Journal of Pipeline Science and Engineering最新文献

The slurry erosion processes of horizontal elbows are investigated numerically using an Eulerian-Lagrangian method coupled with particle rebound and erosion model. First, a mechanical model for the internal multiphase flow involving slurry erosion in the 90° horizontal elbow is established and the corresponding governing equations are presented. Then, a two-way coupled numerical solution procedure is developed and its accuracy and stability are examined carefully using benchmark pipe flow models with experimental results. Using the validated numerical methods, the effects of flow velocity, fluid density and fluid viscosity on the flow and slurry erosion in the horizontal elbow are analyzed in detail. Finally, a prediction method of erosion rate distribution based on the pipe Froude number, particle Stokes number and the Dean number is proposed. In this method the pipe Froude number is employed to qualify the effect of ununiform distribution of particles, particle Stokes number and Dean number are combined to qualify the effects of inertia force, drag force and secondary flow. Using this approach, the location of the maximum erosion rate in horizontal elbows under different operating conditions can be predicted more conveniently.

The uplift capacity of pipeline systems in geotechnical engineering is influenced by internal loading and external factors, making it a significant consideration in pipeline design problems. Previous research has conducted experimental tests and numerical solutions to investigate the relationship between force and displacement or the resistance of pipelines in numerous soil media. This paper proposes a machine-learning regression technique to predict the uplift capacity of buried pipelines in anisotropic clays with parametric analysis. Specifically, the Multivariate Adaptive Regression Spline (MARS) is employed to establish the relationship between input parameters, namely the depth ratio (H/D), anisotropic strength ratio (r_e), load inclination (β), overburden factor (γH/S_uc), adhesion factor (α), and the output uplift resistance (N) obtained from the finite element limit analysis (FELA), utilizing the AUS material model integrated with the OptumG2 commercial program. Furthermore, the sensitivity analysis outcome shows the embedded depth ratio is the most critical parameter, followed by the anisotropic strength ratio, overburden factor, load inclination, and adhesion factor. Additionally, the shear velocity field contours show that when the depth ratio and the load inclination increase, the dissipation of shear changes. Design data visualizations, tables, graph contours, and empirical equations are created and can be utilized to aid in the development of practical designs.

In the early stage of pipeline network reform in China, it is still controversial to formulate an appropriate pipeline freight pricing strategy. Focusing on this issue, this paper puts forward an integrated framework to analyze the impact of different pipeline pricing strategies on the economic-environmental benefits of China’s oil product logistics. A basic mathematical programming model is developed to simulate the planning of nationwide oil product logistics at the tactical level. On this basis, five pipeline pricing strategies are customized for comparative analysis, including pricing as usual (PAU), pricing by benchmarking railway (PBR), pricing by discounting on excess (PDE), tiered pricing by mileage (TPM), and tiered pricing by volume (TPV). Then, the basic logistics optimization model is upgraded accordingly. The real-world case study in China in 2019 is carried out in detail and the results demonstrate that (i) Except for TPM, the other pricing strategies can achieve coordination between oil shippers and pipeline carriers compared with PAU; (ii) Ranked by economic performance as follows: PDE >PBT>TPV> PAU>TPM; (iii) As for PDE, it also helps to reduce carbon emissions by 0.5% annually. The proposed method can be a theoretical guide for oil and gas logistics managers and decision-makers within and beyond China.

Surfactant corrosion inhibition performance in water–oil environments is influenced by complex relationships between their physical properties, solution chemistry and interfacial characteristics. The existence of polar heads/nonpolar tails influences both the preferential distribution of the surfactant between the two media as well as the phase in which micellisation occurs. Both phenomena affect the efficiency of the surfactant inhibitor and its adsorption at the metal-solution interface. To demonstrate the complexity of such interactions, the effect of brine salinity on the critical micelle concentration (CMC) and partitioning/distribution behaviour of a quaternary amine corrosion inhibitor (alkyldimethylbenzylhexadecylammonium chloride, or BAC-C₁₆) in a brine and toluene system (at 1:1 ratio) was explored. All experiments were conducted at 50 °C and pH4 over varying salinities (0.1, 1 and 10 wt%) of NaCl brine. Both CMC and partitioning characteristics of BAC-C₁₆ are significantly affected by aqueous phase salinity, with an inversion of the partitioning response observed between concentrations of 0.1 and 1 wt% NaCl. The effect of BAC-C₁₆ partitioning/distribution behaviour on corrosion inhibitor performance was examined using rotating cylinder electrode experiments. The results illustrate that in order to establish the true corrosion inhibition behaviour, consideration of the chemical distribution characteristics is crucial.

Batch scheduling is a crucial part of pipeline enterprise operation management, especially in the context of market-oriented operation. It involves 3 main tasks: quickly preparing batch plans, accurately tracking interface movement, and operation condition in real time. Normally, the completion of multi-product pipeline batch scheduling depends on simulation models or optimization models and corresponding conventional solving algorithm. However, this approach becomes inefficient when applied to large-scale systems. The rapid development of machine learning has brought new ideas to batch scheduling research. This paper first reviews the current state of batch scheduling technology, and suggests that applying machine learning to it is a promising development direction. Then, we summarize the progress of machine learning applications in batch planning, interface movement tracking, and operational condition monitoring, and point out their limitations. Finally, considering the separation of refined oil production, transportation, and sales processes, 5 recommendations are put forward: oil supply and demand prediction and pipeline capacity prediction, batch planning, batch interface movement tracking, mixed oil development monitoring, and pipeline operation condition identification.

