6 inhibiting water based muds

8/12/2019 6 Inhibiting Water Based Muds

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1Agip KCO Well Area Operations

Drilling Supervisors Training Course Drilling Muds RPW2021A

INHIBITING WATER

BASED MUDS





Fluids classification :

• Calcium base

• Salt base

• Potassium base

INTRODUCTION





CALCIUM BASED MUD

• Lime Muds –Ca(OH)2 FW/SW-LI

• Gyp Muds -CaSO4.2H2O FW/SW-GY

Calcium absorption from clays





Reduction water hydration for sodium clay

during base exchange with calcium.

CALCIUM BASED MUD





Effect of solids concentration

on viscosity with calcium additions.

CALCIUM BASED MUD





Line A - Soluble calcium vs. lime

concentration;

Line B - Soluble calcium of 4 lb/bbl of l ime

added to caustic solutions.

CALCIUM BASED MUD





Solubil ity of calcium vs. chlor ides.

CALCIUM BASED MUDS





LIME BASED MUD

Description and application

• This system is used to drill in reactive shale formation, even at high temperature

• It is a dispersed, lignosulfonate base fluid where lime is apporting source of Ca++.

• Two basic formulations: low lime (5-8 kg/m3 – 1.75 – 2.8 ppb excess of lime) and high

lime content (20 kg/m3 – 7 ppb excess of lime)

• The tolerance to high solids is acceptable

• It is possible to weight up to over 2.1 kg/l (17.5 ppg)

• Low cost





LIME BASED MUDS

Limitations

• The system needs more dilution than other inhibitive systems.

• The high value of the pH (up to 12) reduces the inhibitive action of the Ca++ due to

the dispersing action.

• At temperature over 120°C gelation problems may occur.





LIME MUD (FW/SW-LI)

15 - 259 - 154 - 9Pm

5 - 102 - 50.8 - 2PF

High LimeIntermediateLow Lime

Lime muds classification versus alkalinity values





Filtration Control0.5 - 3PAC

Filtration Control0,6 – 1,2*(Starch)

Filtration Control0,5 – 1,2Lignite

pH Controlfor pH 10.5 - 12.5Soda or caustic potash

Inhibitor, alkalinity control5 - 30Lime Ca(OH)2

Deflocculant0,5- 1,5Lignosulfonate

Viscosity, filtrate control60 - 80Bentonite

FunctionConcentration, kg/mc Additive

Lime Muds main additives

LIME MUD (FW/SW-LI)

* Antifermentant treatment needed





6 - 1215 - 4512.0 -12.55 - 1012 - 180- 20 - 13 - 515 - 18HighLime

1,20

6 - 123 - 610.5 -12.51 - 25 - 100 - 20 - 13 – 515 - 18

Low

Lime

1,20

API

Filtrate

(cm3/3

0 min)

Eccess

Lime

(Kg/m3)

pHP

F cc

H2SO4

n/50

PM cc

H2SO4

n/50

Gels

10 sec/10

min

(gr/100 cm2)

Yield

Point

(gr/100

cm2)

Plastic

Viscosit

y

(cPs)

Density

(Kg/lt))

Typical Properties of a Low and High Lime Mud

LIME MUD (FW/SW-LI)





7.04 11,3

5.03 7,8

3.02 5,6

1.01 2,8

PF, cm3 H2SO4 - N/50NaOH, lb/bbl Kg/mc

Filtrate alkalinity due to Caustic Soda additions (NaOH)

LIME MUD (FW/SW-LI)





2 – 5 5 - 15Thinning Agent

4 – 8 10 – 20Lime

2 – 3 5 – 8Soda/ Caustic potash

Concentration,

lb/bbl Kg/mc Additive

Treatment Ranges for Lime Mud Conversions

LIME MUD (FW/SW-LI)





Add lime for PM control and KOH for

PF.control. Check solids content

optimal conditions ( Low)

MF, Gel10-min increase .

PM, pH decrease. If the CO2 inlet is

continuous, normal treatments with

lime cause a thin solids increase

(CaCO3).

Carbonates/CO2

Increase density (if the level

increases), to dilute with fresh water.

