Upload
others
View
37
Download
5
Embed Size (px)
Citation preview
Downhole Production Logging Tools
Production Logging Fundamentals
Learning Objectives
By the end of this lesson, you will be able to:
Demonstrate the principles and operation of the logging toolsassociated with flowmeter tools
Demonstrate the principles and operation of the basic temperaturelogs
Demonstrate the principles and operation of basic radioactivetracer logs
Discuss the added value of running a downhole video log inaddition to production logs
Present the principles and operation of basic spinner flowmeterlogs
Present the principles and operation of the gradiomanometer log
Illustrate the performance of cased hole logs in single phase flow
Understand the interest of running multiple tools within aProduction Combination Tool
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
1
Major Through-Tubing Cased Hole Production Tools
Casing Collar Locator Log Gamma Ray Log Caliper Noise Logs Temperature Logs Radioactive Tracer Logs Spinner Flowmeter Logs Pressure Logging Tool Gradiomanometer Logs
Not Covered
This Section
Pulsed Neutron (TDT) Logs
Permission to publish by the Society of Petroleum Engineers of AIME.Copyright 1983 SPE-AIME.
Counting Pipe Collars is a Common Application
Casing Collar Locator (CCL)
Counting Pipe Collars is a fundamental need for depth correlation
Co
llar
loca
tor
Su
b. 2
ft (.
61
m)
Bottom magnet
Top magnet
High impedance amplifier & voltmeterCOPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
2_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Permission to publish by the Society of Petroleum Engineers of AIME.Copyright 1983 SPE-AIME.
Counting Pipe Collars is a Common Application
Casing Collar Locator (CCL)
Counting Pipe Collars is a fundamental need for depth correlation
Co
llar
loca
tor
Su
b. 2
ft (.
61
m)
Bottom magnet
Top magnet
High impedance amplifier & voltmeter
Initially correlated in depth by using a specific open hole log (usually the Neutron-Density or Gamma Ray log)
Subsequent cased hole runs can be correlated by using only the CCL
The CCL is a short tool that is run immediately below the cable head
Requires an electrical feed through to communicate with thesensors of the remaining tools
9000'
9100'6'
9050'
Depth
(2743 m)
(2758 m)
(2774 m)(1.8 m)
A BCollar Logs
Remember: Different reading due to cable stretch
Typical Casing Collar Recorder – CCL Log
Permission to publish by the Society of Petroleum Engineers of AIME.Copyright 1983 SPE-AIME.
A. Running in hole
B. Pulling out of hole
Limitations
Robust and rugged instrument.
1. Flush joint casing joints may bedifficult to detect.
2. Some non-magnetic CorrosionResistant Alloy (CRA) materials willnot provide collar indications.
3. Some pipe manufacturers provide veryconsistent pipe lengths, and thus novariation in casing pipe joint length.
4. Small diameter CCL’s (centralized)may not detect collars in largediameter casing strings.
Advantages
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
3
Gamma Ray (GR) Tool
Generally use a scintillator crystal and photomultiplier receiver for maximum log quality
Log reflects the shale content of rocks, as radioactive elements tend to concentrate in clays and shales
“Clean” formations usually have low radioactivity
At least one GR tool will be run during the open hole logging program
• Subsequent cased hole GR logs can be correlated to this log
The GR sonde detector measures gamma radiation
Gamma Ray: correlation with open hole logs• Continuously measures and records natural radioactivity in the
formations adjacent to the wellbore using radioactive decay of:– Potassium, uranium, and thorium elements
Gamma Ray (GR) Tool
Drill Collar
Gamma Ray Detectors
Dual Detectors
Bank A Bank B
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
4_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Gamma Ray: correlation with open hole logs• Continuously measures and records natural radioactivity in the
formations adjacent to the wellbore using radioactive decay of:– Potassium, uranium, and thorium elements
Gamma Ray (GR) Tool
Drill Collar
Gamma Ray Detectors
Dual Detectors
Bank A Bank B
Generally use a scintillator crystal and photomultiplier receiver for maximum log quality
Log reflects the shale content of rocks, as radioactive elements tend to concentrate in clays and shales
“Clean” formations usually have low radioactivity
At least one GR tool will be run during the open hole logging program
• Subsequent cased hole GR logs can be correlated to this log
The GR sonde detector measures gamma radiation
Main applications• Depth control for cased hole wireline operations• Precision depth correlation
– When radioactive sources have been introduced at a particular casing depth or by perforating charge
• Sometimes a Gun-GR tool is used with perforating guns
Advantages• Simple tool requiring minimal interpretation
Limitations• GR definition or variation may be low over intervals of interest,
making correlation difficult– Can be the result of poor natural variations of gamma ray strength
– Signal suppression due to sensing multiple through strings– Centralized small diameter tool inside a large casing
Monitors wellbore condition (open or cased hole)
After a drilling phase, caliper data are integrated to determine the volume of the open hole
Caliper offers a qualitative indication of the condition of the wellbore and the degree to which the mud system has maintained hole stability
Very useful with any Production Logging run
The caliper measurement point corresponds exactly to the measurement point of the flowmeter impeller
Caliper
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
