Distance Pipeline Research Articles

Pipeline deformation monitoring using distributed fiber optical sensor

Deformation of long distance pipeline takes place more easily under the various adverse factors such as freezing-thaw and earthquake, and oil and gas often leak from the broken pipeline once the deformation has exceeded a previously established threshold. In order to solve the hot issue on the pipeline deformation monitoring, this research was launched on the basis of the combination of distributed fiber optical sensor and conjugate beam method. One finite element model of a pipeline with the length of 50 m and one PVC (Polyvinyl Chloride) pipeline with the length of 4 m were constructed to validate the deformation method, respectively. The finite element pipeline model was loaded vertical displacement at different positions simultaneously, and the PVC pipeline was gradually applied different level of loads at the midspan. In the two tests, the continuous or distributed strain data and the discrete strain data were used to calculate the deformation of the pipeline based on the conjugate beam method. In order to validate the deformation monitoring method, a comparison between the displacement curve calculated by the distributed strain data and that calculated by the discrete strain data was conducted. The results of the two tests indicate that the deformation of the pipeline can be well monitored and the method can be applied to the field applications.

Surge Tank Analysis for Water Hammer Remedy for Long Distance Pipeline

Various protection methods can be used for protecting the pipeline system from the impact of water hammer. Which includes the use of special materials for supporting the pipeline and the installation of special devices such as surge tanks, relief valves, and air chambers. In this study, to protect the pipeline system and reduce the effect of water hammer, surge tank has been used. Governing equations of transient flow with and without surge tank is numerically simulated using MATLAB software. Sensitivity analysis was investigated using several variables such as pipe diameter, wave’s velocity and friction factor. Method of characteristics (MOC) was implemented in this study. It was found that the diameter and friction factor of pipe have a significant impact on the results of transient flow and surge tank compared to the effect of wave’s velocity. It has been reached that the capacities of surge tanks at diameter (1m), are (1475m3) at first, second and fourth stages, (1360m3) at third and fifth stages and (570m3) at sixth stage. And at diameter (1.2m), the capacities are (1700m3), (1530m3) and (1475m3) at first, second and third stages respectively. But at diameter (1.4m), the capacities are (1590m3) at first and second stages. For all values of wave’s velocity, the capacities of surge tanks are (1760m3), (1530m3) and (1420m3) at first, second and third stages respectively. But the capacities of surge tanks at friction factor (0.007) are (1810m3), (1585m3) and (1245m3) at first, second and third stages respectively. However, for the capacity of surge tanks at the friction factor (0.008), it was mentioned when the surge tanks capacity of the diameter (1.2m) was mentioned. And when the friction factor is (0.009), the capacities are (1460m3) at first stage, (1415m3) at second and third stages and (570m3) at fourth stage

Reliability research on automatic ultrasonic testing (AUT) technology of land long distance pipeline with automatic welding joint

The complete automatic ultrasonic testing (AUT) reliability theory and evaluation system were established for automatic welding joint of long distance pipeline. The reliability of AUT system was verified by several indexes, including Probability of Detection (POD), Probability of Sizing (POS), Probability of False Alarm (PFA), Probability of Rejection (POR) and Receiver Operating Characteristic (ROC). In order to evaluate AUT process and analysis reliability of AUT system, the sample size was optimized to 46 and the quantitative data of defects in AUT, RT and macroscopic metallographic section were analyzed statistically, which could directly provide reliable quantitative bases for the automatic welding quality acceptance of AUT Technology. The results show that POD and reliability of AUT are not less than RT, which can provide support for AUT application to automatic welding of the domestic long distance pipeline.

Effect of dispersing time on the prediction equation of drag reduction rate and its application in the short distance oil pipeline

ABSTRACTThe effect of the drag reducer, which is a kind of effective chemical additive for the pipelines, is closely related to its dissolution dispersity in the oil product. In this paper, the effects of oil viscosity, temperature and concentration of the drag reducer on the dispersion rules of drag reducer in crude oil and refined oil are analyzed and the modified Equation for prediction of the drag reduction rate was proposed. For short distance pipeline, a method of drag reducer dispersed beforehand was developed and proved in diesel pipeline, which effectively promotes the application effect of drag reducer in short distance pipeline.

