Testing and Evaluation of a Single Well Seismic System Using a Clamped Downhole Vibrator and Clamped Geophones

72988B03-I Borehole seismology is the highest resolution, three-dimensional (3D) seismic imaging technique available to the natural gas industry for characterizing and monitoring natural gas reservoirs, and for optimizing the reservoir drilling programs. However, the industry¿s ability to economically conduct this imaging in deep and complex gas reservoirs is currently frustrated by the lack of the sophisticated acquisition technology to record the borehole seismic data (high frequency, high signal-to-noise-ratio, high fidelity) needed for high resolution 3D imaging. This project will integrate a field-proven, clamped downhole seismic vibrator with a field-proven, clamped downhole receiver array to form a single-well seismic system that can investigate the formation surrounding the well bore out to a radial distance of at least 3,000 ft. The unique broad bandwidth of the downhole seismic source (5 ¿ 1440 Hz) and its large force output (8,000 lbs) not only will provide high resolution capability but also will allow larger-volume formations to be investigated. Phase I will connect the downhole vibrator to the receiver array, and then the system will be clamped to the ground to simulate borehole deployment. All interface issues will be addressed and resolved in a controlled environment. Ultimately, a single-well seismic survey will be conducted so that a demonstration data set can be recorded and processed for the U.S. natural gas industry. Commercial Applications and Other Benefits as described by awardee: It is possible to record much higher frequency seismic data, with high signal-to-noise ratio, in boreholes than on the surface of the earth. A powerful clamped source and a clamped receiver array, in a single-well seismic system, should be able to record reflected and back scattered energy from fractures, faults, and formation boundaries at a large distance from the survey well. The high resolution images should allow for a much more cost effective drilling program for producing natural gas.