研究海水温盐结构的反射地震方法
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摘要
在物理海洋学的研究中,利用CTD(Conductivity,Temperature and Depth sensors)测量方法研究海水温盐结构存在着获取数据时间长、数据横向精度低的缺点,而利用反射地震记录可以获得剖面上连续的水体温盐结构,弥补了传统方法的不足。反射地震方法研究海水温盐结构是个新的交叉学科方法,称为"地震海洋学"。由于海水水体的物性变化比地层物性变化小得多,造成海水水体的反射地震资料信噪比很低,各类干扰强烈,因而海水水体的反射地震资料处理也和常规地震资料处理方法有所不同。它处理的重点是振幅补偿,叠前去噪以及叠后处理。笔者通过对"十五"973项目在南海东北部采集的一条高分辨率多道反射地震测线的海水水体部分的地震数据进行处理,压制了强线性干扰波,获得了水体反射图像。地震叠加速度分析获取的3个CDP(Common Depth Point)的垂向速度从1540 m.s-1单调减小到1478 m.s-1,与CTD测量得到的速度变化趋势一致。
CTD(Conductivity,Temperature and Depth sensors) method is usually used to study ocean thermohaline structure in physical oceanography research.There are some disadvantages on the method,such as spending too long time to acquire data and low transverse precision.A new cross-discipline method called "Seismic oceanography",which remedies the disadvantages of conventional CTD method,is introduced in this paper to study ocean thermohaline structure by muti-channel seismic profile.Since the variation of physical properties of seawater mass is much smaller than that of substrate layer,its seismic data are of low signal-to-noise ration due to strong interfering waves.As a result,the seismic data processing in oceanography is somewhat different from that in geology.The key processing procedures include amplitude compensation,pre-stack noise suppression and post-stack processing.In a processing test to a "973 Project" survey line run during the last 5-year plan in the northeastern South China Sea,shot-induced strong linear bubble interfering waves are suppressed and clear reflection images of seawater mass are obtained.The vertical velocities at the 3 CDP(Common Depth Point) sites obtained by stacking velocity analysis decrease monotonously from 1540 m·s-1 to 1438 m·s-1.The trend of velocity variation agrees well with CTD measurements.
CTD(Conductivity,Temperature and Depth sensors) method is usually used to study ocean thermohaline structure in physical oceanography research.There are some disadvantages on the method,such as spending too long time to acquire data and low transverse precision.A new cross-discipline method called "Seismic oceanography",which remedies the disadvantages of conventional CTD method,is introduced in this paper to study ocean thermohaline structure by muti-channel seismic profile.Since the variation of physical properties of seawater mass is much smaller than that of substrate layer,its seismic data are of low signal-to-noise ration due to strong interfering waves.As a result,the seismic data processing in oceanography is somewhat different from that in geology.The key processing procedures include amplitude compensation,pre-stack noise suppression and post-stack processing.In a processing test to a "973 Project" survey line run during the last 5-year plan in the northeastern South China Sea,shot-induced strong linear bubble interfering waves are suppressed and clear reflection images of seawater mass are obtained.The vertical velocities at the 3 CDP(Common Depth Point) sites obtained by stacking velocity analysis decrease monotonously from 1540 m·s-1 to 1438 m·s-1.The trend of velocity variation agrees well with CTD measurements.
引文
[1]宋海斌,董崇志.直达波去除技术在地震海洋学中的应用[C]//中国地球物理年会2007.青岛:中国海洋大学出版社,2007:622—622.
[2]HOLBROOK W S,PARAMO P,PEARSE S,et al.Thermo-haline Fine Structure in an Oceanographic Front from Seis-mic Reflection Profiling[J].Science,2003,301:821—824.
[3]NANDI P,HOLBROOK W S,PEARSE S,et al.Seismicreflection imagine of water mass boundaries in the Norwe-gian Sea[J].Geophysical Research Letters,2004,31:L23311.
[4]宋海斌,董崇志,陈林,等.用反射地震方法研究物理海洋—地震海洋学简介[J].地球物理学进展,2008,23(4):1 156—1 164.
[5]葛勇.高分辨率地震资料处理技术在南海西部海区的应用[G]//海上地震资料高分辨率处理技术论文集.北京:地质出版社,2001,7:102—113.
[6]渥.伊尔马滋.地震数据处理[M].黄绪德,袁明德译.北京:石油工业出版社,1994.
[7]康艳芳,王凯,李红.以FOCUS系统为平台对塔里木盆地低信噪比地震资料处理方法探讨[J].新疆石油学院学报,2002,14(3):21-24.
[8]白硕,程志平.振幅补偿技术在地震资料处理中的发展及应用[J].能源与环境,2008,1:41—44.
[9]李继光.低信噪比地震资料处理技术研究[D].中国海洋大学硕士毕业论文,2003.
[10]吴培木,郭小钢,吴日升.台湾岛恒春西南海域声速场特性分析[J],海洋学报,2002,24(增刊1):179—190.
[2]HOLBROOK W S,PARAMO P,PEARSE S,et al.Thermo-haline Fine Structure in an Oceanographic Front from Seis-mic Reflection Profiling[J].Science,2003,301:821—824.
[3]NANDI P,HOLBROOK W S,PEARSE S,et al.Seismicreflection imagine of water mass boundaries in the Norwe-gian Sea[J].Geophysical Research Letters,2004,31:L23311.
[4]宋海斌,董崇志,陈林,等.用反射地震方法研究物理海洋—地震海洋学简介[J].地球物理学进展,2008,23(4):1 156—1 164.
[5]葛勇.高分辨率地震资料处理技术在南海西部海区的应用[G]//海上地震资料高分辨率处理技术论文集.北京:地质出版社,2001,7:102—113.
[6]渥.伊尔马滋.地震数据处理[M].黄绪德,袁明德译.北京:石油工业出版社,1994.
[7]康艳芳,王凯,李红.以FOCUS系统为平台对塔里木盆地低信噪比地震资料处理方法探讨[J].新疆石油学院学报,2002,14(3):21-24.
[8]白硕,程志平.振幅补偿技术在地震资料处理中的发展及应用[J].能源与环境,2008,1:41—44.
[9]李继光.低信噪比地震资料处理技术研究[D].中国海洋大学硕士毕业论文,2003.
[10]吴培木,郭小钢,吴日升.台湾岛恒春西南海域声速场特性分析[J],海洋学报,2002,24(增刊1):179—190.
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