Optimization of multi-plants cooling water system

Conventionally, cooling water system is optimized within a single plant. In reality, a set of cooling towers supply water for multiple plants. This paper presents an optimization model for multi-plants cooling water system. Instead of using a set of uniform pumps to transport cooling water, this work proposed a novel multi-loops pump network and an updated main-auxiliary pump network to reduce pumping energy. Distance factors and pipeline layouts are considered owing to the long distance between plants and pump station. Connecting patterns of different pump networks are investigated and corresponding piping costs are treated as optimized variables. Cooler and pump networks, cooling tower and pipeline layouts are optimized simultaneously. The model is formulated as a mixed-integer nonlinear programming (MINLP) problem. The objective is to obtain the cooling water system with minimized total annual cost. Two case studies are used to illustrate the effectiveness of the proposed structure.

The relevance of water recirculation in large scale mineral processing plants with a remote water supply

Abstract Water and energy are essential requirements for mineral processing plants, and they can be either scarce or expensive. In the present paper, the implications of a remote water source location (typically the seashore) are analyzed in terms of a definition for the combined water and energy operational cost required to transport ore concentrate using long distance pipelines. A typical process route is defined to expose the relevance of key process variables, including source remoteness and water reclamation both from tailing storage facilities and thickeners. Both mass and energy balances have been made to give an estimation of specific energy consumptions for a typical large scale Chilean mineral processing operations, considering a number of realistic hydraulic design criteria to make a comparative analysis of different plant processing capacities. In the present cost function definition, an account has been made on whether the water is either makeup or has been recirculated on the plant, and a distinction has been made on whether tailings are conventional or thickened, which allowed to analyze the relevance of in-plant water recovery compared to water recovery from the tailing disposal site. This has allowed to express the cost of water in terms of the various energy cost terms, thus showing in this case that the cost of water is ultimately the cost of energy, and therefore all cost components become proportional to the unit cost of energy. A piecewise constant pipeline diameter analysis scheme has been defined to allow studying the implications of water recovery on widely different plant sizes. Results show that for fixed water recovery rates, increasing plant throughput tends to cause a decrease on the specific energy for water transport. On the other hand, for fixed pipeline diameters, increasing the throughput causes an increase on the specific energy consumption, but such increase rate becomes milder at higher throughput rates. This suggests the advantage of the existence of common makeup water supply systems for mining districts with more than one mineral processing plant. On the other hand, for constant pipeline diameters, increasing the water recovery from the tailing disposal site or from thickeners generates a decrease of water specific energy consumption, where in the case of the water recovery from the tailing disposal site such decrease rate becomes stronger with the amount of water recovered. Results also shows that, except for very high solid concentrations, water makeup costs dominate over recirculation ones, supporting that producing thickened tailings is a more efficient option than conventional ones in the sense of specific energy consumption, in spite of the additional energy costs due to slurry transport that this option implies.

Operational Energy Saving Potential of Thermal Effluent Source Heat Pump System for Greenhouse Heating in Jeju

Massive thermal effluent energy from power plant is mostly released to the sea, and only a little is used for fishing culture and agriculture in South Korea. The thermal effluent from the power plant can be an efficient heat source of the heat pump system to provide heating energy for the greenhouse, but energy loss and pump power by long distance pipeline installation from a power plant to the greenhouse should be considered. In this paper, an operational energy saving potential of a thermal effluent source heat pump system for the greenhouse heating was investigated. For the estimation of thermal load, three cases of greenhouse were categorized, and the thermal performance and operating energy consumption during the heating season were compared with those of a conventional ground source heat pump (GSHP) system. The model for heat pump system was newly derived to estimate the energy performance of the proposed system, and then detailed simulations for each system under three cases of greenhouse were conducted. The results showed that the operational energy of the proposed system can be saved by 17–20% than that of the conventional GSHP system.

