Information transmission system

Abstract

A wireless downhole information transmission system is presented, which is preferably adapted for operation in a well (wellbore) and in particular in a well of the oil and gas and geothermal industry. The information transmission system comprises an elongated pipe (completion) having a plurality of pipe sections, including a first end pipe section and a last end pipe section, an information signal generator arranged at or near the first pipe section of the elongated pipe, the information signal generator being designed as a torsional wave generator for transmitting a torsional wave information signal along the elongated pipe, and an information signal receiver arranged at or near the last pipe section of the elongated pipe, wherein the elongated pipe between the signal generator and the signal receiver constitutes a carrier for transmitting the information signal between the signal generator and the signal receiver.

Description

Technical Field

[0001] This invention relates to data transmission systems, particularly for wells (wellbores), especially for wells in the oil and gas and geothermal industries. Background Technology

[0002] In the oil and gas industry, wells are used to produce hydrocarbons from reservoirs (production wells) or to inject fluids such as water, CO2, natural gas, steam, surfactants, polymers, and / or nitrogen into reservoirs (injection wells). Typically, such fluids are injected to increase hydrocarbon recovery from reservoirs by maintaining reservoir pressure, improving hydrocarbon displacement treatment, or reducing residual hydrocarbon saturation in the reservoir. In the geothermal industry, hot fluids, such as hot water, are produced from deep aquifers to the surface to collect heat for heating homes in cities and rural areas. The "cooled" water is then reinjected into the aquifer. More recently, CO2 injection has begun to aim at storing CO2 in depleted hydrocarbon reservoirs to reduce atmospheric CO2 concentrations, thereby curbing CO2 emissions and global warming.

[0003] Typically, a well has a wellbore lined with a steel tube, commonly referred to as casing or liner. The casing or liner is cemented into place within the overburden section to provide zonal isolation, preventing contamination of the shallow aquifer by deep reservoir fluids (i.e., oil / brine) and reducing the risk of unwanted fluid outflow from the overburden / shallow reservoir. Several options are available for reservoir section completions. The most common completion methods are open-hole and casing completions. In an open-hole completion, the reservoir section is not sealed through casing and cement. In a casing completion, the reservoir section is sealed through casing and cement. Most open-hole and casing completions also include tubing with packers (sometimes several packers are operated for selectivity within the reservoir) to seal the annulus between the tubing and the steel liner. In a casing completion, access to the reservoir is achieved through perforation of the casing / liner and cement. Open-hole completions to access reservoirs are typically achieved using perforated (pre-drilled) liners. It should be noted that these perforations can also be made later in the well's lifespan.

[0004] Once a well has completed production or injection, it can be opened to put it into service. When the well is opened, fluid will begin to move in and out of the wellbore. To gain understanding and control of events and to observe the flow dynamics within the wellbore, communication with objects (sensors or equipment) within the wellbore is useful, especially when data collection cables are not required. For example, when perforating a well to begin production, an explosive needs to be triggered when it reaches the location where it was perforated against the wellbore wall (e.g., casing and cement sheath). This is a delicate operation, as errors in information transmission can easily cause serious damage to the well (i.e., the aquifer is perforated instead of the oil-bearing layer). Therefore, the trigger signal must be transmitted safely to the igniter in the correct manner. When communication with a system at the surface is available, the downhole igniter can provide a response transmitted to the surface. Therefore, a two-way communication system is desirable. Other information that can be transmitted from downhole to the surface in real time through the well may include sensor information from downhole sensors and / or equipment, such as:

[0005] - Pressure and temperature data

[0006] - Flow (oil, water, and gas) data

[0007] - Fluid composition data

[0008] - Reservoir data (e.g., oil saturation)

[0009] -Integrity data (e.g., cement-bonded logging)

[0010] - Command data for downhole equipment (e.g., downhole valves / throttles, igniters)

[0011] - Response data from downhole commands (e.g., confirmation that a shot has been fired).

[0012] Because the total length from the reservoir to the surface (the top of the wellbore) can reach hundreds or even thousands of meters, it is difficult to send or retrieve such data or information (without using cables) to extraction facilities, such as those at the access point, and therefore requires continued development. Over the past few decades, both the depth and total length of wells have increased. Furthermore, the number of long-angle (extended) wells is constantly increasing, making it even more difficult to establish any communication or data exchange between the wellbore and the surface. Summary of the Invention

[0013] Therefore, the object of the present invention is to provide a system for establishing information exchange, which is achieved through a communication connection or data exchange via a transmission channel, particularly in a wellbore environment.

[0014] Another object of the present invention is to allow wireless communication between the two ends of a well completion (e.g., a slender pipe) to transmit, for example, a signal to activate a detonating perforation gun.

[0015] Another objective of this invention is to improve the reliability, accuracy, and quality of real-time and continuous information exchange between the two ends of a well completion (e.g., a slender pipe).

[0016] Another objective of this invention is to improve upon the aforementioned limitations.

[0017] The objectives of this invention are achieved through the subject matter of the independent claims. Preferred embodiments of the invention are the subject matter of the dependent claims.

[0018] Another object of the present invention is to provide a system and / or method for transmitting information through a transmission channel having increased speed and / or data density.

[0019] This invention proposes a wireless downhole information transmission system suitable in principle for operation in any facility providing well completion (e.g., a slender pipe). The information transmission system is preferably suitable for operation within the wellbore.

[0020] For example, a wellbore may include harsh environmental conditions such as pressures up to 60 MPa or temperatures up to 500 Kelvin. As the well's depth increases in the future, even higher temperatures and pressures may be encountered within the well. Such a wellbore may have open-hole sections and / or casing sections, and may include angles relative to vectors and / or gravity toward the Earth's center. In other words, the wellbore, or at least some sections of the wellbore, may have any orientation in the formation, including, for example, horizontal sections, which may even be preferred and intentionally drilled depending on the wellbore type. In fact, the orientation can even be partially upward. Such an upward-oriented wellbore may be needed when drilling alongside a selected layer (which contains natural resources, particularly hydrocarbons such as oil or gas) and the selected layer is not entirely horizontal but deviates upward or downward by a certain distance.

