地下き裂の相対座標を推定するための近接型AEダブレットの自動検出法

摘要

Automatic detection of proximity Acoustic Emission (AE) doublets is described in this paper. Proximity AE doublets are microseismic data in which the second event with a similar waveform arrives before attenuation of the first event. Number of AE events is much more than thousand when a subsurface fracture reservoir is stimulated during hydraulic fracturing. It is routine and huge work to detect proximity AE doublets in the many AE events. Cepstrum of proximity AE doublets has a peak at quefrency that shows interval between P-waves. We analyze three-component AE signal, which represents three-dimensional particle motion of AE. Three-component AE measurement is often carried out in subsurface AE measurement. Quefrency of the maximum of cepstrum is compared among three components. Cepstrums of proximity AE doublets have the maximum at similar quefrency in three components. On the other hands, cepstrums of AE events except for proximity AE doublets have the maximum at different quefrency in three components. 94 % of proximity AE doublets are detected automatically and 100 % of AE events that are not proximity AE doublets are not recognized as proximity AE doublets in the automatic detection.%地球温暖化問題に対して再生可能エネルギーの利用拡大rnは急務かつ重要な課題である。地熱エネルギーは，環境へrnの負荷が小さく，他の再生可能なエネルギー源に比べて高rnい出力を安定して供給できる利点をもつ。さらに，日本はrn火山国のため，欧米諸国に比べて地熱資源に恵まれているrn点でも，日本において地熱エネルギー開発を進める意義はrn大きい。