对三种舞动幅值的计算方法进行比较,提出采用气象系数法确定导线各个舞动阶次的幅值。以正弦驻波作为导线舞动激励,分别采用线长法、能量法和有限元法(finite element analysis,FEA)计算孤立档导线舞动张力变化值:线长法与有限元法计算...对三种舞动幅值的计算方法进行比较,提出采用气象系数法确定导线各个舞动阶次的幅值。以正弦驻波作为导线舞动激励,分别采用线长法、能量法和有限元法(finite element analysis,FEA)计算孤立档导线舞动张力变化值:线长法与有限元法计算结果基本一致;能量法计算值小于线长法和有限元法,舞动半波数为奇数时,其计算值为其他方法计算值的40%～50%。通过在通用有限元软件ANSYS中建立包含2个独立耐张段和1个独立耐张段的连续多档有限元模型,分析不同档数下耐张塔和直线塔两侧导线舞动张力差的变化规律。分析结果表明:当数不小于4时,档数变化对铁塔两侧导线舞动张力及张力差的影响不大,耐张塔挂点张力差可取两档模型理论计算值的50%;相同档数时,直线塔舞动张力差为耐张塔舞动张力差的12%～25%。基于舞动张力分析结果,提出了杆塔舞动荷载的计算方法。展开更多
A type of specific fractured hydrocarbon reservoir, a shale fractured reservoir, exists in the Shengli oilfield. Due to very small porosity of this type, low sensitivity to the variation of petrochemical property para...A type of specific fractured hydrocarbon reservoir, a shale fractured reservoir, exists in the Shengli oilfield. Due to very small porosity of this type, low sensitivity to the variation of petrochemical property parameters, and strong anisotropy, it is very difficult to explore for them. So far, there is no set of mature methods for recognition of direction, distribution, and density of the fractures by an integrated analysis of geologic, geophysical, well log, drilling data, and etc. This paper presents a new method for acoustic impedance variation with azimuth （IPVA）, based on existing fracture detection methods. Seismic acquisition, processing, and recognition techniques were developed for detecting directional vertical fractures using multi-azimuth P wave data in combination with the seismic and geological features of shale fractures in the Luojia area. The IPVA research is carried out for recognizing the distribution, strike, and density of fractures based on the study of velocity variation with azimuth （VVA） and amplitude variation with azimuth （AVA） for full azimuth P wave data at different CMP positions. Through practical application in the Luojia area, primary results have been obtained which verifies that the IPVA method provides good potential for quantitative detection of parallel, high angle, shale fractures.展开更多
The field experiment is conducted from April 16, 2005 to July 20, 2005 at Wenchang area east of Hainan Island （19~35＇N, l12~E） of China. Internal wave packets are observed frequently with thermistor chains during t...The field experiment is conducted from April 16, 2005 to July 20, 2005 at Wenchang area east of Hainan Island （19~35＇N, l12~E） of China. Internal wave packets are observed frequently with thermistor chains during the experiment. Meanwhile, internal waves are also detected from a synthetic aperture radar （SAR） image on June 19, 2005 and several other moderate-resolution imaging spectroradiometer （MODIS） images near a mooring position. The distance between the positive and negative peaks induced by the internal wave can be obtained from satellite images. Combined with remote sensing images and in situ data, a new method to inverse the amplitude of the internal wave is proposed based on a corrected nonlinear Schr6dinger （NLS） equation. Two relationships are given between the peak-to-peak distance and the characteristic wavelength of the internal wave for different nonlinear and dispersion coefficients. Based on the satellite images, the amplitude inversion of the internal waves are carried out with the NLS equation as well as the KdV equation. The calculated amplitudes of the NLS equation are close to the observation amplitude which promise the NLS equation a reliable method.展开更多
The important parameters to describe waves are their amplitude and length.In order to make it easier to improve wave amplitude and facilitate wave experiment,a simple push-type wave generating method using digital rot...The important parameters to describe waves are their amplitude and length.In order to make it easier to improve wave amplitude and facilitate wave experiment,a simple push-type wave generating method using digital rotary valve control was proposed and different wave amplitudes were generated by the new method.After the mathematical model of the new method had been established,numerical analysis based on the linear wave theory was carried out by means of Matlab/Simulink software tools,and experiments were conducted on the push-type wave maker to ascertain the validity of the established model and the numerical simulation results.It shows that both experimental and theoretical results agree relatively well,and the plate motion frequency and amplitude of the push-type wave maker can be continuously adjusted and the various required regular waves can be obtained.Although the wave amplitude and length descends with the increasing of working frequency,the wave amplitude can be improved conveniently by setting the axial opening width of the valve and the oil supply pressure of system.The wave length remains unchanged with the axial opening width and the oil supply pressure change.The research indicates that different regular waves can be easily generated by the new method and the wave amplitude can be further improved in a certain plate motion frequency range.展开更多
In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsys...In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsystem,a dynamic loading subsystem,a specimen box subsystem,and a data measurement subsystem.The static loading subsystem uses low stiffness loss frame structure technology,which greatly improves the frame stiffness in the three principal stress directions(up to 20 GN/m)and ensures the demand of the disturbance experiment in both the prepeak and postpeak stages.The disturbance loads with frequency of 0e20 Hz and stress level of 0e30 MPa were applied using large flow parallel oil source technology characterized with high heat dissipation efficiency.For the disturbance loads with frequency of 100e500 Hz and stress level of 0e30 MPa,they were realized by using high-frequency and centimeter-per-second-scale low-speed disturbance rod technology.Three rigid self-stabilizing specimen boxes were utilized to provide support for the specimen and deformation sensors,ensuring the stability and accuracy of the data obtained.To verify the performance of the true triaxial test system,disturbance experiments were conducted on granite specimens.The results show that the experimental device satisfies the requirements of original design,with an excellent repeatability and reliable testing results.展开更多
