Calibration and Testing of Sonic Stimulation Technologies

In conjunction with Baker Atlas Inc. Michigan Technological University devised a system capable of recording the earth motion and pressure due to downhole and surface seismic sources. The essential elements of the system are 1) a borehole test site that will remain constant and is available all the time and for any length of time, 2) a downhole sonde that will itself remain constant and, because of its downhole digitization feature, does not require the wireline or surface recording components to remain constant, and 3) a set of procedures that ensures that the amplitude and frequency parameters of a wide range of sources can be compared with confidence. This system was used to record four seismic sources, three downhole sources and one surface source. A single activation of each of the downhole sources was not seen on time traces above the ambient noise, however, one sweep of the surface source, a small vertical vibrator, was easily seen in a time trace. One of the downhole sources was seen by means of a spike in its spectrum and a second downhole source was clearly seen after correlation and stacking. The surface vibrator produced a peak to peak particle motion signal of approximately 4.5 X 10-5 cm/sec and a peak to peak pressure of approx. 2.5 X 10-7 microPascals at a depth of 1,485 ft. Theoretical advances were made with our partner, Dr. I. Beresnev at Iowa State University. A theory has been developed to account for the behavior of oil ganglia trapped in pore throats, and their ultimate release through the additional incremental pressure associated with sonic stimulation