With the maturation of coalbed methane(CBM)exploitation and the transition into the late stages of dewatering and gas production,liquid loading in gathering pipelines has emerged as a major constraint on productivity ...With the maturation of coalbed methane(CBM)exploitation and the transition into the late stages of dewatering and gas production,liquid loading in gathering pipelines has emerged as a major constraint on productivity and operational stability.Based on real-time field data and gas-liquid physicochemical analyses,this study elucidates the mechanisms governing liquid loading formation under varying temperature,pressure,and water saturation conditions.An HYSYS model is employed to determine the water dew point,while the Turner model is used to evaluate the critical conditions for liquid holdup.The results indicate that gas water saturation exerts the dominant influence on liquid loading risk,followed by pressure,whereas temperature plays a comparatively minor role.When water saturation exceeds 2%and the operating temperature falls below the dew point,condensation-driven liquid loading increases sharply.To further characterize the spatial distribution of liquid accumulation,a steady-state OLGA model of a DN100 gathering pipeline network is developed to examine the effects of pipe diameter,water saturation,and soil temperature.The simulations show that larger pipe diameters and higher water saturation significantly aggravate liquid holdup,while elevated soil temperature mitigates liquid accumulation.Moreover,the liquid holdup ratio is found to correlate closely with flow regime transitions,confirming its suitability as a key indicator of liquid loading risk.Based on these findings,optimization strategies for pipeline design and operation are proposed.To mitigate liquid loading,the gathering pipeline velocity should be maintained above the critical value of 1.63 m/s,and the gas water content should be strictly controlled below 2%.Under operating conditions representative of the Hancheng block,it is recommended to reduce the pipeline diameter from DN130 to DN100 to enhance self-cleaning capacity.In addition,thermal insulation should be applied during winter operation to maintain the pipe wall temperature above 10◦C,thereby suppressing condensation-induced liquid accumulation.展开更多
Pre-stack depth migration velocity analysis is one of the keys to influencing the imaging quality of pre-stack migration.In this paper we cover a residual curvature velocity analysis method on angle-domain common imag...Pre-stack depth migration velocity analysis is one of the keys to influencing the imaging quality of pre-stack migration.In this paper we cover a residual curvature velocity analysis method on angle-domain common image gathers（ADCIGs） which can depict the relationship between incident angle and migration depth at imaging points and update the migration velocity.Differing from offset-domain common image gathers（ODCIGs）,ADCIGs are not disturbed by the multi-path problem which contributes to imaging artifacts,thus influencing the velocity analysis.On the basis of horizontal layers,we derive the residual depth equation and also propose a velocity analysis workflow for velocity scanning.The tests to synthetic and field data prove the velocity analysis methods adopted in this paper are robust and valid.展开更多
Reverse Time Migration(RTM)Surface Ofset Gathers(SOGs)are demonstrated to deliver more superior residual dip information than ray-based approaches.It appears more powerful in complex geological settings,such as salt a...Reverse Time Migration(RTM)Surface Ofset Gathers(SOGs)are demonstrated to deliver more superior residual dip information than ray-based approaches.It appears more powerful in complex geological settings,such as salt areas.Still,the computational cost of constructing RTM SOGs is a big challenge in applying it to 3D feld data.To tackle this challenge,we propose a novel method using dips of local events as a guide for RTM gather interpolation.The residual-dip information of the SOGs is created by connecting local events from depth-domain to time-domain via ray tracing.The proposed method is validated by a synthetic experiment and a feld example.It mitigates the computational cost by an order of magnitude while producing comparable results as fully computed RTM SOGs.展开更多
