立体气枪阵列延迟激发震源特性及在浅海区OBS探测中的应用  

Tridimensional air-gun array with delay fired source signal characteristics and the application in OBS exploration in shallow seas

作　　者：吴志强[1,2,3] 郝天珧[4] 唐松华 张训华[1,2,3] 郑彦鹏[6] 肖国林[1,2,3] 赵维娜[7,2,3] 

机构地区：[1]国土资源部海洋油气资源与环境地质重点实验室,青岛266071 [2]青岛海洋地质研究所,青岛266071 [3]青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266000 [4]中国科学院地质与地球物理研究所,北京100029 [5]上海海洋石油局第一海洋地质调查大队,上海201200 [6]国家海洋局第一海洋研究所,青岛266061 [7]中国海洋大学,青岛266063

出　　处：《地球物理学报》2016年第7期2573-2586,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41210005;90814011);国家"863"计划项目(2009AA093401);国土资源部地质调查专项(GZH200800503;GZH201200509)联合资助

摘　　要：利用中、小容量气枪组成的立体气枪阵列延迟激发震源和海底地震仪(OBS)在我国北部浅海海域开展了人工地震深部地球物理探测试验.基于水深条件和压制水体虚反射、提升低频能量的需要,使气枪震源有足够的输出能量和高品质子波特性,研究了立体气枪阵列延迟激发震源工作机理,经远场子波理论模拟优选了组合参数并进行了海上试验工作.结果表明,中、小容量气枪组成的立体气枪阵列延迟激发震源,适应了浅水海域的激发环境,降低了由虚反射造成的局部陷波和干扰作用,有效地改善了OBS信号的品质,获得了Ps,Pg,PmP,Pn等多种震相.创新了由中、小容量气枪组成的立体气枪阵列延迟激发震源在浅海区OBS探测中的应用,也填补了南黄海海域深地震探测数据的空白,为南黄海、渤海深部地壳结构研究及含油气盆地形成演化研究提供了重要的基础资料.The Bohai Sea is in the North China block and the South Yellow Sea is located in theYangtze block. These seas are rich in oil and gas resources, related with block convergence and plate movement. The aim is to carry out seismic deep OBS detection in the Southern Yellow Sea and the Bohai Sea to get the seismic reflection and refraction information of lithosphere and the Moho surface for the study on the crust-mantle structure characteristics, the contact relation of the North China block and the Yangtze block and the tectonic effect of the plate movement and its control on the basin formation, evolution and hydrocarbon accumulation. The deep crust OBS exploration in the deep sea uses a conventional air-gun array which is made of several sub-arrays each containing a number of large volume air-guns. But in the shallow sea, it is difficult to play an effective role due to the gun depth limit and serious seafloor ghost reflection and source water ghost. To meet the needs for attenuation of water ghost reflection and enhancement of the low frequency content of seismic wavelet, based on the water depth condition and analysis of the principle of multi-level air-gun array and delay fired source applied in oil and gas exploration in the deep sea, we develop a method to delay the sub-array fired time for the tridimensional air-gun array source composed of a number of smaller volume air-guns. Compared with the multi-levels air-gun array, we apply a smaller depth difference and flexible sub-array sinking for sub air-gun array in order to adapt to the harsh environment for shooting the air-gun in the shallow water, thus we can get better effect for bubble suppression and ghost attenuation. A pattern of flexible delay fired time is designed for improving to output energy of the source and the quality of the wavelet. We design different combination schemes for tridimensional air-gun array and delay fired source and model its far-field wavelets. The amplitude-frequence distribution of our designed tridimensional air-gun array wit

关 键 词：立体气枪阵列 远场子波 OBS深部探测 虚反射压制 浅海区 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]