基于S变换的低信噪比微震信息提取方法研究

Microseismic information extraction in low signal-to-noise ratio microseismic signal based on S-transform

低孔、低渗储层,特别是页岩气储层,已成为当前勘探开发的热点。压裂是这类储层的主要开发手段,而微震监测可对压裂过程和压裂效果进行直观评价。微震信号的检测与信息提取是微震监测的基础,在实际监测环境下,接收到的信号其信噪比较低,难以直接提取微震信息。因此,提出利用S变换对低信噪比微震数据进行时频分析的方法,并发现微震横波成分的抗噪能力较强。利用这一特征,对实际低信噪比微震监测数据进行处理,实现了对微震信号的有效提取。

Low porosity and permeability reservoirs, especially shale gas reservoirs, have been the focus of current oil and gas exploration and development. Fracturing is the main stimulation method for this kind of reservoirs. Moreover, micro- seismic monitoring is an effective tool of the fracturing processing monitoring and evaluation, and it is based on the micro- seismic detection and information extraction. However, it is difficult to record satisfied microseismic signal under complex geological conditions. This paper analyzed the characteristics of low signal-to-noise ratio microseismic signal using time- frequency analysis based S-transform. According to the time-frequency analysis of contaminated signals, S-wave component of microseismic events has a robust feature of anti-noise. Using the characteristics above, a satisfied result is achieved in the real microseismie monitoring processing with low signal-to-noise ratio.