Angle-domain common-image gathers （ADCIGs） transformed from the shot- domain common-offset gathers are input to migration velocity analysis （MVA） and prestack inversion. ADCIGs are non-illusion prestack inversion ...Angle-domain common-image gathers （ADCIGs） transformed from the shot- domain common-offset gathers are input to migration velocity analysis （MVA） and prestack inversion. ADCIGs are non-illusion prestack inversion gathers, and thus, accurate. We studied the extraction of elastic-wave ADCIGs based on amplitude-preserving elastic-wave reverse- time migration for calculating the incidence angle of P- and S-waves at each image point and for different source locations. The P- and S-waves share the same incident angle, namely the incident angle of the source P-waves. The angle of incidence of the source P-wavefield was the difference between the source P-wave propagation angle and the reflector dips. The propagation angle of the source P-waves was obtained from the polarization vector of the decomposed P-waves. The reflectors＇ normal direction angle was obtained using the complex wavenumber of the stacked reverse-time migration （RTM） images. The ADCIGs of P- and S-waves were obtained by rearranging the common-shot migration gathers based on the incident angle. We used a horizontally layered model, the graben medium model, and part of the Marmousi-II elastic model and field data to test the proposed algorithm. The results suggested that the proposed method can efficiently extract the P- and S-wave ADCIGs of the elastic-wave reverse-time migration, the P- and S-wave incident angle, and the angle-gather amplitude fidelity, and improve the MVA and prestack inversion.展开更多
Kirchhoff beam migration is a simplified Gaussian beam migration,which omits the dynamic information and can calculate multi-arrival traveltime,so it is a high-precision and fast seismic imaging method.In the imaging ...Kirchhoff beam migration is a simplified Gaussian beam migration,which omits the dynamic information and can calculate multi-arrival traveltime,so it is a high-precision and fast seismic imaging method.In the imaging process,extracting common image gathers can be used for velocity analysis,improving the accuracy of modeling and imaging quality.Compared with the conventional common image gathers extracting methods,the angle-domain common image gathers extracting method can avoid the artifacts caused by multi-arrival seismic waves.The authors present a new method of extracting common image gathers in angle-domain from Kirchhoff beam migration and verify the method by numerical calculations.展开更多
Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transfor...Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transform or low-rank approximation,which requires much computation.Based on an anisotropic-Helmholtz P/S wave-mode decomposition method,we propose a novel and efficient approach to produce angle-domain common-image gathers(ADCIGs)in the elastic reverse time migration(ERTM)of VTI media.To start with,we derive an anisotropic-Helmholtz decomposition operator from the Christoffel equation in VTI media,and use this operator to derive the decomposed formulations for anisotropic P/S waves.Second,we employ the first-order Taylor expansion to calculate the normalized term of decomposed formulations and obtain the anisotropic-Helmholtz decomposition method,which generates the separated P/S wavefields with correct amplitudes and phases.Third,we develop a novel way that uses the anisotropic-Helmholtz decomposition operator to define the polari-zation angles for anisotropic P/S waves and substitute these angles to decomposing formulations.The polarization angles are then calculated directly from the separated vector P-and S-wavefields and converted to the phase angles.The ADCIGs are thusly produced by applying the phase angles to VTI ERTM.In addition,we develop a concise approximate expression of residual moveout(RMO)for PP-reflections of flat reflectors in VTI media,which avoids the complex transformations between the group angles and the phase angles.The approximate RMO curves show a good agreement with the exact solution and can be used as a tool to assess the migration velocity errors.As demonstrated by two selected examples,our ADCIGs not only produce the correct kinematic responses with regards to different velocity pertubatation,but also generate the reliable amplitude responses versus different angle.The final stacking images of ADCIGs data exhibit the identical imaging effect as that of VTI ERTM.展开更多
The dip-angle-domain common-image gather(DDCIG)is a key tool to separate the diffraction and reflection imaging results.Reflectors with different spatial geometries produce different responses in DDCIGs.Compared with ...The dip-angle-domain common-image gather(DDCIG)is a key tool to separate the diffraction and reflection imaging results.Reflectors with different spatial geometries produce different responses in DDCIGs.Compared with Kirchhoff migration,Gaussian beam migration(GBM)is more effective and robust to overcome the multipathing problem.As a ray-based method,it has explicit angle information naturally during the propagation.We have developed a 3D DDCIG computational method using GBM,which obtain both the imaging result and angle-domain gathers with only one pass of calculation.The angle-gather computation is based on geometrical optics,and multiple angle conversions are implemented under the rules of space geometry,which helps to avoid rounding errors and improve accuracy.Additionally,the multi-azimuth joint presentation strategy is proposed to describe the characteristic of omnidirectional dip angles using a finite number of gathers.After using a 2D model to illustrate application advantages of DDCIG,we apply the proposed method to two 3D models to test its feasibility and accuracy.A field data example further demonstrates the adaptability of our method to seismic imaging for a land survey.展开更多
