CN103775067A - Directional sound wave logging while drilling device - Google Patents

Abstract

A directional sound wave logging while drilling device comprises a drill collar special for the directional sound wave logging while drilling device and a directional sound wave while drilling sonic system installed on a drill collar upper centralizer and composed of a single-transmitting four-receiving probe, and adopts a groovy sound insulator on the drill collar to inhibit drill collar direct waves from a transmitting probe to a receiving probe, wherein the transmitting probe and the receiving probe are respectively powered on by a special power supply battery. A measurement and control circuit receives acquired waveform data to perform real-time calculation treatment, communication interfaces are provided for a measurement while drilling system (MWD) and a ground processing system, the power supply battery and the measurement and control circuit are arranged in a compression resistance barrel in a special drill collar mud flowing channel special for sound waves, and upper and lower flow guiding sleeves are connected with the sonic system. The stratum rock longitudinal and transverse sound velocity measured in the drilling process in real time can be used for lithological identification, porosity degree calculation, rock mechanical parameters, well opening stability prediction and the like.

Description

Azimuth acoustic logging device while drilling

technical field

The invention relates to an azimuth acoustic logging device while drilling in the field of logging devices.

Background technique

In recent years, acoustic logging technology has been successfully applied in the process of drilling while drilling. Acoustic logging while drilling uses the sliding wave measurement method to measure the changes in the sound velocity of longitudinal and shear waves in the formation rock in real time. By measuring the longitudinal and shear wave velocities of the formation, it can not only provide formation porosity, improve drilling safety factor through real-time formation pressure prediction, and pass and seismic data Combined with reducing the risk of geophysical exploration and improving the efficiency of geosteering, it can also analyze rock mechanical properties and predict drilling accidents. The sonic logging while drilling completes the sonic logging operation while drilling, which reduces the time occupied by the drilling rig at the well site and saves costs from the integrated drilling-logging service. For highly deviated wells, horizontal wells or drilling in special geological environments, wireline logging is difficult or risky, so that operations cannot be performed, sonic logging while drilling can be replaced. Therefore, this technology is of great significance in drilling engineering and oil and gas exploration.

However, due to the particularity of its working environment while drilling, the realization of acoustic logging while drilling is much more complicated than that of wireline logging. In order to succeed in acoustic logging while drilling, there are four technical problems that must be solved, mainly: acoustic probe and installation process; suppression of drill collar direct wave between the transmitting probe and the receiving probe; suppression of drilling noise interference and downhole waveform Real-time processing, extracting the time difference and sending it to the ground.

At present, domestic sonic logging while drilling technology mainly involves acoustic transducers or drill collar sound insulators, among which CN 102162358 A relates to a combination of sonic logging while drilling transducers. Piezoelectric ceramic discs. CN 102322258 A adopts the principle and method of widening the inherent stop band of the drill collar tensile wave to solve the problem of the direct wave of the drill collar, which can avoid the adverse effect of grooves on the strength of the drill collar. However, whether it is a transducer or a drill collar sound insulator, it will be affected by different conditions when realizing the measurement function, and one aspect cannot be considered separately, otherwise the measurement will be incorrect.

Contents of the invention

The object of the present invention is to solve the problems existing in the prior art, and provide a kind of azimuth acoustic logging device while drilling, which constitutes the acoustic system while drilling through the single-shot and four-receive probes installed on the drill collar, and adopts directional emission and reception technology, through The downhole measurement and control circuit processes the downhole waveform in real time, extracts the time difference and sends it to the ground. In addition, the sound insulator with grooves on the drill collar is used to suppress the direct wave of the drill collar between the transmitting probe and the receiving probe. The real-time measured sound velocity of compressional and shear waves in formation rocks during the drilling process can be used for lithology identification, porosity calculation, rock mechanical parameters calculation, wellbore stability prediction, etc.

The azimuth acoustic logging device while drilling of the present invention comprises:

Special drill collar, sound system and measurement and control circuit, wherein the measurement and control circuit includes sound wave excitation circuit, signal receiving and processing circuit, control and data processing circuit, power supply circuit. Between the upper and lower centralizers, there is a sound insulation body composed of periodically staggered sound guide grooves; the sound system uses 1 transmitting probe and 4 receiving probes to form a receiving probe array, and the transmitting probes are arranged in the drill In the groove of the lower centralizer of the drill collar, the receiving probe array 9 is arranged axially in the groove of the upper centralizer of the drill collar, and the acoustic system communicates with the external MWD and the special drill collar through the upper and lower diversion sleeves respectively. The power supply battery, measurement and control circuit connection.