Add fluidizing and caustic soda to

control the rheology then treat with

starch or PAC for the filtrate control. If

salt presence is high, transform the

system saturated with salt. Or replace

with oil based mud.

Chlorides, Visc.Marsh , yield point,

gel 10” / 10’ , filtrate increase.

PM, PF, pH decrease.

Salt/Salt water

More dilution. Improve the solids

removal. Centrifuges use.

Increase in solids content in retort

test.

Increase in PV, Gels, MBT.

Increase of solids in the mud

TreatmentsIndicatorsContaminants

Lime Muds contaminants treatments

LIME MUD (FW/SW-LI)





LIME MUD (FW/SW-LI)

Reduce Low Gravity solids. Add

lignosulfonate if bottomhole

temperature is <300°F (150

°C).

Add polymeric deflocculant for

high temperature, for values

higher than 150°C.

Pressure peaks after round trip.

Bottom cushion very viscous. High

viscosity in the mud at the flow line

Gelation due to high

temperature

Add a non toxic antifoam.

Detect the foaming causes and

remove them

Foam in the tanks. Trapped air .

Decrease pressure pumps if

possible

Foam

Shipping documents and

specifications control.

Organize sampling and analysis.

Cooperation with the Supplier

Packaging variations. Treatment

quantities increasing. Mud

properties anomalous state.

Low quality products






GYPSUM MUD (FW-GY)

Weighting MaterialProgrammed DensityBarite

Viscosity, Filtrate control0.7 – 4,5PAC

Filtrate Control5 - 18Starch

Deflocculant5 - 10Tannin Sulphonated

InhibitionpH 9,5 - 11Caustic Potash

Alkalinity control,Inhib.IpH 9.5 - 11.0Caustic Soda

Inhibition, alkalinity control10 - 25Gypsum

Deflocculant10 - 25Lignosulfonate

Viscosity, filtrate control60 - 70Bentonite

FunctionConcentration,Kg/mc Additives

Main Gypsum Mud additives





6 - 8200-60011.0 -

12.02 - 330- 401- 7,50 -2,51- 7,515 - 201,44

8 - 12600-12009.5 - 11.00.2 - 2.730- 404- 61-23– 512 - 151,08

API

Filtrate

(cm3/30

min)

Ca++

(mg/L)pHPF

Exceeding

Gypsum

(Kg/mc)

Gels

10 sec/10 min

(gr100 cm2

Yield

Point

(gr 100

cm2)

Plastic

Viscosity

(cPs)

Density

(Kg/lt)

Gypsum mud typical characteristics

GYPSUM MUD (FW-GY)





It stabilizes the hole (regular section)

It resists to contaminations: Cement,

Anhydrite and Salt (Up to50000mg/lt Cl-)

It inhibits clay sands and clays hydration.

Weighting facility up to 2,16 Kg/lt.

Gelation phenomena with temperature

higher than 300°F (150°c)Solids content tolerance.

High pressure peaks (pressure loss) during

conversion can cause “Hole Damages”.Low Viscosity and Gel strengths.

Disadvantages Advantages

Advantages/Disadvantages of Gyp Mud

GYPSUM MUD (FW-GY)





Add lime for PM and KOH for PF

control. Keep solids control to the

lowest possible level

Increase MF,Gel 10-min .

PM, pH decrease. To control the CO2

need Ca (OH)2 treatment- that causes

thin solids increase (CaCO3)

Carbonates/CO2 (no

problem for lime

muds.)

Increase the density if water flows

from well. Treat with deflocculantand soda for rheology, starch or

PAC for the filtrate. Transform the

mud saturated with salt or oil

base mud, in presence of salt

dome.

Chlorides, viscosity, yield point, Gel

10”/10’ and filtrate increase.PM, PF, pH decrease

Salt/Salt Water

Higher dilution, improve solids

discard, use the centrifuges to

treat the mud

Values at Mud Still, PV,gel at

10-minute , MBT.

