RU2453677C1 - Acoustic downhole emitter - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: acoustic downhole emitter contains part (1) of acoustic downhole emitter, which is lowered to the well, N-position commutator (2), power amplifier (3), null element (4), frequency divider (5) with N division factor, N-digit binary counter (6), N-digit shift register (7) and N controlled inverters (8).

EFFECT: enlarging functional capabilities of acoustic downhole emitter by using 2^N systems from N various laws of phase manipulation of acoustic pressure, which leads to improvement of acoustic action efficiency and increase in sonic volume of working medium without increasing emissive power.

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Description

The invention relates to the field of geophysics and applied acoustics and can be used for processing productive zones of oil, gas and water wells in order to increase their productivity.

Known downhole emitter, which contains the active modules, made in the form of piezoelectric packs with end plates, pulled together by a central pin. Active modules are placed along the axis of a rigid sealed metal cylindrical body, soundproof at least in the region of the gaps between the modules, filled with an insulating liquid. Each active module is a piezoelectric pack consisting of piezoceramic washers, conductive metal plates and a central reflector in the form of a massive washer. The piezo pack is mechanically compressed by a central pin. The central reflector of each module is attached using metal fastening pins, for example, by welding to the sealing metal housing of the emitter. This design provides central symmetry of the oscillations relative to the middle of the module length and rigid fixation of the modules in the housing relative to each other. Soundproof windows are made in the housing in the region of the gaps between the ends of the active modules. These windows are protected from the environment by any polymer, such as rubber. To compensate for the thermal expansion of the liquid and external hydrostatic pressure, the metal casing is equipped with a compensator (see the invention “Downhole emitter” according to the patent of the Russian Federation No. 2047280, CL H04R 1/44 from 04/20/94).

A disadvantage of the known downhole emitter is the inefficient use of electromechanical conversion, which is caused by the absence of piezoelectric material in the central part of each module, due to the design of the mount. Another disadvantage of this design is the extremely low maintainability of the device in case of replacement of one or more modules.

Also known acoustic downhole emitter, which contains active modules in the form of piezoelectric packs with end plates tightened by central pins, placed along the axis of a rigid sealed cylindrical housing filled with electrical insulating fluid, soundproof at least in the region of the gaps between the modules; the ends of adjacent modules are mechanically fastened together by spring elements, and the ends of the end modules are connected through spring elements to the end caps of the housing, while the flexibility of each spring element is more than an order of magnitude greater than the flexibility of the volume of the insulating liquid in the gap between the modules, and the power source electrically connected to emitter (see the invention "Acoustic borehole emitter" according to the patent of the Russian Federation No. 2169383, CL H04R 1/44, 06/20/01).

The disadvantage of this acoustic borehole emitter is the presence on its radiating surface of the sites performing antiphase oscillations, which reduces the radiation efficiency in the radial direction. Those are the areas opposite the lateral surface of the piezoelectric packets, and the gaps between the modules. In addition, with a sufficiently high height of the downhole emitter, its radiation becomes directed in the vertical plane, which leads to a decrease in the volume of the working medium irradiated by the emitter and a decrease in the efficiency of its impact on the working medium. To increase the volume of the voiced medium, such an emitter needs to be moved in the vertical direction, which is associated with additional time costs, and in some cases leads to a decrease in the impact efficiency.

The closest in technical essence to the present invention is an acoustic borehole emitter containing active modules in the form of piezoelectric packs with end plates tightened by central studs, placed along the axis of a rigid sealed cylindrical housing filled with electrical insulating fluid and translucent, at least in the region of the gaps between the modules , spring elements that mechanically fasten together the ends of adjacent modules and the ends of the end modules with end caps and, while the flexibility of each spring element is more than an order of magnitude greater than the flexibility of the volume of the insulating liquid in the gap between the active modules, and the power source electrically connected to the emitter is N in the number of piezo-packs of acoustically soft cylindrical screens placed between the side surface of the piezo-packs and the inner surface of the hard sealed cylindrical body, end plates are made frequency-lowering so that the effective speed of sound, which determines the frequency of of resonance in piezoelectric packets with end plates is (1.2-1.3) C, where C is the speed of sound in an external working medium, the distance between the end plates of adjacent modules and the ends of the end modules and the end caps of the housing is (0.2-0.25) λ, where λ - the wavelength of acoustic radiation in an external working medium, and the power source is connected to the emitter by means of a power amplifier, which is made with a symmetric output and is equipped with an N-position switch, the first N inputs / outputs of which are connected to electrical input mi-outputs of N-piezoelectric packets, and the second symmetric output of the power amplifier is connected to the symmetric second input of the N-position switch, and N switch positions correspond to N laws of phase manipulation of sound pressure in (N + 1) translucent gaps of a rigid sealed cylindrical housing, and the distance between centers of translucent gaps is equal to (0.8-0.85) λ (see patent for invention No. 2276475 “Acoustic borehole emitter”, published on 05/10/2006, according to the application 2004129032/28 dated 04.10.2004, class. H04R 1/44).

