Least-squares reverse-time migration with a wavefield-separation imaging condition and updated source wavefields
Least-squares reverse-time migration with a wavefield-separation imaging condition and updated source wavefields
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DOI：
10.1190/geo2014-0020.1
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发表时间：
2014-08
期刊：
影响因子：
3.3
通讯作者：
Sirui Tan;Lianjie Huang
中科院分区：
文献类型：
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作者：
Sirui Tan;Lianjie Huang
摘要陡倾断裂带的直接成像是包括逆时偏移（RTM）在内的常规偏移的难点。提出了一种新的最小二乘RTM （LSRTM）方法来直接成像陡倾断裂带。该方法采用波场分离成像条件，并在每次迭代中更新源波场。我们的新成像方法产生的水平图像显示大部分陡倾断裂带。传统的最小二乘RTM不更新源波场，不能直接成像垂直断裂带。数值计算表明，在陡倾断裂带成像中，源波场的更新是至关重要的。利用合成地震资料，证明了LSRTM方法可以直接成像倾角达90°的陡倾断裂带。与传统的LSRTM方法相比，LSRTM方法对初始偏移速度模型的平滑性和速度误差的敏感性较低。
ABSTRACTDirectly imaging steeply dipping fault zones is difficult for conventional migration, including reverse-time migration (RTM). We developed a new least-squares RTM (LSRTM) method to directly image steeply dipping fault zones. The method uses a wavefield-separation imaging condition and updated source wavefields during each iteration. Our new imaging method produces horizontal-looking images that show mostly steeply dipping fault zones. Conventional least-squares RTM does not update source wavefields and cannot directly image vertical fault zones. We numerically determined that it is crucial to update source wavefields to image steeply dipping fault zones. Using synthetic seismic data, we proved that our new LSRTM method can directly image steeply dipping fault zones with dipping angles up to 90°. Compared with conventional LSRTM, our LSRTM method was less sensitive to the smoothness and the velocity error of the initial migration velocity model.