20_ Acoustic Liquid Level Testing of Gas Wells

7/24/2019 20_ Acoustic Liquid Level Testing of Gas Wells

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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 ?

20_ Acoustic Liquid Level Testing of Gas Wells

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