By Riko Mudayana Domain Champion Schlumberger Wireline- Indonesia Production Logging
By Riko Mudayana Domain Champion Schlumberger Wireline- Indonesia
Production Logging
Production Logging
The measurement of fluid
parameters on a zone-by-zone
basis to yield information about
the type and movement of fluids
within and near the wellbore.
Production Logging Applications
Monitor reservoir performance & variations
• New well performance Vs prediction
• Time lapse profile monitoring
• Layered reservoir testing
Evaluate completion performance
• Perforation effectiveness
• Stimulation evaluation
• Formation damage identification
Production Logging Applications Diagnose well problems
• Water entry
• Gas entry
• Leaks and mechanical problems
• Flow behind casing
Other
• Guidance for workover
• Enhanced oil recovery projects
• Identify boundaries for field development
Oil
Water
Basic PL Interpretation
Mono Phase Flow Rate
= Velocity x Area
Multi Phase Flow Rate
= Phase Velocity x Phase Area
Phase Area = Area x Phase Holdup
Vhy Vw
Traditional Interpretation Mixture Velocity
• Spinners
Holdup
• Fluid Density, Capacitance, Local Probes
Phase Velocities
• Correlations
Gradiomanometer Nuclear Capacitance Probe Tools
‘Holdup’ is the area fraction of the pipe occupied by the phase
of interest.
For oil-water flows: yw + yo = 1
For oil-water-gas flows: yw + yo + yg = 1
‘Cut’ is ratio of flowrates. For instance in an oil-water flow,
water cut is given by -
WC (%) = qw/(qo + qw) and more generally by:
WC (%) = qw/qt
‘Superficial velocity’ is the velocity that a phase
would have if it alone flowed in the pipe,
i.e. Q/A.
The sum of the superficial velocities is equal to the mean
velocity: Vsh + Vsl = Vm
Some Definitions
Spinner correction factor
Vaverage = C x Vf
q = C x Vf x A where,
C = velocity profile correction factor,
commonly 0.83. Better, use chart.
A = Area of flow. Use chart to convert
ft/min to flowrate for given casing.
Vf = Fluid velocity from zone calibration line.
Spinner Example 3
6000
6100
6200
6300
6400
Dep
th (
m)
0 5 10 15 20
0 5 10 15 20
Spinner rotation (rps)
Up 110 ft/min
Up 80 ft/min
Up 32 ft/min
Down 115 ft/min
Down 82 ft/min
Down 50 ft/min
A
B
C
D
Crossplot from the Example 3
Down
Sp
inn
er r
ota
tio
n (
rps)
25
20
15
10
5
0
-5
-100 0 100 200
Cable velocity (ft/min)
Up
80 215 320
Holdup Measurement
Holdup Measurement • Main purposes for making a holdup measurements:
– Determine volumetric flow in two and three-phase flow
– Show entry points in two and three-phase flow.
• Holdup measurement tools:
– Gradiomanometer* fluid density tool
– FloView (digital entry fluid imager tool)
– GHOST
– RST TPHL (Three-phase holdup log)
– NFD
– HUM
Two-Phase Flow Computation
Holdup from density
• Mass conservation:
Ao ro + Aw rw = A rlog
yo ro + yw rw = rlog
y is the “holdup”
yw + yo = 1
yw = (rlog - ro) / (rw - ro)
yw = Aw/A
yo = Ao/A
Example
• Oil density: ro = 0.7 g/cc
• Water density: rw = 1.1 g/cc
• Log density: rlog = 0.85 g/cc
• Holdup: yw = (0.85 - 0.7) / (1.1 - 0.7)
yw = 38%
Bubble flow model
Vw Vo Vo= Vw+Vs Vw
Water Oil
A
yw A (1-yw)A
Where Vs is the “slip velocity”
Two-phase Flow Computations
• Qw = Vw Aw Qw = Vw yw A’
• Qo = Vo Ao Qo = Vo yo A’ = (Vw + Vs) (1 - yw) A’
• QT = Qo + Qw
QT = (Vw + Vs) A’ - (Vw + Vs) yw A’ + Vw yw A’
= Vw A’ + (1 - yw) Vs A’
• yw QT = Qw + yw (1 - yw) A’ Vs
Qw = yw QT - yw (1 - yw) A’ Vs
Qo = QT - Qw
Two-phase Flow Computations (ctd)
QT = C Vf A
Qw = yw QT - yw (1 - yw) A’ Vs
Qo = QT - Qw
A’ = 1.39879(D2 - 1.68752)
for ID in inches
Vs in ft/min
Q in bbl/d
Two-Phase Interpretation Exercise
• Well producing both water and oil
• Casing ID: 5”
• Water Density: 1.1 g/cc
• Oil Density: 0.75 g/cc
• 3 up & 3 down passes
Is a friction correction needed?
Well Conditions Two-Phase Interpretation Exercise
6000
6100
6200
6300
6400
Dep
th (
ft)
0 5 10 15 20
0 5 10 15 20
Spinner rotation (rps)
Up 80 ft/min
Up 32 ft/min
Down 115 ft/min
Down 82 ft/min
Down 50 ft/min
A
B
C
D
Density (g/cc))
0.8 0.9 1.0 1.1 1.2
0.8 0.9 1.0 1.1 1.2
Up 110 ft/min
0 2000 4000 6000 8000 10000 6000
6050
6125
6175
6275
6300
6375
6400
Depth (m)
Flow Rate (bpd)
Use of Temperature Measurement
(the original Production Log!)
Temperature log
Spinner Temperature
geothermal gradient
Water Flow behind casing
Uses of pressure
• Well test analysis (kh, skin)
• Reservoir extent, boundaries
• Fluid conversions
• AOF, SIP determination
Advance Production Logging
†Real-time logging only
FloView
GHOST
Water Entry Detected
in High-Rate Gas Well
• Over 14 MMcf/D gas downhole
production
• Less than 120 BWPD water
downhole production
• Character of bubble count curves
indicates water recirculation in
wellbore
• Water entry at X270 seen by
Bubble counts
First oil entry
Water entry
First Oil Entry Detection
PS Platform Application Sensors
QUESTION ?