5
Blades Monitors wellbore condition (open or cased hole)
After a drilling phase, caliper data are integrated to determine the volume of the open hole
Caliper offers a qualitative indication of the condition of the wellbore and the degree to which the mud system has maintained hole stability
Very useful with any Production Logging run
The caliper measurement point corresponds exactly to the measurement point of the flowmeter impeller
Caliper
A B
Moving caliper
arm
or multi-finger types
Caliper tool: Variable resistance
Caliper arm
Variable resistor
Main Applications Limitations
1. Correct the flowmeter readings for diameter variations due to either heavily scaled tubulars or differences in open hole completions
2. Locate packer seats in open hole sections
3. Determine restrictions for future tubing or casing work (workover planning)
4. The caliper data can be used independently for determining general internal corrosion, paraffin buildup, or mineral scaling
• Normal two or four arm calipers will only give general indications of corrosion and other more sophisticated tools need to be run to examine the corrosion issues further
Blades
Caliper
A B
Moving caliper
arm
or multi-finger types
Caliper tool: Variable resistance
Caliper arm
Variable resistor
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
6_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Blades Monitors wellbore condition (open or cased hole)
After a drilling phase, caliper data are integrated to determine the volume of the open hole
Caliper offers a qualitative indication of the condition of the wellbore and the degree to which the mud system has maintained hole stability
Very useful with any Production Logging run
The caliper measurement point corresponds exactly to the measurement point of the flowmeter impeller
Caliper
A B
Moving caliper
arm
or multi-finger types
Caliper tool: Variable resistance
Caliper arm
Variable resistor
Main Applications Limitations
1. Correct the flowmeter readings for diameter variations due to either heavily scaled tubulars or differences in open hole completions
2. Locate packer seats in open hole sections
3. Determine restrictions for future tubing or casing work (workover planning)
4. The caliper data can be used independently for determining general internal corrosion, paraffin buildup, or mineral scaling
• Normal two or four arm calipers will only give general indications of corrosion and other more sophisticated tools need to be run to examine the corrosion issues further
Multi-finger Calipers• Motorized Centralizers to ensure effective centering force
– Equipped with rollers to prevent casing and tubing damage
For cased hole logging, the caliper will give indications about: • Conditions inside the casing• Damage• Scale• Paraffin deposits
• Hydrodynamic characterization of reservoirs
• Identification of production and injection intervals
Noise Log
• Well integrity analysis
Spectral Noise Logging (SNL) is an acoustic noise-measuring technique used in oil and gas wells for:COPYRIG
HT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
7
Noise Log
Spectral Noise Logging (SNL) • Records acoustic noise generated by fluid or gas flow • Tool listens passively to downhole noise such as gas bubbling up
through liquid in the wellbore– Behind pipe, a channeling flow passes through “tight spots”, which
cause higher velocities, sudden pressure reductions and significant flow turbulence
– The noise-logging tool listens for noise associated with the turbulence
• The tool includes piezoelectric crystal transducers which convert the oscillating pressure of wellbore sound to corresponding oscillating voltage
– The oscillating voltage is applied to a speaker at the surface, as well as each of four high-pass filters
• Each high-pass filter detects nothing below its filter range• Log noise filters for 200, 600, 1000 & 2000 Hz• Two-phase flow occurs at about 200 to 600 Hz• High rate single phase flow occurs above 1000 Hz• Sound is highly attenuated by gas• Tool works best for low rate gas leaks
Noise Spectrum
200
600
1,000
2,000
Differential Pressure
Single phase
Two phase
Rel
ativ
e am
plit
ud
e
Frequency, hz
Rel
ativ
e am
plit
ud
e
Frequency, hz
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
8_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Noise Spectrum
200
600
1,000
2,000
Differential Pressure
Single phase
Two phase
Rel
ativ
e am
plit
ud
e
Frequency, hz
Rel
ativ
e am
plit
ud
e
Frequency, hz
High noise amplitudes indicate locations where the flow path is submitted to turbulence
The noise log has been used as an indicator of channeling behind pipe
• Flow through channel is indicated on a noise log by the presence of high amplitude noise at places where restrictions in the channel causes throttling of fluid
Flow through a leak results in a pressure drop that generates detectable noise
Noise Log Principle
Piezoelectric Crystal
Microphone
2000
1000
600
200 HZ
5.7
14.1
27.3
55.0
Millivolts
High PassFiltersCOPYRIG
HT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
9
Noise Log Principle
Piezoelectric Crystal
Microphone
2000
1000
600
200 HZ
5.7
14.1
27.3
55.0
Millivolts
High PassFilters
Filter’s output consists of positive excursions from neutral alternating with negative excursions
Amplitude is measured two ways1. Measure from peak of positive excursions to trough of following
negative excursion– “Peak to peak” amplitude
– “Standard gain” or “Standard sensitivity” recording
2. Measure from the peak of a positive excursion to neutral– “Peak” amplitude
– “One-half standard gain” recording
Noise Log Principle
Piezoelectric Crystal
Microphone
2000
1000
600
