Application of cepstral methods in restoring the mechanical characteristics of the upper geological section of formations

Abstract

The determination of geological structure characteristics has long been a well-known and persistent issue. Currently, there are numerous unsolved and pressing problems in this area, particularly regarding the method for determining the mechanical or velocity parameters of the upper geological section of formations. One method that enables exploration of the velocity and mechanical characteristics of the geological environment is microseismic monitoring. Various industrial fields require improved knowledge of the mechanical parameters in the upper portion of the environment. This paper focuses on solving the inverse problem of restoring the mechanical characteristics of the upper geological section of formations in a one-dimensional scenario. The input data consists of seismic signals, which represent surface fluctuations over time. The approach considered for solving the problem involves analyzing the cepstrum, which is the second Fourier series transformation obtained from the amplitude component of the spectrum derived from the original signal. By appropriately selecting the Fourier transform windows, the peaks in the cepstrum provide information about changes in the velocity characteristics of the upper section. The paper demonstrates the application of the proposed technique on synthetic data obtained using a one-dimensional solution and compares the reconstructed high-speed environment with the actual one. The upper portion of the layer section also remains poorly understood to date. This is mainly attributed to the limited interest of the oil and gas industry in the upper section, as it is relatively easy to drill through and has low mineral availability. The lack of knowledge about the upper section is also due, in part, to the ineffectiveness of traditional approaches (such as seismic and vertical seismic profiling) at these depths. The authors of this article showcase the potential use of the technique in environments with attenuation, thereby making it more suitable for studying real environments.