High content of low

gravity solid

TreatmentsIndicatorsContaminant

Contaminant Treating of Gyp Muds

GYPSUM MUD (FW-GY)





GYPSUM MUD (FW-GY)

Reduce low gravity solids, treat

with lignosulfonate if

BHT<300°F Treat with

polymeric deflocculant with

temperature higher than 300°F

(150°C).

Pressure peaks at the pump (when

the circulation restarts) after the

round trip.

Very viscous bottom cushions and

high viscosity mud at the flow line

Temperature gelation

Treat with non toxic antifoam.Identify the foam origin and

operate.

Foam in the tanks, air incorporatedin the mud, irregular pump pressureFoam

Supplier documents.

Sample and analyse.

Collaborate with the Supplier

and detect the trouble (do not

change the supplier)

Different packing, minor product

performance. Mud characteristics

not conform to the programmed

values







SALT BASED MUDS

• Mainly used to drill salt formations. Sometimes also used as inhibitive fluid in shale

formations. It’s better when saturated

• It is possible to use the system with suitable viscosity as work-over fluid

• Lower cost referred to other competitor system

• The basic product, (NaCl) is readily available





SALT BASED MUDS

10,000-25,000Brackish Water

25,000-35,000Sea Water

315,000Salt saturated (NaCl)

NaCl, mg/LSalt Muds Classification





Salt saturated mud

The pH control, changes widely and it is not a fundamental function pf the system. Manylow Solids Mud with starch are formulated without caustic soda. In other areas the pH=11

– 11,5 is maintained, with NaOH addition. The S.S. mud, needs a major quantity of soda

to keep a high PH. To maintain the pH = 11 – 11,5 gives several advantages :

• More efficient fluidizing

• Reduced Corrosion

• To reduce the filtrate, minor quantities of additives, are needed when the

solubility from Ca++ and Mg++ is reduced.

• Minimizes foaming tendency

• Mud is generally more stable

SALT BASED MUDS





Inhibition,

Weighting350Salt (NaCl)

Filtrate control,Viscosity0.7 - 4.2PAC

Ca++ Removal3 - 8Soda Ash (Na2CO3)

Alkalinity controlpH 9.0 - 11.0Caustic Soda

Filtrate control10 - 20STARCH

Viscosity, Filtrate control30 - 70Pre-hydrated Bentonite

FunctionConcentration, Kg/mc Additive

Principal Addit ives of Salt Saturated Muds

SALT BASED MUDS





8.5-9.

5

pH

6 - 815-18/30-363-5/6-1010-14/20-2845-502.1-17.5

8 - 126-8/12-162-4/4-84-6/8-128 - 121.26 – 10.5

API

Filtrate

(cm3/30 min)

Gels

10 sec/10min

(gr/100cm2

)(lbs/100 ft2)

Yield

Point

(gr/100 cm2

)(lbs/100 ft2)

Plastic

Viscosity

(cPs)

Density

(Kg/lt)

(ppg)

Typical Properties of Salt Saturated Muds

SALT BASED MUDS





Stabilizing action on-open hole.

Temperature max limit = 280°F (140°C).Good hole cleaning (cuttings transport).

Corrosive, with salinity lower than saturationLow solids content. The dissolved salt

helps density.

Foaming and air entrap tendenceContaminations resistant: cement,

anhydrite, salt and salt water.

Filtrate control more difficult (starches or

polymers efficiency)Inhibiting (clays)


Advantages/Disadvantages of Saturated salt Muds

SALT BASED MUDS





Sea Water Based Mud Advantages and Disadvantages

Pre-hydrated bentonite is requiredContaminants negative aspects; anhydrite,

cement, salt and layer salt water

Difficult to control filtrationReduced fresh water consumptions.

Increasing of the quantity of additives used

because of lower performanceInhibiting Material (clay layer)


Advantages/Disadvantages of Saltwater Muds

SALT BASED MUDS





Problems and Contaminations – Sea Water Muds

Contaminations are more evident compared to S.S. mud. The sea water mud has higher

quantities of additives. The salinity and hardness range affect the fluid performances

Increase density in case of

inlet from formation water.

Treat with fluidizing to controlthe rheology. Control filtrated

with starch or Pac. Add

caustic soda to repristinate

correct PH

YP, Filtrate and chlorides

increase.

