Method for calculating annulus sound velocity and annulus liquid level based on electromagnetic sound wave

Abstract

The application discloses a kind of annular space sound velocity and annular space liquid level calculation method based on electromagnetic acoustic wave, comprising: through electromagnetic acoustic wave transmitter, frequency-modulated acoustic wave is emitted to annular space, and through the frequency-modulated acoustic wave of emission, coupling echo is obtained, and the annular space sound velocity is calculated by the time difference of coupling wave and the spacing between couplings;When liquid level is low and cannot be used to judge annular space sound velocity by coupling wave, then the temperature collected by temperature sensor is used to calculate the annular space sound velocity.The present application has high measurement accuracy and small error.

Description

TECHNICAL FIELD

[0001] The application relates to a pressure-controlled drilling heavy-slug cap tripping annulus sound velocity and annulus liquid level calculation method and belongs to the technical field of drilling engineering. BACKGROUND

[0002] Sound wave propagation in the annulus is mainly affected by temperature, pressure and the medium itself. When the liquid level is shallow from the wellhead, the sound velocity can be calculated by measuring the temperature at the wellhead. When the liquid level is far from the wellhead, the temperature in the well is affected by the geothermal temperature and has a certain difference with the temperature at the wellhead. The temperature in the well is generally difficult to accurately measure. The annulus sound velocity can be calculated by the time difference of the coupling wave and the coupling interval. However, the sound wave frequency is too low when the gas gun method is used for distance measurement, the coupling echo is not obvious, and it is difficult to calculate the sound velocity by the coupling wave.

[0003] In addition, an annulus liquid level testing method based on a pressure wave signal source is disclosed in Well Logging Technology in October 2019. The method applies pressure to the annulus in the form of static pressure disturbance. The method cannot be frequency-adjusted, cannot accurately obtain the coupling wave to calculate the annulus sound velocity, and has a large error in the calculation of the annulus liquid level position. SUMMARY

[0004] The application aims to overcome the above problems in the prior art and provide an annulus sound velocity and annulus liquid level calculation method based on an electromagnetic sound wave. The application has high measurement accuracy and small error.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0006] An annulus sound velocity and annulus liquid level calculation method based on an electromagnetic sound wave, characterized in that a frequency-modulated sound wave is emitted to the annulus by an electromagnetic sound wave emitter, a coupling echo is obtained through the emitted frequency-modulated sound wave, and the annulus sound velocity is calculated through the time difference of the coupling wave and the coupling interval. When the liquid level is low and the coupling wave cannot be used to judge the annulus sound velocity, the temperature collected by a temperature sensor is used to calculate the annulus sound velocity.

[0007] The method comprises the following steps:

[0008] a. Emitting a modulated sound wave and collecting an echo signal: emitting a modulated sound wave to the annulus and collecting coupling echo and liquid level echo data to obtain a sampling signal;

[0009] b. Filtering processing: obtaining a filtered signal through filtering processing of the sampling signal;

[0010] c. Sectional processing: dividing the filtered signal into two sections, the first section being a transmission section signal and the second section being a receiving section signal;

[0011] d, collar wave and liquid surface echo detection: the received segment signal is detected with the transmitted segment signal to obtain a maximum point, and the maximum point is recorded as a liquid surface echo point;

[0012] e, judging whether the maximum point in step d is greater than 3, if the maximum point is greater than 3, the annulus sound velocity is calculated by using the collar wave, if the maximum point is less than 3, the collar wave is enhanced by increasing the frequency of the modulated sound wave until the maximum point is greater than 3, and then the annulus sound velocity is calculated by using the collar wave, and finally the annulus liquid surface position is obtained by the obtained annulus sound velocity.

[0013] In step a, the modulated sound wave with high frequency and low loudness is transmitted when the managed pressure drilling fluid surface is not at the wellhead or during detection, the modulated frequency of the modulated sound wave is f, 20Hz≤f≤1500Hz, the sound emission time is T0, 0.01s≤T0≤0.1s, and the loudness is A% (0≤A≤100).

[0014] The modulated sound wave is amplified to 500-2000W by the pre-power amplifier and the post-power amplifier and then transmitted by the electromagnetic sound wave transmitter.

