Low Salinity Water Injection Case study Heidrun Field

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Low Salinity Water Injection Case study
Heidrun Field
Classification Internal
Status Draft

• FORCE Seminar 15th May 2008
• Einar Hegre, StatoilHydro

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Outline

• Experimental results
• Background information Heidrun Field
• Heidrun Water injection system
• Upsides in addition to EOR?
• Challenges/obstacle for applying Low Salinity
  Water Injection on NCS?
• Way forward

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Water flood results for various outcrops using HD
STO at reservoir temperature
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U.Tilje well pattern
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SEAWATER
LOW SULPHATE WATER
PRODUCED WATER
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The water injection system
Present
Near future

• Near future
• Installation of additional PWRI pump
• Increased well flexibility, possible to inject
  PWRI to B and C template

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Technical Feasibility Study The study scope was
to evaluate

• Whether the existing sulphate removal package
  (SRP) can be converted to remove both the
  sulphate salts and reduce the total salinity
• The possibility to produce low salinity water on
  the Heidrun platform using reverse osmosis (RO)
• The possibility to place a RO pilot plant on
  Heidrun
• Evaluation is to be made for water with salinity
  in the range of 500-3000 ppm and the following
  capacities
• 4000 m3/d (Pilot)
• 16000 m3/d
• 32000 m3/d

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Background RO unit
Feed pressure 60 80 bar (g) Recovery 45 55
Reject 45 Product
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Typical desalination unit block scheme
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Modification of existing SRP unit

• Replacement of NF to RO membranes in the existing
  unit
• Using only 29 bar (g) Low flow and poor salt
  removal

• Increasing the feed pressure (60-80 bar (g))
• Feed pumps, 50P0012A-D, max discharge 30,4 bar
  (g)
• SRP system design pressure, 41 bar (g)
• Feed pumps, membrane packages, vessels and piping
  (BT751) needs to be replaced

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HD case Installation of a RO unit for
desalination

• Pilot installation being evaluated
• Low salinity water rate 4000 m3/d
• 2 wells will be connected to LSW injection

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Issues

• Choice of TDS
• 300 ppm? 1000 ppm?? 3000 ppm??
• HD solution Lowsal / SRP blend
• Feed
• Produced water?/ Sea water? / Sulphate Reduced
  Water?
• HD solution Sea water possibly mixed with small
  amount of SRP water for salinity tuning
• Space
• Weight

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Dimensions Pilot unit (4000 m3/d)
Note 1. Equipment in containers 3 x 40, 1x
20. Note 2. Containers and module steel
construction not included in Vendor A weight
calculations

• Footprint based on module solutions.
• If that is not possible the equipment can be
  placed in other arrangements.

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Challenges

• Predict and estimate reservoir response
• Data acquisition and well monitoring program
• How to verify the EOR effect?
• Evaluate all aspects of well chemistry
• Potential for swelling of clays (injectivity,
  sweep, etc. )

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Possible upsides with Low Salinity Water Injection

• Reducing scale potential
• Scaling influences both well performance and
  separator performance on Heidrun.
• Possible to use other IOR measures which is
  dependant on fresh water supply
• silicate injection for water diversion -
  application needs injection (slug) of low
  salinity water
• Additional experiments are being done on
  core material from the Åre Fm

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Low Sulphate Water
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Design and performance parameters RO unit
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Challenges/obstacle ???

• LoSalTM
• 2 patent applications in Norway regarding Low
  Salinity Water InjectionWO 2005/19007
  tilsvarer norsk søknad nr. 20065924, mens WO
  2006/008439 tilsvarer norsk søknad nr. 20070940.

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Way forward

• Ongoing
• Core flooding experiments Åre to be finalised in
  2Q.
• Tender evaluation and detailed modification study
  for Lowsal Pilot to be finalised in 2Q.
• Final recommendation in July/August
• Pilot decision in September/October
• Platform modifications in September 2009 (RS)
• RO unit installation on HD TLP 4Q 2009
• Start-up late 2009 / early 2010
• Pilot test duration 1-3 years