EORI Low Salinity Research Program

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EORI Low Salinity Research Program
Update on Progress July 2008

• Geoffrey Thyne and Mark Leslie
• Enhanced Oil Recovery Institute
• University of Wyoming

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Outline

• Low Salinity Theory and Prediction
• Low Salinity Water Flooding Goals
• Planned Laboratory Projects

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Tensleep rock, Minnelusa brine and oil, CBM flood
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Low Salinity Theory and Prediction

• The response of crude oil/brine/rock
  combinations to injection of low salinity brine
  can not be predicted. At the present state of
  knowledge laboratory screening prior to field
  testing is essential (Zhang and Morrow 2006).
• One or more of the proposed mechanisms can be
  verified and used to develop a general model.

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Low Salinity Water Flooding Goals

• Evaluate potential for low salinity flooding in
  Wyoming reservoirs.
• Develop laboratory capability to test individual
  reservoirs and perform related experiments.
• Form partnerships with producers that have
  favorable potential for field trials.

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Low Salinity Water Flooding Goals

• Evaluate potential for low salinity flooding in
  Wyoming reservoirs
• Review all relevant literature
• Evaluate past experience in Wyoming
• Develop screening and scoping tools
• Develop process-based predictive model

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Preliminary Project Schedule
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Preliminary screening for low salinity in Wyoming
based on review of published work

• Sandstone with low clay content
• High salinity reservoir water
• One scenario would be -
• Use Powder River Basin CBM produced water TDS
  of 1500 ppm
• Best results with 100X difference in salinity
  (meaning reservoir TDS of 100,000 150,000)

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Identify potential candidate reservoirs/fields

• Confine choices to PRB
• Identify top six producing reservoirs (2007)

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17 Minnelusa Fields TDS gt 100,000 Cumulative
production gt 1Mbbls
Successful Lab results will trigger contact with
producers
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Planned Laboratory Projects

• Systematic set of batch experiments for most
  likely Wyoming fields.
• Systematic set of core floods for most likely
  Wyoming fields (test specific response and
  provide data for model).

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Laboratory Setup Schematic
Back-pressure regulator
Pump
Sample Separator
Oil sample
Water sample
Core
Transfer Vessel
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EORI Mass balance approach measure all influent
and effluent constituents.

• Measure influent and effluent components and
  study differences.
• Core (SEM, EXDA, XRD, petro).
• Crude oil (SARA trace metals).
• Brine cations (Ca, Mg, Na, K, Fe).
• Brine anions (Cl, SO4, HCO3).
• Flow-thru cell pH, specific conductance, TDS.
• Inorganic tracer (e.g., Br-)
• Organic tracer (?)

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Input data to preliminary geochemical model
(Geochemists Workbench).

• Coreflood data used in model for all reactions
  between oil/rock/water
• Ion exchange
• Precipitation-dissolution
• Partitioning (Kds) of oil and water components
  to rock
• Transport of brine and oil relative to
  conservative tracer

May modify commercial multiphase flow model if
required
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Low Salinity Laboratory

• Perform batch experiments to determine
  partitioning between water-rock-oil system
• Perform water-only floods to determine effects on
  rock and flow properties caused by change in
  salinity.

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Secure core samples from potential candidate
reservoirs/fields
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Secure oil and water samples/analyses- from
potential candidate reservoirs/fields
Oil and water samples from Raven Creek Field, PRB
sample courtesy of Citation OG Corp.
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Low Salinity Laboratory Protocol

• Fully characterize the pre-flood reservoir rock -
  mineralogy, porosity and permeability (SEM, XRD,
  thin section, tracer studies, por-perm. CEC, BET).

Casper
Tensleep
Berea
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Analysis of water from potential candidate
reservoirs/fields and lab experiments
Low Salinity Laboratory Protocol
Effluent Water Samples Extract Effluent Water
with CH2Cl2 to remove organics Cations by
ICP Anions by IC Concentrate CH2Cl2extract and
analyze for organics by GC/MS

• Original Reservoir Brine and
• Original Low Salinity Brine
• Cations by ICP
• Anions by IC

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Low Salinity Laboratory Protocol

• Fully characterize the pre-flood reservoir oil -
  acid/base, GCMS, SARA, metals, (contract with
  WRI)

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Questions?