SU680455A1 - System for seismic observations - Google Patents

Description

about "680455

Union of Soviet Socialist

Republics

USSR State Committee

Inventions

TO AUTHOR'S CERTIFICATE (61) Additional to author. certificate · - (22) Announced on 08.08.77 (21) 2523679 / 18-25 with application joining - (23) Priority - (5!) MKi ³ G 01 V 1/16 for inventions and discoveries (43) Published 11/07/80. Bulletin X ° 41 (45) Date of publication of the description 04.01.81 (53) UDC 550.83 (088.8)

(72) Authors inventions V. Ya. Bendersky and M.I. Chervonsky (71) Applicant Ukrainian Research Geological Exploration Institute

(54) SEISMIC OBSERVATION SYSTEM

2

The invention relates to the field of seismic exploration and can be used in direct searches of oil and gas deposits using seismic exploration.

It is known that the main reflections in the form of pulses clearly determined by the amplitude of the pulses corresponding to sharp and extended interfaces of the formation are recorded on the seismograms of the MOU in the field of oil and gas contacts; implicitly 10 expressed and interfering with the main reflected and diffracted. waves associated with unstretched and unsharp interfaces existing in the oil-vada (VNK) contact region, ¹⁵ gas-water (VGK), gas-oil (OGC).

A known observation system for fan seismic sounding, with the help of which determine the optimal direction of seismic profiles, the nature of the waves coming in 20 not in a vertical plane, the elements of occurrence of reflecting sites [1] · However, the use of such installations does not solve the problem of predicting OGCs , VNK and VGK, since at 25 of their application it is impossible to implement interference systems that allow one to distinguish weak reflected waves coming from these contacts.

A system for seismic observations is also known, in which, in order to register the spatial wave field reflected from the seismic boundaries, the seismic receivers 5 are arranged on a square grid or along the rays located from the point of explosion [2].

However, when using such a system, as well as when using traditional systems for seismic exploration, it is impossible to improve the quality of reflections from VNK, VGK and OGK, since the system is sensitive to lateral reflections.

The purpose of the invention is to increase the sensitivity of the system to waves reflected from horizontal boundaries and, in particular, water-oil and gas contacts.

This goal is achieved by the fact that the geophones (groups of seismic receivers) are located on concentric circles centered at the point of excitation of seismic vibrations, the outputs of the geophones (groups of geophones) located on each circle are connected in a single group, the output of which is connected to the input of one of the recording channels.

The system is implemented as follows. Separate seismic receivers or groups of seismic receivers are arranged in concentric circles, the center of which coincides with the point of excitation of seismic waves, connect a set of seismic receivers or outputs of sets of groups of seismic receivers equidistant from the point of excitation, into a single secondary group of seismic receivers in their recording channel.

The drawing shows the central installation of geophones, connected to the secondary groups equidistant from the point of explosion, and its flank version.

The drawing shows the excitation point 1, individual geophones 2 or groups of seismic receivers, the connection of individual geophones 1H1iks 3 or their groups to secondary points, channel outputs of 4 secondary-groups of geophones to the recording equipment, I – I profile line.

The system operates as follows.

When seismic waves are excited, the signals of the reflection fronts from the oil-gas contact will approach each secondary group of geophones, i.e., all geophones equally included in the secondary group from the point of explosion simultaneously. Therefore, at the output of each separate secondary group of geophones, the recorded total oscillation will be characterized by increased amplitude.

On the obtained seismogram, the in-phase axes of the total wave reflections from the OWC, OGC or OGC or from the boundaries having horizontal (or close to horizontal) occurrence are fixed.

At the same time, waves reflected from inclined boundaries confined to sedimentary formations are summed non-phase and will be suppressed. Moreover, each trace of the total record is conditionally tied to the points of intersection of concentric circles with the profile.

To obtain the next record (seismogram), the explosion point with all the secondary groups of seismic receivers is rearranged at a distance at which the arrangement of neighboring secondary groups overlap, which allows you to create a system of hodographs linked by reciprocal points constructed along the common-axis axes of the total signals, including and multiple overlap system.

When the profile crosses the boundary of the reservoir, waves from the object under study are not traced, and thus, after appropriate processing, the boundary of the water-oil and gas contact is established by the disappearance of the axis-phase waves of the waves with an infinite apparent speed.

The processing method of the obtained seismograms is as follows.

Repeated summation of the signals recorded on the seismograms after entering the kinematic corrections is obtained in this way the value of / ₀ from the studied water-oil and gas contact along the profile with simultaneous suppression of multiple waves. When working out in the field network profiles in this way receive as a result of subsequent processing a card t ₀ . Performing an analysis of velocities over the area, a velocity map is constructed to the contact under investigation. Finally, a structural map of the water-oil and gas contact is constructed using the map t ₀ and the velocity map.