The sound guide grooves that make up the sound insulation body are set to 4; the receiving and emitting probes are designed and manufactured by modularization, that is, the piezoelectric vibrator is fixed on a base with a shock-absorbing structure, and the sound-transmitting window is covered for packaging. Silicone oil is injected to form a probe; the diversion sleeve and the drill collar opening are strictly concentric, and the internal and external connections are made through a high-pressure sealing plug; the power supply battery and the measurement and control circuit are respectively installed in a special pressure-resistant cylinder, and the special pressure-resistant cylinder is placed in the center of the special drill collar. In the mud flow channel, the rubber centralizer with the same inner diameter as the drill collar is connected to the inner wall of the drill collar.

The receiving and transmitting probes are arranged in a radially stacked multi-layer piezoelectric vibrator. The piezoelectric vibrator and the base are bonded together with high-temperature adhesive. The sound-transmitting window is made of fluororubber, silicone rubber or other insulating materials. Grinding through the sound window; installing a sound-insulating rubber pad between the base 16 and the drill collar.

The groove widths of the sound guide grooves are: 130mm, 110mm, 90mm, and 110mm, and the depth is 14mm. The intervals of the sound guide grooves are: 110mm, 90mm, and 110mm.

The excitation circuit of the measurement and control circuit generates the excitation signal of the emission sound system under the action of the ignition pulse from the control and data processing circuit. The working frequency range is 12 ~ 18kHz, and the width of the excitation pulse is adjustable; The same independent channel amplifies, filters and collects different channel signals from each probe in the receiving sound system. The bandwidth of the four-channel analog program-controlled amplifier is 10-20KHz, and the four-channel 14-bit waveform data acquisition; the control and data processing system is based on DSP With CPLD chip as the core, the control system generates all the control sequences required for the system work after receiving the control commands from the measurement while drilling system MWD. Data transmission among them, including channel gain, acquisition depth, acquisition rate, sending launch pulse, acquisition start command, and real-time calculation, processing and storage of received and acquired waveform data; power supply circuit is 24-36VDC battery, power supply The MPU in the circuit controls the switch of the power supply circuit to realize the intermittent working mode according to the instructions of the MWD system.

The storage of control and data processing system uses large-capacity non-volatile FLASH memory to store logging data.

The memory adopts NAND FLASH chip as non-volatile data storage.

The present invention has the advantages of not only considering the design of the transducer and the matching of the drill collar, but also considering the circuit realization of the basic measurement of the acoustic logging while drilling, and reducing the influencing factors of the acoustic logging while drilling as much as possible through overall consideration. Obtain the correct sound velocity of compressional and transverse waves in formation rocks. In addition, through the directional emission and reception technology, combined with the azimuth judgment function, the azimuth acoustic logging is realized.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 Schematic diagram of azimuth acoustic logging device while drilling

Figure 2a The enlarged schematic diagram of the part of the emission probe from A-A in Figure 1

Figure 2b The enlarged schematic diagram of the receiving probe array in Figure 1

Figure 3 The enlarged schematic diagram of the sound insulation body in Figure 1

Fig. 4 Schematic diagram of the measurement and control circuit of the acoustic azimuth wave logging device while drilling

In the figure: 1 special drill collar, 2 sound insulation body, 3 measurement and control circuit, 4 power supply battery, 5 lower diversion sleeve, 6 upper diversion sleeve, 7 upper centralizer, 8 lower centralizer, 9 receiving probe array, 10 transmitting Probe, 11 Acoustic channel A, 12 Acoustic channel B, 13 Acoustic channel C, 14 Acoustic channel D, 15 Piezoelectric vibrator, 16 Base, 17 Acoustic window.       

