Inspecting pipelines

Abstract

A Pipeline Inspection Gadget (PIG) configured to be inserted within a gas pipeline. The PIG includes a first ultrasonic transducer array arranged at a first angle relative to a central axis of the PIG and a second ultrasonic transducer is array arranged at a second angle relative to the central axis of the PIG. The second angle is different from the first angle. Each transducer array is statically arranged to emit a bulk wave at a single insonification angle. A controller is coupled to the each of the transducer arrays, a pressure sensor, and a temperature sensor. A speed of sound of the gas within the pipeline can then be determined based on the determined pressure and temperature. Using the speed of sound, an insonification angle of the first bulk wave, the second, bulk wave, or the third bulk wave are determined.

Description

INSPECTING PIPELINESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US Provisional Application 63 / 745,168, entitled “INSPECTING PIPELINES”, and filed on 14 January 2025, the entirety of which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The subject matter described herein relates to crack and metal loss pipeline inspection using bulk waves excited by a gas coupled ultrasonic transducer.BACKGROUND

[0003] Pipeline Inspection Gadgets (PIG) can be deployed in various industrial settings to assess the operational integrity of various structures. PIG systems can employ sensors to detect abnormalities within a pipeline. Such inspections occur regularly to ensure structural integrity of a given pipeline.SUMMARY

[0004] An example implementation of the subject matter described within this disclosure is a Pipeline Inspection Gadget (PIG) configured to be inserted within a gas pipeline. That is, an environment within the pipeline is a gaseous medium. The PIG includes the following features. A first ultrasonic transducer array arranged at a first angle relative to a central axis of the PIG. A second ultrasonic transducer is array arranged at a second angle relative to the central axis of the PIG. The second angle is different from the first angle. In some implementations, the PIG furtherincludes a third ultrasonic transducer array arranged at third angle relative to the central axis of the PIG. In such implementations, the third ultrasonic transducer array is configured to generate a third bulk wave at a third angle that is different from the first angle and the second angle. A range of insonification angles capable of being produced extends through about 0° to about 4.5°, and each transducer array is statically arranged to emit a bulk wave at a single insonification angle.

[0005] A controller is coupled to the each of the transducer arrays, a pressure sensor, a reference sensor, and a temperature sensor. In some implementations, the pressure sensor, the temperature sensor, and or each of the arrays is attached to the PIG. The controller is configured to perform all or some of the following actions. At least one signal indicative of an operational pressure of the gas within the PIG is received from the pressure sensor. An operational pressure for the gas within the pipeline is determined based on the at least one signal indicative of the operational pressure. At least one signal indicative of an operational temperature of the gas within the pipeline receive from the temperature sensor. An operational temperature for the gas within the PIG is determined based at least in part on the at least one signal indicative of the operational temperature. A speed of sound of the gas within the pipeline can then be determined based on the determined pressure and temperature. Using the speed of sound, an insonification angle of the first bulk wave, the second, bulk wave, or the third bulk wave are determined. In other words, the insonification angle of any of the bulk waves can be based on, at least in part, the determined operational pressure and the determined operational temperature. Alternatively or in addition, in some implementations, the controller is coupled to a reference sensor capable of measuring the speed of sound of the gas within the pipeline. In such implementations, the controller is configured to receive, from the reference sensor, at least one signal indicative of a speed of sound of the gaswithin the pipeline. The controller then determines an insonification angle of the first bulk wave, the second, bulk wave, or the third bulk wave based on the determined speed of sound.

[0006] Instructions are sent to the first ultrasonic transducer array to emit a first bulk wave towards an interior surface of the pipeline. First instructions to emit a first bulk wave towards an inner surface of the pipeline and receive a first reflected bulk wave from the inner surface of the pipeline, are received by the first ultrasonic transducer array. The first bulk wave propagating at a first insonification angle is produced by the first ultrasonic transducer array. A first reflected bulk wave is received by the first ultrasonic transducer array. A first signal representing a first reflected bulk wave is received, for example, by the controller. Instructions are sent to the second ultrasonic transducer array to emit a second bulk wave towards the interior surface of a pipeline. Second instructions to emit a second bulk wave towards an inner surface of the pipeline and receive a second reflected bulk wave from the inner surface of the pipeline are received by the second ultrasonic transducer array within the pipeline. The second bulk wave, propagating at a second insonification angle, is produced by the second ultrasonic transducer array. The second reflected bulk wave is then received by the second ultrasonic transducer array. A second signal representing the second reflected bulk wave is transmitted by the second ultrasonic transducer array. The second signal representing a second reflected bulk wave is received for example, by the controller. A presence of a discontinuity within a wall of the pipeline is determined based on the first signal or second signal, for example, by the controller. The controller is further configured to determine a first time delay based upon the first signal and a second time delay based on the second signal. For example, such a time delay can be determined using a difference between a timestamp of the first or second instructions and a timestamp of the first or second signal, respectively. The presence, size, and location of a discontinuity can then be determined based on the first time delayor the second time delay in combination with the amplitude of the first signal or the second signal. Data characterizing the discontinuity can then be provided based on this information. For example, the data can include an image.