In case of formation water, loss of

density and PH decrease

Salt /Salt Water

Massive dilutions, use ofcentrifuges and other

equipment to remove solids.

Increase % solids , PV, YP, gel,viscous mud cushions from

bottomhole to surface

High Solid Contents


Contaminant Treating of Saltwater Muds

SALT BASED MUDS





SALT BASED MUDS

Know the production

methodology.

Sample and analyse the product

Increase the quantity of treating.

Different packagingLow quality product

Add sodium bicarbonate or

SAPP. Dilute with water (fresh or

sea). Treat with fluidizing, starch

or PAC (Rheology and filtrate

control)

PV, YP, pH, PM, PF, gel and filtrate

increase. Ca++ increase.Cement


Contaminant Treating of Saltwater Muds

Increase pH at 10.7 or more to

convert the bicarbonate in

carbonate, treat with lime or

gypsum to remove carbonates.

Increase gels, YP. Rheology not

correct. Bottom cushion with high

viscosity.

Carbonates





Brackish-Water Muds

In many areas, for economical reasons or for fresh water shortage, Brackish waters

are often used to prepare mud. They have a salinity (NaCl) between 10000 and

15000 mg/lt. These areas are near the sea a/o in marshy zones.

Main additives (Brackish-Water Muds)

They are essentially the same additives of the sea water mud; they have lower

salinity. Because of brackish-water (bacterium and organic products), the use of

chemicals is always high to reduce the bacterium degradation

SALT BASED MUDS





HP/HT Filtrate control.6 - 10Lignite

Deflocculant9 – 18Lignosulfonate

Filtrate control1,5 – 3PAC

Filtrate control9 – 18Starch

Pf corrosion control1,5 – 4,5Soda / Caustic potash

Viscosity and Filtrate,

Control40 - 70Pre-hydrated bentonite

FunctionConcentration, Kg/mc Additives

Principal Additives of Brackish Water Muds

SALT BASED MUDS





6 - 810,000 -25,00010.5 - 113 – 5

6 –10

2 – 3

4 – 6

6 – 8

12 – 16221,45

6 - 1010,000 -25,00010.5 –112 – 5

4-10

1 – 2

2 – 4

4 – 5

8 – 10161,10

API

Filtrate

(cm3/30

min)

Chlorides

mg/LpH

Gels

10 sec/10min

(gr/100cm2)

Lbs/100ft2

Yield

Point

(gr/100

cm2

)lbs/100ft2

Plastic

Viscosity

(cPs)

Density

(Kg/lt)

Typical Properties of Brackish-Water Muds

SALT BASED MUDS





Pre-hydrated bentonite (in fresh water) is

required

Reduced fresh water consumption

(Brackish water is used).

Use of chemical products increasing,

(because of minor efficiency)Give moderate inhibition degree


Advantages/Disadvantages of Brackish-WaterMuds

SALT BASED MUDS





Problems and Muds Contaminations - Brackish-Water Muds

Contaminations and problems are the same of the sea water system

SALT BASED MUDS





There are three potassium based muds:

• KCl-Polimers (KCl-PHPA)

• KOH-Lignite

• KOH-Lime

POTASSIUM MUDS – (FW/SW-KC)





KCl-Polimers (KCl-PHPA) =FW/SW-KC

Filtrate control HP/HT5 - 10Lignite

Fluidifizing8 - 16-Lignosolfonate

Filtrate control1.5 – 3PAC

Filtrate control8 – 16Starch

Gives ions K+ and controls

alkalinity0.7 – 2Caustic Potash

Inhibiting source K+15 - 170Potassium Chloride

Control Visc. and filtrate15 - 45Pre-hydrated Bentonite

FunctionConcentration,Kg/mc Additive

Principal Additives of KCL-Polymer Muds






1 - 32 - 51 - 33 - 430 - 451,92-2,16

2 – 42 – 61 – 33 – 825 - 451,68–1,92

2 – 42 – 81 – 33 – 820 – 401,44–1,68

3 – 62 – 81 – 43 – 815 – 351,32–1,44

5 – 84 – 81 – 45 – 1015 – 251,20–1,32

10 - 124 - 103 – 45 – 1012 – 251,10-1,20

APIFiltrate

(cm3/30 min)

