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Acoustic Liquid LevelTesting of Gas Wells
Acoustic Liquid LevelAcoustic Liquid LevelTesting of Gas WellsTesting of Gas Wells
Lynn RowlanLynn Rowlan
European Conference Gas Well DeliquificationEuropean Conference Gas Well Deliquification
2828--30 September 2009, Hampshire Hotel, The Netherlands30 September 2009, Hampshire Hotel, The Netherlands
Originally Presented OKC POS 2009 - SPE 120643
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Acoustic Fluid LevelsAcoustic Fluid Levels
Traditionally Fluid Level shotTraditionally Fluid Level shot
down the annulus where tubingdown the annulus where tubing
collars are counted to determinecollars are counted to determinedepthdepth
Acoustic liquid levelsAcoustic liquid levels typicallytypicallyused for:used for:
Well Potential and BHPsWell Potential and BHPs
Artificial Lift OptimizationArtificial Lift Optimization
Plunger trackingPlunger tracking
Gas Well and Liquid Loading DiagnosticsGas Well and Liquid Loading Diagnostics
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Fluid Level
on Gas Well
Fluid Level
on Gas Well
Gas Velocity Impacts Result ofGas Velocity Impacts Result of
Acoustic Liquid Level Shot:Acoustic Liquid Level Shot:
1.1. Below Critical Velocity:Below Critical Velocity:
Usually see liquid levelUsually see liquid levelabove bottom of Tubingabove bottom of Tubing
2.2. Above Critical Velocity:Above Critical Velocity: May not see a liquid levelMay not see a liquid level
because liquid dropletsbecause liquid droplets
may fill tubing and absorbmay fill tubing and absorb
all energy from shotall energy from shot
May see bottom of tubingMay see bottom of tubing
and/or perforations due toand/or perforations due to
small amount of liquidsmall amount of liquid
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Acoustic Fluid LevelAcoustic Fluid LevelGenerate Blast atGenerate Blast at
Surface to CreatesSurface to CreatesTraveling WaveTraveling Wave
Acoustic WaveAcoustic WaveTravels in the WellTravels in the Wellat Speed of Soundat Speed of Sound
Echoes RTTT fromEchoes RTTT fromwell bore changewell bore changediameter recordeddiameter recorded Reduction seen as aReduction seen as a
downdown--kickkick Increase is seen as anIncrease is seen as an
upup--kickkick
Fluid level gives largeFluid level gives largekick and lets almost nokick and lets almost noenergy throughenergy through
CollarsCollars
LevelLevel
BA
NG!
BA
NG!
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Gas Gun Physical set-up on WellGas Gun Physical setGas Gun Physical set--up on Wellup on Well
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Display of Reflections of Pressure WaveDisplay of Reflections of Pressure WaveDisplay of Reflections of Pressure Wave
Reflected PulseReflected Pulse
caused bycaused byDECREASEDECREASE in thein theannular crossannular cross--sectional areasectional area ISISdisplayed as andisplayed as an
downward kickdownward kick ononthe acoustic trace.the acoustic trace.
Initial Acoustic PulseInitial Acoustic Pulse caused by explosion of compressed gas into the tubingcaused by explosion of compressed gas into the tubingor casing annulus, explosion into annulus forms compression travor casing annulus, explosion into annulus forms compression traveling wave.eling wave.
Reflected PulseReflected Pulse
caused bycaused byINCREASEINCREASE in thein theannular crossannular cross--sectional areasectional area ISISdisplayed as andisplayed as an
upward kickupward kick on theon theacoustic trace.acoustic trace.
Acoustic Trace AcquiredAcoustic Trace Acquired
down the Tubing Showingdown the Tubing Showing
Upkick from Hole in TubingUpkick from Hole in Tubing
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Shot Down TubingVerify Liquid Level Above/Below Tubing Inlet
Shot Down TubingShot Down TubingVerify Liquid Level Above/Below Tubing InletVerify Liquid Level Above/Below Tubing Inlet
End ofEnd ofTubingTubing
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Use an Acoustic Fluid Level Instrument
To Identify The Depth To The Hole
Use an Acoustic Fluid Level InstrumentUse an Acoustic Fluid Level Instrument
To Identify The Depth To The HoleTo Identify The Depth To The Hole1.1. ShootShoot
tubing/casingtubing/casingannulus whileannulus whileflowing upflowing uptubingtubing
With CasingWith CasingValve ClosedValve Closedthe Fluid Levelthe Fluid Level
should be nearshould be neartubing intaketubing intakeor belowor belowperforations (Ifperforations (Ifno Hole)no Hole)
??
