SU668451A1 - Method of sea seismic prospecting - Google Patents

Abstract

A METHOD OF SEA SEISMIC EXPLORATION, including laying the seismic spit on the bottom of the profile on each bottom, exciting the oscillations and recording reflections, waves, and the fact that, in order to improve the accuracy of exploration, the excitation of the oscillations is performed around the perimeter of two The mountaineers who have • a common base side coinciding in direction with the longitudinal profile, and the length of the base side is equal to the length of the reception ^ gyks of the braid. "/. • ^

Description

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The invention relates to marine. seismic exploration and maybe

Isolation in a detailed investigation.

The known method of marine seismic 5 rtkkk, with a lac-icSfSJ Siy ™; The spatial observing system is observed in the process of the simultaneous development of 1H of 1 t GIfVD of the profiles associated with the item. By excitation of C, the distance between the profiles can be arbitrary;

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The braid is transported by two vessels moving in the same direction with the same: at 6th speed. 15 Seismic excitations are alternately performed at a time interval sufficient for the 3ai5erHefpHpoBaftnCb oscillations from the previous excitement .20 As a result of this system, three profiles are obtained on, two of which will be received;

points located by longitudinal profiles. 11th yearEarly data YariYtomCharacter eh Gsi ydvyaeinm

statistical effect.

However, the possibilities of spatial interpretations of S tffosome are limited due to the small number of profiles (three) and the distances between them.

The closest in technical essence to the invention is a method of marine seismic expansion,; Including the laying on the bottom of the seismic spit ya to each stand of the profile, the oscillation exclusion and recording

reflected waves 2.

However, according to the method, ensure that only longitudinal and separate non-long-length profiles are obtained, i.e. the seismic 4ecfke received in this case is material predstavlyySGy clearly j

those that are not sufficient for spatial material and the hilly only provide a slight improvement in the quality of the recording along the longitudinal profile due to the statistical summation of additional non-longitudinal; profiles.

The aim of the invention is to improve the intelligence survey by simultaneously obtaining the data of the 55 YOG progressed and incompletely about the CDP profiles, as well as the broad profile of the search for any site,

668451

the number of components of the spatial profiles and the distances between them.

The goal is achieved by the fact that the excitation of oscillations is carried out on 11IER1 of two rectangles, having a common base, which coincides in direction with the length of the 1M profile, and the length of the basic structure.

FIG. Figure 1 shows a general view of the excitation and reception system of oscillations, which is located next to the proposed method in the first arrangement, corresponding to the beginning of the development of the system; in fig. 2 the same, in the second position, when the base of sources and receivers is shifted to half the length of the arrangement; in fig. 3 - formation of deep points in the plan when the oscillations in the horizontal direction are excited in the first position; in fig. A - the formation of common deep points, which at the second position complement the missing dd of a given multiplicity depth points, Yabluchaemye vzrageah horizontal direction; in fig. 5 - formation of deep points in the area. excitations oscillations SRI On the orthogonal direction in the first position; in fig. 6 - change of the base of the deep points, obtained when oscillations oscillate along orthogonal lines and the formation of continuous bands of deep points, parallel to the central longitudinal profile (in this process, double CGT accumulation is formed); in fig. 7 - system. observation to ensure that the duplicates the repeated suppression of the above mentioned propagating in the plane of the profile.

In accordance with the proposed method, the following is carried out

sequence of operations.

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 The yseyichesky pyezokosu 1 is lowered to the bottom, while the vessel (not shown) is fixed and fixes the position of the braid. The oscillations are excited using the second vessel (not shown) around the perimeters of two rectangles 2 and 3, which have a common base Party 4 that matches. with the direction of the longitudinal pro 1 5 (see Fig. 1. 2). Oscillations excited by the source 6, register piezoelectric bottom spit 1.

After working out according to the indicated scheme of the first position of the spit (see Fig. 1), the base of oscillation excitation and the base of observation s are shifted, for example, by half the length of the spit (see Fig. 2), and the process is repeated.

