Pipe Segments Research Articles

Computer Vision Technology Monitors Safety Zones and Automates Drillpipe Tally

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208764, “A Better Set of Eyes: Computer Vision Technology To Monitor Safety Zones and Automate Drillpipe Tally,” by Douglas Watson, Helmerich and Payne; Kenneth Morton, CoVAR; and Sarah Kern, SPE, Helmerich and Payne, et al. The paper has not been peer reviewed. An indispensable item for every roughneck is the tally book, used to measure and count the drillpipe entering and exiting the wellbore. Traditional manual entry is prone to error, leading to potential mistakes in the calculated drilling depth and poorly sequenced lithologies. Computer vision technology has shown promise in other industries with its ability to automate similar recognition and counting tasks. A dual-use system has been developed in which the same cameras for pipe counting can be used for red-zone-entry detection, potentially enhance the safety of the drilling process. A Dual-Use System: Monitor Safety Zones and Automate Drillpipe Tally Drilling-depth measurement commonly is performed using the drillpipe itself, and it happens in two places. It is first measured using a tape measure or pipe strap as the pipe lies on the pipe delivery system (PDS) rack before it is loaded into the stands. Then, the pipe segments are counted above the rig floor as the pipes enter and exit the borehole. This count, combined with the pipe-tally measurements, is used to determine the depth of the hole. These two work locations—ground-level PDS and rig floor—also are areas where existing procedures are in place to reduce the likelihood of serious injury. In the case of the PDS area, where pipe lengths are measured, it is dangerous to enter any time the PDS is in operation. This dangerous red zone is defined as 45 ft on each side of the PDS. Numerous industry advances over the years have made the area safer. These methods, including buffer zones (creating an understood area not to be entered or to be avoided for personal safety) and barricades (a physical block or reminder to manage entry into a high-risk buffer zone), communicate visually the potential for hazardous situations. While proper inspection, planning, and buffer-zone and barricade procedure development does communicate the safety-critical nature of the PDS environment, the potential remains for dropped-object events and tubular-handling events that can cause significant injuries or fatalities.

Efficient modelling of natural gas pipeline on electromagnetic transient simulation programs

Electromagnetic transient programs (EMTPs) are widely used for simulating electromagnetic transient in power systems. With the increasing interest in integrated energy system (IES), it would be beneficial to extend the scope of EMTP-type application to multi-physics transients in integrated electrical and gas networks. An efficient and accurate model of gas pipeline is proposed in EMTP for the simulation of pneumatic transients. The pipeline is split into a number of segments using spatial discretization. Analogies between pneumatic and electric quantities, such as flow and pressure, current, and voltage, are used to create a circuit representation of pipe segment. The pipeline is represented by a distributed-element model. In order to enhance the computational efficiency, the nodal equation for pipeline model is reformulated. The pipeline model appears as a two-port Norton equivalent with constant admittances. Case studies are performed to demonstrate the accuracy and efficiency of the proposed pipeline model. The implementation of the proposed pipeline model in the EMTP-type program power systems computer aided design (PSCAD) enables the analysis of diverse transients in integrated electrical and gas systems (IEGSs).

Investigation of the mechanical properties and corrosion behaviour of hybrid L 80 Type 1 and duplex steel joints produced by magnetically impelled arc butt welding

In the field of deep geothermal energy, the mono-tube design will be increasingly used in the future, as significant cost savings can be expected in the production of boreholes up to depths of 6000 m. The previously used bolting of the pipe lengths by means of sleeves contributes significantly to the construction costs. In addition, there is an increased risk of failure for the sleeve bolting, especially if different materials have to be used in different layers for the purpose of increasing the corrosion resistance. Magnetically Impelled Arc Butt Welding (MIAB) was used for direct welding of pipe segments with complete elimination of socket bolting. In the process, the casing material (L80 Type 1), which is a cost-effective standard material, and a corrosion-resistant duplex steel (1.4462) were hybrid welded. The results show excellent properties both in terms of mechanical properties and corrosion resistance. It is shown that the advantages of the MIAB process in joining these different materials can successfully overcome the metallurgical challenges. This new approach for the production of borehole liners can contribute significantly to cost reduction in the construction of geothermal boreholes.

