Acoustic Reflectometry for Blockage Detection in Pipeline

Author(s):  
L. Loureiro Silva ◽  
P. C. C. Monteiro ◽  
J. L. A. Vidal ◽  
Theodoro A. Netto

Flow assurance is an important aspect of offshore, particularly deepwater pipeline design and operation, since one of the critical issues is the eventual initiation and growth of hydrate or paraffin blockages under certain conditions. Ideally, operators would benefit from online information regarding position and extent of an eventual blockage in a pipeline. The aim of this work is to apply acoustic technology to design and make a prototype that can be used in a pipe to efficiently identify and measure blockages. The technique uses a short duration sound pulse that is injected into the pipe. When the acoustic pulse encounters an impedance discontinuity, a portion is reflected back towards the acoustic source and microphones or hydrophones. Analysis of the measured signal reflections can provide valuable data related to location and size of the blockages. An experimental setup with a pipe of 4″ internal diameter and length of 100 m was constructed, and different excitation signals for the impulsive response function measurements were conducted. Microphones and hydrophones measurements were recorded using a fit-for-purpose data acquisition system with sampling rates of up to 1kS/s per channel. The tests were performed in air and water using different sizes of blockages and in different positions in the pipe. In parallel, finite element analyses were performed using the commercial software Abaqus to simulate the same conditions. The experiments were numerically reproduced with good correlation proving the potential of the technique.

Author(s):  
Paulo Cesar da Camara Monteiro Junior ◽  
Luciana Loureiro da Silva ◽  
Theodoro Antoun Netto

Abstract Flow assurance is an important aspect of deepwater pipeline design and operation, since one of the critical issues is the eventual initiation and growth of hydrate or paraffin blockages under certain conditions. Another relevant problem is the incidence of inorganic scale deposition in oil well production tubes during operation. This work deals with experimental and numerical simulations of an acoustic system to identify and measure blockages. The technique uses a short duration acoustic pulse that is injected into the pipe. When the pulse encounters an impedance discontinuity, a portion is reflected towards the acoustic source and, depending on fluid type, microphones or hydrophones can be used to measure the signals. Analysis of the measured signal reflections can provide valuable data related to location and size of the blockages. An experimental setup with a steel pipe of 4” internal diameter and length of 100 m was developed to evaluate the suitability of the technique for gas pipelines. In parallel, finite element analyses were performed using the commercial software Abaqus to simulate the same physical parameters. The experiments were numerically reproduced with good correlation proving the potential of the technique. Subsequently, a parametric study was carried out to examine the acoustic detection capability using different blockage types. Finally, a prototype of the acoustic reflectometry detection system was developed and tested in a full-scale onshore water-filled pipeline to show the feasibility of the method for detecting blockages.


Author(s):  
M. R. Myers ◽  
D. G. Walker ◽  
D. E. Yuhas ◽  
M. J. Mutton

Ultrasonic time of flight measurements have been used to estimate the interior temperature of propulsion systems remotely. All that is needed is acoustic access to the boundary in question and a suitable model for the heat transfer along the path of the pulse train. The interior temperature is then deduced from a change in the time of flight and the temperature dependent velocity factor, which is obtained for various materials as a calibration step. Because the acoustic pulse samples the entire temperature distribution, inverse data reduction routines have been shown to provide stable and accurate estimates of the unknown temperature boundary. However, this technique is even more interesting when applied to unknown heat flux boundaries. Normally, the estimation of heat fluxes is even more susceptible to uncertainty in the measurement compared to temperature estimates. However, ultrasonic sensors can be treated as extremely high-speed calorimeters where the heat flux is directly proportional to the measured signal. Through some simple one-dimensional analyses, this work will show that heat flux is a more natural and stable quantity to estimate from ultrasonic time of flight. We have also introduced an approach for data reduction that makes use of a composite velocity factor, which is easier to measure.


