Lab 5 Reservoir Fluid Studies

8/12/2019 Lab 5 Reservoir Fluid Studies

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Reservoir Fluids

PETE 310

Lab 5: Reservoir Fluid Studies

Constant Composition Expansion, Differential Vaporization, and

Separator Tests of a Live Oil Sample

Learning Objectives

Simulatethe

PVT

tests

mentioned

above

using

the

PVTSimulator

Lab5.xls

available

from

our

websiteand:

1. UsePVTdatafromaCCEtesttodeterminebubblepointpressureandoilcompressibility

abovethebubblepoint.

2. InterpretPVTdataobtainedfromaDLtesttodetermineBoDandRsDanddiscusstheeffectsuponthesepropertiesbyusingdifferentpressuredecrements.

3. Understandtheimportanceofselectingoptimalseparator(s)pressureandtemperature

tomaximizeoilproduction.

4. Usecombined

CCE,

DL,

and

separator

data

to

produce

corrected

formation

volume

factorsandsolutiongasoilratiosforreservoirengineeringcomputations

General Skills

1. KnowhowtooperateourexcelPVTsimulator

2. Calculaterelationshipsbetweenmoles,mass,andmolecularweight.

3. ConvertbetweenAPIgravitytospecificgravityand/oroildensity.

4. Workwithdifferentsystemsofunitsandconvertonesettoanother.

Background Material

LecturesReservoirFluidStudyReportandReservoirFluidStudyLabProcedure fromour

classnotes(October19and21inSyllabus),andChapter10pages257to280fromMcCain

ReservoirFluidsbook.

FollowthislinkforadditionalinformationonPVTequipment
http://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asphttp://www.slb.com/content/services/testing/reservoir/pvt_equipment.asp


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Lab # 5 Tutorial Example

How to Process PVT Information from CCE, DL, and

Separator Tests

Thefollowing

example

guides

you

on

how

to

use

and

interpret

the

data

from

aCCE,

aDL

test

andaseparatortest.ThereservoirtemperatureisT=220oFandtheinitialreservoirpressureis

2200psia.

Arecordedpresentationwithhintsprovidesdetailsonhowtousetheexcelfile.Thistutorial

presentsthedataobtainedandthecalculationswiththedata.

Fig. 1Compositi onal information allows users to enter the number of moles of

each component.

Constant Composition Expansion (CCE) Results

Table1shows

the

CCE

data

with

pressure

steps

of

100

psia,

here

the

experiment

ends

at

1,600

psia.

Theoutputtabledisplaystheliquidandvaporfraction,thecompressibilityfactor,andthe

volumesofoilandgasateachpressurestage. Fromthistableyoucanfindthebubblepoint

pressuregraphicallyornumericallyasindicatedinclass.

Table 1Constant Composition Expansion Results

Pressure fo fg zo zg Vo, cm Vg, cm

2200.0 1.0000 0.0000 1.0951 0.0000 30.3196 0.0000

2100.0 1.0000 0.0000 1.0466 0.0000 30.3562 0.0000

1995.5 1.0000 0.0000 0.9958 0.8989 30.3952 0.0001

1800.0 0.9502 0.0498 0.9335 0.9013 30.0161 1.5177

1600.0 0.9012 0.0988 0.8640 0.9050 29.6407 3.4032

Lab#5 PETE 310


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FromTable1wecanseethatthebubblepointpressureforthismixtureisbetween2100an1800psia.Refiningthesearchprovidespb=1995psi,notethatatthispressurethevolumeof

gasobtainedisverysmall.

Differential Liberation

ThisexperimentbeginsatthebubblepointpressuredeterminedfromtheCCE. Theoilsampleis

subjecttoaseriesofexpansionsasindicatedinthelectures.

Forthisexamplethepressurestepsare500psia,youcanandwillhavetodiscusstheeffectof

thesizeofpressuredecrementsinthecomputedproperties. Onestageat14.7psiaand

reservoirtemperatureand anotherstageat14.7psiaand60Fareautomaticallyaddedintothe

experiment.

Table2displaysthedifferentialliberationresultsforourexamplemixture.Thisoutputincludesthefractionofliquidandvapor,thecompressibilityfactor,andthevolumeofoilandgasatthe

specifiedpressureandtemperature.Thisvolumeofgasisremovedfromthecellbeforethenext

expansion.UsingdatafromthistableyoucancomputeRsd,Bod, andBgusingtheprocedureexplainedinclass.