Calculation of the Natural Frequencies of a Fluid-Filled Pipe System With the Coupled Codes dyvro/rohr2: Implementation of an Alternative Coupling Concept

Abstract The vibration of a pipe system can be caused by internal excitation, e.g., as a result of pump-induced pressure pulsations or external excitation like earthquake. For the investigation of these phenomena, the knowledge about the natural frequencies of the pipe system is essential. In this context, it is important to consider that the natural frequencies of the coupled system of fluid and structure commonly differ from the natural frequencies of the pure fluid system and of the structural pipe model in which the fluid is only taken into account as added mass. To obtain realistic natural frequencies of a pipe system filled with a fluid, the one-dimensional fluid code dyvro was coupled with the code rohr2stoss that deals with dynamic analysis of complex piping and steel structures. Two code coupling concepts were realized, the integral concept, which is also commonly used in coupling commercial pipe system software, and the alternative local coupling concept, with which the longitudinal deformation of the pipe segments can be captured. Both concepts consider a two-way fluid–structure interaction (FSI). For the integral concept, a verification was performed by comparison with an analytical solution for a simple case with a fluid column connected to a spring–mass system. Additionally, both coupling concepts were validated by comparison with experimental data from literature that revealed strong FSI during a water hammer event. The frequency content of the measured pressure fluctuations could be captured by both coupling concepts.

Modeling of Gas Migration in Large Elevation Difference Oil Transmission Pipelines during the Commissioning Process

Oil pipeline construction and operation in mountainous areas have increased in southwestern China, with oil consumption increasing. Such liquid pipelines laid in mountainous areas continuously undulate along the terrain, resulting in many large elevation difference pipe segments. Serious gas block problems often occur during the commissioning process of these pipelines due to the gas/air accumulation at the high point of the pipe, which causes pipeline overpressure and vibration, and even safety accidents such as bursting pipes. To solve this problem, the gas–liquid replacement model and its numerical solution are established with consideration of the initial gas accumulation formation and the gas segment compression processes in a U-shaped pipe during the initial start-up operation. Additionally, considering the interactions of the gas-phase transfer in the continuous U-shaped pipe, and the influence of the length, inclination angle, and backpressure on the air vent process, the gas migration model for a continuous U-shaped pipe is established to predict the gas movement process. Finally, the field oil pipe production data were applied to verify the model. The results demonstrate that the maximum deviation between the calculated pressure during the start-up process and real data is 0.3 MPa, and the critical point of crushing the gas in the pipe section is about 0.2 Mpa. Additionally, the results show that the mass transfer of the gas section in the multi-pipe hydraulic air vent process causes the gas accumulation section to increase in downstream of the pipe. This study’s achievements can provide theoretical guidance and technical support for the safe and stable operation of continuous undulating liquid pipelines with large drops.

A Heuristic for Strategic Valve Placement

An iterative heuristic is proposed to improve the distribution of isolation valves within an existing water distribution network to decrease the magnitude of service interruptions while using the minimum number of valves required to isolate any individual segment within the system. The method takes advantage of graph theory concepts to create a valve augmentation scheme that provides gradual upgrades using the minimum number of new isolation valves at each step. The developed algorithm seeks to provide a tradeoff between an increase in the number of isolation valves and a reduction in water shortages resulting from disconnected pipe segments. The approach is applied to an actual water distribution network with known existing valve locations. The results demonstrate the feasibility and utility of the procedure for multiple operational constraints (i.e., maximum number of valves per segment, or maximum allowable water shortage evaluated over all segments). By use of an incremental performance target set by the user, the algorithm can prove beneficial even for utilities with limited financial resources.