[0021] The range of wellbore fluids can be very broad. Wellbore fluids can include drilling mud (drilling fluid), brine (completion fluid), injected fluids such as steam, CO2, or nitrogen, or fluids from the reservoir such as water, oil, and / or gas. These fluids may contain solids and sediments such as sand, clay particles, scale deposits, barite, bitumen, and polymers.

[0022] Information transmission systems typically involve well completions consisting of elongated tubing, in most cases. This elongated tubing has multiple sections, including a first end section and a final end section. In other words, the tubing is arranged in sections that are connected to each other (e.g., screwed or welded together) to provide an overall elongated tubing. Thus, each section is connected to the adjacent section. Indeed, it has been found that the quality of each connection between two such sections is critical to the propagation of any signal along the tubing. However, even when each connection between two such sections is completed with great care, there is usually at least a variation in the outer diameter or wall thickness of the tubing in the area connected to the adjacent section. For example, if two sections are screwed together, the overall wall thickness is typically different at the location where the threads are present and where the two sections overlap in the threads compared to the overall wall thickness in the unthreaded portion of the tubing. This variation in material diameter and / or the connection between adjacent sections makes it difficult in practice to propagate any type of signal along such elongated tubing comprising multiple sections. For example, in a typical well, the elongated tubing can consist of 100 to 500 sections. In long-distance wells, the completion may even involve more pipe sections.

[0023] The information transmission system also includes an information signal generator located at or near the first end section of the slender pipe. In other words, a signal generator that applies information signals to the slender pipe is present at the first end of the slender pipe. The signal generator can be installed directly on the slender pipe, for example, directly around and circumferentially around the first end section. The signal generator can also be installed at the top section of the slender pipe, such as at the wellhead and / or at the Christmas tree (X-type Christmas tree) that is almost always present above the wellbore. Therefore, the signal generator is located at or near the first end section, and preferably in direct contact with the first end section.

[0024] The signal generator includes a torsional wave generator that transmits torsional wave information signals along a slender pipe. The information signal is provided as a torsional wave signal, wherein the slender pipe undergoes torsional deformation motion in order to propagate the information signal along the elongation axis of the slender pipe. Therefore, the slender pipe constitutes the information signal propagation path of the torsional wave information signal.

[0025] The information transmission system also includes an information signal receiver. The information signal receiver is installed at or near the very end (bottom) of the slender pipe. For example, when the slender pipe comprises 200 segments, the receiver may be installed in the last 10 or 20 segments. The receiver can then receive information signals, retrieve the information content of the information signals, and, for example, send any commands or transmit such commands to any nearby functional unit (such as the igniter of a perforating gun for perforating a well).

[0026] The information signal can be configured as a trigger signal and / or a short pulse signal. The information content will be relatively low, but it is sufficient in any case, such as an activation signal for a perforating gun. The information signal can also be encoded to provide information to a distinguishable receiver. For example, the information signal can include an identification signal section such as the start or end of the signal, whereby the receiver can recognize the specific signal form because the particular information signal is dedicated to it. For example, several such signal-encoded receivers can be mounted in the same elongated pipe, and even when some or all receivers receive the same signal, the dedicated receiver will recognize the corresponding information signal of that same signal and read the corresponding information.

[0027] Information signals can also be encoded to provide distinguishable information. Any encoding method, such as amplitude modulation, can be used.

[0028] A slender conduit extends between its first and last end sections, thus connecting a signal generator mounted at or near the first end section and a receiver mounted at or near the last end section. Since the slender conduit constitutes the carrier for transmitting information between the signal generator and the signal receiver, it forms part of an information signal transmission system. The slender conduit undergoes one (or more) torsional bends, and the cohesive force of the material within the slender conduit causes torsional waves to pass through and propagate along the material from the signal generator to the signal receiver.

[0029] The information signal generator can preferably be designed as a transceiver, meaning that the generator can send information signals and, for example, receive information signals from a signal receiver. Similarly, the information signal receiver can also be designed as a transceiver. If both the signal generator and the signal receiver are designed as transceivers, bidirectional information exchange can be established between them.

[0030] In a preferred embodiment, the information signal can be provided in the form of a resonant frequency suitable for the characteristics of a slender conduit and / or suitable for the total distance between the information signal generator and the information signal receiver.

[0031] Furthermore, the system may include one or more additional information signal receivers arranged along or near the slender conduit. Thus, for example, a signal receiver can be assigned to each functional device installed at or within the slender conduit.

[0032] The information signal generator preferably includes at least one piezoelectric actuator. The piezoelectric actuator can convert electrical signals into acoustic signals, and vice versa. Therefore, the piezoelectric actuator can be used as a transceiver.

[0033] A piezoelectric actuator may include one or more piezoelectric discs stacked in a row. Using multiple piezoelectric discs can increase the overall signal amplitude. For example, the piezoelectric discs can be driven in parallel in an acoustic sense and / or in series in an electrical wiring sense. Each piezoelectric disc may include a thickness ranging from 1 mm to 5 mm, with a thickness of about 2 mm or less appearing to be preferred.

[0034] The signal generator may also include two or more piezoelectric actuators arranged on opposite sides of the pipe's elongation axis and / or symmetrically or at equal angles around the pipe's elongation axis. Thus, for example, each acoustic generator or each piezoelectric actuator may be arranged perpendicular to the pipe's elongation axis, but not necessarily facing the slender pipe. However, in one example, the acoustic generator is arranged facing the slender pipe and perpendicular to its elongation axis.

[0035] The information signal generator may alternatively or cumulatively include one or more magnetostrictive actuators, such as disks, which operate very similarly to the aforementioned piezoelectric actuators. When an alternating magnetic field is applied, each magnetostrictive actuator or each magnetostrictive disk alternately expands and contracts, thereby emitting a wave signal of a selectable frequency.

[0036] For example, in relatively low frequency ranges (e.g., in the 2 Hz to 1 kHz frequency range, such as in the 100 Hz ± 80 Hz or ± 20 Hz range), mechanical actuation can even be used, such as by using a pendulum to generate wave signals of selectable frequencies.

