This document discusses various water-based mud systems used in drilling operations. It describes the basic systems commonly used like lignosulfonate systems and calcium treated systems. More complex systems are used as conditions change with increasing well depth, temperature and pressure. Factors that influence the choice of mud system include the application, geology of the formation, make-up water quality, drilling parameters, potential drilling problems, and rig equipment limitations. The document provides details on specific mud systems like potassium chloride PHPA mud, silicate mud and their components and applications.

2. Water Base Mud Systems
Many types of water-base systems.
Basic systems are usually converted to
complex systems as a well is deepened,
as wellbore temperatures and/or
pressures increase and formations
dictate.
More than one system is typically used
when drilling the same well.

3. Classification of Water Base Muds
Un-weighted clay water suspensions
Deflocculated, weighted clay-water
suspensions
Calcium treated, weighted deflocculated clay-water
suspensions
Salt water systems
HTHP Deflocculated Systems
Polymer Systems with/without salts
HTHP Polymer Systems
Cationic Systems

4. Factors Affecting Choice
Application:
Drilling surface interval
Drilling intermediate interval
Drilling production interval
Completion Method
Production Type

5. Factors Affecting Choice
Geology
Shale Type
Sand Type
– Permeability
Other Formation Types
– Carbonate Rock
 Limestone
 Dolomite
– Salts

6. Factors Affecting Choice
Make-Up Water
Type of water
Chloride concentration
Hardness (Calcium / Magnesium) concentration

7. Factors Affecting Choice
Drilling Data
Water Depth -- Hole Size
Hole Angle -- Torque/Drag
Drilling Rate -- Mud Weight
Maximum Temperature

8. Factors Affecting Choice
Potential Problems
Shale Problems -- Bit/BHA Balling
Stuck Pipe -- Loss Circulation
Depleted Sands

9. Factors Affecting Choice
Rig/Drilling Equipment
Remote Location
Limited Surface Capacity
Good Mixing Capacities
Good Mud Pumps
Good Solids Control Equipment

10. Factors Affecting Choice
Contamination:
Solids Cement
Salt Anhydrite's/Gyp
Acid Gases
CO2
H2S

11. Solids Content v. Mud Density
60
50
40
30
20
10
0
+ 10% LGS
+ 5% LGS
9 10 11 12 13 14 15 16 17 18 19 20 21 22
Mud Weight, lbs/gal
Volume Percent Solids
Barite
Hematite
Low Gravity Solids
+ 10% LGS
+ 5% LGS
Solids Content vs Density

12. PV & YP v. Mud Wt, lbs/gal
50
45
40
35
30
25
20
15
10
5
0
Max Recommended MBT
9 10 11 12 13 14 15 16 17 18 19 20 21
Mud Weight, lbs/gal
Plastic Viscosity, Yield Point & MBT
Max Recommended PV
Max Recommended YP
PV, YP vs Density

13. Spud Muds
Basically composed of bentonite and water.
Used to spud (begin) a well
Native Mud (Bentonite incorporated with drilled
solids from the formation as some formations
are bentonitic in nature and increase viscosity)

14. Spud Muds
Low Solids System due to no added weight materials
Low in cost and high penetration rate
Extremely shear thinning

15. Lignosulphonate Systems
This used to be the most common drilling fluid system
used in the industry.
Primary product -lignosulfonate – may contain chrome,
an organic acid which supplies anions (negative ions)
which reduce the YP and Gel strengths by neutralizing the
cations (positive ions) on the clay particles.
System requires an alkaline environment to solubilize the
lignosulphonate. Caustic Soda or Lime should be used to
increase the pH to a minimum of 9.5
Old technology

16. Lignosulphonate Systems
System can tolerate high solids and contamination - by
increasing the concentration of lignosulphonate
Lignite can be used as a supplementary product and, like
lignosulfonate, is an organic acid that supplies anions
which reduce the YP and Gels by neutralizing the clay
particles.

