oa Seismic Repeatability - Is There a Limit?

The results of a 13-day seismic monitoring experiment are presented. It consists in 2 permanent<br>piezoelectric sources, one cemented in depth and the other attached to a surface concrete pad and 28<br>sensors, 14 at the surface and 14 cemented below the weathering zone.<br>To enhance the signal-to-noise ratio, continuous averaging of the individual SP records is performed<br>providing an average daily SP. 4D attributes are measured on these daily averages. The best<br>repeatability is obtained when both sources and sensors are buried with time and amplitude variations<br>of 6 μs and 0.5% respectively. This extremely high precision level is far above what can be expected<br>from the most accurate surface acquisition methods currently available.