200 HZ
5.7
14.1
27.3
55.0
Millivolts
High PassFilters
Filter’s output consists of positive excursions from neutral alternating with negative excursions
Amplitude is measured two ways1. Measure from peak of positive excursions to trough of following
negative excursion– “Peak to peak” amplitude
– “Standard gain” or “Standard sensitivity” recording
2. Measure from the peak of a positive excursion to neutral– “Peak” amplitude
– “One-half standard gain” recording
Measurements• A single station measurement lasts 3 to 4 minutes• Relocating the tool requires 1 minute• Thus, the logging rate is approximately 15 stations per hour, and
a 4-hour logging run accommodates 60 measurements• 30 measurements are used for a course-measurement grid, with
successive measurements separated by 1/30th of the total survey interval
• The remaining 30 measurements are used for detailing areas of interest
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
10_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Noise Log Interpretation
Single Phase Leak Gas into Liquid Leak
A – Noise Level PeakMillivolts
B – Noise Level Peak to PeakMillivolts
DE
PT
H
Noise Log Interpretation
Single Phase Leak Gas into Liquid Leak
A – Noise Level PeakMillivolts
B – Noise Level Peak to PeakMillivolts
DE
PT
H1. Sound reflects downward at interface2. The tool sensor is built for coupling
to liquid rather than gasCOPYRIG
HT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
11
A well was drilled through two gas zones
• Plugged and abandoned, and the wellhead cut at the sea floor
Six months later• An internal gas blowout reached
the mudline, causing the sea to churn
• A relief well was drilled to kill the uncontrolled zone
A well was drilled through two gas zones• Plugged and abandoned, and the wellhead cut at the sea floor
Six months later• An internal gas blowout reached the mudline, causing the sea to
churn• A relief well was drilled to kill the uncontrolled zone
(762)
(1067)
(1372)
(914)
(1219)
(762)
(1067)
(1219)
(1372)
(914)
Noise Log Application: Internal Well Blowout
Temperature Log
Temperature log• Simplest, most accurate, and most widely applicable production log
Temperature gradient changes are caused by natural phenomena within the earth’s crust, and fluid movement
Two curves:• Gradient curve – temperature vs depth• Differential curve – derivative of temperature with depth
Temperature logs will be run both with the well flowing and shut in
Gas expansion cooling is about 1°F (0.5oC) / 40 psi (276 kPa)
High water flow heating is about 3°F (1.5oC) / 1000 psi (6895 kPa)
Qualitative data help derive “where”, not “how much”
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
12_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
HRT = High Resolution TemperatureHRT = High Resolution Temperature
Temperature Log
CCL
Electronic cartridge
Bridge
Temperature-sensitive resistor
Geothermal Gradient Variation
Temperature in well depends on factors such as:
• Temperature of surrounding formations
• Wellbore flow conditions• Heat transfer characteristics
of completion• Fluid movement near the
wellbore
The temperature distribution in the earth’s crust is called the Geothermal Temperature Profile
• The temperature trend in the earth’s crust increases with depth, leading to a geothermal temperature profileGeothermal Gradient Varies Due to Rock
Properties Through Layers
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
13
Local Geothermal Gradient
In desert conditions, surface temperature may initially decrease, reach a neutral point, and then increase
The geothermal temperature profile varies significantly from area to area, and the slope of the geothermal temperature varies from formation to formation
COOKING LAKE
Example of Geothermal Gradient
Knowledge of the geothermal temperature profile is necessary for temperature log interpretation
• Record one baseline log within a well shut-in and stabilized, before production start-up
The geothermal gradient is generally assumed to be constant when interpreting temperature logs in a given area
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
14_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Temperature Log Applications
Detect changes in surrounding temperature
Identify annulus cement top after cement hydration
Detect cooling effects of expanding gas (Joule-Thomson effect)
Confirm operation of gas lift valves
Help evaluate fracture treatments
Identify true reservoir temperature for other studies, such as PVT
Identify flow behind pipe (qualitative indication only)
Identify leaks in completion (packer, tubing, etc)
Qualitative evaluation of fluid flow by comparing with geothermal and/or shut in gradients
Limitations: Quantitative interval flow rates cannot be determined
Time lapse techniques during successive shut-in passes effective for identifying relative volume of produced/injected fluids
Temperature Log
Temperature profiles can be used to indicate where fluids are entering the wellbore
Geothermal gradient
Flow without gas entry
Flow with gas entry
Asymptote
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
15
Geothermal gradient logged after cementing a casing
string to identify cement top while cement is curing
(Exothermic setting reaction)
Logged Temperature Gradient
TEMPERATURE
INCREASE
CEMENT TOP
Logged Temperature Gradient
Logged Geothermal Gradient to Identify Lost Circulation
If an initial (base line) temperature log has been recorded (Run #1),
Then, after a small fluid volume has been pumped into the well,
Run #2 shows a gradient shift occurring above the lost circulation zone providing evidence of a leak from an old or corroded casing.