[0007] In some instances, third instructions to emit a third bulk wave towards the inner surface of the pipeline and receive a third reflected bulk wave from the inner surface of the pipeline are received by a third ultrasonic transducer array within the pipeline. In such instances, the third bulk wave, propagating at a third insonification angle, is produced by the third ultrasonic transducer array. A third reflected bulk wave is then received by the third ultrasonic transducer array. A third signal, representing the third reflected bulk wave, is transmitted by the third ultrasonic transducer array. The third signal is then received by the controller, which is coupled to the third transducer array.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, show certain aspects of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations.

[0009] FIG. 1A is a schematic diagram of an example Pipeline Inspection Gadget (PIG)system configured to determine a discontinuity within a gas pipeline;

[0010] FIG. IB is a perspective view of an example reference ultrasonic transducer of the PIG system of FIG. 1;

[0011] FIG. 1 C illustrates an ultrasonic transducer emitting a bulk wave towards an interior surface of a gas pipeline;

[0012] FIG. ID illustrates an ultrasonic transducer arranged at an angle and emitting a bulk wave towards an interior surface of a gas pipeline;

[0013] FIG. 2A illustrates an ultrasonic transducer of an ultrasonic transducer array receiving a signal of a reflected bulk wave;

[0014] FIG. 2B illustrates a graph showing crack detection in the gas pipeline;

[0015] FIG. 3 is a flowchart of an example method that can be used with aspects of this disclosure.

[0016] FIG. 4 is a block diagram of an example controller that can be used with aspects of this disclosure.DETAILED DESCRIPTION

[0017] Certain implementations will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these implementations are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting implementations and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one implementation may be combined with the features of other implementations. Such modifications and variations are intended to be included within the scope of the present invention.

[0018] Further, in the present disclosure, like-named components of the implementations generally have similar features, and thus within a particular implementation each feature of each like-named component is not necessarily fully elaborated upon. Additionally, to the extent thatlinear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. A person skilled in the art will recognize that an equivalent to such linear and circular dimensions can easily be determined for any geometric shape. Sizes and shapes of the systems and devices, and the components thereof, can depend at least on the anatomy of the subject in which the systems and devices will be used, the size and shape of components with which the systems and devices will be used, and the methods and procedures in which the systems and devices will be used.

[0019] Pipeline inspection gadgets (PIGs) can be configured in various industrial settings to evaluate the operational integrity of a pipeline. In some instances, to determine the operational integrity of a pipeline, a PIG with an array of ultrasonic transducers is used to send ultrasonic waves through the pipeline material. Such waves can be used to find flaws such as corrosion, cracks, and wall thinning. For example, the transducers detect reflected and / or bulk waves, allowing for analysis of the pipeline's condition. During inspection, the medium in which the ultrasonic waves travel through plays an important role. For example, a pipeline with a liquid medium generally requires ultrasonic waves generated from transducers in order to operate effectively in environments with high temperature liquid or gel. In a pipeline where there is a gaseous medium, emitting ultrasonic waves from the transducers can be more difficult than in a liquid filled pipeline due to the higher acoustic impedance created by a gaseous medium. In addition to the higher acoustic impedance, variations of temperature and pressure experienced during pipeline operation can lead to variations in sound velocity. As a result, a system more sensitive than those typically used for pipelines with a liquid medium is needed.

[0020] A system for using ultrasonic transducers to detect and / or determine minor deviations within a gas pipeline is provided herein. The system includes a series of ultrasonic transducer arrays configured to emit bulk waves from within the pipeline and through a gaseous medium within the pipeline in order to detect the structural integrity of the pipeline wall. Each of the ultrasonic transducer arrays is communicatively coupled to a controller. In addition, reference, pressure, and temperature sensors are coupled to the controller and provide for constant monitoring of the temperature and pressure and a sound velocity of the gaseous medium. These measured properties are used to calculate a sound velocity of the gaseous medium within the pipeline. Given the high variability of the gaseous medium, the ultrasonic transducer arrays are arranged to include different angles of insonification to ensure that all areas of the pipeline surface are inspected accurately. In some implementations, the reference, pressure, and temperature sensors are used to provide feedback on the operating environment to the controller, and the controller can select one ultrasonic transducer array arranged at a specified angle of insonification over other ultrasonic transducer arrays to ensure that the inspection data remains accurate. In some implementations, all ultrasonic transducer arrays on the PIG can record and measure data and the data can be processed offline. For example, one ultrasonic transducer array may record more accurate data at a certain angle of insonification and, therefore, that data may be preferable to look at over the data recorded by the other ultrasonic transducer arrays. Alternatively or in addition, the provided system allows for constant monitoring of the speed of sound of the gas within the pipeline to ensure that any necessary correction is provided to the controller to select a specific ultrasonic transducer array. The angle of the selected array allows inspection data remains accurate within the variable gaseous medium. The system described herein allows for more robust inspections compared to systemsdesigned for liquid mediums by using high-frequency bulk waves which allow for direct wall thickness measurement for example, up to 51 millimeters (mm) thick.