Detailed ways

As shown in Fig. 1, the azimuth acoustic logging device while drilling includes: special drill collar 1, acoustic system (transmitting probe 10, receiving probe array 9), measurement and control circuit 3, power supply battery 4 and upper and lower diversion sleeves 5, 6. The special drill collar 1 is a non-magnetic drill collar with an outer diameter of 178mm. The center of the special drill collar 1 is a mud flow channel. In order to install the acoustic system, centralizers 7 and 8 are designed during the processing of the special drill collar 1 to ensure sufficient The sound system is installed at the position, and the sound system is placed through the slot on the side wall of the centralizer. The sound system communicates with the upper end measurement while drilling system MWD (Measurement While Drilling) through the upper and lower guide sleeves 5 and 6 respectively, and communicates with the power supply battery 4 and the measurement and control circuit. 3 Connection, the diversion sleeve and the drill collar opening are strictly concentric, and the internal and external connections are made through high-pressure sealing plugs. The power supply battery 4 and the measurement and control circuit 3 are respectively installed in a special anti-pressure cylinder, which is centrally placed in the mud flow channel of the special drill collar 1, and connected to the inner wall of the drill collar through a rubber centralizer with the same inner diameter as the drill collar. Between the upper centralizer 7 and the lower centralizer 8 is a sound insulator 2 . The entire measurement system is located in the borehole, which is filled with mud.

The sound system of the azimuth acoustic logging device while drilling adopts the single-shot and four-receive mode, including one transmitting probe 10, and four receiving probes to form the receiving probe array 9, and the transmitting probe 10 is arranged in the groove of the lower centralizer 8 of the drill collar , the receiving probe array 9 is arranged axially in the groove of the upper centralizer 6 of the drill collar. The sound system communicates with the upper MWD through the upper and lower guide sleeves 5 and 6 respectively and connects with the power supply battery 4 and the measurement and control circuit 3 . Both the receiving and transmitting probes are manufactured with a modular design, consisting of a piezoelectric vibrator 15, a base 16, and a sound-transmitting window 17, that is, the piezoelectric vibrator 15 is fixed on a base 16 with a shock-absorbing structure, and the outer casing is sound-transmissive. The window 17 is encapsulated and injected with silicone oil to form a probe. The piezoelectric vibrator 15 is the core component of the acoustic logging-while-drilling acoustic wave probe. By analyzing the influence of the material and geometric dimensions of the piezoelectric vibrator 15 on the resonance frequency, the substrate material, piezoelectric ceramic type, piezoelectric vibrator length, Basic parameters of piezoelectric vibrators such as width and thickness, distance from fixed point of piezoelectric vibrator, etc. The receiving and transmitting probes adopt a multi-layer piezoelectric vibrator arrangement, and the radially stacked multi-layer piezoelectric vibrator structure improves the radiation energy of the probe to useful acoustic signals. The piezoelectric vibrator 15 is fixed on the base 16 with a shock-absorbing structure. Fully considering the integrity of the piezoelectric vibrator 15 and the installation base 16, the two parts are bonded together with high-temperature adhesive. Similarly, the base 16 and the mounting base 16 The sound insulation between the drill collars 1 is fixed with high temperature adhesive. The sound-permeable window 17 is located on the upper part of the piezoelectric vibrator 15. Since its acoustic impedance matches the acoustic impedance of the silicone oil in the probe and the mud outside the special drill collar 1, it is beneficial to the emission and reception of sound waves in the formation with less attenuation. Sound-permeable window 17 adopts wear-resistant sound-permeable window, and material is fluorine rubber, silicon rubber or other suitable insulating materials. The modular structure can not only realize the acoustic isolation from the drill collar, but also have the directional radiation of sound waves. Easy removal and interchange of probe modules as well as individual testing and functional verification of probe modules. In order to further increase the energy of the useful acoustic signal, the technology of directional emission and reception is adopted.

The sound system of the LWD acoustic logging device includes 4 receiving probes to form the receiving probe array 9. The use of multiple sets of receiving probes is because it has the characteristic of narrow receiving directivity perpendicular to its axis plane, which is beneficial to determine the spatial position of the measured formation. The receiving probe array 9 of the acoustic logging while drilling device is arranged in the groove of the upper centralizer 7 of the drill collar, and each group of receiving probes adopts a modular probe, that is, a piezoelectric vibrator 15, a base 16, and a sound-transmitting window 17 composed of probe modules. Consider the sound insulation between the probe base 16 and the drill collar, and install a sound-insulating rubber pad.