Accurate Estimation of Yield Strength and Ultimate Tensile Strength through Instrumented Indentation Testing and Chemical Composition Testing.

Federal rule changes governing natural gas pipelines have made non-destructive techniques, such as instrumented indentation testing (IIT), an attractive alternative to destructive tests for verifying properties of steel pipeline segments that lack traceable records. Ongoing work from Pacific Gas and Electric Company’s (PG&E) materials verification program indicates that IIT measurements may be enhanced by incorporating chemical composition data. This paper presents data from PG&E’s large-scale IIT program that demonstrates the predictive capabilities of IIT and chemical composition data, with particular emphasis given to differences between ultimate tensile strength (UTS) and yield strength (YS). For this study, over 80 segments of line pipe were evaluated through tensile testing, IIT, and compositional testing by optical emission spectroscopy (OES) and laboratory combustion. IIT measurements of UTS were, generally, in better agreement with destructive tensile data than YS and exhibited about half as much variability as YS measurements on the same sample. The root-mean squared error for IIT measurements of UTS and YS, respectively, were 27 MPa (3.9 ksi) and 43 MPa (6.2 ksi). Next, a machine learning model was trained to estimate YS and UTS by combining IIT with chemical composition data. The agreement between the model’s estimated UTS and tensile UTS values was only slightly better than the IIT-only measurements, with an RMSE of 21 MPa (3.1 ksi). However, the YS estimates showed much greater improvement with an improved RMSE of 27 MPa (3.9 ksi). The experimental, mechanical, and metallurgical factors that contributed to IIT’s ability to consistently determine destructive UTS, and the differences in its interaction with composition as compared to YS, are discussed herein.

Hybrid Laser-Arc Welding of Thick-Walled, Closed, Circumferential Pipe Welds

The application of hybrid laser-arc welding (HLAW) for joining closed circumferential welds is a challenge due to the high risk of forming a defective overlap area with a shrinkage void or solidification cracks in the material thickness. A series of HLAW experiments were performed to understand the development of a faulty overlap area when closing the circumferential weld. Welding trials on flat specimens and pipe segments were supported by numerical analyses in which the thermomechanical behavior of the welds in the overlap area was investigated. Different process control strategies were tested, including variations in defocusing levels and the overlap length. The newly developed HLAW head, including laser optics with a motor-driven collimation system, made it possible to defocus the laser beam during welding without disturbing the stability of the welding process. High-level defocusing of the laser beam of more than 40 mm relative to the specimen surface with a resulting beam diameter of > 2.9 mm, and in combination with a short overlap length of 15 mm, was promising with respect to the formation of a desired cup-shaped weld profile that is resistant to solidification cracks.

Mechanical Characteristics of Variable Cross‐Section Immersed Tunnels under Spatial Differential Settlement

This work establishes a fine model reflecting the characteristics of immersed tube structures to study the spatial mechanical characteristics of variable cross section immersed tunnels. Then, the mechanical behavior of the pipe segments under differential deformation is explored, based on which we propose a formula for estimating the shear key force and analyze the corresponding failure mechanism and failure mode. Thus, the critical points of the pipe segment design are specified. The results show that, first, the variable cross section segment bears more sectional internal force (over 47%) than the uniform cross section segment in actual cases, which should be fully considered in practical reinforcement design. Bearing deformation alternatively occurs at different shear keys, implying an apparent spatial stiffness matching problem. Second, the pipe segments show overall settlement under longitudinal bending, failing to satisfy the assumption of deformed plane sections. The force on the shear keys varies with the quadratic function of the longitudinal bending degree, and the dislocation magnitude has a positive near‐linear relationship with the bending degree. Third, when subjected to torsion, the shear keys of the weak sidewalls are sheared to resist torsion. Then, this force is laterally transferred to the top and bottom plates and jointly shared by the adjacent shear keys, explaining why shear is adjusted with structural deformation. Fourth, under the action of spatial differential deformation, the shear force is mainly undertaken by the vertical shear keys. When the structure is subjected to bending, compression and shear failure occur at the end angle of the middle wall shear key, and its root junction experiences tension and shear failure. When subjected to longitudinal torsion, the local tension and shear failure at the root of the shear key on the soft subgrade side cause a joint failure. Finally, based on the bearing characteristics, failure mechanism, and failure mode of variable cross section immersed tunnels, the idea of strengthening immersed tube structures is put forward, which can guide similar engineers.

