Scale Flow Assurance Workflows in Multiphase Flow...
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Scale Flow Assurance Workflows in Multiphase Flow Simulation Mack Shippen - Schlumberger PIPESIM Product Champion OLI Simulation Conference November 17, 2010
Transcript of Scale Flow Assurance Workflows in Multiphase Flow...
Scale Flow Assurance Workflows in Multiphase Flow SimulationMack Shippen - SchlumbergerPIPESIM Product Champion
OLI Simulation ConferenceNovember 17, 2010
Abstract
Multiphase flow simulation is critical to the understanding of impact of flow assurance issues on oilfield production system design and operation. While the modeling of organic solids such as hydrates, waxes and asphaltenes has in recent years become commonly available in multiphase flow simulators, detailed modeling of inorganic scales has been regarded as a more specialist discipline due to the inherent complexities of water chemistry. Consequently, scale prediction methods currently available in upstream multiphase flow simulators are quite simplified. As scaling behavior for a given fluid is governed by the prevailing pressures and temperatures, accurate prediction of the occurrence, location and severity of scaling depends on accurate modeling of the pressure and temperature profiles along the complete production system. This work aims to combine state-of-the-art scale prediction models with state-of-the-art multiphase flow and heat transfer simulation technology to better understand scaling behavior and quantify risks in performing flow assurance studies. A workflow is presented which describes the coupling of the scale model with multiphase flow simulation and presents an example case study to illustrate the benefits of this approach.
Overview
Background – Multiphase Flow SimulationMechanism of ScaleChem – PIPESIM WorkflowCase StudySummary and Future Work
Overview
Background – Multiphase Flow SimulationMechanism of ScaleChem – PIPESIM WorkflowCase StudySummary and Future Work
Total Production System
Completion
Choke
Safety Valve
Tubing
Flowline
Pump
CompressorSeparator
Export lines
Riser
Reservoir
gas
oil
ΔP3 = PUSV – PDSV
ΔP1 = PR – Pwfs
ΔP6 = PDSC – PRB
ΔP8 = Psep – PCD
ΔP10 = PCD – PGD
ΔP11 = PPD – PLD
ΔP4 = Pwf – Ptf
ΔP7 = PRB – PsepΔP9 = Psep – PPD
Pressure Loss in System
•Flow in porous media•Multiphase Flow in pipes•Chokes/restrictions•Pumps/Compressors
ΔT1 = TR – Twfs
ΔT5 = Ttf – TDSC
ΔT6 = TDSC – TRB
ΔΤ10 = TCD – TGD
ΔΤ11 = TPD – TLD
ΔT4 = Twf – Ttf
ΔT7 = TRB – Tsep
Temperature Changes in System
•Convection (free, forced)•Conduction•Elevation•Radiation•JT Cooling/Heating•Frictional Heating
Segmentation
Node taken at Bottom Hole model reservoir to separator
Pwf PR
Inflow = PR – Pwf
Psep
Outflow = Pwf – Psep
Nodal Analysis
OutflowInflow
PR
PR
Psep
PsepPwf
Pwf
Flowrate
Nodal Analysis
Overview
Background – Multiphase Flow SimulationMechanism of ScaleChem – PIPESIM WorkflowCase StudySummary and Future Work
PVT File Structure
•Mass Fraction against total composition •Density•Viscosity•Heat Capacity•Enthalpy•Entropy•Thermal Conductivity•Compressibility factor•Surface tension against gas phase•Interfacial tension against other liquid phase•Molecular Weight
•Liquid 3•Water ice•Hydrate type 1•Hydrate type 2•Wax•Asphaltene•Scale total•Scale species 1•Scale species 2•Scale species…
•Mass Fraction•Density•Thermal Conductivity•Phase appearance curves•Etc.
•Gas•Hydrocarbon liquid •Aqueous liquid
Vapor/Liquid Phases Solid Phases (Optional)
V/L Phase Properties
Solid Phase Properties
Fluid Property File Generation
ScaleChem PIPESIM
PVT Tables
PVT Calculations – Loose vs. Tight
LooseAdvantages
Fast Simple to Implement
TightAdvantages
More accurate Can mix fluidsCan sensitize on fluid properties (eg. watercut)
Overview
Background – Multiphase Flow SimulationMechanism of ScaleChem – PIPESIM WorkflowCase StudySummary and Future Work
Case Study
Fluid Composition
Component Mol %Carbon Dioxide 2.7Methane 34.6Ethane 7.0Propane 6.5Isobutane 1.5Butane 4.1Isopentane 1.9Pentane 2.6Hexane 3.6C7+ 35.5
C7+ BP 344ºFC7+ MW 283
Species mg/LCationsNa+ 20,400 K+ 402 Ca++ 20 Mg++ 829 Ba++ 1 NH4+ 104 AnionsCl‐ 37,000
SO4‐‐ 20 HCO3‐ 715
Watercut 50 %Gas‐Oil Ratio 640scf/STB
Hydrocarbon WaterStock Tank Properties
Phase Envelope
Nodal Analysis
Tubing ID = 3 1/2”
Tubing ID = 2.41”
Skin = 0.7
Skin = 10
Phase Envelope
Phase Envelope 2
Pressure-Temperature Profile
Nodal Analysis – Possible Scale Impact
Tubing ID = 1.4”
Tubing ID = 2.9”
Skin = 0.7
Skin = 10
Results Available
Phase Envelope– Scale Appearance Lines (Total & by species)Profile Plots– Total Scale Mass Fraction (eg. ppm, mg/L)– Scale Species Mass Fraction– Scale Species Pre- and Post- Scale IndexSystem Plots– Max. Scale Mass Fraction/branch– Max. Pre-Post Scale Index/branch
Overview
Background – Multiphase Flow SimulationMechanism of ScaleChem – PIPESIM WorkflowCase StudySummary and Future Work
Summary
ScaleChem-PIPESIM workflow leverages complex water chemistry analysis and rigorous multiphase flow simulationCan be used to predict occurrence, location and severity of scale precipitation for entire production systemAvailability:– ScaleChem ?– PIPESIM 2011 – Summer 2011
Future work
Tight coupling at engine levelInput for pipe corrosion calculationsBlack Oil scale analysis?
Questions?
