Produced Water Reinjection Performance Joint Industry Project

1
Produced Water Reinjection PerformanceJoint
Industry Project

• TerraTek, Inc.
• Triangle Engineering
• Taurus Reservoir Solutions (DES)
• E-first Technologies
• Advantek

2
Data analysis

• Data sets analyzed previously
• Elf 3 Well 1 2, Statoil Heidrun, Marathon W.
  Brae
• Additional data sets
• Phillips T field
• KMG G field
• Simple damage model applied to Elf 3
• Each dataset has unique interpretation problems
• Analysis of impairment of injectivity (k, S)

3
Methodology for analysis

• Convert THP to BHP
• Find and mark all significant events
  (stimulations, transition matrix-frac,)
• Conventional p,Q vs t and p vs Q plots
• Modified Hall plot (consider variations in pres)
• Check initial (or expected) injectivity by
  analytical or numerical calculation

4
Methodology for analysis contd

• If fracturing identified, check frac pressure
  from all available sources
• Calculate II in matrix mode
• Calculate II in fracture mode
• If good data is obtained for number of datasets,
  correlate II changes with basic parameters
• Try to develop general correlation (similar to
  PEA23)

5
Phillips T field characteristics

• Fractured chalk reservoir, production wells have
  negative skins
• Raw data processed through the BHP spreadsheet
  tool - validation
• Reservoir pressure increased with time from 2125
  to 3000 psia (92-96). Pres vs t for analysis was
  taken from reservoir simulator output
• SW injection only (additional info -acid washes)

6
Phillips T field chalk Well 1
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Phillips T field Well 1 reservoir pressure
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Phillips T field chalk Well 2
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Phillips T field Well 2 reservoir pressure
10
KMG G field

• 3-10 D, 32 porosity, 2 wells (W4 and W4A)
• Mixture of PW and aquifer water from the start
• OH gravelpack (W4) or excluder (W4A)
• No fracturing? (no data on frac gradient either)
• Almost exact analog to Harding (SPE .UK DOE)
• Assumed high completion skin
• S100 for gravelpack (W4)
• S250 for excluder screen (W4A)

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KMG G field well W4
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KMG G field W4 injectivity decline
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KMG G field well W4A
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KMG G field well W4A injectivity decline
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KMG G field injectivity comparison with BP
field D
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Summary
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Conclusions

• All data sets show significant reduction of
  injectivity compared to theoretical
• Perm reduction and skin plots help visualize the
  problem
• Completion skin included as a separate item now
• Each case must be processed very carefully,
  assembly line approach will give misleading
  results
• Simple damage model looks promising, can
  incorporate dynamic changes (p(t), stimulations,
  )