Prediction of Pipe-Jacking Forces Using a Bayesian Updating Approach

AbstractAn accurate estimation of the jacking forces likely to be experienced during microtunnelling is a key design concern for the structural capacity of pipe segments, the location of intermedia...

A new criterion based on strain determination for dent assessment of pipelines

Dents are one of the most common defects on pipelines and compromise the structural integrity. To date, relevant studies on failure assessment of dented pipelines have been limited, and the existing standard, mainly American Society of Mechanical Engineering (ASME) B31.8, contains major problems, making assessment results not sufficiently accurate and reliable. In this work, a new method based on ductile damage failure indictor (DFDI) criterion combined with improved strain determination by a finite element (FE) model was developed for pipeline dent assessment. Dents with different depths were created by applying a spherical indenter of 100 mm in diameter on a pipe segment of 720 mm in outer diameter and 8.1 mm in pipe wall thickness. The DFDI formula considers the influence of spring-back upon removal of indenter, and the difference between the equivalent strain at dent apex and the maximum equivalent strain at the whole dent area. When the indenter displacement is smaller than 8% of pipe outer diameter, the maximum DFDI can be determined from the equivalent strain at the dent apex. When the initial displacement exceeds 8% of the pipe outer diameter, the maximum equivalent strain at the dent area, which deviates from the dent apex, should be determined by the FE model. Moreover, the limitations of ASME B31.8 in dent assessment were explained.

Investigation of Complex Characteristics of Waterjet Propulsion Device with Intake Grid

The intake grid is always installed technically to protect the impeller at the entrance of the waterjet propulsion device’s inlet duct affecting its performance. Therefore, this study discussed the complex features of the circular, rectangular, and streamlined intake grid. Consistent geometry size of the intake grid mentioned above is to be maintained to guarantee the identical flow capacity at the entrance of inlet duct. Using experimental and simulated method, the outcomes are drawn as below. Rather than the circular and rectangular intake grid, the streamlined intake grid can improve the hydraulic performance of the waterjet propulsion device. The numerical method is proved to be correct as the consistence of the hydraulic characteristic between the test and simulated results. The causes of hydraulic loss in the contraction segment and straight pipe segment are the intake grid and the inflow velocity, respectively; meanwhile, the loss in the belt pipe segment owes to the vortex, flow separation, and impact on the back. The intake grid has a positive effect on the depth of the inlet velocity profile, but a negative effect on the width of it. The intake grid installation results in thrust reduction, the progress of velocity-weighted average angle, and the regress of axial velocity uniformity. The performance of waterjet propulsion device is complex and evaluated by the hydraulic performance index (HPI), thrust performance index (TPI), and characteristic of flow pattern index (CFPI). Based on the three evaluation indexes, the streamlined scheme is raised to be the recommended scheme.

Use of optical fibers to investigate the performance of pressure pipe liners spanning across a ring fracture

Cured in place pipe liners have been used in the rehabilitation of cast iron water pipes for over twenty years. Previous research has established that the liner’s performance may be controlled by local strain concentrations that develop where the liner spans across a ring fracture in a pipe subjected to differential ground movement. This paper reports on the application of distributed strain sensing using optical fibers to quantify the longitudinal strain distribution along the inside surface of a polymer composite liner. It was confirmed that the location of maximum opening in the fracture is the critical location where the liner could experience failure. The measurements quantify how debonding (due to slip and separation between the liner and the host pipe) decreases the maximum strain in a liner and how the extent of debonding is impacted by internal pressure and the alignment of the two pipe segments across the fracture. At rotation angles of approximately 0.3°, longitudinal strains of up to 17,000 microstrain were observed in a liner subjected to internal pressure of 600 kPa. Findings from this investigation confirm that the behavior of CIPP liners installed in pressure pipes containing pre-existing ring fractures, and subsequently subjected to angular movements, should be considered in design standards.

