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

doi:10.6038/cjg20160722

CORC > 自然资源部第一海洋研究所 > 自然资源部第一海洋研究所 > 业务部门 > 海洋地质与地球物理研究室

	Tridimensional air-gun array with delay fired source signal characteristics and the application in OBS exploration in shallow seas
	Wu Zhi-Qiang 1,2,3; Hao Tian-Yao 4; Tang Song-Hua 5; Zheng Xun-Hua 1,2,3; Zheng Yan-Peng 6; Xia Guo-Lin 1,2,3; Zhao Wei-Na 2,3,7
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2016-07
卷号	59 期号:7 页码:2573-2586
关键词	Tridimensional air-gun array source Delay fired source Far-field wavelet simulation OBS depth exploration Source ghost suppression Shallow sea
ISSN号	0001-5733
DOI	10.6038/cjg20160722
英文摘要	The Bohai Sea is in the North China block and the South Yellow Sea is located in the Yangtze 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 with delay fired source is more smooth than that of a conventional one, and more energy can be extended in the low frequency bands. Based on water depth conditions in the OBS exploration area, we applied respectively different tridimensional air-gun array and delay fired source pattern in the Bohai Sea and the Southern Yellow Sea. Compared with the deep crust OBS exploration using conventional large volume air-gun array in the Bohai Sea in 2012, the quality of the OBS data accquired by using new source is improved obviously, the seismic signal has a stronger amplitude, richer phase, higher resolution, better continuity and higher S/N ratio. The maximum propagation distance of source signal is over 150 km, which is more than that of the conventional large volume air-gun array. The deep crust OBS exploration which is the first one in the South Yellow Sea indicates the OBSs can record rich seismic phases including Ps,Pg,PmP and Pn both in the uplift areas where distributed the high velocity layers which had shielding effect on the seismic signals and the depression areas with large deposition thickness. The OBSs record quality is higher and the effective propagation distance of the air-gun signal is over 140 km. The deep crust OBS exploration test using tridimensional air-gun array with delay fired source technique shows that this method can generate seismic signals with long propagation distance and deep penetration in the shallow water, which can effectively suppress the source ghost effect and improve OBSs data quality.
WOS研究方向	Geochemistry & Geophysics
语种	中文
出版者	SCIENCE PRESS
WOS记录号	WOS:000379377100022
内容类型	期刊论文
源URL	[http://ir.fio.com.cn/handle/2SI8HI0U/3418]
专题	业务部门_海洋地质与地球物理研究室
作者单位	1.Minist Land & Resources, Qingdao Inst Marine Geol, Qingdao 266071, Peoples R China; 2.Minist Land & Resources, Key Lab Marine Hydrocarbon Resource & Environm Ge, Qingdao 266071, Peoples R China; 3.Qingdao Natl Oceanog Lab, Funct Lab Marine Mineral Resource Geol & Explorat, Qingdao 266000, Peoples R China; 4.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China; 5.Shanghai Offshore Petr Bur, Marine Geol Party 1, Shanghai 201200, Peoples R China; 6.State Oceam Adm Peoples Repub China, Inst Oceanog 1, Qingdao 266061, Peoples R China; 7.Ocean Univ China, Qingdao 266063, Peoples R China
推荐引用方式 GB/T 7714	Wu Zhi-Qiang,Hao Tian-Yao,Tang Song-Hua,et al. Tridimensional air-gun array with delay fired source signal characteristics and the application in OBS exploration in shallow seas[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2016,59(7):2573-2586.
APA	Wu Zhi-Qiang.,Hao Tian-Yao.,Tang Song-Hua.,Zheng Xun-Hua.,Zheng Yan-Peng.,...&Zhao Wei-Na.(2016).Tridimensional air-gun array with delay fired source signal characteristics and the application in OBS exploration in shallow seas.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,59(7),2573-2586.
MLA	Wu Zhi-Qiang,et al."Tridimensional air-gun array with delay fired source signal characteristics and the application in OBS exploration in shallow seas".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 59.7(2016):2573-2586.