[0037] The information signal may include frequencies in the range of 2 Hz to 20 kHz. The information signal may also include frequencies in the following ranges: above 2 Hz, above 500 Hz, above 1 kHz, above 2 kHz, or above 5 kHz. Simultaneously or unrelatedly, the information signal may also include frequencies in the following ranges: below 25 kHz, below 20 kHz, below 15 kHz, below 10 kHz, or below 8 kHz. The frequency also depends on certain characteristics of the elongated conduit, such as the material of the elongated conduit, the weight of the conduit, the wall thickness of the conduit, and / or the total length of the conduit or the length between the signal generator and the signal receiver. In other words, the frequency of the information signal may be selected within the aforementioned range or limitations, and the frequency of the information signal is suitable for the elongated conduit, wherein the information signal should propagate along the elongated conduit to transmit the information carried by the information signal. In this sense, for example, for shorter or even shorter elongated conduits and / or shorter distances to the next signal repeater or signal receiver, a higher frequency may be selected for the information signal to, for example, transmit more information to, for example, increase the data rate.

[0038] At least one repeater can be positioned between the information signal generator and the information signal receiver. This repeater can be designed to resemble the signal receiver, such that at least one of the information signal receivers is designed as a repeater that transmits the information signal to the next repeater and / or to an information signal receiver positioned at or near the end of the elongated pipe. However, for example, one or more repeaters can be designed as transceivers, and the signal receiver does not necessarily have the ability to transmit signals. However, in a setup where the signal receiver should also be able to transmit signals, all units can be designed as transceivers. For example, when the receiver is designed as a transceiver, functions such as setting and reporting valve function or valve status can also be implemented via the receiver, and values ​​such as temperature, pressure, or fluid velocity of well fluid in the elongated pipe can also be transmitted. The information transmission system can even be designed so that the signal generator is located downhole and "reports" fluid properties. Then, the generator transmits the torsional wave information signal to a signal receiver along a slender pipe, which is installed at the top of the well (e.g., at the wellhead or X-shaped tree) or at the last pipe section. The signal receiver receives the aforementioned signal.

[0039] Each repeater is preferably designed to use distinguishable coding. This ensures that when any receiver or repeater receives a signal from the transmitter that is not intended for use with a particular receiver or repeater, the signal can be identified and the corresponding receiver or repeater can ignore it. In other words, through the distinguishable coding of the torsional wave information signal, the corresponding receiver or repeater can identify and read the signal intended for use with that specific receiver or repeater.

[0040] For example, for slender pipes, additional repeaters can be used to amplify the information signal for every 1500 meters or more of extension. However, if possible, the aim is to transmit the information signal without any repeaters. Depending on the characteristics of the slender pipe, additional repeaters for signal amplification can also be installed for every 1000 meters or more, or every 500 meters or more, or every 100 meters or more.

[0041] Signal recognition can be improved through autocorrelation, enabling the receiver to provide a processing device designed to provide autocorrelation of the received information signal. For example, predefined signal patterns can be stored in the receiver (e.g., in a storage device such as a memory), and the receiver can compare the stored signal patterns with the received signal. When the correlation between the stored signal and the received signal matches, the receiver receives the information. In this way, the signal-to-noise ratio can be significantly improved.

[0042] The information transmission system preferably provides automatic tuning capability, wherein both the signal generator and the signal receiver are designed as transceivers, and wherein the frequency range is tested and at least one resonant frequency is confirmed by, for example, the signal receiver or the signal generator.

[0043] For example, an information signal receiver is connected to one or more perforation units in the wellbore, wherein the information signal includes an ignition signal for detonating an ignition unit (igniter) or detonating one or all ignition units.

[0044] The slender pipe that serves as the propagation channel for the torsional wave information signal is preferably made of metal, such as steel.

[0045] At least one information signal receiver may additionally include an energy storage device (e.g., a battery pack) to provide electrical power to the information signal receiver. Electrical power can be supplied to the information signal receiver from the battery pack, enabling the receiver to operate autonomously.

[0046] The present invention also includes an information signal generator for a downhole information transmission system (such as the downhole information transmission system described above). This information signal generator is designed to transmit information signals along an elongated conduit. For this purpose, the signal generator includes at least one wave generator arranged perpendicularly or substantially perpendicularly to the elongation axis of the elongated conduit to generate wave information such as torsional wave information. In other words, preferably, the wave generator includes a wave emission direction oriented perpendicularly or substantially perpendicularly to the elongation axis of the elongated conduit. Therefore, the wave emission direction is not along the elongated conduit and does not point in the direction of the conduit, but rather emits waves in a transverse direction to the elongation axis of the conduit. Additionally, the wave generator can be positioned off-center, not at the center of the elongated conduit, but at or near the side of the conduit, such that the wave is transmitted tangentially to the elongated conduit.

[0047] For example, it is not even possible to emit torsional waves when the wave generator is oriented along the elongation axis of a slender pipe. In this case, the wave generator should "twist" the slender pipe to introduce shear forces into it. Therefore, the force impact should include a tangential component along the slender pipe to force shear strain into it. However, when the wave generator is oriented along the elongation axis of the slender pipe, this tangential component can be negligible. Nevertheless, especially due to the connections between multiple elements in a typical slender pipe, transmitting information signals via torsional wave signals may be advantageous, for example, in terms of signal damping.

[0048] A sound wave generator may include one or more piezoelectric actuators or may consist of one or more piezoelectric actuators.

[0049] The signal generator is preferably located at or near the top of the slender pipe, for example, at the top of the slender pipe, such as at the wellhead and / or the X-shaped wellhead.

[0050] Preferably, the signal generator includes a circumferential portion, wherein at least one acoustic wave generator is arranged on the circumferential portion such that the acoustic wave generator exposes the circumferential portion to at least one acoustic wave, and the circumferential portion transmits the at least one acoustic wave to the elongated pipe. The circumferential portion may be designed to surround the elongated pipe, in other words, the circumferential portion is circumferentially closed around the elongated pipe, or the circumferential portion is annular and arranged around the elongated pipe. Thus, the circumferential portion can convert the at least one acoustic wave emitted by the acoustic wave generator into at least one torsional wave.