[0015] The sound wave is transmitted axially along the annulus, a part of the sound wave is reflected upward to form a collar echo when passing through the drill collar, and the other part of the sound wave continues to be transmitted downward and is reflected upward to form a liquid surface echo when encountering the liquid surface.

[0016] The data collection is defined as a starting point T1 when the sound wave sensor starts collecting data, the sound wave sensor samples at a sampling frequency fs, the sampling time is T, 5s≤T≤10s, and the sampling signal is s(i).

[0017] In step b, a band-pass filter based on the Kaiser window function is selected, the minimum frequency of the filter is fmin=0.7f, the maximum frequency is fmax=2f, and the sampling signal s(i) is filtered through the band-pass filter to obtain the filtered signal sn(i).

[0018] In step c, the filtered signal sn(i) is divided into two segments, the first segment is the transmission segment, the time is T1-T1+T0, the transmission segment signal is M(t), and the second segment is the receiving segment, the time is T1+T0-T-T1-T0, and the receiving segment signal is s(t).

[0019] In step d, the receiving segment signal s(t) is detected with the transmission segment signal M(t) by using the following formula:

[0020]

[0021] The maximum point of R(τ) is obtained, which is R'(t1), R'(t2)...R'(t n), these maximum points are recorded as liquid surface echo points, and the maximum point is recorded as liquid surface echo point R'max(t0), and the liquid surface echo time is t0+T0.

[0022] In step e, if the maximum point in step d is greater than 3, the formula is used to determine the annulus sound velocity, where L is the distance between two adjacent collars, t n is the time of the nth collar wave, t n-1 is the time of the n-1 collar wave; the annulus liquid surface position L0=C n ×(t0+T0) / 2.

[0023] In step e, when the liquid surface is low and cannot be used to determine the annulus sound velocity, the collected annulus temperature tem is used to calculate the annulus sound velocity, and the annulus sound velocity C n =331.45+0.61tem.

[0024] The advantages of the present application are:

[0025] 1. The traditional explosive sound generation method cannot adjust the frequency and loudness, and the electromagnetic sound wave transmitter is used as the sound source in the present application, and the frequency and loudness of the emitted sound wave can be adjusted, which can effectively improve the recognition effect of the shallow liquid surface.

[0026] 2. The present application can accurately filter according to the frequency of the emitted sound wave, and weaken the noise interference; the correlation detection used can improve the recognition rate of the collar echo and the liquid surface echo.

[0027] 3. The annulus sound velocity is mainly affected by the annulus temperature, and as the well depth increases, the annulus temperature is generally difficult to measure. Different annulus sound velocity calculation methods are adopted for different echo conditions in the present application. When the annulus liquid surface is shallow, the temperature sensor is used to monitor the annulus temperature in real time to calculate the annulus sound velocity. For the case where the annulus liquid surface is deep, the time difference between two collar waves is used to calculate the annulus sound velocity. This method can effectively reduce the influence of temperature on sound velocity calculation, and the annulus liquid surface measurement error is small. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the collar wave corresponding to different frequencies in the present application;

[0029] Figure 2 is a detection echo diagram under the condition of a shallow liquid surface using a gas gun method;

[0030] Figure 3 is a 300Hz echo time-domain diagram of the electromagnetic sound wave transmitter under the condition of a shallow liquid surface;

[0031] Figure 4 is a 300Hz correlation detection diagram under the condition of a shallow liquid surface;

[0032] Figure 5 Time-domain graph of 300Hz echo for deep liquid surface case;

[0033] Figure 6a Time-domain graph of 300Hz collar wave R'(t n-1 ) echo for deep liquid surface case;

[0034] Figure 6b Time-domain graph of 300Hz collar wave R'(t n ) echo for deep liquid surface case;

[0035] Figure 6c Time-domain graph of 300Hz liquid surface echo R'max for deep liquid surface case;

[0036] Figure 7 Schematic diagram of device involved in application of the method. DETAILED DESCRIPTION

[0037] Example 1

[0038] The present application provides the following method to determine the annulus sound velocity, transmit the frequency-modulated sound wave by the electromagnetic sound wave transmitter to obtain clear collar echo, calculate the annulus sound velocity by the time difference of collar wave and the collar spacing, and when the liquid surface is low and the annulus sound velocity cannot be judged by the collar wave, calculate the annulus sound velocity by the temperature collected by the temperature sensor.

