Physical properties of sea water,such as salinity,temperature,density and acoustic velocity,could be demarcated through degradation of energy caused by water absorption,attenuation and other factors.To overcome the ch...Physical properties of sea water,such as salinity,temperature,density and acoustic velocity,could be demarcated through degradation of energy caused by water absorption,attenuation and other factors.To overcome the challenging difficulties in the quick monitoring of these physical properties,we have explored the high resolution marine seismic survey to instantly characterize them.Based on the unique wavefield propagating in the sea water,we have developed a new approach to suppress the noise caused by the shallow sea water disturbance and obtain useful information for estimating the sea water structure.This approach improves seismic data with high signal-to-noise ratio and resolution.The seismic reflection imaging can map the sea water structure acoustically.Combined with the knowledge of local water body structure profile over years,the instant model for predicting the sea water properties could be built using the seismic data acquired from the specially designed high precision marine seismic acquisition.This model can also be updated with instant observation and the complete data processing system.The present study has the potential value to many applications,such as 3D sea water monitoring,engineering evaluation,geological disaster assessment and environmental assessment.展开更多
Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- y...Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- ysis of multi-scales gyre of formation with 1-D continuous Dmey wavelet transform of log curve （GR） and I-D discrete Daubechies wavelet transform of log curve （Rt） all make the division of sequence interfaces more objec- tive and precise, which avoids the artificial influence with core analysis and the uncertainty with seismic data and core analysis.展开更多
The high-resolution shallow seismic technique can be used for more accurately prospecting the position and property of faults and for the preliminary study of fault activity.The author obtains many high quality stack ...The high-resolution shallow seismic technique can be used for more accurately prospecting the position and property of faults and for the preliminary study of fault activity.The author obtains many high quality stack time sections through the prospecting methods of different seismic sources,different group intervals and different observation systems on the Xiadian fault.These sections clearly display the stratum structure and the structure characteristics from several meters to several hundred meters of the Xiadian fault.The resolutions of the different seismic sources,different group intervals and different observing systems are obtained.The prospecting methods and work parameters applicable for goal stratum of different depths and different accuracy requirements are proposed through the analysis of the stack time sections.This lays a good foundation for raising the prospecting resolution of the fault position and the latest active time of the fault.展开更多
The dynamic range of the currently most widely used 24-bit seismic data acquisition devices is 10–20 d B lower than that of broadband seismometers, and this can affect the completeness of seismic waveform recordings ...The dynamic range of the currently most widely used 24-bit seismic data acquisition devices is 10–20 d B lower than that of broadband seismometers, and this can affect the completeness of seismic waveform recordings under certain conditions. However, this problem is not easy to solve because of the lack of analog to digital converter(ADC) chips with more than 24 bits in the market. In this paper, we propose a method in which an adder, an integrator, a digital to analog converter chip, a field-programmable gate array, and an existing low-resolution ADC chip are used to build a third-order 16-bit oversampling delta-sigma modulator. This modulator is equipped with a digital decimation filter, thus facilitating higher resolution and larger dynamic range seismic data acquisition. Experimental results show that, within the 0.1–40 Hz frequency range, the circuit board's dynamic range reaches 158.2 d B, its resolution reaches 25.99 bits, and its linearity error is below 2.5 ppm, which is better than what is achieved by the commercial 24-bit ADC chips ADS1281 and CS5371. This demonstrates that the proposed method may alleviate or even completely resolve the amplitude-limitation problem that so commonly occurs with broadband observation instruments during strong earthquakes.展开更多
基金the Natural Science Foundation of China(41176077)Subject of 973(2009CB219505)+2 种基金Natural Science Foundation of Shandong(ZR2010DM012)Basic Research Special Foundation of the Third Institute of Oceanography affiliated to the State Oceanic Administration(TIOSOA,2009004)the Science Research Project for the South China Sea of Ocean University of China for their financial support to this work
文摘Physical properties of sea water,such as salinity,temperature,density and acoustic velocity,could be demarcated through degradation of energy caused by water absorption,attenuation and other factors.To overcome the challenging difficulties in the quick monitoring of these physical properties,we have explored the high resolution marine seismic survey to instantly characterize them.Based on the unique wavefield propagating in the sea water,we have developed a new approach to suppress the noise caused by the shallow sea water disturbance and obtain useful information for estimating the sea water structure.This approach improves seismic data with high signal-to-noise ratio and resolution.The seismic reflection imaging can map the sea water structure acoustically.Combined with the knowledge of local water body structure profile over years,the instant model for predicting the sea water properties could be built using the seismic data acquired from the specially designed high precision marine seismic acquisition.This model can also be updated with instant observation and the complete data processing system.The present study has the potential value to many applications,such as 3D sea water monitoring,engineering evaluation,geological disaster assessment and environmental assessment.
文摘Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- ysis of multi-scales gyre of formation with 1-D continuous Dmey wavelet transform of log curve （GR） and I-D discrete Daubechies wavelet transform of log curve （Rt） all make the division of sequence interfaces more objec- tive and precise, which avoids the artificial influence with core analysis and the uncertainty with seismic data and core analysis.
基金supported by the project of "Experimental Exploration of Urban Active Faults" of the National Development and Reform Commission of China (20041138)
文摘The high-resolution shallow seismic technique can be used for more accurately prospecting the position and property of faults and for the preliminary study of fault activity.The author obtains many high quality stack time sections through the prospecting methods of different seismic sources,different group intervals and different observation systems on the Xiadian fault.These sections clearly display the stratum structure and the structure characteristics from several meters to several hundred meters of the Xiadian fault.The resolutions of the different seismic sources,different group intervals and different observing systems are obtained.The prospecting methods and work parameters applicable for goal stratum of different depths and different accuracy requirements are proposed through the analysis of the stack time sections.This lays a good foundation for raising the prospecting resolution of the fault position and the latest active time of the fault.
基金supported by the National Natural Science Foundation of China(Grant No.41404142)the National Science and Technology Support Plan Project(Grant No.2012BAF14B12)+1 种基金the Basic Research Projects of Institute of Earthquake Science,CEA(Grant Nos.2014IES0201,2011IES0203&2015IES0406)the Earthquake Monitoring and Prediction Project,CEA(Grant No.16A46ZX262)
文摘The dynamic range of the currently most widely used 24-bit seismic data acquisition devices is 10–20 d B lower than that of broadband seismometers, and this can affect the completeness of seismic waveform recordings under certain conditions. However, this problem is not easy to solve because of the lack of analog to digital converter(ADC) chips with more than 24 bits in the market. In this paper, we propose a method in which an adder, an integrator, a digital to analog converter chip, a field-programmable gate array, and an existing low-resolution ADC chip are used to build a third-order 16-bit oversampling delta-sigma modulator. This modulator is equipped with a digital decimation filter, thus facilitating higher resolution and larger dynamic range seismic data acquisition. Experimental results show that, within the 0.1–40 Hz frequency range, the circuit board's dynamic range reaches 158.2 d B, its resolution reaches 25.99 bits, and its linearity error is below 2.5 ppm, which is better than what is achieved by the commercial 24-bit ADC chips ADS1281 and CS5371. This demonstrates that the proposed method may alleviate or even completely resolve the amplitude-limitation problem that so commonly occurs with broadband observation instruments during strong earthquakes.
