magnetic resonance imaging logging, development and evolution as a fundamental evaluation tool in...
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Magnetic Resonance Imaging Logging, development and evolution as a fundamental
evaluation tool in the reservoir management
Ron Cherry, Maged Fam and Emiliano López
Geological & Reservoir Overview
Formation Evaluation Problems
High uncertainty in reservoir evaluation using conventional Log
Analysis, due to:
• Multilayer reservoirs made up of an average of 20 stacked layers, about 5 mt. each.
• Low formation water salinity
• Several water/oil and gas/light oil contacts randomly distributed throughout a rock column of 1000 mts. (average 1500 to 2500 mts.)
• Complex lithology (shaly and tuffaceous sand reservoirs)
• Different hydrocarbon types
Core Porosity vs Permeability Core Porosity vs Permeability
Core measurements on samples from
about 60 wells, 800 samples from San
Jorge Basin
Porosity (%)
Perm
eab
ilit
y (
md
)
0.001
0.01
0.1
1
10
100
1000
0 5 10 15 20 25 30 35 40
Porosity (%)
Perm
eab
ilit
y (
md
)
Grain Density Vs Core Porosity
Core Porosity (%)
Gra
in D
en
sit
y (
G/c
3)
Matrix Density Distribution in so called “Sandstone” from San Jorge Basin
Matrix Density Distribution in so called “Sandstone” from San Jorge Basin
MRI Core Porosity (%)
Core
Poro
sit
y (
%)
Core Porosity Vs MRI Core Porosity
MRI Core Porosity vs. Core PorositySan Jorge Basin
MRI Core Porosity vs. Core PorositySan Jorge Basin
Geometric Mean T2 Cutoff vs. DepthGeometric Mean T2 Cutoff vs. Depth
The high degree of variation in the T2 cutoff range may cause some inconsistencies in the final Interpretation.
Thus the SBVI method is a better technique for determining BVI.
Geometric Mean T2 Cutoff (ms)
Dep
th (
m)
Geometric Mean T2 Cutoff Vs. Depth
SBVI Coef.
0.0XXX
Spectral Bulk
Volume Irreductible
SBVI
Spectral Bulk
Volume Irreductible
SBVI
Core Permeability and MRI Permeability Models (md)
Dep
th (
m)
Core Permeability and MRI Permeability Models Vs Depth
N.B.: MRI Permeability data is based on SVBI model
Core Permeability and MRI Permeability ModelsVs Depth
Core Permeability and MRI Permeability ModelsVs Depth
N.B.: MRI Permeability data is based on SVBI model
Core Permeability Vs MRI Permeability ModelsCore Permeability Vs MRI Permeability Models
MRI Permeability Models (md)
Core
Perm
eab
ilit
y (
md
)
MRI Permeability Models Vs Core Permeability
MRIL Pre-job
Planning
ActivationSelection @
Logging speed
MRIL Life CycleMRIL Life Cycle
Specify ObjectivesReservoir Properties &
Problems
Borehole Conditions
Size, mud, temp….etc
Data Processing
&Interpretation
Core Analysisif available
Resistivity log
PrognosisSelection of Zones
to TestSTIMRIL
Compare
Test Results Yes
Met reservoirObjectives
No
Field LogQC
Tool PhysicsTool PhysicsAcquisition Acquisition ParametersParameters
G, TG, TEE, T, TWW
Expected Fm. Fluid Expected Fm. Fluid PropertiesProperties
Temp., Pressure &Temp., Pressure &ViscosityViscosity
Mud PropertiesMud PropertiesBorehole SizeBorehole Size
MRILMRILForwardForward
Modeling Modeling PlannerPlanner
waterwateroiloil
gasgas
waterwateroiloil
gasgas
waterwater
oiloil
MRI Forward ModelMRI Forward Model
Petrophysical Solution!!!
MRI Specific Acquisition and Interpretation Techniques
“one logging pass”
EDMEnhanced Diffusion Method (Hydrocarbons 2-50 cp)
TDATime Domain Analysis (Hydrocarbons < 2 cp)
But….!!!
2400 L/H100 % SW
1800 L/H75 % SW
ShortTE LongTE
MRI Prognosis:Heavy OIL
MRI Prognosis:Water
How can we distinguish Heavy OIL from Water ???
Special Design for Heavy OIL detection…
MRIL Ultra Long TE Activation
ShortTE LongTE UltraLongTE
2400 L/H100 % SW
1800 L/H75 % SW
MRI Prognosis:Heavy OIL
MRI Prognosis:
Water
ShortTE LongTE UltraLongTE
Initial Test Result (8hs Swabbing): 2400 L/H – 100% SW
Final Test Result (24hs Swabbing): 2400 L/H – 88% SW
Heavy OIL Detection Example
Halliburton Question regarding details on test results
Dear Customer:“…If We understand well, the formation was producing water for 8 hours before starting to produce Oil …??You have insisted to keep it producing because there was a very good signal on the MRI Ultra-Long Te activation,….. Is that correct …??...”
Customer’s response
“It's correct...It has been a very good news today, because up to yesterday, we couldn't believe that from that signal it would be only water... We insisted and it was 2400 l/h x 88% of water (may be the amount of water would have declined if we would wait more time... but for us it was enough seeing some oil)…”
Composite Log MRI Interpretation EDM + TDA
Flow920 L/H40 % SW
MRI PrognosisLight Oil w/ HGOR
Shot-Te/Long-Tw TDALong-Te/Long-TW Dif. S.-Te/L.TW-S.Tw
EDM
Fluid Typing: Light OIL
MRI PrognosisLight OIL
Flow x 12mmWet GAS
P/D 280psiP/E 1560 psi
MRI PrognosisGAS
MRI PrognosisGAS
Fluid Typing: GAS
Halliburton’s Reservoir Fluids Prognosis SheetBased on MRIL Interpretation
Magnetic Resonance Imaging (MRI) Logs as a fundamental evaluation tool in the reservoir Management
• Determination of Porosity, Independent to Matrix
• Determination of Bulk Volume Irreducible Water
• Reliable Permeability Indicator (absolute after Calibration)
• Identify Fluid Type (Gas, Oil & Water) by zone
• Identification of Rock Quality…Permeability, Porosity & Clay
• Determine variations of Hydrocarbon types (Resistivity independent)…
…Heavy, Intermediate, Light Oil or Gas
ConclusionsConclusions