[0021] FIG. 1 A is a schematic diagram illustrating a PIG 105 that has been inserted within a pipeline 100. The PIG 105 includes a first ultrasonic transducer array 110 arranged at a first angle relative to a central axis 115 of the PIG 105. The first ultrasonic transducer array 110 is communicatively coupled to the controller 125, and the controller 125 is configured to instruct the first ultrasonic transducer array 110 to emit a bulk wave towards the interior surface of the pipeline 100. In some implementations, the environment within the pipeline includes a gaseous medium 128. The first ultrasonic transducer array 110 is arranged and configured to emit a bulk wave through the gaseous medium 128 towards the interior surface of the pipeline 100. In some implementations, the controller 125 is communicatively coupled to a second ultrasonic transducer array 120. In such implementations, the controller 125 is configured to instruct the second ultrasonic transducer array 120 to emit a bulk wave towards the interior surface of the pipeline 100. The second ultrasonic transducer array 120 can be arranged at an angle different than the first ultrasonic transducer array 110. For example, the first ultrasonic transducer array 110 can be arranged perpendicular to the central axis 115 of the PIG 105 and, therefore, can emit a bulk wave perpendicular to and towards an inner surface of the pipeline 100. Similarly, the second ultrasonic transducer array 120 can be arranged at an angle different from the angle of the first ultrasonic transducer array 110, for example, 4.5° from perpendicular to the central axis 115 of the PIG 105. The different potential angles of insonifi cation allow for an angle to be selected that will best ensure that a bulk wave penetrates and propagates along the wall of the pipeline 100. In some implementations, the angle of the ultrasonic transducer arrays can be within a range of about 0°through about 4.5° (+ / - 1°), from perpendicular to the central axis 115 of the PIG 105, when emitting a bulk wave towards the interior surface of the pipeline.

[0022] As previously described, the ultrasonic transducer arrays can be arranged within a range of 0° through about 4.5° (+ / - 1°) from perpendicular to the central axis 115. In addition, the ultrasonic transducer arrays can include a sensor arranged at 0° to perform a wall thickness measurement on the pipeline 100. For example, as shown in FIG. 1C, the first ultrasonic transducer array 110 can include a sensor 110A which can be configured to emit a bulk wave at 90° relative to the central axis 115. Throughout the inspection process, the sensor 100A can continuously emit bulk waves toward the wall of the pipeline 100 to monitor the structural integrity of the pipeline wall at multiple points. For instance, the pipeline wall may experience corrosion or may be thinning, which can be detected and / or measured by the sensor 100A.

[0023] In some implementations, a reference sensor 142 (FIG. IB) is arranged and configured to continuously (e.g., constantly or at a set frequency) monitor a speed of sound of the gaseous medium 128. For instance, the reference sensor 142 can emit first bulk wave at a first known time and can receive the bulk wave at second time after the bulk wave has been reflected from a reflector plate 144. The reference sensor 142 can be used determine the time delay between the emitted and received bulk wave. This time delay can be used, by the controller for example, to determine the speed of sound of the gaseous medium within the pipeline 100 in substantially real time (e.g., on the order of seconds).

[0024] The reference sensor 142 can be attached to the PIG 105 and can emit a bulk wave 148 towards a reflector plate 144. The reflector plate 144 is a fixed distance from the reference sensor 142, for example, within the range of 10 to 20 millimeters (mm). As the reference sensor 142 emits the bulk wave 148, the reflector plate can receive the emitted bulk wave 148 from thesensor 142, then reflects the bulk wave 148 back to the sensor 142. Once the sensor 142 receives the reflected bulk wave 148, the controller 125 can determine the time it took receive the emitted bulk wave. Then, using the time duration, the controller 125 can determine the speed of sound in the pipeline 100.

[0025] As shown in FIGS. IB - ID, the first ultrasonic transducer array 110, and the second ultrasonic transducer array 120 can be arranged around the central axis 115 of the PIG 105. Each transducer of the first ultrasonic transducer array 110 and the second ultrasonic transducer array 120 are configured and arranged to emit bulk waves towards an interior surface of the pipeline (not shown) and travel axially within a wall of the pipeline. As the bulk waves travel through the pipeline, the bulk waves can be reflected and subsequently received by at least one ultrasonic transducer array. For example, as shown in FIG. 1C, a single transducer 110A of the first ultrasonic transducer array 110 can emit a first bulk wave 111 towards the surface of the pipeline 100. As the first bulk wave 111 travels through the interior surface of the pipeline 100, the first bulk wave 111 can be reflected by an outer surface of the pipeline 100 and can be received by the single ultrasonic transducer 110A as a first signal 112. Such an operation can be used to measure a thickness of the wall of the pipeline, for example, to determine a corrosion rate of the pipeline. Alternatively or in addition, as a distance from the transducer 110A and an interior surface of the pipeline 100 is known (based on the pipe schedule of the pipeline), such an arrangement can be used to measure the speed of sound of the gas within the pipeline 100. In such implementations, a statistical average of such readings can be used as an interior and / or exterior surface of the pipeline 100 can include isolated areas of material loss due to corrosion or erosion. In some instances, the first signal 112 can be difficult to detect due to the attenuation caused by the low density of gas compared to other mediums (e.g., liquids, gels, multiphase flow, and / or suspensions)found within pipelines. To mitigate such attenuation, the first ultrasonic transducer array 110 can include multiple ultrasonic transducers to provide for constant monitoring of the reflected bulk waves emitted from the ultrasonic transducer arrays and reflected from the pipeline 100.

