Smart Pig Research Articles

Survey on Smart Pig for Inspection Robot

Survey on Smart Pig for Inspection Robot

Design and Experimental Verification of a Novel Foam Smart PIG for Pipe Deformation Detection

Design and Experimental Verification of a Novel Foam Smart PIG for Pipe Deformation Detection

The evaluation of the bouncing model of caliper pig’s detection arm in subsea gas pipelines

Caliper pigs are widely used for measuring pipeline internal geometry and detecting anomalies, such as dents, wrinkles and flat spots. Due to its excellent transport capacity, caliper pig is more widely used in subsea gas pipelines than smart pig, such as Magnetic Flux Leakage (MFL) pig or Ultrasonic Test (UT) pig. In this article, the bouncing process of detection arm of caliper pig across convex defect is studied. And then, the influence of the collision between the detection arm and deformation defect, as well as the defect shape on the bounce, is discussed. Based on that, a bouncing theoretical model of the detection arm is developed for analyzing the bouncing phenomenon. Furthermore,the bouncing process that the detection arm moves across the convex defect with different velocities and different initial spring forces is studied by experimental method. The bouncing model calculation value is approximately equal with the experimental value, verifying the validity of the bouncing model. The bouncing model has a great significance for caliper pig evaluating the pipeline convex defect.

A review on pipeline integrity management utilizing in-line inspection data

Abstract Pipelines are widely used in transporting large quantities of oil and gas products over long distances due to their safety, efficiency and low cost. Integrity is essential for reliable pipeline operations, for preventing expensive downtime and failures resulting in leaking or spilling oil or gas content to the environment. Pipeline integrity management is a program that manages methods, tools and activities for assessing the health conditions of pipelines and scheduling inspection and maintenance activities to reduce the risks and costs. A pipeline integrity management program mainly consists of three major steps: defect detection and identification, defect growth prediction, and risk-based management. In-line inspections (ILI) are performed periodically using smart pigging tools to detect pipeline defects such as corrosion and cracks. Significant advances are needed to accurately evaluate defects based on ILI data, predict defect growth and optimize integrity activities to prevent pipeline failures, and pipeline integrity management has drawn extensive and growing research interests. This paper provides a comprehensive review on pipeline integrity management based on ILI data. Signal processing methods for defect evaluation for different types of ILI tools are presented. Physics-based models and data-driven methods for predicting defect growth for pipelines with different categories of defects are discussed. And models and methods for risk-based integrity management are reviewed in this paper. Current research challenges and possible future research trends in pipeline integrity management are also discussed.

Ultrasonic diagnostics of main pipelines

Abstract The main pipelines, like many engineering structures, are subject to high operational safety standards. The safety of their operation is supervised by various institutions from the operator, including supervisors such as the Office of Technical Inspection. Safe operation requires knowledge of their technical condition and trends. One of the important sources of information on the condition of pipelines is their periodic inspection carried out with so-called smart pigs. As a result of the inspection, the operator expects the following questions to be answered: what is the condition of the pipeline examined; where and what metal losses are occurring in its construction; what are the hazards causing these damages for the safety of the pipeline operation; what is the rate of increase in the size of metal losses in the pipeline wall. This article presents technical solutions and methodology to answer the above questions.

Strength Assessment of a Corroded Pipeline through the Burst Test: Case Study

AbstractFailure due to corrosion has become one of the major problems in maintaining pipeline integrity. Smart pigs have been used for decades to assess the in situ condition of steel pipe serving the oil and gas industries. The assessment techniques used are generally described in standards prepared by American Petroleum Institute (API) and American Society for Testing and Materials (ASTM). These standards are viewed by some in the industry as being conservative, resulting in premature repair or replacement of pipelines. Therefore, pipeline operators need better, more reliable condition assessment tools, not only to assure safe operations, but also to optimize maintenance costs. That is to repair or replace only the pipe sections that need the remediation. Recently, an alternative condition assessment method was developed using finite element (FE) analyses that were validated through actual pipe burst tests results. In this paper, the burst test procedure and results of testing a 250-mm (10-in.) nominal ...

