RU136487U1 - ACOUSTIC TELEMETRIC SYSTEM FOR MONITORING THE STATE OF THE OBSERVING WELL - Google Patents

Abstract

An acoustic telemetry system for monitoring downhole processes using a pipe string for transmitting data using acoustic waves, consisting of the ground part of receiving, recording and processing an acoustic signal and lowering the borehole part into the well, which includes an acoustic emitter unit, an acoustic transmitter module, an autonomous source power supply and measuring module, characterized in that the borehole part of the telemetry system is located directly below the pipe string, while under the bottom an acoustic emitter and a protective container are installed in series with a threaded pipe string using a threaded connection, inside which an acoustic transmitter module, an autonomous power supply and a measuring module are sequentially placed, and a resonant electrodynamic transducer tuned to a frequency of about 400 Hz with a relative radiation band is used as an acoustic emitter about 10%.

Description

The utility model relates to the field of hydrocarbon production and can be used to continuously transmit information measured in the reservoir at the mouth of the observation well in order to control well processes.

For the operation of stationary wireless telemetry systems that provide periodic measurement of downhole information and the delivery of measurement results to the surface of the well, it is most appropriate to transmit data through a tubing string using acoustic waves.

Known telemetry systems for transmitting downhole parameters using an acoustic communication channel with the transmission of measurement information through tubing strings (see, for example, patents US 4293936, IPC E21B 47/16, G01V 1/40, publ. 1981-10-06; US 5477505, IPC E21B 47/16, publ. 1995-12-19; IZ 7257050, IPC E21B 47/16, G01V 1/005, publ. 2007-08-14). Telemetry systems usually include a borehole unit containing an acoustic generator, a controller, a sensor system for measuring the required face parameters, a device for transmitting an acoustic signal to a production casing and ground-based signal receiving and analysis equipment.

To transmit an acoustic signal in known systems, column elements of the same length (pipes and couplings, respectively), which are an ideal periodic acoustic structure with clearly defined frequency bands of transparency and suppression, should be used. This condition imposes restrictions on the possibility of using known systems in practice, that is, when assembling columns of pipes of random arbitrary lengths.

The well-known ATS ™ telemetry system with an acoustic communication channel along the tubing string is designed for measuring runs when examining oil and gas wells on a lowered pipe string (see Acoustic Telemetry System ATS ™. // Testing & Subsea. H01910 01/10. Www.hallibarton .com, published at Presentation at the 2003 Offshore Technology Conference held in Houston, Texas, USA, 5-8 May 2003).

The well-known ATS ™ telesystem is not designed for long-term stationary use in production wells, which limits its application. In addition, this telemetry system is structurally complex.

Known telemetry system for controlling the parameters of the face, using a pipe string to transmit data using acoustic waves (see RF patent 112266, IPC E21B 47/16, G01V 1/40, publ. 10.01.2012), adopted as the closest analogue. The telemetry system comprises a ground-based signal receiving and processing module and a downhole module. The ground module is configured to register information signal parameters. The downhole module includes a downhole parameter measurement unit, an electronic unit as part of the controller, a bottomhole control circuit and an acoustic generator, a device for connecting and disconnecting from the pipe, which implements the downhole module fixing function inside the pipe string, an actuator that implements the function of creating an acoustic contact of the actuator with a pipe by pressing and introducing into the pipe wall material an element made of a material with a hardness exceeding that of the pipe material, as a stand-alone unit downhole module. When deploying the well-known telemetry system, measurements of intrinsic noise are made on the well head (fountain fittings), the working frequency range of the telemetry system is selected, and it is laid down in the bottom hole operation program.

The well-known telemetry system according to patent No. 112266 is built on the basis of two premises:

- the energy of the acoustic signals decays fairly evenly in the frequency band 100-3000 Hz, and in a real column screwed from the tubing using couplings, the dispersion of the sound velocity is weakly manifested, that is, the structure of the passband and signal suppression band. This premise, at least, is not always true for observation wells, therefore, it requires a critical approach;

- the linear attenuation coefficient of acoustic vibrations in the column is constant and, according to experimental data, it is estimated at 50 dB / km for the longitudinal vibration mode. This premise is at least physically incorrect. The attenuation coefficient of acoustic vibrations is usually due to several physical phenomena and therefore strongly depends on the frequency of vibrations. In addition, due to the variability of the manifestation of the totality of these physical phenomena, the linear attenuation coefficient depends on the position (depth) of the acoustic emitter.