The hydrocarbon detection method based on pre-stack gather data has higher accuracy and reliability than those methods based on post-stack data.This kind of method requires that pre-stack gather data have high SNR(Sig...The hydrocarbon detection method based on pre-stack gather data has higher accuracy and reliability than those methods based on post-stack data.This kind of method requires that pre-stack gather data have high SNR(Signal Noise Ratio)and obvious AVO(amplitude variation with offset)characteristics.Therefore,it is important to optimize the pre-stack gathers and enhance their AVO(Amplitude variation with offset)effect.This abstract proposes a gather optimization and AVO feature enhanced method for hydrocarbon detection.The gather optimization method based on the improved BEMD(bidimensional empirical mode decomposition).It starts from the original signal directly,and can be optimized as pre-stack gather steadily and quickly.Then,the characters of CTKEO(Corss Teager-Kaiser energy)algorithm which is strong sensitivity to interaction of two signals is fully utilized to enhance AVO features.The method proposed in this abstract provides a good data base for pre-stack inversion from gather optimization to AVO feature enhancement.展开更多
一、请根据录音,填写单词。二、听对话,选择正确的答案。1.Who is coming for dinner?A.Friends.B.Aunt and uncle.C.Grandma and grandpa.2.What does Dad offer to do at the beginning?A.Go shopping.B.Set the table.C.Cook the fish.
Research on mass gathering events is critical for ensuring public security and maintaining social order.However,most of the existing works focus on crowd behavior analysis areas such as anomaly detection and crowd cou...Research on mass gathering events is critical for ensuring public security and maintaining social order.However,most of the existing works focus on crowd behavior analysis areas such as anomaly detection and crowd counting,and there is a relative lack of research on mass gathering behaviors.We believe real-time detection and monitoring of mass gathering behaviors are essential formigrating potential security risks and emergencies.Therefore,it is imperative to develop a method capable of accurately identifying and localizing mass gatherings before disasters occur,enabling prompt and effective responses.To address this problem,we propose an innovative Event-Driven Attention Network(EDAN),which achieves image-text matching in the scenario of mass gathering events with good results for the first time.Traditional image-text retrieval methods based on global alignment are difficult to capture the local details within complex scenes,limiting retrieval accuracy.While local alignment-based methods aremore effective at extracting detailed features,they frequently process raw textual features directly,which often contain ambiguities and redundant information that can diminish retrieval efficiency and degrade model performance.To overcome these challenges,EDAN introduces an Event-Driven AttentionModule that adaptively focuses attention on image regions or textual words relevant to the event type.By calculating the semantic distance between event labels and textual content,this module effectively significantly reduces computational complexity and enhances retrieval efficiency.To validate the effectiveness of EDAN,we construct a dedicated multimodal dataset tailored for the analysis of mass gathering events,providing a reliable foundation for subsequent studies.We conduct comparative experiments with other methods on our dataset,the experimental results demonstrate the effectiveness of EDAN.In the image-to-text retrieval task,EDAN achieved the best performance on the R@5 metric,while in the text-to-image retrieval task,it showed superior results on both R@10 and R@5 metrics.Additionally,EDAN excelled in the overall Rsummetric,achieving the best performance.Finally,ablation studies further verified the effectiveness of event-driven attention module.展开更多