Automatic welding detection by an intelligent tool pipe inspection

This work provide a model based on machine learning techniques in welds recognition, based on signals obtained through in-line inspection tool called “smart pig” in Oil and Gas pipelines. The model uses a signal noise reduction phase by means of pre-processing algorithms and attribute-selection techniques. The noise reduction techniques were selected after a literature review and testing with survey data. Subsequently, the model was trained using recognition and classification algorithms, specifically artificial neural networks and support vector machines. Finally, the trained model was validated with different data sets and the performance was measured with cross validation and ROC analysis. The results show that is possible to identify welding automatically with an efficiency between 90 and 98 percent.

A novel smart caliper foam pig for low-cost pipeline inspection—Part A: Design and laboratory characterization

Abstract Pipeline pigging for in-line inspection is a fundamental practice in the oil and gas industry. Yet, the so-called “smart pigs” used for this purpose are expensive and delicate and the risk related to their possible blocking inside the pipeline is non-negligible, hence their deployment is rather infrequent (generally, just once in several years). In this paper, we present a new, low-cost and low-risk foam pig with inspection capabilities similar to those of a multi-channel caliper pig (i.e. able to detect, locate and size inner diameter changes and deformations) together with additional features that allow to detect internal roughness changes (e.g. due to corrosion) and perform some pH/salinity determinations, also useful for corrosion assessment purposes. One implementation of the new tool makes use of a foam pig “carrier”, providing the required push with a good capability to surpass restrictions, equipped with specialized sensors and modules for data acquisition and storage. Another implementation, called “skeleton caliper pig” and suitable to prevent the massive displacement of condensates from gas lines, deploys the light plastic system without any foam pig carrier, pushed by the gas velocity alone. In the paper we will discuss the design, construction and field testing of this new low-risk inspection pig.

Active incremental Support Vector Machine for oil and gas pipeline defects prediction system using long range ultrasonic transducers

This work proposes a long range ultrasonic transducers technique in conjunction with an active incremental Support Vector Machine (SVM) classification approach that is used for real-time pipeline defects prediction and condition monitoring. Oil and gas pipeline defects are detected using various techniques. One of the most prevalent techniques is the use of “smart pigs” to travel along the pipeline and detect defects using various types of sensors such as magnetic sensors and eddy-current sensors. A critical short coming of “smart pigs” is the inability to monitor continuously and predict the onset of defects. The emergence of permanently installed long range ultrasonics transducers systems enable continuous monitoring to be achieved. The needs for and the challenges of the proposed technique are presented. The experimental results show that the proposed technique achieves comparable classification accuracy as when batch training is used, while the computational time is decreased, using 56 feature data points acquired from a lab-scale pipeline defect generating experimental rig.

Hydrocarbon–metal reactions during metal arc welding under oil (MAW-UO)

Metal arc welding under oil is a new, revolutionary process for the repairs of pipelines which should minimise the need of hot tapping repairs and the construction of bypass lines. The process uses an automated metal arc welding set-up with a continuous wire feed. This process was developed for the in situ internal repairs of in service cross-country pipelines, tanks and vessels by using a smart pig with a modified mechanical design that allows for joint preparation and welding. The unique characteristics found in the under oil arc are discussed in detail. The large range of temperatures that exists between the arc at the order of 10 000°C (18 000°F) and the surrounding oil (ambient) allows for complex reactions between the oil hydrocarbon chains and the steel weld metal. These reactions may considerably impact the weld microstructure. Details of the dissociation of hydrocarbon chains and ionisation of the resulting species must be known to better control the process. In addition, vaporisation of the oil will form oil vapour bubble to surround the welding arc. The oil vapour bubble will also be high in decomposed products that can significantly affect the weld metal composition. Gas chromatography–mass spectrometry was used to investigate the behaviour of a welding arc under oil and the carbon pick-up. Analyses were conducted on oil samples with different welding exposure times to validate the arc behaviour mechanistic model and the gas chromatography–mass spectrometry analysis results.

