WO2007061333A1

WO2007061333A1 - Acoustic downhole device

Info

Publication number: WO2007061333A1
Application number: PCT/RU2006/000244
Authority: WO
Inventors: Isaak Aronovich Orentlikherman; Ernest Isaakovich Orentlikherman; Anatoly Gennadievich Chaplygin; Nikolai Alexandrovich Maximenkov; Yury Ivanovich Burlyakov
Original assignee: Isaak Aronovich Orentlikherman; Orentlikherman Ernest Isaakovi; Anatoly Gennadievich Chaplygin; Maximenkov Nikolai Alexandrovi; Yury Ivanovich Burlyakov
Priority date: 2005-11-28
Filing date: 2006-05-17
Publication date: 2007-05-31
Also published as: RU2005136751A; EA200600798A1; EA009245B1; RU2301329C2

Abstract

The inventive acoustic downhole device relates to devices for producing acoustical action on productive formations, drilling areas for increasing the flowrate of oil and gas wells and during repair and insulation operations. Said invention makes it possible to increase the acoustic power by automatically tuning frequency and phase equalisation in such a way that the resonance frequency dispersion of piezoelectric converters in each section is compensated. Said acoustic downhole device is powered by a direct-current power supply and consists of several independent sections operating on the natural resonance frequency thereof. Each section is located in a sealed body and comprises a service power supply, filter module, protective module, master generator, AFC module and a phase adjuster for compensating the resonance frequency dispersion of the piezoelectric converters, a power module, current transformer, adder, feedback sensor, at least two piezoelectric converters which are pre-selected according to a resonance frequency and each of which is provided with its own control channel consisting of the feedback sensor, phase adjuster, power module and the current transformer.

Description

ACOUSTIC Borehole DEVICE.

1. Field of technology. The invention relates to devices for acoustic impact on reservoirs, perforation zones to increase the debit of oil and gas wells and conduct repair and insulation works.

2. The prior art.

A well-known acoustic borehole device (patent RU Na 2152513), comprising an acoustic emitter and an electronics unit with the possibility of continuous monitoring and adjustment of acoustic exposure modes.

The disadvantage of the device is the lack of frequency adjustment of individual piezoelectric transducers, which does not allow the use of the device with maximum power. A well-known acoustic borehole device (patent RU Ne 2260688), containing a sealed enclosure with an electronics unit and piezoelectric transducers placed in it, the electronics unit is equipped with a master oscillator, a power amplifier, an overvoltage protection module, a current transformer, while the generator generates signals with a varying frequency in the range determined during the operation of the device in the well at the minimum and maximum resonant frequencies of the piezoelectric transducers that make up the device. ₍

The disadvantage of the device with the indicated method of frequency tuning is the loss of the output radiated power during the transition from one resonant frequency to another, when none of the piezoelectric transducers does not work in resonance. Another disadvantage is the use of industrial frequency for powering the downhole tool, which leads to a complication of the design, reduced reliability and poor performance of the device, due to an increase in the mass-dimensional characteristics of the device,

SUBSTITUTE SHEET (RULE 26) application in the device of additional chokes, rectifying elements, capacitors, etc.

Also known, adopted for the prototype, acoustic downhole emitter (patent RU Na 2193651, 11/23/2001), containing the upper head with

5 a contact device for a cable lug, a sealed enclosure with an electronics unit and piezoelectric transducers from longitudinally polarized piezoceramic washers placed in it, several washers are made with segments electrically isolated from the rest of the washers, acting as built-in feedback sensors. The disadvantage of the emitter is the deviation from resonant frequencies under the influence of well conditions (external pressure, elevated temperature, vibration, etc.) and due to this loss of acoustic power. Loss of electrical power due to the location of the power source in the ground unit and losses in the cable when transmitting a high-frequency signal from the ground

15 equipment to the emitter, lack of protection against overloads. The inability to simultaneously use different frequency modules and use a given set of frequencies with one descent. Insufficient reliability due to placement in one housing. 3. The invention.

20 3.1. An object of the invention is to increase the acoustic power of the downhole tool, increase reliability and ensure the use of different frequencies simultaneously with one descent.

The technical result of the invention is an increase in acoustic power due to:

25 - reducing losses in the cable of electric power supplied to the downhole tool, due to the constant voltage supply of the master oscillator and the power module, located in the same housing with piezoelectric transducers,

SUBSTITUTE SHEET (RULE 26) - automatic frequency adjustment and phase correction to compensate for the spread of the resonant frequencies of the piezoelectric transducers in each section.

Improving the reliability of the device is ensured by the independent operation of 5 of each piezoelectric transducer and each section.

The problem of the simultaneous use of different-frequency modules and the use of a given set of frequencies at one descent, as well as the improvement of maintainability and ease of maintenance of the device during operation and repair due to the modularity of design, solved 3.2. Features.