In order to solve the problems of short network lifetime and high data transmission delay in data gathering for wireless sensor network(WSN)caused by uneven energy consumption among nodes,a hybrid energy efficient clu...In order to solve the problems of short network lifetime and high data transmission delay in data gathering for wireless sensor network(WSN)caused by uneven energy consumption among nodes,a hybrid energy efficient clustering routing base on firefly and pigeon-inspired algorithm(FF-PIA)is proposed to optimise the data transmission path.After having obtained the optimal number of cluster head node(CH),its result might be taken as the basis of producing the initial population of FF-PIA algorithm.The L′evy flight mechanism and adaptive inertia weighting are employed in the algorithm iteration to balance the contradiction between the global search and the local search.Moreover,a Gaussian perturbation strategy is applied to update the optimal solution,ensuring the algorithm can jump out of the local optimal solution.And,in the WSN data gathering,a onedimensional signal reconstruction algorithm model is developed by dilated convolution and residual neural networks(DCRNN).We conducted experiments on the National Oceanic and Atmospheric Administration(NOAA)dataset.It shows that the DCRNN modeldriven data reconstruction algorithm improves the reconstruction accuracy as well as the reconstruction time performance.FF-PIA and DCRNN clustering routing co-simulation reveals that the proposed algorithm can effectively improve the performance in extending the network lifetime and reducing data transmission delay.展开更多
On 5 March,2025,the"Spring Blossoms"ASEAN-China Lady Cultural Gathering was held at the White Pagoda Academy in Beijing.The event was co-hosted by the ASEAN-China Centre and the Beijing People's Associat...On 5 March,2025,the"Spring Blossoms"ASEAN-China Lady Cultural Gathering was held at the White Pagoda Academy in Beijing.The event was co-hosted by the ASEAN-China Centre and the Beijing People's Association for Friendship with Foreign Countries.展开更多
This is a case study of the application of pre-stack inverted elastic parameters to tight-sand reservoir prediction. With the development of oil and gas exploration, pre-stack data and inversion results are increasing...This is a case study of the application of pre-stack inverted elastic parameters to tight-sand reservoir prediction. With the development of oil and gas exploration, pre-stack data and inversion results are increasingly used for production objectives. The pre-stack seismic property studies include not only amplitude verse offset （AVO） but also the characteristics of other elastic property changes. In this paper, we analyze the elastic property parameters characteristics of gas- and wet-sands using data from four gas-sand core types. We found that some special elastic property parameters or combinations can be used to identify gas sands from water saturated sand. Thus, we can do reservoir interpretation and description using different elastic property data from the pre-stack seismic inversion processing. The pre- stack inversion method is based on the simplified Aki-Richard linear equation. The initial model can be generated from well log data and seismic and geologic interpreted horizons in the study area. The input seismic data is angle gathers generated from the common reflection gathers used in pre-stack time or depth migration. The inversion results are elastic property parameters or their combinations. We use a field data example to examine which elastic property parameters or combinations of parameters can most easily discriminate gas sands from background geology and which are most sensitive to pore-fluid content. Comparing the inversion results to well data, we found that it is useful to predict gas reservoirs using λ, λρ, λ/μ, and K/μ properties, which indicate the gas characteristics in the study reservoir.展开更多
Angle-domain common-image gathers（ADCIGs） are the basic data in migration velocity analysis（MVA） and amplitude variation with angle（AVA） analysis. We propose a common-angle gather-generating scheme using Kirchho...Angle-domain common-image gathers（ADCIGs） are the basic data in migration velocity analysis（MVA） and amplitude variation with angle（AVA） analysis. We propose a common-angle gather-generating scheme using Kirchhoff PSDM based on the traveltime gradient field. The scheme includes three major operations：（1） to calculate the traveltime field of the source and the receiver based on the dynamic programming approach;（2） to obtain the refl ection angle according to the traveltime gradient field in the image space; and（3） to generate the ADCIGs during the migration process. Because of the computation approach, the method for generating ADCIGs is superior to conventional ray-based methods. We use the proposed ADCIGs generation method in 3D large-scale seismic data. The key points of the method are the following.（1） We use common-shot datasets for migration,（2） we load traveltimes based on the shot aperture, and（3） we use the MPI and Open Mp memory sharing to decrease the amount of input and output（I/O）. Numerical examples using synthetic data suggest that the ADCIGs improve the quality of the velocity and the effectiveness of the 3D angle-gather generation scheme.展开更多
基金supported by PetroChina Coalbed Methane Co.,Ltd.
