https://orcid.org/0000-0002-6744-2917
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ABSTRACT
The production and transport of sand from oil and gas wells into production and transport facilities results in flow assurance and structural problems. A critical operational issue is the erosion of oil and gas facilities by the suspended sand particles, particularly around flow diversions. This study investigated the effects of four key parameters, namely particle size, sand load, fluid velocity, and fluid density, on the rate of sand erosion in gas pipeline bends using DNV GL-RPO501 and Star CCM+ software package, a Computational Fluid Dynamics (CFD) tool developed by CD – adapco. Sand concentration and particle sizes both cause a linear increase in erosion rate. The particle sizes affected the location of maximum erosion. The single and mixture component gas densities showed an inverse linear and non-uniform relationship with erosion rate. The CFD models underpredicted erosion rates by about 90% compared to the experimental data. An exponential relation exists between the erosion rate and gas/sand velocity especially velocities above 10 m/s. The CFD method largely predicted more realistic values of erosion rate than the DNV GL-RPO501 due to some oversimplified assumptions made in the latter. The CFD tool however compared favorably with the DNV GL-RPO501 at high velocities. Both CFD and DNV GL-RPO501 models are recommended for erosion studies at higher fluid velocities, while the CFD modeling is better at lower velocities by incorporating drag and inertial forces which are important forces at low gas velocities. The particle and fluid velocity affected the sand erosion rate more than the other factors considered. However, future studies should consider modeling erosion rates under transient conditions and investigate the effects of various turbulence models. Different sand mixtures with various particle sizes and other gases such as CO2 should be considered.
Nomenclature
| Symbol | = | DescriptionUnit |
| EL | = | Actual surface thickness loss ratem/s |
| Re | = | Reynolds number- |
| C1 | = | Model geometry factor- |
| Cunit | = | Unit conversion factor from m/s to mm/year- |
| A, Apipe | = | Pipe cross-sectional aream2 |
| CFD | = | Computational Fluid Dynamics- |
| dp | = | Particle diameterm |
| dpc | = | Critical particle diameterm |
| D, ID | = | Pipe Internal Diameter/Fluid Internal Diameterm |
| F(α) | = | Particle impact-angle function- |
| FP | = | Pressure gradient forceN |
| FV | = | Virtual mass forceN |
| FG | = | Gravity forceN |
| FB | = | Buoyancy forceN |
| HV | = | Vickers hardnessHv |
| G | = | Acceleration due to gravitym/s2 |
| N | = | Velocity constant- |
| εvp | = | Volume of material removed by a single sand particlem3 |
| mp | = | Mass of the particleKg |
| K | = | Ratio of the vertical to the horizontal component- |
| Ψ | = | Ratio of the depth of contact to the depth of cut- |
| Up | = | Particle velocitym/s |
| Ue | = | Erosional velocityft/s |
| ρm | = | Fluid mixture densitykg/m3 |
| C | = | Empirical constant used in the API RP 14E- |
| API-RP | = | American Petroleum Institute Recommended Practice- |
| DVN GL-RP | = | Det Norske Veritas Germanischer Lloyd Recommended Practice- |
| E | = | Volumetric rate of wall lossm3/s |
| ṁp | = | Mass rate at which particles impinge on the target materialkg/s |
| γ=dp/D | = | Ratio of particle diameter to geometrical diameter- |
| ρf | = | Density of fluidkg/m3 |
| Uf | = | Velocity of fluidm/s |
| µf | = | Dynamic viscosity of fluidPa. s |
| Ref | = | Fluid Reynolds number- |
| µt | = | Turbulence viscosityPa. s |
| RSM | = | Reynolds stress model- |
| Rep | = | Particle Reynolds number- |
| ρp | = | Particle densitykg/m3 |
| Urp= Uf - Up | = | Relative particle velocitym/s |
| εT | = | Tangential restitution coefficient- |
| εN | = | Normal restitution coefficient- |
| αP | = | Particle impact angleRad |
| VG | = | Volume flow rate of gasm3/s |
| VP | = | Volume flow rate of particlesm3/s |
| ρG | = | Density of gaskg/m3 |
| ER | = | Erosion ratem/s |
| ρt | = | Density of erodent materialkg/m3 |
| G | = | Particle size correction factor- |
| At | = | Area of pipe exposed to erosionm3 |
| R Curvature | = | Radius of curvature given as Number of Internal Pipe Diameters. Reference of radius of curvature is center line of pipeM |
| β = ρp/ρm | = | Density ratio between particle and fluid- |
| G | = | Acceleration due to gravitym/s |
Highlights
Examined four key parameters that govern sand erosion rates in gas pipelines.
Fluid/sand particle velocity has a significant effect on the erosion rates of the gas pipeline.
Different proportions of mixtures of methane, ethane, and propane affect erosion rates differently.
Different models for erosion rates modeling have unique strengths under various conditions.
Disclosure statement
No potential conflict of interest was reported by the author(s).