UA15037U - Well seismometer - Google Patents

Abstract

The proposed well seismometer contains a cylindrical pneumatic chamber with an elastic cover and measuring converters of seismic signals. Each converter is built into a plate, which is installed symmetrically relative to the longitudinal axis of the chamber. Each plate adjoins, by its convex surface, the corresponding end surface of the chamber and is pressed to this surface by an elastic band.

Description

Description of the invention

The useful model relates to geophysical means of rock massif research and can be used in 2 studying in wells the velocity characteristics of the geological section, inter-well sounding, well logging and seismo-acoustic and seismological studies.

A known device for receiving elastic vibrations |1), containing an elastic cylindrical pneumatic chamber, inside which is a container with seismic transducers, and the ends of the chamber are hermetically closed with cylindrical plugs. On the outer surface of the pneumatic chamber, there are longitudinally installed: a contact plate, 70 rigidly connected to the container, with seismic receivers inside the chamber, and two rigid bars, immovably connected by rods through the body of the chamber and symmetrically located relative to the contact plate and the longitudinal axis of the receiver. The contact plate and rigid bars together provide a certain directionality of the action of the pneumatic chamber, but at the same time, no more than half of the surface of the elastic shell is used for the expansion of the receiver and, accordingly, the expansion of the receiver is limited in wells whose diameter is 1.5-2 times greater than the diameter of 72 device.

The closest to the intended solution in terms of technical essence and the result that is achieved is a borehole seismic receiver of elastic oscillations |2), in which a cylindrical elastic air chamber is located in a cylindrical body, which has a longitudinal cutout for the length of the air chamber. The ends of the pneumatic chamber are hermetically connected to a cylindrical sleeve installed inside it, which is rigidly connected to a container with 20 seismic transducers located outside the pneumatic chamber.

The disadvantage of this design is also the inefficient use of the pneumatic chamber, since a large part of the surface of the elastic shell is covered by the case. As a result, the receiver has a small spacer range, which does not allow its use in wells with a diameter that is 1.52 times greater than the original diameter of the receiver. 29 The proposed useful model is based on the task of creating a borehole seismograph, v. 0/ тв) which due to the proposed design of the device, which ensures effective use of the entire surface of the elastic shell of the pneumatic chamber for the expansion of the receiver in the well, the technical result is achieved - an increase in the expansion range of the seismic receiver in the wells.

The problem is solved by the fact that in the borehole seismic receiver, which contains a pneumatic expansion chamber with a cylindrical shell, hermetically connected at the ends with a cylindrical bushing inside it, and seismic transducers, according to the useful model, located at - 30 to the longitudinal axis of the receiver, the design contains two identical pressure elements with an outer trapezoidal and an inner convex cross-section in the area of connection with the pneumatic chamber and with ends beveled to the longitudinal axis, o are installed symmetrically relative to the longitudinal axis of the receiver and the pneumatic chamber and such that are attracted to it by 35 elastic bandages, and seismic transducers are installed in the body of the pressure elements. --

The design of the seismic receiver well in the initial state (in the absence of pressure in the pneumatic system) and in the working mode (with operating pressure in the pneumatic system) in a section along the longitudinal axial plane is shown, respectively, in Fig. 1 and Fig. 2, and in a section along the transverse plane in the middle part the receiver is shown in Fig. 3 and Fig. 4. "

The device contains a pneumatic chamber consisting of an elastic (rubber) shell 1 and a cylindrical nozzle 2 located C 50 inside it, with which the elastic shell 1 is hermetically connected by end parts. c The pipe 2 is fixed rigidly (by glue) to the electrical line З passing through it, and to

From" its end parts is connected through fittings (not shown in the figures) to the pneumatic main 4. Electric signals of the seismic transducers 6 (three spatial components X, Y and 7), installed in the body of the pressure elements 7, are received through the outlet to the main line Z. These elements are located in to the longitudinal plane of the receiver symmetrically 49 relative to its longitudinal axis and in the initial state of the receiver (without pressure in the pneumatic system of the device) - pulled to the pneumatic chamber by elastic bandages 8. The outer surface of the pressure elements 7 in 4! the cross-section is made in the form of a trapezoid (see Fig. 3 and Fig. 4) with edges beveled to the longitudinal axis of the receiver (see Fig. 1 and Fig. 2). The inner surface of these elements in the area of their connection with the pneumatic chamber o has a profile that is convex to the inside of the cross-section of the element (see Fig. 3 and Fig. 4).

