Production Logging- Field Session

8/12/2019 Production Logging- Field Session

1/75

I.IHAT

IS PRODUCTION LOGGING ?

The

primary

objective

of Production

Loggjng

is the

analyss

of fl

ui

d

movement

systems, defi ni ng

'system'

as some type of

flow

regime

in

a well.

Production

Logging

js

a

method

that

measures

and

records

the

flow

of fluid, ol the effects of the flow

of fluid,

past

the

measuri ng i nstruments

pl

aced

at

varyi

ng

depths

i n

a

produc

ng

or

i

njecti

on wel I

.

Stated simply, a Producti

on Log

I

ocates

the

source of entry

or exit

of the flujd,

jdentfjes

the composition

of the fluid,

nd

quantifies

the

fluid

by

measuring

its rate.

The mai n dj fference

between

Producti on Logs and other

types

of

1ogs, such

as open-hole

or

cased-hole

1ogs,

is

that

Production

Logs

are run whjle

the well

is

under

its

dynamic or

'actjve'

condition, while the other logs

measure a

'fixed'

set of

parameters

usuay

under

statjc condjtjons.

Some of the

quest.i

ons

wh

j

ch

may be

answered

by Product

j

on

Loggng

are:

1.

t^lhat is the flow

profile?

2. trlhat

j

s

the

j

nject'i

on

profj

I

e?

3. Are

al

I

perforat'i

ons

producing

as

p

anned?

4.

Is

undesjred

water or

gas

coming from

a

s'i

ngle

zone?

If

So,

which

zone?

5. Did the

acidizing

or frac

job

perform

as

panned?

6.

Are

there casng,

tubing,

or

packer

leaks?

7 . Are zones effect

vel

y

i

sol

ated?

8. Are

thief zones

present?

9. Is

there

corrosion damage?


2/75

10. Are

there

zones that need

to

be

stmulated?

11.

Where

have

the st imulation

fluids

gone?

12. Is the reservojr

depletion

takjng

place

as

i ntended?

Production

Logging

can evaluate

the

behavior

of wells

and

reservoirs

producing

under

stabilized condjtjons.

It

is

often

vi tal ly

mportant

to study

the

performance

of the

j

ni

ti

al

completjon to assure

that

the

mechanical

system is

performing

as

pl

anned.

Subsequent

changes

in the

production/injecton

rates

of

a

gi

ven

wel

I

have

a

s igni

f

i

cant

beari

ng on

the

perf

ormance

of

both

wel I and

reservojr. These

changes

can seriousy affect

maxjmum

economic recovery of hydrocarbons

from the reservojr.

Varyng

permeabil

ities

jn

formations within a

reservo i r

can

lead

to select i ve

drainage

which may leave behind

oil thought

to

have been

produced.

Channels in cement

can

cause unsuspected

dra i

nage

of reserves

set aside for future

productjon.

Channels

can

al so I ead to thi evi

ng

of

producti

on

i

nto adiacent

f ormati

ons.

Production

Loggjng can verify the status

of

a

reserve,

and

keep

current the

p l

ans

f or opt imum reservoi r

dep et

j

on.

D agnosi s before a workover

wi

th Producti

on Loggi ng

can

assure optimum app l

cati on of

remedi

al

procedures.

Repai

rs

are

often

s

i

mp1 fi

ed

and

I

ess

harmful

to the wel I or

reservoi

r

when

the

problems

are

understood and

well defined.

Quite

often

some

types of

remed

j

al

work can be

performed

most economi

cai

I

y

by

using

ony wjrel

jne

services.

2


3/75


4/75

PRESSURE

CONTROL

In

order to survey

produci

ng and

i n

jecti

ng

wel I s

i

n

thei

r

dynamjc

state, it

js

necessary

to

enter

the well

while

it

is

under

pressure. In

these operations

where

high

pressure exsts,

reducti

on of wel I

head

pressure

to

a

mi

n imum

i

s essent

j

al

to

reduce

the

frictjon of the

wireljne

to

a minimum,

and

to effect a

complete

seal between

the wjreline and

the surround i ng

atmosphere.

Mai

ntenance

of

a

compl ete

seal

i

s

of

pri

me

importance

where the

operati on be

j

ng

perf

ormed w i

I I not

tol

erate

the I oss

of

fl

ui

d,

such

as a

gas

wel I where

venti

ng

to the

atmosphere

woul

d

present

a

safety

hazard,

and

al

so

woul

d

I

et

i ce

form

which

would

freeze-up

the

wirel ine.

The equ

pment

necessary

to

perf

orm

thi

s

operat i

on

i

s

collectivey

called

a

lubricator. A

w ireline

lubricator

system

cons i sts of an

appropri

ate

f

tti

ng

to

f

I

ange

up

to

the wel

I head,

a

wi rel i ne

bl owout

preventer,

a

ri

ser

p

i

pe,

a

control

head

wj

th

a

pressuri zed grease

system,

and

a

hydraul

j

c

packi

ng

g1

and.

In operat on,

the

bl owout

preventer

i s

attached

to the

wellhead

wjth enough

riser

pipe

to

accommodate

the ogging

i

nstruments.

A control

head i

s

attached

to the

top

of the ri

ser

p

j

pe

wh

jch

conta

jns

the well

f

luids

v ,hile allowing

the

instruments

to

be

moved

in

and

out of the

well.

The

heart

of

the

I

ubri

cator

system

i

s the control head.

The

control head

consj sts of two

or

more

fl ow-tube assembl

i

es

put

together i n

seri es,

and

the hydraul

j

c

packi

ng

gl

and.

A

fl

ow-

tube is

a

tube

which

fits t ightly

on

the wireline

and

is

pressure

4


5/75

sealed

on

both ends. A

sujtable

grease

js

pumped

jn

between

the

flow-tube

assembljes

at a

pressure

of 500

to

1000

PSI

greater

than

the

exi

st

ng

wel I head

pressure.

The

fl

ow

tubes

create

pressure

drops

across

the

wirel

ine,

wh'ile

the

grease

creates

an

effective

seal impervious

to the

passage

of

the

well fluids.

The

hydraulic

packing

gland

js

a

rubber

seal whjch is

attached

around

the wi rel

i ne

at

the

top of

the control head.

The

rubber

can be

hydraul

jca'l

1y

compressed

ejther

partial

ly

or completely

to

form a

part

a

or

compl ete

seal

around

the wi

rel'i ne.

An

exhaust

hose i s

normal

1

y

attached

between

the

packoff

gl

and

and

the

uppermost

fl ow

tube

assembly.

The

packoff

gl

and

serves

two

important

purposes.

It

al

I

ows

the

I

j

ne

to

be

enti rel

y

packed

off

i f the

grease

seal is Iost, oF

the too'l

s

have

to

be stopped

for

a Iength

of

t'ime. And second'ly, i

f the

rubber

seal

'i

s

iust

parti

al

y

compressed,

i t stri

ps

the

grease

of

f

of the l'ine and f

orces i

t

to

go

out

of the exhaust

hose

where

it can be

properly

dsposed

of

.

The

w'i

rel'ine

blowout

preventeli

s

jdent

jcal in

operation

to

a

gate-type

bl

owout

preventer

found

on rgs.

It consj

sts of two

rams opposite

one another

whjch

may be mechanically

closed

aganst

the wireline.

The

ends of the

rams

have rubber seals

which are

compressed

against

each other with

the

wirel

ine

posit'ioned

jn

the

mjddle.

This

procedure

forms

a

I00

effective

seal

around

the wireline.

The

primary purpose

of a

blowout

preventer

i s i ts use as a

safety

devj

ce

whj ch al

I

ows

the

wel I

head

connect

j

on

to

be seal ed

of f wi th wi rel

'i

ne

remai n i ng i n

the

well.

