The methods of estimating the minimum allowed value of IFOV (instantaneous field of view) of the detector in a rosette scan system are investigated. The common method for the estimation of IFOV is described. A new met...The methods of estimating the minimum allowed value of IFOV (instantaneous field of view) of the detector in a rosette scan system are investigated. The common method for the estimation of IFOV is described. A new method which uses the maximum distance between two neighboring petals as the estimated value of IFOV is developed and a comparison between the common method and the new method is given. It is concluded that the minimum allowed value of IFOV of rosette scanning is over estimated by the common method while this value can be calculated accurately with the new method.展开更多
To study the measurement of distance under the condition of the frequency modulation (FM) multi component signal of a short range radar, the multi points scattering model of a target, the TLS ESPRIT (total least sq...To study the measurement of distance under the condition of the frequency modulation (FM) multi component signal of a short range radar, the multi points scattering model of a target, the TLS ESPRIT (total least square estimation of signal parameters via rotational invariance techniques) and the mathematical statistics methods were used. The method of computing single frequency signal's instantaneous frequency (IF) is unsuitable to the multi component signal. By using the method of the TLS ESPRIT combined with the mathematical statistics, the multi component signal's IF can be obtained. The computer simulation has shown that the method has the high accuracy for measuring the distance.展开更多
Studied the principle of transient electromagnetic method in coalmine and solved the computation of the whole time apparent resistivity and the relation between apparent resistivity and exploration depth and so on. St...Studied the principle of transient electromagnetic method in coalmine and solved the computation of the whole time apparent resistivity and the relation between apparent resistivity and exploration depth and so on. Studied the work method of transient electromagnetic method in coalmine and obtained reasonable arrangement way. Studied data processing and explanation method of transient electromagnetic method and obtained high quality electric section. Finally the purpose to detect water-bearing body and water-bearing structure in front of roadway in advance, and detect the water-bearing property of the roof and floor rock layer of coal face were realized by use of transient electromagnetic method.展开更多
For some time, whole space feature as a theoretical problem has been a puzzle in mining transient electromagnetic method （TEM）. We have introduced a detailed method of calculating the transient response of a vertica...For some time, whole space feature as a theoretical problem has been a puzzle in mining transient electromagnetic method （TEM）. We have introduced a detailed method of calculating the transient response of a vertical magnetic bipolar source in a whole space plane layered medium in order to obtain whole space features. After designing a whole space plane layered medium model, equations were established based on boundary conditions in terms of electromagnetic vector potential. Expressions of electromagnetic fields were obtained by solving these equations. The expressions were computed by the Hankel transform after dispersion. The results in a frequency domain were changed into a time domain by using a multinomial cosine transform method. The expressions were correctly validated by comparing them with the analytical solution in half space. The half space and whole space results show that the whole space features are dear, suggesting that the theory of half space is not suitable for the whole space. Our algorithm supplied the technical instrument for studying the distributed features of whole space transient electromagnetic fields.展开更多
To overcome the shortcomings of the traditional multibeam survey and data processing, a new method is presented for the precise determination of the instantaneous height at the multibeam transducer by the blend of GPS...To overcome the shortcomings of the traditional multibeam survey and data processing, a new method is presented for the precise determination of the instantaneous height at the multibeam transducer by the blend of GPS height and heave signals. Before signal blend, GPS height and heave signals need to be corrected first to the transducer center by attitude correction. Second, the GPS height needs to be checked and modified by heave check and modification itself. Butterworth and FFT （fast Fourier transformation） were used in the signal blend. Finally, FFT is thought to be appropriate in signal processing. The new method efficiently overcomes the shortcomings of the traditional method, and this is proven well by the MBS （multibeam bathymetric system） experiment.展开更多
The accurate monitor and prediction of fracturing pressure for formation is very important to hydraulic fracturing treatment operation, but whether hydraulic fracturing is successful or not, the fracturing fluid plays...The accurate monitor and prediction of fracturing pressure for formation is very important to hydraulic fracturing treatment operation, but whether hydraulic fracturing is successful or not, the fracturing fluid plays a very important role, leak-off coefficient is the most leading parameters of fracturing fluids. Mini-frac test was the most commonly used tools for leak-off coefficient analysis, but it has the shortcoming of time-consuming and costly that can not meet the requirement of the production. The main purpose of this paper is to introduce a simple and convenient leak off coefficient analysis method with more inexpensive and time-saving than former methods. Based on ISIP （instantaneous shut-in pressure） method, a new field method of leak off coefficient field analysis model was presented. According to twice ISIP of the fracturing treatment in field operation, therefore, fluid leak off coefficient and formation characteristic can be studied quickly and reliably. More than 40 wells were fractured using this field method. The results show that average liquid rates of post-fracturing was 20 m3/d which double improvement compared with the past treatment wells. It had an important role for fracturing treatments in low permeability used in field application. reservoirs, the new model for real time analysis and adjust is successful展开更多
Higher-order Time Domain Finite Element Method (TDFEM) based on the nodal inter- polation is proposed for two-dimensional electromagnetic analysis. The detailed algorithms of the method are presented firstly, and then...Higher-order Time Domain Finite Element Method (TDFEM) based on the nodal inter- polation is proposed for two-dimensional electromagnetic analysis. The detailed algorithms of the method are presented firstly, and then the accuracy, CPU time and memory consumption of the higher-order node-based TDFEM are investigated. The high performance of the presented approach is validated by numerical results of the transient responses of Transverse Electric (TE) field and Transverse Magnetic (TM) field in a rectangular waveguide.展开更多
文摘The methods of estimating the minimum allowed value of IFOV (instantaneous field of view) of the detector in a rosette scan system are investigated. The common method for the estimation of IFOV is described. A new method which uses the maximum distance between two neighboring petals as the estimated value of IFOV is developed and a comparison between the common method and the new method is given. It is concluded that the minimum allowed value of IFOV of rosette scanning is over estimated by the common method while this value can be calculated accurately with the new method.