Time 12:12:27Time 12:12:27
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Shots Down Tubing & CasingShots Down Tubing & CasingShots Down Tubing & Casing
Hole in TubingHole in Tubing
@ 6868@ 6868
Tubing ShotTubing Shot Casing ShotCasing Shot
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Use Acoustic Surveys to
Alert You to What is Downhole
Use Acoustic Surveys toUse Acoustic Surveys to
Alert You to What is DownholeAlert You to What is Downhole
@ 4750@ 4750Tight SpotTight Spot
in Tubingin Tubing
@ 5050@ 5050
1/81/8 HoleHolein Tubingin Tubing
Tight SpotTight Spot
1/81/8 HoleHole
LiquidLiquid
LevelLevel
End ofEnd of
TubingTubing
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Liquid Level Depth (LL) determined by multiplying the RTTTLiquid Level Depth (LL) determined by multiplying the RTTT
(Seconds) by the average of all collars counted (JTS/sec) times(Seconds) by the average of all collars counted (JTS/sec) times thetheaverage joint length (Feet). (5.566*20.5725*31.670 = 3626.41 feaverage joint length (Feet). (5.566*20.5725*31.670 = 3626.41 feet)et)
Acoustic Trace with Depth DeterminationAcoustic Trace with Depth DeterminationAcoustic Trace with Depth Determination
Collars count depthCollars count depth
(C) is noted on the(C) is noted on the
acoustic signal.acoustic signal.
Liquid LevelLiquid Level
Depth (LL)Depth (LL)1 Sec1 Sec
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Analysis Method: Automatic Collar CountAnalysis Method: Automatic Collar CountAnalysis Method: Automatic Collar Count
Automatic Collar Count analysis will determine the depth to theAutomatic Collar Count analysis will determine the depth to theliquid level for most wellsliquid level for most wells
00
3030 4040
20201010
4646
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Downhole Marker Using Known Perforation Depth
to Determine Distance to the Liquid Level
Downhole Marker Using Known Perforation Depth
to Determine Distance to the Liquid Level
1.921 sec1.921 sec
1369 ft1369 ft
? = 1875 ft? = 1875 ft2.631 sec2.631 sec
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Offshore Wellbore Schematic and Corresponding Acoustic TraceOffshore Wellbore Schematic and Corresponding Acoustic TraceOffshore Wellbore Schematic and Corresponding Acoustic Trace
Offshore Wells:Offshore Wells:1) Use of Downhole1) Use of Downhole
Markers most oftenMarkers most often
used analysisused analysis
Method..Method..
2) Acoustic Velocity2) Acoustic Velocity
Method often usedMethod often used
initially to identifyinitially to identify
general location ofgeneral location of
Known MarkersKnown Markers
3) Should use Deepest3) Should use Deepest
Marker for Depth toMarker for Depth toLiquid LevelLiquid Level
4) Data Always Critical4) Data Always Critical
in Calculation ofin Calculation of
BHPBHP
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Analysis Method: Low Pass Filter Identifies
Downhole Marker Gas Lift Mandrel
Analysis Method: Low Pass Filter IdentifiesAnalysis Method: Low Pass Filter Identifies
Downhole MarkerDownhole Marker Gas Lift MandrelGas Lift Mandrel
See DownholeSee Downhole
Anomalies:Anomalies:
SCSSV@ 1575SCSSV@ 1575
XX--NIPL@ 3161NIPL@ 3161
GLM1@ 3618GLM1@ 3618
GLM2@ 11743GLM2@ 11743BHP Ch@ 11798BHP Ch@ 11798
CIM@ 11874CIM@ 11874
XX--NIPL@ 11993NIPL@ 11993
XO@ 12041XO@ 12041
XNXN--NIPL@ 12374NIPL@ 12374
LiquidLiquid
LevelLevelSCSSVSCSSV GLM1GLM1
HighHigh
FrequencyFrequency
NoiseNoise
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Depth Determination:Depth Determination:Acoustic VelocityAcoustic Velocity methodmethod
Depends on:Depends on:
1.1. Gas gravity / compositionGas gravity / composition
2.2. Temperature along completionTemperature along completion
3.3. Pressure in the completionPressure in the completion
(automatically calculated from(automatically calculated from
measurements taken during themeasurements taken during the
shots)shots)
4.4. May use Casing Shot for Tubing SGMay use Casing Shot for Tubing SG
Acoustic Velocity options:Acoustic Velocity options: Manually enteredManually entered
Calculated based on SG of gasCalculated based on SG of gas
Calculated based on compositionalCalculated based on compositional
analysisanalysis
(Manual gas velocity can be used for(Manual gas velocity can be used for
approximations or in case whereapproximations or in case where
velocity already determined byvelocity already determined by
downhole marker correlation in otherdownhole marker correlation in other
shot)shot)