[0026] As previously described, the first bulk wave 111 can be reflected towards the first ultrasonic transducer 110A of the first ultrasonic transducer array 110. As the first bulk wave 111 travels, the controller 125 can then measure the time it takes for the first signal 112 to travel back to the first ultrasonic transducer 110A, for example, by determining a difference between a timestamp characterizing when the first bulk wave was emitted and a timestamp indicating when the first signal 112 is received. The measured time delay can indicate where the discontinuity is along the surface of the pipeline 100. For instance, a short time delay between the first bulk wave 111 and the first signal 112 may be indicative of a thickness of the wall of the pipeline 100.

[0027] Alternatively or in addition, in some instances, the controller 125 can measure the first bulk wave 111 in terms of the sound it generates as it propagates through the interior surface of the pipeline 100. As previously described, the PIG 105 includes a pressure sensor 150 and a temperature sensor 140 attached to the PIG 105. The pressure sensor 150 and the temperature sensor 140 are configured to produce signals and / or data indicative or characterizing the pressure and temperature within the pipeline (FIG. 1 A). For example, the controller 125 can receive at least one signal from each of the pressure sensor 150 and temperature sensor 140, and, based on each signal, the controller 125 can determine a current operational pressure and temperature at a specific location in the pipeline. The controller 125 can also receive information, via an operator of the PIG 105, about a density of the gas within the pipeline 100. The controller can then use the density and to calculate the speed of sound of the gas at a specific point along the pipeline 100. In some implementations, the controller 125 can be configured to constantly (e.g. continuous, real-time,periodic and / or at some frequency) calculate the speed of sound within the pipeline 100. With such information, the controller 125 is configured to select an ultrasonic transducer array based on the determined speed of sound at a given location. In some instances, the controller 125 is configured to compare the calculated speed of sound determined from signals provided by the pressure and temperature sensors against the speed of sound determined by the reference sensor 142. For instance, the controller 125 can receive a first calculated speed of sound from the reference sensor 142A and can receive a second calculated speed of sound based on the pressure sensor 150 and temperature sensor 140 on the first ultrasonic transducer array 110. The first and second calculated speed of sound can be different from one another, and the controller can determine, using a threshold, which calculated speed of sound is more accurate. For example, if the calculated speed of sound of the pressure sensor 150 and temperature sensor 140 differs from the calculated speed of sound of the reference sensor 142 by more than 10%, the controller can then determine that one or both sensors is providing an inaccurate reading.

[0028] In some instances, the received information from the pressure sensor 150 and temperature sensors 140 may indicate that the operational pressure and temperature within the pipeline 100 is outside of an optimal operating range for a given ultrasonic transducer array. For example, the first ultrasonic transducer array 110 can be configured to operate more accurately, compared to ultrasonic transducer array 120, within a pressure range of 1 to 50 bar and a temperature range of -40° to 20° Celsius (C). If the received information about the operational pressure and temperature is outside of the above-mentioned range, the controller 125 can choose to emit a bulk wave from the second ultrasonic transducer array 120. Similarly, the second ultrasonic transducer array 120 can be configured to operate more accurately, compared to ultrasonic transducer array 110, within a pressure range of 50 to 130 bar and a temperature rangeof 20° to 70° Celsius (C). Thus, if the received information about the operational pressure and temperature is outside of the above-mentioned range, the controller 125 can choose to emit a bulk wave from the first ultrasonic transducer array 110. In some implementations, the controller 125 determines, based on the operating conditions, which array to emit a bulk wave from in order to a produce a 45° bulk wave within the wall of the pipeline 100. For instance, the controller 125 can determine, based on the operating conditions, that the first ultrasonic transducer array would not be able to produce a bulk wave within the wall of the pipeline 100 at 45° and can then select the second ultrasonic transducer array, or vice versa.