Table 2Different ial Liberation resu lts at T=220oF

Pressure,

psi fo fg zo zg Vo, cm3

Vg, cm3

1995.5 1.0000 0.0000 0.9958 0.8989 30.3952 0.0001

1500.0 0.8774 0.1226 0.8268 0.9075 29.4571 4.5187

1000.0 0.8720 0.1280 0.6135 0.9249 28.5852 6.3285

500.0 0.8634 0.1366 0.3449 0.9518 27.7497 12.1138

14.7 0.7850 0.2150 0.0122 0.9946 26.2210 585.2771

14.7 (at 60F) 1.0000 0.0000 0.0154 0.0000 25.3069 0.0000

Separator Tests

Theobjectivesoftheseparatortestsaretooptimizetheamountofoilproducedatthesurface.

Youwillconducttestswithoneandtwoseparators;yourgoalistofindthebestpressureand

temperaturecombinations(foroneormultipleseparators)thatmaximizeliquidproduction.The

stocktank,whichactsasanotherseparatoratstandardtemperatureandpressure,isincluded

automaticallyinyourcomputation.

Lab#5 PETE 310


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Thegoaloftheoneseparatortestistofindtheseparationpressureandtemperaturesuchthat

thesolutiongasoilratioatthebubblepointisaminimum,theAPIgravityoftheoilatstocktank

conditionsisamaximum,andtheformationvolumefactoratthebubblepoint(BoSb)isa

minimum.

One Separator Test Results

Table3showsthePVTpropertiesfromtheexamplemixtureatitsbubblepoint(computedearlier)andataseparatorpressureandtemperatureof150psiaand100oF. Thestandardstate

computationisaddedautomatically.

Table 3Single-Separator Test Results

p, psia T, F fo fg zo zg Vo, cm Vg, cm o, lb/f t o, lb/ft

1995.5 220 1.0000 0.0000 0.9958 0.8989 30.3952 0.0001 42.0204 5.4995

150 100 0.6069 0.3931 0.1306 0.9725 26.4932 127.8482 45.8975 0.4791

14.7 60 0.9328 0.0672 0.0145 0.9944 25.9637 128.5327 46.5212 0.0631

ThecorrespondingPVTpropertiesfromtheseparatortestarecomputedasfollows

STO

bbl170.1

cm9637.25

cm3952.303

3

==oSbB............................................................................ (1)

Thevolumeofgasfromtheseparatoratstandardconditionsis

( )( )

cm64.1245psia7.14

R46060

R4601009725.0

cm127.8482psia150 33

=+

+==

sc

sc

SS

SS

scP

T

TZ

VPV (2)

Thesolutiongasoilratiooftheseparatoristhen

STO

SCF162297STO

SCF6145cm963725

cm5327128cm641245R 3

33

sSb ...

..=

=

(3)

o(Tsc,psc) =46.52lbm/ft3 29.585.131

4.62

5212.46

5.141API == (4)

Lab#5 PETE 310


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Two Separators

Theobjectivehereisthesameaswithoneseparator(obtainamaximumAPIgravityoil),but

hereyouneedtooptimizethepressureandtemperatureoftwoseparators.Weusetheoutput

fromoneoftheseteststoillustratethecalculationprocedure.

Table 4Two-Separator Test Results

p, psia T, F fo fg zo zg vo, cm vg, cm o, lb/ft g, lb/ft

1995.5 220 1.0000 0.0000 0.9958 0.8989 30.3952 0.0001 42.0204 5.4995

500.0 100 0.7136 0.2864 0.3810 0.9219 27.2734 26.4860 45.2832 1.5931

100.0 80 0.8465 0.1535 0.0903 0.9770 26.3862 51.7565 46.1277 0.3457

14.7 60 0.9451 0.0549 0.0144 0.9935 26.0221 104.3192 46.5016 0.0677

InthisexamplewechoseSeparator1at500psiaand100oFandSeparator2at100psiaand

80oF.