Author(s):  
Noam Amir ◽  
Oded Barzelay ◽  
Amir Yefet ◽  
Tal Pechter

Acoustic Pulse Reflectometry (APR) has been applied extensively to tubular systems in research laboratories, for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of six meters in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, on the order of 20cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically, with a measurement time on the order of 10 seconds per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported.


Author(s):  
N. Amir ◽  
O. Barzelay ◽  
A. Yefet ◽  
T. Pechter

Acoustic pulse reflectometry (APR) has been applied extensively to tubular systems in research laboratories for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of 6 m in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, in the order of 20 cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically with a measurement time on the order of 10 s per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported.


2021 ◽  
Author(s):  
Guillaume Plessis ◽  
Andrei Muradov ◽  
Richard Griffin ◽  
Jeremy Dugas ◽  
Justin Orlando ◽  
...  

Abstract Drilling out or working within small sizes of casing and liners requires the use of a drill string with small outside diameter tool joints to fit inside the casing/liner bore and, at the same time, a large enough connection internal diameter to pump actuating balls inside the drill string when needed. These requirements significantly limit the available options that can be used. Historically, a drill pipe double shoulder connection with a 3⅛-in. outside diameter (OD) has been used for such operations, as it allows for multiple makeups and breakouts before it needs to be repaired. This is a great improvement compared to using small tubing premium connections that are somewhat limited on the number of makeups. However, the geometry constraints are such that the thin material envelope leads to torsional weakness in the connection, resulting in a higher than expected recut rate as connections can be overtorqued downhole in operation. A research and development (R&D) project was commissioned to improve the connection performance significantly to mitigate the downhole overtorque. Exploring the acceptable connection envelope limits allowed for a slightly reduced internal diameter (ID) when compared to the previously used connection. The team considered different thread designs and decided to use the one that would provide the highest torque. The design process was then followed to develop and qualify a well-balanced connection. The design validation was performed at an engineering technology center in Houston, Texas, where samples were destructively tested to compare the actual capacity of the new connection against the calculated values. It was confirmed that the torsional strength of the new design meets and exceeds the theoretical value, an improvement of at least 85% over the previously used connection, and a first string was built. It was subsequently deployed in the field and the recut rate was monitored to establish that the objective of delivering a connection capable of higher torque was indeed met to resist the downhole overtorque.


Author(s):  
Noam Amir ◽  
Oded Barzelay ◽  
Amir Yefet ◽  
Tal Pechter

Acoustic Pulse Reflectometry (APR) has recently been gaining acceptance for a variety of tube inspection applications, as a viable alternative to more entrenched technologies such as eddy current. In this paper we present a case study demonstrating how APR can be used successfully for inspecting U-tube bundles. This type of heat exchanger poses a great challenge to technologies which require traversal with a probe, due to the presence of tight bends in the tubes. These are usually not traversable by probes. APR, on the other hand, uses an acoustic pulse as a “virtual probe”, with the ability to navigate bends, elbows, fittings etc. with no difficulty. In this paper we show how the various typical faults are revealed in the acoustic measurements and demonstrate how the analysis software recognizes these faults and generates the report. In one case presented here we inspected 62 heat exchangers used to heat natural gas, containing 39 U-tubes each, totaling 2379 tubes. Each tube had an internal diameter of 11mm, wall thickness of 2.5mm, and a length of approximately 6 meters, though there was some variability in length due to different lengths of the U bends. An added difficulty in inspecting these tubes was that the tube sheet was about 80 centimeters in distance from the inspection port-hole. The average inspection time in the field was 25 seconds per tube. All measurements were logged to computer files, and automated fault detection software generated a full report showing the condition of the tubes, indicating degradations in wall thickness, full and partial blockages, and holes. In the second case study we examine the variability in u-tubes in a single bundle and discuss the effect this has on the results.