[0029] As described above, the controller can receive information regarding the density of the gaseous medium from a user and can then, using the density and the received information from the pressure sensor 150 and temperature sensor 140, calculate the speed of sound within the pipeline 100. Furthermore, the controller 125 can determine a time delay between the first bulk wave 111 and the first signal 112 using the time at which the first bulkwave Ill is emitted from the first ultrasonic transducer 110A and the time at which the first signal 112 is received by the first ultrasonic transducer 110A. An amplitude of the first signal 112 can also be determined based on the first signal 112. The received first signal 112 can indicate that there is a discontinuity in the wall of the pipeline 100 and, based at least in part on the amplitude and time delay, a size and a location of the discontinuity can be determined.

[0030] Furthermore, in relation to FIG. 1A, the controller 125 and can determine the size of the discontinuity based on the amplitude and the time delay of the first signal 112 and the calculated speed of sound within the pipeline 100. Also, the controller can determine and command the second ultrasonic array 120 to emit a bulk wave over the first ultrasonic transducer array 110. As a result, the second ultrasonic transducer 120A can emit a second bulk wave 121towards an interior surface of the pipeline 100. As previously discussed, the second ultrasonic transducer 120A can be arranged at an angle different from the first ultrasonic transducer 110A. If a discontinuity is present in the surface of the pipeline 100, the controller 125 can receive a second signal 122 representing the reflected bulk wave 121. For example, as shown in FIG. ID, the second ultrasonic transducer 120A can be arranged at the angle 0i relative to the central axis 115 of the pipeline. In some implementations, Oi can be between 0° and 4.5° from perpendicular relative to the wall of the pipeline 100, which can then produce a 20°, 30°, or 45° signal relative to the central axis 115 of the pipeline 100 depending upon the density of the gas within the pipeline 100. For example, the angle 0i can represent the insonification angle of the ultrasonic transducer array 120 and can produce a bulk wave of 45°, relative to the central axis 115, within the wall of the pipeline 100. Furthermore, as shown in FIG. ID, the second ultrasonic transducer 120A can receive a second signal 122 reflected off the crack 124 within the wall of the pipeline 100. Without the crack 124 present, the second bulk wave 121 would continue to propagate through the wall of the pipeline 100. The controller 125 can use the time stamp of the emitted bulk wave 121 and the time stamp of the received signal 122 to determine a time delay of the reflected signal 122 characterizing the crack 124 in the surface of the pipeline 100.

[0031] FIGS. 2A-2B illustrate an implementation of one ultrasonic transducer 220A of an ultrasonic transducer array configured to determine the presence of discontinuity within a pipeline 200. The time delay measured between the emitted bulk wave and the reflected signal changes depending on a size, type, and distance or a discontinuity from the transducer array. As shown in FIG. 2A, the ultrasonic transducer 220A can emit a bulk wave 221 toward the interior surface of the pipeline 200. As the first bulk wave 221 propagates throughout the interior surface of the pipeline 200, the bulk wave 221 can reflect between an inner and an outer surface of the pipeline200 and propagate in a direction confined by an inner and outer surface of the pipeline 200. The ultrasonic transducer 220A can also receive a signal 222 representing a reflected bulk wave, and then determine the size and location of a discontinuity in the pipeline surface based at least in part on the amplitude, time delay of the received signal 222, and the calculated speed of sound of the gaseous medium 228. In some implementations, the ultrasonic transducer 220A perform this process by emitting multiple bulk waves from the transducer 220A to the interior surface of the pipeline 200 over a predefined period. When the ultrasonic transducer 220A receives the signal 222 representing the discontinuity, the ultrasonic transducer 220A can then send a signal representing the size of the discontinuity to the controller 229 communicatively coupled to the ultrasonic transducer array 220. The controller 229 can determine the size of the discontinuity based on the amplitude of that signal while the location of that discontinuity can be determined based on the time delay. Over time, the controller 229 can compile the signals received by each of the ultrasonic transducers of the first ultrasonic transducer array 110 and the second ultrasonic transducer array 120 to provide an image indicating the presence of a discontinuity in the wall of the pipeline. For example, as shown and FIG. 2B, an image displaying a graph 250 can be produced and displayed on an interactive display communicatively coupled to the PIG inserted within the pipeline. In some implementations, the graph can be displayed for viewing by a user of the PIG system. The graph can include the signal 226 representing a discontinuity detected in the interior surface of the pipeline during inspection.

[0032] As described above, the controller 229 can receive a signal representing the reflected bulk wave. Over a period of time, the controller compiles these signals and can create an image for display to the operator of the PIG. For example, as shown in FIG. 2B, the graph 250 can represent a period of inspection performed by the PIG system described above. As describedabove, the PIG system can perform a method to determine a certain pressure and temperature for operating the PIG during inspection. For example, the temperature and pressure within the pipeline can impact the ability of the ultrasonic transducers to function properly during inspection. So, as described above in relation to FIGS. 1A-1D, the controller can be coupled to at least one pressure sensor and at least one temperature sensor. The controller can be configured to receive at least one signal representing the operating pressure within the gaseous medium of the pipeline. Similarly, the controller can be configured to receive at least one signal representing the operating temperature within the gaseous medium of the pipeline. In some implementations, the controller can determine how much the pressure and temperature are fluctuating in the pipeline and can then determine, based on the at least one signal representing the pressure or temperature, a maximum and a minimum operational pressure and temperature. For example, as shown in FIG. 2B, the controller can receive a series of signals 245 that indicate a disturbance within the pipeline. The disturbance can be caused by an abnormal pressure or temperature experienced by the ultrasonic transducer arrays during inspection of the pipeline.