Temperature
Increase
Lost circulation zonee.g., leak in old casing
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
16_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
(3200)
(3505)
(3658)
(3810)
(3962)
(4115)
(4267)
(4328)
(24.5 cm)
Temperature Log Example
Hot fluid flow behind casing from source hereApparently, cross flow to about 11,000 ft (3353 m)
Initial Temperature Log
• Log illustrates estimated normal thermal gradient and increased sustained temperature (fluid flow upwards outside pipe)
• Interpretation: high temperature fluid flow behind casing from 13,850 ft (4,221 m)
Before & After Remedial Work
Before Remedial WorkoverAfter Remedial Workover
Temperature Logs
Temperature and Noise Logs
Before After
Noise Logs
(3200)
(3505)
(3658)
(3810)
(3962)
(4115)
(4267)
(4328)
(24.5 cm)(3505)
(3383)
(3414)
(3444)
(3475)
(3536)
(3566)
(3597)
(3627)
(3658)
(3688)
(3719)
(3749)
(3780)
(3810)
(24.5 cm)
(19.4 cm)
(24.5 cm)
(3505)
(3383)
(3414)
(3444)
(3475)
(3536)
(3566)
(3597)
(3627)
(3658)
(3688)
(3719)
(3749)
(3780)
(3810)
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
17
TemperatureD
epth
GeothermalGradient
Injection
Injection Zone
Shut-in
Typical Water Injection Well
Water Injection Well – Temperature Log
This log illustrates • The water injection
temperature profile
And,• The shut-in (1 hr)
temperature profile as the warmer formation increases the temperature of the shut-in column of injected cold water
This log also indicates a possibility of channeling below the depth of the lowest perforations
(1524)
(1509)
(1522)
(1514)
(1530)
(1555)
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
18_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Friction
within rocks
Gas expansion
Channeling
Example of Thermal Anomaly
Gas
Gas or liquid?
Well Temperature Log
Production zones may or may not be clearly identified on a temperature log
When free gas is flowing from the reservoir, pressure drawdown will induce a significant cooling of the gas in the near-wellbore vicinity due to Joule-Thomson effect
• Gas entry locations are identified by cool anomalies on a temperature log
A
B
C GgradDTSProd-1RateRateCumRateCOPYRIG
HT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
19
Temperature Gradient Flowrate Interpretation
Entry 1Q1
Entry 2Q2
Entry 3Q3
TL3
TL1
(Q1 + Q2 ) TL2 = Q1 T2 + Q2 TG2
Qi = Qi-1 (Ti - TLi) / (TLi - TGi)
TG2
TG3
T2TL2
T3
For more information, review the Romero-Juarez Method
which uses a similar gradient method
Temperature Gradient Flowrate Interpretation
Entry 1Q1
Entry 2Q2
Entry 3Q3
TL3
TL1
(Q1 + Q2 ) TL2 = Q1 T2 + Q2 TG2
Qi = Qi-1 (Ti - TLi) / (TLi - TGi)
TG2
TG3
T2TL2
T3
Qi = the flowrate from entry #i
TGi = the static geothermal temperature at depth of entry #i
TLi = the flowing fluid temperature at top of entry #i
For more information, review the Romero-Juarez Method
which uses a similar gradient method
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
20_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Temperature Logging Recommendations
Record a full (top to bottom) reliable geothermal gradient log (base line log) during the first Production Logging run
Routine: stabilize rate for 48 hours, log, shut in for about 24 hours
Record temperature profiles, well shut-in, at repeated time intervals
Log down and up, make re-runs (after 1-2 hrs), check log response
Analyze temperature log versus flowmeter log
Temperature profiles can be used for flow rate estimation
Document results and recommendations
Remember: in high rate gas wells, with low compressibility, the Joule-Thomson effect may be reversed and create a local heating at the fluid entry point (molecular friction effect)
Radioactive Tracer Logs
Use peak-to-peak transit time
Require precise well diagram
Techniques: controlled time and interval
Typically use iodine I-131 (8 day half-life)
Investigates only about 1 ft (0.31 m) deep outside casing
Good for relatively low injection rates
Mostly used on water injection wells
Accurate logging of sequence of events essential
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
21
Radioactive Tracer Tool
Shot = 20 cc
CCL
Ejector Port
Top Gamma Detector
Bottom Gamma Detector
Radioactive Tracer Log: Tracer Loss Method
Timed Logging Runs to Detect Radioactive Fluid Location
Tracer Loss Measurement• Peak = slug position
• Signal amplitude proportional to flowrate
D
C
B
A
Run No. 14 min
Run No. 26 min
Run No. 38 min
Run No. 410 min
Run No. 512 min
Run No. 614 min
Run No. 716 min
Run No. 818 min
Run No. 920 min
(1494)
(1524)
(1518)
(1512)
(1506)
(1500)COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
22_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Radioactive Tracer Log: Velocity Shot
Recorder on time drive detector stopped @ 4900' (1494 m)
Ejector @ 4895' (1492 m)
Start Time
Reaction time in casing “A” = 10 sec
Material clears tool in 33 sec
Material channeling to 4900' (1494 m)outside casing
Material being
flushed
into formation
(1494)
(1524)
(1518)
(1512)
(1506)
(1500)
(1497)
(1503)
(1509)
(1515)
(1521)
Radioactive Tracer Guidelines
Caliper any open hole and run base log
Log above injection zone, check flow rate
Use two gamma ray detectors and centralize tool string
Space to get reasonable tool detection times (> 10 sec)
Use controlled times to find injection zones
Use controlled interval to find flow rates
Investigate all identified anomalies
Document results
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
23
Continuous Flowmeter (CFM) Principle
The spinner flowmeter is the most commonly used device for measuring flow profiles, both in injection and production wells.