The disadvantage of this acoustic downhole emitter is a limited set of laws of phase manipulation of sound pressure, since the number of laws of phase manipulation is N. A limited number of laws of phase manipulation allows only N different types of directivity characteristics to be generated in the vertical plane, which significantly limits the volume of the working medium being irradiated. This leads to low acoustic impact on a relatively small volume of the working environment.

The aim of the invention is to expand the functionality of an acoustic downhole emitter by using 2 ^N systems of N different (non-repeating) laws of phase manipulation of sound pressure, which leads to an increase in the efficiency of acoustic exposure and an increase in the voiced volume of the working medium without increasing the radiation power.

This goal is achieved by the fact that in a known acoustic downhole emitter containing active modules in the form of piezoelectric packs with end plates tightened by central pins, placed along the axis of a rigid sealed cylindrical housing filled with electrical insulating fluid and soundproof, at least in the region of the gaps between the modules, spring elements that mechanically fasten together the ends of adjacent modules and the ends of the end modules with end caps of the housing, while the flexibility of each the spring element exceeds the flexibility of the volume of the insulating liquid in the gap between the active modules by more than an order of magnitude, and the power source electrically connected to the emitter is N in terms of the number of piezoelectric packs of acoustically soft cylindrical screens placed between the side surface of the piezoelectric packs and the inner surface of the rigid sealed cylindrical body, end plates made frequency-lowering so that the effective speed of sound, which determines the frequency of the longitudinal resonance in the piezo length with end plates, is (1.2-1.3) C, where C is the speed of sound in an external working environment, the distance between the end plates of adjacent modules and the ends of the end modules and the end caps of the housing is (0.2-0.25) λ, where λ is the wavelength acoustic radiation in an external working environment, the power source is connected to the emitter through a power amplifier, which is made with a symmetric output and equipped with an N-position switch, the second symmetric output of the power amplifier is connected to a symmetric second input of an N-position nth switch, and the distance between the centers (N + 1) of the translucent gaps of the rigid sealed cylindrical body is (0.8-0.85) λ, a zero-organ, a frequency divider with a division coefficient N, an N-bit binary counter, an N-bit shift register, and N controlled inverters, with N outputs of the switch connected to the information inputs of the corresponding controlled inverters, the outputs of which are connected to the electrical inputs of the corresponding piezoelectric packets, the last output of the N-position switch (Walsh functions at the outputs to switch (ordered by the number of alternating signs) is connected to the input of the zero-organ, the output of which is connected to the shift input of the N-bit shift register and the input of the frequency divider with the division coefficient N, the output of the frequency divider with the division coefficient N is connected to the control input of the N-bit shift register and the counting input of the N-bit binary counter, the information outputs of the bits of the N-bit binary counter are connected to the corresponding information inputs of the N-bit shift register, the high-order output is N-times a linear shift register is connected to the control inputs of all controlled inverters.

Figure 1 presents the structural diagram of the proposed acoustic downhole emitter. Figure 2 shows a schematic design of the part of the acoustic downhole emitter lowered into the well. Figure 3 presents a fragment of the emitter part lowered into the well with the active module, spring elements and a soundproof window. Figure 4 presents the timing diagrams of the system of Walsh functions. 5 is a timing diagram illustrating the process of generating a signal S (6, θ) of another derivative of a system of discrete orthogonal signals. Figure 6 presents the timing diagrams of the derivative system of discrete orthogonal signals S (i, θ).

The acoustic downhole emitter (Fig. 1) comprises a downhole acoustic emitter part 1, an N-position switch 2, a power amplifier 3, a zero-organ 4, a frequency divider 5 with a division coefficient N, an N-bit binary counter in, N- bit register 7 shift and N controlled inverters 8.

