well testing lecture note m14sunday 11 jan 2014

7/25/2019 WELL TESTING Lecture Note M14Sunday 11 Jan 2014

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WELL TESTING Lecture NoteM-14 Sunday, 11 Jan 2015



• Introduction

• Well Testing Procedures and Hardware

• Examples of Typical Flow regimes

• Conclusions

Well Testing and Interpretation



Description of a Well Test

Drawdown :

Build-up :

Time, t

R a

t e ,

q

P r e s s u r e , p

t !

t "d

p "d

p !

p i

p# t$%&

drawdown 'uild(up

∆ ∆ p p t p t = − =( ) ( )0

∆ p p p t i= − ( )



Well Test Objectives

EXPLORATION WELL

APPRAISAL WELL

DE ELOP!ENT WELL




• EXPLORATION – Nat"re and rate of prod"ced fl"id – Initial press"re – Reservoir properties




– Reservoir properties• permeability• heterogeneity• reservoir boundaries

– Well productivity – luid properties !sampling"

APPRAISAL




– Reservoir properties• drainage mechanism !permanent

gauges"• communication bet#een #ells

– Well productivity – Average pressure

DE ELOP!ENT



Infor#ation obtained fro# Well Testing

– Reservoir responses• Reservoir in dynamic condition !$o# lines

are established"

• Large volume investigated !averaging" – Res"lts

Per#eabilit$ %&ori'ontal k and vertical k v(Reservoir &eterogeneities

– nat"ral fract"res) –

la$ering) – c&ange of c&aracteristics*Press"re %initial pi and average (+o"ndaries %distance and s&ape(

RESER OIR DES,RIPTION

p



Infor#ation obtained fro# Well Testing

• WELL %E&'RIPTION – Results

• Production potential – productivity inde( PI) – s*in +actor S

• Well geometry



Inverse problem : ) * I = +

Direct problem : I + = )

Interpretation !et&odolog$

I + )

input system output



Inp"t Data re-"ired for Well Test Anal$sis

• TE&T %ATA – lo# rate !se,uence o+ event" – -ottom hole pressure

• WELL %ATA – Wellbore radius r w and geometry

–%epths !+ormation) gauges"



Inp"t Data re-"ired for Well Test Anal$sis

RESER OIR AND .L/ID PARA!ETER – .or#ation t&ic0ness h %net( – Porosit$ – .or#ation vol"#e factor B –

Oil viscosit$ – ,o#pressibilit$ of oil co) 1ater cw and for#ation

c f ) 1ater sat"ration S w

( ) f wwwot c S c S cc ++−= 1



T$pes of Well Tests

– %ra#do#n test –

-uild.up test – In/ection test 0 +all.o1 test – Inter+erence test and pulse test – 2as #ell test

• lo# a+ter $o# test)• Isochronal test)• 3odi4ed isochronal test

PRO,ED/RE



T$pes of Well Tests

• 'O3PLETION

– Prod"ction test – Drill ste# test %DST(



Test Se-"ence %oil 1ell(

– 'lean.up period !drilling and completion $uids)no measurement"

– Initial shut.in !pressure gauge at depth) initialpressure p i "

– 5ariable rate !start o+ rate measurement"

– &tabili6ed rate !main $o#"

Time, t

Cleanup

Initialshut-in

Variablerate

Stabilizedrate

Build-up

Time, t

R a

t e ,

q

P r e s s u r e ,

p

Cleanup

Initialshut-in

Variablerate

Stabilizedrate

Build-up



S"rface E-"ip#ent

• LOW 8EA%7 fowin , !i""in , wire"ine• '8O9E 3ANI OL%7 #o$iti%e &

ad'u$ta("e

• 8EATER7 )ydrate$, )i ) %i$co$ity• &EPARATOR7 *eterin o+ t)ree #)a$e$• TAN97 oi" rate

• -:RNER



S"rface E-"ip#ent

S/R.A,E SET/P

urner

urner

Heater

+eparator

+urge

tan-

Air

compressor

Water

pump

Rig !

pump

.as

)ilWater

C/o-emaniflod

Flow/ead

"rans#er pump

$ilmani#old

%as

mani#old



Test Separator

• RATE 3EA&:RE3ENT – i" and water #o$iti%e di$#"ace*ent – Ga$ ori.ce *eter

T2REE P2ASES3 oil, water and gas

&##luent

Water $il

%as

&##luent

Water $ilWater $il

%as



Do1n 2ole E-"ip#ent

• PRE&&:RE 2A:2E&7 *e*ory or $ur+aceread out

• %OWN 8OLE 5AL5E7 /ST, $a*#"in

• -OTTO3 8OLE &A3PLER7 T ana"y$i$

• R T) 3%T7 initia" #re$$ure, radient &contact$, #er*ea(i"ity



Safet$

• E;:IP3ENT7 #re$$ure, te*#erature, $our a$

• PRO'E%:RE7 #re$$ure te$t, e*er ency $)ut-

down, day ni )t, $a+e area• EN5IRON3ENT7 (urnin , oi" dro# out



Analysis of Simple Well Tests

• Objectives of well tests

• Types of well tests

• Basic a alysis of:

-- Pres su re d r aw dow t e s t s

- - P re ssu re bu i ld -up t e s t s

- - W el l i t e r fe re ce tes t s



Types of Well Tests

Produci g wells jectiowells

Pressure drawdown Pressure fall off 0ultiple rate 0ultiple ratePressure 'uild(up In1ecti2ityWell interference Well interference"rill stemReser2oir limit



Objectives of Well Tests• .at/er transient fluid flow and pressure data in

one or more wells simultaneously• 3nalysis aim at understanding and quantifying

reser2oir and aquifer 'e/a2ior • Pro2ide -nowledge a'out reser2oir si4e and

continuity

•

Pro2ide estimates of in(situ properties suc/ asporosity, permea'ility, transmissi'ility,producti2ity, in1ecti2ity and formation damage nearwell'ores



Pressure !rawdown Tests




Examplet) 2o"rs 4 4*5 6*4 6*7 8 5 9 : 6; 69 ;5 85 54 94 :5

P 1f ) psig ;587 ;<=: ;<;< ;87; ;85; ;88; ;865 ;868 ;864 ;849 ;84< ;84; ;844 ;;:7 ;;:=



Pressure !rawdown TestsExample, continued

well testing lecture note m14sunday 11 jan 2014

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