OBS记录的时间和定位误差校正
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摘要
根据地震波传播的时距关系,利用海底地震仪子母钟对时记录、测深数据和近炮点数据,使用数据处理软件OBSTOOL,对南海北部采集的海底地震记录进行高精度时钟校正处理。通过反演确定放炮延迟和海底地震仪的漂移参数,为准确反演速度奠定了基础。分析结果显示,南海北部OBS数据放炮延迟为1.278s,最大时钟校正量为2.394 s,OBS偏离测线最大距离为652m,这些将会导致浅层正、反演结果不准确,影响BSR的正确识别。
Based on the time-distance equation and by the OBSTOOL software,high-precision clock correction for ocean bottom seismograph(OBS)data from the northern South China Sea is processed using clock file,depth recorder and nearoffset OBS data.Exact shot delay and drift values are determined by the inversion,establishing the base of accurate velocity inversion.The analysis result showed that the shot delay is 1.278s,the largest clock correction is 2.394s,and the largest deviation from the profile is about 652m,which may cause the inaccuracy of forwarding and inversion for the velocity structure in shallow layers and affect the identification of bottom simulating reflection(BSR).
Based on the time-distance equation and by the OBSTOOL software,high-precision clock correction for ocean bottom seismograph(OBS)data from the northern South China Sea is processed using clock file,depth recorder and nearoffset OBS data.Exact shot delay and drift values are determined by the inversion,establishing the base of accurate velocity inversion.The analysis result showed that the shot delay is 1.278s,the largest clock correction is 2.394s,and the largest deviation from the profile is about 652m,which may cause the inaccuracy of forwarding and inversion for the velocity structure in shallow layers and affect the identification of bottom simulating reflection(BSR).
引文
[1]阎贫,刘昭蜀,姜绍仁.南海北部地壳的深地震地质结构探测[J].海洋地质与第四纪地质,1997,17(2):21—27.
[2]PHILIPPE S,LIU C S,HSIUAN T H,et al.Characteris-tics of gas hydrate and free gas offshore southwestern Tai-wan from a combined MCS/OBS data analysis[J].Mar Geo-phys Res,2004,25(1—2):157—180.
[3]丘学林,赵明辉,叶春明,等.南海东北部海陆联测与海底地震仪探测[J].大地构造与成矿学,2003,27(4):295—300.
[4]YOSIO N,PAUL L D,PHILLIP H R,et al.Large-offsetseismic surveying using ocean-bottom seismographs and airguns:Instrumentation and field technique[J].Geophysics,1987,52:1 601—1 611.
[5]CHRISTESON G.OBSTOOL:Software for ProcessingUTIG OBS Data[M].University of Texas Institute for Ge-ophysics,1998:11.
[6]SLOAN E D.Clatherates Hydrates of Natural Gases[M].New York:Marcel Decker Inc,1998:1—641.
[7]PHILIPPE S,HSIUAN T H,LIU C S.Constraints on freegas and gas hydrate bearing sediments from multi-channelseismic data,offshore southwestern Taiwan[J].PetroleumGeology of Taiwan,1999,33(16):21—42.
[8]MILLER J J,LEE M W,von HUENE R.An analysis of aseismic reflection from the base of a gas hydrate zone,off-shore Peru[J].AAPGB,1991,75:910—924.
[9]HYNDMAN R D,DAVIS E E.A mechanism for formationof methane hydrate and seafloor bottom simulating reflectorsby vertical fluid expulsion[J].J G R,1992,97:7 025—7 041.
[10]BANGS L N B,SAWYER C S,GOLOVCHENKO T.Freegas at the base of the gas hydrate zone in the vicinity of theChile triple junction[J].Geology,1993,21:905—908.
[2]PHILIPPE S,LIU C S,HSIUAN T H,et al.Characteris-tics of gas hydrate and free gas offshore southwestern Tai-wan from a combined MCS/OBS data analysis[J].Mar Geo-phys Res,2004,25(1—2):157—180.
[3]丘学林,赵明辉,叶春明,等.南海东北部海陆联测与海底地震仪探测[J].大地构造与成矿学,2003,27(4):295—300.
[4]YOSIO N,PAUL L D,PHILLIP H R,et al.Large-offsetseismic surveying using ocean-bottom seismographs and airguns:Instrumentation and field technique[J].Geophysics,1987,52:1 601—1 611.
[5]CHRISTESON G.OBSTOOL:Software for ProcessingUTIG OBS Data[M].University of Texas Institute for Ge-ophysics,1998:11.
[6]SLOAN E D.Clatherates Hydrates of Natural Gases[M].New York:Marcel Decker Inc,1998:1—641.
[7]PHILIPPE S,HSIUAN T H,LIU C S.Constraints on freegas and gas hydrate bearing sediments from multi-channelseismic data,offshore southwestern Taiwan[J].PetroleumGeology of Taiwan,1999,33(16):21—42.
[8]MILLER J J,LEE M W,von HUENE R.An analysis of aseismic reflection from the base of a gas hydrate zone,off-shore Peru[J].AAPGB,1991,75:910—924.
[9]HYNDMAN R D,DAVIS E E.A mechanism for formationof methane hydrate and seafloor bottom simulating reflectorsby vertical fluid expulsion[J].J G R,1992,97:7 025—7 041.
[10]BANGS L N B,SAWYER C S,GOLOVCHENKO T.Freegas at the base of the gas hydrate zone in the vicinity of theChile triple junction[J].Geology,1993,21:905—908.
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