[0051] The circumferential portion preferably includes an inner side facing the elongated pipe during installation. The outer side of the circumferential portion is away from the elongated pipe; for example, a sound wave generator is arranged on this outer side of the circumferential portion. Furthermore, the circumferential portion may include a circumferentially constricted portion on the inner side. This constriction reduces the total surface area of ​​the circumferential portion in contact with the elongated pipe.

[0052] The circumferential portion can be mounted onto a slender pipe to form good surface contact, for example by increasing the contact pressure of the circumferential portion on the slender pipe, so as to improve signal propagation from the sound wave generator to the slender pipe.

[0053] The acoustic wave generator may include a stack of piezoelectric actuators, where each piezoelectric actuator may be a piezoelectric disk. All the disks can then be stacked on top of each other and connected in series, so that all the piezoelectric elements can contribute to the signal amplitude of the acoustic wave signal generated by the piezoelectric disks, and thus increase the amplitude of the information signal.

[0054] An acoustic wave generator advantageously includes an end mass disposed on top of the generator. In other words, when the acoustic wave generator comprises a stack of piezoelectric discs, the end mass is disposed on top of the stack to further amplify the signal amplitude. Specifically, the end mass is arranged to contact the first or last piezoelectric disc of the stack. For example, the end mass may comprise a diameter approximately the same as the diameter of the piezoelectric discs. The end mass can be made of iron or any other reasonably heavy material; of course, material cost may influence the choice of the appropriate material for the end mass.

[0055] The signal generator may comprise two acoustic wave generators arranged opposite to each other. The two acoustic wave generators are preferably arranged at the same position relative to the longitudinal extension of the pipe, but on opposite sides of the pipe. However, from a technical perspective, the two acoustic wave generators can also be positioned relative to each other at any angle, where an opposite arrangement appears to result in a higher achievable signal amplitude and is therefore preferred.

[0056] The signal generator may include multiple acoustic wave generators (two or more) arranged at equal angles to each other. In other words, the acoustic wave generators are preferably all perpendicular to the extension direction of the pipe and arranged around the pipe at an angular distance (preferably equidistant from each other). Similarly, multiple acoustic wave generators can be arranged at other angular distances relative to each other, but an equal-angle arrangement appears to provide a higher overall signal amplitude.

[0057] However, the signal generator may preferably include at least two acoustic wave generators distributed along the elongation axis of the slender pipe, such that each acoustic wave generator is capable of amplifying the torsional wave information signal. For example, when the acoustic wave generators are arranged such that their distances relative to each other correspond to multiple wavelengths, or when the acoustic wave generators are arranged very close to each other, such as adjacent but not in the same vertical plane (perpendicular to the elongation axis of the pipe), at least two acoustic wave generators may be activated simultaneously and in the same phase. Alternatively, when the acoustic wave generators are activated synchronously but the phase points of the information signals are different, the two acoustic wave generators may be arranged such that their distances correspond to, for example, a portion of the wavelength (e.g., half the wavelength).

[0058] According to the present invention, an information signal receiver is also provided for use in, for example, a downhole information transmission system as described above, and for receiving torsional wave information signals propagating along an elongated pipe. The information signal receiver includes at least one transducer device designed to receive and convert the received wave information signals, such as torsional wave information signals. The transducer device is arranged at or near the elongated pipe and extends perpendicularly to the pipe's elongation axis. In other words, preferably, the wave receiver or transceiver includes a wave receiving (or wave emitting) direction, wherein the wave receiving direction is oriented perpendicular or substantially perpendicular to the elongation axis of the elongated pipe. Therefore, the wave receiving direction does not follow the elongated pipe and does not point towards the pipe direction, but rather detects / measures the wave in a transverse direction along the pipe's elongation axis. Additionally, the wave receiver can be positioned off-center, not at the center of the elongated pipe, but at or near the side of the pipe, such that the wave propagates tangentially into the elongated pipe. This arrangement greatly improves the detection of waves such as torsional waves. For example, when the wave receiver is oriented along the elongation axis of a slender pipe, it may not even be possible to detect a torsional wave.

[0059] The information signal receiver may alternatively or cumulatively include one or more magnetostrictive actuators.

[0060] The information signal receiver also includes a housing, which is, for example, shaped into an elongated or tubular form, for fitting into a pipe or wellbore.

[0061] The information signal receiver may also include at least one second transducer device arranged opposite to the transducer device. Additionally or alternatively, the transducer device or the second transducer device may include one or more acoustic wave receivers, such as piezoelectric plates.

[0062] Furthermore, the information signal receiver preferably includes an internal transducer mounting device, wherein at least one transducer device is mounted on the internal transducer mounting device facing the housing of the information signal receiver.

[0063] At least one transducer device may each include an end block between at least one acoustic receiver and a housing, preferably with one side of the end block contacting the acoustic receiver and the other side of the end block contacting the inside of the housing. In other words, the end block may be designed to fill the space between the transducer device and the inside of the housing. In this way, a form-fitting contact can be established between the acoustic receiver and the housing. When, for example, the housing forms part of an elongated pipe, the transducer device is in direct contact with the elongated pipe, although the transducer device is not directly arranged on the side of the elongated pipe but is spaced apart by the end blocks. In other words, when the housing of the acoustic receiver is a segment of an elongated pipe, the acoustic receiver may be mounted inside the elongated pipe, arranged on the inside of the pipe and with all sides of the acoustic receiver surrounded by the elongated pipe, and should be in mechanical contact with the elongated pipe.

[0064] The information signal receiver may also include: a battery compartment for storing electrical energy; and an electronic device compartment that may additionally or alternatively include an analog-to-digital converter.

[0065] The signal receiver may also have a connector for mounting the information signal receiver to a slender conduit. In other words, when the signal receiver comprises a pipe segment, the connector can be used to connect that pipe segment to the rest of the conduit. The connector may also be connected to, for example, a continuous compartment containing explosives (i.e., a perforating gun).