[0033] When the ultrasonic transducer arrays experience an abnormal pressure or temperature, they can communicate this to the controller and the controller can further determine an operational pressure or temperature suitable for the ultrasonic transducers on the ultrasonic transducer arrays. Similarly, the controller can also decide to use an ultrasonic transducer array arranged at a specific insonification angle based on the received signals from the pressure and temperature sensors. Due to the high sensitivity of ultrasonic transducers in a gaseous medium, the choice to use one ultrasonic transducer array at a certain insonification angle may need to change in order to better detect a discontinuity within the pipeline. For instance, as described above, the ultrasonic transducers determine both a minimum and a maximum operational temperature andpressure based on the signal received from each of the pressure and temperature sensors. If the pressure or temperature sensors receive signals indicating abnormal pressure or temperature, as shown by signals 245, the controller can then determine an average operational pressure and temperature that is suitable for the ultrasonic transducers to operate in. As a result, the controller may determine that a third ultrasonic transducer array is better to use for inspection over the first or second ultrasonic transducer arrays based on the average operational pressure and temperature. The controller can also determine, based on the received temperature and pressure signals, that the insonifi cation angle of the third ultrasonic transducer array is best to emit bulk waves at so that the inspection process is not interrupted. In some implementations, the controller can alert a user of the PIG that the pressure or temperature is out of the average range and can provide recommendations to the user to adjust which ultrasonic transducer array is being used.

[0034] FIG. 3 is a flowchart of an example method 300 according to some example implementations. Aspects of the method 300 can be performed by the controller and ultrasonic transducer arrays all or in part. At 310 a first ultrasonic transducer array within a pipeline receives first instructions to emit a first bulk wave towards an inner surface of the pipeline. The pipeline includes a gaseous medium and the instructions can be sent to the ultrasonic transducer array from a controller communicatively coupled to the ultrasonic transducer array. In some implementations, the first ultrasonic transducer array can be arranged at an angle relative to the central axis of the pipeline. For instance, the angle can be in the range of about 0° to about 4.5° (+ / - 5°) and the first ultrasonic transducer can produce a bulk wave at this angle. Once the first ultrasonic transducer emits the bulk wave, the bulk wave can propagate through a wall of the pipeline and can, in some instances, be received back at the first ultrasonic transducer array.

[0035] The first ultrasonic transducer array 110 can then transmit a first signal representing the reflected bulk wave, and, at 320, a controller receives the first signal representing the reflected bulk wave. The first ultrasonic transducer array can receive the bulk wave in the form of a signal indicating the size and location of the discontinuity. The size and location of the bulk wave can be determined based on the time delay between the emitted bulk wave and the received signal. The received signal can represent the presence of a discontinuity in the surface of the pipeline and the size of the discontinuity can be characterized by the amplitude of that signal.

[0036] At 330, second instructions are received to emit a second bulk wave towards an inner surface of the pipeline by a second ultrasonic transducer array within a pipeline. The instructions can instruct the second ultrasonic transducer array that has been arranged at an angle relative to the central axis of the pipeline. The angle of the second ultrasonic transducer array is different from the angle of the first ultrasonic transducer array. For instance, the angle can be in the range of 4.5° to 9.5° and the second ultrasonic transducer can produce a bulk wave at this angle. The second ultrasonic transducer can emit the bulk wave and the bulk wave can propagate through the pipeline and can be received back at the second ultrasonic transducer array if a discontinuity is present in the surface of the pipeline. In some instances, the second ultrasonic transducer array 120 can then transmit a second signal representing a second reflected bulk wave, and, at 340, the controller receives the second signal representing the second reflected bulk wave.

[0037] In some instances, at 350, the size and location of a discontinuity in the pipeline are determined based on the first signal representing the first reflected bulk waves. For example, the controller can determine a time delay based on the received signal of the first reflected bulk wave. Based on the time delay, the controller can determine a point along the pipeline where the discontinuity is likely to be located. In some implementations, the PIG can employ a thirdultrasonic transducer array to emit a third bulk wave at an insonifi cation angle that is different from the first ultrasonic transducer array and the second ultrasonic transducer array. The third ultrasonic transducer array is configured to receive a third signal representing the reflected bulk wave and can send this signal to the controller for further analysis. In such instances, the controller then determines the amplitude and time delay based on a third received signal to determine a size and a location of a discontinuity in the surface of the pipeline. In some implementations, the third ultrasonic transducer array can be used by the PIG system determine a discontinuity.

