Pipeline Simulation Research Articles

Integration of computational fluid dynamics simulation and statistical factorial experimental design of thick-wall crude oil pipeline with heat loss

The aim of this study was to explore the heat transfer behavior between convection and conduction in the thick wall crude oil pipeline with laminar unsteady state flow using integration of developed computational fluid dynamics model and statistical experimental design. The governing equations were employed to investigate the effects of wall thickness, wall thermal conductivity, surrounding heat transfer coefficient and ambient temperature on transport profile using statistical experimental design and to locate an origin point where wax precipitate in the pipeline (wax appearance distance) by using response surface methodology (RSM). A good agreement between the model and literature experimental data suggests that the proposed numerical scheme is suitable for simulating the transport profile in pipeline and predicting the phenomena for any other conditions. From the statistical analysis, it was found that, surrounding heat transfer coefficient and ambient temperature were the major effect parameters on the wax appearance distance.

Simulation of Elongated Bubbles in a Channel Using the Two-Fluid Model

This paper investigates the capability of the two-fluid model to predict the bubble drift velocity of elongated bubbles in channels. The two-fluid model is widely used in the oil and gas industry for dynamic multiphase pipeline simulations. The bubble drift velocity is an important quantity in predicting pipeline flushing and slug flow. In this paper, it is shown that the two-fluid model in its standard form predicts a bubble drift velocity of (similar to the shallow water equations), instead of the exact value of as derived by Benjamin[1]. Modifying the two-fluid model with the commonly employed momentum correction parameter leads to a steady solution (in a moving reference frame), but still predicts an erroneous bubble drift velocity. To get the correct bubble drift velocity, it is necessary to include the pressure variation along the channel height due to both the hydrostatic component and the vertical momentum flux.

Comparison study on the accuracy and efficiency of the four forms of hydraulic equation of a natural gas pipeline based on linearized solution

Linearization technique is an efficient and fast method for the natural gas pipeline simulation. In order to determine the optimal selection of basic variables which have advantages on both the accuracy and efficiency for linearization method, the present paper systematically researched on the four forms of hydraulic equations according to various selections of the basic variables for solving the hydraulic equations: pressure and mass flux combination (F1(p,m)), pressure and velocity combination (F2(p,w)), density and mass flux combination (F3(ρ,m)), density and velocity combination (F4(ρ,w)), and the efficiency as well as the accuracy is compared based on their linearizations. Through analyzing the numerical results, it can be concluded that F4(ρ,w) is the most efficient and easiest form to implement on a computer for solving hydraulic equations as natural gas simulation is based on linearization technique, while the calculation using F1(p,m) turns out to be the slowest one.

Simulation of pipeline in the area of the underwater crossing

The article studies stress-strain behavior of the main oil-pipeline section Alexandrovskoye-Anzhero-Sudzhensk using software system Ansys. This method of examination and assessment of technical conditions of objects of pipeline transport studies the objects and the processes that affect the technical condition of these facilities, including the research on the basis of computer simulation. Such approach allows to develop the theory, methods of calculations and designing of objects of pipeline transport, units and parts of machines, regardless of their industry and destination with a view to improve the existing constructions and create new structures, machines of high performance, durability and reliability, maintainability, low material capacity and cost, which have competitiveness on the world market.

Pipeline Energy Consumption Optimization: A Novel Power Optimization Utility Software

Today pipeline operators are required to balance operational efficiency, financial performance, and long-term sustainability. Transporting hydrocarbons efficiently and safely is a demanding task, and energy consumption is one of the major operating costs and sources of emissions. New applications based on pipeline simulation can contribute to reducing energy costs and optimizing operations while continuing to achieve the required delivery schedules within the safety and operating margins. This simulation-based approach considers the different energy costs across the pipeline pump/compressor stations, utility contracts, pump/compressor efficiency, and the costs and benefits of using drag-reducing agents (DRAs). It is a valuable tool that allows energy managers and pipeline operators to optimize energy costs. It can be seamlessly integrated into the supervisory control and data acquisition (SCADA) infrastructure, which provides the realtime views and reporting of all energy and process variables, including the cost savings achieved. The SCADA system monitors and controls one or more complete pipelines used for transporting liquid or gas products from one location to another. Each pipeline may be very long and may have several branches.