5


6/75


7/75

-

EXHA

LINE

FLOW TUBE

ASSEMBLIES

HYDNAULIC

PACKING

GLAND

SEAL

INLET

INSTRUMENTS

RISER

TUSE

ALOWOUT

PREVENTER

+WELLHEAD

PRESSURE

CONTROL EQUIPMENT

vTRELTNE

LuaarcATo+

7,


8/75

DEPTH

CONTROL

The

most

'important

aspect

of

any

type

of

wi rel'i ne

operati on

is

prec'i

se depth

control. Accurate

depth resolution

'i

s

essential

to all

the

phases

of well loggng.

0ne

must

be

able

to

correlate

the

'

oggi ng

j

nstruments

to the

perf

orati

ons

i

n the wel I

whi ch

are

in turn

correlated

to

the vary'ing

sands

jn

the

reservo'i

r.

l.lhen a well s

initially

dr11ed,

a

suite of open-hole

ogs

'i

s

usual

I

y

run.

0n

most

of

these 1ogs,

a Gamma

Ray

Log

i

s

usually run in

conjunction

with the

primary

log.

The

G-R

Log

measures the naturally-occurring

radioactivty

of formations

adjacent

to the

bore

hol

e. In

sedimentary

format

ons,

the

G-R

normaly indicates the shale

content of the format'i

on since

radi oacti ve el ements tend

to

concentrate

'i

n

shal e

and

cl

ay.

Although

radjoactive

salts

are

continuay

deposited

on

or washed

av',ay

f

rom

the wel I

bore

duri

ng i ts I f e, the

general

shal

e

characteri

st'i cs remai n

rel

at

ve'ly unchanged and are

easi

y

i

denti

fi ed

throughout

the

I

j

fe of the

wel

I

.

Because

the

formatjon

does

not

physica1y

move, the G-R Log

provides

an

excel I

ent

depth reference.

The first G-R

Log

run

js

referenced to

a

point

0n

surface

usual 1y

the

Kel ly-Bushi

ng wh'i

ch

i

s zero,

or

the start

of the

I

og.

Al

I subsequent I ogs run

are

then

referenced

to

th i s

orignal G-R Log.

After

cas'i

ng

is set

n

a well

and

cemented in

place,

a

Cement-Bond

Log

is usually run. A G-R

Log

is

run in

conjunctjon

w'i th the CBL

and

correlated

to the original

open-hole

G-R Log.

I


9/75

The CBL

also

records

the

casing collars

on depth

wjth respect

to

the

G-R

Log.

These

cas ng-col I

ars

provide

another

permanent,

non

-mov

ng,

reference

po

i nt . When

the

wel I

j

s

perforated,

a

collar locator is run in

conjunct i on

with the

perforating

guns.

A Collar Log

is

then

run

pror

to

perforating,

which

assures

that

the

perforatjons

wjll

be

on

depth

with

respect

to

the

open-hole

G-R Log,

which

is

usually

the

log

from which

the

perforated

i

nterval

s

are

p i

cked

.

When

Product ion Logs

are

run in cased hole, the

casing-

col

I

ars are

used f

or the depth

ref

erence.

The Col I ar- Log

i

s run

in

conjunction

wjth

the

different

Production

Logs

ye1dng

a

real

time

depth

control

wjth

each

log.

Usjng

the casing collars as a

permanent

reference,

one

i

s

abl

e to

prec i

sely

I ocate retri evabl e

compl

etj on equi

pment

such

as

packers,

pl

ugs,

fl ow-chokes, etc.

[^Jhen

an

injection

well is completed with

a

single-string-

multiple-packer type

i

nstallation,

it

s

not

possible

to

log the

casing

collars. In this

jnstance,

the injection

equipment

js

ogged with a

G-R

Tubing

Collar

Locator

pri

or to

sett i

ng

the

packers.

This

G-R Log is

then correlated

to the

original

open

hole G-R

Log.

The injection

equ i

pment

can then

be

adjusted

up

or

down

to

place

the

packers

jn

their

appropriate

postions.

Usng

a G-R Log enables one

to

place

the

injection

equpment

in the

wel I bore wi th

an

accuracy of approximately

one

foot. After

the

packers

are set,

we

are

I

eft

wi

th

a

permanent

record of

the

posi

ti on of

the injection equipment

wjth

respect

to the

perforatj

ons

i

n the

wel I

bore.

9


10/75

After

the

well has been

placed

on injectjon and an

injectjon

profile

needs to be run,

a

Collar

Log

js

run

in

the tubing

strng

to correl ate the

I

oggi ng

i

nstruments

to

the

wel

I

bore. Thus, al I

flujd losses can

be

accuratey assigned

to

individual

perforati

ons, or zones.

Although

it is surprisingly

simple, the collar-locator

tool

js

probaby

the single

most

valuable tool

jn

the Productjon

Loggi

ng

stri ng. There

are

two

basi

c

types

of Col I

ar

Locators:

1)

Logging

Collar

Locators;

and 2)

Shootng Collar Locators.

The di fference between

the two i s that the

Shoot

ng

Col

I

ar

Locator

js

a

passive

device

and

does

not

need

power

supplied

from

surface to operate. Power i

s

i ntenti

onal ly

kept

off of the

wjreline

during the logging

procedures

to

prevent

the

accidental/premature fjrjng

of the

perforating guns.

A Loggng

Col

I

ar

Locator

runs

para

el wi th

whatever

I

oggi

ng i

nstrument

i

s

current ly

bei

ng

used

and derives i ts

pou,er

f rom the

power

suppl

i

ed

to

the

I

ogg

ng

j

nstrument.

A

Collar

Locator

cons i sts of two cyindrical magnets

separated by

a

coi

l

of very f

ne wi

re v /ound

on

a

spool .

The

magnets

radiate

flux l inei

in

all

directons. tJhen these flux

I i nes

are

cut by

a

ferrous materj al

such

as tubi ng,

col 1

ars,

packers,

etc.,

a

voltage

is induced

across

the

co i l. Appropriate

circutry filters this

voltage

and

conditions

it for surface

recording. A separate circuit at

the

surface

selectvely

ampl

i

f i es any chanq

j

ng

vol

tage

I evel

and

causes the recorder to

respond

to

d i

fferences in

magnetic

mass.

This

response

enables

10


11/75

the

Col I ar

Locator

to

see

only

the col ars,

packers,

mandre l

s,

shoes,

etc.

,

rd

not

conti nuous

tubi ng or casi

ng.

lirlj

th

the

ga i

n

propery

adjusted,

a

Collar

Locator

is

sometimes

helpful

in

locating

holes

and

splits or

other

irregularities in

the

tubing

or cas i

ng.

MAGNET

PICKUP

COIL

IANET

LAR

COLLAR

-

LOCATON

CONFIGURATION

COLLAR

NECORDE

ON

SURFACE.

N

.9

.9

N

11


12/75

'|

I

I

I

a

a

(

8000

stoo

60

6to

coLLAR

LoG

lN

7 23tb.

cs

COLLAR

LOG IN SELECTIVE

INJECTION

EAUIPMENT

FIELD

EXAMPLES

OF

COLLAR

LOGS

l2

t

\

t

_>

I

I

I

t

t

T

,

-

-

t

t


13/75

TEI,IPERATU

E SURVEYS

A Temperature

Survey

i s the

ol

dest

f orm

of

Product i

on

Logging

i

n

existence

today.

There have

been more

techn i cal

papers

written

about

it,

more

loggng

techniques

impemented,

more

tool

s deve l oped, rd

probabl

y

more

ogs

run

than

any

other

type of

Product i

on

Log.

And

Yet,

because

of i ts

i nherent

compl

exi

ty,

t

remai

ns

the I

east

understood

of

al

I

Producti

on

Log s

.