文摘With the maturation of coalbed methane(CBM)exploitation and the transition into the late stages of dewatering and gas production,liquid loading in gathering pipelines has emerged as a major constraint on productivity and operational stability.Based on real-time field data and gas-liquid physicochemical analyses,this study elucidates the mechanisms governing liquid loading formation under varying temperature,pressure,and water saturation conditions.An HYSYS model is employed to determine the water dew point,while the Turner model is used to evaluate the critical conditions for liquid holdup.The results indicate that gas water saturation exerts the dominant influence on liquid loading risk,followed by pressure,whereas temperature plays a comparatively minor role.When water saturation exceeds 2%and the operating temperature falls below the dew point,condensation-driven liquid loading increases sharply.To further characterize the spatial distribution of liquid accumulation,a steady-state OLGA model of a DN100 gathering pipeline network is developed to examine the effects of pipe diameter,water saturation,and soil temperature.The simulations show that larger pipe diameters and higher water saturation significantly aggravate liquid holdup,while elevated soil temperature mitigates liquid accumulation.Moreover,the liquid holdup ratio is found to correlate closely with flow regime transitions,confirming its suitability as a key indicator of liquid loading risk.Based on these findings,optimization strategies for pipeline design and operation are proposed.To mitigate liquid loading,the gathering pipeline velocity should be maintained above the critical value of 1.63 m/s,and the gas water content should be strictly controlled below 2%.Under operating conditions representative of the Hancheng block,it is recommended to reduce the pipeline diameter from DN130 to DN100 to enhance self-cleaning capacity.In addition,thermal insulation should be applied during winter operation to maintain the pipe wall temperature above 10◦C,thereby suppressing condensation-induced liquid accumulation.
基金supported by the National 863 Program (Grant No.2006AA06Z206,Sustained supported)the National Science and Technology Major Project (Grant No.2008ZX05006-004)SinoPec Group Marine Facies Research (Grant No.08370502000410)
文摘Pre-stack depth migration velocity analysis is one of the keys to influencing the imaging quality of pre-stack migration.In this paper we cover a residual curvature velocity analysis method on angle-domain common image gathers（ADCIGs） which can depict the relationship between incident angle and migration depth at imaging points and update the migration velocity.Differing from offset-domain common image gathers（ODCIGs）,ADCIGs are not disturbed by the multi-path problem which contributes to imaging artifacts,thus influencing the velocity analysis.On the basis of horizontal layers,we derive the residual depth equation and also propose a velocity analysis workflow for velocity scanning.The tests to synthetic and field data prove the velocity analysis methods adopted in this paper are robust and valid.
基金This study is jointly supported by the National Key R&D Program of China(2017YFC1500303 and 2020YFA0710604)the Science Foundation of China University of Petroleum,Beijing(2462019YJRC007 and 2462020YXZZ047)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-05).
文摘Reverse Time Migration(RTM)Surface Ofset Gathers(SOGs)are demonstrated to deliver more superior residual dip information than ray-based approaches.It appears more powerful in complex geological settings,such as salt areas.Still,the computational cost of constructing RTM SOGs is a big challenge in applying it to 3D feld data.To tackle this challenge,we propose a novel method using dips of local events as a guide for RTM gather interpolation.The residual-dip information of the SOGs is created by connecting local events from depth-domain to time-domain via ray tracing.The proposed method is validated by a synthetic experiment and a feld example.It mitigates the computational cost by an order of magnitude while producing comparable results as fully computed RTM SOGs.
