| 摘要 |
A method of using oriented seismic sensors to delineate the surface of a geologic unit having an anomalous velocity, such as salt dome is disclosed. Seismic sensors having three orthogonal axes of sensitivity are sealed in a housing and are attached to the outside of a tubing means. The tubing means is lowered into a wellbore that penetrates the geologic unit to a known depth, and a liquid such as cement is pumped through the tubing and up the annular space to fixedly attach the sensors to the geologic formation. The orientation of the sensor axes can then be calculated from an observed orientation of the reference directions of the sensor housings. Seismic wavefields are then propagated through the geologic unit and the surrounding earth, and are observed by the sensor axes of sensitivity, and are recorded and transmitted to the top of the tubing. In another embodiment, the orientation of the sensors is determined by fixedly attaching an object that emits particles in a field close to the sensor and positioning the sensor on the outside of a tubing means. The tubing means is lowered into a wellbore, and a tool is then lowered to sense and determine the direction of the radiation field and the inclination of the tubing means, to determine the orientation of the sensing device.
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