6 mud removal cl 24 jun 00 a

7/24/2019 6 Mud Removal CL 24 Jun 00 A

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Mud Removal

Module CMT 01826-Jun-00


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Objectives of PrimarCementation

Provide com!lete isolation of "ones

#$draulic %ond&

To su!!ort t'e casin(

#)'ear %ond&

Protect casin( strin(


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Mud Removal

Most im!ortant as!ect of cement job

* t'ree ste! !rocess before cementin(

$ole cleanin(

Conditionin( t'e drillin( +uid ,is!lace t'e drillin( +uid from t'e

annulus


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Mud Removal $ole Cleanin(

Controlled o!timi"ed mud !ro!erties

.i!er tri!s

/ Total 'ole volume in circulation

Cali!er lo(

Conditionin( Mud

%rea3 (el stren(t'

4o5er t !v

,rill solids 7 6

,etermine MP to 9nd :min for all-around +o5

,is!lace Mud from *nnulus

O!timi"ed slurr !lacement ---/ CemC*,; Casin( centrali"ation o!timi"ed #)TO /


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Criteria for ;=ective MudRemoval

Cementing Operation:

Centralize casing

Casing movement Scratchers

Wiper plugs

Washes and spacers Flow regime selection


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T'e >deal .ellbore Casin(

Thin, impermeable mud filter cake

(not gelled or unconsolidated)

BHST at top of

cement

>BHCT at TD

Annulargap

inimum! "#$%

&deal! ' '#%

roperl* conditioned

hole and mud

+auge

diameter

o sloughing

-niform as possible( no .ashouts or restrictions)

/ 01/2/ 1/SS3S

Casing centered in borehole

Accurate BHST and BHCT


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?luid Cali!ers

To determine circulation e@cienc or amount

of +uid 5'ic' is movin( in t'e 5ellboreA Procedure B

Run multi-arm o!en-'ole cali!er lo( anddetermine total 'ole volumeA

Circulate at cementin( rate and determinemud !um! e@cienc

,ro! mar3er or tracer in sta(ed intervals

Monitor returns for mar3er

Calculate volume circulated from rate and time#)'ould be mec'anical cali!er volume&

>ncrease rate and re-calculate e@cienc


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>n+uence of t'e Casin()tand-O=

44narnar 44.ide.ide

DDii

DDoo


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De5tonian ?luid - ;=ect of

)TO The Efect o the Casing StandOf on the !nnular

Flow is "ualitativel# E$uivalent to the Following Flow%attern

55

DD'' DD

4444''

55

11

11


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4aminar ?lo5 in ;ccentric*nnulus

on6parallel plate model 7i#7o 8 9:;

9 '9 9 "9 $9


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Turbulent ?lo5 in ;ccentric*nnulus

9 '9 9 "9 $9


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Casin( Centrali"ation

7elatie 4ariation of flo. rate ratio as a function of eccentricit*7elatie 4ariation of flo. rate ratio as a function of eccentricit*

';

'=

'$

'

'9

;

=

$

9

9 9 $9 =9 ;9 '99

22

@ Stand6off 8.

7H6 7C '99

A& @ STAD6/00

01/27

AT37AT&/

7C

7H


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T!es of Centrali"ers

&ow Spring 'Spiral or Straight(: Fle)i*le *ow springs

Centralizer O+ slightl# larger than O, size

-igid &ow 'or %ositive( t#pe:

.on/e)i*le O0+0 'Slightl# less than previous casing 1+(

2se inside casedhole sections

Efective in ingauge O, intervals onl#

-igid Solid slipon t#pe: Solid *od# no *ows

2se: as per rigid t#pe


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%o5 )!rin( Centralisers


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.eat'erford )!ira(liders


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Reci!rocation Movement of casin( u! and do5n durin( t'e job

Must be done from t'e start of circulation to enddis!lacement

20 to E0 feet stro3e

1 to minutes !er ccle

Deeds scratc'ers to be e=ective ,*D;R B Casin( ma become stuc3 durin(

movement

;Fcessive s5ab and sur(e !ressures ma be created

;Fcessive !ull and buc3lin(

Cannot be t'e onl met'od of mud removal


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Rotation

Circular movement o pipe

3ust *e done rom the start o circulation to enddisplacement

45 to 65 rpm

Scratchers help e7cienc# .eeds special rotar# cement heads and power

swivels

Tor$ue must *e ver# closel# monitored

Cannot *e the onl# method o mud removal


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?luids >ncom!atibilit -esults 1n:

