RU2521094C1 - Acoustic downhole emitter - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: acoustic downhole emitter contains an electronic unit, the upper head ensuring connection to a cable terminal connector, the lower head, a channel for electric wires and metal tight bodies interconnected into the whole structure with piezoelectric transducers placed in them. Inner and outer surface of each body has groove-shaped caves. At that in the bodies there are bushings with screw nuts fixed to them so that the two neighbouring bodies can be fixed towards each other by means of metal wires fixed to two screw nuts of the neighbouring bodies simultaneously. Besides the bodies are also fixed to each other by parts formed by moulding of a rubber-plastic compound at joints of a gap between the two neighbouring bodies.

EFFECT: improvement of efficiency in impact on the well due to a higher efficiency factor of emission in radial direction and generation of a continuous acoustic wave, provision of treatment for horizontal bores and offshoots.

5 cl, 1 dwg

Description

The invention relates to the field of oil and gas industry, in particular to devices for acoustic impact on reservoirs, including for the intensification of oil, water and other fluids from wells.

From the "prior art" known acoustic downhole emitter, which contains an upper head with a contact device for a cable lug, lower head, sealed housing. The housing contains an electronics unit, piezoelectric transducers made of longitudinally polarized, electrically connected in parallel piezoelectric washers. Several washers are made with segments electrically isolated from the rest of the washer surface. Piezoelectric transducers are placed perpendicular to the longitudinal axis of the emitter and are made with overlays. The working surface of the pads is in direct contact with the environment. Piezoelectric transducers are electrically and mechanically independent of each other and placed with rotation from each other at an angle from 0 to 180 °. The pads do not protrude beyond the generatrix of the cylinder described around the emitter body. The working surface of the pads is made flat, or convex, or concave. The housing in which the piezoelectric transducers are located is made of metal in the form of a cylinder or a multifaceted parallelepiped with sealing units in the form of stuffing boxes. Piezoceramic washers installed pre-stressed (see RF patent No. 2193651, publ. 11/27/2002).

The disadvantages of the known device are the following:

- the inability to handle horizontal shafts and the descent into the production string due to the lack of tubing in the well;

- the inability to use the device in the side trunks due to the large diameter of the emitter;

- increase in processing time due to the small length of the emitter;

- lack of a continuous acoustic wave - narrowly directed waves are emitted;

- low throughput in the curved sections of the well during the transition to the sidetrack and to the horizontal section.

In addition, a borehole acoustic emitter is also known from the prior art, which comprises piezoelectric transducers of piezoceramic washers located in metal sealed enclosures. Piezoelectric transducers are placed in pairs in several, at least two, bearing housings that withstand external borehole pressure, the housings are connected in a single sealed structure using metal coils having threads at the ends and at least two radial type sealing elements. In this case, the piezoelectric transducers have insulating pads at the ends. Moreover, the pads are made of the same material as the piezoceramic washers, the piezoelectric transducers are placed in a thin-walled tube made of insulating material and have an internal central channel for laying electric wires passing through hollow insulating split sleeves installed from the ends of the piezoelectric transducers, which simultaneously serve to center the piezoelectric transducers buildings. Moreover, the cases and coils have an external annular groove located symmetrically relative to their center and providing a disk-shaped shape of the directivity of acoustic radiation (see RF patent No. 34406, publ. 10.12.2003).

The disadvantages of the known device are the lack of the ability to process horizontal and sidetracks and low throughput in curved sections of the well when moving to the sidetrack and horizontal section, as well as low radiation efficiency in the radial direction.

The objective of the present invention is to remedy all of the above disadvantages.

The technical result consists in increasing the effectiveness of the impact on the well by obtaining high radiation efficiency in the radial direction and creating a continuous acoustic wave, ensuring the processing of horizontal and lateral shafts, and by operating the device in a production casing without lowering the tubing.

The technical result is ensured by the fact that the downhole acoustic device contains an electronics unit, an upper head that provides a connection with a contact device for a cable lug, a lower head, a channel for electrical wires and metal tight enclosures connected to each other in a single structure, in which piezoelectric transducers are placed. The outer and inner surfaces of each casing have grooves in the form of a groove. At the same time, bushings are installed in the housings with nuts attached to them, made with the possibility of attaching and fixing to each other two adjacent housings by means of metal cables attached simultaneously to two nuts of the neighboring housings. In addition, the housings are also connected to each other by means of parts formed by pouring the rubber-plastic composition at the joints with the gap of two adjacent housings.

In accordance with particular cases of implementation of the present invention has the following design features.

The housings are sealed with elastic gaskets and plugs.

Piezoelectric transducers are equipped with rubber-metal gaskets.

The sleeve is made with the possibility of placing plugs in its hole and provides, together with the coupling screws, piezo transducers and rubber-metal gaskets fastened together.

Piezoelectric transducers are placed in each case with an offset of 90 ° relative to each other.

The essence of the present invention is illustrated by the illustration, which shows a longitudinal section of the device.

The following structural elements are displayed in the illustration:

1 - downhole acoustic device;

2 - case;

3 - piezoelectric transducer;

4 - coupling screw;

5 - rubber-metal gasket;

6 - laying;

7 - sleeve;

8 - a part formed by pouring rubber-plastic

composition;

9 - a metal cable;

10 - a nut;

11 - electric wires;

12 - connecting node;

13 - screw;

14 - a nut;

15 - cork.