Restrictions and obstructions detection in pipe networks using incomplete and noisy flow and pressure steady‐state measurements

Pipe networks for both water and oil distribution are prone to the formation of restrictions and, if not managed, possible obstructions. These reduce the efficiency of pipe systems and, in turn, cause negative economic impacts, temporary losses of service, and environmental risks. The present work focuses on a noninvasive methodology for the detection of restrictions in pipe networks. Restrictions are identified by minimizing, via genetic algorithms, a function that represents the discrepancy between on-field measured data and those simulated numerically. Measured data consist of a limited set of steady-state pressure heads and flow rates, which are the most commonly available information for pipe networks. The outcome of the technique is the “equivalent residual diameter” of each pipe in the network. This parameter allows the company managing the pipe network to identify the pipe segments where restrictions are most likely to be present and require further investigations. The approach is numerically validated for 15 different scenarios, considering five different sets of available measures and three different restriction conditions, in a mixed branched-looped network with complex topology for crude-oil transportation. The results show that the presence of restrictions is clearly identified and their magnitude is generally assessed with an accuracy of 5%.

Development of a physical hydraulic modelling tool for District Heating systems

Network hydraulics play a major role in the design and operation stage of District Heating (DH) systems, considering further hydraulic complexities expected in the near future. This paper presents a mathematical solution procedure that computes the network hydraulics, tailored as unique to the principal basis behind the branched type of DH networks. The procedure makes use of simple input data (i.e., pipe-node list) to obtain the mathematical description of the network layout via detection algorithms for the incidence and the loop matrices (the pseudo-code given). The matrix-based solution procedure was formulised to detect the network flow and pressure distributions either by use of the Newton-Raphson or genetic algorithms, based on the conservations of mass and energy. The problem formulation was maintained as correcting the end-user flow rates that satisfy the energy conservation throughout the closed loops of the network, which sped up the convergence to a solution. The developed model was used in a case study consisting of 220 × 2 pipe segments (supply and return) and 214 end-users, the results being obtained in 35.5 s via the Newton-Raphson algorithm. Despite the sensitivity analysis, the genetic algorithm was found to have premature convergences under various trials.

Dynamic behaviors of buried reinforced concrete pipelines with gasketed bell-and-spigot joints subjected to tunnel blasting vibration

Reinforced concrete pipelines with gasketed bell-and-spigot joints are widely spread in urban areas. The jointed concrete pipe is vulnerable subjected to blasting vibration induced by adjacent tunnel blasting excavation, which may lead to serious consequences to residents and tunnel construction. However, research on the dynamic response of jointed pipe under impact loads is vague. For analyzing the impact of blasting vibration on adjacent buried reinforced concrete pipelines with gasketed bell-and-spigot joints, full-scale blasting experiments with the pipeline buried in the silty clay layer which is a typical condition in the Wuhan area are conducted. Specifically, vibration velocity and dynamic strain variation characteristics of the pipe segments and joints subject to blasting vibration are obtained. In addition, LS-DYNA with an elaborate pipe joint model and field measuring data verification is adopted to better show the detailed response of pipe segments and joints. Comparative analysis is conducted between the continuous pipe and jointed pipe to clarify the influence of pipe joint on the whole pipeline. In the end, the countermeasures of jointed pipeline protection against blasting vibration induced by blasting excavation are presented.