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Gas flowing into wellGas flowing into well
Tested Gas Production = 265 MCF/DTested Gas Production = 265 MCF/D
358358
psipsi
FBHP = 1080.6 psiFBHP = 1080.6 psi
Closed Valve 2.5 Min. to
Determined Gas Flow
Rate and % Liquid
dP/dT Gaseous Correction
86368636 Gaseous HeightGaseous Height
Adjusted Gas FreeAdjusted Gas FreeGaseousGaseous
16151615GasGas
FreeFree
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Gas flowing into well
61.7
psi
PBHP = 373.9 psi
3427
Da, Adj. Gas Free HeightDa, Adj. Gas Free HeightGaseous
Da*dP/dTDa*dP/dT
= 61813= 61813
Da = 9719Da = 9719
DetermineDetermine% Liquid% Liquid
16151615GasGas
FreeFree
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Backpressure in a Liquid Loaded WellBackpressure in a Liquid Loaded WellBackpressure in a Liquid Loaded Well
LiquidLiquid
LevelLevel
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Fluid Level Results on Gas Well Treated with
Surfactant Foam 1/3 of Gaseous Liquid Gradient
Fluid Level Results on Gas Well Treated with
Surfactant Foam 1/3 of Gaseous Liquid Gradient
?? -- %Liquid%Liquid
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Static Fluid Level on Gas WellStatic Fluid Level on Gas WellStatic Fluid Level on Gas Well
Measured SurfaceMeasured SurfacePressure 2249.5 PsigPressure 2249.5 Psig
365.8 Psig Gas Column365.8 Psig Gas ColumnPressurePressure
High Pressure GasHigh Pressure Gas
Pushed all but 87.8 ft ofPushed all but 87.8 ft ofLiquid Back intoLiquid Back intoFormationFormation
Easy to Observe UpEasy to Observe Up--kickkickcaused by the top perfs atcaused by the top perfs at6032 feet (Next Slide)6032 feet (Next Slide)
Collar Recesses CountedCollar Recesses Countedto Perforationsto Perforations
ShutShut--inin
Gas WellGas Well
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-LL
0 1 2 3 4 5 6 7 8 9 10Sec
Implosion
100.0m
V
( ft ) 0 1000 2000 3000 4000 5000 6000 7000
C -
Acoustic Trace From
Static Fluid Level on Gas Well
Acoustic Trace FromAcoustic Trace From
Static Fluid Level on Gas WellStatic Fluid Level on Gas WellCollar RecessesCollar RecessesCounted toCounted toPerforationsPerforations
778 Sec8 Sec
778 Sec8 Sec
Collar RecessesCollar RecessesNot Seen @ LowNot Seen @ LowPressure OR inPressure OR in
Flush JointFlush JointTubingTubing
BUTBUT
See Clearly @See Clearly @High PressureHigh Pressure
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-LL
0 1 2 3 4 5 6 7 8 9 10Sec
Implosion
100.0m
V
( ft ) 0 1000 2000 3000 4000 5000 6000 7000
C -
Analysis Method :
Counting Collars versus Using Top of
Perforations as Known Marker Depth
Analysis Method :Analysis Method :
Counting Collars versus Using Top ofCounting Collars versus Using Top of
Perforations as Known Marker DepthPerforations as Known Marker Depth
Collar RecessesCollar RecessesCounted to PerforationsCounted to Perforations
Depth to LL = 6162.22Depth to LL = 6162.22
-LL
0 1 2 3 4 5 6 7 8 9 10Sec
Implosion
100.0
mV
( ft ) 0 1000 2000 3000 4000 5000 6000 7000
-DM
Depth to LL = 6164.21Depth to LL = 6164.21
6032 ft to Top6032 ft to Topof Perforationsof Perforations
Acoustic Velocity = 1420Acoustic Velocity = 1420 --1500 ft/sec1500 ft/sec
Comparison of Two Methods shows Depth to Liquid Level within 2 FComparison of Two Methods shows Depth to Liquid Level within 2 Feeteet
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General CommentsGeneral CommentsGeneral Comments
1)1) Acoustic fluid level measurements are easilyAcoustic fluid level measurements are easilyperformed in flowing or shut in gas wellsperformed in flowing or shut in gas wells
2)2) Recommended practice is to always acquire atRecommended practice is to always acquire at
least two (2) acoustic fluid level records whenleast two (2) acoustic fluid level records whenconnected to a wellconnected to a well
3)3) When shooting down the tubing, EUE collarWhen shooting down the tubing, EUE collar
recess Echoes can often be detectedrecess Echoes can often be detected4)4) Using an echo from a known down hole markerUsing an echo from a known down hole marker
near the fluid level is usually the most accuratenear the fluid level is usually the most accuratemethod to determine depth.method to determine depth.
5)5) Using gas specific gravity or composition isUsing gas specific gravity or composition isoften the least accurate depth determinationoften the least accurate depth determinationanalysis methodanalysis method
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Questions ?Questions ?
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