13- Drilling Fluid Final

8/13/2019 13- Drilling Fluid Final

1/20


2/20

TABLE OF CONTENTS

Drilling Fluids

Unit Objectives...............................................................................................3

Drilling Fluids..................................................................................................3

Drilling Fluid Classification Systems...............................................................9

Drilling Fluid Additives..................................................................................1

!aterial "alance #$uations..........................................................................1%Oil&"ased Drilling Fluids...............................................................................1'

Drilling Fluid #conomics...............................................................................1(

Drilling Fluids %


3/20

UNIT OBJECTIVES

)ecogni*e t+e com,onents in t+e various ty,es of drilling fluids.

#-,lain t+e advantages and disadvantages of t+e most common ty,esof drilling fluids.

rovide an e-,lanation of mud ,ro,erties as t+ey are re,orted on a/morning re,ort0.

Calculate barite and ater volumes +en c+anges are made to a ,re&e-isting mud system.

Calculate 2 and from Fann viscometer readings.

DRILLING FLUIDS

A drilling fluid is any fluid +ic+ is circulated t+roug+ a ell in order to removecuttings from a ellbore. 4+is section ill discuss fluids +ic+ +ave ater oroil as t+eir continuous ,+ase. Air5 mist and foam5 +ic+ can be used asdrilling fluids5 ill not be discussed at t+is time.

A drilling fluid must fulfill many functions in order for a ell to be drilledsuccessfully5 safely5 and economically. 4+e most im,ortant functions are6

!ud assists in ma7ing +ole by6

1. )emoval of cuttings%. Cooling and lubrication of bit and drillstring

3. oer transmission to bit no**les or turbines.

!ud assists in +ole ,reservation by

8. Su,,ort and stabili*ation of bore+ole all

. Containment of formation fluids:gas.

'. Su,,orts t+e eig+t of ,i,e and casing

;. Serves as a medium for formation logging

(. revents +ole as+ outs due to turbulence or dissolution

9. !ust be com,atible it+ drilled formations and encountered formationfluids:gas.


4/20

Make-up ! a Drilling Fluid

and some sort of viscosifying agent. a ,ortion of t+e fluid ill be flus+ed intot+e formation. Since e-cessive filtrate can cause bore+ole ,roblems5 somesort of filtration control additive is generally added. .


5/20

=b> Can be used alone or it+ t+inners

=c> 4+ey also reduce viscosity

=b> Used under more severe conditions t+an ,+os,+ate treatment

4+e u,,er ,ortions of most ells can use /normal0 muds

1. Care must be ta7en not to add c+emicals +ic+ may +inder t+e ma7ingof s,ecial muds later on

%. Bative clays used to ma7e t+e mud are usually ade$uate

Spe#ial Drilling Fluids

4+ese drilling fluids are made to combat ,articular abnormal +ole conditionsor to accom,lis+ s,ecific objectives. 4+ese are6

1. S,ecial Objectives

=a> Faster ,enetration rates

=b> reater ,rotection to ,roducing *ones

%. Abnormal ole Conditions

=a> ?ong salt sections

=b> ig+ formation ,ressures

Drilling Fluids


6/20

Drilling Fluid Classi!i#a$ins

. Drilling fluids are separated into three major classifications (Figure 1):

Pneumatic

Oil-Based

Water-Based

Drilling Fluids '


7/20

Li"e Base Muds

1. @ater base mud

%. 4reated it+ large amounts of caustic soda5 $uebrac+o5 and lime.

Added in t+at order

3. )atio of % lb caustic soda5 1. lb $uebrac+o and lb lime ,er 1 barrelof mud

8. @ill go t+roug+ a +ig+ly viscous stage5 but ill become stable at a loviscosity

. ood ,oints

=a> Can tolerate large amounts of contaminating salts

=b> )emains fluid +en solids content gets +ig+

'. @ea7ness & it +as a tendency to solidify +en subjected to +ig+bottom&+ole tem,eratures

Drilling Fluids ;