Stress distribution analysis of composite repair with Carbon Nanotubes reinforced putty for damaged steel pipeline

Composite pipeline repair systems involving infill material and composite wrapper are a common method of enhancing the integrity of damaged oil and gas pipelines. Composite wrappers can be theoretically optimised by minimising the layers of wrapper whilst reinforcing the infill material; i.e., putty. Integrating nanomaterial into putty to enhance its strength is a novel approach to provide secondary layer protection of damaged pipelines. A finite element model simulating a composite repaired pipe was developed to investigate the influence of reinforced Carbon Nanotubes putty on the system's overall repair performance and behaviour. The result was verified with a previous experimental hydrostatic burst pressure test and industrial standard resulting in less than a 15% error margin. The result shows the damaged artificial pipe segment filled with two different putties, namely Grout A and Grout B, ruptured at 32.22 MPa and 32.93 MPa, respectively. The reinforced putty improved the load-bearing capacity of the repaired pipe by a marginal increment of 2.2%. It demonstrated a better load-transfer and load-sharing mechanism than the common composite repair system. The recorded burst failure of the repaired pipe was less abrupt, thus minimising the sudden rupture of the pipeline by acting as a secondary layer of protection in the event of a composite wrapper failure.

Semi-automatic identification of free span in underwater pipeline from data acquired with AUV – Case study

The purpose of this paper is to develop a routine to semi-automatically identify the free span, condition when a pipe segment is not supported by the seabed, from the images of the Synthetic Aperture Sonar and Digital Surface Model (DSM) from an Autonomous Underwater Vehicle (AUV) hydrographic survey. Currently, the free span is performed manually in sonar images, with slow and error-prone process, as it depends on human experience and attention. The methodology developed in this paper consists of extracting profiles of pipeline cross sections from the DSM, and then obtaining geometric information about each profile that will be modeled based on Artificial Neural Network (ANN) and Random Forest (RF) for free span condition classification. The ANN and RF allow evaluating and modeling the relationship between the variables extracted in the profile for the classification of free span condition. The results show that the ANN and RF provide satisfactory results for the free span condition classification with global accuracy of 86.8% and 89.9%, respectively.

Modeling and simulating nonhomogeneous non-Gaussian corrosion fields on buried pipelines and its use in predicting burst capacities of corroded pipelines

The present study proposes an iterative algorithm to simulate nonhomogeneous non-Gaussian corrosion fields on buried oil and gas pipeline's external surfaces. The algorithm incorporates the concepts of the discrete orthonormal S-transform and the iterative amplitude adjusted Fourier transform algorithm. This results in the space-wavenumber power spectral density function and marginal distribution function of the simulated corrosion field matching, respectively, their corresponding targets that could be determined from the high-resolution corrosion measurement data obtained from naturally corroded pipe segments. The simulation results demonstrate that the use of the proposed algorithm is able to capture the statistical characteristics of naturally occurring corrosion fields on pipelines. Three-dimensional elasto-plastic finite element analyses are carried out to evaluate the burst capacities of pipe segments containing simulated corrosion fields. Combined with finite element analyses, this algorithm can be employed to conduct virtual full-scale burst tests of corroded pipe specimens, which is of great value to the pipeline corrosion management practice.

Safety assessment of buried natural gas pipelines with corrosion defects under the ground settlement

Local corrosion defects of the pipeline and the ground settlement in the geotechnical engineering problem area pose a huge threat to the integrity and safety of the buried steel pipeline. The existing researches mainly focus on the design and construction of new pipelines or the safety evaluation of completed pipelines. However, the impact of pipe segments with anomalies (e.g., corrosion defects) on pipeline integrity has not been clearly and fully considered. The novelty of this study lies in the development of a nonlinear pipe-soil coupling mechanical model considering the coupling effect of the typical ground settlement and local corrosion defects of the buried pipelines. Numerical results show that the developed model is feasible to evaluate the integrity and safety of corroded pipelines under the ground settlement.