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Waxy oil gelation and rheology is investigated and modeled using strain-dependent viscosity correlations. Rotational rheometry shows a sharp viscosity increase upon gel formation. High creeping flow viscosities are observed at small deformation conditions prior to yielding. A new strain-dependent rheological model, following analogous formulation to the Carreau–Yasuda shear rate-dependent model, captures viscosity reduction associated with yielding. In addition, shear viscosity and extensional viscosity are investigated using a capillary rheometry method. Distinct shear-thinning behavior is observed in the shear mode of deformation, while distinct tension-thinning behavior is observed in the extensional mode of deformation for the model fluid systems. High Trouton ratios are obtained for the gelled model fluid systems, confirming strongly non-Newtonian fluid rheology. Finally, axial pressure wave profiles are computed at real pipeline dimensions for idealized moderate yield stress fluids using a computationally efficient 1D pipeline simulator. The Rønningsen time-dependent gel degradation model is used to emulate the fluid rheology in the simulator. Axial stress localization phenomena are shown to depend on the overall magnitude of gel degradation as established by the reduction in yield value. A high degree of gel degradation serves to afford flow commencement in a timely manner.

Welding Stress Numerical Simulation and Analysis of High-Pressure Pipeline

Welded stress has an important impact on quality and life of of high-pressure pipeline. Based on pipeline material performance, considered welding arc force and its mining action, selected double ellipsoidal heat source model, simulated welding process of of high-pressure pipeline, analysised welding temperature field and stress field, determined the distribution disciplines of welding stress, provides useful help on exploring the disciplines of pipeline welding.

Analysis of Suspended Pipeline Stress Sensitivity

Natural gas pipeline laying process will inevitably go through some of the earthquake-prone areas, these areas of soil subsidence, will cause the pipeline vacant, vacant section of the pipeline failure may cause pipeline rupture. Effects of suspended pipeline stress safety usually have two factors: suspended length and the buoyancy of water. In order to explore the sensitivity of these two factors on suspended pipeline stress, we do numerical simulation of XX suspended pipeline using the general stress analysis software CAESAR II. Research shows that suspended length of pipe is having a greater sensitivity on pipeline stress, and the buoyancy of water is relatively small. The results provide some reference for safety management and selection of pipeline.

Transient Analysis of a Complex Network of Gas Pipeline Compulsory in the Design by Dynamic Simulation

Technical and economical calculations of pipelines networks of are made currently on the basis of stationary flow regimes that are to say of working regimes where the technical features (mainly flow speed and pressure) are supposed non variants with regard to the time. However the analysis of practical situations shows that the real flows are only unusually stationary. The hypothesis of stationary aspect in the conception of pipeline networks is bound mainly to the mathematical difficulties describing the nonstationary out-flow in a complex network of pipelines: differential equation systems of non linear partial derivatives of very big dimension. However the analysis of practical situation shows that the real out-flows are only unusually stationary. We suggest in this subject a modelling and simulation of a real pipeline with variable and transient regime and to study by means of numerical simulations the dynamic behavior of gas in pipeline by means of several scenario. The software used is the SIMONE of LIWACOM Group s.r.o and TGNET 5.6- E of SSI.

Research of Emergency Venting Time in Natural Gas Pipeline Accidents with SPS

Gas venting is an important step in the emergency repair of natural gas pipeline accidents. Accurately estimating the gas venting time is of great significance for arranging gas pipeline emergency repair process. Therefore, the venting model is built with Stoner Pipeline Simulator (SPS), and the influencing factors of venting time are studied by SPS dynamic simulation. The results show that pipe length, pipe pressure, pipe diameter and diameter of gas venting pipe can affect the gas venting time. And then a empirical law of natural gas venting time and pipe parameters is summed up, which can provide theoretical support for the organization of emergency repair.

Research and Application on the Dynamic Simulation of Natural Gas Pipeline

Based on the fundamental flow equations of high-pressure gas pipeline, the numerical solution for unsteady-state flow was studied with the Central difference scheme. Considered the energy equation and urban gas regular, the problem of low calculation precision caused by ignorance of the energy equation was solved. During the variation of gas consumption with time, the dynamic simulation program was generated. Finally, a numerical example of engineering application was presented .