17. Lignosulphonate Systems
Typical Properties:
Density >10.0 ppg
FV (3.5)(MW)+/-
PV/YP see PV/YP Graph
Gels 1-5 / 1-10
pH 9.0 - 11.5
FL as required
LGS 5 - 7 percent

18. Calcium Treated Systems
Calcium added to a clay-water slurry causes flocculation
- an increase in yield point and gel strengths.
This is caused by the Ca2+ cation having higher bonding
energy than the Na+ cation on the clays, thus converting
them to Ca2+ clays.
This results in partial dehydration of the hydrated clay
particles, causing a reduction in the size of the water
envelope around the clay particle. This reduction of the
water envelope allows closer proximity of the clay
particles to each other, resulting in flocculation.

19. Calcium Treated Systems
If a deflocculant is not present or utilized, the size of the
flocks of clay will increase and precipitate out, resulting in
decreased PV’s.
As calcium is added when sufficient deflocculant is
present, partial dehydration will still occur and the water
envelope will be reduced causing a increase in the YP and
Gels initially. This is called a viscosity hump.
Shear, time and temperature causes the clay flocks to
break apart and the anionic deflocculants neutralize the
cationic clay charges, reducing the YP.

20. Calcium Treated Systems
Advantages:
Effective inhibiting system. Low costs. Can be used where
salts are not permitted.
Tolerant of CO2 and H2S contamination
Disadvantages:
Calcium is not tolerant to certain polymers.

21. Potassium Systems
Potassium is an effective ion that minimizes (inhibits)
clay hydration. This is achieved by the ionic base
exchange of potassium for sodium and/or calcium ions
on clay platelets.
Swelling clays are selective toward potassium and will
adsorb potassium ion over the sodium ion.
This exchange of potassium ions occurs when the
potassium-to-sodium ratio exceeds 3 : 1.

22. Potassium Systems
The low hydration energy of the potassium ion
contributes to inter-layer dehydration, resulting in a
compact, tightly held structure.
When ion fixation occurs, the clay platelet loses its water
within the inter-layer space and the platelet becomes
stable.

23. Potassium Systems
KCL PHPA MUD
Developed to stabilize water sensitive shales by means
of potassium ion inhibition.
Minimizes the hydration of shales, which minimizes hole
enlargement, bit and stabilizer balling, sloughing shale
and reduction of permeability in productive zones.
Uses potassium chloride (KCL) as the primary source of
potassium

24. KCL PHPA MUD The Potassium Component
Concentration of KCL required to inhibit the shale being
drilled depends on the shales’ sensitivity to water.
Shale cuttings should be monitored for inhibition during
drilling operations. Insufficient concentrations will cause
the shale to be soft and mushy. If there is a sufficient
concentration of KCL, the shale will retain its integrity.
Concentration of KCL required:
Older Shales: 10 - 15 ppb (3.5 - 5.0 %)
Younger Shales: 30 - 40 ppb (8.5 - 12.5%)

25. The Potassium Component
In some areas potassium salts are not permitted.
However, other chemicals can be used to provide a
source of potassium without using a salt.
Potassium lignites
Potassium Acetates
Are usually more expensive.

26. The PHPA component
PHPA SYSTEMS - designed to provide shale
stabilization (inhibition) and viscosity control in water-base
muds.
PHPA - is a high molecular weight anionic polymer
which has multiple applications and benefits.
PHPA is used in many applications:

27. KCL PHPA MUD The PHPA component
PHPA: Used primarily for shale stabilization
Shale stabilization is achieved through encapsulation,
through viscosifying the water phase, and by the
polymer adsorbing free water.
Encapsulation - is the process by which PHPA wraps
around the clay platelets, preventing water from
entering the interlayer structure of the clays.
By viscosifying the water phase, fluid movement into
the interlayer structure of the clay is slowed.

