SPE 7774 - Noise Logs as a Downhole Diagnostic Tool.pdf

7/24/2019 SPE 7774 - Noise Logs as a Downhole Diagnostic Tool.pdf

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SPE

SPE7774

USEOFTHENOI SELOGASADWNHOLEDI AGNOSTI COOL

byH. B. iksmer, Jr.,and J. C. Carroll,

MembersSPE-AIME,ArabfanAmericanOil Co.

~Copyright 1979.So@ety of Pet ro leumEngineers

T f ri spapar was p r esent eda t t heM i dd l e Eas t 011Techni ca l Con f e renceo f t he c l e t y o f R? t ro l eu f i :~ I nee rshe l d I nM anama, Sahra l n, 25 . 2SM ar ch1979. Tha m ate r ia l i ssub j ec t t oco r r ec t i onby t heau t ho r .

Ie r mi ssi on t o copy I s r aat r l c t ed t o an abst r ac t o f no t m ore t han3DDwords . W ri t e SPE, 52W Nor th en lr a l Exp ressway, Da l l as , Texas 753LWUSA. Tel ax 730S6S(SPEDAL).

In all these cases the flow stream is in-

accessible,whioh rules out the use of a flow-

meter or RAT. The temperaturelog is ineffective

Flow @f aquiferwater intoa dry oil produc-

because either the flow rate is too small to

tionstream,contaminationf freshwateraquifers

effect a gradient change or the temperatut-e

due to casingleaksor orossflowbehindpipe,and

of the flowingfluidis indistinguishableromthe

loss of oil, naturalgas, or inJeotionfluidsdue

wellboretemperature.Sinoe 1976, oowever,ARAMCO

to downhole equipmentfailuresare examples of

has been using a noise logging technique to

everyday probleme in a l~~ge oil producing

successfullyevaluateproblemssimilarto these.

operation.

These problems must be detected,

oonfirmed, diagnosed and solved - quickly and

economically. Collection of useful downhole

informationis the key to meeting this require-

ment.

reoog%ec%%% Y&?S TYhcle~OE E

until 1972, however,

that the results of an

Conventional logging techniques such as

extensivelaboratoryInvestigationnt~the nature

temperature,flow-meterand radio-activetracer

(RAT)are used effectivelyfor detectingundesir-

of downhole noises were reported.

Using

these thesereeultstwo importantconclusionswere

able fluid flow in a wellbore. However, in drawn:

ARAMCO operations, situations are frequently

encounteredwhere these tec hnlquesre partially

1) That order of magnitudefl ow rates can be

or totallyinadequate,for example:

estimatedusingpeak noise;and

1) Oil producerwatersout.Temperatureprofile

2) That aertainflowsituationscan be disting-

is normal.

Tubing is set to TD. Source of

uishedfromothersif the frequencystructure

wateris questionable.

of the noisecan be obtained.

2) Producerwith tubingrun to TD developspres-

The developmentof a downholenoise logging

sure on a oashg - casingannulus,

Tempera-

techniquewas undertakenbased on these conolu-

tureprofileshowsno anomalies.

Siona.

The groundworkhas been laid for quanti-

tative interpretationof downholenoise,but, to

3) Supplywellsproduaing120 MB/D of 170 Sal-

date, most interpretationsre stillqualitative.

ine aquifer water by electrically driven

submersiblepumps hung at 500 ft on a water

columnmust be monitoredroutinelyto prevent

Oontamlnatlon of fresh water aquifers.

4) Power water inJeotionwell developea well-

Our observationsindicatethatabsolutenoise

boreobstruction.The obstructionis opposite

amplltude is the key to qualitative noise log

the top of a largeaquiferwhose temperature

interpretation, sinoe noise peaks are usually

is the same as that of the water being

deteotedoppositea noise souroe,and the energy

injected.

levels of these peaks indicate the severity

of the problem. Whereaemorepreoisequantitative

interpretationrequires additionaland improved

References and illustrations at end of paper


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feedbaok.

Before noise logs from different

situations are oompared~ .t is important to

know that the noise Smplitw esreoordedon the

logs are highlyaffeotedby the configurationand

fluidcontentof thewellbore.

The amplitude of a noise detected through two

stringsof pipewill be lessthanthat of the same

noisedeteotedthroughone string.

The prinoiple

is simple,the more metal,the greaterthe atten-

uationof the noise. Similarly,noiseattenuation

is greaterin gas thenit isin water. It follows

that the noise level of a 30 MBD annular flow

detectedin gas filledtubingwould be less than

if it were detected in liquid filled tubing.