A

Temperature Survey

measures

the effects

that

produced

or

injected

fluids

have

on

the

geothermal

gradient

of

the

wellbore.

Temperature

oggi ng i

s

based on the

assumpti

on

that

the

formati on

surround i

ng

a

wel I

i

s a

1arge,

thermal

ly

stabl

e mass.

Natural

geothermal

gradjents

are

caused

by

the

continuous

flow

of

heat

outward and

upward

from

the

interior

of

the

earth.

Ths

flow

of

heat wi

I I

usual

ly

reach

some

state

of equi I

j

brj

um,

dependi

ng upon

the thermal

conducti

vi

ti

es of the

formati

ons and the

mean

surface

temperature.

t lhen

fIu ids

are

produced

from

or

iniected

into

the

formatj

ons,

the natural

,

or

normal

,

geothermal

gradi

ent

j

s

changed

because

of

the

dj

fferences

i n temperature

between

the

fl uids and

the

surroundi ng

wel I

bore. These

di fferences

between

the

geothermal

gradj

ent

of a

stabi

I

i

zed,

or

normal

we

,.

and

the

gradj

ent when

t

normal

condj

tj ons

have

been

changed,

are

of

ten

used

to

hel

p

i

nterpret

d i

f

f

erent

aspects

of a

wel

I s

beh av

i

or.

To

better

understand

the effects

of

product i

on on

the

geothermal

gradi

ent, both

extremes

must

be

consi

dered.

0ur

13


14/75

hypotheti

cal wel I

has

one i

nterval

from

whi

ch i

t

produces.

0ne

extreme

s

zero

fl ui

d

fl ow

from the

produci

ng

i nterval

.

Thi

s

extreme

woul

d

render a

temperature

I

og

wh

i

ch

i

s the

same

as the

normal geothermal

gradient.

The

other

extreme which can

only

be

theoretca1

is

jnfjnjte

flow.

If our well

were

to

produce

at

an

nfinite

rate

the

temperature

of

the

fl uid

when it

reached

the

surface

would

be

the

same

as

the

temperature

of the

fluid

when

it

entered

the wel

I bore.

Thi

s temperature

survey

woul

d

be a

straight

vertjc.al

line

from

surface

to the

bottom

of

the

producing

interval.

Therefore

any

well

condition

between

zero

and

infinity

jn

our hypothetical

we1

would

produce

a

temperature

survey

whose

grad

i

ent

s

ope

woul

d

be

between

the

two

extrettles.

FLOWNA

VELL

INFINITE

FLOW

SURFACE

t

I

t

I

1

t

I

I

I

I

I

\

I

t

I

t

I

\

t

t

PRODUCING

NTENVAL

TEuIPERATURE

INCREASES

ZERO

AND

INFINITE

FLOW

TO

./

14


15/75

SHUT-

IN TEMPERATURE

SURVEYS

A

very

important

aspect

of

temperature

I ogg

ng

j

s

the

shut-

in

temperature

survey.

When

a well

is

flow i ng,

the wellbore

temperature

gradjent

is

changed

by

the

f l

ow i

ng

fluids. If

a

well

is shut-jn

and

the

fluid

held

static,

the

wellbore

temperature

is

immediately

affected

by the

formatjon

temperature.

The

wel I

bore

temperatures

then

beg in

to

stabi

I

j

ze and

return

to

thei r

normal

grad ient

temperatures

.

SURFACE

\

PRODUCING

TEMPERATURE

SURVEY

SURVil.LOG

NO.

I

\

\

SHUT-IN

SURVEY.LOG

NO.

2

PRODUCING

INTERVAL

TD

\

NORMAL

GEOTHERAL

GRADIENT

TEITTPERATURE

//NCREASES.-\.

SHUT-IN

TEMPERATURE

SURVEY

In

our

has

built

hypothet

j

cal wel

I

at

up

from

productj

on

the

perf

orated

nterva l

,

The

format i

on

above

heat

the

15


16/75

perforations

has bujlt

up

because

the heat

carried

by

the flow

in

the

pipe

has

been

transferred

into

the

formatjon.

trlhen

the

welI

i

s

shut- i

n,

this

heat

js

carried away

from

the

wellbore

as

jt

returns to

gradi

ent. The rate of

gradj

ent

recovery,

or

stab i

I i

zati

on, i

s

dependent

on many

factors

such

as

producti

on

rates,

the amount

of

time the

wel I

has

produced,

d

the

heat

transfer abjljties

of

the rock

conducting

the

heat

away,

etc.

Al so, the

temperature

of the fl

uj

ds

as

they enter

the

wel I bore

i s

qui

te often

h

i

gher

than

that of the

stabj I

j

zed

gradj

ent.

Thj s

difference

in temperature

js

due

to the fact

that

the

fluids

origj

nate

j

n

areas

where

the

gradi

ent

has not

been

di sturbed.

Two

exampl

es

of

th i s temperature

di f f

erence

may

be

f ound

i n:

1.)

wel

I s

produci

ng

from fractured

reservoi

rs where

produced

fl

uids

have

mi

grated

from

deeper,

therefore

hotter

zones through

both

verti

cal

and

horj

zontal fractures,

2.) wel

I s

produci

ng

from

an

j

ncl i

ned

reservo

i r where

fl u

i

ds

tend

to travel upward

as

they

approach

the

wel I

bore.

As

js

evjdenced,

the

longer

the

well

js

left

shut

it, the

cl

oser

the temperature

survey

i s to

the

normal

gradi

ent.

At

the

producing

jnterval

the hot

iquids

jn

the

formatjon are

slowng

the

recovery

to

the

normal

grad

j

ent.

The reduced

recovery

rate

is

appearjng

as

a

heating anomaly at

the

production

zone.

COLD

FLUID INJECTION

fl u i ds downhol

e

from

surface

to

the depth

of

zero

fl

ow,

of

Injectng

normal

gradi

ent

wi

I

I di

sturb

16

no

fluid loss.

the

The


17/75

tenperature

gradi

ent and

the

degree

of

separati

on from

the

normal

gradj

ent are

determj

ned

by

the temperature

of the

i niected

flu ids,

the rate

of

iniect i

on,

the

length

of

time

of

jniecton,

and

many

other

varj

abl es.

In our

hypothetj

cal wel

I uJe

can

see

that

whi

I e fl

uids

are

bei ng

j

njected,

the

wel

I bore

above

the

perforati

ons has

been

cooled

by

the injectjon

fluds.

Thjs

cooing has

been

caused

by

the increased

rate

of heat

transfer from

the

formation

into

the

cooler

wellbore.

Below

the injection

interval,

jn

the

area

of

no

fluid

loss,

the

temperature

curve

i

s that

of

the normal

gradent.

When

the well

js

shut

jn

and

the flu id

held

statc,

the

shut-in

gradients

start to

stabjl

jze

and

return

to

the normal

gradjent.

SURHICE

\

\

\

I

9HUT-IN

\

TEMPERATURE

SURVEY.LOG

NO.

I

\

\

aHUT4N

TEUP.

sunuEY

\

SURUEY-LOO

to.

2

IwtECTlOt

INTERUAL

,rry

OEOTHERMAL

GRADIENT

\

\

TD

TEHPERATURE

INCREASES -_>

COLD

FLUID

INJECTION

t7


18/75

As

j

n

the case

of

the

produci

ng wel

l

,

the i

niecti

on

'i

nterval

remai ns

cool

er

and

sl ower

to

recover

to

the normal

grad

i ent

because

of

the

colder

fluids

stored in

the

formation.

The

mai

n

app

i

cati

on

for

temperature surveys

i

n

i

niecti

on

wells

js

to identify

the zones

where

'i

nject'i

on has

taken

place.

