Transients in Gas-Condensate Natural Gas Pipelines

1998 ◽  
Vol 120 (1) ◽  
pp. 32-40 ◽  
Author(s):  
J. Zhou ◽  
M. A. Adewumi
Keyword(s):  
Natural Gas ◽  
Phase Behavior ◽  
Hydrodynamic Model ◽  
Fluid Dynamic ◽  
A Priori ◽  
Gas Condensate ◽  
Behavior Model ◽  
Two Phase ◽  
Natural Gas Pipelines ◽  
Natural Gas Transmission

Liquid condensation in natural gas transmission pipelines commonly occurs due to the thermodynamic and hydrodynamic imperatives. Condensation subjects the gas pipeline to two-phase transport. Neither the point along the pipeline at which the condensate is formed nor the quantity formed is known a priori. Hence, compositional multiphase hydrodynamic modeling, which couples the multiphase hydrodynamic model with the natural gas phase behavior model, is necessary to predict fluid dynamic behavior in gas/condensate pipelines. A transient compositional multiphase hydrodynamic model for transient gas-condensate two-phase flow in pipelines is presented. This model consists of our newly developed well-posed modified Soo’s partial pressure model in conservative form which serves as the transient multiphase hydrodynamic model, and the phase behavior model for natural gas mixtures.

Evaluation of “Marching Algorithms” in the Analysis of Multiphase Flow in Natural Gas Pipelines

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Luis F. Ayala ◽  
Doruk Alp
Keyword(s):  
Natural Gas ◽  
Multiphase Flow ◽  
Fluid Dynamic ◽  
Standard Technique ◽  
Rate Of Change ◽  
Entire Length ◽  
Governing Equations ◽  
Two Phase ◽  
Natural Gas Pipelines ◽  
Common Technique

Marching algorithms are the rule rather than the exception in the determination of pressure distribution in long multiphase-flow pipes, both for the case of pipelines and wellbores. This type of computational protocol is the basis for most two-phase-flow software and it is presented by textbooks as the standard technique used in steady state two-phase analysis. Marching algorithms acknowledge the fact that the rate of change of common fluid flow parameters (such as pressure, temperature, and phase velocities) is not constant but varies along the pipe axis while performing the integration of the governing equations by dividing the entire length into small pipe segments. In the marching algorithm, governing equations are solved for small single sections of pipe, one section at a time. Calculated outlet conditions for a particular segment are then propagated to the next segment as its prescribed inlet condition. Calculation continues in a “marching” fashion until the entire length of the pipe has been integrated. In this work, several examples are shown where this procedure might no longer accurately represent the physics of the flow for the case of natural gas flows with retrograde condensation. The implications related to the use of this common technique are studied, highlighting its potential lack of compliance with the actual physics of the flow for selected examples. This paper concludes by suggesting remedies to these problems, supported by results, showing considerable improvement in fulfilling the actual constraints imposed by the set of simultaneous fluid dynamic continuum equations governing the flow.

A Unified Two-Fluid Model for Multiphase Flow in Natural Gas Pipelines

2002 ◽  
Author(s):  
Luis F. Ayala ◽  
Eltohami S. Eltohami ◽  
Michael A. Adewumi
Keyword(s):  
Natural Gas ◽  
Hydrodynamic Model ◽  
Fluid Model ◽  
Liquid Loading ◽  
Two Phase ◽  
Natural Gas Pipelines ◽  
Fluid Velocities ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Equilibrium Calculations

A unified two-fluid model for multiphase natural gas and condensate flow in pipelines is presented. The hydrodynamic model consists of steady-state one-dimensional mass and continuity balances for each phase and a combined energy equation to give a system of five first-order ordinary differential equations. The hydrodynamic model is coupled with a phase behavior model based on the Peng-Robinson equation of state to handle the vapor-/liquid equilibrium calculations and thermodynamic property predictions. The model handles single and two-phase flow conditions and is able to predict the transition between them. It also generates profiles for pressure, temperature, and the fluid velocities in both phases as well as their holdups. The expected flow patterns as well as their transitions are modeled with emphasis on the low liquid loading character of such systems. The expected flow regimes for this system are dispersed liquid, annular-mist, stratified smooth as well as stratified wavy.

