Experimental study of an advanced three-component borehole seismic receiver

An advanced three-component borehole seismic receiver has been designed, developed, and tested. This receiver was designed with the aid of finite element vibration modeling to be free of significant clamp resonances below 2000 Hz. This broad frequency range makes this sonde well suited for cross-well seismic imaging applications. State-of-the art piezoelectric accelerometers are used as the three-component sensors and provide signal enhancement relative to conventional geophones. The use of these accelerometers offer a signal-to-noise enhancement of approximately 20 dB at 1000 Hz over moving-coil seismic geophones. Additional features of the sonde include high temperature/pressure operation, small size, lightweight, field-durable construction, and multi-station expansion capability. A prototype accelerometer-based sonde was field tested at the Texaco Humble Field to determine its performance characteristics. A borehole explosive source was used to test the sonde in a cross-well configuration (815 ft well-to-well separation). For comparison purposes, similar cross-well tests were performed using a commercial VSP-type tool and buried/cemented geophones. The advanced sonde exhibited significantly improved coupling relative to the VSP tool as evidenced by increased bandwidth and signal-to-noise ratio. Accordingly, the advanced sonde produced signals which rival those produced by the buried/cemented geophones. 5 refs., 6 figs.