Noise amplitudesin the wellboreare sometimes

distortedor maskedby noiseoarry-away.Noiseis

transmittedaway from its sourceby gas, liquid,

metal,etc. Attenuationof oarry-awaycan result

in some interesting noise log characteristics

(seeFigure1).

High frequer?ciesttenuatefaster

than lower frequencies.This faot permitsa high

energynoise sourceto be looatedwith much more

precision. A strik;nganomaly is created by a

fluid levelabove A large noisesouroe.The noise

Is c arriedawav with little attenuationin the

liquid,but when the deteotoris raisedInto the

gas,the nq selevelis reduoedconsiderably.If,

for example,a sharp changein the 200 HZ ampli-

tude ooaurs, a fluid level should be suspected.

In the lab a detailed noise spectrum of a

particular flow situation can be generated by

measuringthe noise amplitudeof numerous freq-

uenay bands (see Figure2).

In practicalfield

applicationthe noisespectrummuet be limitedto

a reasonable number of frequency bands.

Most

surfacepanels in use today have filtercircuite

for 200, 600, 1000and 20CJ0HZ.

These cuts were

selectedfor the followingreasone:

i)Noise below 200 HZ, which includes most

equipment related noises, are of limited

usefulness.

2) Large amounteof energyfrom two-phaseflow

situationsare concentratedin the 200-600

HZ band.

3) SinglephaseflowIs characterizedby maximum

amplitude in the 1000 HZ region, shifting

towards 2000 HZ as ?ressure differentials

Lnorease.

Some surfaoe units are equipped with 4000 and

6000 HZ filters.These filterspermit the isola-

tion of the high frequenoyenergycausedby sand

pinging.

The deteotion sondes used by ARAMCO were

developedand built by EXXON PRODUCTIONRESEARCH

co.

The standard sonde is I-11/16 inches in

diameter,and a speciaSaonde built for logging

throughgas lift mandrelsis 1 inoh in diameter.

Bothtoolsare about3 ft. long.

Piezoeleatrioorystalsare used to convert

noise vibrationsinto en AC signal.

This signal

Is driven up a eingle eonduator cable (with a

sheathreturn)by a transistorizedmplifier. At

the surfaaethe AC signal is amplified,filtered

and the peek-to-peakAC millivoltnoise level ie

measured, High Zidelityis a neoessity.

Extra-

ordinary oable lsngths (>10,000 ft) oan aause

exaessive attenuation or distortion of the AC

signal. Some surfaoepanelemeasurepeak milli-

volts or RMS millivoltsrather than P-P milli-

volt. Amplitudesmustbe correctedif comparisons

are beingmade or standardcorrelationsare being

ueed.

The sonde Is run in the hole with a baslo

winoh truck spooledwith 7/32 Inch monoconductor

cable. Lubricator equipment is standard for

1-11/16Inohtools. Measurementof noieelevelsie

done with the sonde stationary. The reasonfor

this should be obvioue i f you*ve ever dropped

an operating microphone.

Some of the logging

truoksavailableto us are equippedwithsophisti-

cated panelsthataveragethe noiselevelsof all

four frequencycuts simultaneouslyand provide

digital readout, while ctherv?require that

each frequenoybe measured separatelyend read

from an analogvoltmeter. Stabilizationtime for

each station will average about one minute.

Millivolt readingsare plottedon a log scalevs

depth. Stationsare predetermine~.Any anomalies

are repeatedand further defined by additional

stopeif necessary.

Our use of noise logginghas been strictly

qualitative.Any quantitativework hae been for

academicpurposesonly. Most of our problemscan

be solvedby recognizinganomalousnoisepeaksand

describingthe flow situationbased.onthe loca-

tLonand smpl~tudeof thesepeaks.

Few wells in Saudi Arabia will provide a

noiselog llkethe one presentedin Figure3. It

is probablysafe to say that therewas no uncon-

trolledfluidflowin this well when the log was

recorded. Manywellsexhibitcomenoisecharacter

whether or not a problem existe.

It iS 108S

like the one in Figure 4 that test an inter-

preters knowledgeand ability.

This noise log

was an unsuccessfulattemptto confirma suspected

liner lap leak which had been indicated by a

continuousflowmeter.

The well, used to indeot

desaltingwaste water,was workedover to ensure

that contaminationof aquiferswas not occurring.

Tressure teetingdid not revealthe exlstenoeof

any leaks.

The resultsof many successfulapplications

of noise loggingby ty rest of the oil induetry

have been documented.

