Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with...Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with hydraulic fracturing in a relatively high confidence level and accuracy.In this study,we present a multidimensional DIRECT inversion method for microseismic locations and applicability tests over modeling data based on a downhole microseismic monitoring system.Synthetic tests inidcate that the objective function of locations can be defined as a multi-dimensional matrix space by employing the global optimization DIRECT algorithm,because it can be run without the initial value and objective function derivation,and the discretely scattered objective points lead to an expeditious contraction of objective functions in each dimension.This study shows that the DIRECT algorithm can be extensively applied in real downhole microseismic monitoring data from hydraulic fracturing completions.Therefore,the methodology,based on a multidimensional DIRECT algorithm,can provide significant high accuracy and convergent efficiency as well as robust computation for interpretable spatiotemporal microseismic evolution,which is more suitable for real-time processing of a large amount of downhole microseismic monitoring data.展开更多
In order to evaluate the service level of roundabouts intuitively, a new delay model of signalized roundabouts is established. According to traffic flow characteristics in the signalized roundabout, vehicle delays on ...In order to evaluate the service level of roundabouts intuitively, a new delay model of signalized roundabouts is established. According to traffic flow characteristics in the signalized roundabout, vehicle delays on roundabouts are divided into two parts: entrance delay and circulating lane delay. Entrance delay is calculated by the delay model in HCM2010. Circulating lane delay is studied by analyzing conflict behavior in signalized roundabouts, and the delay models of traffic flows turning in different directions are established based on the motorcade analysis method. Finally,the simulation software Vissim, calibrated with field data, is used to verify the model. The simulation results showthat the average relative error of the model is 10. 1%, meeting the accuracy requirements. Therefore, the delay model properly reflects the operation efficiency of a roundabout, and can thus provide a scientific basis for the design of control schemes.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 41807296 and No. 41802006)Natural science found for universities of Anhui province (Grant No. KJ2017A036)
文摘Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with hydraulic fracturing in a relatively high confidence level and accuracy.In this study,we present a multidimensional DIRECT inversion method for microseismic locations and applicability tests over modeling data based on a downhole microseismic monitoring system.Synthetic tests inidcate that the objective function of locations can be defined as a multi-dimensional matrix space by employing the global optimization DIRECT algorithm,because it can be run without the initial value and objective function derivation,and the discretely scattered objective points lead to an expeditious contraction of objective functions in each dimension.This study shows that the DIRECT algorithm can be extensively applied in real downhole microseismic monitoring data from hydraulic fracturing completions.Therefore,the methodology,based on a multidimensional DIRECT algorithm,can provide significant high accuracy and convergent efficiency as well as robust computation for interpretable spatiotemporal microseismic evolution,which is more suitable for real-time processing of a large amount of downhole microseismic monitoring data.
基金The National Natural Science Foundation of China(No.51278520,51278220)the Postdoctoral Science Foundation of China(No.2014M551178)the Science and Technology Development Project of Jilin Province(No.20130206093SF)
文摘In order to evaluate the service level of roundabouts intuitively, a new delay model of signalized roundabouts is established. According to traffic flow characteristics in the signalized roundabout, vehicle delays on roundabouts are divided into two parts: entrance delay and circulating lane delay. Entrance delay is calculated by the delay model in HCM2010. Circulating lane delay is studied by analyzing conflict behavior in signalized roundabouts, and the delay models of traffic flows turning in different directions are established based on the motorcade analysis method. Finally,the simulation software Vissim, calibrated with field data, is used to verify the model. The simulation results showthat the average relative error of the model is 10. 1%, meeting the accuracy requirements. Therefore, the delay model properly reflects the operation efficiency of a roundabout, and can thus provide a scientific basis for the design of control schemes.