基金supported by Financially Supported by Qingdao National Laboratory for Marine Science and Technology(No.QNLM2016ORP0206)National Science and Technology Major Project(No.2016ZX05027-002)+6 种基金China Postdoctoral Science Foundation(No.2017M612219)National Key R&D Plan(Nos.2017YFC0306706 and 2017YFC0307400)Financially Supported by Qingdao National Laboratory for Marine Science and Technology(No.QNLM201708)Natural Science Foundation of Shandong Province(No.ZR2016DB10)National Natural Science Foundation of China(Nos.41674118,41504109,and 41506084)Key Laboratory of Submarine Geosciences Foundation of SOA(No.KLSG1603)Qingdao Municipal Applied Research Projects(No.2016238)
文摘Angle-domain common-image gathers （ADCIGs） transformed from the shot- domain common-offset gathers are input to migration velocity analysis （MVA） and prestack inversion. ADCIGs are non-illusion prestack inversion gathers, and thus, accurate. We studied the extraction of elastic-wave ADCIGs based on amplitude-preserving elastic-wave reverse- time migration for calculating the incidence angle of P- and S-waves at each image point and for different source locations. The P- and S-waves share the same incident angle, namely the incident angle of the source P-waves. The angle of incidence of the source P-wavefield was the difference between the source P-wave propagation angle and the reflector dips. The propagation angle of the source P-waves was obtained from the polarization vector of the decomposed P-waves. The reflectors＇ normal direction angle was obtained using the complex wavenumber of the stacked reverse-time migration （RTM） images. The ADCIGs of P- and S-waves were obtained by rearranging the common-shot migration gathers based on the incident angle. We used a horizontally layered model, the graben medium model, and part of the Marmousi-II elastic model and field data to test the proposed algorithm. The results suggested that the proposed method can efficiently extract the P- and S-wave ADCIGs of the elastic-wave reverse-time migration, the P- and S-wave incident angle, and the angle-gather amplitude fidelity, and improve the MVA and prestack inversion.
基金the Natural Science Foundation of China(No.41804100)the China Postdoctoral Science Foundation(No.2018M640910)the Fundamental Research Funds for the Central Universities(No.2682018CX36)。
文摘Kirchhoff beam migration is a simplified Gaussian beam migration,which omits the dynamic information and can calculate multi-arrival traveltime,so it is a high-precision and fast seismic imaging method.In the imaging process,extracting common image gathers can be used for velocity analysis,improving the accuracy of modeling and imaging quality.Compared with the conventional common image gathers extracting methods,the angle-domain common image gathers extracting method can avoid the artifacts caused by multi-arrival seismic waves.The authors present a new method of extracting common image gathers in angle-domain from Kirchhoff beam migration and verify the method by numerical calculations.
基金supported by the National Key R&D Program of China(2020YFA0710604 and 2017YFC1500303)the Science Foundation of the China University of Petroleum,Beijing(2462019YJRC007 and 2462020YXZZ047)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-05).
文摘Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transform or low-rank approximation,which requires much computation.Based on an anisotropic-Helmholtz P/S wave-mode decomposition method,we propose a novel and efficient approach to produce angle-domain common-image gathers(ADCIGs)in the elastic reverse time migration(ERTM)of VTI media.To start with,we derive an anisotropic-Helmholtz decomposition operator from the Christoffel equation in VTI media,and use this operator to derive the decomposed formulations for anisotropic P/S waves.Second,we employ the first-order Taylor expansion to calculate the normalized term of decomposed formulations and obtain the anisotropic-Helmholtz decomposition method,which generates the separated P/S wavefields with correct amplitudes and phases.Third,we develop a novel way that uses the anisotropic-Helmholtz decomposition operator to define the polari-zation angles for anisotropic P/S waves and substitute these angles to decomposing formulations.The polarization angles are then calculated directly from the separated vector P-and S-wavefields and converted to the phase angles.The ADCIGs are thusly produced by applying the phase angles to VTI ERTM.In addition,we develop a concise approximate expression of residual moveout(RMO)for PP-reflections of flat reflectors in VTI media,which avoids the complex transformations between the group angles and the phase angles.The approximate RMO curves show a good agreement with the exact solution and can be used as a tool to assess the migration velocity errors.As demonstrated by two selected examples,our ADCIGs not only produce the correct kinematic responses with regards to different velocity pertubatation,but also generate the reliable amplitude responses versus different angle.The final stacking images of ADCIGs data exhibit the identical imaging effect as that of VTI ERTM.
