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应用振幅随炮检距变化(AVO)属性的剖面,如法向入射道(A)和梯度道(B)的乘积,在亮点AVO的分析和解释中已被广泛地使用。然而,尽管这些剖面对于具有低声波阻抗的亮点响应常有较好的效果,但对非亮点地震异常的识别则不可靠。当用普通的AVO属性剖面分析非亮点地震数据时:(1)不能识别砂岩和页岩盖层波阻抗差趋于零情况下的含气储层,或(2)当法向入射且梯度值的符号相反时,将获得不正确的AVO结果(负值)。我们将非亮点AVO炮检距响应分成两类:一类是有相位反转的情况,另一类则没有。本文通过两个例子给出了这两类AVO异常的分析方法。该方法主要是利用叠前响应的特性来获得一个更为明确的AVO属性剖面。且这项技术对上述两类非亮点AVO响应是合适的。通过与常规处理后的、对于波阻抗差极小的砂体以低振幅响应为特征的相对振幅地震剖面相比较,这项技术能识别出储层中含气孔隙流体的存在。
The application of amplitude profiles with offset AVO properties, such as the product of normal incidence (A) and gradient (B), has been widely used in the analysis and interpretation of the bright spot AVO. However, although these profiles are often good for bright-spot response with low acoustic impedance, recognition of non-bright-spot seismic anomalies is not reliable. When analyzing non-bright-point seismic data using a common AVO attribute profile: (1) gas-bearing reservoirs can not be identified where the wave impedance difference between sandstone and shale cap tends to be zero, or (2) when normal incidence and gradient values The opposite sign will result in an incorrect AVO result (negative value). We divide the non-bright AVO offset responses into two categories: one with phase reversal and the other without. In this paper, two examples of AVO anomaly analysis methods are given. The method mainly uses the characteristics of prestack response to get a clearer AVO profile. And this technology is suitable for the above two types of non-bright AVO response. This technique identifies the presence of pore-containing fluid in a reservoir by comparison with a conventionally treated relative amplitude seismic profile characterized by a low amplitude response for sand bodies with very small wave impedance differences.