Gels10 sec/10min

(gr/100cm2)

YieldPoint

(gr/100cm2)

PlasticViscosity

(cPs)

Density(Kg/lt)

Typical Properties of KCL-Polymer Muds






2,810809--31,5751,4206872,16

2,88309--31,5801,4287181,92

2,867012--42,2851,4367501,68

2,8350124--2,8900,7408121,44

2,80124--2,81000,7409371,20

PHPA

ActiveBarite

Reg

StarchPAC

Gum

LVXanthanKCl

Caustic

PotashBentonite

Water

(lt)

Density

KG/Lt

CONCENTRATION , Kg/mc

Typical Material Concentrations for KCl-Polymer Muds






Product documentation

Supplier quality history. Sample

and analyse.

The product packaging changes.

Higher quantity of the product usedLow-quality products

Minor dilution. To treat with

bicarbonate a/o SAPP. When

rheology becomes stable treat

with starch or PAC to reduce

filtrate.

Increase: PM, P

F, pH, YP, Filtrate, and

Marsh viscosityCement

Large dilutions. Use centrifuges

and improve the efficiency of

solids control equipment .

Increase: solids, PV, YP, gels. Viscous

bottom cushions after the round tripHigh % solids


Contaminant Treating of Brackish-Water Muds






Carry out GGT analysis. RaisepH>10,7 with KOH.

Add lime and guarantee the value

of the solids within acceptable

limits.

Increase: MF, YP, gels.Decrease: pH, PM, PF. Viscous bottom

cushions and also high viscosity to the

mud comes from flow Line

Carbonates

Treat with SAPP, soda ash or

potassium carbonate. When

necessary, treat with fluidizing

Increase: Ca++, YP, gels, filtrate.

Decrease: pH, PM, PF.Gypsum/ Anhydrite

Increase density if the well flows

salt water. Convert in a mud

saturated with salt

Increase:Chlorides, Marsh viscosity,

YP, Gels, Filtrate.Salt Water/salt


Contaminant Treating of Brackish-Water Muds






KOH-Lignite (system)

Weighting material

Add the amount needed

to reach a programmed

value of density

Barite

Viscosity and filtrate control1,5 – 3PAC/CMC

Alkalinity and K+ control1,5 – 4,5Caustic Potash

Fluidizing and filtrate control15 - 23Lignite

Viscosity and filtrate control.45 - 75Bentonite

FunctionsConcentrations, kg/mc Additives

Principal Additives of KOH-Lignite Muds






6 – 810.03 - 51 - 35 – 916 - 201,44

10 - 1210.02 – 41 – 24 - 612 - 141,08

API

Filtrate

(cm3/30 min)

pH

Gels

10 sec/10min

(gr/100cm2)

Yield Point

(gr/100 cm2)

Plastic

Viscosity

(cPs)

Density

Kg/l

Typical Properties of KOH-Lignite Muds






Thermic stability up to 400°F(240°C).

Simple. Limitated product numbers

Clay solids (L.G.) must be kept very lowEconomical. Control filtrate with lignite and

bentonite

Contaminants intolerance such as, salt,

Ca++, cement, carbonates and anhydriteInhibiting system


Advantages/Disadvantages of KOH-Lignite Muds






Production documents. Makesample and analysis. Pilot test

with good quality materials.

(comparison)

Increases treatment quantity.

(consumptions)Low quality product

Deflocculate with bicarbonate

a/o SAPP. Dilute with water.Increase PF to limit the Ca++.

Fluidify to reduce rheology.

Transform in FW-LI if

necessary.

Increases PM, P

F, pH, YP, gel and

filtrate.Cement

Dilute and use centrifuge,

improve solids removal.

Increases:solids, PV, YP, and gels.

Viscous bottom cushions. High

additives consumption

High solid contents


Contaminant Treating of KOH-Lignite Muds






Increase pH with KOH to reduce

Ca++. Treat with bicarbonate and

soda Ash.

