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AVO截距和梯度及其交会图是岩性变化识别和油气异常检测的有效手段.但从纵波地震资料中提取的梯度值精确度不高,这是由于梯度属性中含有横波速度和密度成份.为此,本文提出联合使用纵波和转换横波来提取截距和梯度属性方法.首先,本文基于Aki-Richards建立的转换横波反射系数近似式,将上下层纵波速度、横波速度、密度参数进行等量代换推导出以AVO截距和梯度为参数的转换横波反射系数近似式.然后,基于多波多分量地震资料实现了纵波和转换横波联合提取AVO截距和梯度属性参数.层状模型测试表明联合使用纵波和转换横波比仅用纵波提取的AVO梯度参数精度高,并且对背景噪声有一定的压制而获得更稳定的梯度属性结果.多分量实际资料提取的截距属性可指示目标层的流体信息,而通过截距和梯度差属性显示目标层的流体呈局部富集,更符合测试工区的流体分布状况.
AVO intercepts and gradients and their cross plots are effective methods for lithologic identification and hydrocarbon anomaly detection, but the accuracy of gradient values extracted from P-wave seismic data is not high due to the inclusion of shear-wave velocity and density components in the gradient properties. Therefore, this paper proposes a method to extract the intercept and gradient using the combination of P-wave and S-wave transformation.Firstly, based on the approximate formula of converted S-wave reflection coefficient established by Aki-Richards, the parameters of P wave velocity, S wave velocity, Substitutions derive an approximation of the transversal shear-wave reflection coefficient with the intercept and gradient of AVO.And then, based on the multi-wave and multi-component seismic data, the compressional shear wave and the transversal shear wave are combined to extract the intercept and gradient attribute parameters of AVO.The stratified model test shows that the joint Using the P-wave and transform-shear waves is more accurate than the AVO-gradient parameters extracted using only longitudinal waves, and the background noise is suppressed to obtain more stable gradient property results.The multi-component actual data extraction intercept attribute can indicate the target layer’s fluid information , While the fluid in the target layer shows partial enrichment by the intercept and gradient difference properties, which is more in line with the test work area Distribution.