基金Doctoral Programme Foundation of Institution of Higher Education of China.
文摘To study the measurement of distance under the condition of the frequency modulation (FM) multi component signal of a short range radar, the multi points scattering model of a target, the TLS ESPRIT (total least square estimation of signal parameters via rotational invariance techniques) and the mathematical statistics methods were used. The method of computing single frequency signal's instantaneous frequency (IF) is unsuitable to the multi component signal. By using the method of the TLS ESPRIT combined with the mathematical statistics, the multi component signal's IF can be obtained. The computer simulation has shown that the method has the high accuracy for measuring the distance.
文摘Studied the principle of transient electromagnetic method in coalmine and solved the computation of the whole time apparent resistivity and the relation between apparent resistivity and exploration depth and so on. Studied the work method of transient electromagnetic method in coalmine and obtained reasonable arrangement way. Studied data processing and explanation method of transient electromagnetic method and obtained high quality electric section. Finally the purpose to detect water-bearing body and water-bearing structure in front of roadway in advance, and detect the water-bearing property of the roof and floor rock layer of coal face were realized by use of transient electromagnetic method.
基金Project 40674074 supported by the National Natural Science Foundation of China
文摘For some time, whole space feature as a theoretical problem has been a puzzle in mining transient electromagnetic method （TEM）. We have introduced a detailed method of calculating the transient response of a vertical magnetic bipolar source in a whole space plane layered medium in order to obtain whole space features. After designing a whole space plane layered medium model, equations were established based on boundary conditions in terms of electromagnetic vector potential. Expressions of electromagnetic fields were obtained by solving these equations. The expressions were computed by the Hankel transform after dispersion. The results in a frequency domain were changed into a time domain by using a multinomial cosine transform method. The expressions were correctly validated by comparing them with the analytical solution in half space. The half space and whole space results show that the whole space features are dear, suggesting that the theory of half space is not suitable for the whole space. Our algorithm supplied the technical instrument for studying the distributed features of whole space transient electromagnetic fields.
基金Funded by the National Natural Science Foundation of China （No.40776048）
文摘To overcome the shortcomings of the traditional multibeam survey and data processing, a new method is presented for the precise determination of the instantaneous height at the multibeam transducer by the blend of GPS height and heave signals. Before signal blend, GPS height and heave signals need to be corrected first to the transducer center by attitude correction. Second, the GPS height needs to be checked and modified by heave check and modification itself. Butterworth and FFT （fast Fourier transformation） were used in the signal blend. Finally, FFT is thought to be appropriate in signal processing. The new method efficiently overcomes the shortcomings of the traditional method, and this is proven well by the MBS （multibeam bathymetric system） experiment.
文摘The accurate monitor and prediction of fracturing pressure for formation is very important to hydraulic fracturing treatment operation, but whether hydraulic fracturing is successful or not, the fracturing fluid plays a very important role, leak-off coefficient is the most leading parameters of fracturing fluids. Mini-frac test was the most commonly used tools for leak-off coefficient analysis, but it has the shortcoming of time-consuming and costly that can not meet the requirement of the production. The main purpose of this paper is to introduce a simple and convenient leak off coefficient analysis method with more inexpensive and time-saving than former methods. Based on ISIP （instantaneous shut-in pressure） method, a new field method of leak off coefficient field analysis model was presented. According to twice ISIP of the fracturing treatment in field operation, therefore, fluid leak off coefficient and formation characteristic can be studied quickly and reliably. More than 40 wells were fractured using this field method. The results show that average liquid rates of post-fracturing was 20 m3/d which double improvement compared with the past treatment wells. It had an important role for fracturing treatments in low permeability used in field application. reservoirs, the new model for real time analysis and adjust is successful
基金Supported by National Natural Science Foundation of China (No. 60601024)
文摘Higher-order Time Domain Finite Element Method (TDFEM) based on the nodal inter- polation is proposed for two-dimensional electromagnetic analysis. The detailed algorithms of the method are presented firstly, and then the accuracy, CPU time and memory consumption of the higher-order node-based TDFEM are investigated. The high performance of the presented approach is validated by numerical results of the transient responses of Transverse Electric (TE) field and Transverse Magnetic (TM) field in a rectangular waveguide.