It is of paramount importance to ensure the safe operation of energy pipelines for pipeline owners and operators. Therefore, effective condition assessment of pipelines is imperative. For this purpose, there are a great number of models developed using various techniques. How to select a modeling approach and associated techniques to get the most of the effectiveness of the model under a condition with limited monitoring data and experience remains a big concern to pipeline operators.

This paper provides a comprehensive review of the developed approaches and techniques for energy pipeline degradation condition assessment. The primary motivation behind this review is the pivotal role of condition assessment in energy pipeline integrity management and the proliferation of models and techniques, including statistical modeling, stochastic processes, machine learning, and deep learning, used for assessing pipeline degradation. This work aims to identify and assess the challenges and gaps inherent in the utilization of these condition modeling approaches. By systematically analyzing the current state of research and practice, this review not only highlights the strengths and limitations of various modeling approaches but also offers insights into future opportunities for enhancing the research and management practice in the field of pipeline integrity management.

Our analysis offers valuable insights for researchers, practitioners, and policymakers in the domain of pipeline integrity management. It facilitates a better understanding of the complexities and intricacies of condition assessment, ultimately contributing to the development of more robust and effective strategies for safeguarding the integrity of energy pipelines.

To investigate the influence mechanism of the annealing treatment on the intermolecular action of waxy crude oil, this study selected the molecular models of oil, wax, resin and asphaltene, and constructed the model system to imitate instead of the waxy crude oils by using the Materials Studio software, and revealed the influence mechanism of annealing treatment. Three main findings were made: 1) The basic molecular unit structure is the premise of phase transformation, and the different annealing times are the main factors affecting the phase transformation. 2) After annealing treatment, the conformation of molecular chain gradually changes from the initial straight chain to the curly state, and the change is most obvious at the lowest energy; in terms of system energy, the changes of E_val, E_non-bond and E_total of the three oil samples all increase in different extent during the whole thermal process. 3) In terms of the radial distribution function (RDF) between the identical types of molecules and heterogeneous molecules of waxy crude oil, the accumulation of asphaltenes plays a leading role in the annealing process of waxy crude oil system, and the van der Waals force is the main force.

Polyethylene (PE) pipes are widely used for natural gas distribution due to their good durability and low costs. To ensure the integrity of PE pipelines, it is crucial to develop a comprehensive understanding of pipe failure mechanisms and to recognize the benefits and limitations of different pipeline monitoring strategies. This review provides an overview of different types of pipe failures in the context of their response to operational loads and material degradation. It also covers the details of mechanical tests for predicting the long-term performance of pipes, theoretical models for studying defect growth, examines different defect detection methods, and concludes with an assessment of pipe repair techniques. The findings highlight the importance of investigating the effects of existing defects on the operational performance of the pipeline. This indirectly emphasizes the need to develop time- and cost-efficient strategies to detect defects in the early stages. There is a clear gap in the inclusion of PE aging effects in the lifetime performance models. In addition, given the large number of inspection techniques, a regulated selection of pipeline inspection methods is highly desired, specific to the defect type. Further research in advancing adhesive-based repair of incipient defects is crucial to prevent catastrophic defect growth.

A recent study on active trapdoor stability has been completed by the authors using Terzaghi's three stability factors approach. It was concluded that the superposition approach is an effective way to evaluate the stability of cohesive-frictional soils. This technical note aims to extend the previous active trapdoor study to perform a stability assessment of a passive planar trapdoor (i.e., a blowout condition) in cohesive-frictional soil. Note that this passive trapdoor problem represents the blowout stability of soils due to defective pipelines under high water main pressures, in spite of the frequent media news about the water main bursts which enlightens the relevance of the problem. Numerical solutions of upper and lower bound finite element limit analyses are presented in form of the three stability factors (F_c, F_s, and F_γ), which consider the effect of cohesion, surcharge, and soil unit weight respectively. In the event of passive trapdoor stability, this technique can be used to determine a critical blowout pressure due to a water mains leak. The study continues with a series of sensitivity analyses with a widely selected range of parameters including the cover-depth ratio (H/B) and the drained frictional angle (ϕ). The influence of these parameters on the three stability factors is discussed, and a practical example of adapting these approaches is also introduced. All numerical results are provided in the forms of design charts and tables that can be efficiently used with confidence in design practice.

Blending hydrogen in existing natural gas pipelines compromises steel integrity because it increases fatigue crack growth, promotes subcritical cracking and decreases fracture toughness. In this regard, several laboratories reported that the fracture toughness measured in a hydrogen containing gaseous atmosphere, K_IH, can be 50% or less than K_IC, the fracture toughness measured in air. From a pipeline integrity perspective, fracture mechanics predicts that injecting hydrogen in a natural gas pipeline decreases the failure pressure and the size of the critical flaw at a given pressure level. For a pipeline with a given flaw size, as shown in this work, the effect of Hydrogen Embrittlement (HE) in the predicted failure pressure is largest when a failure occurs by a brittle fracture. The HE effect on failure pressure diminishes with a decreasing crack size or increasing fracture toughness. The safety margin after a successful hydrostatic test is reduced and therefore the time between hydrotests should be decreased. In this work, all those effects were quantified using a crack assessment methodology (level 2, API 579-ASME FFS) considering literature values for K_IH and K_IC reported for an API 5L X52 pipeline steel. To characterize different scenarios, various crack sizes were assumed, including a small crack with a size close to the detection limit of current in-line inspection techniques and a larger crack that represents the largest crack size that could survive a hydrotest to 100% of the steel Specified Minimum Yield Strength (SMYS). The implications of a smaller failure pressure and smaller critical crack size on pipeline integrity are discussed in this paper.