Impeller placed in well to measure fluid velocity
• Signal period on output coil • Frequency of rotation F• Measures in rps
Characteristics• rps are filtered before recording• Spin direction is now presented on logs
Continuous Flowmeter Sonde (CFS)• Maximum Pressure (psi) 15000 (103 mPa)
• Maximum Temperature (°F) 350 (177 °C)
• Makeup Length (inches) 24.0 (61 cm)
Lower Bearing
Spinner
Pickup Coil
Upper Bearing
Electrical Connection Flowmeters must be centralized in the
wellbore so that accurate flow velocity of flow stream center can be determined
Use a caliper for accurate flow determination
To determine the minimum fluid velocity required for spinner to rotate:
1. Multiple up and down passes are made and calibration chart is developed to determine fluid flow velocity and cable logging speed
2. Spinner velocity will be at fluid conditions at the point of measurement and will need to be converted back to stock tank conditions during final calculations
Magnet
Temperature and Flowmeter Logs – Example 1
Increased flow
Dep
th
Temperature
Dep
th
Temperature Log Continuous Flowmeter
G
TM
A’
A
T’
T
P
1° C.
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
24_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
M2
Temperature and Flowmeter Logs – Example 2
M1
T2
A2
A2T
T1P1
P2
Temperature Increased Flow
Temperature Log Continuous Flowmeter
Dep
th
Dep
th
Anomaly
Temperature and Flowmeter Logs – Example 3
Formation Producing Liquid at MLiquid Entering Casing at M
Formation Producing Liquid at MLiquid Entering Casing Through
Perfs at M’
M M
M’
Flow Behind PipeCOPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
25
Temperature and Flowmeter Logs – Example 4
Anomaly
Gas Expansion / Prod Rate at MLow Perm Rock Demonstrates More Cooling due to
Greater Pressure Drop at Formation / Borehole interface
M
Expanding from Formation into Formation / Casing at MGas Flowing from M with Little or No Expansion
Gas Expanding from Annulus into Casingthrough Perforations at M’
M
M’
Spinner Flowmeter Tools
Types: continuous, full bore, diverter
Calibration in hole required
Two-pass technique applied (log up and down)
Use together with gradiomanometer (density differences)
Slippage velocity and water holdup applied for calculation of two-phase flow rates Qoil and Qwater
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
26_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Full Bore Flowmeter Sonde (FBS)
Early flowmeters were designed for low flowrates and adapted accordingly
• However, mechanical design involved flaws that sometimes induced operational complications
• These weaknesses led to the development of the Full Bore Flowmeter (FBS) tool
Maximum Pressure (psi) 20000 (138 mPa)
Maximum Temperature (F) 392 (200 °C)
Weight (lbs) 11 (5 kg)
Makeup Length (inches) 35.1 (89.2 cm)
Courtesy of Schlumberger
Full Bore Flowmeter Sonde (FBS)
Early flowmeters were designed for low flowrates and adapted accordingly
• However, mechanical design involved flaws that sometimes induced operational complications
• These weaknesses led to the development of the Full Bore Flowmeter (FBS) tool
Maximum Pressure (psi) 20000 (138 mPa)
Maximum Temperature (F) 392 (200 °C)
Weight (lbs) 11 (5 kg)
Makeup Length (inches) 35.1 (89.2 cm)
Courtesy of Schlumberger
Uses collapsible large spinner blades that unfold only when exiting the tubing
Run in collapsed position within centralizer arms while within the tubing
Centralizer arms protect spinner blades
• However, both are easily damaged
• Both expand to large fraction of casing inner diameter by unfolding when reaching the larger casing
Size of spinner blades allows largerflow cross section to be monitored
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
27
Full Bore Flowmeter Sonde (FBS)
Early flowmeters were designed for low flowrates and adapted accordingly
• However, mechanical design involved flaws that sometimes induced operational complications
• These weaknesses led to the development of the Full Bore Flowmeter (FBS) tool
Maximum Pressure (psi) 20000 (138 mPa)
Maximum Temperature (F) 392 (200 °C)
Weight (lbs) 11 (5 kg)
Makeup Length (inches) 35.1 (89.2 cm)
Courtesy of Schlumberger
Uses collapsible large spinner blades that unfold only when exiting the tubing
Run in collapsed position within centralizer arms while within the tubing
Centralizer arms protect spinner blades
• However, both are easily damaged
• Both expand to large fraction of casing inner diameter by unfolding when reaching the larger casing
Size of spinner blades allows largerflow cross section to be monitored
The FBS tool is more complex than the
continuous flowmeter but tends to provide more
reliable flow data as the spinner blades cover a
larger fraction of the wholeflow path.