In connection with the method of selecting the working frequency band adopted in the telesystem according to the prototype, and with the two prerequisites outlined, the acoustic emitter of the telemetry system should provide the ability to emit simple tonal pulses in an initially wide frequency range. Based on physical principles, such an acoustic emitter cannot be designed as a resonant mechanical oscillatory system, moreover, with a coordinated acoustic load in a wide frequency band (8 octaves). In practice, this means that the electro-acoustic efficiency of such an initially broadband acoustic emitter cannot be higher than a few percent. That is, taking into account the fact that an incorrect estimate of the attenuation constant of 50 dB / km can be noticeably underestimated, when implementing a telemetry system, insurmountable difficulties may arise in creating an electric power resource for downhole equipment for a long period of operation (for example, several years).

The objective of the proposed utility model is to create an acoustic telemetry system devoid of the aforementioned drawbacks of known similar solutions.

The technical result achieved using the utility model is to increase the efficiency of the acoustic communication channel and increase the reliability of the delivery of measured information to the surface of the well, which ultimately provides optimal control of the implementation of well processes.

The specified technical result is achieved using a combination of features common with the features of an acoustic telemetry system according to the prototype, such as:

- the presence in the telemetry system of the borehole and ground parts,

- the presence in the downhole part of equipment similar in functional purpose - an acoustic emitter, an acoustic transmitter module in the downhole control unit, an autonomous power supply module and a measuring module (with temperature, pressure, and other downhole sensors),

- the ground part performs the functions of receiving, recording and processing an acoustic signal,

and distinctive features from the prototype, such as:

- placement of the downhole part directly below the tubing string;

- installation under the lower pipe of the tubing string using a threaded connection of an acoustic emitter,

- installation under an acoustic emitter using a threaded connection of a protective container, inside which an acoustic transmitter module, an autonomous power source and a measuring module are sequentially placed;

- the use of a resonant electrodynamic transducer tuned to a relatively low frequency (about 400 Hz) with a relative emission band of about 10% as an acoustic emitter.

Placing the borehole part of the telesystem under the tubing string and using threaded connections for this purpose eliminates the need for complex mechanisms for fixing the borehole part in the tubing string and a reliable clamp to it, as is the case in the telescope system according to the prototype. The design as a whole is greatly simplified, and the reliability of the acoustic communication channel with the terrestrial part of the television system increases.

The use of a resonant electrodynamic acoustic transducer as an acoustic emitter (see patent KI 108895, IPC H04R 17/00, published September 27, 2011) provides an efficiency of converting electric energy into acoustic energy of 40-50 %%, increasing the efficiency and reliability of the channel communication with possible unpredictably high attenuation of the signal. An additional increase in the reliability of the communication channel is achieved through the use of so-called “complex signals”, which allow implementing a method of transmitting information that is adaptive to the conditions of signal interference that occurs when receiving at the wellhead. These advantages are due to the choice of acoustic signals corresponding to the real properties of the propagation medium, modulation methods, frequency band and power of the emitted signal.

The proposed utility model is presented in the drawings, which depict:

in FIG. 1 is a diagram of a general layout of an acoustic telemetry system in a well;

in FIG. 2 - spectral forms of the emitted (a) and received (b) acoustic signals;

in FIG. 3 - dependence of the specific attenuation of the acoustic signal in the frequency band 400 ± 50 Hz on the radiation depth;

in FIG. 4 - calculation estimate the transfer function of the model of the column NKT-73.

The acoustic telemetry system (see Fig. 1) consists of a borehole part lowered into the wellbore on a tubing string 1 connected by coupling joints (not shown), and a surface part located at the wellhead.

In the borehole part, under the lower pipe of the tubing string 1, a resonant electrodynamic acoustic emitter 2 is screwed. A protective container 3, which is a segment of the tubing, is screwed into the lower part of the acoustic emitter 2. Inside the protective container 3, an acoustic transmitter 4, a power source 5 and a measuring module 6 are sequentially suspended.

The ground part of the television system equipment (see Fig. 1) includes receiving accelerometers 7 installed on the fountain fittings of the well, and receiving and demodulating equipment connected by a signal cable 8. The receiving and demodulating equipment is placed in a metal cabinet 9 and consists of an analog signal input device; a computer designed to implement a method for transmitting information on complex noise-like signals that is adaptive to the conditions of signal propagation; microprocessor programmable time relay for turning on / off the power supply of ground equipment; GSM radio modem designed for session data transmission over the Internet; autonomous power supply (for wells with not supplied industrial power lines).

