how to read a log
TRANSCRIPT
Formation Evaluation
1
PETE 663Formation Evaluationo at o a uat o
Summer Semester 2010
How to Read a Log
Dr. David S. Schechter
Formation Evaluation
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Example Log GRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
10800
10900
Formation Evaluation
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Properties Logs Actually Measure
• Natural radioactivity
• Electron density
• Acoustic travel time
• Hydrocarbon index
• Photoelectric absorption
Formation Evaluation
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Gamma Ray Log
• Measures natural radioactivity of formation – Potassium (K)– Uranium (U)– Thorium (Th)
• Indicates shale presentp
Formation Evaluation
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Example GR LogGRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
GRC1500
10800
GRLog
10900
Formation Evaluation
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Fluorescent Intervals in 1U Sand
• Sharp transition between oil saturated pay and non pay observednon-pay observed by fluorescence in core samples
Formation Evaluation
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Caliper Log GRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700ACAL166
10800
CaliperLog
10900
Formation Evaluation
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Spontaneous Potential (SP)
• Measures the electrical potential in the formation caused by the salinity difference between the drilling mud and the formation water
• SP is generally an indicator of permeability
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
SP LogMV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700SPC
40-160 MV
10800
SPLog
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Example Log With ResistivityILDCMV-160 40
ACAL6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
SNC0.2 200
MLLCF
ILDC0.2 200
108000.2 200
10900
ResistivityLog
Formation Evaluation
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Porosity Logs
• 3 main types
– Bulk density
– Compensated neutron
– Sonic (acoustic)
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Bulk Density LogMV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700RHOC
1.95 2.95
10800
Bulk Density10900
Bulk DensityLog
Formation Evaluation
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Bulk Density Log ExampleGRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
Bulk DensityLog
10800
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
DPHI
DTus/f150 50
001) BONANZA 1
Example Solution Density Log
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
DPHI
10800
10900
Formation Evaluation
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Neutron Log
• Logging tool emits high energy neutrons into formation
• Neutrons collide with nuclei of formation’s atom
• Neutrons lose energy (velocity) with each collisioneach collision
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Porosity From Neutron LogMV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700CNLLC
0.45 -0.15
10800
N t10900
NeutronLog
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Example Compensated Neutron Log
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
NeutronLog
10800
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Example Problem Neutron Log
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
CNLLC
10800
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Example Solution Neutron Log
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
CNLLC
10800
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
Sonic LogMV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700DT
150 50us/f
10800
SonicLog
10900
Formation Evaluation
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Example Sonic LogGRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
SonicLog
10800
10900
Formation Evaluation
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GRC0 150
SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
SPHI
Example Solution Sonic Log MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
ss45 -15
10800
SPHI
10900
Formation Evaluation
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Example Gas EffectGRC
0 150SPC
ILDC0.2 200
SNC
RHOC1.95 2.95
CNLLC
DTus/f150 50
001) BONANZA 1
MV-160 40ACAL
6 16
0.2 200MLLCF
0.2 200
0.45 -0.15
10700
10800
10900
Formation Evaluation
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Fluid DistributionVCLdec0 1
ILDCohmm0.2 200
RHOCNus/f1.65 2.65
CNLLSS
GASus/f1 0
BVW0 VCL
VCL 1
0.6 0
DTCus/f135 55
RHOCN CNLLSS
dec1 0
OIL 1 0
BVWG 1 0
SWdec1 -1
10750
10800