Ge) 20 The device works in the following way.

In the initial state (see Fig. 1 and Fig. 3), the seismic receiver is placed in the well at the required depth, and from the earth's surface through the pneumatic line 4, increased pressure is created in its pneumatic chamber.

As a result, the elastic shell 1 increases in transverse size and, pushing the elements 7 apart, presses them against the walls of the well. At the same time, the entire surface of the elastic shell is stretched without hindrance, thanks to which its diameter can exceed the initial diameter by more than two times. c After conducting seismoacoustic measurements, compressed air is released from the pneumatic system of the seismograph and the elastic shell 1 is inflated to its initial state, and the pressure elements 7 are pulled by elastic bandages 8 to the pneumatic chamber, and the device can be moved to another part of the borehole or pulled out from it. At the same time, the edge parts of the pressure elements 7, beveled to the longitudinal axis of the receiver, exclude the engagement of the device with the irregularities (caverns) of the walls of the well.

Making the inner surface of the pressure elements 7 convex inwards with a cross-section shape in the area of connection with the pneumatic chamber provides a large area of contact of its elastic shell with the pressure elements and, accordingly, a large pressure force of the elements 7 with seismic transducers against the wall 65 of the well. At a working pressure of 1.52 atmospheres in the pneumatic system, elements 7 are pressed against the well wall with a force of 3040 kg, which is sufficient for reliable perception by seismic transducers of high-frequency

(up to 2000 Hz and more) elastic waves.

The symmetry of the location of the pressure elements relative to the longitudinal axis of the receiver ensures effective use of the surface of the elastic shell of the pneumatic chamber and guarantees reliable compression of the pressure elements 7 to the initial state (during the release of pressure in the pneumatic system of the device) with the help of elastic bandages 8. In addition, the pressure elements in the initial state protect the pneumatic chamber from damage during the descent of the device into the well.

The external trapezoidal shape of the cross-section of the pressure elements and the symmetry of their mutual arrangement relative to the longitudinal axis of the device contribute to the stability of the receiver in the split state in the cavity, since its symmetrical support along four lines (see Fig. 4) minimizes the transverse components at the contact of the pneumatic chamber and the pressure elements .

The design of the device, due to the provided through pneumatic and electric mains, allows placing the necessary (taking into account the number of channels of the used recording equipment) number of well receivers on them.

The absence of a direct mechanical connection of the pressure elements with the supporting line determines their acoustic solution with the cable elastic wave-interference in the supporting line.

The simplicity and reliability of the construction of the reduction to the initial state (during the release of pressure in the pneumatic main) of the pressure elements excludes the asymmetry of their initial mutual location.

The compactness of the initial state of the pneumatic chamber allows the seismic receiver to be used in wells with a diameter of 10 mm, and the high degree of increase in the diameter of the elastic shell of the pneumatic chamber ensures reliable separation of the seismic receiver in wells with a diameter of up to 180 mm.

Sources of information 1. A. p. 1278744 USSR, MKI" 01M1/40. Device for receiving elastic vibrations / M.Yu. Bogak, Yu.G.

Myasnikov, USSR - MO 3761081/24-25; Proclaimed 06/28/84; Publ. 23.12.86, Bull. Mo 47. 2. A. p. 1343371 USSR, MKI" 001M1/40. Borehole receiver of elastic oscillations / A.S. Trifonov, USSR. - With

MO 4001392/24-25; Announced on 06.01.86; Publ. 07.10.87, Bull. Mo 37.

Claims (2)

The formula of the invention m Zo so 1. A borehole seismic receiver containing a pneumatic expansion chamber located along the receiver's longitudinal axis with a cylindrical elastic shell, hermetically connected at the ends with a cylindrical sleeve av! inside it, and a seismic transducer, which is distinguished by the fact that the design contains two identical pressure elements with an outer trapezoidal and an inner convex cross-section in the area of connection with the pneumatic chamber and with ends beveled to the longitudinal axis, installed symmetrically with respect to the longitudinal axis of the receiver and pneumatic chamber , and those that are attracted to it by elastic bandages, and seismic transducers are installed in the body of the pressure elements. 2. Borehole seismograph according to claim 1, which is characterized by the fact that the pneumatic chamber is made with an axial "longitudinal hole, with which the seismograph is attached to the electric main. - and? - 1 («c) (95) that 60 b5