东海冲绳海槽陆坡天然气水合物的地震学研究
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摘要
本文通过对东海973航次在冲绳海槽取得的多道地震数据进行有针对性的特殊处理,形成一套针对天然气水合物地震学研究行之有效的处理思路,提高速度分析的精度和分辨能力,压制浅层多次波,资料在保持一定信噪比的基础上尽可能的提高分辨率,相对振幅处理以及用于AVO分析的预处理等.在此基础上对天然气水合物进行识别和预测,我们发现在冲绳海槽南部西侧槽坡附近以及海槽内部发育有一系列泥底辟构造,在这些底辟构造的顶部明显存在与天然气水合物赋存相关的地球物理特征,如似海底反射层(BSR)、与海底反射同相轴极性相反,BSR上方的振幅空白区以及BSR上下的速度异常.从该区域的地质背景资料分析,冲绳海槽不仅具有很高的沉积速率并且海槽西侧的断层活跃,提供了富含有机质的物源以及用于天然气运移的通道,有利于天然气水合物的形成.
973 survey is carried out on Okinawa trough and obtains multi-channel seismic data which are processed in a specific way.Therefore we work out an effective seismic way of processing Gas hydrafe.It enhances the precision of the velocity analysis,suppresses the shallow multiples and improves the resolution based on some S-N ratio.It also preserves relative amplitude and do essome preprocesses for AVO.We point out that there are a series of mud diaper structures in the west continental slope of the south Okinawa Trough and in the interior of the Okinawa Trough.The obvious geophysical characteristics of the gas hydrate,at the same time,such as bottom simulating reflector(BSR),polarity reversion,amplitude blank zone and velocity anomaly through the BSR,are found at the top of these diaper structures.According to the analysis of the geological background,the deposit velocity is higher at the Okinawa Trough and the faults are active at the west of the Okinawa Trough.This is not only benefiting for the formation of the gas hydrate but also provide the channels for the migration of the free gas. Okinawa Trough is the target area of the gas hydrate reservoir.
973 survey is carried out on Okinawa trough and obtains multi-channel seismic data which are processed in a specific way.Therefore we work out an effective seismic way of processing Gas hydrafe.It enhances the precision of the velocity analysis,suppresses the shallow multiples and improves the resolution based on some S-N ratio.It also preserves relative amplitude and do essome preprocesses for AVO.We point out that there are a series of mud diaper structures in the west continental slope of the south Okinawa Trough and in the interior of the Okinawa Trough.The obvious geophysical characteristics of the gas hydrate,at the same time,such as bottom simulating reflector(BSR),polarity reversion,amplitude blank zone and velocity anomaly through the BSR,are found at the top of these diaper structures.According to the analysis of the geological background,the deposit velocity is higher at the Okinawa Trough and the faults are active at the west of the Okinawa Trough.This is not only benefiting for the formation of the gas hydrate but also provide the channels for the migration of the free gas. Okinawa Trough is the target area of the gas hydrate reservoir.
引文
[1]唐勇,金翔龙,方银霞,等.冲绳海槽天然气水合物BSR的地震研究[J].海洋学报,2003,25(4):59~66.
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[9]Minshull T A,Singh S C,Westbrook G K.Seismic velocitystructure at a gas hydrate reflector,offshore western Colombi-a,from full waveform inversion[J],J.Geophys.Res.,1994,99:4715~4734.
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[11]金翔龙.东海海洋地质[M].北京:海洋出版社,1992:323~330.
[12]Yilmaz.地震数据处理[M].北京:石油工业出版社,1994.
[13]李松康,刘军荣,沙世锦.海上精细目标处理去噪技术应用研究[M].北京2004国际地球物理会议张贴论文
[14]吴律.-τP变换及应用[M].北京:石油工业出版社,1993:53~62.
[15]刘怀山,周正云.用于研究东海天然气水合物的地震资料处理方法[J].青岛海洋大学学报,2002,32(3):441~448.
[16]殷八斤,曾灏,杨在岩.AVO技术的理论与实践[M].北京:石油工业出版社,1995:191~217.
[2]钱建中,曾久岭.地震剖面上的天然气水合物识别方法[J].海洋石油,2002,113(3):54~59.
[3]马在田,耿建华,董良国,等.海洋天然气水合物的地震识别方法研究[J].海洋地质与第四纪地质,2002,22(1):1~8.
[4]Hyndman R D,Spence G D.A seismic study of methane hy-drate marine bottom simulating reflectors[J],J.Geophys.Res.,1992,97:6683~6698.
[5]宋海斌,松林修,杨胜雄,等.海洋天然气水合物的地球物理研究(II):地震方法[J].地球物理学进展,2001,16(3):110~118.
[6]宋海斌,松林修,仓本真一.西南海海槽地震资料处理及其似海底反射层特征[J].地球物理学报,2001,44(6):799~804.
[7]栾锡武,秦蕴珊,张训华等.东海陆坡及相邻槽底天然气水合物的稳定域分析[J].地球物理学报,2003,46(4):467~475.
[8]宋海斌,Matsubayashi O,Kuramotos I.天然气水合物似海底反射层的全波形反演[J].地球物理学报,46(1):42~46.
[9]Minshull T A,Singh S C,Westbrook G K.Seismic velocitystructure at a gas hydrate reflector,offshore western Colombi-a,from full waveform inversion[J],J.Geophys.Res.,1994,99:4715~4734.
[10]翟世奎,陈立蓉,张海启.冲绳海槽的岩浆作用与海底热液活动[M].北京:海洋出版社,2001.
[11]金翔龙.东海海洋地质[M].北京:海洋出版社,1992:323~330.
[12]Yilmaz.地震数据处理[M].北京:石油工业出版社,1994.
[13]李松康,刘军荣,沙世锦.海上精细目标处理去噪技术应用研究[M].北京2004国际地球物理会议张贴论文
[14]吴律.-τP变换及应用[M].北京:石油工业出版社,1993:53~62.
[15]刘怀山,周正云.用于研究东海天然气水合物的地震资料处理方法[J].青岛海洋大学学报,2002,32(3):441~448.
[16]殷八斤,曾灏,杨在岩.AVO技术的理论与实践[M].北京:石油工业出版社,1995:191~217.
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