改进的地震相干体算法及其应用——以乌克兰顿涅茨盆地裂缝型储层为例

Improvements of seismic coherence measure and an integrated use of this attribute for studying fracture reservoirs in the Donets Basin, Ukraine

地震相干体是一种地震属性,旨在刻画由构造、地层、岩性、孔隙及油气的变化所引起的图像不连续性。对该属性的计算与应用技术进行了改进,并通过分析其与假定地震资料数学模型之间的关系,提出了一种估算地震相干体的新方法。该方法基于一种更符合实际情况的数据模型,允许参与相干体计算的地震道之间的信号振幅与噪声方差任意变化。此外,提出了一种提高相干体算法横向分辨能力的广义方法。利用地震合成数据对这些方法进行了测试。结合地震曲率属性,利用新的相干体算法对乌克兰顿涅茨盆地煤层气裂缝型储层进行了研究。

Seismic coherence is a popular attribute intended to image discontinuities caused by variations in structure, stratigraphy, lithology, porosity, and the presence of hydrocarbons. We improve the technology of computing and utilizing this attribute. After analyzing the relation of this attribute to the supposed mathematical model of seismic data, we present a new method for estimating coherence. It is based on a more realistic data model that permits arbitrary variations of both signal amplitudes and noise variances between the traces participating in coherence calculation. Moreover, a generalized approach to enhance the horizontal resolving power of any coherence measure is suggested. The new methods are tested on synthetic data. Moreover, in combination with another seismic attribute, curvature, the new coherence measure is used for studying coalbed-methane-bearing fracture reservoirs in the Donets Basin of Ukraine.