METHOD OF SEISMIC EXPLORATION FOR DIRECT OIL DEPOSIT FORECAST Russian patent published in 1998 - IPC

FIELD: geophysical exploration. SUBSTANCE: when exciting elastic vibrations of drill column in the borehole drilling process, vibrations at different distances of receiving points from borehole mouth are recorded and useful signals are selected by way of forming cross-correlation functions, wave fields are recorded within infralow-frequency range 1-10 Hz, and then oil-and-gas deposit- emitted characteristic quasi-harmonic vibrations of induced seismoacoustic emission initiated by action of drilling tool are recorded. Seismic records are submitted to spectral analysis and most intensive monochromic constituents of the component of induced seismoacoustic emission are determined and selected by means of monochromic correlation. Monocorrelograms of single consecutive actions within advancing length are accumulated: D < λ/4 where λ is wavelength of the component of induced seismoacoustic emission. Finally, from dynamics of change of amplitudes within time range corresponding to accumulation of infralow-frequency constituents of recorded wave field, one determines time of arrival of maximum values of amplitudes of abnormal signals 1.5-2-fold exceeding background values, from which one can forecast existence of oil-and-gas deposits. EFFECT: increased oil-and-gas deposit forecast accuracy.