SU1674035A1 - Method of seismic exploration on fields with unstable top part of the profile - Google Patents

Abstract

The invention relates to geophysics and can be used to provide high-resolution seismic surveys when conducting specialized observations on areas with an unstable upper part of the section. The goal is to increase the performance of seismic exploration. The method is implemented by introducing into each well a casing with radiators at the end equipped with a plug and a coupling with holes sealed from the inside of the pipe by an elastic membrane. At the same time, the cable of the generator of current pulses is lowered at the points of excitation to connect its end to the plug of the radiator, and at the points of reception the seismic receivers lowered into the wells are covered with elastic membranes. 4 il.

Description

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The invention relates to high-resolution seismic prospecting (using electric discharge under a zone of low speeds as a source of seismic excitation) and is intended for carrying out specialized observations under conditions when the section is composed of quaffs, soft and loose rocks.

The aim of the invention is to improve the performance of seismic exploration.

Figure 1 shows the projection of the profile path; figure 2 - the location of the casing in the wells; FIG. 3 shows the connection of the end of the cable with the drift of the radiator in the casing; figure 4 - the location of the geophone, embedded in a narrow passage of the coupling.

On the track (Fig. 1), the profile designates the points of excitation 1 and the reception points 2. At the designated points, explosive wells are drilled (Fig. 2) and columns of casing 3 are lowered into them. Each column 3 includes one coupling 4 with an opening m (windows), which are hermetically sealed with an elastic membrane 5 (Fig. 3), which protects the environment from entering the interior of the column 3, and an electric-discharge radiator 6 with a plug 7 (Fig. 4) for connecting it with the lowered end 8 of the cable 9 of the pulse generator current (GIT).

The coupling 4 in the column 3 is placed so that when the column is fixed in the well, it is located in the liquid column (or unstable rock) near the upper boundary. This is necessary so that under the action of davs VI

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liquid 5 (through the through holes of the coupling 4), the membrane 5 narrowed the flow area of the casing 3 so that, on the one hand, when the seismic receiver 10 was dropped (lowered), the membrane 5 covered its body and ensured reliable contact with it, on the other hand, when it lowered cable 9 (when seismic receivers 10 are absent) membrane 5 provided free passage of its end 7.

The use of the proposed method, for example, in the implementation of the technique of multiple overlapping by the method of the total depth of a point (ORT) is performed as follows.

On the profile track at the scheduled points of excitation 1 and reception, the casing 3 is mounted under the zone of low speeds, at the end of which a radiator 6 with a plug 7 is fixed. The casing is used to prevent the wells from flowing. The immersion of the pipes 3 is carried out by the indentation method or by drilling. Then, seismic receptacles 10 are dropped into the casing wells at the corresponding profile station and their wires are connected to the seismic mow, and the cable 9 is lowered into the cased wells located on the profile outlet with the plug 7 of the radiator 6. After that - excitation of seismic waves and their registration is wounded.

As a certain number of wells are developed, columns of pipes with radiators are extracted from them and transported for immersion into the wells of the next section of the profile, i.e. apply the conveyor method of field work.

Claims (1)

Invention Formula A method of seismic exploration in areas with an unstable upper part of the section, including laying a profile, drilling explosive wells, immersing excitation sources in them, arranging seismic receivers on the profile, exciting and recording seismic vibrations, in order to improve the performance of seismic exploration , all the drilled wells are surrounded by columns of pipes, at the lower ends of which they are hermetically sealed by electric-spark sources with the possibility of connection with a pulse generator t Single through the plug, between the casing pipes, which joint is located below the upper level of unstable rocks establish coupling with the through apertures (windows), is hermetically closed by a flexible membrane within, the narrow passage hole which is set seysmop- riemnik. Phage / B Fy