28. The PHPA component
The stability of the system depends on maintaining the
polymer concentration at the proper range and
controlling the clay content to less than 6.0 percent.
If the polymer concentration is not maintained and the
solids concentration is allowed to increase above the
proper range, the viscosity will increase and anionic
deflocculants (thinners) will be required to stabilize fluid
properties.

29. The PHPA component
MAINTAINING a PHPA SYSTEM
Monitor and maintain proper polymer concentration.
Control solids and MBT in the proper range.
Maintain Calcium at <300 mg/l.
Control pH below 10.0.

30. KCL PHPA MUD The Glycol component
A polymer system may use glycol technology to
provide additional shale inhibition, wellbore stability,
lubricity and good fluid loss. Other benefits include
enhanced cuttings integrity, improved filter cake,
lower dilution rates, less hole enlargement, greater
solids tolerance, reduced bit balling and increased
ROP.
Glycols are environmentally acceptable due to their
low toxicity.

31. The Glycol component
CLOUD-POINT PHENOMENON:
This is the primary mechanism for inhibition
and stabilization.
CLOUD-POINT is the temperature at which polyglycol
changes from being totally soluble to insoluble.****
At temperatures above the cloud point, poly-glycols
form colloidal droplets or micelles
which results in a micro-emulsion.
“Thermally Activated Mud Emulsion” (TAME).

32. Glycol Mud Systems
At temperatures above the cloud point, poly-glycols
form colloidal droplets or micelles which results in a
micro-emulsion.
This is referred to as “Thermally Activated Mud
Emulsion” (TAME).

33. The Glycol component
The TAME provides wellbore stability in three
distinct ways:
Through chemical adsorption
Through micro-emulsion and precipitate pore
plugging
By providing a thinner, less porous filter/wall
cake

34. The Glycol component
The adsorption of insoluble poly-glycols into the
filter/wall cake on permeable formations reduces the
thickness of the filter/wall cake and fluid loss rates.
The poly-glycols provide lubrication and resists balling
since insoluble poly-glycols have an affinity to solids and
can coat solids and other surfaces.

35. The Glycol component
Most poly-glycol systems are designed to become
totally soluble as it cools while being pumped up the
annulus to the surface. But some systems are
designed to keep the poly-glycol insoluble at all
times.

36. The Glycol component
There are several glycols available with a wide range of
cloud points. Systems are usually designed to find the
proper glycol required prior to drilling. Only the proper
glycol will be sent to the drill-site.
These poly-glycols are:
•Broad range clouding PAG blend
•Low salinity clouding,<30,000 mg/l Cl
•Moderate salinity clouding, 30-90,000 mg/l Cl
•High salinity clouding, >90,000 mg/l Cl
•Soluble poly-propylene

37. Silicate Mud Systems
Silicate System:
A salt polymer system with added SODIUM SILICATE.
Developed to provide shale inhibition and hole stability
in areas where oil or synthetic fluid systems would
normally be used.
Formations like micro-fractured shale, chalk, or inter-bedded
dispersive clays are applications for a Silicate
System.

38. Silicate Mud Systems
Inhibition and hole stability is achieved as soluble
silicates precipitate to form an insoluble silicate film in
the hole to prevent water contact with the shale (clay), or
invasion into permeable formations.

39. Silicate Mud Systems
As soluble silicates contact the low pH shales
(clays) of formations, a reduction in pH and a
reaction with divalent cations (Ca2+, Mg2+) on/in the
shale (clay) form a calcium and/or magnesium
silicate coating.

40. Silicate Mud Systems
Soluble silicates are stable only at pH values > 11.0 or
in the absence of cations.
Silicates will precipitate out at pH <11.0 or in the
presence of cations.
Therefore, the pH should be controlled at 11.0 or
greater and cations treated out with Soda Ash.

41. Silicate Mud Systems
Monitor the concentration of silicate, since the
silicate is depleted at high rates when drilling reactive
shale.
This is necessary for the system to provide good
inhibition.
The optimum concentration of 50% active silicate in a
system is approximately 30 ppb.
Greater concentrations result in unstable flow
properties.

