CmtPrac2004Sec2CmtAdditives

5/27/2018 CmtPrac2004Sec2CmtAdditives

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Cement AdditivesCement AdditivesSpecific Materials for

Optimum CementPerformance


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Shorten Initial Set Time

and AccelerateCompressive Strength

Development


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Calcium Chloride Most widely used

2 to 4% (bwoc)

40 to 120 F

Anhydrous, regular, powder, liuid

Sodium Chloride (Salt)

!sed when calciu" chloride is not pre#erred $ot as e##ectie as calciu" chloride

Accelerates at low concentrations

& to 12% (bwow)

'ecreases iscosity

ncreases #luid loss 0 to 120 F


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Densified Cement

0* to 1*0% 'ispersant &*1 to &*4 gal+s water

-igh co"pressie strengths

Seawater

.oastal areas Mi/ing water (no cost)

.ontains 1* to 2% soluble chlorides

ehaes si"ilarly to 1% calciu" chloride


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Slow Cement HydrationTo Allow For

Safe Cement Placement


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Calcium lignosulfonate

Sodium lignosulfonate

Blend of calcium lignosulfonate &organic acid

CMHEC

Organic acids

Synthetic retarders


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Lower Mixing Viscosityand Decrease the Rate

for Turbulent Flow


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Lower Fluid Loss Rateof Cement SlurryDuring and After Placement


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Bentonite

Organic polymers (cellulose)

Organic polymers (dispersants)

Latex additives


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Lower Hydrostatic Pressureand Improve Slurry Economy


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Bentonite

Attapulgite

Diatomaceous earth

Pozzolan Gilsonite/Coal

Fumed Silica

Perlite/Hollow Microspheres


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Lightweight AdditivesLightweight Additives

Bentonite/Attapulgite wells 10 ti"es its original dry olu"e

'ispersant o#ten used to control iscosity (3 % gel)

4 to ti"es less gel is reuired i# it is pre5hydrated alt will reduce the yield

!p to 16% (7 00 F)

Anhydrous sodium metasilicate 1 to &% (-.8 7 200 F)

9iuid (0*6& gal+s)

'i##icult to retard

$ot reco""ended with: Calcium chloride

Salt at high concentrations


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Pozzolanic Materials (Fly Ash)Pozzolanic Materials (Fly Ash)

Decreases Slurry Cost

Lightens Slurry Weight

Enhances Pumpability Reduces Permeability

Promotes Bonding

Improves Chemical Resistance

;educes sul#ate attac ;esists corrosion #ro" seawater

-as so"e acid resistance


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Fumed SilicaFumed Silica

High Surface Area Silica

Primary Functions


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Foam CementFoam Cement

Advantages Economically competitive

Excellent strength to density ratio (low

permeability) Reduces filtrate loss

Settling Control

Imparts compressibility

Combats annular gas invasion

Controls high volume water flows

High temperature cementing (< 600 F)


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Heavyweight

Additives

Increase Slurry DensityTo Control Formation

Pressure


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Hematite ore (5-5.2 S.G.)

Barite (4.9 S.G.)

Hausmannite ore (4.9 S.G.)

Sand (2.65 S.G.)


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Improve Bond ofCementto Pipe and Formation


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Aluminate-sulfate additives and cements Polyvalent metal oxides

n-situ !as !ene"ato"s

#om$"essi%le cements


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Prevent Annular Gas

Migration


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GasGas

MigrationMigration Gas flows

Through Un-SetCement After

Loss ofOberbalancePressure

Flow through

unset cementleads to channelin set cement

>as

.hannel


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Prevent and Release

Entrained AirWhile Mixing Cement


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DefoamersDefoamers

Decrease Foaming Tendency

Minimize Air Entrainment

Improve Density Measurements

Common Foamers or Air Entrainers alt (seawater, ?.l)

ur#actants (9ate/ syste"s)

9ignin type retarders

entonite slurries

If Used in Foam Cements, Determine That theFoam is Stable


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Prevent Loss of Whole

FluidBefore and During

A Cement Job


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Lost CirculationLost Circulation

ProblemsProblems Low Fracture

Gradient

UnconsolidateFormations

Fractured

Formations Cavernous

Formations


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Granular (gilsonite, coal, perlite,walnut hulls, mica)

Fibrous (nylon, polypropylene)

Lamellated (cellophane) Specialized flash setting or gelling

materials


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Lost CirculationLost Circulation

Unconsolidated or Highly PermeableFormations

=er"eability e/ceeding 100 darcies

>radual loss o# #luid


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Lost Circulation MaterialsLost Circulation Materials

Granular Asphaltene+.oal

4 to 100 mesh (1.07 S.G.)

5 to 25 lb/sk (< 230 F)

Avoid bottom plugs when using bridging agents

@alnut hells Course, medium, and fine grind

1 to 5 lb/sk (< 290 F)

=erlite+-ollow Microspheres

Expanded volcanic rock/ lightweight cellular material 0.5 to 1.5 cu.ft./sk (< 260 F)


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Granular >ranulite 8; 1+4

4 to 16 mesh Ground Tires (1.14 S.G.)

1 to 3 lb/sk (< 400 F)

Avoid bottom plugs when using bridging agents

=er#ect eal 16 to 100 mesh Graded Ceramic (1.5 to 2.5 S.G.)

1 to 5 lb/sk (< 1000 F)


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Laminated 3/8 to 3/4 inch cellophane flakes

1/8 to 1/2 lb/sk (< 260 F)

Fibrous Fibrous material (unstranded rope) Provides shatter resistance to set cement

1/2 to 1/8 lb/sk (< 260 F)


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BDO-Bentonite-Diesel Oil Slurry Aoid water conta"ination (oil based spacer is reuired)

BCDO-Bentonite-Cement-Diesel Oil Slurry

DOB2C-Diesel Oil-Bentonite-2 sacks Cement

DOC-Diesel Oil-Cement Slurry


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Salt

Silica flour

Tracers

Dyes

Gypsum

Special AdditivesSpecial Additives


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Strength Stabilizing AdditivesStrength Stabilizing Additives

Fumed silica effective to 275 F

Fine crystalline silica =reents strength retrogression

&% (or greater) when -8s 3 2&0 F

etter suspension

Coarse crystalline silica a"e application as A51

-eay weight slurry applications


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Salt CementingSalt Cementing

Flowable Salt Zones =lastic #low

.auses casing de#or"ation or collapse

=reented by proper "ud displace"ent and rapid strengthdeelop"ent o# ce"ent

alt added to ce"ent not i"portant

Foa"ed ce"ent typically e##ectie

Non-flowable Salt Zones onding to salt Bone critical

aturated salt slurries reco""ended or

Foa"ed ce"ent slurry containing 1% salt

e care#ul not to oer5retard

Documents

CmtPrac2004Sec2CmtAdditives