Presented here are four

examples taken from our files that illustrate

ARAMCOIS use of the noise log as a downhole

diagnostict?ol. Theee examplesalso show that

major problems,the ones thatneed to be deteoted

and solvedquickly,are easilydeteotedusingthe

noiselog.


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however, detest a standing fluid level in the

tubingjustbelow3494 ft. and indicatedthat the

fluidwas 0%1.

The firstexample(seeFigure5) was recorded

in the tubingof an openhole 011 producerin the

The noise log presented in Figure 6 was

Ghawar Field.

The oompletlonis typical- 9-5/8

inchintermediateeasingcementedin two stages,a

recordedwith the 9-5/8 In. X 13-3/8in. annulus

flowinggas to flareat 15 psig. The interpreta-

7 inchlinerto the top of the produainginterval,

t.~~fif this

log stated

that leaks existed

and 2-3/8 inch tubing run just off bottomas a

kill string.

This well producedapprezirzately

oppositethe noisepeeksat 1600 ft. and 3500 ft.

5000 BID of dry oil through the tu5ing casing

During the workover to eliminate the annulus

pressure,

the only leak detectedwas at 1600 ft.

annulusuntilit died in 1976.

After the well died, the followinglnforma-

The noise peak at 3500 ft was due to the

exissenceof a fluid leveland gas roilingat the

tionwas collected:

gas/oilinterface. The gas evolvingfrom the oil

1) Shut in wellheadpressurewas zero psig.

was flowingup the wellboreto 1600 ft where it

was enteringthe 9-5/8 in. X 13-3/8 in. annulus

through a failed DVn tool. From there it

2) PressureprofileIndicateda water/oiloon-

flowedup theannulusto flare.

tactin the tubingat 5800 ft.

3) Temperaturesurvey ~howedno anomalles.

Availableevidenceshouldhave indicatedthat

a leek did not exist at 3500 ft.

The pressureof

4) Bailersampletakenat 6700 ft was 98% water

theaquiferat thisdepthwas 1460psig,whilethe

(TDS=76,000ppm).

pressure measured in the wellbore

during a

gradientsurveywas 1259 pslg. The potentialfor

flow was towar~s the wellbore, however, oil

5) Swabbingrecovered200 bb%s fluid,10% oil

productionwas dry.

- 905 water.

6) Finalfluidlevelafterswabbingwas about

2500 ft.

Much of the aquiferwaterfarhaterinjection

It was suspectedthat thewaterscurcewas s.n

projeatais euppliedby waterwellsequippedwith

submersiblepump installations.

A typicalwater

aquiferdumping from a casing leak.

The noise-

loggerwas run in the hole to attemptto pinpoint

supplywell is completedopen hole with 20 inch

the water source. Stops were made at 100 ft.

casingoementedat 1000ft, 13-3/8inchlinerfrom

800 ft. to 3450 ft. and a 9-5/8 inch liner from

stations to measure the amplitudescf the four

3000 ft to the top of the produoing aquifer.

standardfrequencycuts.

The submersiblepump and electricdriverare hung

on 10 inch water columna~5000ft.

These pumps

There is an obvious noise peak at 4800 ft.

The peak is oppositea large, prolificaquifer.

will lift 120 MBD of 160 -170F saline aquifer

The evenspacingcf the frequencycurvesindicates

waterat 120 psigFWHP,and the wellswill flow90

MBD to the atmosphere.

that the leak was singlephase.

No attemptwas

made to calculatethe leakrate.

The absenceof a

All supplywells are compietedwith major,

temperature anomaly indicated that the leak fresh-wateraquifersbehind the surface casing.

ratewas small.

Many of the wells are locatedon the edge of a

large oasis that depends on the fresh water

A workover to repair the 7 inch liner waa

produced from these aquifers.

Protecting the

recommendedbased on the informationsuppliedby

the noise log. Subsequentpressuretestingwith

aquifers from contamination requires that the

drillpipeand a peckerconfirmedthe existenceof

wells be m~nitored routinelyfor shallow casing

leaks.

a leak at 4800 ft.

The casing was repaired,

and thewell returnedto production.

A radioactivetracersurveyis made wher%s?er

1200 nSIR ON THE 9-5/8 X 1?-?/8 A~

a failedsubmersiblepump assemblyIs pulletifrom

n

a well. Recently,hcwever,we have increasedthe

The well in this example (see Figure 6) is

average run life of these pumps so that it now

exceeds the acoepted routine survey period.

also an oil producerin the Ghawar Field.

The

Pulling water columns, changingout submersible

completionis typicalwith the DV stagetool in

the 9-5/8inchcasingat 1601ft.

pumps and especially electric drivers is an

expensive,time-consumingoperation.