Flaw Location of Pipeline based on the Accelerometer

The pipeline is the most economic and effective means to transport large quantities of oil and natural gas over long distances. However, in the long term, pipeline flaws may appear because of erosion, abrasion, unexpected damage and so on, which would weaken the pipeline safety performance and even result in leakage and pipe explosion accidents. For timely discovery of flaws and establishing optimal strategy of maintaining the pipeline, the in-served pipeline will be periodically online evaluated by using the smart PIG (pipeline inspection device) to detect flaws and locate them in the body of the pipeline. A method for flaw location of the pipeline is presented in this article, where a high resolution servo accelerometer CX-3 is used to measure the axial acceleration of the smart PIG in a pipeline to acquire the precise distance walked by the smart PIG by integral operation of the acceleration value to time variable and error correction. Basing on the linear relation between the distance and time label a flaw location precision about 0.2% can be reached by indoor experimental measurement. This experimental result shows that the location precision based on the accelerometer is higher than the Odometer wheels now in use and the technology will satisfy the pipeline inspection need by further research and development.

Characterization and Evaluation of the Integrity of the Onshore Pipelines

ABSTRACTThe pipelines are the main transport and distribution system of production in the oil industry, which are subject to environmental and operational conditions which are not favorable for the operation of the pipelines and sometimes represent the risk of accidents and high economic losses. The evolution of risk begins with a systematic search of possible threats to the integrity of the pipeline. The identification of potential threats should not be limited to known risk categories reviewed, but must complete the steps to find new and unique expressions of risk and the study of particular cases. Thus, the importance of a comprehensive risk assessment of the transmission pipeline is crucial. In this paper an integrity assessment for corrosion damages in pipelines was developed through a methodology based on risk analysis to estimate the propagation rate on the time, the size, location and number of damages. To perform this study a data obtained from smart pig runs and an artificial neural network (ANN) model with retro propagation was used. From the data obtained from launching smart pigs on the pipeline it was carried out the training of the neural network, later on it was applied the network previously trained to get the predictions of damages on the pipeline, considering that pipeline did not have any maintenance.

How to See the Unseen City

This paper presents different methods and equipments used on how to inspect underground infrastructures, networks, sewers, and pipes in some cities around the world. In New York, underground pipes are inspected using an electronic listening equipment as its first line of defense. Maintenance workers dangle a microphone down a manhole and attach it to a water main to assess whether flow has been disturbed by a leak. More detailed checks are conducted from within a pipe, using what is essentially a video camera on wheels. In pipeline lingo, such tools are quirkily known as smart pigs. In addition to capturing a digital video, a pig can perform radar and sonar scans above and below a water line, searching for indentations and holes in the walls as it rolls down in a pipe. It records its locations with odometer wheels and may be equipped with magnetic sensors to check for aberrations in metal pipes. On the other hand, Japan is the exception on the geospatial-information services front, with a national mapping repository known as ROADIC. This underground mapping system consists of utility grids layered over a road map that utilities and builders consult before breaking ground.

Condition Assessment of Water Distribution Pipes

With average pipe replacement rates in the United States at about once in 200years, effective assessment of pipe condition is required to plan renewal programs for distribution systems. The paper is based on a project for the American Water Works Association Research Foundation and presents findings and a management framework about utility practices in condition assessment and it validates the framework through comparisons with practices in leading utilities. The project findings indicated that utilities can utilize available information much better than they do. However, they are impeded by lack of a standard procedure for recording data on leaks, breaks, and condition indicators. Ideally, the large amount of information involved would be consolidated into a composite condition index, but this is not feasible. Advanced applications are required for the future. These might include real-time assessment, smart pigs to collect data, small chip sets, and automated pipe data registration. Research needs are indicated in nondestructive testing, leak detection and loss measurement, causes for pipe, joint, lining, and coating deterioration, and in situ methods to test condition. While condition assessment is a promising concept, it is not applied consistently. In the past, condition information was used by operations and engineering departments. The same decisions still require condition information, but organizations are more integrated, have newer methods available, and face higher standards and expectations than in the past. When utilities manage their distribution capital programs better, it can lead to organizational improvement across the board because different departments can work together to improve the entire system. By use of the proposed framework, combined with effective information systems, operations improvements, and capital improvement programs, utilities can optimize returns on their investments in distribution systems. Utilities will continue to face obstacles such as lack of records, inability to inspect pipes while in service, and not being supported for funding by boards or councils. In the end, the solutions may already be within the grasp of utilities, through better management of existing information.