[0066] The signal receiver preferably includes sensor devices such as a depth correlator or a pressure sensor. The depth correlator may include gamma rays to correlate gamma ray intensity with a specific depth level in the wellbore. Alternatively, a CCL (casing coupling locator) can be used for depth correlation. The depth correlator can be implemented using pressure and temperature sensors. A combination of the aforementioned technologies can provide higher accuracy in depth measurement. However, it can be noted that when the slender pipe is composed of pipe segments, the length of each segment is quite precise, allowing the depth of the signal receiver to also be obtained by measuring (or “counting”) the number of pipe segments positioned above the signal receiver unit and below the wellbore.

[0067] At least one transducer device may include a stack of piezoelectric discs as acoustic wave receivers. Such a stack of piezoelectric discs or plates is preferred because it can improve the overall signal strength in both receiving signals and transmitting any torsional wave information signals.

[0068] Therefore, the information signal receiver is preferably designed as a transceiver capable of receiving and transmitting torsional waves in a slender pipe using an acoustic wave receiver such as a piezoelectric plate.

[0069] In a preferred embodiment, the transducer device of the signal receiver is designed to harvest energy from the fluid movement of the well fluid flowing through a narrow conduit. In other words, the fluid movement causes the transducer (sound receiver) to move, and when the transducer moves, an electric current is generated. This current, and thus electrical energy, can be stored or used to keep the electronics of the information signal receiver operational.

[0070] Another aspect of the invention relates to a perforating gun for use in downhole environments, for example, in conjunction with the downhole information transmission system detailed above. The perforating gun includes at least the information signal receiver described above.

[0071] The invention will now be described in more detail with reference to preferred embodiments. Referring to the accompanying drawings, the same reference numerals are used for the same or similar components. Attached Figure Description

[0072] The following figures illustrate:

[0073] Figure 1 It is a schematic cross-sectional view of a formation with a signal transmission system in a well (wellbore);

[0074] Figure 2 This is another schematic cross-sectional view of a formation with a signal transmission system in a wellbore having a horizontal section partially covered by a liner;

[0075] Figure 3 This is a perspective view of a signal generator installed on a pipe section;

[0076] Figure 4 This is a top view of a signal generator installed on a pipe;

[0077] Figure 5 This is a diagram of another signal generator installed on the pipeline;

[0078] Figure 6 This is a perspective view of an embodiment of the signal receiving unit;

[0079] Figure 7 This is a side view of an embodiment of the signal receiving unit;

[0080] Figure 8 This is a perspective view of a partially open signal receiving unit;

[0081] Figure 9 This is a top view of the partially opened signal receiving unit;

[0082] Figure 10 This is another perspective view of the partially opened signal receiving unit;

[0083] Figure 11 This is a side view of an embodiment of a signal transmission system with a perforating gun used downhole. Detailed Implementation

[0084] exist Figure 1 In this process, a borehole (wellbore) 2 is drilled into the formation 4 to extract natural resources such as oil or gas. The wellbore 2 extends continuously from the surface 6 to the reservoir 8. The wellhead 10 is located at the top of the wellbore. The wellhead may include a "tree". The well is connected to the extraction facility 9.

[0085] A casing 12, in the form of a long, thin steel pipe or conduit, is located within the wellbore 2 and extends from the surface near the wellhead 10 to the underground section of the wellbore 2. Inside the casing 12, a conduit 14 comprising multiple pipe segments (pipe sections) 15 is arranged, each segment being connected into a continuous pipe section 15 by any type of connector 18 (e.g., a spiral connector). In this embodiment, the first pipe section 152 is connected to the wellhead 10 and includes a signal generator 40. The "lowest" or last pipe section 154 includes a signal receiver 20. Since the conduit 14 serves as a carrier for information signals propagation downhole and / or along the conduit 14, the information transmission system includes a signal generator 40 at the wellhead, the conduit 14 as the signal carrier, and the downhole signal receiver 20.

[0086] Wellbore is typically filled with wellbore fluids 16. The range of wellbore fluids can be very broad. Wellbore fluids can include drilling mud (drilling fluid), brine (completion fluid), injected fluids (steam, CO2, or nitrogen), or fluids from the reservoir such as water, oil, and / or gas. These fluids may contain solids and sediments such as sand, clay particles, scale deposits, barite, bitumen, and polymers.

[0087] When pipe 14 is lowered to a depth of interest (e.g., the depth at which perforation should be performed or valves should be read in the wellbore), pipe 14 typically only partially involves the wellbore. Pipe 14 may be permanently installed in the well, or pipe 14 may be temporarily lowered into the well, for example, in the case of planned perforation.

[0088] Signal receiver 20 is located in wellbore 2 as part of conduit 14, therefore signal receiver 20 includes a section 154 of conduit 14. Advantageously, it has an internal power storage device 92 (see example...). Figure 6The signal receiver 20 operates autonomously, therefore it does not require external power supply or wiring. Since no wiring needs to be considered, and there are no limitations on the depth of use as part of the total length of the conduit 14, this construction simplifies the installation and handling of the signal receiver 20.

[0089] In summary, by adding pipe segment 15 to the pipe 14 between the first pipe segment 152 and the last pipe segment 154, the signal receiver 20 can be positioned quite freely in the wellbore 2, thereby lowering the signal receiver 20 into the wellbore 2 and, in particular, eliminating the need for a cable connection to the surface. It can be added that the signal receiver 20 is not necessarily installed at the very end of pipe segment 15; other downhole devices can be lowered below the signal receiver 20, see, for example... Figure 11 The perforating gun 70 is installed in the last pipe section 154, and the signal receiver 20 is installed in another pipe section 15 located above it.

[0090] Figure 2 Another embodiment of a formation 2 with a signal receiver 20 located in the horizontal section of conduit 14 is shown. In this embodiment, casing 12 and conduit 14 terminate in wellhead 10. Signal generator 40 is arranged in or at wellhead 10. Well 2 is drilled at an angle to the production direction of interest, particularly horizontally in the area of ​​the last section 154.

