METHOD FOR SEISMIC PROSPECTING HYDROCARBONS AND METHOD OF DETERMINING ATTITUDE OF PRODUCING FORMATIONS ON HYDROCARBONS AND SEISMIC STATION FOR REALISING SAID METHOD Russian patent published in 2011 - IPC G01V1/00 

FIELD: physics.

SUBSTANCE: in contrast to existing methods, the disclosed engineering solution further involves recording tsunami wave pressure at the bottom at frequencies 0.003-0.01 Hz using ocean-bottom seismographs with 0.003-20 Hz wideband seismic channels; the picked up signals are transmitted over a hydroacoustic communication channel to drift buoys placed on the investigated points, picked up signals from which are transmitted over a satellite communication channel to reference points, wherein magnetic field variation is additionally measured at frequencies 0.01-1.0 Hz, magnetic induction of the electromagnetic field is measured at frequencies 1-200 Hz, the electric component of the electromagnetic field is measured at frequencies 1-500 Hz, acoustic noise is measured at frequencies 5-50000 Hz, seismic noise is measures at frequencies 0.01-20 Hz, hydrodynamic noise of the sea is measured at frequencies 0.01-100 Hz in tectonic zones; factorial analysis is performed based on the measured parameters at the level of natural geophysical background and geophysical background during the period when the sun and the moon are on one celestial line, by plotting a curve of the amplitude of gradients of seismic, geodeforamation, geochemical and hydrophysical factors based on measurement which do not exceed 50-100 km in middle latitudes and 8-10 km in high and equatorial latitudes respectively, while aligning the measuring apparatus on eight bearings; additionally, seismic noise is measured at frequencies 0.008-20 Hz at the water-ground boundary, wherein odd harmonics 0.003 and 0.005 Hz are picked up from the spectrum of horizontal components, and even harmonics 0.002, 0.004, 0.006 and 0.008 Hz are picked up from the spectrum of the vertical component, and the coastal seismic stations measure the tidal level; measuring devices are placed at observation depth horizons which are multiples of 20 m, with maximum observation horizon equal to 100 m, uniformly distributed on the azimuth; hydroacoustic signals are detected with picking up of phase types PP, S and T; the arrival of an acoustic wave of seismic origins is determined from the frequency shift value of the scattered radiation, wherein the recording devices placed away from the coastal zone perform analysis of low-frequency components of the scattered signal using ship navigation noise as reference quasi-harmonic high-frequency signals, and recording devices placed in the coastal zone determine the onset and direction of arrival of seismic waves via narrow-band filtration and spectral analysis of waves, phase types PP, S and T are picked up via narrow-band filtration using recursive Butterworth filters. Input filtration is carried out using recursive filters with integral coefficients, and signals with sampling frequency of 100 Hz or less are filtered with floating point number coefficients; hydroacoustic signals are picked up using wideband ocean-bottom seismographs with not less than three seismic channels. Signals are analysed using three independent detectors, and the detection signal is generated upon coincidence of signals from at least two of three channels; spectral analysis is performed for volume waves with phases PP and S, and for Love, Rayleigh and Stonely surface waves; plotting the map of amplitude variations of the microseismic signal for each spectral frequency of spatial variations, as well as associating each obtained map with its corresponding depth is carried out by approximating the profile of the vertical relief relative the coastal line. The basic spline used is a cubic spline with zero boundary derivatives, wherein construction of a two-dimensional spline-function is executed through tensor product of one-dimensional splines. The measurement base at the sea floor is formed by placing seismic receivers at a distance of not more than 5 km from each other to form an isosceles triangle in the underwater space, at the vertices of which seismic receivers are placed. Hydroacoustic antennae of the seismic receivers include four transceivers of acoustic signals mounted on a perforated arm with formation of two single-channel and one double-channel transceivers, the antennae of single-channel transceivers lying 1000 mm from each other in the frontal zones of the perforated arm. The double-channel transceiver is formed from two transceivers lying 50 mm from each other, one of which lies 200 mm from the first single-channel transceiver, and the second single-channel transceiver lies 800 mm from the second single-channel transceiver. The transceivers are arranged on the perforated arm to form two measurement bases having a common centre. Seismic vibration receivers are placed in the shelf zone, along the line of the foot of the continental slope and along the axis perpendicular to the Gardiner line on fault boundaries. The device additionally includes a methane sensor connected by its output to a recording and control unit, a coordinate-determining circuit connected by its input-output to the input-output of the recording and control unit, a block of wideband transducers in which wideband transducers are in form of a sealed cylindrical vessel divided by a partition wall into compartments filled with an electrically conducting liquid. The partition wall has a hole in the middle and on whose sides there are mesh electrodes. The butt-ends of the cylinder are in form of elastic membranes. The block of wideband transducers is connected by its input-output to the input-output of the recording and control unit. The block of highly sensitive seismic sensors comprises four transceivers of acoustic signals mounted on a perforated arm with formation of two single-channel and one double-channel transceivers, the antennae of single-channel transceivers lying 1000 mm from each other in the frontal zones of the perforated arm. The double-channel transceiver is formed from two transceivers lying 50 mm from each other, one of which lies 200 mm from the first single-channel transceiver, and the second single-channel transceiver lies 800 mm from the second single-channel transceiver. The transceivers are arranged on the perforated arm to form two measurement bases having a common centre. The housing of the mobile multichannel seismometric system is made from high-strength aluminium alloy with a protective coating in form of anodic oxidation with a multilayer paint coat.

EFFECT: fewer erroneously drilled wells, possibility of monitoring exploitation of production wells and gas storages during oil and gas extraction.

3 cl, 3 dwg