浅地层剖面资料处理中的地层厚度校正(英文)
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摘要
浅地层剖面测量是海洋工程勘察、灾害地质调查和大陆架海洋地质科学研究的重要手段,资料解译的准确程度将对地质调查和研究成果的可靠性造成直接影响。由于发收分置型浅地层剖面仪的激发装置与接收装置是分开的,当调查区域的水深过浅时,将其近似为自激自收的单道地震系统会导致地层的畸变,水深越浅地层畸变率越大。根据浅地层剖面仪的基本原理,推导出了浅部地层厚度畸变校正公式,为用C-View软件更准确地解译此类浅地层剖面资料提供了参考。海底沉积物的声速直接影响浅地层剖面地层厚度解译的准确性,利用卢博等建立的适用于中国东南近海的声速经验公式,在某人工岛构造调查中,根据地质钻孔获取的孔隙度参数计算各沉积层的平均声速,建立相应的声速结构剖面,对地层厚度进行校正,取得较好的效果,用孔隙度预测声速的方法参数容易获取,能够提高浅地层剖面资料的解译精度,使地层的厚度更接近于实际,具有一定的实用意义。
The subbottom profiling is an important means of marine engineering survey, hazardous geology study and continental shelf scientific research. The accuracy of subbottom profile data interpretation has a direct impact on the research and investigation results. Because some of profilers’ transducer and hydrophone are separately installed, when the survey area is very shallow, distortion of shallow layers will be caused if it is seen as a self-excited and self-collected single-channel seismic system. According to the principle of subbottom profiler, the distortion correction formula is deduced and analyzed, providing actual value to using C-View software to interpret such subbottom profile data more accurately. In addition, the seabed sediments sound velocity is one of the key parameters when acquiring and processing the subbottom profile data. On the basis of comparing some sound velocity forecasting empirical equations, the LU Bo’s equation was considered the most appropriate to predict the seabed sediments, sound velocity at near-shore of China. In a survey of an artificial island site, the LU Bo’s equation and the porosity data obtained from geological drilling were utilized to predict the sediments sound velocity, and the sound velocity structure profile was plotted, which was applied in processing the subbottom profile data of the artificial island investigation. The method of using porosity data to predict sediments sound velocity in processing subbottom profile data can improve the interpretation accuracy and it’s of practical significance.
The subbottom profiling is an important means of marine engineering survey, hazardous geology study and continental shelf scientific research. The accuracy of subbottom profile data interpretation has a direct impact on the research and investigation results. Because some of profilers’ transducer and hydrophone are separately installed, when the survey area is very shallow, distortion of shallow layers will be caused if it is seen as a self-excited and self-collected single-channel seismic system. According to the principle of subbottom profiler, the distortion correction formula is deduced and analyzed, providing actual value to using C-View software to interpret such subbottom profile data more accurately. In addition, the seabed sediments sound velocity is one of the key parameters when acquiring and processing the subbottom profile data. On the basis of comparing some sound velocity forecasting empirical equations, the LU Bo’s equation was considered the most appropriate to predict the seabed sediments, sound velocity at near-shore of China. In a survey of an artificial island site, the LU Bo’s equation and the porosity data obtained from geological drilling were utilized to predict the sediments sound velocity, and the sound velocity structure profile was plotted, which was applied in processing the subbottom profile data of the artificial island investigation. The method of using porosity data to predict sediments sound velocity in processing subbottom profile data can improve the interpretation accuracy and it’s of practical significance.
引文
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[7] Orsi T H, Dunn D A. Sound velocity and related physical properties of fine-grained abyssal sediments from the Brazil Basin (South Atlantic Ocean) [J]. Acoustical Society of America, 1990, 88(3): 1 536 - 1 543.
[8] LU B. Model of sound velocity structure in seawater-sediments [J]. Marine Science Bulletin, 1995, 14(2): 42 - 47.
[9] LU B, LI G X, SUN D H, et al. Acoustic-physical properties of seafloor sediments from near shore southeast China and their correlations [J]. Journal of Tropical Oceanography, 2006, 25(2): 12 - 17.
[10] TANG Y L. The relationship between porosity of sea bed sediment and sound velocity [J]. Acta Oceanologica Sinica, 1998, 20(6): 39 - 43.
[11] LU B, LIANG Y B. The statistical correlation between marine sediments physical parameters and sound velocity along the southeast sea of China [J]. Science in China (B), 1994, 24(5): 556 - 560.
[2] ZHAO T H, ZHANG Z X, XU F. Analysis of Typical Problem for Shallow Acoustic Surveying in the Shallow Waters [J]. Computing Techniques for Geophysical and Geochemical Exploration, 2002, 24(3): 215 - 219.
[3] Hamilton E L, George S, Menard H W, et al. Acoustic and Other Physical Properties of Shallow-Water Sediments off San Diego [J]. Acoustical Society of America, 1956, 28(1).
[4] Hamilton E L. Geoacoustic Modeling of the Sea Floor [J]. Acoustical Society of America, 1980, 68: 1 313 - 1 340.
[5] Anderson R S. Statistical correlation of physical properties and sound velocity in sediments [A]. Physical of Sound in Marine Sediments [C]. NY: Plenum Press, 1974, 481 - 518.
[6] ZHOU Z Y, DU J C, ZHAO G C, et al. Measurement of seafloor sound velocity vertical distribution of South China Sea and Yellow Sea [J]. Acta Oceanologica Sinica, 1983, 5(5): 543 - 552.
[7] Orsi T H, Dunn D A. Sound velocity and related physical properties of fine-grained abyssal sediments from the Brazil Basin (South Atlantic Ocean) [J]. Acoustical Society of America, 1990, 88(3): 1 536 - 1 543.
[8] LU B. Model of sound velocity structure in seawater-sediments [J]. Marine Science Bulletin, 1995, 14(2): 42 - 47.
[9] LU B, LI G X, SUN D H, et al. Acoustic-physical properties of seafloor sediments from near shore southeast China and their correlations [J]. Journal of Tropical Oceanography, 2006, 25(2): 12 - 17.
[10] TANG Y L. The relationship between porosity of sea bed sediment and sound velocity [J]. Acta Oceanologica Sinica, 1998, 20(6): 39 - 43.
[11] LU B, LIANG Y B. The statistical correlation between marine sediments physical parameters and sound velocity along the southeast sea of China [J]. Science in China (B), 1994, 24(5): 556 - 560.
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