Because

there are

so

many

uncontrol

I abl

e vari abl

es i n

a water

injection

system,

(e.9.,

flujd

characteristcs,

jniect'i

on rates,

thermal

properti

es of

formati

on

I

j

tho ogy,

thermal

propertj

es of

tubing,

packers,

cas'ing

cement,

etc.,

length

of shut-'in

times,

total

volumes

of

jniected

fluids at

varying

temperatures,

and

probably

a

host

of

othe s,)

OUANTITATIVE

IN

TFRPRFTATTON

OF

TN.IFTTTNN

T

EM

DtrD TTIIDF CIIDVFV TC N

OTP

D^rTTr^l

Al

so,

h

inject'i

on

well

js

usually

part

of

a

very large

flood

pr0gram.

There

are

arge

quantities

of fl uid

moving

through

the

reservo'ir

rock

from

several

di fferent

wel I s at

several

di fferent

pressures

and

temperatures.

0ften

these

wel

I

s i

nteract

and

i nfl uence

each

other,

making

a

quantitatjve

interpretat'ion'impossible.

CHANNELING

Quite

often in an

iniection

we'l

l, fluids

w'i ll

leave

the

wel

I

bore

from

the

perforated

i nterval

and

channel

ej ther

up

or

down

to some

other

po

nt i n

the wel I

bore.

Channel

j

ng

can

be

caused

by

poor

cement

bond,

fractures

cl

ose

to the

wel

1

bore,

corroded

cas'i ng,

etc. In a

produc'i

ng

well, unwanted

flu'ids

can

channel

from zones

other

than the

producing

zone

to the

producing

18


19/75

i

nterval .

Temperature

surveys

can be used

qu

te read

1y

to

locate

the

channe'l

ing.

In

the fol 1

ow ng

examp

e, the

i njecti

on

temperature

survey

does

not

return

to

the

normal

gradient

until

some

point

below

the

injectjon

jnterval.

This reaction

indicates

that

some

portions

of the i

n

ject'i

on f

I

u'ids

are

channel i ng

down

the wel I

bore to

a

di

f f erent

zone. The

shut-'in

surveys reveal

the

same

cool

i

ng

anomaly

across the

i nterval

where

the

njected

fl

ui

ds

are

stored.

SURFACE

t

\

t

SHUT.ilV

TELIPERATURE

\

SURUEY-

LOG

NO.

I

\

\

\

SHUT-IN

IHJECTION

INTERUAL

\

SUNVEY-LOG

NO.

2

l--

- f

ZONE:

\

\

\

\

\

\

NORTAL

I

AEOTHERUAL

GRADIENT

TAKI,IG FLUID

NJECTNG

TETAPERATURE

SURVEY

TD

TEnPERATURE

ilCREASES--L.

INJECTION

FLUID

CHANNELING DOWN

lllhen f I

uids

channel

up,

it

'i

s

necessary

to run

one or more

shut in temperature surveys

to identify

the

zone

takjng

the

fluid

19


20/75

because

the temperature

of the i ni

ected

fl u

j

ds wi I I mas

k any

anoma'ly

which

might

be

present.

0nce

the

wel I

js

shut-'i

n, it

is

evident

that the

anomaly

js.recovering

to

gradient

at a

reduced

rate.

Therefore,

jt

can be

concluded

that a portion of

the

injected

fl

uids are

exitng

the

perforated

interval and

channel

ing up.

SURFACE

I

\

\

\

9HUT-tw

\

\

SURVEY-LO

NO.

t

\

\

EONE/

\

\

TAKING

FLUIP

\

\

9HUT-1il

TET'PERATUPE

\

SURVEY- LOG

NO.

2

t&tEcTtot

NTERUAL

\

\

\

\

INUIECTING

TETIPERATURE

sunvEY

\

\

NORMAL

\

--GEOTHERbIAL

(

aRADnENT

\

n

\

TET'PERATURE

IICREASES

E.

INJECTION

FLUID

CHANNELING

UP

GAS

PRODUCING

Free

gas

producti

on

j

nto a

wel

I

temperature

anomal

y.

[,{hen

gas

j

n

a

w'i

ll result in a

definite

to a

lower

20

format

i on moves


21/75

pressure, it

undergoes

a

temperature-volume

change.

Th i

s

change

commony

occurs

jn

a

well where

there

are

perforat i

ons

in

a

cased

hole,

and

at

the

producing

formation

face

in

an

uncased

hole.

As

the

gas

enters

the

wellbore,

the

pressure

js

suddenly

dropped,

causing

an

increase

in vo l ume,

which

consequent ly

causes

a

drop

j

n

temperature.

The effect

that the

temperature

tool measures

j

s

a

cool

i

ng of the

gas

assoc i

ated

wi

th

j

ts expans

i on.

0ur f i rst

examp l

e shows a

gas

entry

i nto

the

wel I bore.

As

the

gas

leaves

the

pore

spaces

i

n the

formation

and

enters the

wel

I

bore,

i

t

expands,

creat

ng a

cool

i ng

ef f ect at

the

po i

nt

of

entry

and

above.

\

\

t

\

PRODUCING

SURVEY

NORMAL

\

GRADIENT

\

\

PRODUCIN6

NTERUAL

\

\

TD

T,EI|IPERATURE

INCREASES ->

GAS

ENTNY

2T


22/75

The

gas

i s then warmed,

crosses

the

geothermal

gradi

ent

I

i

ne, nd

cont'inues

upho

e

paral

l

el to

the normal

grad'i

ent,

but

at a

higher

temperature. The

temperature

change

at

such

an

entry

wjll

be

affected

by

the

amount

of

gS,

the

pressure

drop,

and

the

movement

of

other

fluids by

the

entry.

0ur second exampl e shows a

producj

ng

wel I wj

th

gas

bei

ng

produced

wi

th the

o

j

I .

The

produc'i

ng

temperature

I og

shows

normal

heating

due

to oil

production.

There are,

hotvever,

sl ight

cool i ng anomal i

es

across

the

produci

ng i nterval

caused

by

the

gas

enteri

ng the

wel I

bore

w'i

th the

o'i

I

.

l'lj

th the

wel

I shut- i n,

gradi

ent

recovery

temperature 1

ogs i ndi

cate secti

ons of the

perforat

j

on s cool

ng

due to the

gas product

i on

.

SURFACE

PRODUCING

TEMPERATURE

SURVET

gHUT.N

NORTIAL

GEOTHENMAL

6RAOEilT

/ ,

SURUEY.LOG

NO. I

SHUT.IN

TURE

SURVEY-LOG

NO.

2

TD

./

TEMPERATURE

INCREASES

OIL

WITH

GAS

ENTRY

?.2


23/75

SURFACE

I

t

I

I

I

I

SHUT.N

TEMPERATURE

TOP

OF

t

t

I

I

APPROX.

CEMENT

coLunU

12

HOURS

AFTER

CEIENT

IN

PLACE

t

t

t

t

t

NORMAL

I

GEOTHERMAL

GRAOENT

t

t

t

I

I

I

I

t

t

t

t

t

TD

TEnPERATURE

mCEASES

------\

LOCATING

TOP

OF CEMENT

LOCATING

CE].iIENT

TOPS

0ne of the

ol

dest

uses

of temperature

surveys

i

s to I ocate

the

cement

top

af

ter

a

stri

ng

of

cas i ng

has been

cemented i n

pl

ace.

As

the

cement sets,

oF

cures,

j

t

undergoes

an

exotherm ic

reaction

and

gjves

off

heat

to the surrounding

wellbore. If a

temperature

survey is run

while

this reactjon is

taking

place,

or

i

f the

cement

has

been

over-pl

aced,

the

survey

wi

I

I

show

h

i

gher

temperatures

at

the

depths corresponding

to the

cement column.