Parameters of the observation system; the spacing between the points of the excitation source of oscillations of the 6 th horizontal perimeter of the rectangle 2 (or 3), as well as the removal of the center of this rectangle from the longitudinal profile 5, at which the oscillation is recorded: 15 scientific research institutes, is chosen based on the formulas for determining the parameters CHCTiSM GBS. Excitation of oscillations along the sides of the rectangle, parallel to or coinciding with the longitudinal profile 5, 20, provides one pp longitudinal 5 and two non-longitudinal 7 and 8 CDP profiles (see Figs. 3, 4); the excitation of oscillations along the sides of the rectangle 9 orthogonal to the longitudinal-25 profile provides a set of parallel, evenly spaced non-conductive single-pass profiles 10 (Fig. 5, 6). At the same time, such accuracy is achieved in the position of single components of a wide profile (25-50 m - the distance between adjacent profiles), which could not be achieved with a standard technological scheme, due to errors in the pa-. dionavigation profile attachment (± 50 m);

The number of single-trace profiles 10 in this case is determined by the number of excitation points 6 on the orthogonal side of the rectangle 10 (Figs. 5, 6). As a result of working out the observations at the first position, you will receive the data fully 45 times the WGT for the main profile m, and a series of single-track profiles. The position of the second position is determined by the multiplicity of accumulation, which is set for the so series of intermediate non-long-term pros. FIG. Figure 6 shows the second position, which provides for the double accumulation of GBS for this series of profiles. In this case, the system of excitation and reception moves to the length of the longitudinal profile of observations by a distance equal to half the length of the receiving base, and the cycle of observations is repeated.

Thus, the proposed seismic survey method provides, along a given NairavlNy, simultaneous testing of longitudinal and two non-longitudinal CDP profiles, as well as sovokuyn6styu garallelnye profiles n times following, forming a single wide profile In relation to the prototype, this method has an spatial orientation in spatial direction in the form of a single profile. other than longitudinal yrofil, which allows to increase significantly reliability and reliability, i.e. accuracy of geological interpretation of geophysical data.

As an example of the implementation of the proposed method consider; a system that provides for the longitudinal profile of suppression of the most widespread within the Northwestern shelf of the Black Sea is a multiple reflection of wavelength; s, 5 km / s. According to the directivity characteristics for the 1st Vigil of the pressure of these waves, it is specifically selected to use the following system parameters: a 2 km spacing, a summation base t km, a distance between sources and receivers 100 m.

Such a system provides a twelve-sided set of waveforms propagated in the plane of the profile (see Fig. 4).

For the analysis of wave-to-noise interferences to the line of observation outside the plane of the profile, a space system is recommended to eliminate this type of interference. Consisting of 3 profiles with a given multiplicity of accumulation and a series of single trace lines. In this case, oscillations are excited along horizontal lines, located at a distance of 2 km from the central longitudinal profile (coinciding with the position of the bottom spit).

The excitation of oscillations in orthogonal directions is performed, starting with the removal, of the district observation base.

Thus, as a result of the development of this system (see Fig. 3), three main GBS profiles are obtained - one longitudinal

(central) and two erfrost and 42 liy, the main main profile of the group with double-diving. It is advisable to use the obtained data to obtain time sections in different azimuthal sections for the purpose of conducting spatial interpretations, to investigate the transverse gradients of the length of the waves of the disturbance waves and loci from one source to another.

strong perturbations, bitch shrovi time sections in a given range of values of / -At getting a base cut, etc.

The data of spatial observations in the absence of intense multiple waves can also be used to obtain time slices, complementary basic profiles, by summing up records on the selected base.

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Claims (1)

METHOD FOR MARINE SEISMIC EXPLORATION, including laying on the bottom of a seismic streamer at each station of the profile, excitation of oscillations and registration of wave reflection, due to the fact that, in order to increase the accuracy of exploration, the oscillations are excited around the perimeter of two rectangles having. a common base side matching in direction with a longitudinal profile, the length of the base side being equal to the length of the streamer receivers. ; . * i i