文摘对三种舞动幅值的计算方法进行比较,提出采用气象系数法确定导线各个舞动阶次的幅值。以正弦驻波作为导线舞动激励,分别采用线长法、能量法和有限元法(finite element analysis,FEA)计算孤立档导线舞动张力变化值:线长法与有限元法计算结果基本一致;能量法计算值小于线长法和有限元法,舞动半波数为奇数时,其计算值为其他方法计算值的40%～50%。通过在通用有限元软件ANSYS中建立包含2个独立耐张段和1个独立耐张段的连续多档有限元模型,分析不同档数下耐张塔和直线塔两侧导线舞动张力差的变化规律。分析结果表明:当数不小于4时,档数变化对铁塔两侧导线舞动张力及张力差的影响不大,耐张塔挂点张力差可取两档模型理论计算值的50%;相同档数时,直线塔舞动张力差为耐张塔舞动张力差的12%～25%。基于舞动张力分析结果,提出了杆塔舞动荷载的计算方法。
文摘A type of specific fractured hydrocarbon reservoir, a shale fractured reservoir, exists in the Shengli oilfield. Due to very small porosity of this type, low sensitivity to the variation of petrochemical property parameters, and strong anisotropy, it is very difficult to explore for them. So far, there is no set of mature methods for recognition of direction, distribution, and density of the fractures by an integrated analysis of geologic, geophysical, well log, drilling data, and etc. This paper presents a new method for acoustic impedance variation with azimuth （IPVA）, based on existing fracture detection methods. Seismic acquisition, processing, and recognition techniques were developed for detecting directional vertical fractures using multi-azimuth P wave data in combination with the seismic and geological features of shale fractures in the Luojia area. The IPVA research is carried out for recognizing the distribution, strike, and density of fractures based on the study of velocity variation with azimuth （VVA） and amplitude variation with azimuth （AVA） for full azimuth P wave data at different CMP positions. Through practical application in the Luojia area, primary results have been obtained which verifies that the IPVA method provides good potential for quantitative detection of parallel, high angle, shale fractures.
基金The National Natural Science Foundation of China under contract Nos 61171161 and 61471136the National High Technology Research and Development Program(863 Program)of China under contract No.2013AA09A502
文摘The field experiment is conducted from April 16, 2005 to July 20, 2005 at Wenchang area east of Hainan Island （19~35＇N, l12~E） of China. Internal wave packets are observed frequently with thermistor chains during the experiment. Meanwhile, internal waves are also detected from a synthetic aperture radar （SAR） image on June 19, 2005 and several other moderate-resolution imaging spectroradiometer （MODIS） images near a mooring position. The distance between the positive and negative peaks induced by the internal wave can be obtained from satellite images. Combined with remote sensing images and in situ data, a new method to inverse the amplitude of the internal wave is proposed based on a corrected nonlinear Schr6dinger （NLS） equation. Two relationships are given between the peak-to-peak distance and the characteristic wavelength of the internal wave for different nonlinear and dispersion coefficients. Based on the satellite images, the amplitude inversion of the internal waves are carried out with the NLS equation as well as the KdV equation. The calculated amplitudes of the NLS equation are close to the observation amplitude which promise the NLS equation a reliable method.
基金Supported by National Natural Science Foundation of China(Grant Nos.51605431,51705456)Ningbo Municipal Natural Science Foundation of China(Grant No.2019A610162)Ningbo Major Scientific and Technological Projects(Grant No.2017C110005).
文摘The important parameters to describe waves are their amplitude and length.In order to make it easier to improve wave amplitude and facilitate wave experiment,a simple push-type wave generating method using digital rotary valve control was proposed and different wave amplitudes were generated by the new method.After the mathematical model of the new method had been established,numerical analysis based on the linear wave theory was carried out by means of Matlab/Simulink software tools,and experiments were conducted on the push-type wave maker to ascertain the validity of the established model and the numerical simulation results.It shows that both experimental and theoretical results agree relatively well,and the plate motion frequency and amplitude of the push-type wave maker can be continuously adjusted and the various required regular waves can be obtained.Although the wave amplitude and length descends with the increasing of working frequency,the wave amplitude can be improved conveniently by setting the axial opening width of the valve and the oil supply pressure of system.The wave length remains unchanged with the axial opening width and the oil supply pressure change.The research indicates that different regular waves can be easily generated by the new method and the wave amplitude can be further improved in a certain plate motion frequency range.
基金This study was financially supported by the National Natural Science Foundation of China(Grant No.51839003),for which we are grateful.
文摘In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsystem,a dynamic loading subsystem,a specimen box subsystem,and a data measurement subsystem.The static loading subsystem uses low stiffness loss frame structure technology,which greatly improves the frame stiffness in the three principal stress directions(up to 20 GN/m)and ensures the demand of the disturbance experiment in both the prepeak and postpeak stages.The disturbance loads with frequency of 0e20 Hz and stress level of 0e30 MPa were applied using large flow parallel oil source technology characterized with high heat dissipation efficiency.For the disturbance loads with frequency of 100e500 Hz and stress level of 0e30 MPa,they were realized by using high-frequency and centimeter-per-second-scale low-speed disturbance rod technology.Three rigid self-stabilizing specimen boxes were utilized to provide support for the specimen and deformation sensors,ensuring the stability and accuracy of the data obtained.To verify the performance of the true triaxial test system,disturbance experiments were conducted on granite specimens.The results show that the experimental device satisfies the requirements of original design,with an excellent repeatability and reliable testing results.