Part 1 of the acoustic borehole emitter lowered into the well (FIG. 2) and fragments with the active module, spring elements and a translucent window (FIG. 3) included in part 1 of the acoustic borehole emitter contain active modules made in the form of piezoelectric packs 9. Each active module consists of identical piezoceramic washers 10 glued through metal electrodes 11. At the ends of the active part of the module there are metal radiating plates 12. The module along the axis is compressed with a certain force to the central metal Coy reinforcing tightening pin 13 that increases its mechanical strength. The pin 13 is placed inside the piezoelectric packet with a minimum clearance. The active modules are coaxially placed in a metal case 14 having soundproof windows 15. The modules are acoustically isolated from the case using rubber decouples 16, and with the help of flexible rings 17 that provide a rigid fixation of the relative placement of the modules in the case 14, they form a mechanically connected chain. The metal electrodes of each active module are electrically interconnected by wires 18. The first and last flexible rings are mechanically connected to the covers of the housing 19. The housing 14 is sealed with rubber plugs 20, filled with electrical insulating liquid 21 and equipped with a compensator 22. The compensator is mechanically protected by a cap 23. Between the side surface of each the piezoelectric package and the inner surface of the housing 14 are placed acoustically soft cylindrical screens 24, made, for example, of a rigid foam.

As in the prototype, when choosing the distance between the translucent gaps equal to (0.8-0.85) λ, where λ is the wavelength of acoustic radiation in the working medium, the axial concentration coefficient of the acoustic downhole emitter, which determines the efficiency of the directed radiation, becomes maximum.

As in the prototype, for the implementation of an acoustic borehole emitter with such dimensions, it is also necessary to significantly reduce the effective speed of sound, which determines the frequency of the longitudinal resonance of the piezoelectric package with end plates, using them as frequency-reducing. So, for example, if the end plates are made of steel, and their total thickness is (0.2-0.25) of the thickness of the piezoelectric packet, then the effective speed of sound will be (1.2-1.3) C, where C is the speed of sound in the working medium, for example, in sea water , while the value of the translucent gap between the end plates should be (0.2-0.25) λ.

Acoustic downhole emitter operates as follows.

The acoustic emitter part 1 lowered into the well (FIG. 1), connected by a multicore cable to the outputs of the controlled inverters 8 (FIG. 1), is immersed in approximately the middle of the volume of the working medium subject to powerful sound.

Using the N-position switch 2 at its information outputs, a type of phase-shift voltage manipulation is created, described by N Walsh functions Wal (i, θ), similar to how it is done in the prototype (see patent for the invention No. 2276475 “Acoustic borehole emitter”, published May 10, 2006, by application 2004129032/28 of October 4, 2004, CL H04R 1/44).

The disadvantage of the prototype is that it has a limited set of laws of phase manipulation of sound pressure, since the number of laws of phase manipulation is N (where N is the number of Walsh functions in the signal system used, with N = 2 ⁿ , where n = 1, 2 , 3, ...), in the proposed device is eliminated.

Indeed, the proposed acoustic downhole emitter generates 2 ^N systems of discrete orthogonal signals at the outputs of the controlled inverters 8 in turn, and each system is described by N laws of phase manipulation of sound pressure. The Walsh function system will describe the first generated set of laws of phase manipulation of sound pressure in the proposed acoustic downhole emitter, the duration of which is N cycles of operation of the device, at that time when a sequence of the form “00000000” will be recorded in the shift register 7 (for the case N = 8 )

After the formation of the entire system of Walsh functions with a duration of N cycles, the state of the bits of the shift register 7 will change, and a sequence of the form “00000001” will be written in it (for the case N = 8). Over the next N clocks, at the outputs of the controlled inverters 8, a second system of discrete orthogonal signals, different from the system of Walsh functions, will be generated.

After its formation, the state of the bits of the shift register 7 will change, and a sequence of the form “00000010” will be written in it (for the case N = 8). During the next N clocks, at the outputs of the controlled inverters 8, a third system of discrete orthogonal signals, different from previous systems of functions, will be formed.

After its formation, the state of the bits of the shift register 7 will change, and a sequence of the form “00000011” will be written in it (for the case N = 8). Over the next N clocks, the outputs of the controlled inverters 8 will generate a fourth, different from previous function systems, discrete orthogonal signal system, and so on.