Dynamic simulation of subsea pipeline and trawl board pull-over interaction

This paper presents a novel strategy based on the finite element method for prediction of fishing gear interference loads on subsea pipelines. Trawl board pull-over interaction is addressed with emphasis on hydrodynamic load representation, handling of pipe-trawl contact and modeling of the trawl gear system. A validation study involving 34 model test runs was carried out for three trawl boards with variation of pipe span height, towing velocity, towing line stiffness and pipe support conditions. The simulated bias of the load impulse was found to be within a 10% margin of the model test measurements. Based on the validated numerical model a sensitivity analysis involving nearly 250 simulations was conducted. The interaction behavior was seen to be greatly influenced by the board-pipe friction coefficient, the tension level in the wire between board and trawl net, the towing line drag properties and the direction of over-trawling.

Technology Focus: Reservoir Simulation (July 2013)

Technology Focus Looking back through previous editions of this article, I note that, in 2011, I wrote, “there’s a growing tendency in some quarters to use very simple models.” That may be true, but there is also a growing tendency among vendors to offer models with more and more features. That is how they stay in business, after all, and many of the new features solve problems we have struggled with for years. The trouble, however, is sometimes a feeling that all those features have to be used at the same time. Let’s remind ourselves that a compositional model will never have as many components as there are distinct molecules in the reservoir fluid. The most sophisticated coupled pipeline simulator is still only an approximation of the complexity of fluid flow in pipes. Even the most advanced geomechanics simulator has a very coarse model of the over-, under- and sideburdens, and a crude approximation of often unknown boundary conditions. Building an exact model of the reservoir and production system is like seeking the end of the rainbow. Piling on complex features can easily mask critical issues. We should always strive to use the simplest model that captures the most important physics affecting the decision we are trying to make. And judging what is “the most important” physics is the responsibility of the reservoir engineer, not the software and not the software vendor. A simulation model is only a model. And our job is to produce the reservoir, not the model. Recommended additional reading at OnePetro: www.onepetro.org. SPE 159274 A Novel Simulation-Model Review Process by M.R. Palke, Ryder Scott Company, et al. SPE 159584 Dual-Continuum Modeling of Shale and Tight Gas Reservoirs by Prince N. Azom, The University of Texas at Austin, et al. SPE 162380 Application of Streamline Simulation to Reservoir Management: Management of WAG-Injection Optimization by Mohamed Bouaouaja, Schlumberger, et al. SPE 162045 Stochastic Uncertainty Analysis in Compositional Simulation for Giant-Gas/Condensate-Field Reservoir-Performance Prediction by E. Descubes, Schlumberger, et al. SPE 164142 Uncertainty-Quantification Workflow for Mature Oil Fields: Combining Experimental-Design Techniques and Different Response-Surface Models by Syed Jawwad Ahmed, ADNOC, et al.

Application of Statistical Analysis Techniques to Pipeline On-Bottom Stability Analysis

Offshore pipelines are increasingly being employed to transport offshore hydrocarbons to onshore processing facilities. Pipelines laid directly on the seabed are subject to a considerable hydrodynamic loading from waves and currents and must be accurately designed for on-bottom stability. Confidence in the stability of pipelines requires appropriate models for their assessment and, in this paper, particular emphasis is placed on achieving an integrated and balanced approach in considering the nonlinearities and uncertainties in the pipe structure, the reaction of the restraining soil, and the hydrodynamic loading applied. A statistical approach is followed by developing a response surface model for the pipeline maximum horizontal displacement within a storm, while including variability in parameters. The Monte Carlo simulation method is used in combination with the developed response surface model to calculate the extreme response statistics. The benefit of this approach is demonstrated and also used to investigate the sensitivity of the on-bottom pipeline simulation for a variety of model input parameters. These results provide guidance to engineers as to what uncertainties are worth reducing, if possible, before a pipe is designed.

Numerical Study on the Gas-Liquid Two Phase Flow in Pipeline Commissioning

Pipeline commissioning is a gas-liquid two phase flow process. In the hilly area, the complex flow status in pipeline may threaten the safety of the commissioning process. This paper developes a novel numerical technology to simulate the hydraulic process of pipeline commissioning. Several alternative modules are established, focused on which physical and mathematical models are established respectively to describe its flow status and corresponding pressure drop. With the aid of recognition technology and regulation and control technology, connection of these pipe sections can be performed to represent the actual pipeline and thus realizing the simulation of pipeline commissioning process.