+etrimental 1nterace -eactions

,igh -heological %roperties

8er# high viscosities

8er# high gel strengths

Change in Cement Slurr# %roperties

Thic9ening time altered

1ncrease in /uid loss

-eduction in compressive strength

-eduction in ,#draulic &ond

%revented : Wiper %lugs

Chemical Washes

Spacers

Compati*ilit# Testing


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Cement .i!er Plu(s

eep Fluids Separate in Casing and -educeContamination

&ottom %lugs

-emove mud ahead o cement

%revent cement alling through lighter /uid ahead Wipe inner casing walls clean

2se ; or more i possi*le

Top %lugs

Separate cement rom displacing /uid

%ositive indication o end o displacement

. t' f d D R t ti


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.eat'erford Don-Rotatin(Plu(s


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.' Run a %ottom Plu( G

&ottom plug wipes accumulated mud ca9e!3%?E: @ ABD 6 l*Bt 45555 eet< collar at @;5

eet

8olume o 4B4D =lmG

,eight corresponding to this volumeG

T b l t ?l


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Turbulent ?lo5,is!lacement

%reerred and *est /ow regime

Critical rate depends on: Fluid rheologies Casing standof

!nnular gap< casing O+ and *it size

Formation racture gradient

2se Chemical Wash andBor 3udpush >TBS spacers: 45 3in0 Contact time or A5 t 'use greater volume((

Spacer densit# to *e close to that o mud

Optimize cement slurr# properties: 3inimum %8 and TH without settling

Fluid loss and ree water controlled Water wet the casing and ormation


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;=ective 4aminar ?lo5 !lternative /ow regime when Tur*ulent /ow is not

possi*le Four criteria must *e satis=ed:

+E.S1TH +1FFE-E.T1!? '45I(

31.1323 %-ESS2-E J-!+1E.T '3%J(

F-1CT1O. %-ESS2-E ,1E-!-C,H ';5I(

+1FFE-E.T1!? 8E?OC1TH C-1TE-1O.

8iscous spacer: 3udpush >?B>?O 8iscosit# adKusta*le 'Change +46@ concentration(

8olume to use: A55 t or 5 **ls

2se ;5 65 **ls chemical wash Condition and clean mud

8iscosi# cement slurr# when necessar#


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C'emical .as'es Water *ased /uids< low viscosit#< densit# o water

Eas# to pump in tur*ulent /ow CW or intermediate casings< water *ased muds

640A gals water< 50A gals +4;;!

CW455 or production casings< water *ased muds

640;A gals water< 50A gals +4;;!< 50;A gals L;M CW or intermediate casings< oil *ased muds

640;A gals water< 50A gals +4;;!< 50;A gals F65 last

CW454 or production casings< oil *ased muds

64 gals water< 50A gals +4;;!< 50;A gals L;M< 50;A galsF65


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?amil of )!acers

32+%2S, >T Tur*ulent spacer or water *ased muds

32+%2S, >S

Tur*ulent /ow spacer or water *ased muds in

saline 'Salt( environments

32+%2S, >?

Efective laminar /ow spacer or water *ased muds

32+%2S, >TO< >SO< >?O also e)ist !pplications are same as a*ove *ut in O1? &!SE+

32+S0

Re:uired Pro!erties of


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Re:uired Pro!erties of)!acers

Compati*le with all other well /uids

Sta*ilit# 'good suspending capacit#(

Controlla*le densit# and rheolog#

Jood /uid loss control

Environmentall# sae and eas# to handle in the=eld


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;vents to be Recorded

Was the mud conditioned rate and timeG

,ow man# centralizers were run and whereG Was the casing rotated andBor reciprocatedG

Where the plugs correctl# droppedG

What was the densit# and rheolog# o the spacersG

Was the correct volume o pre/ushes usedG The ollowing data must *e recorded on the %-1S3:

!ll densities< i possi*le o displacement /uid as well

!ll /ow rates< i possi*le o displacement as well

!ll pressures

.ote an# changes in /ow rate< densit#< stoppages

6 mud removal cl 24 jun 00 a

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