[0039] The specific implementation steps are as follows:

[0040] The first step is to transmit the modulated sound wave and collect the echo signal: when the control pressure drilling fluid surface is not at the wellhead or the detection instruction is received, open the electromagnetic valve, modulate the high-frequency low-loudness modulated sound wave by the central processor, the modulation frequency is f (20≤f≤1500), the sound emission time is T0 (0.01s≤T0≤0.1s), and the loudness is A% (0≤A≤100). The modulated sound wave is amplified by 500-2000W by the pre-power amplifier and the post-power amplifier, and then is transmitted by the electromagnetic sound wave transmitter. The sound wave is transmitted downward along the axis in the annulus, a part of which is reflected upward when passing through the drill collar, forming a collar echo, and the other part of the sound wave continues to transmit downward, and is reflected upward when encountering the liquid surface, forming a liquid surface echo. The sound wave sensor is responsible for collecting the echo data. When the central processor issues the detection sound wave instruction, the sound wave sensor starts to collect the data, and this time is defined as the starting point T1. The data collector samples at the sampling frequency fs, and the sampling time is T (5s≤T≤10s). The sampling signal is s(i).

[0041] The second step is filtering processing: select the band-pass filter based on the Kaiser window function, the minimum frequency of the filter is fmin=0.7f, and the maximum frequency is fmax=2f. The sampling signal s(i) is passed through the band-pass filter to obtain the filtered signal sn(i).

[0042] Third step: segment processing: the filtered signal sn(i) is divided into two segments, the first segment is the transmission segment, the time is: T1~T1+T0, the transmission segment signal is M(t), the second segment is the receiving segment, the time is: T1+T0~T-T1-T0, the receiving segment signal is s(t).

[0043] Fourth step: detection of collar wave and liquid surface echo: the receiving segment signal s(t) is correlated with the transmission segment signal M(t), and the formula is used:

[0044]

[0045] The maximum points of R(τ) are R'(t1), R'(t2)...R'(t n ), which are called echo points. The maximum point of the maximum value is called the liquid surface echo point R'max(t0), and the liquid surface echo time is t0+T0.

[0046] Fifth step: determine whether the maximum value point obtained in the fourth step is greater than 3, if it is greater than 3, the formula can be used to determine the annulus sound speed, where L is the distance between two adjacent collars, t n is the time of the nth collar wave, t n-1 is the time of the (n-1)th collar wave.

[0047] If the maximum value point is less than 3, it means that the collar wave is not obvious, and the incident wave frequency can be increased to enhance the collar wave until the maximum value point obtained is greater than 3.

[0048] In the fifth step, when the liquid surface is low and cannot be used to determine the annulus sound speed, the annulus sound speed calculation and the liquid surface position determination are used to calculate the sound speed C n = 331.45+0.61tem using the temperature tem collected by the temperature sensor.

[0049] For example: the temperature collected by the temperature sensor is 10℃, then the sound speed is:

[0050] C n (10℃) = 331.45+0.61*10 ≈ 338 m / s

[0051] Then the annulus liquid surface position is calculated using the calculated annulus sound speed:

[0052] If the maximum value point obtained in the fourth step is greater than 3, as shown in Figure 1 , the collar echo corresponding to the high-frequency detection sound wave is stronger than the collar echo corresponding to the low-frequency detection sound wave, and the sound speed can be calculated using the collar wave, and the distance between the drill pipe collars is L, then the sound speed C n = L / (t n -t(n-1) The position of the annular liquid level is L0 = C. n ×(t0+T0) / 2.

[0053] Example 2

[0054] This embodiment describes the specific application of the method of the present invention in conjunction with the accompanying drawings.

[0055] When the liquid surface is shallow, the sound wave frequency is too low and the loudness is too high when using the air gun method for distance measurement. The sound wave oscillates continuously in the annulus, resulting in unclear echoes from the coupling and the liquid surface. Figure 2 As shown, it is therefore difficult to calculate the speed of sound and the distance to the annular liquid surface using the coupling wave.