Thjs survey should

be run wjthin

24

hours after

the cement

job

to

obtajn

optimum

results.

23


24/75

SUNFACE

\

\

\

t

t

I

I

BASE

t

TETPENATURE

SURUEY

t

1

t

I

I

I

AFTER FRAC

I

\

I

I

TEiIPERATURE

SURVEY

NORMAL

I

ZONE

ACCEPTING

FRAC FLUID

GEO

t

GRADIENT

I

I

I

t

I

t

I

t

rD/

TURE

INCREASES

FNAC EVALUATION

FRAC

(AFTER

ACrp) EVALUATI0N

Temperature

I

ogs can

be

used

to

eval

uate

frac

iobs

i

n

much

the

same

way

as

they are

used

on water

j

n

ject i

on

wel

l

s, di f f eri ng

only

jn

the

fact

that

a

frac

usually

has hgh injection

rates

and

comparative ly

short

injection time.

A base temperature

survey i s

run

pr

or

to

the frac

to

gi

ve

a

normal

grad

j

ent

because

the

geothermal

grad

i ent

probabl

y

has

been

altered

by

production

or injection.

Interpretatjon

of

the

frac

eval

uati

on temperature log

depends on

a

measurable

dj fference

between

the

i

njected frac fl

uid

temperature

and the

ambi

ent temperature of

the

formati

on

pri

or

to

the frac.

24


25/75

If

the

frac

fl

ui

d i

s

hotter

than

the

formati

on temperature,

the entl

re wel

I

bore

wi I I have been

heated

above

normal

formati

on

temperatures. Also,

the

jntervals

that received

the

frac fluids

will exhibit a

slorder

recovery

rate in

returning

to

the

original

formation

temperature.

As

with

any

fl ud

iniection

system,

the

rate

of

recovery

js

dependent

upon

the

amount

of

frac

fluids

i

nvol

ved and

the

temperature

di

fferences

encountered.

lllhen

acjd

is

injected

into

a

well

for

stimulation

or other

purposes,

temperature

surveys

can

be used

to

identify

the

zones

takjng the

fluid, in much

the

same manner as

the

frac evaluaton

applicatjon.

There

may

be

minerals

present

wjthin the reservo in,

such as

carbonates,

whjch

have an

exothermal

reaction

wjth acd

which

will create

a measurable

increase in

temperature.

The

presence

of m inera l

s

ntroduces

an

add itional

f actor along

with

the

normal formati

on

temperature and

usual

1

y

cool er treatment

fl i

ds, thus maki ng

i

t even

more

crj

ti

cal to have a

base, or

reference

survey pri

or to

the

aci

d

treatment.


26/75

SURFACE

I

=

I

I

DIFFERENTIAL

I

TURE

I

SURUEY

\

AASOLUTE

I

\

SURVEY

\

\

\

t

I

I

I

ARGE SPONSE

I

STIIALL

STIALL

TETIPERATURE

ANOTIALIES

t

SLOPE

CHANGES

I

t

t

\

I

\

\

NORIAL

GEOTHERTAL

GRADIENT

I

t

^/

D

I

\

TEUPERATURE

INCREAS

DIFFERENTIAL

TEMPERATURE

SURVEY

I

DI FFERENTIAL

TEMPERATURE

0ne

type of survey

presentati

on

whi

ch i s

qu ite popu

ar

i n

many

areas

j

s

the

Di

fferentj

al

Temperature

Curve.

A

di

fferenti

al

temperature

survey measures

the

rate

of change of the

gradj

ent

curve. This

survey

allows

identification

or

amplfjcat ion

of

small anomal

jes

which

may not

appear

sgnjfjcant

on the

absolute

temperature

curve. D i

fferentj

al

temperature surveys

are normal ly

run when I

arge

s1 ope

changes

are not anti

ci

pated.

The

Di

fferent

i

al

Temperature

Curve

j

s

derj

ved

el

ectron

ca1 I

y

on

the

surface by

measuring

rates

of

temperature change

0ver

a

repetitive

time interval

. It

js

normal ly

run

simultaneously

w i th

the

absol

ute

temperature curve.

26


27/75

RADIOACTIVE

TRACER

SURVEYS

A

Radioactjve

Tracer

Survey evaluates

flow

characteristics

both

j

ns i de and

outsj

de the

wel I bore.

A

tracer

survey

i

nvol

ves

releasing a

dose

of

radjoact ive

materjal

in

the

wellbore

and

then

trackng

and

t imjng

its

movement

with a

gamma-ray

tool.

This

type

of

survey offers

versatil

ity

in fluid

flow

analysis

because

tracer

materials

can

be

selected

which

are

in

the same

phase

(o1,

water,

or

gas)

as

the

fluid

desired

to be

measured,

and

which

have

the

i

nherent abity

of

gamma

rays

to

penetrate

ayers

of

p

jpe

and

cement,

a l

I owing

tagged

f I uids

to be

traced

outs

jde

the

wel I bore.

By definjt i

on

a

gamma-ray

is

the

spontaneous

emjssion

of

energy

as

the nucleus

of an

unstable

atom

djsintegrates.

These

gamma-rays

can

be

detected

and measured

by

using

e ither

a

Geger-

Mueller

detector,

or a

sc i ntillat i

on detector.

In normal

ojl

field

use

the G-tvl

detector

js

preferred

because

of

jts

ruggedness, and

jts abity to

withstand

the

v i

brations

and

shock

f

ound

i n

a

produc i

ng or

i

niecti ng

wel

l

.

By far

the

most

common

radi

oacti

ve

tracer

used

j

s

the

isotope

Iodine-131.

I-131

is used

ma i n1y

for

jts

short

half-life

of

8.05

days.

Half

-l

ife

i

s the amount

of

time

required

for

the

isotope

to decay

to

one

half

of its

origna1

ntensty.

The

amount

of

rad

j

at

j

on

i

s

measured

j

n

Curi

es,

wi

th

one

Curi

e

equaling

3.7 X

1010

disintegrations

per

second.

For

tracer

survys,

a

Curie

is

a

large

amount,

so

the millicurje,

oF

i/1000

27


28/75

of

a Cur

e, i s used.

A

typ ica l

Radi

oacti

ve Tracer

Survey

uses

no

more

than

l0

mill i

curie of

radioactive

material

.

Another.important

property

wh i

ch

one must

cons i

der when

selecting a sujtable

R/A

tracer is jts

energy

level.

The

energy

level of a rad i

oactive

materi al

is measured

by

jts

penetrat i

ng

ab l

ity,

and

expressed

in unjts

of millions

of

electron

volts

(MEV).

The

hgher the

MEV level,

the

greater

the

energy

of

the

gamma-rays,

and

therefore

the

greater

the

penetrating

power.

I-

131

has

a

relatively medium

MEV

level of 0.364.

As stated

ear i

er,

tracer

materi al

can be

tai I ored

to match

whatever

phase

i

s

present

to

be

measured.

Actual I

y,

the carrj

er

of

the R/A material is

such

that it is

compat i ble with

the fluid

to be

analyzed.

There

are

water-based,

ol

-based,

and

gas-based

tracers

avai

I

abl

e. The tracer

materi al

must

be neutra

I

y

buoyant

in

the

fluid that

i

s to be measured.

There are

two methods

empl

oyed to transport

the

R/ A

materi

al to

the

po i

nt

i

n

the

wel

I

bore

where

the

survey

j

s

to

take

p1

ace.

The most

common method

i s to

use

a

downhol

e ejector

tool. The ejector

tool

can be

thought

of as

an

electro-

mechan

i cal

syri nge.

The

R/

A

tracer materi

al

j

s

stored

j

n

a

cyljnder

which has a

piston

ol

one end and

an

eiection

port

on

the other.

The

p i

ston

js

activated

by

a

motor

whjch

is

controlled at the surface by the operator.

