PROCESS OF HIGH-RESOLUTION SEISMIC PROSPECTING BY METHOD OF COMMON-DEPTH POINT WITH BLASTING OF CHARGES

摘要

FIELD: geophysics, seismic prospecting for mineral resources. SUBSTANCE: condition for occurrence of rocks in zone and beneath zone of small velocities are determined over investigated area by available geological/geophysical data prior to start of profile observations. Then minimal mass of charge and depth of its sinking below zone of small velocities providing for formation of information seismic signal with minimally possible length of valid wave and with intensity sufficient for isolation of valid waves against background of irregular waves-noises are determined at stage of preliminary seismic prospecting operations. Key seismic prospecting operations are conducted under chosen excitation parameters. In this case maximum distance xmax of "blast-instrument " is chosen at stage of key seismic prospecting operations from relationship , where Z is depth to desired reflecting horizon; N = fhzp/fmfp is coefficient of increase of predominant frequency of information seismic signal; fhzp is predominant frequency during high-resolution seismic prospecting; fmfp is predominant frequency during medium frequency seismic prospecting. Distance between centers of groups of geophones that should not exceed wave Nyquist number is chosen from relation , where ξ is wave Nyquist number; lambdamin is minimal length of wave of information seismic signal; Δx is distance between centers of groups of geophones. Seismic signal is recorded at seismic stations with quantization step Δt chosen from relation , where fmax is maximal width of spectrum of valid wave. EFFECT: improved reliability of process. 4 clo