Unlike the known device, the acoustic downhole device is powered from a direct current source and consists of several independent sections operating at their own resonant frequency. Each section is housed in a sealed enclosure and contains a service power supply, 15 filter modules, a protection module, a master oscillator, an AFC module and a phase corrector to compensate for the spread of the resonant frequencies of piezoelectric transducers, a power module, a current transformer, an adder, a feedback sensor, at least two previously selected according to the resonant frequency of the piezoelectric transducers, each of the piezoelectric transducers 0 has its own control channel, consisting of a feedback sensor, phase corrector, power module, current ransformatora.

In this case, an acoustic borehole device may contain three sections operating simultaneously at different resonant frequencies, for example, 15 ± 10%, 20 ± 10%, 35 ± 10% kHz, or at one resonant frequency. 5 A remote sensor that measures acoustic vibrations can be used as a feedback sensor.

3.3. The list of figures drawings.

Figure 1 presents a diagram of the design of the device;

In FIG. 2 is a block diagram of a section;

SUBSTITUTE SHEET (RULE 26) In FIG. 3 shows a graph of the dependence of the acoustic power P _ao on the supplied frequency during operation of the section without phase correction;

In FIG. 4 is a graph of the dependence of the acoustic power P _ac on the supplied frequency during operation of the section with phase correction,

5 where pos. 1 - geophysical cable, pos. 2 - upper head, pos. 3 - section housing, pos. 4 - the place of the sealed connection of the sections, pos. 5 - end cap, pos. 6, 7, 8 - electronic modules, pos. 9 - piezoelectric transducers, pos. 10 - filter module, pos. 11 - protection module, pos. 12 - service power supply, pos. 13 - master oscillator, pos. 14 - module ιо AFC, pos. 15 - phase corrector, pos. 16 - power module, pos. 17 - current transformer, pos. 18 - adder, pos. 19 - feedback sensor; pos. 20, 21, 22 - the power of the piezoelectric transducers at the operating frequency; Fl, F2, FЗ are the natural resonant frequencies of piezoelectric transducers, Fr, FrI, Fr2, FrЗ are the operating frequencies of the section.

15 4. Information confirming the possibility of carrying out the invention.

Acoustic borehole device (Fig. 1) consists of one or several sections made in hollow sealed metal cylindrical cases 3, hermetically connected to each other 4, upper

20 heads 2 with a contact device for the cable lug of the geophysical cable 1 hermetically connected to the upper section and the end cap 5.

The sections are placed in sealed enclosures, interconnected by means of a sealed docking unit 4, which provides protection for the entire device in case of failure of any section, as well as the ability to

25 modules at its pre-set frequency.

Piezoelectric transducers 9 (at least two pieces) and electronic modules 6,7,8 are placed in the case of section 3. Piezoelectric transducers are located in one plane perpendicular to the vertical axis of the section. The electronic modules are made in the form of functionally complete blocks for the quick replacement of the spare parts in necessary cases, which significantly reduces the repair time.

SUBSTITUTE SHEET (RULE 26) Piezoelectric transducers consist of longitudinally polarized, electrically connected in parallel piezoceramic washers and include at least two piezoceramic washers with segments electrically isolated from the rest of the surface, acting as built-in sensors for monitoring the operation and tuning the parameters of the piezoelectric transducer. The piezoelectric transducer has a finished design, with pre-tensioned washers using a threaded rod at both ends and pads.

As a feedback sensor, the selected segment on the piezoelectric transducer washer is used; in the absence of the selected segments, an external sensor can be used that measures the acoustic vibrations emitted by the piezoelectric transducer.

The tightness of the installation of piezoelectric transducers in the housing is ensured, for example, by gland assemblies using rubber sealing rings.

Electronic modules 6,7,8 are placed in section 3 in such a way (distributed over the entire volume of the section housing) in order to provide better cooling of the power elements and reduce the length of the section, which leads to an increase in the specific acoustic power of the device as a whole. Electronic modules 6,7,8 perform the function of automatic tuning to the resonant frequency of the piezoelectric transducer, with automatic correction of the frequency and phase of other piezoelectric transducers in this section.

Electronic modules 6,7,8 include a service power supply 12, a filter module 10, a protection module 11, a master oscillator 13, an AFC module 14 and a phase corrector 15, to compensate for the spread of the resonant frequencies of the piezoelectric transducers, a power module 16, a current transformer 17, an adder 18 feedback sensor 19. In this case, the control channel, consisting of the feedback sensor 19, phase corrector 15, power module 16, current transformer 17 serves to operate a separate piezoelectric transducer.

SUBSTITUTE SHEET (RULE 26) The feedback sensors 19 of the piezoelectric transducers are independently connected to the phase correction modules 15 (Fig. 2). The signal from each sensor is processed in the phase correction modules in terms of amplitude and phase of the piezoelectric transducers taken during operation 9.