Normal

tool

capacitjes

range

from 30 to 100

cc s.

Any sjze slug

may be

released

at

any

g i

ven time.

The

other

method

used

to

introduce

the

tracer

materi al

to the we I bore,

i s to

j

niect

i t from

the

28


29/75

surface.

The majn

d i

sadvantage

of

this

technique

is

that

usually

the

slug

is

widely

dissipated

by

the time

i

t

reaches

the

area

of interest;

nevertheless

this

method

is sometimes

the

ony

alternatjve

when

areas

such

as

an

annulus

need

to

be

surveyed.

Most

quant

i

tati

ve tracer

surveys

are

cal

cul ated

by

measurj

ng

the vel

oci

ty of the wel

I

fl

uj

d.

Vel

oc ty

can

be

defi

ned

as

distance

traveled/unit

of time,

(e.9.

miles/hour,

feet/second,

etc).

By i

ntroduci

ng

a

s

ug

of R/ A materi al

i

nto

the

fl owstream,

and

then

measuri

ng

the amount

of

t ime

requi

red

f

or

i

t to travel

a

gi

ven di

stance,

the

average

vel ocity

of

the

fl

owstream

can

be

calculated.

Typcally,

units

of barrels

per

day

are

used

n

f l

uid

prof

l

i ng.

By measuri

ng

the

ve

oc i ty of

the desi

red

f l

uid

we

can

calculate

jts

rate

in B/D by

the

following:

RATE_FACTORXDISTANCE

Where:

RATE=BARRELS/DAY

FACTOR=BARRELS

PER

LINEAL FOOT TI1 lES

THE

SECONDS

IN A

DAY

DISTANCE=DISTANCE

IN

FEET THE

RIA

SLUG TRAVELED

TIME=Al\4OUNT

OF TIME

IN

SECONDS FOR

R/A

SLUG

TO TRAVEL

DISTANCE

USED

For exampl

e:

seconds

A

R/ A

s

ug

travel ed

200

i n 2-3/8

tubi ng

i n 28

FxD

There are

several

velocities.

Some

are:

RATE

=

RAT

E

(

Factor

deri

ved

from

tab

e)

d

i fferent techn

i

ques

emp

oyed

to measure

333

x 200

______28-

RATE

=

2379

B/D

velocty

shots

eocity

shots

echnique

tor

rV

st

I

2

3

4

Sng

e

detec

Dual detecto

Multiple

pas

Drop check

29


30/75

Aj

though

i

t

j

s

not a ve oci

ty

measurement,

another

techni

que

that

w i I I

be dj scussed

i

s the

percent

I oss tracer method

.

30


31/75

SINGLE

DETECTOR VELOCITY

SHOTS

In ths method,

the tracer ejector

tool is

placed

a

known

d i

stance

above

the

gamma-ray

tool.

The

tool string is

paced

in

the wel

I

bore where the ve1

oc ty i s to

be obtaj

ned

and hel

d

stati

onary.

l^lhen

the R/

A materi

al

i

s rel eased f

rom the

e

jector

tool

,

i

t

mi xes

wi th the fl owstream and

i s

carri ed down

past

the

gamma-ray

tool . At the

surface the recorder

i s

p l

aced

on

ti

me-

drive. When

the slug is

ejected from

the

tool a mark

is recorded

whi

ch

s tme zero. The

recorder

then

moni

tors

background

radiation as

the slug

approaches

the detector.

As the

slug

passes

the

detector, ts

peak

intensty

is recorded.

Because

the

recorder

i

s

on time dri

ve, the I

og

i s

a

functi

on

of time.

The

i nterval

between the

two

peaks

i s measured and

correl

ated

to a

time

expressed

in

seconds. The

previous

equation

can

then be

used

to deri ve the rate

i n B/D.

To

obta i

n mul ti

p

e vel oc ty

shots

jn injectjon

we11s,

the

loggng

tools

are

lowered

to

the

I owest

zone

of i nterest

and

a

rate i s

obtai

ned.

The tool

str

ng

is then

rajsed

to

the next

station

and

the

process

repeated.

The

statjons chosen are usualy

sections

of blank

ppe

between

perforated

i nterval

s.

Pl

otti ng

these

vel

oc

i

ty shots of

rate

versus depth wjll

provjde

an njection

profile.

31


32/75

o

I

R/A

EJECTOR

DISTANCE

TRAVELED

GAI}IT} A-RAY

DETECTOR

SINGLE.DETECTOR

GAMMA.RAY

VELOCITY

SHOT

32


33/75

U DE

ECTO

VELOCI Y

The

dual

detector

method utjlizes

two

gamma-ray

detectors

whjch

are run

simultaneously

and

spaced

a

known

distance

apart

to

obtain

the travel distance.

The

detectors

have

opposite

output

pu l

ses

whi

ch

are

sel ectvey di

scriminated

on the surf ace.

Instead of recording

the

time

for a sug

to

leave the eiector and

pass

the detector, this method measures

the time

for

an aready

wel I

mj

xed

s

ug

to

pass

each of the two detectors.

Thi

s method

is

more

accurate

jn

lamjnar

flow s ituat i

ons, because

i

t

allows

the R/

A

materi al

to

become

better mi xed

j

n the fl

owstream.

The

logging appicatjon

is identical

to that of the

snge

detector

method, w i

th the tool

string

held statonary

at

the areas

to be

investgated,

fld

then

moved

to

the additional

stations.

0n

the

surf ace,

each

gamma-ray

curve i s

recorded on the

t ime

drive

independent of the

other. The time interval is measured

between

the two

gamma peaks.

33


34/75

o

I

I

R/A

EJECTOR

TOP

GAMMA-RAY

DETECON

TRAVELED

BOTTOTI

GAMMA.ftAY

DETECTOR

DUAL -ETECTOR

aAMMA.RAY

VELOCITY

SHOT

34


35/75

MIII TT PI F PASS TFCI{N TNIIF

In many wel I

compl etions

the

po'int

of

f I

uid

exit f rom

the

tub'i ng

is

below the

perforated

jntervals

in

the

wellbore.

Th'i

s

type

of

completion

makes

it

physically

impossible

to

place

the

survey

tool

s

between the

perforated

nterval

s. In a

compl etj

on

of

th

i

s

type, i t

'i

s necessary

to

empl

oy

the mul

ti

pl

e

pass

technque.

This

'l

ogging

procedure

is

based upon

following

a

sngle shot

of R/A material

'i

n the

flowstream

and

recording

ts

peak

intensities

on depth

versus

tme.

After the

s'l ug

is

rel eased

'i

nto

the f I

owstream,

the

gamma-

ray

tool

i

s

pul

l ed up

through

the slug with

the recorder

set

on

depth

drjve.

Subsequent

passes

through

the same slug

will

show the changing

depth

of the slug, rd

by carefully

noting

the total elapsed

times

of the

peak

radiatjon

intensjt'ies,

the fluid

veloc'itjes

can

be calculated

at

the various

depths in

the wellbore.

In

application,

the

slug

is

ejected

into

the

area

of 100 total

flow

and

a rate establjshed. All

subsequent

rates

are then

measured,

and an injection

profile

is

constructed.

The multiple

pass

technique is the method

whjch

is used

jn

obtaining

an

jnjection

profjle

jn

a

single-string-multiple-packer

type

compl eti

on. f.lhen surveyi ng

th s type

of compl et on,

the

slug is released into

the flowstream

above

the

mandrel

jnjecting

into

the

zone

to

be

logged.

The

sug

'i

s

then

logged

as

it

moves

up

or

down the

annulus.

35


36/75

The

wel I

bore

velocty

multp1e

pass

technque

js

also

used

in

areas

i

n

the

where the fluid flow

is too slow

to

ut i

l i

ze

detector

shots. It

i

s

al

so

used

to

confi rm areas

of

no

fl

ow.