ThePVTpropertiesforthistestarethen:

STO

bbl168.1

cm0221.62

cm0.395233

3

==oSbB. ......................................................................... (5)

Thevolume

of

gas

released

from

each

separator

atstandardconditionsis:

( )( )

m4.907psia7.14

R46060

R4601009219.0

cm26.4860psia500 33

1 cP

T

TZ

VPV

sc

sc

SS

SS

sc =+

+==

................. (6)

( )

( )m02.347

psia7.14

R46060

R460809770.0

cm51.7565psia100 33

2 c

P

T

TZ

VPV

sc

sc

SS

SS

sc =+

+

==

..............

(7)

Thetotalsolutiongasoilratioisthesumofallvolumesofgasreleasedineachstagedivided

theoilvolumeatstandardconditions

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STB

scf13.293

STB

scf614.5

cm0221.26

cm3192.104cm02.347cm4.9073

333

=++

=sSbR . ..... (8)

TheoildensityandAPIgravityare

3

lbm/ft501646.p,T scsco =

37585131

462

501646

5141..

.

.

.API =

Inthiscase,wehavelowersolutiongasoilratio,lowerBoSb,andhigherAPIgravitythaninthe

previouscase.Clearly,byaddingaseparationstagewewillhaveabetteroilqualityandlessgas

production.

Whathappensifwedonthaveaseparatorandjustproducedirectlytothetank?

Table 5Test Results With No Separator

p, psia T, F fo fg zo zg vo, cm vg, cm o, lb/ft g, lb/ft

1995.5 220 1.0000 0.0000 0.9958 0.8989 30.3952 0.0001 42.0204 5.4995

14.7 60 0.5495 0.4505 0.0148 0.9958 25.7392 1421.4707 46.5814 0.0550

STB

bbl18.1

cm25.7392

cm3952.303

3

==oSbB . ............................................................................. (9)

STB

scf310

STB

scf614.5

cm7392.25

cm4707.14213

3

==sSbR . ...................................................... (10)

3lbm/ft581446.p,T scsco =

05.585.131

4.62

5814.46

5.141API = . .............................................................................. (11)

Asexpected,wegotthehighestBoSbandthehighestsolutiongasoilratio.

Lab#5 PETE 310


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Onceyouhavereadthistutorialyouarereadytobeginwiththelab.

Lab # 5

Reservoir Fluid Report: Constant Composition

Expansion (CCE), Differential Liberation (DL) and

Separator Tests of a Live Oil Sample

ConductaReservoirFluidAnalysisforPETE310OilWell(GreatOilField).Comparetheresults

obtainedwiththereservoirfluidanalysisfromOilWell4fromyourtextbookanddiscussthe

resultsobtained. Thereservoirtemperatureis235oFandtheinitialreservoirpressureis4500

psia.

Table AComposition of Reservoir Fluid Sample

Super Aggie Well: PETE 310

Component Composition mol%

Methane 38.12

Ethane 10.75

Propane 6.84

n-Butane 4.89

iso-Butane 1.96

n-Pentane 1.27

iso-pentane 2.93n-Hexanes 1.96

C7+ 31.28

MwC7+ 236.00

SG C7+ 0.87

Procedure

Afterlisteningtherecordedtutorial studyingthebackgroundmaterialandtheexample

problemaccompanyingthislabdownloadthePVTSimulator.xlsfilefromourwebsiteandbegin

thelab.

SelecttheDataworksheet

Selectthecomponentsforthefluidsamplegiventoyou.

Enterthenumberofmolesofeachcomponentinthemixtureandthemolecularweight

fortheC7+fraction.

Lab#5 PETE 310


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Constant Composi tion Expansion Tests (CCE)

Thistestwillbeusedtodeterminethebubblepointpressureandisothermaloilcompressibilities

forallpressuresabovethebubblepointpressure.

SelecttheCCEworksheetandsetthetemperaturetothereservoirtemperature(235oF).

Typethepressurestepsfortheexperiment.Startat5,000psiapressure. Endthe

experimentat1,200psia.

CopyyouroutputtableintoanExcelfileforanalysisinyourreport.

Differential Liberation Tests (DL)

Thistestwillbeusedtodeterminetheoilandgasformationvolumefactorsandsolutiongasoil

ratios.

SelecttheDLworksheet andsetthetemperaturetothereservoirtemperature(235oF).

StarttheexperimentatthebubblepointpressureyouestimatedfromtheCCE

experiment.Selectpressurestepsof~400psia. Endtheexperimentat100psia.The

softwarewillautomaticallyaddastageat14.7psiaandreservoirtemperatureand

anotherat14.7psiaandstandardtemperature.