[0091] Go to Figure 3 An embodiment of a signal generator 40 mounted to pipe segment 15 is schematically illustrated. The signal generator 40 includes a circumferential portion 50 clamped to the pipe segment 15 by a fixing device 52. To further improve the contact pressure of the circumferential portion 50 on the pipe segment 15, a contraction portion 42 is located inside the circumferential portion 50. Two acoustic wave generators 44 are arranged on opposite sides of the pipe segment 15 and perpendicular to the elongation axis of the pipe segment 15. The acoustic wave generators 44 can apply a force to the circumferential portion, which in turn transmits this force to the pipe segment 15, initiating a slight rotational movement within the pipe segment 15. Thus, the acoustic waves generated by the acoustic wave generators 44 are converted into a torsional wave signal and applied to the pipe segment 15. The pipe segment 15 then transmits the torsional wave signal along its extension and through any connector 18 to adjacent pipe segments 15, and thus along the elongated conduit 14 to the signal receiver 20.

[0092] Figure 4A top view of pipe segment 15 on which a signal generator 40 is mounted is shown. The signal generator 40 has a circumferential portion 50 with a contraction section 42 and two acoustic wave generators 44 opposite to each other. Each acoustic wave generator 44 includes a stack of multiple piezoelectric discs 46 that together generate acoustic wave signals. The signal timing of the two acoustic wave generators 44 is accomplished in such a way that the two acoustic wave generators include the same signal phase, and then the signal phases are added together to obtain the total signal amplitude of the excitation torsional wave signal.

[0093] Figure 5 A perspective view of an embodiment of a signal generator 40 mounted to pipe segment 15 is shown. The signal generator 40 includes four acoustic wave generators 44 mounted approximately equiangularly around pipe segment 15 and approximately perpendicular to the pipe's elongation axis. A piezoelectric disc 46 is connected via an electrical connection 54 to transmit current to the piezoelectric disc 46, which, acting as a transducer, converts the current into an acoustic signal. The acoustic waves generated by the acoustic wave generators 44 are then converted into a torsional wave information signal, which can propagate along pipe segment 15 from the first pipe segment 152 to the last pipe element 154 where a signal receiver 20 is mounted.

[0094] Now refer to Figure 6 A schematic perspective view of an embodiment of the signal receiver 20 is shown, in which various technical devices inside the signal receiver 20 housed in a housing 28 can be seen. For clarity, the housing 28 is depicted as partially transparent. The signal receiver 20 is designed to be mounted or mated with other segments 15 of an elongated conduit.

[0095] In this embodiment, an end cap is disposed on one side of the signal receiver 20, allowing the signal receiving unit 20 to be installed as the final tube segment 154, wherein other tube segments 15 are connected to the signal receiving unit 20 via a connector 18 disposed on the other side of the signal receiving unit 20. The signal receiver includes a receiver 24 mounted on an internal transducer mounting device 30. The receiver 24 is connected to an electronics compartment 34, for example, where an analog-to-digital converter and processing electronics may be housed, via an electrical connection 54. Furthermore, a battery pack 92 is installed to provide power for operating the signal receiving unit 20.

[0096] The diameter of the casing 28 can be selected, for example, with respect to the diameter of the wellbore and / or the diameter of the pipe 14. The casing 28 can, for example, have an outer diameter of 73 mm and an inner diameter of 55 mm, resulting in a casing thickness of approximately 18 mm. However, the outer diameter of the casing 28 is preferably in the range of 50 mm to 90 mm.

[0097] The signal receiving unit 20 also includes a sensor 60, such as a pressure and temperature sensor and / or a gamma ray detector, through which the depth in the well can be estimated. As an example in the embodiment, when the signal receiving unit 20 is positioned as an igniter to trigger the perforating gun 70, the measurement value of the pressure sensor 60 can be read as a safety measure if the receiving unit 20 can trigger the perforating gun 70. When the pressure is sufficiently high, the signal receiving unit 20 can trigger the igniter, and the perforating gun 70 can be safely fired downhole. In summary, the signal receiver 20 is designed to receive an information signal including an activation signal for firing the perforating gun 70, sent by the signal generator 40, and can trigger the igniter to fire the perforating gun 70.

[0098] Figure 7 A side view of the signal receiving unit 20 is shown, with the internal components visible again within the housing 28, which is depicted as partially transparent. Two signal receivers 24 are mounted on the internal transducer mounting device 30 (mounting plate).

[0099] exist Figure 8 Another perspective view of the partially opened signal receiving device 20 is shown in the figure. The installation of two signal receivers 24 can be seen in this figure. The two signal receivers 24 are mounted on the internal transducer mounting device 30. Each signal receiver 24 includes a stack of piezoelectric discs 46 and an end block 48. The end block is arranged between the piezoelectric discs 46 and the inner side 32 of the housing 28, with one side of the end block in physical contact with the inner side of the housing 28, and the other side of the end block in physical contact with at least one of the piezoelectric discs 46 and / or the stack of the piezoelectric discs. This arrangement ensures both space-saving installation of the signal receivers 24 and high sensitivity of the signal receivers 24.

[0100] Figure 9 A cross-sectional view through the signal receiving unit 20 is shown. Figure 9 The diagram illustrates the arrangement of two signal receivers 24. The two signal receivers are physically contacted with the inner side 32 of the housing 28 via end blocks 48, which are positioned on top of a stack of piezoelectric discs 46, which in turn are mounted on the transducer mounting device 30. This entire arrangement allows the torsional wave information signal to be transmitted to the signal receivers 24, thereby improving the signal-to-noise ratio of the received information signal.

[0101] exist Figure 10 The image shows a cross-sectional perspective view of an electronics compartment 34 in which a battery pack 92 and some electronic devices 80 are installed. In this case, the electronics compartment 34 also houses a printed circuit board with some processing devices.

[0102] Figure 11The setup using the information transmission system as presented herein is illustrated. A signal generator 40 is installed near or at the wellhead 10, and one or more pipe sections 15 are arranged below the wellhead and positioned to reach a first signal receiving unit 20a installed below it. The first receiving unit 20a is located in the wellbore, for example, hundreds or even thousands of meters below the wellbore opening, which is typically located at the surface.

[0103] The igniter and perforating gun 70a are mounted adjacent to the first signal receiving unit 20a. The igniter and perforating gun 70a can be positioned directly below the first signal receiving unit 20a. For example, the igniter and perforating gun 70a can also be wired to the first signal receiving unit 20a, which is located tens or hundreds of meters away from the perforating gun. This arrangement is suitable, for example, when the signal receiving unit must be at a certain distance from the explosion zone that will be generated when the perforating gun is fired.