8/20

Li"e-Trea$ed Muds

1. Similar to lime based mud & differ only in degree

%. A com,romise attem,t at overcoming t+e +ig+ tem,erature gelation,roblem

=a> Use less lime t+an lime&base mud

=b> Bot nearly so resistant to salt contamination

E"ulsin Muds - Oil in %a$er

1. Oil can be added to any of t+e normal or s,ecial muds it+ goodresults

%. Bo s,ecial ,ro,erties necessary

3. Batural or s,ecial emulsifying agents +old oil in tig+t sus,ension aftermi-ing

8. Oils used are6

=a> Crude oils

=b> Diesel

=c> Any oil it+ an A< gravity beteen % and

. Oil content in mud may be 1 to 8

'. Advantages are6

=a> 2ery stable ,ro,erties

=b> #asily maintained

=c> ?o filtration and t+in filter ca7e

=d> Faster ,enetration rates

=e> )educes don&+ole friction

;. !ajor objection is t+at t+e oil in t+e mud may mas7 any oil from t+e

formationsIn&i'i$ed Muds

1. !uds it+ in+ibited filtrates

%. ?arge amounts of dissolved salts added to t+e mud

3. ig+ , usually necessary for best results

8. Designed to reduce t+e amount of formation selling caused by filtrate& in+ibit clay +ydration

Drilling Fluids (


9/20

. Disadvantages

=a> Beed s,eciali*ed electric logs

=b> )e$uires muc+ s,ecial attention

=c> ?o mud eig+ts cannot be maintained it+out oil

=d> ard to increase viscosity

=e> Salt destroys natural filter ca7e building ,ro,erties of clays

G(psu" Base Muds

1. A s,eciali*ed in+ibited mud

=a> Contained large amounts of calcium sulfate

=b> Add % lb:bbl gy,sum to mud system=c> Filtration controlled by organic colloids

%. Advantages

=a> !ud is stable

=b> #conomical to maintain

=c> Filtrate does not +ydrate clays

=d> ig+ gel strengt+

3. Disadvantages

=a> Fine abrasives remain in mud

=b> )etains gas in mud

Oil Based Muds

1. Oil instead of ater used as t+e dis,ersant

%. Additives must be oil soluble

3. enerally ,re&mi-ed and ta7en to t+e ellsite

8. 4o increase aniline value5 blon as,+alt and unsla7ed lime may beadded

. Advantages

=a> @ill not +ydrate clays

=b> ood lubricating ,ro,erties

=c> Bormally +ig+er drill rates

'. Disadvantages

=a> #-,ensiveE

=b> Dirty to or7 it+

Drilling Fluids 9


10/20

=c> )e$uires s,ecial electric logs

=d> 2iscosity varies it+ tem,erature

Inverted Emulsions

1. @ater in oil emulsion. Oil largest com,onent5 t+en ater added.

Order of addition is im,ortant

%. ave some of t+e advantages of oil mud5 but c+ea,er.

Some+at less stable

Sal$ %a$er Muds

1. Can be used eit+er com,letion

%. @eig+t can vary u, to 1 lb:gal +en saturated

3. Bo filter ca7e building ,ro,erties5 easily lost to ,orous formationsSili#a$e Muds

1. Com,osed of sodium silicate and saturated salt ater

%. as a ,ic7ling effect on s+ales +ic+ ,revents +eaving or sloug+ing

3. @ill be 1% lb:gal or +ig+er

8. Corrosive5 e-,ensive and gives ,oor electric log results

L) Slids Muds

1. ee,s amounts of clays in t+e mud at a minimum5 +ic+ ,romotesfaster and safer drilling

%. 4+ree ays to remove solids from mud

=a> ater dilution

=b> centrifuging

=c> circulate t+roug+ large surface area ,its

3. @+en clays are removed5 a minimum of viscosity controlc+emicals areneeded

8. @+en viscosity and gel strengt+ become too lo5 clay solids arere,laced by organic or sus,ended material & ,olymers

. Ot+er advantages=a> ood for drilling it+ large ,um,s and +ig+ mud volumes

=b> Alays give faster drilling

'. roblems

=a> #-cessive dilution a ,roblem

=b> Can become e-,ensive

Drilling Fluids 1


11/20

DRILLING FLUID CL*SSIFIC*TION S+STEMS

Nn-Dispersed S(s$e"

4+is mud system consists of s,ud muds5 /natural0 muds5 and ot+er lig+tlytreated systems. enerally used in t+e s+alloer ,ortions of a ell.