[0038] Alternatively, or in addition, in some instances, the size and location of the discontinuity can be determined separate from the controller 125. In one aspect, the data measured by the ultrasonic transducer arrays can be sent to a server offline and can be further analyzed to determine the characteristics of a discontinuity. For instance, and as previously described with respect to operational pressure and temperature, the calculated speed of sound of the reference sensor and the pressure and temperature sensors is important for determining which ultrasonic transducer array to use during inspection. In some implementations, the controller can determine whether to use the calculated speed of sound of the reference sensor or the pressure and temperature sensors in real-time during inspection. In this aspect, the controller can also determine which ultrasonic transducer array to use based on the most accurate calculated speed of sound. In some implementations, using the controller to make a determination on which speed of sound and which ultrasonic transducer to use can be time-consuming. As a result, the controller can continuously monitor the pressure, temperature and calculated speed of sound during inspection and can send the measured data back to a server offline to be analyzed. For example, the operator of the PIG can assess, based off of the received temperature, pressure, and calculated speed ofsound, which ultrasonic transducer array is best fit to determine the presence of a discontinuity in the surface of the pipeline.

[0039] FIG. 4 illustrates an example controller 125 that can be used with some aspects of the current subject matter. The controller 125 can, among other things, monitor parameters of the system 100 send signals to actuate and / or adjust various operating parameters of the system 100. As shown in FIG. 4, the controller 125 can include one or more processors 450 and non-transitory, computer readable memory storage (e.g., memory 452) containing instructions that cause the processors 450 to perform operations. The processors 450 are coupled to an input / output (I / O) interface 454 for sending and receiving communications with components in the system, including, for example, the pressure sensor 150, the temperature sensor 150, the the first transducer array 110, and / or the second transducer array 120. In certain instances, the controller 125 can additionally communicate status with and send actuation and / or control signals to one or more of the various system components (including, for example, a a specified transducer array) of the system 100, as well as other sensors (e g., vibration sensors, position sensors, and other types of sensors) that provide signals to the system 100.

[0040] The controller 125 can be implemented with various levels of autonomy. In some implementations, the controller 125 alerts an operator of a present speed of sound within the pipeline, and the operator then selects a transducer array that best works with the present speed of sound. In some implementations, the controller 125 alerts the operator of a present speed of sound within the pipeline,, and provides a recommended transducer array to use with the present speed of sound. The operator then selects an option and the controller 125 adjusts operations accordingly. In some instances, the controller 125 determines a present speed of sound within the pipeline,, and selects an appropriate transducer for the present speed of sound without input froman operator. Alternatively or in addition, the controller can record data from all sensors and transducers so that the data can be fully analyzed after the PIG 105 has passed through the pipeline 100.

[0041] While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0042] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

[0043] Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, theprocesses depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results.

[0044] ... Other implementations can be within the scope of the following claims.

Claims

What is claimed:

1. A Pipeline Inspection Gadget (PIG) configured to be inserted within a pipeline, the PIG comprising:a first ultrasonic transducer array arranged at a first angle relative to a central axis of the PIG;a second ultrasonic transducer array arranged at a second angle relative to the central axis of the PIG, the second angle being different from the first angle;a controller coupled to the first ultrasonic transducer array, wherein the controller is configured to:send instructions to the first ultrasonic transducer array to emit a first bulk wave towards an interior surface of the pipeline, wherein an environment within the pipeline is a gaseous medium;receive a first signal representing a first reflected bulk wave;send instructions to the second ultrasonic transducer array to emit a second bulk wave towards the interior surface of a pipeline;receive a second signal representing a second reflected bulk wave; and determine a presence of a discontinuity within a wall of the pipeline based on the first signal or second signal.

2. The PIG of claim 1, wherein the controller is further configured to determine a first time delay based upon the first signal.

3. The PIG of claim 2, wherein the controller is further configured to determine a second time delay based on the second signal.

4. The PIG of claim 1, wherein the controller is further configured to determine a size of a discontinuity based on the received signals representing the reflected bulk waves.

5. The PTG of claim 1 , wherein the PIG further comprises a third ultrasonic transducer array arranged at third angle relative to the central axis of the PIG, wherein the third ultrasonic transducer array is configured to generate a third bulk wave, the third angle being different from the first angle and the second angle.

6. The PIG of claim 5, wherein an insonification angle propagated by the first bulk wave, the second bulk wave, or the third bulk wave, extends through a range of about 0° to about 4.5°.

7. The PIG of claim 5, wherein the controller is communicably coupled to at least one pressure sensor, wherein the controller is further configured to:receive, from the pressure sensor, at least one signal indicative of an operational pressure of the gas within the pipeline; anddetermine, based on the at least one signal indicative of the operational pressure, an operational pressure for the gas within the pipeline.

8. The PIG of claim 7, wherein the controller is communicably coupled to at least one temperature sensor, wherein the controller is further configured to:receive, from the temperature sensor, at least one signal indicative of an operational temperature of the gas within the pipeline; anddetermine, based at least in part on the at least one signal indicative of the operational temperature, an operational temperature for the gas within the pipeline.