[0104] One or more additional pipe sections 15 connect the perforating gun 70a to a second signal receiving unit 20b, which is installed adjacent to the second perforating gun 70b. Another pipe section 15 connects the second perforating gun 70b to a third signal receiving unit 20c, which in turn connects to a third perforating gun 70c, and so on. For example, this method can be used to operate ten perforating guns 70 simultaneously in the wellbore and fire sequentially in a single operation. In this way, the pipe 14 only needs to be placed in the well once to perform all necessary perforations in the well.

[0105] When the perforating guns 70, 70a, 70b, and 70c fire, the first information signal is transmitted to the final receiving unit. Figure 11 In the example, the last receiving unit is the third receiving unit 20c. The information signal may include an coded trigger signal that causes the third perforating gun 70c to fire. Other signal receiving units 20a and 20b may receive this signal, but may be programmed not to trigger the perforating guns associated with those other signal receiving units 20a and 20b. Alternatively, the other signal receiving units 20a and 20b may be programmed to repeat or amplify the received trigger signal addressed to the third receiving unit 20c. Thus, receiving units 20a and 20b can be used as repeaters in the elongated pipe 15. When the third signal receiver 20c triggers the third perforating gun 70c, the third receiving unit 20c may no longer be reachable due to a fault or damage. Therefore, the lowest perforating gun 70c should fire first, followed by the next nearest perforating gun 70b, and finally the perforating gun 70a.

[0106] In other words, this invention allows multiple perforating guns to be fired via individual commands for each gun. All of this can be accomplished with just one downhole run instead of several. This reduces the time required for perforation, thus reducing production delays and increasing revenue. The proposed information transmission system also allows for secure long-distance information transmission, where wired communication is undesirable, difficult, or even impossible due to wellbore height variations. Furthermore, the extension of large / long cable lengths can lead to wiring failures and is therefore no longer necessary.

[0107] It should be understood that features defined herein according to any aspect of the invention or with respect to any specific embodiment of the invention may be used alone or in combination with any other features or aspects of the invention or embodiments. In particular, the invention is intended to cover information signal transmission systems including any features described herein, as well as signal generators, information signal receivers, and perforating guns. It should generally be understood that any feature disclosed herein, whether or not it is disclosed in the specification, claims, and / or drawings, may be a fundamental feature of the invention on its own, even if disclosed in combination with other features.

[0108] It should also be understood that the above embodiments of the present invention have been described by way of example and illustration of their principles only, and further variations and modifications can be made to the embodiments of the present invention without departing from the scope of the present invention.

[0109] List of reference numerals

[0110] 2 boreholes

[0111] 4. Stratigraphy

[0112] 6. Ground

[0113] 8. Reservoir

[0114] 9. Extraction (Production) Facilities

[0115] 10 Wellhead

[0116] 12 casings

[0117] 14 Pipelines

[0118] 15. Pipeline sections

[0119] 16 Wellbore Fluids

[0120] 18 Pipe Connectors

[0121] 20 Signal Receiver / Receiving Unit

[0122] 24. Signal generator for receiver and / or receiving unit

[0123] 28. Housing or outer casing of the receiving unit

[0124] 30 Internal transducer mounting equipment / plate

[0125] 32. Inner side of the shell

[0126] 34 Electronic Components Compartment

[0127] 36 End Caps

[0128] 40 Signal Generator

[0129] 40a Second Signal Generator

[0130] 42. Contraction section

[0131] 44. Acoustic wave generator or piezoelectric actuator

[0132] 46 Piezoelectric disc

[0133] 48 end blocks

[0134] 50 Zhou Xiangbu

[0135] 52 Fixing device

[0136] 54 Electrical connection parts

[0137] 60 sensors

[0138] 70 Igniter with firing port gun

[0139] 80 Receiver electronics, such as printed circuit boards

[0140] 92 Independent power supply

[0141] 152 First Pipe Section

[0142] 154 Last pipe section.

Claims

1. A downhole information transmission system suitable for operation in a wellbore (2), the downhole information transmission system comprising: The elongated pipe (14) has multiple pipe segments (15), including a first end pipe segment (152) and a last end pipe segment (154). An information signal generator (40) is disposed outside the elongated pipe (14) and at or near the first end section of the elongated pipe, and is designed as a torsional wave generator that transmits torsional wave information signals along the elongated pipe. An information signal receiver (20) is disposed at or near the last end section of the elongated pipe. The elongated conduit between the information signal generator and the information signal receiver constitutes a carrier for transmitting the torsional wave information signal between the information signal generator and the information signal receiver. The torsional wave information signal includes frequencies in the range of 2kHz to 20kHz.

2. The downhole information transmission system according to claim 1, in, The torsional wave information signal is provided in the form of a trigger signal and / or a short pulse signal, and / or The torsional wave information signal can be encoded to provide information to a distinguishable information signal receiver (20) and / or provide distinguishable information.

3. The downhole information transmission system according to claim 1, characterized in that, The information signal generator (40) is designed as a transceiver, and / or The information signal receiver (20) is designed as a transceiver.

4. The downhole information transmission system according to any one of the preceding claims, characterized in that, The torsional wave information signal is provided in the form of a resonant frequency, which is adapted to the characteristics of the elongated pipe (14) and / or to the total distance between the information signal generator (40) and the information signal receiver (20).

5. The downhole information transmission system according to claim 1 further includes one or more additional information signal receivers arranged along or near the elongated pipe (14).

6. The downhole information transmission system according to claim 1, wherein, The information signal generator (40) includes at least one piezoelectric driver.

7. The downhole information transmission system according to claim 6, in, The piezoelectric actuator includes one or more piezoelectric disks (46) stacked in a row, and / or The information signal generator (40) includes two or more piezoelectric actuators arranged on opposite sides of the elongation axis of the elongated pipe (14) and / or symmetrically or at equal angles around the elongation axis of the elongated pipe (14).

8. The downhole information transmission system according to claim 5, It also includes at least one repeater disposed between the information signal generator (40) and the information signal receiver (20), and / or in, At least one of the additional information signal receivers is a repeater, which is designed to pass the information signal to the next repeater and / or to the information signal receiver (20) located at or near the last end section of the elongated pipe.