5 Operation of the device.

The stabilized DC voltage is supplied through the geophysical cable 1 (Fig 1.) to the filter module 10 (Fig 2.). The filter module has a large constant time component, in order to reduce high voltage ripple and filter high-frequency frequencies from the service power supply. From the filter module 10, the supply voltage is distributed to the service power supply 12 and to the protection module 11. From the protection module 11, the voltage is supplied to the power modules 16. The service power supply 12 provides the operation of low-voltage elements included in all electronic modules.

15 Protection module 11 is designed to protect power elements from overvoltage during a sharp disconnection of the load and an increased value of the consumed current, as well as during a short circuit in power circuits and the load.

Power modules 16 form a powerful high-frequency signal,

20 is acceptable for supplying piezoelectric transducers, which through current transformers 17 enters the piezoelectric transducers 9 and the current adder 18. Moreover, current transformers 17 have two-way communication for determining the phase and protecting against overloading the piezoelectric transducers, followed by disconnecting a particular piezoelectric transducer. From the output of the adder, the signal goes to

25 AFC module 14. In the AFC module, a piezo transducer is captured at the lower resonant frequency. The error signal from the AFC module 14 is fed to the master oscillator 13, where stabilization (automatic frequency adjustment) of the master oscillator occurs.

The signal from the master oscillator 13, pre-tuned to the middle frequency of the piezoelectric transducers in the section, comes through phase

SUBSTITUTE SHEET (RULE 26) correctors 15 to the power modules 16. At the first moment of operation, in the phase correction module 15, the signal has a maximum phase shift for all piezoelectric transducers in order to determine and capture the AFC of the lowest frequency from the adder 18. After the frequency is captured, the phase corrector 15 eliminates the 5 error for the piezoelectric transducers 9 having a higher frequency. The work of the phase corrector 15 is based on dynamic tracking and correction of the error between the captured lowest frequency of the master oscillator 13 and the increased resonant frequency of the piezoelectric transducers 9 along the pulse front from the feedback sensors 19. In this case, the time interval, vo in which the error correction occurs, is selected depending on applied design of piezoelectric transducers.

Thus, the frequency is reduced for piezoelectric transducers 9 with an increased resonant frequency in an insignificant range of resonant frequencies. The feedback sensors 19 determine

15 also the amplitude of the signal of the piezoelectric transducer, and with a large difference in the amplitudes of the oscillations of the piezoelectric transducers (associated with the different impedance of the piezoelectric transducers in the manufacture, environmental exposure - temperature, pressure), the phase corrector 15 equalizes the signals arriving at the power module 16, thereby achieving uniform distribution of the signal across

20 piezoelectric transducers 9.

Thus, there is an automatic adjustment of the parameters (frequency, voltage, phase shift) of the electrical signals supplied to the piezoelectric transducers 9, in order to maximize the acoustic impact on the well, bottom-hole zone, formation.

25 The body parts of the borehole acoustic emitter are made of material that ensures the operation of the device in a specific environment. Piezoelectric transducer washers are made, for example, from PKR-78 ceramics. Electronic modules are made on common industrial elements. A geophysical cable is used, for example, KP-60-180-1 s

30 tip type NKBZ -36.

SUBSTITUTE SHEET (RULE 26)

Claims

CLAIM

1. Acoustic borehole device, comprising an upper head with a contact device for a cable lug, a sealed enclosure with an electronics unit housed in it, and piezoelectric transducers from

5 longitudinally polarized, electrically connected in parallel piezoelectric washers, at least two washers are made with segments electrically isolated from the rest of the washer segments acting as feedback sensors, piezoelectric transducers are placed perpendicular to the longitudinal axis of the emitter and are made with overlays, whose working surface is in direct contact with the surrounding medium, piezoelectric transducers are electrically and mechanically independent of each other, characterized in that the acoustic device Azhinov powered by DC and consists of several independent operating at self-resonant sections, each section

15 is placed in a sealed enclosure and contains a service power supply, a filter module, a protection module, a master oscillator, an AFC module and a phase corrector to compensate for the spread of the resonant frequencies of the piezoelectric transducers, a power module, a current transformer, an adder, a feedback sensor, at least two pre-selected resonant

20 frequency of the piezoelectric transducers, while each of the piezoelectric transducers has its own control channel, consisting of a feedback sensor, phase corrector, power module, current transformer.

2. The device according to claim 1, characterized in that it contains three sections operating simultaneously at resonant frequencies, for example, 15 ± 10%,

25 20 ± 10%, 35 ± 10% kHz.

3. The device according to claim 1, characterized in that it comprises sections operating simultaneously at one resonant frequency.

4. The device according to claim 1, characterized in that an external sensor measuring acoustic vibrations is used as a feedback sensor. zo

SUBSTITUTE SHEET (RULE 26)