基金financial support jointly provided by the National Key R&D Program of China under contract number 2019YFC0605503Cthe Major Projects during the 14th Five-year Plan period under contract number 2021QNLM020001+2 种基金the National Outstanding Youth Science Foundation under contract number 41922028the Funds for Creative Research Groups of China under contract number 41821002the Major Projects of CNPC under contract number ZD2019-183-003。
文摘The dip-angle-domain common-image gather(DDCIG)is a key tool to separate the diffraction and reflection imaging results.Reflectors with different spatial geometries produce different responses in DDCIGs.Compared with Kirchhoff migration,Gaussian beam migration(GBM)is more effective and robust to overcome the multipathing problem.As a ray-based method,it has explicit angle information naturally during the propagation.We have developed a 3D DDCIG computational method using GBM,which obtain both the imaging result and angle-domain gathers with only one pass of calculation.The angle-gather computation is based on geometrical optics,and multiple angle conversions are implemented under the rules of space geometry,which helps to avoid rounding errors and improve accuracy.Additionally,the multi-azimuth joint presentation strategy is proposed to describe the characteristic of omnidirectional dip angles using a finite number of gathers.After using a 2D model to illustrate application advantages of DDCIG,we apply the proposed method to two 3D models to test its feasibility and accuracy.A field data example further demonstrates the adaptability of our method to seismic imaging for a land survey.
基金sponsored by the National Natural Science Foun-dation of China(No.41974160,41774192,41430323).
文摘The hydrocarbon detection method based on pre-stack gather data has higher accuracy and reliability than those methods based on post-stack data.This kind of method requires that pre-stack gather data have high SNR(Signal Noise Ratio)and obvious AVO(amplitude variation with offset)characteristics.Therefore,it is important to optimize the pre-stack gathers and enhance their AVO(Amplitude variation with offset)effect.This abstract proposes a gather optimization and AVO feature enhanced method for hydrocarbon detection.The gather optimization method based on the improved BEMD(bidimensional empirical mode decomposition).It starts from the original signal directly,and can be optimized as pre-stack gather steadily and quickly.Then,the characters of CTKEO(Corss Teager-Kaiser energy)algorithm which is strong sensitivity to interaction of two signals is fully utilized to enhance AVO features.The method proposed in this abstract provides a good data base for pre-stack inversion from gather optimization to AVO feature enhancement.
文摘一、请根据录音,填写单词。二、听对话,选择正确的答案。1.Who is coming for dinner?A.Friends.B.Aunt and uncle.C.Grandma and grandpa.2.What does Dad offer to do at the beginning?A.Go shopping.B.Set the table.C.Cook the fish.
基金sponsored by Natural Science Foundation of Xinjiang Uygur Autonomous Region(2024D01A19).
文摘Research on mass gathering events is critical for ensuring public security and maintaining social order.However,most of the existing works focus on crowd behavior analysis areas such as anomaly detection and crowd counting,and there is a relative lack of research on mass gathering behaviors.We believe real-time detection and monitoring of mass gathering behaviors are essential formigrating potential security risks and emergencies.Therefore,it is imperative to develop a method capable of accurately identifying and localizing mass gatherings before disasters occur,enabling prompt and effective responses.To address this problem,we propose an innovative Event-Driven Attention Network(EDAN),which achieves image-text matching in the scenario of mass gathering events with good results for the first time.Traditional image-text retrieval methods based on global alignment are difficult to capture the local details within complex scenes,limiting retrieval accuracy.While local alignment-based methods aremore effective at extracting detailed features,they frequently process raw textual features directly,which often contain ambiguities and redundant information that can diminish retrieval efficiency and degrade model performance.To overcome these challenges,EDAN introduces an Event-Driven AttentionModule that adaptively focuses attention on image regions or textual words relevant to the event type.By calculating the semantic distance between event labels and textual content,this module effectively significantly reduces computational complexity and enhances retrieval efficiency.To validate the effectiveness of EDAN,we construct a dedicated multimodal dataset tailored for the analysis of mass gathering events,providing a reliable foundation for subsequent studies.We conduct comparative experiments with other methods on our dataset,the experimental results demonstrate the effectiveness of EDAN.In the image-to-text retrieval task,EDAN achieved the best performance on the R@5 metric,while in the text-to-image retrieval task,it showed superior results on both R@10 and R@5 metrics.Additionally,EDAN excelled in the overall Rsummetric,achieving the best performance.Finally,ablation studies further verified the effectiveness of event-driven attention module.