Therefore,

A routineannulisurveydetected3 pressure

an alternativemethod for surveyingthese wells

was required.

of 1200 paig on the 9-5/8 X 13-3/8n annulus.

Shut-in tubing pressure was 1200 psig, while

Historically, nearly all casing leaks in

ehut-incasingpressurewas 1150 psig.

these water supply wells occur at or above the

pumpsuction. Aftershuttingdown the pump,it is

Attemptsto eliminatethe annuluspressureby

reworkingand repackingthe wellheadwere unsua-

possibleto run the noise sonde down the water

columnand recorda noieelog (seeFigure7). All

cessful.Temperatureand pressureprofilesmade

frequencycuts on this log increasefrcm surface

with the well shut in failedto revealthe source

to a peak at 150 ft. then remain constant or

of the problem.

The pressure profile did,

deoreaseslowly to 500 ft.

The absolutenoise

amplitudeis an indicationof fluid movementin


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194

USE OF 92SE

NOISELOG AS A ~WNHOLE DIAGNOSTICTOOL

SPE77?

-

-. .. .

I

the wellboreand the peakat 150 ft. was probably

been adequatelyresearchedand.documented.Three

caused by fluid aooeleratingaorose a restrio-

yesrsofoperationalexperiencewith the technique

tion. This well was worked over and a large

have providedus with an extensivebackgroundand

leakat 150 ft. repaired.

database; and basedon thieinfonnatlon,oonolu-

sionsare as follows:

~

1) Noise loggingcan be used effectivelyto

Figure8 is a noise log thatwas recorded in

deteot, confirm and diagnose downhole

a typioalpowerwater indeotionwell. ,Thiswell

problemsthathave reiadaredtherlogging

is a perforatedcompletionwith 9-5/8 Inoh casing

techniquesInadequate.

oementedat 4794 ft. and a 7 inoh linerrun from

3642 ft. to TD.

Injectionratewas 50 MBD at 1150

2) Correot interpretationof any but the

pslg wellhead pressure.

The flowing wellhead

simplestnoise logs requires& thorough

temperaturewas 155 F.

understanding of noise logging funda-

mentals and a oompleteknowledgeof the

While running an ETT log In the hole an

problembeinginvestigated.

obstructionwaa encounteredat 4010 ft. Attempts

to get belowthe obstructionwitha flowmeterwere

unsuccessful.A temperatureprofilewas obtained

from the obstructionto aurfaoe.The anomolyat

200-850 ft. was not related to this problem,

The authors wish to thank the Arabian

and there were no anomaliesin the area of the

AmericanOil Company for pc.missionto publish

obstruction.Tools were run to 3800 ft. only to

thispaper.

prevent them from

getting

oaught up in the

obstruction.

The noiselogwas recordedwith thewell shut

in. Stations were every one hundred feet from

1. Enright, R. J.:

Sleuthfor Down-HoleLeakstt

surfaoeto the obstruction. The amplitudesnear ~ (Feb. 28, 1955) 78-79.

surfac eere quite high and they increaseddrama-

ticallyas the tool approachedthe obstruction.

2. Korotaev,Yu. P. and Babalcw,M.A.:

lAcous-

It was known that the reservoirpressureof the

tio Method of DelineatingOperatingIntervals

injeotlon zone was high enough to baokflow to

in Gas Bearing Formationsn, ~azovava PrQM

aquifersin the vicinity

of

the obstruction

f a

Nov., 1970).

leakexisted.

3. Stein, N., Kelly, J., Baldwin, W. F., and

The extremely high noise levels (200 HZ

McNeely, W. E.:

Sand ProductionDetermined

overranged)

aonflrmed that flow was ooourring

from Noise Measurementst , J. Pet. Tea~.

below the obstruction.(No additionalinformation

(July,1972)803-806.

can be obtainedfromthis log).

4. McKinley,R.M.,Bower,F.M.,and Rumble,R.C.:

Duringworkoveroperationsit was determined

The Struoture and Interpretation of Noise

that the well was baokflowing30 MBD into a leak

From Behind Cemented Casingff,J. Pet.Teti.

just belowthe obstruction.The leakwas repaired

Teoh. (Maroh 1973) 329-338; Trans., AtME,

and thewellreturnedto indeotionstatus.

255.

5. Robinson,W.S., FieldReeultsFrom The Nolse-

Logglng Technique ,

.,Nov. 1976)

The basicfundamentalsof noiselogginghave

1370-1376.

...


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SPE 7774 - Noise Logs as a Downhole Diagnostic Tool.pdf

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