海上三维地震勘探的多方位角处理
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摘要
目标测区虽然在不同时期以不同的目的完成了两次常规的两个采集方向近乎正交的三维地震勘探,但是由于地下地质条件异常复杂,诸如浅层碳酸岩、盐丘刺穿、储层的反射系数较低、多次波发育等等,所以引入非传统海上三维地震资料处理方法——多方位角地震数据处理,对两块三维勘探数据,执行了面元网格归一、地震数据匹配以及建立斜方晶体各向异性速度模型。基于同先导试验叠加道进行互相关处理,利用多方位角叠加处理模块计算加权叠加值。多方位角处理数据较好地丰富了处理频率成分和频带宽度,改善了地震资料信噪比和地质成像效果,优化了断层成像。同时,基于工作实践指出进一步强化在地堑下方的低反射系数层的成像问题,仍然是未来地震处理技术的难题。
Two different conventional 3D offshore seismic surveys have been carried out at different time over the interested potential plays with difficult geological purposes.But it is very difficult for well data to map on seismic data,just under the conditions of complicated geology such as shallow carbonates,some zones of cementation,incised valleys,graben where there are salt diapirs and the low reflectivity reservoir and so on.Therefore,as a nonconventional processing method,multi-Azimuth(MAZ) 3D seismic data processing was introduced.Following performance of data regularization,matching and depth velocity model building of orthorhombic anisotropy,the module MAZ stack was used to compute weighted stacks based on cross-correlation with pilot stack.MAZ processing data result in wider frequency range,higher ratio of S/N and better imaging especially for faults.However,it is expected to further enhance the imaging quality in the area with low reflectivity beneath the graben.
Two different conventional 3D offshore seismic surveys have been carried out at different time over the interested potential plays with difficult geological purposes.But it is very difficult for well data to map on seismic data,just under the conditions of complicated geology such as shallow carbonates,some zones of cementation,incised valleys,graben where there are salt diapirs and the low reflectivity reservoir and so on.Therefore,as a nonconventional processing method,multi-Azimuth(MAZ) 3D seismic data processing was introduced.Following performance of data regularization,matching and depth velocity model building of orthorhombic anisotropy,the module MAZ stack was used to compute weighted stacks based on cross-correlation with pilot stack.MAZ processing data result in wider frequency range,higher ratio of S/N and better imaging especially for faults.However,it is expected to further enhance the imaging quality in the area with low reflectivity beneath the graben.
引文
[1]Keggin J,Manning T,Rietveld W,et al.Key aspects of Multi-Azimuth acquisition and processing[C].SEG Annual Meeting, New Orleans,Louisiana,2006.
[2]Manning T,Keggin J,Rietveld W E A,et al.Multi-azimuth(MAZ) towed streamer data processing flow from the Nile Delta[C].SEG Annual Meeting,New Orleans,Louisiana,2006.
[3]Birdus S,Sun J,Sun W,et al.Multi-Azimuth PSDM Processing in the Presence of Orthorhombic Anisotropy ~ Case History Offshore North West Australia[C].SEG Annual Meeting,Las Vegas,2012.
[2]Manning T,Keggin J,Rietveld W E A,et al.Multi-azimuth(MAZ) towed streamer data processing flow from the Nile Delta[C].SEG Annual Meeting,New Orleans,Louisiana,2006.
[3]Birdus S,Sun J,Sun W,et al.Multi-Azimuth PSDM Processing in the Presence of Orthorhombic Anisotropy ~ Case History Offshore North West Australia[C].SEG Annual Meeting,Las Vegas,2012.
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