Add fluidizing or convert in FW-

GY.

Change drilling speed (metres/hour) .

Increases: Ca++ , Decrease: pH, PM,

PF.

Anhydrite/Gypsum

Increase density, (Kill Flow)

Treat with water and fluidizing for

rheology control, then PAC/CMC

for filtrate. Convert in mud SS

when there’s much salt.

Well lows, viscosity, chlorides, YP,

filtrate increases. Density decreasesSalt Water/Salt




POTASSIUM MUDS (FW/SW KC)





Reduce L.G: E MBT solids.Use thermostable fluidizing.

Analysis for carbonate

contamination (GGT).

High pressure peaks at thepump to restart circulation after

breaks. Bottomhole viscous

cushions after trips.

Gelation for High

temperature

Carry out GGT analysis.

Raise the pH over 10,7 with

KOH. Add lime a/o gypsum

to settle carbonates (avoidovertreatments). Keep

drilled solids contents (L.G.)

within recommended limits

Increase: MF, YP, gels. False

rheological results. Decreases:

pH, PM, PF. Viscous bottomcushions after round trips, high

viscosity mud at the Flow line

Carbonates








4 - 63 – 62 - 38 – 1016 - 181,44

6 - 93 - 52 – 34 – 610 - 121,08

API

Filtrate

(cm3/30 min)

Gels

10 sec/10.min

(gr/100cm2)

Yield Point

(gr/100 m2

)

Plastic Visc.

(cPs)

Density

(Kg/l)

Typical Properties of KOH-Lime Muds

POTASSIUM MUDS– (FW/SW-KC)






Bentonite must be pre-hydrated

Gelation at high temperature

Complex, many additivesContaminations resistance : Anhydride,

Cement, Carbonates and salt.

Decreasing ROP in hard formationSolids Tolerance

Non dispersed fluidInhibiting (Ca++ e K+)


Advantages/Disadvantages of KOH-Lime Muds







Increase Kill Flow denisty.

Dilute with fresh water. Treat

with fluidizing and KOH for

rheology and then PAC or

starch for the filtrate. With

large quantities of salt,

convert it in saturated salt or

replace with oil base mud.

Increase: Chlorides, Viscosity, YP,

gel and filtrate. Decreases: PM, PF,

pH, and density (salt water).

Salt and salt water

Strong dilution, use

centrifuge and improve solids

removal.

Increase: % solids, PV, YP, Gel

10’-High solid contents


Contaminant Treating of KOH-Lime Muds







Supplier documents on

production mehtods and

quality control. Sample and

analyse through comparisonwith standard products as

well.

Package product changes.

Product quantity increasing, to

obtain the same results. Mudscharacteristics not reliable

Low quality

products

Add Ca(OH)2 for the PM e

and KOH for PF..

Check clay solids at the

planned range lower limit.

Increase: MF, gels10’, rheology

difficult to control. Decreases :

Pm,PH

Carbonates / CO2











Treat with non toxic anti-foam.

Detect the cause of the trouble

and remove it.

Presence of foam to the tank and

shaker

The mud incorporates/absorbs air,

pump pressure drop.

Foaming

Reduce L.G. solids.

Increase lignosulfonate

concentration if the temperature is

lower than 160°C. If the

temperature is higher, use hightemperature deflocculant.

Viscous bottom cushion after round trip.

Viscous mud at the flow line (not at the

sump pit).

Pressure peaks at the pump after abreak.