The acoustic telemetry system works as follows.

The controller of the module of the acoustic transmitter 4 according to a given schedule makes a request to the measuring module 6 to conduct measurements of downhole parameters. The measuring module measures, transmits information in the form of digital signals to the module of the acoustic transmitter 4 and goes into deep sleep mode. The controller of the module of the acoustic transmitter 4 modulates the complex signal with an information code and generates an electrical signal for the acoustic emitter 2. The mechanical oscillating system of the acoustic emitter 2 transmits the acoustic signal directly to the tubing string 1, along whose elements (pipes and couplings) the acoustic wave moves to the wellhead.

In the ground part, the signal is received by receiving accelerometers 7. In accordance with the schedule of communication sessions, power is supplied to the computer, the receiver program is launched, and the acoustic signal is demodulated and the information measured in the well is decrypted. At the end of the session for transmitting information from the bottom of the well, a communication session is conducted via GSM channels with posts of monitoring systems for the development of oil and gas fields.

An example of pilot production by a measuring complex using a cableless acoustic telemetric communication channel for continuous hydrodynamic monitoring of downhole parameters in an observation well of the Yuzhno-Russkoye field (Krasnoselkupsky district of the Yamalo-Nenets Autonomous District). The borehole part of the television system was at a horizon of about 995 meters. The electrodynamic acoustic emitter EDP-SZ stably kept the tuning frequency. The measured operating frequency band was 40 Hz, ranging from 375 Hz to 415 Hz. Temperature and pressure measurements were taken every 6 hours. Once a week, a communication session was conducted and the information stored in the acoustic transmitter 4 (see Fig. 1), transmitted to the ground part via the acoustic channel, was transmitted through the GSM network to the customer’s server. The telesystem functioned for seven months and stopped working due to a limited supply of power.

Examples of testing a prototype acoustic telemetry system at observation well No. 1001 of cluster No. 4 of the Romanovskoye field (near Muravlenko, Yamal-Nenets Autonomous District) according to the transfer function of the acoustic communication channel along the NKT-73 column (see Fig. 2) and an estimate of the attenuation of the acoustic signal (see FIG. 3).

In FIG. 2 (a) shows the spectrum shape of the emitted acoustic signal. In FIG. 2 (b) - the shape of the spectrum of the signal received by accelerometers at the mouth of the NKT-73 column; the spectral level of additive acoustic noise at the receiving accelerometer is shown here (the transfer function of the acoustic model of the NKT-73 column, built on the principles of electromechanical and electro-acoustic analogies, has been imposed). When calculating the model transfer function, a specific measure of a flat tool was used.

In FIG. Figure 3 shows an example of the dependence of the linear attenuation of the acoustic signal in the frequency band 400 ± 50 Hz on the radiation depth (NKT-73 column of 180 pipes with an average pipe length of 10.22 m). When the signal was received by accelerometers mounted on the upper pipe coupling, the total attenuation was about 73 dB. When an acoustic signal was received at a fountain, after a full installation of an ROS, the attenuation increased by about 20 dB.

In FIG. Figure 4 shows the estimated transfer function of the NKT-73 column model, built on the principles of electromechanical and electro-acoustic analogies, when arranging a column of pipes of random length with a uniform probability distribution of values in the range from 7.5 m to 10.5 m. Under simulated conditions, they remain for In practical use, only two transmission windows: the first and second. But, given the physical nature of acoustic noise, that is, a typical increase in their intensity towards low frequencies, under simulated conditions there remains a fairly unambiguous choice of the working frequency band: approximately 350-450 Hz.

The results, which consist in stable, efficient and reliable provision of remote control of temperature and pressure in the well, allow us to develop an industrial version of the telemetry system.

Claims (1)

An acoustic telemetry system for monitoring downhole processes using a pipe string for transmitting data using acoustic waves, consisting of the ground part of receiving, recording and processing an acoustic signal and lowering the borehole part into the well, which includes an acoustic emitter unit, an acoustic transmitter module, an autonomous source power supply and measuring module, characterized in that the borehole part of the telemetry system is located directly under the pipe string, while under an acoustic emitter and a protective container are installed in series with a threaded pipe string using a threaded connection, inside which an acoustic transmitter module, an autonomous power supply and a measuring module are sequentially placed, and a resonant electrodynamic transducer tuned to a frequency of about 400 Hz with a relative radiation band is used as an acoustic emitter about 10%.

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