9. The PIG of claim 8, wherein the controller is further configured to determine an insonification angle of the first bulk wave, the second, bulk wave, or the third bulk wave based on the determined operational pressure and the determined operational temperature.

10. The PIG of claim 9, wherein the controller is further configured to provide data characterizing the discontinuity.

11. The PTG of claim 5, wherein the controller is coupled to a reference sensor, wherein the controller is further configured to:receive, from the reference sensor, at least one signal indicative of a speed of sound of the gas within the pipeline;determine, based on the at least one signal indicative of the speed of sound, an insonifi cation angle of the first bulk wave, the second, bulk wave, or the third bulk wave.

12. A method comprising:receiving, by a first ultrasonic transducer array of a Pipeline Inspection Gadget (PIG) within a pipeline, first instructions to emit a first bulk wave towards an inner surface of the pipeline and receive a first reflected bulk wave from the inner surface of the pipeline, an environment within the pipeline being a gaseous medium;producing, by the first ultrasonic transducer array, the first bulk wave propagating at a first insonification angle;receiving, by the first ultrasonic transducer array, a first reflected bulk wave; transmitting, by the first ultrasonic transducer array, a first signal representing the first reflected bulk wave;receiving, by a controller coupled to the first ultrasonic transducer array, the first signal representing the reflected bulk wave;receiving, by a second ultrasonic transducer array within the pipeline, second instructions to emit a second bulk wave towards an inner surface of the pipeline and receive a second reflected bulk wave from the inner surface of the pipeline;producing, by the second ultrasonic transducer array, the second bulk wave propagating at a second insonification angle;receiving, by the second ultrasonic transducer array, a second reflected bulk wave; transmitting, by the second ultrasonic transducer array, a second signal representing the second reflected bulk wave;receiving, by the controller coupled to the second ultrasonic transducer array, the second signal representing the reflected bulk wave; anddetermining, by the controller, a presence of a discontinuity within the inner surface ofthe pipeline based on the first signal or second signal representing the first reflected bulk wave and second reflected bulk wave respectively.

13. The method of claim 12, further comprising determining, by the controller, a location of a discontinuity within a wall of the pipeline based upon a difference between a timestamp of the first instructions and a timestamp of the first signal.

14. The method of claim 13, further comprising determining, by the controller, a speed of sound within the gas based on a third signal indicative of a temperature within the pipeline and a fourth signal indicative pressure within the pipeline, the third signal being produced by a temperature sensor attached to the PIG, the fourth signal being produced by a pressure sensor attached to the PIG.

15. The method of claim 14, wherein determining, by the controller, a discontinuity within a wall of the pipeline based on the first signal or the second signal further comprises:determining, by the controller, a size of a discontinuity based at least in part on an amplitude of the first signal or the second signal.

16. The method of claim 12, further comprising:receiving, by a third ultrasonic transducer array within the pipeline, third instructions to emit a third bulk wave towards the inner surface of the pipeline and receive a third reflected bulk wave from the inner surface of the pipeline;producing, by the third ultrasonic transducer array, the third bulk wave propagating at a third insonification angle;receiving, by the third ultrasonic transducer array, a third reflected bulk wave; transmitting, by the third ultrasonic transducer array, a second signal representing the third reflected bulk wave; andreceiving, by the controller coupled to the ultrasonic transducer array, the third signal representing the reflected bulk wave.

17. The method of claim 16, wherein an insonification angle propagated by the first bulk wave, the second bulk wave, and extends through a range of about 0° to about 4.5°.

18. The method of claim 12, further comprising:receiving, from a pressure sensor, at least one signal indicative of an operational pressure of the gas within the pipeline; anddetermining, based on the at least one signal indicative of the operational pressure, an operational pressure for the gas within the pipeline.

19. The method of claim 18, further comprising:receiving, from a temperature sensor, at least one signal indicative of an operational temperature of the gas within the pipeline; anddetermining, based on the at least one signal indicative of the operational temperature, an operational temperature for the gas within the pipeline.

20. The method of claim 19, further comprising determining, by the controller, an insonification angle based on the determined operational pressure and the determined operational temperature.

21. The method of claim 20, further comprising providing data characterizing the discontinuity.

22. A Pipeline Inspection Gadget (PIG) configured to be inserted within a gas pipeline, the PIG comprising:a first ultrasonic transducer array arranged at a first angle relative to a central axis of the PIG;a second ultrasonic transducer array arranged at a second angle relative to the central axis of the PIG, the second angle being different from the first angle;a pressure sensor configured to sense a pressure of a gas within the pipeline; a temperature sensor configured to sense a temperature of the gas within the pipeline; and a controller coupled to the first ultrasonic transducer array, the second ultrasonic transducer array, the pressure sensor, and the temperature sensor, wherein the controller is configured to determine a presence of a discontinuity within a wall of the pipeline based on signals received from the first ultrasonic transducer array, the second ultrasonic transducer array, the pressure sensor, and the temperature sensor.

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