The present device 1 includes an upper head, which provides connection with a contact device for a cable lug, a lower head, metal tight housings 2 connected to each other in a single structure, in which piezoelectric transducers 3 are placed in pairs with an offset of 90 ° from each other. Piezoelectric transducers 3 consist of longitudinally polarized, electrically connected piezoceramic washers (5 pcs. In each piezoelectric transducer). Piezoelectric transducers 3 are fastened together by clamping screws 4 (4 pcs.). Rubber-metal gaskets are installed between the piezoelectric transducers 5. For reliable fixation of the piezoelectric transducers 3, bushings 7 are installed in the housing 2, to which the clamping screws 4 are attached.

This device provides independent operation of each piezoelectric transducer 3 located in the housing 2. This is due to the relative position of the piezoelectric transducers 3, as well as the presence of rubber-metal gaskets 5. Such a structural embodiment allows to increase the selectivity of acoustic impact on the well, bottom hole zone, formation.

The upper and lower cases 2 are interconnected by metal cables 9 (4 pcs.) And part 8, formed by rubber-plastic filling of the junction of the two buildings 2 with a small gap. This design provides flexibility that allows you to freely pass the curved sections of the well. In addition, the connection of the housings 2 using metal cables and parts 8 provides an increase in the lateral compliance of the housings 2, which increases the radiation efficiency in the radial direction. Such a device also has a longer service life, since the flexible connection of the housings 2 eliminates its destruction under the action of high pressure in the well and makes the device less fragile.

The fastening and sealing of the housing 2 occurs due to compression and expansion in the radial direction of the rubber gasket 6 with compression nuts 10, which are attached to the bushings 7 (screwed or welded). The hooks 10 have protruding parts, which ensure the attachment of metal cables to them 9. Of these, a loop (closed connection) is made, which simultaneously slips on the protruding parts of the nuts 10 located in two adjacent housings 2.

Piezoceramic washers are fastened together using metal washers, screw 13 and nut 14. Pre-voltage of piezoceramic washers is carried out using screw 13 and nut 14. Using the specified voltage, it is possible to adjust the resonance frequency and impedance value of each piezoelectric transducer 3 to the required values at the moment assembly.

Additional sealing and fastening of the buildings 2 is provided by rubber-plastic pouring 8 at the junction of two adjacent buildings 2.

The power supply to the piezoelectric transducers is supplied via wires 11, which pass through a channel for electric wires. The piezoelectric transducers 3 are connected to the wires 11 in a parallel circuit. The wires 11 between two adjacent buildings 2 are connected using standard geophysical connecting nodes ("five-copecks") 12 and filled with rubber-plastic. To prevent rubber from entering the housing 2 into the cylindrical holes of the bushings 7, rubber plugs 15 are installed.

The outer and inner surfaces of the housing 2 may have grooves in the form of a groove that are milled along the length of the housing 2 (not shown in the figure). The presence of such recesses provides a certain directivity of acoustic radiation, and also leads to lateral compliance of the housing 2. Such a structural embodiment allows to obtain radiation in the radial direction.

The electronics unit is hermetically connected to the housing 2 (not shown in the figure), designed to generate a signal with the working frequency of the piezoelectric transducers 3 and for automatically adjusting the parameters of the piezoelectric transducers 3 (frequency, voltage, phase shift) directly during operation, depending on the processing results in the unit electronics of signals taken from the built-in sensors for monitoring the operation of piezoelectric transducers 3.

The body parts of the borehole acoustic device are made of stainless steel of various grades (for example: 95X18) and aluminum alloys. The washers of the piezoelectric transducers 3 are made of ceramic PKR-78. The electronics unit is made on common industrial elements.

The present device can be used as follows.

Fully mounted and connected to the ground equipment, the downhole acoustic device 1 is subjected to a functional test, while the ground equipment operates in the diagnostic mode and gives a message about the nature of the malfunction or confirms the possibility of operation. After that, it is lowered into the well and power is turned on.

Industrial voltage, after transformations in the ground unit (frequency, voltage, current, phase shift), is supplied through a geophysical cable or umbilical to a borehole acoustic device 1. Voltage, through an electronics unit, is supplied to piezoelectric transducers 3, where, due to the piezoelectric effect, acoustic vibrations, the mechanical energy of which acts directly on the casing 2. In turn, the casing 2 transmits the acoustic wave directly to the environment surrounding the emitter.

Under the influence of pressure in the segments isolated from the rest of the surface of the piezoceramic washers (pressure sensors), an electrical signal appears which enters the electronics unit, as a result of which the parameters (frequency, voltage, phase shift) of the electrical signals supplied to the piezoelectric transducers 3 are adjusted to the maximization side acoustic impact on the well, bottom-hole zone, layer.

Claims (5)

1. A downhole acoustic device comprising an electronics unit, an upper head providing connection with a contact device for a cable lug, a lower head, a channel for electrical wires and metal sealed enclosures connected to each other in a single structure, in which piezoelectric transducers are located, characterized in that the external and the inner surface of each case has grooves in the form of a groove, while bushings with nuts attached to them are installed in the bodies, and connecting and fixing to each other two adjacent housings by means of metal cables attached simultaneously to two nuts of adjacent housings, in addition, the housings are also connected to each other by means of parts formed by filling the rubber-plastic composition at the joints with the gap of two neighboring housings. 2. The device according to claim 1, characterized in that the cases are sealed with elastic gaskets and plugs. 3. The device according to claim 2, characterized in that the piezoelectric transducers are equipped with rubber-metal gaskets. 4. The device according to claim 3, characterized in that the sleeve is arranged to accommodate plugs in its opening and provides, together with the coupling screws, piezo transducers and rubber-metal gaskets fastened together. 5. The device according to any one of claims 1 to 4, characterized in that the piezoelectric transducers are placed in each housing with an offset of 90 ° relative to each other.