Let us explain in more detail the process of formation of these 2 ^N systems of discrete orthogonal signals.

Figure 4 presents the timing diagrams of the system of Walsh functions (for the case N = 8). The Walsh functions at the information outputs of the N-position switch 2 are ordered by the number of alternating signs.

5 is a timing diagram illustrating the process of generating a signal S (6, θ) of another derivative of a system of discrete orthogonal signals. The total number of discrete orthogonal signal systems that will be generated by the acoustic downhole emitter for the case N = 8 will be 2 ^N = 256. Let the sequence number of the considered system S (i, θ) be 128.

In this case, the acoustic downhole emitter has already generated 127 (given that the sequence number of the Walsh function system is the first) of various discrete orthogonal function systems, and in the N-bit binary counter 6, the number 127 is written in binary code, that is, a sequence of the form “01111111 ".

In general, during the operation of an acoustic downhole emitter, the status of the bits of the shift register 7 is determined as follows.

The Walsh function with the largest number of alternating sign (Fig. 5a) from the last output of the N-position switch 2 (for example, for the case N = 8 it will be the Wal (7, θ) function) is input to the null-organ 4, which forms at its output the pulse at the time of changing the signal at its input from “+” to “-” or from “-” to “+” (fig.5b). The pulses from the output of the null-body 4 are fed to the shifting input of the N-bit shift register 7, at the output of the highest bit of which control pulses are formed, which arrive at the control inputs of the controlled inverters 8.

The pulses from the output of the null-organ 4 also go to the input of the frequency divider 5 with a division coefficient N, therefore, every N clock cycles of the emitter, a pulse is generated at the output of the frequency divider 5, which, firstly, increases by one the value of the binary number written in N -bit binary counter 6, and secondly, by entering the input of the N-bit shift register 7, it is possible to write this binary number from the bits of the N-bit binary counter 6 to the corresponding bits of the N-bit shift register 7.

So, in the case under consideration, the number 127 is written in binary code in the N-bit binary counter 6, that is, a sequence of the form “01111111”, which is written into the bits of the N-bit shift register 7 and appears at the output of its highest bit (Fig. 5c) synchronously with the formation of Walsh functions at the information outputs of the N-position switch 2.

The sequence "01111111" will go to the control inputs of the controlled inverters 8, to the information inputs of which the Walsh functions Wal (i, θ) are received.

Managed inverters 8 are arranged so that when they enter their control input "0" at the output of the controlled inverter, a signal is generated that goes to its information input, and when they arrive at their control input "1", an invert operation is performed, and a signal is generated at the output of the controlled inverter entering its information input, but in an inverted form.

Thus, for example, the Walsh function Wal (6, θ) (Fig. 5, d) supplied to the input of the seventh controlled inverter 8 will be converted, and the signal S will be generated at the output of the seventh controlled inverter 8 (Fig. 5d), θ).

Figure 5 shows the timing diagrams illustrating the process of generating the signal S (6, θ) in the proposed device.

The diagrams show the temporary state:

a) the last output of the N-position switch 2, on which the function Wal (7, θ) is generated;

b) the output of the null organ 4;

C) the output of the high order of the N-bit register 7 shift;

d) the seventh output of the N-position switch 2, on which the function Wal (6, θ) is formed;

d) the output of the seventh controlled inverter 8, on which the signal S (6, θ) is generated.

Figure 6 presents the timing diagrams of the considered 128th system of discrete orthogonal signals S (i, θ).

The orthogonality of the functions S (i, θ) formed in the proposed device can be verified by multiplying any functions of the system S (i, θ) and integrating the result of the multiplication over time T (where T is the period of definition of the functions). Orthogonality is also possessed by all 256 formed systems of discrete orthogonal signals (for the case N = 8).

So, the number of generated systems of discrete orthogonal signals in the general case is equal to 2 ^N.

The presence of new elements (zero-organ 4, frequency divider 5 with a division coefficient N, N-bit binary counter 6, N-bit shift register 7 and N controlled inverters 8) in the proposed device, used together with N-position switch 2 and amplifier 3 power with a balanced output, allows you to implement 2 ^N systems of discrete orthogonal signals, each of which includes N laws of phase manipulation of sound pressure in (N + 1) translucent gaps on the surface of a rigid sealed cylindrical body, that is to form 2 ^N systems from N different (non-repeating) laws of phase manipulation of sound pressure.