Temperature Gelation


POLYMERS FLUIDS





Weighting material Add the amount needed toreach a programmed value of

density

Barite

Filtrate control1.5 – 4.5PAC/CMC Regular

Calcium removal0.75 – 1.5 Ash Soda

AlkalinitypH 9.0 – 9.5Caustic Soda

Viscosity and Filtrate

control15 - 30Bentonite

FunctionConcentration Kg/mcMaterials

Low Solids PAC/CMC Muds: Main Additives

POLYMERS FLUIDS

POLYMERS FLUIDS





9.0 – 9,5< 200

6 - 8

< 20005 - 83 - 65 - 88 - 101,44

9.0 – 9.5< 20010 – 12< 20003 - 52 - 44 - 64 - 61,08

pHHardnes

s (mg/L)

API

Filtrate

(cm3/30 min)

Chlorides

mg/L

Gels

10 sec/10min

(gr/100cm2)

Yield

Point

(gr/10

0 cm2)

Plastic

Viscosity

(cPs)

Density

(Kg/lt)

Typical Properties of Low-Solids PAC/CMC Muds

POLYMERS FLUIDS

POLYMERS FLUIDS





To settle ions Ca++0,75 – 2,15 Ash Soda

Filtrate control0,75 – 1,5SPA

Solids encapsulation,

Borehole stability,

Viscosity control

2,85PHPA

Alkalinity ControlpH 9,0 – 9,5Soda /Caustic Potash

Filtrate and Viscosity

Control3 - 40Bentonite

FunctionConcentration Kg/ltMaterials

Principal Additives of Low Solids PHPA Muds

POLYMERS FLUIDS

Low Solids PHPA Muds (polyacrilamide partially hydrated)

POLYMERS FLUIDS





6 – 85 – 84 - 66 – 108 - 101,44

10 - 123 – 52 – 45 – 74 – 61,08

API

Filtrate

(cm3

/30 min)

Gels

10 sec/10min

(gr/100cm2

)

Yield

Point

(gr/100 cm2

)

Plastic

Viscosity

(cPs)

Density

(Kg/lt)

Typical Properties of Low-Solids PHPA Muds

POLYMERS FLUIDS

POLYMERS FLUIDS





Not very inhibiting.

Weighting difficulty

Contaminants sensible.

Carbonates contamination difficult to be treated

More corrosive than deflocculate system.

Filtrate control is expensiveIt doesn’t disperse solids (inhibited system).

They need higher dilutions compared to the

deflocculate system

Easily convertible in a deflocculated/dispersed

system

Solids increase is not tolerated.Easy maintenance

Low stabilit at temperatures.Good borehole cleaning (Transport Capacity)

Polymers absorption on clays is irreversiblePressure drop low values/ ECD

Limited useHigh ROP (m/hour) in hard formations


Advantages/Disadvantages of Non-Dispersed Polymer Muds

POLYMERS FLUIDS





Control (Ca++) contamination

with bicarbonate a/o SAPP or

Citric Acid

Dilute with fresh water.

Increase PF

in order to limit

the Ca++ solubility.

Deflocculant could be

necessary or convert mud

into lime

Marsh viscosity, pH, PM, PF, gels,

filtrate increasingCement

Higher dilution use the

centrifuges

To improve solids control

Increases: solids %, PV, YP, gels,

MBT. Viscous bottom cushions

after round trip.

High viscosity at the flow Line.

High SolidContents

TreatmentIndicatorsContaminant

Contaminant Treating of Non-Dispersed Polymer Muds

POLYMERS FLUIDS





Treat for Ca++ with ash soda,

Bicarbonate a/o SAPP. Add

fresh water. Deflocculanttreatment can be required.

Increase:Ca++, YP, Gels, and filtrate

Decrease: pH, Pm, Pf.Gypsum/Anhydrite

Increase density (if the well

flows). Dilute with fresh water to

reduce chlorides. Treat with

deflocculant for PAC

contamination and for thefiltrate control. If necessary

transform in SS. mud

Well flowing.

Increases: Marsh viscosity, YP, Gels,

Filtrate.

Surface water separation.Decreases: pH, P

M, P

F.density.

Salt water/Salt



POLYMERS FLUIDS





Documentation of the

productive process from

supplier.

Sample and analyze. Pilot test

comparison with reliable

products

Treatment quantities increasing.

Type of packaging changed.

Poor results with standard

treatments


Add lime for the Pm and KOH

for the Pf. Keep the content of

clayey solids to the lowest

possible value.

Increases: MF, gels 10’. Rheology

difficult to be checked. Dercreases:

PM, pH.

Carbonates / CO2

(Not very

problematic)



6 inhibiting water based muds

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