36


37/75

5900

PACKEN

PERFS

FLO}Y

MANREL

6000

PACKER

MULTIPLE

PASS

TECHNIQUE

IN

TB6 CS6

ANNULUS


38/75


39/75

ROP CHECK

9


40/75

PERCENT

LOSS TRACER

METHOD

Al

though the

percent

I

oss

tracer method

does not

measure

fluid velocties,

jt js

an

accurate,

guant itat ive

jnterpretatjon

of flujd loss. Also called the

self-method,

th i

s

technique

measures

fluid

losses

in

jnjectjon

wells

by measurjng

the

amount

of R/A material

lost

to the formation.

The

main

appcatjon

for

this method

js

to

obta in

jnjection

profjles

i

n uncased

or

open

hol

e compl etj

ons. Al I

of the fl ui

d vel oci ty measurement

methods

d i scussed

prev i

ously have assumed

that the

bore

hol

e

diameter

remain

constant across

the

i

ntervals

where the

measurements

are

being taken.

The self-method

i

s independent

of

borehole

diameter, making

it

most

su itable

for irreguary

shaped

borehol es.

The

appl

cation

of

thi s technique

i

s

identical

to

that of

the

multp1e

pass

technque.

A

singe

R/A

slug

i

s released

jnto

the

fl ow

above

the

fi rst i nterval

of fl u i d I

oss,

fld

repeatedl

y

logged

on

depth

drive until the

slug

either

disperses

into

the

format

on, or ceases to move.

Record

ng

the tjmes

of

peak

intensities

is

not

necessary

for

this

method.

After

the

sl ug has

been

I ogged unt

i I zero

fl ow

has

been

establ

i

shed,

the

chart

paper

j

s

removed

from

the

recorder.

Using a

straight edge,

the

ind i

vidual

R/A s l ugs are

trjanguated . First,

a

vertical line is

drawn

for

the

average

base line

of each run.

Next,

nes

are

drawn

along

the

sopes

of

the top

and

bottom

of the i ntens i

ty

peak.

These

I i

nes

are

extended

to i ntersect

at a

poi

nt to the r

ght

of the

j

ntens

i

ty

40


41/75

peak

and

the

base

I'ine. The

di stance f

rom

the

base I i ne

to

the

i

ntersecti

on

of the

i nterface

I i

nes

j

s

termed

the

'hei

ght'

.

The

di stance between

the

i

ntersecti

ons

of

the

'interf

ace

I

i nes

wi th

the

base

I

i

ne

i

s

termed

the

'base'

.

Start

ng wi

th the

fj rst

tracer

recordi

ng

after

the

radioactjve

material

js

dispersed

jn

the well

fluid,

the

heght

and

base

of the recorded

curve

are

added.

Because

the

first

og

is

conducted

pri

or to

any

fluid lossn

jt'i

s

a

100 flow'l

ogging

run.

As

fl uid

j

s I ost

to

the

formation,

the I oss

j

n radj

oactj

ve

jntensity

of the

gamma-ray

recordj ng

on sUcceeding

ogg ng runs

wjll

be

proportional

to

the

amount

of fluid

leavng

the

wel'lbore.

By uslng

the

I00

flow

logging

run as a

basjs

for

comparison,

the

sum of

the

helght

and

base

of the

reduced

intensity

recordings

can

be

def i ned as a

f racti

on

of the

total

i

ni

ected

s1

ug

.

Us'ing

these

amounts

of

R/A materials

'lost'

to

the

formation,

an

i

njecti

on

profi

I e

can

be

constructed.

41


42/75

PACKER

CSG

SHOE

5'

.-r-_;

-

I

)

?-

*-__,

I

(*

--__-

--)

FROM

-:

CALIPER

LOG

..

a

I

\

\,

t '

e'

al

'-'

\\-r

t

f'

'--i-

I

,

a-\\\\

\

t

NREaULAR

SHAPED

SOREHOLE

--\_

,:

t

I

,

PER-CENT

LOSS

TRACER

METHO

42


43/75

OTHER USES

Because of

the

tracer

materi al

s

abi l

ity

to

m

j

x

wi

th the

fluids

belng

measured, fluid movements

can

be

traced

anywhere in

the

wellbore

that flujd s

moving.

Tracers

are

commonly

used

to

check

the

mechan

jcal jntegrity

of f

I

u id

sol at ion

dev ices such

as

packers, plugs,

casing shoes, I iner

hangers,

water-shut-offs,

fl oat

co

1

ars,

cement

squeezes,

etc,

Tracers

are

very often

used

to

check

the extent

of

channeing and

fluid m igraton.

As long

as

a

small

quantity

of

R/A material

can

be

paced

jn

the

fluid

system

to

be

anayzed, a

quantitat ive

as well as

qual

jtatjve

conclusion

can usually

be

drawn.

43


44/75

SPINNER/FL0HI4ETER

The

spinner/flowmeter

js

a

logg ing

jnstrument

which

js

used

to

measure

the flow velocity

of

a

flujd within

the wellbore.

It

consj

sts of

an

mpel

I

er

mounted

on

a shaft

whi

ch

i

s

coupl

ed

to

some

type

of

sendng

device;

usuay

magnetic.

When the

tool

is

p1

aced

i n a

fl

ow-stream

movj

ng

above

a

certai n

mi

nimum

vel

oc

ty,

the

impeller

will

sp in

at a

rate I inearly

proportional

to

the

flow

velocity. The

mpeller, in

turn, cuses

the

sending

dev ice

to spn

at

the

same

rate

which

produces

an

electronjc

signa 1.

The

sgnal

js

then

amp l

ified,

condjtioned, and

sent

to

the

surface via

the wireline.

An

i

ncrease

or

decrease of

the

fl

u

i d

fl

ow

past

the

tool

i s

sensed by an

increase

or decrease

jn

the frequency

of the

output

sgna l

which

is directly

proportional

to the

RPM s

of

the

rotatng mpeller

blade. These

changes

in

RPM s

can be

d irectly

related to

changes

i

n the

amount

of

flu

jd

moving

jn

the well.

Knowing

where

the jntervals of fluid loss or

ga i

n are

jn

rel ati

onshi

p

to the

wel

I

bore

enabl

es one to

construct

the

fl

uid

prof

1e.

There are three

bas ic types

of

spinner

tools used

in flujd

profiling.

These are:

1) Inflatable

packer

flov lmeter;

2)

The

continuous

spinner/ f

lowmeter;

and

3) The full

-bore

sp i

nner/

fl

owmeter.

The i nfl

atabl

e

packer

fl

owmeter has

an

i nfl

atabl

e

bl

adder

affixed be l

ow

the

mpeller.

The tool

js

postioned

in

the

wel I

bore

where

the vel

oci

ty

readi

ng

i

s to

be

taken. The

tool s

44


45/75

are

hel

d

stati onary

whj I

e the bl

adder

i s

j

nfl ated.

When

the

bladder

is fully

inflated,

jt

forms a

'packer'

aganst

the

wel

I

bore.

Al

I

of the wel

I fl

ui

ds are

forced

through

the

bl

adder

and

across

the

meter

ng

sect

j

on

.

The

advantage

of

.

th

j

s tool

j

s

that 100

of the fluid flow

can be

measured at

any

g'i

ven

point

in

the

wellbore.

The disadvantages

of this tool are:

1)

it is very

ted ous

and

time consum'i ng;

2) the

bl

adder

i s of ten

damaged

by

bad

casng

and

rendered

inoperable; and

3)

the

tool has a

maximum

fl uid

vel

octy

that it

can

measure

without

bejng hydraul

jcal

ly

forced up the

hole.