Dispersed Mud S(s$e"s

4+ese mud systems are /dis,ersed0 it+ deflocculants and filtrate reducers.Bormally used on dee,er ells or +ere ,roblems it+ viscosity occur. 4+emain dis,ersed mud is a /lignosulfonate0 system5 t+oug+ ot+er ,roducts areused. ?ignite and ot+er c+emicals are added to maintain s,ecific mud,ro,erties.

Cal#iu"-Trea$ed Mud S(s$e"s

4+is mud system uses calcium and magnesium to in+ibit t+e +ydration offormation clays:s+ales. ydrated lime5 gy,sum and calcium c+loride are t+emain com,onents of t+is ty,e of system.

,l("er Mud S(s$e"s

olymers are long&c+ained5 +ig+ molecular&eig+t com,ounds5 +ic+ areused to increase t+e viscosity5 flocculate clays5 reduce filtrate and stabili*e t+ebore+ole. "io&,olymers and cross&lin7ed ,olymers5 +ic+ +ave good s+ear&t+inning ,ro,erties5 are also used.

L) Slids Mud S(s$e"4+is ty,e of mud system controls t+e solids content and ty,e. 4otal solidss+ould not be +ig+er t+an ' to 1. Clay content s+ould not be greater t+an3. Drilled solids to bentonite ratio s+ould be less t+an %61.

Sa$ura$ed Sal$ Mud S(s$e"s

A saturated salt system ill +ave a c+loride content of 1(95 ,,m.


12/20

*ir Mis$ Fa"-Based Mud S(s$e"s

4+ese /loer t+an +ydrostatic ,ressure0 systems are of four ty,es6 1> dry air

or gas is injected into t+e bore+ole to remove cuttings and can be used untila,,reciable amounts of ater are encountered5 %> mist drilling is t+en used5+ic+ involves injecting a foaming agent into t+e air stream5 3> foam drilling isused +en large amounts of ater is encountered5 +ic+ uses c+emicaldetergents and ,olymers to form t+e foam5 and 8> aerated fluids is a mudsystem injected it+ air to reduce t+e +ydrostatic ,ressure.

%rk.er Mud S(s$e"s

Also called com,letion fluids5 t+ese are s,eciali*ed systems designed to 1>minimi*e formation damage5 %> be com,atible it+ acidi*ing and fracturingfluids5 and 3> reduce clay:s+ale +ydration. 4+ey are usually +ig+ly treated

brines and blended salt fluids.

DRILLING FLUID *DDITIVES

!any substances5 bot+ reactive and inert5 are added to drilling fluids to,erform s,eciali*ed functions. 4+e most common functions are6

*lkalini$( and p/ Cn$rl

Designed to control t+e degree of acidity or al7alinity of t+e drilling fluid.

!ost common are lime5 caustic soda and bicarbonate of soda.

Ba#$eri#ides

Used to reduce t+e bacteria count. araformalde+yde5 caustic soda5 lime andstarc+ ,reservatives are t+e most common.

Cal#iu" Redu#ers

4+ese are used to ,revent5 reduce and overcome t+e contamination effects ofcalcium sulfates =an+ydrite and gy,sum>. 4+e most common are caustic soda5soda as+5 bicarbonate of soda and certain ,oly,+os,+ates.

Crrsin In&i'i$rs

Used to control t+e effects of o-ygen and +ydrogen sulfide corrosion.

ydrated lime and amine salts are often added to c+ec7 t+is ty,e of corrosion.Oil&based muds +ave e-cellent corrosion in+ibition ,ro,erties.

De!a"ers

4+ese are used to reduce t+e foaming action in salt and saturated saltatermud systems5 by reducing t+e surface tension.

Drilling Fluids 1%


13/20

E"ulsi!iers

Added to a mud system to create a +omogeneous mi-ture of to li$uids =oil

and ater>. 4+e most common are modified lignosulfonates5 fatty acids andamine derivatives.

