SEISMIC SURVEY METHOD FOR DETERMINING POSITION OF LOW-SPEED AND HIGH-SPEED GEOLOGICAL BODIES ALONG DEEP SECTION IN AREAS COMPLICATED BY RELIEF Russian patent published in 2025 - IPC G01V1/28 G01V1/30 

FIELD: measuring.

SUBSTANCE: invention relates to seismic exploration and can be used to search for deposits, in particular ore, diamond and hydrocarbon deposits, to determine consolidated zones and zones of low strength in areas complicated by relief other than flat. According to the disclosed solution, at least two vertical seismometers with identical amplitude-frequency characteristics are installed on the investigated profile X of length L_X, one of which Z₀ is fixed, and the rest – with possibility of movement and installation in each measurement point j with coordinate x_j with pitch Δx, not exceeding minimum depth of investigation H_min. Microseismic signals consisting of Rayleigh waves are synchronously recorded by seismometers Z₀ and Z_j at each point j during recording time intervals T_j, duration of which is determined by period of stationarity of microseismic signal. Calculating power spectra of microseismic signal S_j(f_k) of seismometers Z_j in each measurement point j, where f_k is frequency in spectrum, and power spectra S_0,j(f_k) of signals of stationary seismometer Z₀ for each recording time interval T_j. Then the relative power spectrum is calculated w(x_j, f_k) at each measurement point j with coordinate x_j and for each selected frequency f_k by finding ratios of obtained power spectra S_j(f_k) and corresponding to them on time interval T_j power spectra S_0,j(f_k) according to the formula w(x_j, f_k) = S_j(f_k)/S_0,j(f_k). Then, relative power spectrum w(x_j, f_k) averaged over all points j is calculated according to the formula w₀(f_k)=1/n∑_jw(x_j, f_k), where n is the number of points j of recording the microseismic signal by seismometers Z_j and the deviation of power spectra from the average relative power spectrum according to the formula W(x_j, f_k)=w(x_j, f_k)-w₀(f_k). Determining wavelengths λ_k of the Rayleigh surface wave for each selected frequency f_k in the spectrum. From all points i for each point j and for each wavelength λ_k sets Ω_j,k of points i are selected, the coordinates of which fall into the segment of the profile defined by the condition x_j-L_k/2≤x_i≤x_j+L_k/2, where L_k is the length of the averaging segment of the relief level, determined from the relationship L_k=k_L×λ_k, where k_L is a numerical coefficient estimated from numerical simulation and equal to k_L≈2-4, λ_k is Rayleigh wavelength, f_k is frequency in spectrum. Calculated at each point j and for each wavelength λ_k of the middle elevation of the relief level H₀(λ_k, _xj) as average weighted value Hi with weight mi for all points i from set Ω_j,k, where weight m_i of value H_i for extreme points i is equal to m_i=2⋅r₂⋅Δx, and for all other points i is determined by formula m_i=(x_i+1-x_i-1)/2. Deep section W(x_j, H_k) is constructed along profile X by linking the calculated deviation values of relative power spectra W(x_j, f_k) to points in space under each measurement point j with coordinate x_j and depth position H_k according to ratio H_k=H₀(λ_k, x_j)-k_G×λ_k, where k_G is an experimentally established numerical coefficient depending on rock components. Positions x along the profile and depth H of low-speed geological bodies on the deep section are determined by selecting areas with high positive value of W(x, H) and high-speed geological bodies on areas with low negative value of W(x, H) on the deep section.

EFFECT: high information content and reliability of the obtained data.

1 cl, 1 dwg