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Society of Petroleum Engineers
How to maximize the value of mature HC fields?
Workshop
Budapest, 18. November 2010.
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Getting the Most out of PNC & PNS LogsTo Increase Production in Mature Fields
Jason Gendur and Frank Thompson
Schlumberger
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Diagnose Existing Problems inProducing Wells
Find Bypassed Hydrocarbons
Remedial Actions
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Getting the Most out of PNC & PNS LogsTo Increase Production in Mature Fields
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Petrophysical Evaluation
Problems
Completions Restrictions (Tool OD)
Behind-Casing Measurements
Flowing or Shut in
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Tubing Scale or Corrosion Casing Condition Completions Design
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PNS Vs PNC
Pulsed Neutron Capture
GR Count Vs time
Measuring macroscopic neutron
cross section (S)
Pulsed Neutron Spectroscopy
GR Count Vs Energy For C/O Ratio
Spectroscopy
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PNC
PNS
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Applications in Mature Fields
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Problem Conditions Solutionwater saturation in depletedoil reservoir
Salty connate water PNC logging
water saturation in depletedoil reservoir
Fresh water PNS logging
Bypassed gas zone detection Thin layers PNC logging with WINR gasdetection
Petrophysical evaluation inold field
Only resistivity-SP open holelogs available
PNS & PNCSpectrolith for lithology
Oil saturation Gas cap PNS and PNC
Current oil saturation Water injection, variable
water salinity
PNS and PNC
Water production Flow behind casing Water flow logging
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PNC and PNS Diagnostics
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RST Pro
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PNC Measurement
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Sigma (S)
Porosity
BoreholeSalinity
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Sigma Log
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Sigma Log
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GRCorrelation Shale
Volume
Neutron Porosity
Sigma
Gas IndicationCount Rates
IRAT
WINR
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GRCorrelation Shale
Volume
Neutron Porosity
Sigma
Gas IndicationCount Rates
IRAT
WINR
log = (water * fSw) Water+ (hydrocarb* f(1-Sw)) Hydrocarbon+ (matrix * (1-f-Vshale)) Matrix+ (shale * Vshale) Shale
Problem Conditions SolutionBypassed gas zonedetection
Thin layers PNC logging with WINRgas detection
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Sigma Log
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hywamaclmahyma Vcl
Sw
SS
SSSSSS
f
flog
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WINR Curve for Gas
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PNC Measurement
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PNS Measurement C/O
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PNS Measurement C/O
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PNS Measurement Spectrolith
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PNS Spectrolith
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SONIC
TRAVEL TIMESDEEP
MEDIUM
SHALLOW
GAMMA RAY
Are highresistivityintervals pay?
Problem Conditions SolutionPetrophysical evaluation inold field
Only resistivity-SP openhole logs available
Spectrolith for lithologydetermination
SONIC
TRAVEL TIMESDEEP
MEDIUM
SHALLOW
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SONIC
TRAVEL TIMESDEEP
MEDIUM
SHALLOW
GAMMA RAY
Are highresistivityintervals pay?
PayZone?
Problem Conditions SolutionPetrophysical evaluation inold field
Only resistivity-SP openhole logs available
Spectrolith for lithologydetermination
SONIC
TRAVEL TIMESDEEP
MEDIUM
SHALLOW
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SONIC
TRAVEL TIMESDEEP
MEDIUM
SHALLOW
GAMMA RAY
Are highresistivityintervals pay?
NO
Payzone in sand?YES
Problem Conditions SolutionPetrophysical evaluation inold field
Only resistivity-SP openhole logs available
Spectrolith for lithologydetermination
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Lithology
Gas Sigma
Oil Sigma & C/O
Problem Conditions SolutionOil saturation Gas cap PNS and PNC
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Problem Conditions Solution
Petrophysical evaluation inold field
Only resistivity-SP openhole logs available
Spectrolith for lithologydetermination
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Old Logs
Unswept Oil
DepletedLayer
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Water injection: Fingering of injectedwater drops initialproduction (300b/d) Variable watersalinity C/O mode
OHRST
Problem Conditions SolutionCurrent oil saturation Water injection, variable
water salinityPNC logging
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Conclusion
PNS and PNC measurements from RSTPro (Sigma, C/O,Spectrolith) are used to maximize the value of mature fields
Diagnose existing problems
Water saturation in depleted oil reservoirs
Identify fluid contacts (water-oil-gas)
Find bypassed hydrocarbons
Gas detection in thin zones
Remaining oil saturation
Remedial actions
Water production behind casing
Quantitative petrophysical evaluation in old wells
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Questions
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