1967 ◽  
Vol 15 (4) ◽  
pp. 263-277 ◽  
Author(s):  
P. Chadwick ◽  
G. E. Tupholme

The generation of acoustic disturbances in a fluid of semi-infinite extent by the motion of a circular piston surrounded by a plane rigid baffle has been studied quite extensively (see (1), (2), (3), (4) and further references given in these papers). Attention has been devoted mainly to the case in which the piston executes a harmonic oscillation of small amplitude, and only comparatively recently has Oberhettinger (2) demonstrated how the time-harmonic solution can be used to solve the more general problem in which the normal velocity of the piston is an arbitrary function of time. The purpose of the present paper is two-fold. Firstly, we point out that for arbitrary normal motion of the piston the " baffled piston problem " can be solved directly, and in a particularly simple manner, by means of a technique involving integral transforms which has been applied by Mitra (5) and Eason (6) to the study of shear wave propagation in an elastic half-space. Secondly, we give a more detailed account than appears to be available in the literature of the structure of the sound pulse generated by the arbitrary normal motion of a baffled piston.


2021 ◽  
Author(s):  
Tom Emelander ◽  
Justin Muesel ◽  
Casey Carrington

Abstract After a 13 3/8-in. expandable liner collapsed in a Gulf of Mexico ultradeepwater well, an operator considered a whipstock sidetrack, exiting as deep as possible to finish drilling and completion operations. Exiting the 16-in. casing, industry standards would have called for redrilling and casing an entire hole section. Exiting the expandable liner was an alternative option, but would require a unique solution to operate in the larger internal diameter (ID) and maintain the existing hole size. The service provider created a fit-for-purpose solution to install a casing window in the 13.77-in. ID expandable liner. The standard casing exit system accommodates 13 3/8-in. casing through 14-in. casing and requires minimal modifications to anchor the actual concave assembly to support a 12.25-in. pilot window. Additional mill runs would then open the 12.25-in. pilot window to a full bore 13 1/2-in. outside diameter (OD) window. Despite never having performed an installation in this size of expandable liner, the provider had a run history for exits with similar modifications and extra trips to enlarge and elongate windows. Job challenges included thin-wall, channeled cement; limited flow rates because of liner pressure limits; equipment availability; and a short lead time. The 11 1/2-in. OD assembly was quickly modified to enable the anchor engagement in the 13.77-in. ID liner. Within days the mills were dressed to the custom ODs required to enlarge the 12.25-in. pilot window to 13.50-in. On the first run, the whipstock was hydraulically set in the liner. Kickoff was achieved at 19,609-ft to cut a 27.5-ft window and ream a 45-ft rathole in 22 hours. The second bottom hole assembly (BHA) consisted of three mills with 12 1/2-in., 12 3/4-in., and 13-in. ODs. Milling and reaming took 6 hours. The third and final BHA to open the window to a 13 1/2-in. OD consisted of a 13 1/4-in. OD mill and two full-drift mills above. Milling and reaming with this BHA took 29 hours before coming back in with a motor assembly to drill ahead. This installation is the first sidetrack conducted with a whipstock in a 13 3/8-in. expandable. This paper will show that it is possible to safely and reliably install a casing exit system in difficult applications, such as deep expandable liners, that might previously have been considered unfeasible. This approach provides an opportunity for the industry to significantly reduce non-productive time in such scenarios.


Author(s):  
James Pawley ◽  
David Joy

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured and then plotted as a corresponding intensity in an image. The spatial resolution of such an image is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact area. A third limitation emerges from the fact that the probing beam is composed of a number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller). As in all imaging techniques, the limiting signal contrast required to recognize a morphological structure is constrained by this statistical consideration. The only way to overcome this limit is to increase either the contrast of the measured signal or the number of beam/specimen interactions detected. Unfortunately, these interactions deposit ionizing radiation that may damage the very structure under investigation. As a result, any practical consideration of the high resolution performance of the SEM must consider not only the size of the interaction volume but also the contrast available from the signal producing the image and the radiation sensitivity of the specimen.


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