9. The downhole information transmission system according to claim 8, in, Each repeater is designed to use distinguishable coding, and / or Wherein, for every 1500 meters or more, or every 1000 meters or more, or every 500 meters or more, or every 100 meters or more, an additional repeater is used to amplify the torsional wave information signal of the slender pipe (14).

10. The downhole information transmission system according to claim 1, wherein, Improving signal recognition through autocorrelation, and / or wherein the information signal receiver (20) is provided with a processing device (80) designed to provide autocorrelation of the received torsional wave information signal.

11. The downhole information transmission system according to claim 1, wherein the system provides automatic tuning capability, wherein, Both the information signal generator (40) and the information signal receiver (20) are designed as transceivers, and wherein the frequency range is tested and at least one resonant frequency is confirmed.

12. The downhole information transmission system according to claim 1, wherein, The information signal receiver (20) is connected to one or more perforation units (70, 70a, 70b, 70c) in the wellbore, wherein the torsional wave information signal includes an ignition signal for detonating an ignition unit or detonating one of the ignition units.

13. The downhole information transmission system according to claim 1, wherein, The slender pipe (14) is made of metal.

14. The downhole information transmission system according to claim 1, wherein, At least one information signal receiver (20) includes an energy storage device (92) for supplying electrical energy to the information signal receiver (20).

15. An information signal generator (40) used in a downhole information transmission system according to any one of claims 1 to 14 and transmitting information signals along an elongated conduit (14), The information signal generator (40) is configured to be arranged outside the elongated pipe (14). The information signal generator (40) includes at least one acoustic wave generator (44) arranged perpendicular to the elongation axis of the elongated pipe (14) for generating the torsional wave information signal. in, The torsional wave information signal includes frequencies in the range of 2kHz to 20kHz.

16. The information signal generator (40) according to claim 15, wherein the acoustic wave generator (44) comprises or is composed of one or more piezoelectric disks (46).

17. The information signal generator (40) according to claim 15, wherein, The information signal generator (40) is arranged at or near the top section of the elongated pipe (14) and / or at the top portion (10) of the elongated pipe.

18. The information signal generator (40) according to claim 15, further comprising: A circumferential portion (50), wherein at least one acoustic wave generator (44) is arranged on the circumferential portion such that the acoustic wave generator exposes the circumferential portion to at least one acoustic wave, and the circumferential portion transmits the at least one acoustic wave to the elongated pipe (14).

19. The information signal generator (40) according to claim 18, wherein, The circumferential portion (50) converts the at least one sound wave emitted by the sound wave generator (44) into at least one torsional wave.

20. The information signal generator (40) according to claim 18, wherein the circumferential portion (50) includes an inner side facing the elongated conduit (14) when installed, and The circumferentially contracted portion (42) on the inner side.

21. The information signal generator (40) according to claim 18, wherein, The circumferential portion (50) is mounted to the elongated pipe (14) to form good surface contact, thereby improving signal propagation by increasing the contact pressure of the circumferential portion on the elongated pipe.

22. The information signal generator (40) according to claim 15, wherein, The acoustic wave generator (44) includes a stack of piezoelectric disks (46), and / or The sound wave generator includes an end block (48) disposed on the top of the sound wave generator, and / or The information signal generator (40) includes two acoustic wave generators (44) arranged opposite to each other, and / or The information signal generator (40) includes a plurality of acoustic wave generators (44) arranged at equal angles to each other, and / or The information signal generator (40) includes at least two acoustic wave generators (44) distributed along the elongation axis of the elongated pipe (14) such that each acoustic wave generator is capable of amplifying the torsional wave information signal.

23. An information signal receiver (20) used in a downhole information transmission system according to any one of claims 1 to 14, and receiving a torsional wave information signal propagating along an elongated conduit (14), the information signal receiver comprising: At least one transducer device (44) is designed to receive the torsional wave information signal and convert the received torsional wave information signal, the transducer device being disposed at or near the elongated pipe (14) and extending perpendicularly to the elongation axis of the elongated pipe. The outer casing (28) is shaped into an elongated or tubular form to fit into a wellbore or elongated pipe. The torsional wave information signal includes frequencies in the range of 2kHz to 20kHz.

24. The information signal receiver (20) according to claim 23. It also includes at least a second transducer device arranged opposite to the transducer device, and / or The transducer device or the second transducer device includes one or more acoustic wave receivers, wherein... The one or more acoustic receivers are piezoelectric plates.

25. The information signal receiver (20) according to claim 23. It also includes an internal transducer mounting device (30), wherein at least one transducer device (44) is mounted on the internal transducer mounting device facing the housing (28) of the information signal receiver (20).

26. The information signal receiver (20) according to claim 24. Each of the at least one transducer devices includes an end block (48) between the at least one acoustic receiver and the housing (28), one side of the end block being in contact with the acoustic receiver and the other side of the end block being in contact with the inner side (32) of the housing (28).

27. The information signal receiver (20) according to claim 23 further comprises: Independent power supply (92), which is used to store electrical energy, and / or Electronic device compartment (34), which includes analog-to-digital converter (80).

28. The information signal receiver (20) according to claim 23. It also includes a connector (18) that mounts the information signal receiver (20) to the elongated pipe (14) and / or to a continuous compartment containing explosives (70).

29. The information signal receiver (20) according to claim 23. The information signal receiver (20) also includes a sensor device (60).

30. The information signal receiver (20) according to claim 24. The at least one transducer device includes a stack of piezoelectric plates serving as the acoustic wave receiver, and / or The information signal receiver (20) is designed as a transceiver that can receive and transmit torsional waves on the elongated pipe (14) using the acoustic receiver of the information signal receiver.

31. The information signal receiver (20) according to claim 23. in, The transducer device is designed to harvest energy from the fluid motion of the well fluid (16) flowing through the elongated conduit (14).

32. A perforating gun for use in a downhole environment, the perforating gun being used in conjunction with a downhole information transmission system as defined in any one of claims 1 to 14, the downhole information transmission system comprising an information signal receiver (20) as defined in any one of claims 23 to 31.

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