Water hammer suppression for long distance water supply systems by combining the air vessel and valve

In long distance water supply projects, the air vessel is an effective and reliable protection measure to control water hammer. Although it can effectively eliminate water hammer during the process of hydraulic transient, the volume of the traditional air vessel is large due to the long distance pipeline, resulting in high investment. In this paper, based on the analysis of the transient in long distance water supply pipelines, a protection method, combining the air vessel with the downstream valve, is proposed to reduce the volume of the air vessel, keeping the system pressure within the limit. Furthermore, an innovative arrangement of the air vessel is presented to overcome the risk of the combined protection method. Besides the upstream air vessel, a downstream air vessel is additionally installed to mitigate positive water hammer due to rapid closure of the downstream valve. To verify the effect of the new method, the numerical model was established according to the parameters of a practical water supply project, and hydraulic transient due to pump trip was simulated. Compared with the traditional method, the combined protection method provides effective water hammer protection and greatly reduces the volume of the air vessel.

Residual stress measurements in steel pipes using DSPI and the hole-drilling technique

The oil and gas industry employs long distance pipelines to simplify the transport logistic and to reduce the final costs of petroleum derivatives. For the construction of pipelines, nowadays it is usual the application of pipes which are manufactured by cold forming operations. The high level of the non-uniform plastic deformation of the steel during the pipe manufacturing process produces residual stresses. These stresses are internally self-equilibrated, but locally can affect the structural integrity of the pipeline. Therefore, an accurate measurement of residual stresses is important to guarantee a safe and healthy pipeline network. This paper shows the application of a portable optical device combining digital speckle pattern interferometry and the hole drilling technique to measure residual stress fields in pipe samples manufactured by the UOE-SAW and ERW processes. A set of 72 measurements were performed in order to scan the residual stress distribution along the external surface of each pipe. On the other hand, a smaller set of measurements were performed in the internal surface of an ERW pipe sample. Considering all cases, the mapping has revealed the presence of stress profiles which were compressive in the first half of the hole and tensile in the second one. Additionally, the external measurements demonstrated a good repeatability between them, indicating a similar stress behavior along the circumferential and longitudinal directions of the pipe.

A comparison between ACO and Dijkstra algorithms for optimal ore concentrate pipeline routing

One of the important aspects pertaining the mining industry is the use of territory. This is especially important when part of the operations are meant to cross regions outside the boundaries of mines or processing plants. In Chile and other countries there are many long distance pipelines (carrying water, ore concentrate or tailings), connecting locations dozens of kilometers apart. In this paper, the focus is placed on a methodological comparison between two different implementations of the lowest cost route for this kind of system. One is Ant Colony Optimization (ACO), a metaheuristic approach belonging to the particle swarm family of algorithms, and the other one is the widely used Dijkstra method. Although both methods converge to solutions in reasonable time, ACO can yield slightly suboptimal paths; however, it offers the potential to find good solutions to some problems that might be prohibitive using the Dijkstra approach in cases where the cost function must be dyamically calculated. The two optimization approaches are compared in terms of their computational cost and accuracy in a routing problem including costs for the length and local slopes of the route. In particular, penalizing routes with either steep slopes in the direction of the trajectory or high cross-slopes yields to optimal routes that depart from traditional shortest path solutions. The accuracy of using ACO in this kind of setting, compared to Dijkstra, are discussed.