Diverter Flowmeters
Diverter/Basket Flowmeter
Basket Size Small Large
Minimum Casing, in (cm) 4 ½ (11.4) 7 (17.8)
Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5)
Maximum Flow, bbl/d (m3/d) 1800 (286.2) 1000 (159)
Maximum Pressure (psi) 15000 (103 mPa)
Maximum Temperature (F) 350 (177 C)
Weight (lbs) Makeup Length (in) 60 (152 cm)
Maximum Flow (bbl/d)• Basket Open 2000 (318 m3/d)• Basket Closed 10000 (1589.9 m3/d)
Maximum Deviation () 60
Single phase (bbl/d) >100 (15.9 m3/d)
Qo in two phases (bbl/d) > 30 (4.8 m3/d)
Qw in two phases (bbl/d) >400 (63.6 m3/d)
Accuracy (%) 10
Exit Ports
Spinner
Hold-up Meter
Water Resistivity
Cell
DC Motor
The most accurate of the spinner devices when low total rates and multiphase flow occurs.
• Can detect flowrates as low as 10 to 15 bbl/d (1.6 to 2.4 m3/d).
– A typical 1-11/16-in (4.3 cm) tool has a barrel ID of approximately 1.45 in (3.9 cm).
– A flow of 10 bbl/d results in a velocity of 3.4 ft/min (1.04 m/min) inside the barrel.
– Because of the limited clearance between the spinner and the barrel, this velocity is enough to overcome friction and rotate the spinner.
– A flow of 100 B/D passes through the barrel at 34 ft/min (10.4 m/min) – enough to start the homogenization of the flow.
– In a casing, a rate of 2,000 bbl/d (318 m3/d)is needed to obtain the same effect around a continuous spinner.
– The tool can be calibrated directly for such flow.
Metal PetalsCOPYRIG
HT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
28_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Diverter Flowmeters
Diverter/Basket Flowmeter
Basket Size Small Large
Minimum Casing, in (cm) 4 ½ (11.4) 7 (17.8)
Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5)
Maximum Flow, bbl/d (m3/d) 1800 (286.2) 1000 (159)
Maximum Pressure (psi) 15000 (103 mPa)
Maximum Temperature (F) 350 (177 C)
Weight (lbs) Makeup Length (in) 60 (152 cm)
Maximum Flow (bbl/d)• Basket Open 2000 (318 m3/d)• Basket Closed 10000 (1589.9 m3/d)
Maximum Deviation () 60
Single phase (bbl/d) >100 (15.9 m3/d)
Qo in two phases (bbl/d) > 30 (4.8 m3/d)
Qw in two phases (bbl/d) >400 (63.6 m3/d)
Accuracy (%) 10
Exit Ports
Spinner
Hold-up Meter
Water Resistivity
Cell
DC Motor
Metal Petals
Diverter Flowmeters
Diverter/Basket Flowmeter
Basket Size Small Large
Minimum Casing, in (cm) 4 ½ (11.4) 7 (17.8)
Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5)
Maximum Flow, bbl/d (m3/d) 1800 (286.2) 1000 (159)
Maximum Pressure (psi) 15000 (103 mPa)
Maximum Temperature (F) 350 (177 C)
Weight (lbs) Makeup Length (in) 60 (152 cm)
Maximum Flow (bbl/d)• Basket Open 2000 (318 m3/d)• Basket Closed 10000 (1589.9 m3/d)
Maximum Deviation () 60
Single phase (bbl/d) >100 (15.9 m3/d)
Qo in two phases (bbl/d) > 30 (4.8 m3/d)
Qw in two phases (bbl/d) >400 (63.6 m3/d)
Accuracy (%) 10
Exit Ports
Spinner
Hold-up Meter
Water Resistivity
Cell
DC Motor
The most accurate of the spinner devices when low total rates and multiphase flow occurs.
• Can detect flowrates as low as 10 to 15 bbl/d (1.6 to 2.4 m3/d).
– A typical 1-11/16-in (4.3 cm) tool has a barrel ID of approximately 1.45 in (3.9 cm).
– A flow of 10 bbl/d results in a velocity of 3.4 ft/min (1.04 m/min) inside the barrel.
– Because of the limited clearance between the spinner and the barrel, this velocity is enough to overcome friction and rotate the spinner.
– A flow of 100 B/D passes through the barrel at 34 ft/min (10.4 m/min) – enough to start the homogenization of the flow.
– In a casing, a rate of 2,000 bbl/d (318 m3/d)is needed to obtain the same effect around a continuous spinner.