Fil$ra$e Redu#ers

4+ese are used to reduce t+e amount of ater lost to t+e formations. 4+emost common are bentonite clays5 C!C =sodium carbo-ymet+ylcellulose> and,re&gelatini*ed starc+.

Fl##ulan$s

4+ese are used to cause t+e colloidal ,articles in sus,ension to form intobunc+es5 causing solids to settle out. 4+e most common are salt5 +ydrated

lime5 gy,sum and sodium tetra,+os,+ates.

Fa"ing *gen$s

4+ey are most commonly used in air drilling o,erations. 4+ey act as surface&ants5 to foam in t+e ,resence of ater.

Ls$ Cir#ula$in Ma$erials

4+ese inert solids are used to ,lug large o,enings in t+e formations5 to,revent t+e loss of +ole drilling fluid. But ,lug =nut s+ells>5 and mica fla7esare commonly used.

Lu'ri#an$s4+ese are used to reduce tor$ue at t+e bit by reducing t+e coefficient offriction. Certain oils and soa,s are commonly used.

,ipe-Freeing *gen$s

Used as s,otting fluids in areas of stuc7 ,i,e to reduce friction5 increaselubricity and in+ibit formation +ydration. Commonly used are oils5 detergents5surfactants and soa,s.

S&ale-Cn$rl In&i'i$rs

4+ese are used to control t+e +ydration5 caving and disintegration of clay:s+ale formations. Commonly used are gy,sum5 sodium silicate and calciumlignosulfonates.

Sur!a#$an$s

4+ese are used to reduce t+e interfacial tension beteen contacting surfaces=oil:ater5 ater:solids5 ater:air5 etc.>.

Drilling Fluids 13


14/20

%eig&$ing *gen$s

4+ey are used to ,rovide a eig+ted fluid +ig+er t+an t+e fluids s,ecific

gravity.!aterials are barite5 +ematite5 calcium carbonate and galena.

M*TERI*L B*L*NCE E0U*TIONS

!aterial balance e$uations are used for calculating volumes and densities+en to or more insoluble materials are mi-ed toget+er.

4+e !aterial "alance #$uation is6

21@1 G 2%@% ..... H 2F@F IIIIIIIIIIIIIIIIIIIII.I=1>

+ere6 21 G 2% ..... H 2F IIIIIIIIIIIIIIIIIIIII..I=%>

+ere6 21 H 2olume of first material to be mi-ed toget+er@1 H Density of first material

2% H 2olume of second material to be mi-ed toget+er

@% H Density of second material

2F H 4otal or sum of all volumes mi-ed toget+er

@F H Density of total mi-ture. ro,ortional average of all volumesmi-ed toget+er

4+e most commonly used variables in material balance e$uations are6

Bari$e1. @eig+t of a barrel of barite ="aSO8> s.g. H 8.% g:cc

8% gal:bbl - (.33 lb:gal - 8.% H 18; lb:bbl

J since barite comes in 1 lb sac7s5 one barrel contains 18.; sac7s

%. @eig+t of a gallon of barite

(.33 lb:gal - 8.% H 38.9 lb:gal

/e"a$i$e

1. @eig+t of a barrel of +ematite =Fe%O3> s.g. H . g:cc

8% gal:bbl - (.33 lb:gal - . H 1;89 lb:bbl%. @eig+t of a gallon of +ematite

(.33 lb:gal - . H 81.' lb:gal

Lig&$ Oil

1. #-am,le & =81K A< ravity> s.g. H .(% g:cc

%. @eig+t of a gallon of oil

(.33 lb:gal - .(% H '.( lb:gal

Drilling Fluids 18


15/20

E1a"ple ,r'le" 23

Calculate +o many sac7s of barite are re$uired to increase t+e density of an

( barrel mud system from 1%.; lb:gal to 18. lb:gal.Slu$in 23

Using6 21@1 G 2%@% H 2F@F

+ere6 21 H ( bbls

@1 H 1%.; lb:gal

2% H un7non volume of barite

@% H 38.9 lb:gal =density of barite>

2F H 21 G 2% =or ( G 2% >

@F H 18. lb:gal

t+erefore6 (=1%.;> G 2%=38.9> H =( G 2%> - 18.