Establishment and application of service mapping model for proactive remanufacturing impeller

Since the complex impeller structure and the difficult remanufacturing process may easily cause advance remanufacturing or excessive use, an optimized design method of impeller and service mapping model was presented for its proactive remanufacturing with setting up to explore the best remanufacturing time point in this work. Considering a certain model of long distance pipeline compressor impeller with the Basquin equation and the design method of impeller, the mathematical relationship between the changes of structure and life of the impeller was established. And the service mapping model between the structure and life was set up and simulated by ANSYS software. Thus, the service mapping model was applied to feedback the original design for proactive remanufacturing. In this work, the best proactive remanufacturing time point of impeller was analyzed with the service mapping model, and the structural parameter values could be optimized at this time point. Meanwhile, in the results of this simulation, it proves that the impeller under this optimization performance could satisfy the impeller operating demands. Therefore, comparing with the traditional optimization design method, the remanufacturing optimized design based on the service mapping model is feasible in proactive remanufacturing for sustainable development.

Chaos characteristics and least squares support vector machines based online pipeline small leakages detection

Small leakages are severe threats to the long distance pipeline transportation. An online small leakage detection method based on chaos characteristics and Least Squares Support Vector Machines (LS-SVMs) is proposed in this paper. For the first time, the relationship between the chaos characteristics of pipeline inner pressures and the small leakages is investigated and applied in the pipeline detection method. Firstly, chaos in the pipeline inner pressure is found. Relevant chaos characteristics are estimated by the nonlinear time series analysis package (TISEAN). Then LS-SVM with a hybrid kernel is built and named as hybrid kernel LS-SVM (HKLS-SVM). It is applied to analyze the chaos characteristics and distinguish the negative pressure waves (NPWs) caused by small leaks. A new leak location method is also expounded. Finally, data of the chaotic Logistic-Map system is used in the simulation. A comparison between HKLS-SVM and other methods, in terms of the identification accuracy and computing efficiency, is made. The simulation result shows that HKLS-SVM gets the best performance and is effective in error analysis of chaotic systems. When real pipeline data is used in the test, the ultimate identification accuracy of HKLS-SVM reaches 97.38% and the position accuracy is 99.28%, indicating that the method proposed in this paper has good performance in detecting and locating small pipeline leaks.

The Technique of Segmental Pigging Process for Long Distance Pipeline of Oil and Gas in China

Worldwide, the pipeline mileage has increased dramatically since 1948 when the industry began to keep mileage statistics for pipeline construction, especially in China. Before operating long distance oil and gas pipelines, the pressure testing for tightness and strength is of great importance for ensuring operating safety. Water is used as service fluid for the pressure testing due to its safety, and long distance pipeline is divided into a number of small sections according to complex terrain conditions. Segmental water pressure testing is now very frequently used in the oil and gas industry, ensuring safety and efficient construction of pipelines. However, some new problems may arise, in practice, for the pigging process, following water pressure testing. Based on the review of previous papers about pipes accidents, the causes can be classified into hydraulic and nonhydraulic aspects. With the method of characteristic (MOC) and basic theory of gas–liquid two-phase unsteady flow, a mathematical model is developed to simulate the hydraulic transients during the pigging process. The model has been applied to some segmental pipes in China to predict varying pressures under complex terrain conditions. Pressure pulses predicted at the end of pigging in the numerical results have also been found to occur in field trials. The analysis shows that pressure pulses may cause overpressure accidents due to vapor cavity collapse. The techniques in this paper can give reasonable instructions in long distance pipeline constructing, promoting the development of Chinese oil and gas industry.

A numerical study on water wetting associated with the internal corrosion of oil pipelines

Long distance pipelines are considered as the vein of the oil and gas industry on land and offshore. A well often produces water along with crude oil. The presence of water as well as dissolved gases such as CO2 and H2S introduces a serious menace of internal corrosion. It is well known that the distribution of water and oil inside the pipeline has a great influence on the corrosion rate. As a matter of fact, internal corrosion occurs when a free layer of water comes in contact with the pipe. Hence, predicting the distribution of water inside the pipe and identifying the continuous phase that directly wet the wall is of foremost importance when dealing with internal corrosion of oil pipelines. The accurate prediction of the distribution of water significantly increases the accuracy of corrosion prediction as well as the confidence regarding the integrity of the pipelines. In spite of all the great efforts toward studying different influential factors associated with the internal corrosion of steel pipelines, a large gap of knowledge is observed in predicting the water wetting. The objective of the present study is to employ a tuned two-fluid model by taking advantage of computational fluid dynamics, that is capable of predicting the distribution of water and the type of wetting (water wetting/oil wetting) at the bottom of the pipe. Furthermore, the effect of different parameters such as pipe diameter, oil density, oil viscosity and interfacial tension on the transition from water wetting to oil wetting is studied.

