SU1413568A1 - Acoustic sonde of downhole instrument - Google Patents

Abstract

This invention relates to a technique for downhole geophysical surveys. The goal is to simplify the design, increase reliability and improve the operational characteristics of the probe. An acoustic probe, together with an electronics unit, receivers placed in an enclosure, and centralizers, constitute a downhole acoustic logging tool lowered on the logging cable to measure the acoustic characteristics of the rock crossed by the well. New in the probe is that the hermetic shell on the site of the receivers is made in the form of a rigid pipe. The pipe is fixedly connected at one end to the mounting and supporting insulators, and installed on the rest of the length with respect to them with a slip w; contact, with respect to the supporting insulator, this is ensured by means of the supporting discs evenly placed along the length. The pressure compensator is designed as a deformable tube of non-circular cross section. 1 hp f-ly, 4 ill. (/; with

Description

The invention relates to a technique for - downhole geophysical surveys.

The aim of the invention is to simplify the design, increase the reliability and improve the operational characteristics of the acoustic probe of the downhole tool.

Fig, 1 shows a downhole tool with an acoustic probe, a general view; in fig. 2 - acoustic probe, incision; in fig. 3 - node I in FIG. 2,; FIG. 4 — deformable tube used as a pressure compensator, cross section, variants.

The acoustic probe 1, together with the electronics unit, placed in the guard casing 2, and centralizers 3 and 4, constitutes a downhole acoustic logging tool, run-down on the logging cable, to measure the acoustic characteristics of the crossed rocks of the well. Acoustic probe 1 contains a magnetostrictor emitter 5 installed through sound-insulating layers on rod 6 with aperture 7. Thin-walled steel sleeve 8 externally separates the cavity of the emitter, filled with electrically insulating liquid, and bridge 9 with hermetic pass-through electrical leads 10 separates it. from the electronics unit, placed in the protective housing 2. The rod 6 through the adapter 11 is connected with the supporting acoustic insulator 12, made in the form of a rigid pipe with through mutually overlapping along the forming slots. A flange 13 is fastened to the insulator 12, the fitting 14 of which is fixed to the adjusting bushes 15 and 16 receivers 17 and 18, separated by an installation acoustic insulator 19, made in the form of a cylindrical coil spring. By adjusting the sleeves 15 and 16, the distance between the receivers is established with the necessary accuracy - the measurement base.

The hermetic shell 20, which is filled in the form of a rigid pipe made of a material with a low velocity of elastic oscillations, such as templen, fluoroplastic, separates-; Receiver placement from the environment and holds them along the axis

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devices. The outer diameter of the casing 20 is reinforced by the supporting discs 21 uniformly distributed along the length, fixed in the supporting insulator 12. At the same time, the casing 20 is installed in the supporting discs 21 with a sliding contact and insulator 19 and adjusting bushings 15 and 16. Cork

22 closes the shell 20 from the upper end.

Such constructive execution of the receiver assembly provides the ability to install three (or more) receivers with a small measurement base and precise adjustment of its size. This increases the reliability of geological information in a thin layer of the cut due to simultaneous measurements on several (for example, two) bases.

The hermetic casing 20 with the receivers 17 and 18 and the cavity where the radiator 5 is located are filled with electrically insulating liquid and through fittings

23 and 24 in the plug 22 and the adapter 11 are connected by a deformable non-circular tube 25, which is a pressure compensator. The ends of the tube are sealed and secured in the connected fittings with the help of elastic elements 26 and 27 in the annular cylindrical gap between the seating surface of the fittings and the rigid sleeve 28 inserted into the tube with outer grooves 29, one of which is fitted with an elastic sealing element 26, and the second interacts with mounted outside the tube with a split elastic ring 30, compressible when screwing the cap nuts 31 on the fittings.

One-piece hermetic fastening of the ends of a deformable tube 25 made of polymeric materials -. Fishing, for example, fluoroplastics, on the connected fittings, is provided by its hot-landing on the surfaces of the ends of the fittings at a tension of 20 to 30%.