[0056] When the liquid level is shallow, an electromagnetic sound wave transmitter emits a modulated sound wave. The solenoid valve is opened, and the central processing unit modulates a high-frequency, low-loudness sound wave. The modulation frequency is f = 300 Hz, the emission time is T0 = 0.05 s, and the loudness is 100%. The echo from the liquid surface is as follows: Figure 3 As shown.

[0057] Depend on Figure 3 It can be seen that using an electromagnetic sound wave transmitter to emit detection sound waves with frequency, loudness, and time modulation can make the liquid surface echo clearly visible.

[0058] Depend on Figure 4 Correlation analysis revealed that the coupling echo was weak, making it difficult to determine the annular sound velocity from the coupling wave. At this point, the temperature sensor recorded 20℃. Therefore, using the formula: C... n (20℃)=331.45+0.61*20≈343m / s Calculate the annular sound velocity. The liquid surface echo time is t0+T0=0.1869s. Then the position of the liquid surface in the annulus is L0=343*0.1869 / 2=32m.

[0059] When the liquid level is deep, an electromagnetic sound wave transmitter emits a modulated sound wave. The solenoid valve is opened, and the central processing unit modulates a high-frequency, low-loudness sound wave. The modulation frequency is f = 300 Hz, the emission time is T0 = 0.05 s, and the loudness is 100%. The echo from the liquid surface is as follows: Figure 5 As shown.

[0060] After filtering and segmentation, correlation detection is performed. The correlation detection graph is shown in Figure 6, where Figure 6(a) shows the coupling wave R'(t). n-1 ), coupling wave time t n-1 =0.2788, Figure 6(b) shows the coupling wave R'(t) n ), coupling wave time t n =0.3074, Figure 6(c) shows the liquid surface echo time point, the liquid surface echo time is 0.9164. Given that the spacing between the couplings is 9.68m, the annular sound velocity is... The position of the annular liquid level is: L0 = C n ×(t0+T0) / 2=338.64×0.9164 / 2=155.08m.

[0061] Example 3

[0062] This embodiment describes the apparatus involved in the method of the present invention.

[0063] The apparatus involved in the method of the present invention includes a central processing unit, a preamplifier, a postamplifier, an electromagnetic acoustic wave transmitter, an acoustic wave sensor, a temperature sensor, a solenoid valve, a data acquisition unit, and a filter.

[0064] like Figure 7 As shown in the figure, the markings are: 1-wellbore, 2-drill pipe, 3-annulus, 4-coupling, 5-fluid level, 6-solenoid valve, 7-acoustic sensor, 8-temperature sensor, 9-electromagnetic acoustic transmitter, 10-data acquisition unit, 11-filter, 12-power amplifier, 13-power amplifier, 14-central processing unit, 15-logging data.

[0065] The central processing unit modulates the sound waves, analyzes the echoes, controls the solenoid valves, and calculates the position of the annular fluid level. The emitted sound waves can automatically select the optimal frequency and loudness based on the well structure and fluid depth.

[0066] A preamplifier can amplify the voltage of the modulated audio signal output by the central processing unit, improve the system's signal-to-noise ratio, reduce external interference, and achieve impedance conversion and matching.

[0067] The post-amplifier is responsible for amplifying the audio signal current output from the pre-amplifier, enabling the electromagnetic sound wave transmitter to function properly.

[0068] The electromagnetic sound wave transmitter is responsible for emitting the audio signal output by the post-power amplifier. Its features include adjustable frequency and loudness, with a frequency range of 200 to 1500 Hz and a loudness range of 70 to 130 dB.

[0069] The acoustic wave sensor is responsible for collecting the emitted and echo signals in the channel. The acoustic wave sensor and the electromagnetic acoustic wave transmitter are in the same channel. There can be one or more of them, and their sensitivities are different. A single acoustic wave transmitter is sensitive to acoustic wave signals within a specific frequency range.

[0070] The temperature sensor is responsible for collecting the temperature in the channel where the audio sensor is located, for the purpose of calculating the speed of sound. It is in the same channel as the sound wave sensor and the electromagnetic sound wave transmitter.

[0071] The electromagnetic valve is responsible for opening or closing the channel connected with the annulus of the electromagnetic acoustic transmitter, and can be automatically opened or closed according to the monitoring task, has certain pressure bearing capacity, and can block the mud from entering the channel where the electromagnetic acoustic transmitter is located.