Algorithm for the selection of multiple VSPs

In recent years, the variable speed pumps (VSP) are widely used in all walks of life. With respect to the oil & gas industry, they are one of the most important equipment in the long distance pipelines. To prevent the phenomenon of throttling, which would cause unnecessary energy waste, the variable drives are utilised connected to the axes of the pumps.

EARNPIPE: A Testbed for Smart Water Pipeline Monitoring Using Wireless Sensor Network

Large quantities of water are wasted daily due to leakages in pipelines. In order to decrease this waste and preserve water, advanced systems could be used. In this context, a Wireless Sensor Network (WSN) is increasingly required to optimize the reliability of the inspection and improve the accuracy of the water pipeline monitoring. A WSN solution is proposed in this paper with a view to detecting and locating leaks for long distance pipelines. It combines powerful leak detection and localization algorithms and an efficient wireless sensor node System on Chip (SoC) architecture. In fact, a novel hybrid Water Pipeline Monitoring (WPM) method has been proposed using Leak detection Predictive Kalman Filter (LPKF) and Modified Time Difference of Arrival (TDOA) method based on pressure measurements. The data collected from sensors are filtered, analyzed and compressed with the same Kalman Filter (KF) based algorithm instead of using various algorithms that deeply damage the battery of the node. The local low power pre-processing is efficient to save the power of the sensor nodes. Moreover, a laboratory testbed has been constructed using plumbing components and validated by an ARM-based prototyping platform with pressure sensors.

A Calculation Model for Gas Transmission Efficiency of Long Distance Pipelines

Due to the formation of corrosion products, natural gas liquids and gas hydrates in long distance pipelines, timely and effective pigging operations are necessary to improve the gas transmission efficiency, reduce pressure loss, as well as guarantee the safe operation of gas wells, pipelines and networks. Gas transmission efficiency is a parameter to reflect the working condition and cleanliness of pipelines, which is calculated by the division of actual gas transmission volume and theoretical gas transmission volume. In consideration of the characteristics of long distance gas pipelines, a calculation model of gas transmission efficiency is presented in this paper. A threshold value of 90% is used to measure the running state of pipelines, so as to determine whether a pigging operation should be conducted. The influence factors are analyzed. Suggestions on the operation strategy of long distance gas pipelines are stated.

Stress analysis of parallel oil and gas steel pipelines in inclined tunnels.

Geological conditions along long distance pipelines are complex. In consideration of differences in elevation and terrain obstacles, long distance pipelines are commonly laid through tunnels. Oil and gas pipelines are often laid side by side to reduce construction costs and minimize geological impact. The layout and construction of parallel oil and gas pipelines are more complex than those of single pipelines. In order to reduce safety hazards, it is necessary to carry out stress analysis of the oil and gas pipelines that run through tunnels. In this study, a stress analysis model of pipelines running through a tunnel was developed. On the basis of the finite element method, CAESAR II software was used to analyze the stress and displacement of a section of parallel oil and gas pipelines that run through tunnels and stress and displacement distribution laws were drawn from the analyses. A study of the factors influencing stress recommended that: (1) The buttress interval of the parallel oil and gas pipelines in a tunnel should be 12 m; (2) The angle of inclined pipelines should be no greater than 25°; (3) The stress of oil pipelines enhances more obviously than that of gas pipelines under earthquake action; (4) The average stress can be reduced by adopting “ladder” laying; and (5) Guide bend can be set at the tunnel entrance and exit in order to reduce the stress.