Assessment of Non-Equilibrium Phase Behavior Model Parameters for Oil and Gas-Condensate Systems by Laboratory and Field Studies (Russian)

2020 ◽  
Author(s):  
Ilya Mikhailovich Indrupskiy ◽  
Mikhail Yurievich Danko ◽  
Timur Nikolaevich Tsagan-Mandzhiev ◽  
Ayguzel Ilshatovna Aglyamova
Keyword(s):  
Phase Behavior ◽  
Oil And Gas ◽  
Equilibrium Phase ◽  
Field Studies ◽  
Gas Condensate ◽  
Model Parameters ◽  
Behavior Model ◽  
Non Equilibrium

Economic Evaluation Technique of Selecting Turbines for Natural Gas Pipelines

1978 ◽  
Author(s):  
T. E. Hajnal
Keyword(s):  
Economic Evaluation ◽  
Natural Gas ◽  
Operating Costs ◽  
Evaluation Technique ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Pipeline Systems ◽  
Natural Gas Transmission ◽  
Transmission Pipeline ◽  
Type Size

Designers of natural gas transmission systems often have to make recommendations as to the type, size, and number of turbines to be purchased and installed either on new pipelines or on expanding existing systems. This paper describes the economic evaluation technique which is being used by TransCanada PipeLines, of selecting turbines for natural gas transmission pipeline systems. The technique is based on comparing the present worths of annual owning and operating costs associated with the turbines considered for installation.

Experimental study of the weld microstructure properties in assembling of natural gas transmission pipelines

2015 ◽  
Vol 231 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
M Sabokrouh ◽  
SH Hashemi ◽  
MR Farahani
Keyword(s):  
Mechanical Properties ◽  
Natural Gas ◽  
Chemical Analysis ◽  
Structural Integrity ◽  
Optical Microscope ◽  
Microalloyed Steels ◽  
Chemical Compositions ◽  
Natural Gas Pipelines ◽  
Natural Gas Transmission ◽  
Girth Welds

The coexistence of high levels of strength and toughness is necessary for the microalloyed steels used in natural gas pipelines. The welding thermal cycle can significantly change the microstructures and therefore the mechanical properties of the girth welded pipelines. Thus, the experimental investigation on the welded material properties is required for assessing the structural integrity of the pipelines. In this article, the metallurgical characteristics of the multi-pass girth welds on API X70 steel pipes with 56 in outside diameter and 0.780 in wall thickness were determined for the first time using chemical analysis and standard metallography. The chemical analysis showed different chemical compositions in different weld passes. The amount of carbon in the weldment increased in comparison with the base metal, although the microalloy elements in the weld gap decreased by increasing the pass number. The metallographic investigation by optical microscope demonstrated the different microstructures in different sub-zones of the welded joint. The images obtained from scanning electron microscope also presented the dendritic and acicular structures in the root and cap passes, respectively. The observed hard phases in the weldment, such as martensite, had direct effects on the mechanical properties of the weldment and heat-affected zone.

Analysis of Transient Gas-Liquid Two-Phase Flow in Pipelines

1988 ◽  
Vol 110 (2) ◽  
pp. 93-101 ◽  
Author(s):  
K. Kohda ◽  
Y. Suzukawa ◽  
H. Furukawa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Air Flow ◽  
Water Flow Rate ◽  
Mass Conservation ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Conditions ◽  
Natural Gas Pipelines

A new method is developed to analyze transient gas-liquid two-phase flow in natural gas pipelines. This method utilizes the two velocity mixture model to derive the basic equations. Also, a new model, which expresses phase conditions for multicomponent natural gas-condensate system, is presented to derive mass conservation equations for each hypothetical component. Transient air-water two-phase flow experiments were conducted using a test pipeline 105.3 mm in diameter and 1436.5 m long. Experimental conditions include, increasing or decreasing air flow rate with constant water flow rate, and transition from single-phase air flow to air-water two-phase flow. Experimental data were compared with calculated results, and the agreement was very good. Furthermore, calculated results agreed very well with a published field data.

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