– The tool can be calibrated directly for such flow.
Metal Petals
Small clearance between the spinner and the ID of the barrel assures almost no diversion of flow around the spinner.
As the spinner rotates, it generates a specific number of voltage pulses per revolution.
• The pulse rate from the tool can be transmitted through the logging cable for surface recording and determination of corresponding revolutions per second.
Typical basket flowmeters are rated for 320 – 350°F (160 – 177°C) temperatures and 15,000 to 20,000 psia (103 to 138 mPa).
• 1.70-in (4.3 cm) tool accommodates 3,000 bbl/d (477 m3/d)
• 2.25-in (5.7 cm) tool: 5,000 bbl/d (795 m3/d)
• 3-in (7.6 cm) tool: 8,000 bbl/d (1272 m3/d)
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
29
Diverter Flowmeters
Diverter/Basket Flowmeter
Basket Size Small Large
Minimum Casing, in (cm) 4 ½ (11.4) 7 (17.8)
Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5)
Maximum Flow, bbl/d (m3/d) 1800 (286.2) 1000 (159)
Maximum Pressure (psi) 15000 (103 mPa)
Maximum Temperature (F) 350 (177 C)
Weight (lbs) Makeup Length (in) 60 (152 cm)
Maximum Flow (bbl/d)• Basket Open 2000 (318 m3/d)• Basket Closed 10000 (1589.9 m3/d)
Maximum Deviation () 60
Single phase (bbl/d) >100 (15.9 m3/d)
Qo in two phases (bbl/d) > 30 (4.8 m3/d)
Qw in two phases (bbl/d) >400 (63.6 m3/d)
Accuracy (%) 10
Exit Ports
Spinner
Hold-up Meter
Water Resistivity
Cell
DC Motor
The most accurate of the spinner devices when low total rates and multiphase flow occurs.
• Can detect flowrates as low as 10 to 15 bbl/d (1.6 to 2.4 m3/d).
– A typical 1-11/16-in (4.3 cm) tool has a barrel ID of approximately 1.45 in (3.9 cm).
– A flow of 10 bbl/d results in a velocity of 3.4 ft/min (1.04 m/min) inside the barrel.
– Because of the limited clearance between the spinner and the barrel, this velocity is enough to overcome friction and rotate the spinner.
– A flow of 100 B/D passes through the barrel at 34 ft/min (10.4 m/min) – enough to start the homogenization of the flow.
– In a casing, a rate of 2,000 bbl/d (318 m3/d)is needed to obtain the same effect around a continuous spinner.
– The tool can be calibrated directly for such flow.
Metal Petals
Small clearance between the spinner and the ID of the barrel assures almost no diversion of flow around the spinner.
As the spinner rotates, it generates a specific number of voltage pulses per revolution.
• The pulse rate from the tool can be transmitted through the logging cable for surface recording and determination of corresponding revolutions per second.
Typical basket flowmeters are rated for 320 – 350°F (160 – 177°C) temperatures and 15,000 to 20,000 psia (103 to 138 mPa).
• 1.70-in (4.3 cm) tool accommodates 3,000 bbl/d (477 m3/d)
• 2.25-in (5.7 cm) tool: 5,000 bbl/d (795 m3/d)
• 3-in (7.6 cm) tool: 8,000 bbl/d (1272 m3/d)
Measurements are made with the tool stationary.
The tool is lowered to the deepest measurement depth, then opened.
After recording the measurement depth, the tool is pulled up (while open) to the next measurement depth.
The risk of diverting flowmeter getting stuck in the hole is higher than it would be for a continuous flowmeter.
• If the tool is stuck, the cable can be pulled loose and retrieved.
• If the flowmeter is stuck in casing, it may be least expensive to leave the tool in the hole.
• If the flowmeter is stuck in tubing, it may be necessary to pull the tubing.
