API Phase Boundary Reference Database for Natural Gas Mixtures

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API Phase Boundary Reference Database forNatural
Gas Mixtures
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Previous 20.1 need

• Realistic phase data and uncertainties on for
  real complex fluid mixtures.
• Provide an experimental data base that is valid
  and can be applied to validate the performance
  characteristics of any phase models for complex
  fluid systems.
• Provide foundation physical property data.

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Overview

• Phase I provides background phase boundary data
  for natural gas mixtures. It provides basic phase
  data collection/compilation, data gap
  identification and recommendations for Phase II.
• Phase II was envisioned as an experimental
  measurement and data evaluation effort to fill
  realistic mixture phase boundary data gaps and
  establish complex mixture reference data
  uncertainty.
• Follow-up efforts were envisioned to support the
  implementation of the results in Chap. 20.1.

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Approach

• Apply the multi-component data development
  approach for phase boundary data that was used
  for the development of the real fluid density
  data base.
• The mixture data base is the foundation data of
  API 14.2/AGA8/GERG (ISO 12213/20765) models.

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Identified Target Uncertainties
Region IV
1.0
Region III
0.5
Region II
0.3
Region I
0.1
Custody Transfer Region
0
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Natural Gas Mixture Data Independent Laboratory
Z-Factor Measurements Pressure-Temperature
Conditions, Regions 1, 2, and 3
gt 20,000 Data Points
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NATURAL GAS MIXTURE Z DATA Data Sets vs.
Composition
Natural and some un-natural gas mixture data
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NATURAL GAS MIXTURE Z DATA Data Sets vs.
Composition
Reference natural gas mixture data
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Gulf Coast Gas Data Range
GRI Reference Gas Mixture
Traceable data
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Amarillo Gas Data Range
GRI Reference Gas Mixture
Traceable data
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Ekofisk Rich Gas Data Range
GRI Reference Gas Mixture
Traceable data
High CO2 Gas Data
GRI Reference Gas Mixture
GRI Reference Gas Mixture
High N2 Gas Data
Very Rich Gas Data / Critical Region Range
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Gulf Coast Related Field Mixtures
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Gas Phase Density Data

• Realistic
• Great data (lt 0.1 uncertainty)
• Very limited component range relative to phase
  boundary needs !

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Phase Boundary Reference Data

• Catalog phase boundary data for realistic
  multi-component systems and identify phase
  boundary data gaps for such systems.
• The multi-component mixture data are data that
  are similar to actual field/system/pipeline/proces
  s fluid data.
• Approach Subdivide the phase boundary data into
  categories with similar fluid component
  characteristics.
• Phase Boundary Data Fluid Categorization Groups
• LNG type fluid mixtures
• Dry gas type fluid mixtures
• Condensate/retrograde gas type fluid mixtures
• Volatile oil type fluid mixtures
• Black oil type fluid mixtures
• Subgroups characterized by data set component
  characteristics.
• e.g. aliphatics, aromatics, olefinics,
  diluents, acid gas, water, etc.
• Focus on data sets with detail composition
  analysis, not uncharacterized fluids.

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Phase Boundary Multi-component Data Sets

• GPA - 15 sets
• U.Mich 128 sets
• Gasunie (requested data release)
• Delft 2 sets
• SWRI 4 sets
• EffecTech 10 sets
• ARCO 2 sets
• GRI - 3 sets
• GERG

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Component Range of Data

• GPA - up to C10, (some C30)
• U.Mich - up to C13
• EffecTech up to C12
• SWRI up to C10
• Delft up to C16
• Gasunie up to Cx (assume C16)
• GRI up to C6
• Arco up to C10

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P,T Range for Realistic Multi-component Phase
Boundary Data
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Data Source Compositions
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Data Source Compositions (cont.)
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Multi-component data T,P range