151' G 38.92% H 115' G 18.2%

%.82% H 188

2% H ;.' bbls of barite

;.' bbls - 18.; s7:bbl H 13( sac7s of barite

E1a"ple ,r'le" 46

Calculate +o muc+ ater and barite are re$uired to ma7e ( barrels of a1. lb:gal ater&based drilling mud.

Slu$in

Using6 21@1 G 2%@% H 2F@F

+ere6 21 H un7non volume of ater

@1 H (.33 lb:gal

2% H un7non volume of barite or =( & 21>

@% H 38.9 lb:gal

2F H ( bbls

@F H 1. lb:gal

4+erefore6 21=(.33> G =( & 21>38.9 H (=1.>

(.3321 G %;9% & 38.921 H (8

&%'.;21 H &19%

21 H ;3 bbls of ater

2% H ( bbls & ;3 bbls H ' bbls of barite L 18.; s7:bbl or 9' sac7s

Drilling Fluids 1


16/20

OIL-B*SED DRILLING FLUIDS

4+ese fluids5 because of t+eir s,ecial nature of being a mi-ture of to

immiscible li$uids =oil and ater>5 re$uire s,ecial treatments and testing,rocedures.

Dispersed ,&ase34+e li$uid ,resents in t+e form of finely divided dro,lets.

Cn$inuus ,&ase34+e li$uid ,resents in t+e form of t+e matri- in +ic+ t+edro,lets are sus,ended.

4o 7ee, t+ese li$uids stabili*ed =i.e. to 7ee, t+e dis,ersed ,+ase fromcoalescing and settling out of t+e mi-ture>5 an emulsifier is added to form aninterfacial film around t+e dis,ersed ,+ase +ic+ causes t+em to re,el eac+ot+er5 so t+ey remain dis,ersed.

4+e effectiveness of an emulsifier de,ends on t+e al7alinity and electrolytes=c+loride content> of t+e ater ,+ase5 and t+e tem,erature of t+e drilling fluid.

Ele#$ri#al S$a'ili$(

4+e electrical stability =#.S.> of an oil&based drilling fluid is t+e stability of t+eemulsions of ater in oil5 or t+e amount of current re$uired to brea7 t+eemulsifier don and allo t+e saline ater to coalesce.

1. An electrical ,robe is inserted into t+e drilling fluid and t+e voltageincreased until t+e emulsion brea7s don

=c> t+e measure of emulsion brea7don is indicated by current flo

=d> relative stability is recorded as t+e amount of voltage at t+ebrea7don ,oint

%. #.S. is recorded as t+e voltage reading and tem,erature of t+e drilling fluidsam,le

=a> adding emulsifier ill raise t+e #.S. readings

=b> normal /fres+0 mud is about 3 or +ig+er

=c> during drilling5 t+e #.S. can increase to ( or +ig+er

Oil3 %a$er Ra$i

T&e Oil3 @ater )atio is defined as t+e ,ercent oil in t+e li$uid ,+ase and t+e,ercent ater in t+e li$uid ,+ase. 4+e ,ercentages can be determined from aretort analysis of t+e drilling fluid.

E1a"ple ,r'le" 5

Determine t+e oil6 ater ratio from t+e folloing retort analysis6

Oil H 8 ater H 3' solids H 1

4+e oil6 ater ratio is '68

Drilling Fluids 1'


17/20

4o c+ange t+e oil6 ater ratio re$uires t+e additions of oil to increase t+e ratio5and ater to decrease t+e ratio. For e-am,le5 t+e oil re$uired to increase t+e

oil6 ater ratio can be calculated using6+ere6 2i H initial of ater by volume =>

2f H final of ater in li$uid ,+ase =>

2t H initial total li$uid volume =>

2m H total mud volume =bbls>

4+e ater re$uired to reduce t+e oil6 ater ratio can be calculated using6

+ere6 2io H initial of oil by volume =>

2fo H final of oil in li$uid ,+ase

*niline ,in$

Anot+er common term used +en dealing it+ oil&based drilling fluids is t+eaniline ,oint of t+at fluid. 4+e aniline ,oint is t+e tem,erature belo +ic+ anoil containing by volume aniline =C'&B%> becomes cloudy. 4+e solvent,oers for rubber are related to t+e solvent ,oer for aniline. Oils +aving ananiline ,oint above 18oF are considered acce,table to use