Spinner / Flowmeter Log Guidelines
Need to achieve stabilized flow rate
Calibrate tool
Record multiple passes at various speeds
Record stationary readings above and below perforations
Record repeat runs
The method is• Best for single-phase flow• Good for oil and water two-phase flow• Questionable under liquids and gas flow• Needs additional support (software, gauges, etc.) • Questionable for hole angles beyond 70°
Document all results
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
30_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Pressure Logging Tool
Usually contained within the same housing as the temperature tool
Sensor (strain or quartz gauge) measures absolute pressure at logging point
Its resolution is limited by a potentiometer transmitting device which causes pressure changes to appear as discrete steps on the recording
Limitation: Quartz crystals need to be well protected or risk damage
Data to be used in combination with other production logging tool components
Gradiomanometer
Measures pressure differentials• Pressure differential is the sum of:
– Hydrostatic head
– Friction head– The difference in kinetic effect between the 2 bellows
Mechanism requires calibration with a known fluid
At normal fluid velocities friction is very low, an unless there is a change in flow velocity between bellows, there is no kinetic effect
Pressure differential as seen by the gradiomanometer is usually only due to the average fluid density
Most effective for identifying gas entry and locating standing water levels
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
31
Gradiomanometer Components
Electronic cartridge
Transducer
Upper Sensing bellows
Slotted Housing
Floating connecting tube
Lower Sensing bellows
Expansion bellows
Spacing2 ft
(0.61 m)
Readings to be corrected for hole deviation and possible friction
Limitation: Application is of limited interest in highly deviated or horizontal wellbores when stratified flow is present
Gradiomanometer Components
Electronic cartridge
Transducer
Upper Sensing bellows
Slotted Housing
Floating connecting tube
Lower Sensing bellows
Expansion bellows
Spacing2 ft
(0.61 m)
Readings to be corrected for hole deviation and possible friction
Limitation: Application is of limited interest in highly deviated or horizontal wellbores when stratified flow is present
Hole deviation: Correction is applied by dividing reading by cosine of the deviation angle
Kinetic effect: Correction to absolute readings is required due to high downhole flow velocity
• Higher than 2000 bbl/d (318 m3/d) in 4-½" (11.4 cm) tubulars • Higher than 5000 bbl/d (795 m3/d) in 5-½" (14 cm) tubulars
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
32_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Gradiomanometer Log Interpretation
0.4 gm/ccFree gas + liquid
Zones
Hydrocarbon entry possibly with some water
Hydrocarbon entry possibly with some water
Gas or gas + liquidGas or gas + liquid
WaterWater
1.0 gm/cc water column either static
or moving
0.7 gm/cc oil, or gas + water, or oil + gas + water
ρw = 1.0 gm/ccρo = 0.7 gm/ccρg = 0.2 gm/cc
Production Combination Tool
PCT Logging Tool Specification• Fullbore Flowmeter• Gradiomanometer• Caliper• Manometer• Thermometer• Casing Collar Locator• Gamma Ray
Great progress in production logging has been made with the development of tools to work under dynamic conditions
Combinations of tools• Flowrate meter• Fluid identification devices• Depth controlCOPYRIG
HT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
33
Production Combination Tool (PCT)
PCT Logging Tool Specification• Fullbore Flowmeter• Gradiomanometer• Caliper• Manometer• Thermometer• Casing Collar Locator• Gamma Ray
In open hole, the presence of a caliper is essential.
In cased hole logs, it is useful to obtain a diagnosison the actual casing diameter.
When local conditions are unknown, this PCTconfiguration helps to record the maximum amount of relevant data to diagnose well flow conditions.
Run only those tools that are needed (‘Fit-for-purpose’ rather than ‘Nice-to-have’).
Flowmeter ‒ Quicklook Qualitative Analysis
Depthm
2310
2320
2330
2340
2350
2360
2370
2380
2390
2400
2410
2420
2430
2440
Z GRGAPI0 2000
CVELm/ min-40 40
SPINrps-11 15
CALin6.6 7.
WFDEg/ cc0.95 1.04
W TEP°C113.4 114
WPREpsia2100 2250
Possible corrosion
FluidEntries Fluid
Entries
FluidEntries
COPYRIGHT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
34_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.
Conventional Production Logging Summary
Essential recording tools for single- or two-phase flow:• Thermometer (Temperature log)
• Spinner flowmeter
• Gradiomanometer Density log
As a standard configuration downhole diagnosis tool, the CombinationLogging Tool usually includes:
• Thru-Tubing Caliper• Temperature log
• Spinner flowmeter
• Pressure log• Gradiomanometer Density log
Other logs include: • The Noise log is useful in specific applications to diagnose flow issues
• The Radioactive tracer is used in injection wells
• The Thermal Decay Time log (Pulsed Neutron) is a reservoir engineering tool to monitor water saturations over well life
All these tools provide valuable information to be analyzed by qualified analysts
Downhole Video Alternative to Production Logs
Advances in downhole video equipment now offer this measurement as an alternative to the new class of production logging measurements.
A downhole video log is a means to directly identify location of fluid entries into the well, because almost all production wells contain water through which the hydrocarbons are passing.
High rate water entries can also be detected from the image distortion caused by high levels of turbulence.
This approach is qualitative and does not fully replace production logging tools.
COPYRIGHT
═════════════════════════════════════════════════════════════════════════Production Logging Fundamentals
© PetroSkills, LLC., 2016. All rights reserved._____________________________________________________________________________________________
35
Downhole Video Alternative to Production Logs
Characterizing wellbore fluids Especially entry points
Inspecting downholemechanical equipment
Downhole Video Alternative to Production Logs
Supplement fishing services
Detect casing or tubing leaks
Spot mineral deposits
Find scale corrosion and bacterial buildup
Examine the condition of downhole equipment
Inspect the operation of downhole equipment
In open hole wells, rock formations are easily viewed by the camera
When drilling mud is used, mud is opaque and usually prohibits use of a video cameraCOPYRIG
HT
Downhole Production Logging Tools ═════════════════════════════════════════════════════════════════════════
36_____________________________________________________________________________________________
© PetroSkills, LLC., 2016. All rights reserved.