CopytheoutputintoanExcelfileforanalysis.

RepeattheDLexperiment,butnowchoosepressuredecrementsof100psia.

CopytheoutputtablestoanExcelfileforfutureanalysis.

Separator Tests

Theobjectiveoftheseparatortestsistofindaseparator(s)pressureandtemperaturesuchthat

theamountofstocktankliquidismaximized.Youwilltestthesystemwithasingleseparator

andnextwithtwoseparators.Besuretodevelopconclusionstoaddresstherelativeadvantages

/anddisadvantagesofeach.

One-Separator Test

SelecttheSeparatorTestworksheet andstartthetestatthebubblepointpressurethat

you

estimated

from

the

CCE

experiment

and

reservoir

temperature.

Enterthedesiredpressureandtemperatureoftheseparator.Anextrastageatstandard

conditionsisaddedautomatically.

CopytheoutputtableintoanExcelfileforfutureanalysis.

Thesearchforthebestcombinationofseparatorpressureandtemperatureshouldbedone

systematically.Youmayfinditconvenienttotestpressuresatincrementsof100psiaorsoand

Lab#5 PETE 310


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temperatureatincrementsof30to50oF.Pleasedocumentthestrategyfollowed tosearchfor

thebestpressureandtemperature.

Evaluatethepressureeffectforafixedseparatortemperatureandthetemperatureeffectfora

fixedseparatorpressure.Discusstheobservationsyoumake.

You willhavetoprovideplotssimilartoFig.10.5 fromMcCain.1 (similar,youdonotneedto

workwiththreedifferentaxes, twoyaxisatatimeisfine).

Two Separators

Selectthe

Separator

Test

worksheet.

StartthetestatthebubblepointpressurethatyouestimatedfromtheCCEexperiment

andreservoirtemperature.

Enterthepressureandtemperatureofeachseparatoryouwanttouse.Anextrastage

atstandardconditionswillbeaddedautomatically.

CopytheoutputtableintoanExcelfileforfutureanalysis.

Constraints

Separator1pressure

should

be

higher

than

Separator

2pressure.

Separator1temperatureshouldbehigherthanorequaltoSeparator2temperature,

andbothshouldbehigherthanorequaltothestandardtemperature(notlower).

Lab#5 PETE 310


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Required Reporting

AllrequiredPVTpropertieswillbeproperlydocumentedeitheringraphicalandtabularformor

inbothwhenspecificallyrequested.Makesuretodocumentallobservations,problems,

followedmethodology,etc.

Fromthe

CCE

experiment

plot

(Vt/Vb)

versus

pressure

and

verify

that

the

bubblepoint

pressureisobtainedfromtheintersectionoftwolines.

Evaluatetheoilcompressibilityforallpressuresabovethebubblepointdeterminedin

thepreviousstep.

Evaluatetheoilandgasformationvolumefactorsandthesolutiongasoilratioversus

pressureforthetwoDLexperimentsyouverunusingdifferentpressuredecrements

(100and400psia).Discussthedifferences(ifany)oftheseresults,includingthe

advantagesanddisadvantagesofeachprocedure.Rememberthatthevolumeofgas

reportedintheDLworksheetisatthepressureandtemperaturespecified,notat

standardconditions

PlotoilAPIgravity,solutiongasoilratioandformationvolumefactoratthe

bubblepoint fromtheseparatortestforalltherunsyoumadewithoneseparator.Label

yourgraphsproperly.

PlotoilAPIgravity,solutiongasoilratioandformationvolumefactoratthe

bubblepoint fromtheseparatortestforalltherunsyoumadewithtwoseparators.

Labelyourgraphsproperly.

Combinetheresultsobtainedfromyourbestcaseseparatorscenariowithyourresults

fromthe

best

DL

run

(p

=100

or

400

psia)

and

provide

atable

of

adjusted

reservoir

engineeringpropertiesBoandRsversuspressurefromallthesecombinedtests.Usethe

adjustedreservoirpropertiesindicatedintheclassnotes.

CalculateandplotBtDversuspressurefrom

Lab#5 PETE 310

) . ............................................................................... ( gsDsDboDtD BRRBB +=

Lab 5 Reservoir Fluid Studies

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