Drilling Fluids 1;


18/20

DRILLING FLUID ECONOMICS

Ta'le 23 T(pi#al C"psi$in6Cs$s 7 Un )eig&$ed Drilling Fluid 8Barrels r

punds ne#essar( $ "i1 ne 'arrel9

Com,onent 2olume Unit Cost=M>

Com,onent Cost=M>

L) Cllid Oil-Based Drilling Fluid

Diesel Oil .( bbl l8%. 33.'

#mulsifier:@ettingAgent

'. 1. 9.

@ater .18 bbl & &

el . lbs 1.% '.

Calcium C+loride %. lbs .% 8.

?ime 3. lbs .1 .3

4otal Cost %.9

Fres&-%a$er Dispersed Drilling Fluid

"entonite %. lbs .; 1.;

C+rome ?ignosulfonate '. lbs . 3.?ignite 8.lbs .3 1.%

Caustic Soda 3.lbs .8 1.%

@ater 1. bbl & &

4otal Cost =1 bbl> ;.1

:Cl ,l("er Drilling Fluid

"entonite =,re&mi-ed :%O>

. lbs .; .3

C+rome ?ignosulfonate 1. lbs . .

Caustic Soda .3 lbs .8 .1%

otassium C+loride 3. lbs .% ;.

olyanionic Cellulose %. lbs 3. '.

otassium ydro-ide .3 lbs .( .%8

4otal Cost =1 bbl> 18.%1

Drilling Fluids 1(


19/20

Ta'le 43 T(pi#al C"psi$in6Cs$s - 2;9

L) Cllid Oil-Based Drilling FluidDiesel Oil . bbl 8%. %3.1#mulsifier:@ettingAgent

(. lbs 1. 1%.

@ater .9 bbl & &el 8. lbs 1.% 8.(Calcium C+loride 1. lbs .% 3.

?ime 3. lbs .1 .3"arite . lbs .; 3.4otal Cost =1 bbl> ;(.%

Fres&-%a$er Dispersed Drilling Fluid"entonite %. lbs .; 1.8C+rome?ignosulfonate

9. lbs . 8.

?ignite '. lbs .3 1.(Caustic Soda 8. lbs .8 1.'"arite 8. lbs .; 31.

@ater 1.bbl & &4otal Cost =1 bbl> 8.(:Cl ,l("er Drilling Fluid

"entonite =,re&mi-ed: %O>

. lbs .; .3

C+rome?ignosulfonate

1. lbs . .

Caustic Soda .3 lbs .8 .1%otassium C+loride %8. lbs .% 8.(olyinosinic Cellulose 3. lbs 3. 9.!odified Starc+ . lbs 1. .

otassium ydro-ide .3 lbs .( .%8"arite 8. lbs .; %(.4otal Cost =1 bbl> 83.1

Drilling Cndi$ins

Drilling Fluids 19


20/20

ig+ Angle ole =N3> - - - - - - - -

2ery )eactive S+ales - - - - - - - - - - -

Stic7ing roblems - - - - - - - -

?ost Circulation - - - - - -

!ud @eig+ts=N1',,g>

- - - - - - - -

4em,eratures=N3%F>

- - - - -

as ydrates - - -

)ecommended !ud4y,e

Oil&"ased 1 1 1 1 % 1 1

?ignosulfonate 1 % 1 % %

olymer % 1 % 3 % 1 3

otassium ?ime 1 1 1 3 3 %

4o use t+is c+art6 are6

=1> oil&base5

=%> ,olymer and

=3> ,otassium lime

13- Drilling Fluid Final

Documents

Transcript of 13- Drilling Fluid Final