The advantage of this system over the well-known is that it implements the possibility of direct determination and contouring of oil-and-gas-promising deposits, regardless of the type of structure with an arbitrary arrangement of profiles relative to the elements of the strike of the reservoir according to seismic data.

The system has significant noise immunity and makes it possible to double-use-useful signals - weak reflections from oil and gas contacts. The first summation is carried out in the field, when recording seismic reflected waves, the second - in the process of processing the received data. This circumstance makes it possible to more reliably determine the presence of a water-oil and gas contact.

Implementation of the proposed method will reduce the number of deep wells, with the help of which the reservoir is investigated, which will give a significant economic effect.

Claims (2)

(54) SYSTEM FOR SEISMIC OBSERVATIONS coincides with the point of excitation of seismic waters, connect a set of signal reception or “Exits 1sovo: buy a group of seyomopriemini | COV; equidistant from the excitation line, one unit from the excitation unit; seismic group 1MN1I1SHV to its channel zalnoi. The drawing shows the central installation of seismic receivers connected in the iBTOpH4iKbie group (equidistant from the explosion point and its flanking variant. In the drawing there are 1 point / excitation, separate seismic ground signals, 1 or 2, or groups of seymoprotectors, connection of seismic ascents, etc.). secondary points, channel-by-outputs of 4 secondary groups of seismic detectors to recording equipment, II LINE OF ARROWS n. The system works in the following way.With excitation of Cumulative waves, signals of reflection fronts from B1odon the fuzz contact will approach each secondary group of receiver receivers, i.e., all the receivers equidistant from the point of explosion that belong to the secondary group at the same time. Therefore, the output of a separate secondary group of seismic receivers recorded by iCyMMapapoe will have a higher amplitude range. of the creeping seismogram, the axes of the phase reflection of the total reflections of the waves from the military-industrial complex, VGK or NGK 1ilo from the boundaries having horizontal (or close to horizontal) occurrence are fixed. At the same time, the waves reflected from the sloping boundaries confined to the sedimentary patterns, vanities: m, are summed up, Nesynfaeno, and will be suppressed. In this case, each trace of the total record is conditionally attached to the point m of intersection of concentric circles with the profile. To obtain the next record (seismograms), the point of explosion with all secondary groups of receiver receivers is shifted to a distance at which the arrangements of neighboring secondary groups overlap with each other, which makes it possible to create a system of coupled years along the lines of synphasms sum: insulated signals, including the MiHoroKpaTHbix system of overlaps. When crossing the Granina profile, the deposits of the object under study do not follow, and thus, after the appropriate processing, the water boundary is established; the gas and gas contact disappears with the infinite frame rate; The method of processing the received seismogram MM is as follows. Repeated summing of signals recorded on seismograms after entering kinematic corrections, in this way, get the value to to from the water-oil-gas contact under investigation along the profile pr; And simultaneously suppressing the multiples. When working out the field profile of the edict in the field, in a separate way, as a result of subsequent processing, a map / o- will be obtained. A velocity analysis of the area will be used to build a velocity map to the contact under study. Finally, a structural map of the oil and gas contact is constructed on the map / speed map. The advantage of this system over known ones is that it realizes the possibility of direct determination and delineation of lore, regardless of the type of structure, with an arbitrary location of the profiles relative to the elements of the strike along the seismic survey data. The system has significant noise immunity and makes it possible to double the summation of useful signals - weak reflections from oil and gas contacts. The first cAMP is carried out under field conditions, with the rear seismic Reflected waves, the second during the processing of the received data. This circumstance makes it possible to more reliably determine the presence of a water-oil and gas contact. The implementation of the proposed method will reduce the number of deep wells with which the reservoir is investigated, which will have a beneficial economic effect. Claims of the Invention System for seismic observations, consisting of a seismic vibration excitation point and a seismic layout platform; my receiver B connected to the recording channels, characterized in that, in order to increase the sensitivity of the system to waves reflected from horizontal boundaries | And In particular, water-oil and gas contacts, seismic receivers are located in concentric circles with the center at the point of excitation of seismic K OCH oscillations, the outputs of seismic receivers located on each of the circles are connected Sources of information received during the survey; examination. 1.Z.mtsova D. P. and others. About the possibility of using seismic prospecting to track water and oil gas-liquid iKOHTHKTOB. Exploration geophysics. 15. “Nedra, 1966, p. 18-24. 2. US patent N ° 2925: 138, cl. 181-05, published. 1960 Center / 7, on / f / IBKZo6n / i