The space between the upper centralizer 7 and the lower centralizer 8 of the special drill collar 1 for acoustic logging while drilling is designed as a sound insulator 2, and the sound insulator 2 is engraved on the special drill Sound groove A (11), sound guide groove B (12), sound guide groove C (13), sound guide groove D (14), its main function is to delay the sound wave signal sent from the transmitting probe 10 through the drill collar body directly Propagates to receiving probe 9. By calculating the sound insulation of three kinds of periodic groove structure sound insulators, and simulating the logging response of acoustic logging while drilling tools installed with sound insulators in fast formations, a periodic staggered arrangement is designed. The sound insulator 2 composed of grooves has a better sound insulation effect than the sound insulator composed of circular grooves. Since the sound insulator 2 is slotted on the special drill collar 1, the strength of the drill collar body will be reduced. In order to ensure safe construction during the drilling process, the drill collar designed for the sound insulator must have a certain strength. For the slotted structure The compressive, tensile and torsional strengths are analyzed by finite element simulation to ensure that they meet the actual engineering requirements. In order to meet the requirements of both, the groove widths of the sound guide grooves 11 to 14 are: 130mm, 110mm, 90mm, 110mm respectively, and the depth is 14mm. The intervals of the sound guide grooves are respectively: 110mm, 90mm, and 110mm.

The measurement and control circuit 3 of the azimuth acoustic logging device while drilling is composed of acoustic excitation circuit, signal receiving and processing circuit, control and data processing circuit, power supply circuit and other parts. The excitation circuit generates the excitation signal of the emission sound system under the action of the ignition pulse from the control and data processing circuit. The working frequency range is 12-18kHz; the width of the excitation pulse is adjustable; the signal receiving and data acquisition circuit includes 4 independent channels with identical functions to amplify, filter and collect signals from different channels of the probes in the receiving sound system. Four-channel analog program-controlled amplifier with a bandwidth of 10-20KHz; four-channel 14-bit waveform data acquisition; the control and data processing system is the control and processing center of the instrument, which takes DSP and CPLD chips as the core, and the control system receives data from the measurement-while-drilling system MWD After the control command, all the control sequences required for the system work will be generated, and the work between the various parts in the system will be coordinated through the internal bus, and the data transmission with the MWD system will be responsible. It needs to set parameters such as channel gain, acquisition depth, acquisition rate, etc., send launch pulses, acquisition start commands, and perform real-time calculation, processing, and storage of received and collected waveform data. In well logging, limited by the transmission rate, control and data processing are quickly completed downhole. The timing control of transmission and reception of acoustic logging while drilling is complicated, and the amount of data calculation is large. In order to ensure real-time performance, it is necessary to reasonably schedule the control and data processing process and coordinate the overall work of the instrument. Due to the large amount of acoustic logging while drilling data and the limitation of real-time transmission rate, it is necessary to use a large-capacity non-volatile FLASH memory to store the logging data. According to the technical requirements of acoustic logging while drilling data, NAND FLASH chips are used as non-volatile data storage. Through the reasonable design of NAND FLASH interface circuit and storage program, the data storage function of acoustic logging while drilling is realized, with a storage capacity of 256Mb . The control and data processing system also provides communication interfaces with the measurement-while-drilling system MWD and the ground processing system. The power supply circuit is powered by a 24-36VDC battery. In order to save battery energy, the MPU in the power circuit 21 controls the switch of the power circuit to realize the intermittent working mode according to the instructions of the MWD system.

The measurement and control circuit 3 of the azimuth acoustic logging device while drilling realizes the downhole real-time processing of the acoustic logging data while drilling. A simplified STC (Slowness Time Coherence) method is designed by using multi-channel received waveform numbers to extract the longitudinal wave time difference. The time correlation method is a multi-channel signal correlation analysis method in the time domain. By selecting a reasonable time window length and slowness search range, the correlation coefficients of the wave signals sent by the same transmitting source at a certain moment received by the four receivers are obtained, and the slowness corresponding to the maximum correlation coefficient is the longitudinal wave of the formation at this depth slowness. This method is used to extract the time difference of the theoretically simulated near-source acoustic waveform, which verifies the ability of the method to extract the first wave, and realizes the fast calculation of the longitudinal wave time difference extraction. Using this method, the reliability of the program is verified by calculating the time difference of synthetic waveforms in typical soft formations and hard formations. Among them, the time difference calculated for a typical hard formation is 339.00us/m, while the actual simulated input time difference is 333.33us/m, with an error of 3.21%. Among them, the time difference calculated for a typical soft formation is 258.02us/m, while the actual simulation input time difference is 250us/m, with an error of 1.61%.