Assuring the integrity of natural gas transmission pipelines. Topical Report, November 1992 : Posakony, G.J.; Hill, V.L. J-TECH Consulting, Richland, Washington (United States), PB93184364/GAR, 74pp. (Nov. 1992)

The existing 370,000 miles of U.S. natural gas gathering and transmission pipelines were constructed principally during the past four decades. Since more than 30 percent of the energy produced domestically is natural gas, assuring the long-term integrity of the transmission system is a vital element in meeting the energy needs of the nation. The preventive maintenance programs established by the gas industry are key to extending the service life of this national asset. The report, one of four covering pipeline maintenance and inspection, describes the types of third-party and service-induced conditions that have caused leaks and rare failures in natural gas transmission pipelines. Also overviewed are the preventive maintenance practices currently available to survey, monitor, and test the pipe and to locate conditions which might be adverse to the safety, serviceability and integrity of the system. These include right-of-way surveys and patrols, monitoring of corrosion protection systems, in-line inspection with smart pigs, bellhole excavations and hydrostatic retesting.

Integrity Assurance of Natural Gas Transmission Pipelines

Natural gas transmission pipelines have proven to be a safe and efficient means for transporting the trillions of cubic feet of natural gas used annually in the United States. Since the peak of construction of these pipelines occurred between 1950 and the mid-1960s, their average age is now over thirty years. However, replacement of these pipelines because of age would be prohibitively expensive and unnecessary. Preventive maintenance and rehabilitation programs put into practice by the pipeline industry provides the key to ensuring the continued integrity of the transmission pipeline system. This article reviews the preventive maintenance practices commonly used by the gas industry. These practices include right-of-way patrols, corrosion control procedures, in-line inspection with intelligent or smart pigs that inspect the pipe while traveling through the inside of the pipe, direct access inspection of the pipe from bellhole excavations, and hydrostatic retesting of pipelines. When pipelines are properly maintained, these practices can ensure the integrity and long-term serviceability of transmission pipelines well into the 21st Century.

An Evaluation Of Corrosion Monitoring Techniques For Measuring Corrosion Inhibitor Performance In Sour Gas Gathering Systems

Abstract Amoco Canada Petroleum Ltd. operates approximately 50 sour gas wells in the Fox Creek area of Alberta. Historically, anodic polarization probes and corrosion inhibitor residual measurements have been utilized to monitor corrosion inhibitor performance and to verify system inhibition. In this study, a wellhead test loop was installed to compare various corrosion monitoring techniques and to determine the effectiveness and cost performance of several new corrosion inhibitors. Anodic polarization was useful for measuring relative corrosion rates and relative inhibitor performance. In view of the differences observed between anodic polarization measurements and corrosion coupons, the former technique should be used in conjunction with corrosion coupons, particularly when evaluating new corrosion inhibitors. In the test protocol, electric resistance probes were not useful for short-term inhibitor evaluation, although they warrant further investigation as a long-term monitoring technique in systems where the inhibition criteria have been previously established. The hydrogen probe was not sensitive or responsive to changes in corrosion inhibitors, or inhibitor injection rates. Although the exposure time of the corrosion coupons was typically six to eight days, the polished rod coupons provided valuable metallurgical response to the various inhibitors tested. Finally, corrosion inhibitor residuals were useful for verification of inhibitor injection rates and correlated well with the optimum concentrations determined by laboratory studies. Introduction Corrosion History Production from the Kaybob South Beaverhill Lake gas field began in 1968, with initial projections for low water production. However, severe water coning occurred immediately and water production rates were much higher than originally anticipated. As the water rates increased, so did the chloride content of the produced water. The combination of these two factors resulted in several internal corrosion problems. The resulting failures were caused by isolated pitting attack in the bottom quadrant of the pipeline in low velocity areas, and in low elevation areas where produced fluids accumulated. The design of the gas gathering system precluded any form of pigging or detailed line inspection using smart pigs. Consequently, the development of an effective water soluble or highly water dispersible corrosion inhibitor was required to control internal corrosion in the gas gathering system. Initially, control of the chemical injection program was extremely difficult due to two factors a continually increasing water production rate and infrequent well testing, as well as limited access points for obtaining water samples for inhibitor residual testing. Line failures continued to be a problem until an extensive testing program was initiated, which provided the information required to predict and set maximum flow rates to stabilize water production. A water soluble/dispersible inhibitor was developed during the same period and the combination of these two factors resulted in the successful control of internal corrosion problems in the Kaybob South gas gathering system. Throughout the life of the field, the following factors have significantly contributed to the development of a successful corrosion inhibition program.Extensive well testing allowed ongoing monitoring and projection of water production rates.The development of a corrosion inhibitor which exhibited significant water solubility dispensability.