[0072] The data collector is responsible for collecting the signals of the electromagnetic valve, the temperature sensor and the acoustic sensor. The filter is responsible for filtering the acoustic signals collected by the data collector, can filter out the signals outside the frequency range of the electromagnetic acoustic transmitter, can reduce the noise signals, and can improve the signal-to-noise ratio.

Claims

1. A method for calculating annular sound velocity and annular liquid level based on electromagnetic acoustic waves, characterized in that: The method comprises the following steps: The method comprises the following steps: a. transmitting modulated sound waves and collecting echo signals: transmitting modulated sound waves to the annulus and collecting collar echo and liquid surface echo data to obtain sampling signals; b. filtering processing: obtaining filtered signals after filtering processing of the sampling signals; c. segment processing: dividing the filtered signals into two segments, the first segment being a transmission segment signal and the second segment being a receiving segment signal; d. collar wave and liquid surface echo detection: detecting the receiving segment signal and the transmission segment signal to obtain a maximum value point, which is recorded as a liquid surface echo point; e. judging whether the maximum value point in step d is greater than 3, if the maximum value point is greater than 3, calculating the annulus sound velocity by using the collar wave, if the maximum value point is less than 3, increasing the frequency of the modulated sound waves to enhance the collar wave until the maximum value point is greater than 3, and then calculating the annulus sound velocity by using the collar wave; finally, obtaining the annulus liquid surface position through the obtained annulus sound velocity; In step c, the filtered signal sn(i) is divided into two segments, the first segment being a transmission segment with a time of T1~T1+T0 and the transmission segment signal being M(t), and the second segment being a receiving segment with a time of T1+T0~T-T1-T0 and the receiving segment signal being s(t); In step d, the receiving segment signal s(t) and the transmission segment signal M(t) are detected by using the following formula: To maxima, respectively, , ... These maxima are referred to as liquid surface echo points, and the maximum maxima is referred to as the liquid surface echo point The liquid surface echo time is ; In step e, if the maximum point in step d is greater than 3, the formula determining the annulus sound velocity, where L is the distance between two adjacent collars, is the time of the n-th collar wave, is the time of the n-1-th collar wave; annulus liquid level position .

2. The electromagnetic acoustic wave based annular velocity and annular level calculation method of claim 1, wherein: In step a, when the control pressure drilling fluid surface is not at the wellhead or during detection, modulated sound waves with high frequency and low loudness are modulated, the modulation frequency of the modulated sound waves is f, 20Hz≤f≤1500Hz, the sound emission time is T0, 0.01s≤T0≤0.1s, and the loudness is A%, 0≤A≤100.

3. The electromagnetic acoustic wave based annular velocity and annular level calculation method of claim 2, wherein: The modulated sound waves are amplified to 500~2000W by a pre-power amplifier and a post-power amplifier and then emitted by an electromagnetic sound wave emitter; the sound waves are transmitted axially downward along the annulus, a part of the sound waves is reflected upward when passing through the drill collar to form a collar echo, and the other part of the sound waves continues to be transmitted downward and is reflected upward when encountering the liquid surface to form a liquid surface echo.

4. The electromagnetic acoustic wave based annular velocity and annular level calculation method of claim 3, wherein: In the data collection, the start point T1 is defined when the sound wave sensor starts collecting data, the sound wave sensor samples at a sampling frequency fs, the sampling time is T, 5s≤T≤10s, and the sampling signal is s(i).

5. The electromagnetic acoustic wave based method of annular velocity and annular level calculation of claim 4, wherein: In step b, a band-pass filter based on the Kaiser window function is selected, the minimum frequency of the filter is fmin=0.7f, the maximum frequency is fmax=2f, and the sampling signal s(i) is filtered by the band-pass filter to obtain the filtered signal sn(i).

6. The electromagnetic acoustic wave based annular velocity and annular level calculation method of claim 5, wherein: In step e, when the liquid level is low and the collar wave cannot be used to determine the annulus sound velocity, the collected annulus temperature tem is used to calculate the annulus sound velocity, and the annulus sound velocity = 331.45 + 0.61 .

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