In this case, N × 2 ^{N of} various types of directivity characteristics in the vertical plane will be obtained, which will dramatically increase the irradiated volume of the working medium, thereby increasing the efficiency of the influence of powerful sound on the controlled volume of the working medium. As the laws of phase manipulation, we used distributions realized not only by Walsh functions, but also by all other possible systems of discrete orthogonal signals with samples “+1” and “-1”, that is, their combination really forms a complete set.

In this case, more complex directivity characteristics are formed than in the prototype, which together form a fan of directivity characteristics in the vertical plane, which really evenly covers the entire irradiated volume of the working medium without increasing the emitted acoustic power.

When applying to the part 1 of the proposed acoustic borehole emitter of electric sound frequency of the sound frequency of the piezoelectric packet 9 (FIG. 2), the volume of the electrical insulating liquid located between the ends of the adjacent modules is mechanically excited and acoustic energy is emitted through the soundproof windows 15 (FIG. 3) Wednesday

When using the proposed acoustic borehole emitter, a fan of rays is formed, which really sounds the entire volume of the working medium without increasing the radiated acoustic power.

Powerful acoustic oscillations generated by the emitter affect the surrounding soil of the bottom-hole layer of the oil or gas reservoir, significantly (up to 60%) improving its productive properties. With a large thickness of the formation, acoustic processing is performed at one level of immersion of the part of the proposed acoustic downhole emitter lowered into the well, but when all possible 2 ^N systems are formed from N different (non-repeating) laws of phase manipulation of sound pressure.

Thus, the proposed acoustic downhole emitter has enhanced functionality due to the use of 2 ^N systems from N different (non-repeating) laws of phase manipulation of sound pressure, which leads to an increase in the efficiency of acoustic exposure and an increase in the voiced volume of the working medium without increasing the radiation power.

Claims (1)

An acoustic borehole emitter containing active modules in the form of piezoelectric packs with end plates tightened by central pins, placed along the axis of a rigid sealed cylindrical body filled with electrical insulating fluid and translucent at least in the region of the spaces between the modules, spring elements that mechanically fasten the ends together adjacent modules and ends of end modules with end caps of the housing, while the flexibility of each spring element is more than an order of magnitude greater the flexibility of the volume of the insulating liquid in the gap between the active modules, and the power source electrically connected to the emitter, N by the number of piezoelectric packs of acoustically soft cylindrical screens placed between the side surface of the piezoelectric packs and the inner surface of the rigid sealed cylindrical body, the end plates are made frequency-reducing so that effective the speed of sound, which determines the frequency of longitudinal resonance in piezoelectric packets with end plates, is (1.2-1.3) C, where C is the speed of sound in an external working environment, the distance between the end plates of adjacent modules and the ends of the end modules and the end caps of the housing is (0.2-0.25) λ, where λ is the wavelength of acoustic radiation in the external working environment, the power source is connected to the emitter by means of a power amplifier, which is made with a symmetric output and equipped with an N-position switch, the second symmetric output of the power amplifier is connected to a symmetric second input of the N-position switch, and the distance between the centers (N + 1) of sound koprozrachnyh intervals rigid hermetic cylindrical body still (0,8-0,85) λ, characterized in that, in order to increase functionality by using 2 ^N N systems of different (non-recurring) laws DPSK sound pressure, leading to increased efficiency acoustic exposure and increasing the voiced volume of the working medium without increasing the radiation power, a zero-organ, a frequency divider with a division coefficient N, an N-bit binary counter, N-bit register are introduced into it shift and N controlled inverters, with the N outputs of the switch connected to the information inputs of the corresponding controlled inverters, the outputs of which are connected to the electrical inputs of the corresponding piezoelectric packets, the last output of the N-position switch (the Walsh functions at the outputs of the switch are ordered by the number of alternating sign) connected to the input of the zero-organ the output of which is connected to the shifting input of the N-bit shift register and the input of the frequency divider with a division coefficient N, the output of the frequency divider with a division coefficient N is connected to the control input of the N-bit shift register entry and the counting input of the N-bit binary counter, the information outputs of the N-bit binary counter bits are connected to the corresponding information inputs of the N-bit shift register, the output of the highest bit of the N-bit shift register is connected to the control inputs of all controlled inverters.

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