Because

of

the

many

djsadvantages

assocjated

wi

th the

packer-fl

owmeter, i

t i s rarely used

and i

s

currently

bej ng

phased

out

j

n

most

areas.

The contnuous

spnner/flowmeter

is,

by far,

the

most

widely

used

spnner

today.

The

general

design of

thjs spinner

js

shown

'i

n

the illustration. The

tool

js

of

generally

simple

desgn,

rugged

construction,

fld

can

pass

read

y

through

most

types

of

tub

ng

compl

eti

ons.

The

impel

I

er

on thi

s tool

i

s

general

ly I/4'

smal I er

than

the maxj mum

0.

D.

of

the

tool

stri ng.

The

bow-

spri

ng

type centralizers ajd

in

the

centering

of

the impeller in

the

wel I bore where the area

of

most

tui.bul

ent f I

ow

oe e

u'rs.

As i

ts

name implies, thjs

spinner

is

run as

a

continuous,

uhinterrupted

survey across

the

j

nterval

to be

1 ogged. Advantages

of thj s

tool

are: 1)

i

ts

ruggedness;

2)

i

ts

f I

ex'i

bl

e

construct'i

on

al

I owi

ng

j

t to

pass

freely

through

tubi

ng

and

other

restri

ctj

ons;

3)

comparati

vel

y

I ow mai

ntenance;

and

4) reduced

ogg

ng

times

as

a

result

of bejng

able

to run a

c0nt'i

nuous

survey,

as

opposed to

45


46/75

one

jn

which

the tools must be stopped,

and

stationary

readngs

taken. Disadvantages

of thjs tool

are:

1.)

its relatively high

by-pass;

(

i

.e.

,

the

mi

njmum

amount of fl

ui

d fl

owi ng

past

the

impeller before it starts to turn); and 2.) it's lack

of

sensi ti

vi

ty

to

smal

I

changes

compared

to

the other types.

The

full-bore

spinner/flowmeteri

s

a

compromjse

of the two

previ

ous sp'i

nners. There are two types of

f ul I

-bore

sp'inners:

1.

)

basket-type

spi nners

;

2.

)

and

des'igns

impl ementi ng a I arge

diameter

impeller

blade.

The

basket-type

spnner is similar

to

the

packer-fl

owmeter,

but

i

t

uti I izes

a

co1

apsi

bl e basket

to

divert

neary

all of the flujd

past

the

mpeller

blade.

This

sp'i

nner has

the advantage

of be'i ng

abl

e to be

run conti nuously

across the wel

I bore. It

wi I I

al

so

co'l

apse

to

al

I ow

passage

through

restr

j

cted di

ameters. The

arge

di

ameterimpel

I er

type

utjlizes a spinnelimpeller

whose

sjze

is

80

to

90

of

the

insjde

diameter

of the

pipe

bejng

logged.

The desgn

of this spinner is

hghly

compl

icated

and

quite fragile

due

to

the

necessity

of

the

'impeller

blade

to fold

up while the

tool is being conveyed

through the

tubi

ng.

Advantages

of thi

s

tool

are: I

)

i

ncreased

sensjt'ivities

for better

response

at lower flow rates;

and ?)

tool

is faster

to

run as

a

contjnuous

type tool

as

opposed to

one

whi ch must

be

stopped

to take i

ndj vidual

read

ngs. Dj

sadvantages

are:

l) tool

is farly fragle,

and

great

care

must

be

taken

when the tools

are

passed

through small

restrictions

as

to

not

damage

the

blades;

and

2) tool

js

a

very

high maintenance item.

46


47/75


48/75


49/75

SPINNER

TOOL

CONFIGURATION

SPINNER

SURVEY

ONJECNON

VELL)

RPMs

INCREASES

PACKER

rAL

CASING

SPINIIER

15

RUN

OPPOS|w

OIRECTION

OF

FLUID

FLO U,

AREAS

N

VELLBONE

OF FLUID LOSS

OW-SPRING

CENTNALEER

o/o

FLUI FLOW

o

50

too

TD

SPINNER /

FLOWMETER

49


50/75

FLUID IDENTIFICATION

When

runnng

a

fluid-entry

survey,

jt

is necessary

to

i denti fy the type of fl ui

d

as

i t enters the wel I

bore. The

identifjcation

js

accomplshed

wjth the aid of Fluid

Identification tools,

these tools must

be

able

to

djfferentjate

between

the d i f f erent

phases

present

in

the wel

bore, such as

oi

l

-tntater,

o

j

l

-gS,

or

o i

l

-water

and

gas,

and

al

so

be

abl e

to

pi

npoj

nt

the

prec i

se

I

ocati

on of these entri

es

j

nto

the

wel.l

bore.

There

are

two types of these

.

tool

s current

y

j

n use today

the

capacitance

tool,

and

the fl ujd-densjty tool

.

CAPACITANCE TOOL

By defjnit i

on, capacjtance is the

property

of

an

electric

nonconductor wh

i

ch

perm i

ts the storage of

energy

as

a

resul t of

el ectri

c

di

spl

acement when

oppos i

te surfaces of the

nonconductor

are

maintajned at a djfference

of

potent i

al.

Stated

simply,

capac itance

j

s

the measure

of

the

ab

1

ty of

a

dev

j

ce, such

as

a

capacitor, to store

an

electrical charge. A

smpe

capacitor

consi sts of two conducti ng

pl

ates

separated

by some non-

conducting substance whjch is

called

dielectric

materjal.

When

one

of

these

pl

ates

j

s charged

w ith an

el

ectri

cal

f

orce,

and

the

other

pate

he. d at the

opposite

potential

,

jt

is sajd

to

have

capacity.

There

are

three

parameters

whj

ch

affect

the

capaci

ty of

any

capacj

tor:

I

)

The

type

of

dj

el

ectri c

materj

al

2)

The

size of the

conducting-plates

3) The

dstance

between

the

pates

50


51/75

P

L

A

T

E

NEOA

AELECTRrc

MATERIAL

POS|nVE

CHAR6E

CHARGE

EASIC

CAPACITOR

The

probe

of

the

capaci

tance

tool i s

des

i

gned

to

act as

a

capacjtor. It

consists

of

a

conductng cyindrjcal

probe

wh i ch

is

insulated

from the tool body.

This

probe

functons

as

one of

the

plates

of

the capacjtor.

Surrounding

thjs

probe

is

a

cage

which

allows the well flujds

to

pass

freely

through

jt.

This

cage

acts

as the opposjte

plate

of the capacitor. Sjnce ne i

ther

the size

nor

the djstance between

these plates change, the

ony

parameter

I ef t whi ch

determ i

nes the capacity

i

s the type

of

dielectric

matera1,

which

is

the

wellbore

flujds

flowing

between

the

probe

and

cage.

The

unit

of

th i

s

measurement is

termed

the

dielectric

constant of the flud(s) fowing between the

plates .

The d i electric constants for urellbore flujds are:

DI

ELECTRIC CONSTANTS

GAS 1.O

OIL

2.8

T0

3.0

WATER 60 TO

80

P

L

A

T

E

51


52/75

As can be

observed from

the chart, the

capaci tance

tool

j

s

most

sens

j

ti ve to

changes between

o

i I

and

water. A

eapacj tance

survey

actually neasures

the amount

of

hydrocarbons

present

in a

col

umn

of

water.

In

use,

the survey

js

started

in

an

area

above

the

producing

zones and

I

owered s'low1y

down. The

I og

j

s

run downward

to oppose

the djrectjon of

fluid

flow. Usua'l

ly

three

or more

logs

are

run

to

insure repeatability, 0d

to

make.ce ta'in

that

the well

is

produci

ng

under

stabl

e condi

ti

ons.

The

.tool

can be

cal'i

brated

using an

.i

n-

Documents

Production Logging- Field Session