振幅随偏移距变化(AVO)分析常常局限于反射面倾角和断层绕射波等多维传播效应可被忽略的情况。偏移—反演所提供的框架可扩大地震振幅在构造或地层效应重要区域的使用。在此过程中,使用未被破坏的叠前偏移把震源和接收器向下延拓进地层内。用正常偏移替代叠加资料,把叠前偏移资料用于AVO分析或其它反演技术中,以推断局部地下特性。叠前偏移可采取多种形式。实际上,共角度剖面的叠前时间偏移提供了一种常规方法,可用于改善AVO异常的横向分辨率和空间定位。在此方法中,首先按偏移方向进行平面波的分解,把波场分离为不同的传播角度,然后把资料集中为共角度剖面,每次偏移一个角度。共角度偏移具有一个简单形式,并被证明能适当地保持振幅随角度变化的特性。而后把正常AVO分析用于叠前偏移资料。墨西哥湾的地震测线实例说明了偏移是如何改善AVO分析的。实例的第一部分表明偏移改善了亮点处细微空间变化的成像质量。接着AVO分析展示了与干井位置有关的暗点,这些干井位置无法用传统处理技术来分辨,包括常规AVO和叠后偏移。实例的第二部分表明,利用偏移减少相干噪音和绕射的影响后,AVO响应得到改进。最后的实例说明了偏移对倾角AVO异常空间定位的影响。在所有实例中,偏移不仅提高了AVO异常的信噪比,而且改善了其? Amplitude with offset variation (AVO) analysis is often confined to cases where multidimensional propagation effects such as reflection angle dip and fault diffraction can be neglected. The framework provided by offset-inversion can expand the use of seismic amplitudes in important areas of tectonics or stratigraphic effects. In this process, the source and receiver are extended down into the formation using unspoiled prestack migration. Instead of superimposed data with normal offsets, prestack offset data is used in AVO analysis or other inversion techniques to infer local subsurface properties. Prestack migration can take many forms. In fact, the pre-stack time offset of the common-angle profile provides a common method that can be used to improve lateral resolution and spatial positioning of AVO anomalies. In this method, firstly, the plane wave is decomposed according to the direction of the offset, and the wave field is separated into different propagation angles. Then, the data is concentrated into a common angle profile, each of which is offset by an angle. The common angle offset has a simple form and has been shown to properly maintain the property that the amplitude varies with angle. Then use normal AVO analysis for prestack migration data. The example of the seismic survey in the Gulf of Mexico shows how offset improves AVO analysis. The first part of the example shows that the offset improves the imaging quality of the subtle spatial changes at the bright spot. The AVO analysis then shows the dark spots associated with dry well locations that can not be resolved using conventional processing techniques, including conventional AVO and post-stack migration. The second part of the example shows that the AVO response is improved by using offsets to reduce the effects of coherent noise and diffraction. The final example illustrates the effect of offset on the anomalous spatial orientation of dip AVO. In all cases, the offset not only improves the signal-to-noise ratio of AVO anomalies, but also improves it?