Helioseismic Investigation of Modeled and Observed Supergranule Structure

The subsurface structure of an “average” supergranule is derived using existing data products from the Helioseismic and Magnetic Imager (HMI) time–distance pipeline and compared to the best helioseismic flow model detailed by Duvall and Hanasoge (Solar Phys. 287, 71, 2013). We find that significant differences exist between them. Unlike the shallow structure predicted by the model, the average HMI supergranule is very extended in depth, exhibiting horizontal outflow down to 7 – 10 Mm, followed by a weak inflow reaching a depth of ≈ 20 Mm below the photosphere. The maximal velocities in the horizontal direction for the average supergranule are much lower than in the model, and its near-surface flow field RMS value is about an order of magnitude lower than the often-quoted values of ≈ 250 – 350 m s−1 for supergranulation. Much of the overall HMI supergranule structure and its weak flow amplitudes can be explained by examining the HMI pipeline averaging kernels for the near-surface inversions, which are found to be very broad in depth, and nearly identical to one another in terms of sensitivity along the z-direction. We also show that forward-modeled travel times in the Born approximation using the model (derived from a ray-theory approach) are inconsistent with measured travel times for an average supergranule at any distance. Our findings suggest systematic inaccuracies in the typical techniques used to study supergranulation, confirming some of the results of Duvall and Hanasoge (Solar Phys. 287, 71, 2013).

The need to extend the study of greenhouse impacts of mining and mineral processing to hydraulic streams: long distance pipelines count

Mining operations are major producers of greenhouse gases and energy consumers. Norgate and Haque (2010, 2012) make a strong point regarding the impact and the potential for reductions in energy consumption and greenhouse gas emissions in the mining industry. For the copper concentrate production, they have distinguished different sub-processes, including drilling, basting, loading & hauling, ventilation, dewatering, crushing & grinding, and concentration. They conclude that the loading & hauling stage is the mostenergy-intensive, and that the crushing & grinding stage has the highest potential for energy saving. Although notexactly featuring at the core of the production processes, ore concentrate transport might be an energy-intensive activity when sufficiently long slurry transport lines are installed. In several South American countries, including Chile, Brazil, Peru and Argentina, it is very common for ore concentrate plants to deliver copper, iron or bauxite concentrate through complex topographies connecting distances above 100 km (Jacobs, 1991; Derammelaere and Shou, 2002; Abulnaga, 2002; Santos et al., 2009). Taking into account inventory bases from USA, Australia and Canada, Table 3 in Norgate and Haque (2010) shows, for copper concentrate, an energy consumption of 140 MJ/t at the concentrating stage and 673 MJ/t for dewatering. When applicable, the aforementioned transport process fits between both. Recently, Ihle and Tamburrino (2012) identified specific energy consumptions due to slurry transport in the order of 0.5 MJ/(t km) for a 6 inch nominal diameter pipeline for a dry throughput of 36.7 kg/ s, or about 1.1 million tons per year with a 95% utilization rate. A similar result was obtained by Wu et al. (2010) using a 158 mm internal diameter loop in a laboratory facility. This gives an energy requirement in the order of 50 MJ/t per 100 km pipeline, which can actually reach about twice the value for many long distance concentrate pipeline operations, thus competing with other energy consumption items referred to in Norgate and Haque (2010). Here, there is also significant room for energy efficient design and operation (Ihle and Tamburrino, 2012), and embodied energy and greenhouse gas emissions need to be accounted for and optimized as well. In the particular case of the hydraulic transport of concentrates, it is also necessary to consider the relation between water requirements and energy consumption: less of a water implies less water footprint but, on the other hand, higher energy consumptions, greenhouse gas emissions and embodied energy associated with the final product, the concentrate. A question being pursued in research currently being undertaken by the author is what is the optimal balance between the different elements that minimize the overall environmental impact of new infrastructure and process.