model of the FLUENT software were used for numerical analysis,experimental research and stimulating vortex-induced vibration at 0.1–2 ms^-1.The data of the numerical model with fairing was compared and analyzed to study the vortex shedding frequency at different Reynolds numbers and changes in drag and lift coefficients.The displacement state of 12 in risers with and without fairing was experimentally tested using a five degree-of-freedom balance.The vortex-induced vibration effect of the fairing was tested at different velocities.The result shows the drag reduction effect of the fairing is more obvious when the flow velocity is 0.4–1.2 ms^-1 and the maximum drag reduction reaches 55.6%when the flow velocity is 0.6 ms^-1.Additionally,the drag reduction effect was obvious when the flow velocity was greater than 1.3 ms^-1 and less than 0.3.The result indicates that the developed 12 in fairing,with good potential in engineering applications,has good vortex-induced vibration-suppression effects.
基金Supported by the Key Program of Petro China Exploration&Production Company(Grant No.kt2017-17-01-1 and kt2017-17-06-1)Consulting Project of Chinese Academy of Engineering(Grant No.2019-XZ-17)
文摘Based on the traditional numerical simulation and optimization algorithms,in combination with the layered injection and production"hard data"monitored at real time by automatic control technology,a systematic approach for detailed water injection design using data-driven algorithms is proposed.First the data assimilation technology is used to match geological model parameters under the constraint of observed well dynamics;the flow relationships between injectors and producers in the block are calculated based on automatic identification method for layered injection-production flow relationship;multi-layer and multi-direction production splitting technique is used to calculate the liquid and oil production of producers in different layers and directions and obtain quantified indexes of water injection effect.Then,machine learning algorithms are applied to evaluate the effectiveness of water injection in different layers of wells and to perform the water injection direction adjustment.Finally,the particle swarm algorithm is used to optimize the detailed water injection plan and to make production predictions.This method and procedure make full use of the automation and intelligence of data-driven and machine learning algorithms.This method was used to match the data of a complex faulted reservoir in eastern China,achieving a fitting level of 85%.The cumulative oil production in the example block for 12 months after optimization is 8.2%higher than before.This method can help design detailed water injection program for mature oilfields.
基金Supported by the National Key Research and Development Program of China(2018YFE0196000)National Science and Technology Major Project of China(2016ZX05010-006)CNPC Scientific Research and Technical Development Project(2019B-4113)
文摘This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adaptability of oilfields in China,the development of separate zone oil production technology is divided into four stages:flowing well zonal oil production,mechanical recovery and water blocking,hydraulically adjustable zonal oil production,and intelligent zonal production.The principles,construction processes,adaptability,advantages and disadvantages of the technology are introduced in detail.Based on the actual production situation of the oilfields in China at present,three development directions of the technology are proposed.First,the real-time monitoring and adjustment level of separated zone oil production needs to be improved by developing downhole sensor technology and two-way communication technology between ground and downhole and enhancing full life cycle service capability and adaptability to horizontal wells.Second,an integrated platform of zonal oil production and management should be built using a digital artificial lifting system.Third,integration of injection and production should be implemented through large-scale application of zonal oil production and zonal water injection to improve matching and adjustment level between the injection and production parameters,thus making the development adjustment from"lag control"to"real-time optimization"and improving the development effect.
基金Supported by the National Natural Science Foundation of China(52074345)CNPC Research and Technology Development Project(2021ZG12).
文摘To study the fluid dynamic response mechanism under the working condition of water injection well borehole,based on the microelement analysis of fluid mechanics and the classical theory of hydrodynamics,a fluid microelement pressure-flow rate relationship model is built to derive and solve the dynamic distribution of fluid pressure and flow rate in the space of well borehole.Combined with the production data of a typical deviated well in China,numerical simulations and analyses are carried out to analyze the dynamic distribution of wellbore pressure at different injection pressures and injection volumes,the delayed and attenuated characteristics of fluid transmission in tube,and the dynamic distribution of wellbore pressure amplitude under the fluctuation of wellhead pressure.The pressure loss along the wellbore has nothing to do with the absolute pressure,and the design of the coding and decoding scheme for wave code communication doesn’t need to consider the absolute pressure during injecting.When the injection pressure is constant,the higher the injection flow rate at the wellhead,the larger the pressure loss along the wellbore.The fluid wave signal delay amplitude mainly depends on the length of the wellbore.The smaller the tubing diameter,the larger the fluid wave signal attenuation amplitude.The higher the target wave code amplitude(differential pressure identification root mean square)generated at the same well depth,the greater the wellhead pressure wave amplitude required to overcome the wellbore pressure loss.