In acoustic logging while drilling, there are two main types of noise sources that affect the collected acoustic signals: one is the noise generated by the downhole drilling environment, and the other is the electronic noise generated by electronic devices. The acoustic signal polluted by noise cannot be modified in a certain frequency band, nor can it be modified in a certain moment in the time domain, because the frequency band of the noise is very wide, almost occupying the entire frequency domain, making it overlap with the acoustic signal, making it indistinguishable and useful Signal and noise, so the general noise reduction method is difficult to achieve satisfactory results. Aiming at the electronic noise in the process of acoustic logging while drilling, a noise reduction algorithm for acoustic signal data based on V system is proposed. By performing V-system transformation on the sound wave signal, then eliminating the high-frequency part, and inversely transforming it, the noise-reduced sound wave signal is obtained. The experimental results show that the algorithm has a good noise reduction effect on acoustic logging signals.

Claims (7)

1. one kind with boring orientation acoustic logging device, comprise special drill collar, sonic system and telemetry circuit, wherein telemetry circuit comprises acoustic wave excitation circuit, signal reception and treatment circuit, control and data processing circuit, power circuit, it is characterized in that: special drill collar is respectively equipped with upper centralizer and lower centralizer near upper and lower end parts, between upper and lower centralizer, be provided with the acoustic isolater of leading sound track formation that cycle staggering is arranged; Sonic system adopts 1 transmitting probe, 4 receiving transducer composition receiving transducer arrays, transmitting probe is arranged in the groove of lower centralizer of drill collar, receiving transducer array 9 is arranged in by axially-aligned in the groove of upper centralizer of drill collar, and sonic system is connected with supplying cell, telemetry circuit in outside MWD and special drill collar respectively by upper and lower flow guide sleeve.

2. according to claim 1 with boring orientation acoustic logging device, it is characterized in that: the sound track of leading that formation acoustic isolater is is made as 4; Receive and transmitting probe all adopts modularized design to make, that is: piezoelectric vibrator is fixed on a pedestal with shock-damping structure, overcoat entrant sound window, encapsulates and injects a probe of silicone oil formation; Flow guide sleeve is strictly concentric with drill collar perforate, fills in the inside and outside connection of row by high pressure sealing; Supplying cell, telemetry circuit are contained in respectively in special resistance to compression cylinder, and special resistance to compression cylinder is placed in the mud runner of special drill collar between two parties, is connected with drill collar inwall by the rubber centralizer identical with drill collar internal diameter.

3. according to claim 2 with boring orientation acoustic logging device, it is characterized in that: receive and the radially multi-layer piezoelectric oscillator arrangement mode of stack of transmitting probe employing, piezoelectric vibrator and pedestal adopt the gluing one that is connected into of high temperature bond, the wear-resisting entrant sound window that entrant sound window adopts fluorubber, silicon rubber or other insulation materials to make; Between pedestal 16 and drill collar, install the rubber pad of sound insulation additional.

4. state according to claim 2 or 3 with boring orientation acoustic logging device, it is characterized in that the groove width of leading sound track is respectively: 130mm, 110mm, 90mm, 110mm, the degree of depth is 14mm, the interval of leading sound track is respectively: 110mm, 90mm, 110mm.

According to described in claim 2 or 3 with boring orientation acoustic logging device, it is characterized in that: the exciting circuit of telemetry circuit produces the pumping signal of transmitting sonic system under the firing pulse effect from control and data processing circuit, operating frequency range 12～18kHz, the width of driving pulse is adjustable; Signal receives and data acquisition circuit comprises 4 identical autonomous channels of function, to amplifying from the different channel signals that receive each probe in sonic system, filtering, collection, four-way simulation programmable amplifier bandwidth 10～20KHz, four-way 14 digit wave form data acquisitions; Control and data handling system is take DSP and CPLD chip as core, control system is received after the control command from measurement-while-drilling system MWD, produce the required all control sequential of system works, pass through internal bus, work in coherent system between each several part, and be responsible for the transfer of data between mwd system, comprise channel gain, sampling depth, acquisition rate, send transmitter trigger pulse, gather startup command, and carry out real-time computing, storage to receiving the Wave data collecting; Power circuit power supply is 24～36VDC battery, and the MPU in power circuit, according to the instruction of mwd system, controls power source circuit switch and realizes intermittent duty.

6. according to claim 5 with boring orientation acoustic logging device, it is characterized in that: the non-volatile FLASH memory of the large capacity of storage of control and data handling system is stored log data.

7. according to claim 6 with boring orientation acoustic logging device, it is characterized in that: described memory adopts NAND FLASH chip to store as non-volatile data.

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