• Survey
• Only allocation type data, i.e. composition data
  no dpt. or vle mixture data.
• Data gaps
• Composition data gaps (component range)
• T,P condition data gaps
• Data validation gaps i.e. independent data sets
  and analysis, quantifies the uncertainty of any
  measured data.
• Data property gaps

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Recommendations

• (1) a comparison of the experimental data
  compiled under Phase I should be made to single
  phase multi-component mixture data on relevant
  properties, e.g. density to establish uncertainty
  trends in the basic phase boundary data

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Recommendations

• (2) phase boundary and uncertainty targets should
  be considered by the industry

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Recommendations

• (3) a limited number of sets of reference quality
  mixture data should be obtained to establish
  phase boundary uncertainties for specific fluid
  categories, e.g. LNG mixtures with commingled
  systems

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Recommendations

• (4) reference data measurements should include
  multiple property measurements, e.g. dew point,
  density, sound speed, phase fractions and other
  properties of interest at and within the
  two/three phase regime

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Recommendations

• (5) component considerations should be extended
  to include fluids containing water, brines,
  hydrogen sulfide, and injected chemicals for
  fluid control.

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Status

• Draft final report prepared.
• Submission to API.
• Needs
• Per recommendations
• Define commingled fluid characteristics for Phase
  II multi-component fluid phase and property
  measurements to fill data gaps.

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Phase Boundary Reference Data

• Fluid Category LNG related systems
• LNG phase boundary mixtures LNG blends with
  commingled fluid mixtures.
• Status
• - Low T LNG VLE data exists uncertainty
  unknown.
• - No industry mixture phase data for LNG -
  commingled system.
• - LNG type mixture data with well defined
  commingled blends does not exist.
• Situation
• Commingled vle data gap.
• Need to define composition character of
  commingled systems.
• Impacts
• Fluid sampling, measurement, design, equipment
  selection, equipment maintenance, EOS tools and
  analysis, training, balances, allocation
  methodology/algorithms.
• Suggest
• Minimum of 3 LNG type reference mixtures w/
  independent duplicate measurements to validate
  the uncertainty of the data. Number of reference
  mixtures depends on composition characteristics
  of blended fluids suggest a moderate and rich
  fluid mixture.

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Industry Phase Boundary Reference Data

• Fluid Category Dry gas related systems
• Dry gas phase boundary gas mixtures Dry gas
  blends with commingled fluids.
• Status
• -Dry gas phase vle data exists uncertainty
  unknown.
• -Because of sampling and GC uncertainty existing
  data may be misclassified or inconsistent - TBD.
• -Dry gas data with well defined commingled
  blends does not exists.
• Situation
• Phase boundary data gas for commingled systems
  is likely needed.
• Need to define composition character of
  commingled systems.
• No surprises expected just need validation
  phase data to quantify data uncertainty.
• Impacts
• Fluid sampling, measurement, design, equipment
  selection, equipment maintenance, training, EOS
  tools and analysis, balances, allocation.
• Suggest
• Minimum of reference mixtures measured w/
  independent duplicate measurements to validate
  the uncertainty of the data. Number of reference
  mixtures depends on composition characteristics
  of blended fluids.

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Industry Phase Boundary Reference Data

• Fluid Category Condensate / retrograde related
  systems
• Condensate phase boundary mixtures - Condensate
  blends with commingled fluids.
• Status
• -Limited condensate vle data appears to exist
  data uncertainty unknown.
• -Condensate data with commingled blends does not
  exists.
• Situation
• -Should expand the existing condensate vle data
  base.
• -Need phase boundary data for condensates in
  commingled system.
• -Need to define composition character of
  commingled systems.
• -Need to quantify the uncertainty of existing
  condensate phase data.
• Impacts
• Fluid sampling, measurement, design, equipment
  selection, equipment maintenance, training, EOS
  tools and analysis, balances, allocation.
• Suggest
• Minimum of reference mixtures measured over
  reference fluid mixtures w/ independent duplicate
  measurements for measured phase data uncertainty
  validation. Number of reference mixtures depends
  on composition characteristics of blended fluids.