基金partially supported by the National Natural Science Foundation of China(62161016)the Key Research and Development Project of Lanzhou Jiaotong University(ZDYF2304)+1 种基金the Beijing Engineering Research Center of Highvelocity Railway Broadband Mobile Communications(BHRC-2022-1)Beijing Jiaotong University。
文摘In order to solve the problems of short network lifetime and high data transmission delay in data gathering for wireless sensor network(WSN)caused by uneven energy consumption among nodes,a hybrid energy efficient clustering routing base on firefly and pigeon-inspired algorithm(FF-PIA)is proposed to optimise the data transmission path.After having obtained the optimal number of cluster head node(CH),its result might be taken as the basis of producing the initial population of FF-PIA algorithm.The L′evy flight mechanism and adaptive inertia weighting are employed in the algorithm iteration to balance the contradiction between the global search and the local search.Moreover,a Gaussian perturbation strategy is applied to update the optimal solution,ensuring the algorithm can jump out of the local optimal solution.And,in the WSN data gathering,a onedimensional signal reconstruction algorithm model is developed by dilated convolution and residual neural networks(DCRNN).We conducted experiments on the National Oceanic and Atmospheric Administration(NOAA)dataset.It shows that the DCRNN modeldriven data reconstruction algorithm improves the reconstruction accuracy as well as the reconstruction time performance.FF-PIA and DCRNN clustering routing co-simulation reveals that the proposed algorithm can effectively improve the performance in extending the network lifetime and reducing data transmission delay.
文摘On 5 March,2025,the"Spring Blossoms"ASEAN-China Lady Cultural Gathering was held at the White Pagoda Academy in Beijing.The event was co-hosted by the ASEAN-China Centre and the Beijing People's Association for Friendship with Foreign Countries.
基金supported by the National Basic Priorities Program "973" Project (Grant No.2007CB209600)China Postdoctoral Science Foundation Funded Project
文摘This is a case study of the application of pre-stack inverted elastic parameters to tight-sand reservoir prediction. With the development of oil and gas exploration, pre-stack data and inversion results are increasingly used for production objectives. The pre-stack seismic property studies include not only amplitude verse offset （AVO） but also the characteristics of other elastic property changes. In this paper, we analyze the elastic property parameters characteristics of gas- and wet-sands using data from four gas-sand core types. We found that some special elastic property parameters or combinations can be used to identify gas sands from water saturated sand. Thus, we can do reservoir interpretation and description using different elastic property data from the pre-stack seismic inversion processing. The pre- stack inversion method is based on the simplified Aki-Richard linear equation. The initial model can be generated from well log data and seismic and geologic interpreted horizons in the study area. The input seismic data is angle gathers generated from the common reflection gathers used in pre-stack time or depth migration. The inversion results are elastic property parameters or their combinations. We use a field data example to examine which elastic property parameters or combinations of parameters can most easily discriminate gas sands from background geology and which are most sensitive to pore-fluid content. Comparing the inversion results to well data, we found that it is useful to predict gas reservoirs using λ, λρ, λ/μ, and K/μ properties, which indicate the gas characteristics in the study reservoir.
基金funded by the National Basic Research Program of China(973 Program)(No.2011 CB201002)the National Natural Science Foundation of China(No.41374117)the great and special projects(No.2011ZX05003-003,2011ZX05005-005-008 HZ,and 2011ZX05006-002)
文摘Angle-domain common-image gathers（ADCIGs） are the basic data in migration velocity analysis（MVA） and amplitude variation with angle（AVA） analysis. We propose a common-angle gather-generating scheme using Kirchhoff PSDM based on the traveltime gradient field. The scheme includes three major operations：（1） to calculate the traveltime field of the source and the receiver based on the dynamic programming approach;（2） to obtain the refl ection angle according to the traveltime gradient field in the image space; and（3） to generate the ADCIGs during the migration process. Because of the computation approach, the method for generating ADCIGs is superior to conventional ray-based methods. We use the proposed ADCIGs generation method in 3D large-scale seismic data. The key points of the method are the following.（1） We use common-shot datasets for migration,（2） we load traveltimes based on the shot aperture, and（3） we use the MPI and Open Mp memory sharing to decrease the amount of input and output（I/O）. Numerical examples using synthetic data suggest that the ADCIGs improve the quality of the velocity and the effectiveness of the 3D angle-gather generation scheme.