The presence of a single hydraulic channel connecting the cavities of the placement of the radiator 5 and the receivers 17 and 18 ensures reliable transmission of the acoustic signal between the electroacoustic transducers and reduces the performance of the device in ground conditions.

without the use of a special sound cable.

The wires from the receivers 17 and 18 are inserted into the central holes 32 and 33 of the sleeves 15 and 16, pass inside the deformable tube 25, into the central hole 7 of the rod 6 and through the central group of hermetic pass-through electrical leads 10 are connected to the input circuits of the amplifier of the electronics unit.

The wires from the receivers and the radiator are separated by a screen (not shown) to eliminate the electromagnetic on. vodka from radiation pulse.

Longitudinal grooves 34 and 35 in the carrier: insulator 12 provide free passage of elastic waves without noticeable distortion to the receivers 17 and 18.

The acoustic probe works in a consistent manner.

Increasing pressure of flushing fluid when lowering into the well.

of the supporting discs 21, the mounting insulator 19, the adjusting sleeves 15 and 16, and the receivers 17 and 18, the distance between which in the whole range of temperature variation is measurable, is within the range of 0.4 - П, 5% and does not depend on the change shell length 20,

Q When applying the excitation pulse to the winding of the emitter 5, the elastic oscillations generated by it through the walls of the sleeve 8, the washing fluid is transmitted to the borehole walls, passing 5 D t to the receivers 17 and 18, they are converted into electrical signals that are transmitted to the electronics unit and after amplification cable to land equipment for

Q processing and registration.

Claims (2)

Claim 1. Borehole acoustic probe thirty acts on the walls of the tube 25, the deformer-25 of the device, which contains electroacoustic it in such a way that the area of the cross section bounded by it is reduced in proportion to the decrease in the volume of the electrically insulating liquid filling the internal cavities. When the temperature rises, when the expansion of the electrically insulating fluid exceeds its compressibility value under the action of pressure, the tube 25 expands with internal pressure, its cross-sectional shape gradually rounds, approaching the circle shape. With an increase in temperature, the length of the hermetic shell 20 made of polymeric materials increases by an order of magnitude as compared with parts made of metal. In the range of operating temperatures up to a change in length reaches 5%. In this device, the hermetic shell 20 is fixedly connected at one end (upper in FIG. 2) through the flange 13 to the carrier 12 and the mounting 19 acoustic insulators, and in the rest of the length is installed with respect to them with a sliding contact. Therefore, a change in the length causes a movement of its free end 40 45 50 Transducers-emitters and receivers separated by parallel-fitted supporting and mounting acoustic insulators and placed in a sealed enclosure filled with an electrically insulating liquid, communicated with a pressure compensator, and the sealed enclosure is installed coaxially in a supporting insulator, characterized in that, in order to simplify the design , increasing the reliability and improving the operational characteristics of the probe, the hermetic shell at the receiver placement area is made in the form of a rigid pipe. of a material with a low velocity of propagation of elastic waves, is fixed at one end to the mounting and carrying insulators, and the rest of the length is set in relation to them with a sliding contact, and in relation to the supporting insulator by installing rigidly connected with it placed along the length of the supports. 2. A probe according to Claim 1, characterized in that the pressure compensator is made in the form of a deformable tube of non-circular cross section. 0 5 device containing electro-acoustic five 0 five 0 Transducers-emitters and receivers separated by parallel-fitted supporting and mounting acoustic insulators and placed in a sealed enclosure filled with an electrically insulating liquid, communicated with a pressure compensator, and the sealed enclosure is installed coaxially in a supporting insulator, characterized in that, in order to simplify the design , increasing the reliability and improving the operational characteristics of the probe, the hermetic shell at the receiver placement area is made in the form of a rigid pipe. of a material with a low velocity of propagation of elastic waves, is fixed at one end to the mounting and carrying insulators, and the rest of the length is set in relation to them with a sliding contact, and in relation to the supporting insulator by installing rigidly connected with it placed along the length of the supports. 2. A probe according to Claim 1, characterized in that the pressure compensator is made in the form of a deformable tube of non-circular cross section. Y FIG. Xx Ж 34 М - 25 Jj : Y-to 75 y 7 3 Thebes. g FC Fig.if