Running Risks with Language: Contemporary Prose and Poetry for Children in West Germany

Running Risks with Language:Contemporary Prose and Poetry for Children in West Germany Jack Zipes (bio) Dimension, vol. , no. , edited by Karlhans Frank. University of Texas Press, 1979. During the last fifteen years in West Germany there has been a remarkable development of experimental children's literature. Whereas German writers had shied away from dealing with thorny problems of childhood experience in the immediate postwar period, they rose to the forefront of a general European reform movement in the late 1960s that sought to make children's literature socially more realistic and emancipatory at the same time (see my essay in Children's Literature, 5 [1976]). It is difficult for an English-reading public to obtain translated texts of this new German children's literature, so that the special issue of Dimension, edited by Karlhans Frank and containing stories and poems, fills a need by helping us to gain a sense of the experimentation in West Germany. Frank's anthology is the first to appear in English with the German originals on the opposite pages. Frank is a gifted writer of children's books in his own right. Since 1968 he has produced numerous volumes of poetry and prose for children, written television scripts for children's shows, and developed four "Sesame Street" paperbacks for educators. His most recent children's book is Was macht der Clown im ganzen Jahr? (What Does the Clown Do All Year Long?), published in 1978. Here, as the guest editor of this thematic issue of Dimension, he has gathered together approximately twenty-two texts in prose and poetry—along with several unique illustrations—for children between the ages of six and fourteen. He does not presume or want to pretend that this is a "representative" volume of the best texts for children by West German authors; rather, he has made a careful and sensitive selection of provocative stories and poems that challenge young readers' minds. All of them are admirably translated by [End Page 191] different persons under the guidance of A. Leslie Willson, the general editor. To begin, the thematic issue of Dimension is introduced by Ruth Lorbe's insightful essay on West German poetry for children. Lorbe presents several interesting examples of recent experimentation with motifs, rhymes, sounds, and structure to indicate how poems can make the young reader "aware of all the possibilities that lie in the language, and . . . invite him to have confidence in the language, to run risks with language." This sets the tone for the rest of the volume, for Frank has collected stories and poems that reflect how the authors themselves run risks with language and how young readers can follow these risks. In the course of reading all the texts, one learns not only about artistic endeavors on behalf of children in West Germany but also about social conditions in the Federal Republic. Since it would be difficult to summarize all the fine contributions to this volume, I want to cite some of the more interesting concerns of the authors and the expressive forms that they have developed. Three stories—Gina Ruck-Pauquet's "Red Man and Red Girl," Iring Fetscher's "The Frog Prince—How It Continued," and Gunter Herburger's "The Cement Dwarf"—exemplify the ways in which numerous West German authors have reutilized fairy-tale motifs to question the irrational and unjust conditions in modern society. Frank's own contribution, "The Really Sad Story of the Smart Pig," borders on the fairy-tale genre, but it is more a short fantastic and symbolic speculation about the nature of oppressed creatures. On the realistic side, there are penetrating sketches of family and social life in the Federal Republic—all drawn with a sympathetic eye for the difficult situation of youngsters. Hans Christian Kirsch's "Quarreling" is a sensitive portrayal of a brother and sister who develop stronger bonds of love while observing how the relationship between their parents becomes more bitter. Wolfgang Fienhold's story, "Fatso," deals poignantly with unwarranted prejudice against odd-looking children. Carola Benninghoven's "Ilona Doesn't Go Home at Noon" allows readers to gain insight into the sufferings of a child who is neglected by her [End Page 192...