The Dynamic Simulation of a Long Distance Natural Gas Pipeline

With the growth of the natural gas market, the long distance natural gas pipeline system is getting more and more important in nowadays. As a united and enclosed hydraulic system, the operation conditions of the whole line will be changed by the influence of the condition change in one station. On the one hand, the condition change made people analyze operation scheme more difficult, on the other hand, pipeline system operating conditions directly affect the relationship between the production and the sales of natural gas. Therefore, the operation of the gas pipeline must be optimized, which brings huge economic and social benefits. This paper constructed a simulation model of a long distance natural gas pipeline by TG.net, and then analyzed the change of the operating condition of the pipeline after a compressor station shut down, found out the regularity.

Absolute Roughness of Trunk Natural Gas Transmission Pipeline with Mechanics Properties and Material Properties

The absolute roughness of pipeline is of great importance on the process calculation of trunk gas transmission pipelines. The software package Pipeline Studio is used to build the West-to-East Gas Pipeline, the Second West-to-East Gas Pipeline, Shan-Jing Gas Pipeline and the Second Shan-Jing Gas Pipeline simulation models, and the pipe segment between the valve chambers is the minimum element. The pipeline absolute roughnesses are inverse calculated with using the simulation models and 38 groups of realistic operation parameters. The results show there is no significant association between the absolute roughness and seasons as well as flow rate. The absolute roughness of the trunk Gas Pipeline is about 0.240mm within one year after commissioning, and the absolute roughness of the trunk gas pipeline will be gradually reduced with the growth of the running time, and the roughness will maintain about 0.009-0.014mm after 3 years from commissioning.

Design of Long-Distance Pipeline Remote Monitoring System

This article describes the design of the long-distance pipeline system, then gives out the overall framework of the remote monitoring system consisting of server and client machine, the serial communication program design methods, and the functional modules of the client machine. After analyzing the pipeline simulation model the conclusion is made.

Transient Multiphase Flow: Past, Present, and Future with Flow Assurance Perspective

Historically, transient multiphase flow codes grew out of nuclear safety codes developed specifically to model nuclear plants during loss-of-coolant accidents (i.e., steam–water). These codes were heavily augmented by the oil and gas industry to deal with the more complex fluids, geometries, and thermodynamics associated with oil and gas production. Although several attempts were made to develop transient mixture models with a single momentum equation, development settled on two-fluid formulations, employing separate momentum equations for each phase (developed out of a force balance), as the best way forward. While such models were quite successful in simulating holdup and pressure drop during both steady-state and transient operations, many associated flow assurance issues (i.e., hydrates and hydrodynamic slugs) remain quite rudimentary. Also, the simulators themselves are terrifically slow by general computational fluid dynamics (CFD) standards. In the future, simple, powerful mixture models may well make a comeback, supplanting the more complex two-fluid models. The rationale is 3-fold: First, the simplicity of these models will allow for much greater computational speed, resulting in the possibility to run much finer grids (on the order of a pipeline diameter) than currently used by transient pipeline simulators. Second, compositional tracking could be routinely used, allowing for much simpler simulations of, for example, complex networks of differing fluids. Third, flow assurance phenomena, such as hydrate formation, could be folded directly into the multiphase model on a fundamental level rather than as an ad hoc addition.

Dynamic simulation of pipelines containing dense phase/supercritical CO2-rich mixtures for carbon capture and storage

Carbon dioxide mixtures from separation plants contain usually some impurities. Major impurities include nitrogen, argon, hydrogen and oxygen, depending on the capture technology used for the removal of CO2. The mixture composition determines the critical point data, and the values of critical pressure and critical temperature define, in turn, the limits of dense phase/supercritical pipeline operating conditions. The simulation of dynamic behaviour of three dense phase/supercritical CO2-rich mixtures was carried out in this study. The pipeline CO2 flow model was formulated with the assumption of one-dimensional, nonisothermal flow condition. An illustration of the performance of the model by an example of a fictive but realistic onshore CO2 pipeline is given. The results show that the type and quantity of impurities have a significant influence on the hydraulics of the pipeline transportation system under transient conditions. They also indicate that the transportation costs vary and are dependent on the capture technology used.