Reverse time migration of multiples for subsalt imaging
Reverse time migration of multiples for subsalt imaging
复制标题
盐下成像多次波逆时偏移
DOI：
10.1190/geo2010-0312.1
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发表时间：
2011-09-01
期刊：
影响因子：
3.3
通讯作者：
Zheng, Yingcai
中科院分区：
文献类型：
--
作者：
Liu, Yike;Chang, Xu;Zheng, Yingcai
一些油气藏被困在盐体下，由于光照不足，地震成像受到很大挑战。多次反射与主反射具有不同的传播波路径，因此可以用于补充无法获得盐下主反射的照明。因此，与仅使用一次反射的常规偏移相比，多次偏移有时可以提供更好的盐下图像。Inthispaper, weproposetomodifyconventionalreversetimemigrationsothatmultiplescanbeused asconstructivereflectionenergyforsubsaltimaging。该方法将脉冲源小波替换为包含一次和多次的记录数据，并使用预测的多次作为输入数据，而不是一次反射。在逆时偏移过程中，将地面记录的多次波在时间上向后外推到每个深度水平，将原初和多次波的观测数据在时间上向前外推到相同的深度水平，然后进行相互相关成像条件。在Sigsbee2B数据集上的数值试验表明，与传统的一次反射偏移相比，多次反射偏移可以实现更大的覆盖范围和更均衡的地下光照。这个例子表明，反向时间偏移倍数可能是复杂盐下成像的一种有前途的方法。
Some hydrocarbon reservoirs are trapped beneath salt bodies, where seismic imaging is greatly challenged due to poor illumination. Multiple reflections have different propagation wave paths from primary reflections and thus can be used to complement the illuminations where primary reflections from beneath the salt are not acquired. Consequently, migration of multiples can sometimes provide better subsalt images compared to conventional migration which uses primaryreflectionsonly.Inthispaper,weproposetomodifyconventionalreversetimemigrationsothatmultiplescanbeused asconstructivereflectionenergyforsubsaltimaging.Thisnew approach replaces the impulsive source wavelet with the recorded data containing both primaries and multiples and uses predicted multiples as the input data instead of primary reflections. In the reverse time migration process, multiples recorded on the surface are extrapolated backward in time toeachdepthlevel,andtheobserveddatawithbothprimaries and multiples are extrapolated forward in time to the same depth levels, followed by a crosscorrelation imaging condition. A numerical test on the Sigsbee2B data set shows that awidercoverageandamorebalancedilluminationofthesubsurface can be achieved by migration of multiples compared with conventional migration of primary reflections. This exampledemonstratesthatreversetimemigrationofmultiples might be a promising method for complex subsalt imaging.