42. Silicate Mud Systems
The silica-to-sodium ratio is important for shale
inhibition. Research indicates that ratio ranges
of 2.0-1 to 2.65-1 are best. Higher ratios do not
improve inhibition and may viscosity instability
Inhibition levels of the Silicate system is
comparable to oil and synthetic base systems.

43. Silicate Mud Systems
Further shale inhibition can be achieved with additions
of Glycol and NaCl or KCL.
Glycol added to the system reduces the coefficient of
friction and extends the thermal stability of the system
to 250°F. Therefore, glycol is recommended once the
BHT reaches 190 °F or as needed to reduce torque and
drag.

44. Silicate Mud Systems
• Reservoir damage may occur when drilling
reservoirs which contain hard water.
• Damage may occur due to precipitation of
calcium silicate (cement) or solidification of
sodium silicate into the pore throat of the
rock matrix.
• The same reservoir damage may also occur
if the pH of the invaded filtrate is reduced
over time.

45. Silicate Mud Systems
This system is not as solids tolerant as most
inhibitive systems and not recommend where
densities above 13.5 ppg are needed.
Temperature limitation: 275°F
A silicate system is a high cost, high performance
system and is only recommended for difficult wells
containing water sensitive shales

46. Silicate Mud Systems
Coeficient of Friction (COF) value Silicate fluids vs other mud systems
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
SILICATE Silicate/Glycol PHPA Glycol OBM
Mud system
Coeficient Of Friction

47. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
1. Caustic Soda (NaOH) Caustic Soda Increase pH
2. Caustic Potash (KOH) Caustic Potash Increase pH and K+
3. Lime (CaOH2) Lime Increase pH & treat CO3
4. Gypsum / Anhydrite (CaSO4) Gypsum Increase Ca2+ treat CO3
5. Sodium Bicarbonate (NaHCO3) Sodium Bicarbonate Treat Cement
6. Soda Ash Na2CO3) Soda Ash Treat Hardness
(Ca2+, Mg2+)

48. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
7. Sodium Acid Pyrophosphate SAPP Treat cement & thin mud
8. Citric Acid Citric Acid Decrease Ph
9. Sodium Chloride (NaCl) Sodium Chloride Increase Cl- (WBM)
10. Calcium Chloride (CaCl2) Calcium Chloride Increase Cl- (OBM / SBM)
11. Potassium Chloride (KCl) Potassium Chloride Increase Cl- and K+
12. Zinc Oxide (ZnO) Zinc Oxide Scavenge H2S

49. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
WEIGHTING MATERIALS:
1. BARITE BAR Increase Mud Density
Barium Sulfate (BaSO4)
2. HEMATITE Increase Mud Density
Ferris Oxide (Fe2O3)
3. CALCIUM CARBONATE (CaCO3) Calcium carb Increase Mud Density, LCM

50. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
CLAYS:
1. BENTONITE GEL Increase Viscosity, Decrease FL
2. BENTONITE GEL Increase Viscosity, Decrease FL
(Non-Treated)
3. ATTAPULGITE SALT GEL Increase Viscosity

51. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
THINNER / DEFLOCCULANTS AND FLC PRODUCTS:
1. Lignite LIGNITE Decrease FL, deflocculate mud
2. Chrome Lignosulfonate Deflocculate mud
3. Lignosulfonate Deflocculate mud (Chrome Free)
4. Causticised Chrome Lignite Decrease HT FL, deflocculate mud
5. Resin treated Lignite Decrease HT FL
6. Synthetic Resin (liquid) Decrease HT FL (env)
7. Potassium Lignite Decrease FL & add K+
8. Sodium Polyacrylate Decrease HT FL
9. Polyacrylate (Low MW) Deflocculate mud

52. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
POLYMERS:
1. PHPA PHPA Encapsulate clays
(Partially Hydrolyzed Polyacrylamide)
2. PAC PAC REGULAR Decrease FL increase viscosity
(Poly Anionic Cellulose)
3. PAC LV PAC Low vis Decrease FL
4. PAC (extra low viscosity) PAC ELV Decrease FL
5. CMC CMC Decrease FL & increase viscosity
Carboxy Methyl Cellulose
6. Corn Starch Corn starch Decrease FL
7. Potato Starch Drilling starch Decrease FL

53. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
8. Carboxy Methyl Starch Decrease FL
9. XCD (Biopolymer) XCD Increase LSRV
10. Starch derivative FLO-TROL Decrease FL
11. Clarified Biopolymer FLO-VIS Increase LSRV
12. Bentonite extender Increase Viscosity
13. Clay Flocculent Selectively Flocculate Clays

54. Products and their Applications
CHEMICAL M-I PRODUCT NAME PRIMARY APPLICATIONS
SHALE CONTROL:
1. Shale Inhibitor ASPHASOL Inhibit shale, reduce FL
2. Shale Inhibitor STABLE HOLE Inhibit shale, reduce FL
3. Shale Control GLYDRIL-(GP,LC,MC,HC) Inhibit shale, reduce FL
4. Shale Control SHALE CHEK Control shale
5. Shale Control K-52 Provide K+ for inhibition
6. Shale Control KLA CURE Control shale
7. Shale Control KLA GARD Control shale
8. Shale Control (Cl- free) KLA GARD-B Control shale

55. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
CORROSION INHIBITORS:
1. Water dispersible blended amine Reduce corr. In FW Packer fluids
2. Persistent filming amine Reduce Corr. on pipe
3. Brine soluble filming amine Reduce corr. in clear brines
4. Phosphorus based Corr. inhibitor Reduce corr. in Drilling Fluids
5. 55% Ammonium Bisulfide Oxtgen scavenger Scavenge Oxygen
6. Scale Inhibitor Inhibit scale formation
7. 12% Zn (liquid) Zinc chelate Scavenge low Conc. of H2S
8. Zinc Oxide ZnO Scavenge H2S
9. 25% Gluteraldehyde Biocide Kill Bacteria

56. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
OIL / SYNTHETIC MUD PRODUCTS:
1. Clay Viscosifier Organoclay Increase Viscosity, Gel Strength
2. Premium Clay Viscosifier Organoclay Increase Viscosity, Gel Strength
3. Sag-Reducing Additive Reduce Sag Potential in NAF
4. High temperature Clay Organoclay HT Maintain HT Viscosity in NAF
5. OBM Emulsifier PRIMARY Emulsify Conventional OBM
6. OBM Emulsifier / Wetter SECONDARY Oil wet Conv/ Emulsify Relaxed
7. OBM Wetting Agent Oil wet relaxed OBM
8. Amine Treated Lignite Reduce HTHP FL in OBM
9. Asphaltic Resin Reduce HTHP FL in OBM

57. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
OIL / SYNTHETIC MUD PRODUCTS:
10. OBM Thinner VERSATHIN Thin OBM
11. Rheological Modifier Increase LSRV of OBM
13. Calcium Chloride CaCl2 Reduce Water Activity
14. Olefin based SBM Wetting Agent Oil wet SBM
15. SBM Rheological Modifier Rheology modifier Inc. LSRV in Olefin based SBM

58. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
SPECIALTY PRODUCTS:
1. Detergent for clean-up OBM/SBM CLEAN-UP Clean-up Rig OBM/SBM
2. Drilling Detergent D.D. Reduce surface tension
3. Alcohol-base de-foamer De-foam Mud
4. Silicone-base de-foamer De-foam Mud
5. Low toxicity detergent additive Prevent Bit and BHA balling
6. Low toxicity Lubricant Lubricate well, reduce HTHP FL
7. All purpose lubricant (ENV) Decrease COF, reduce torque/drag
8. Graphite plugging agent Cure LC, (torque/drag/FLC)
9. LCM Blend Cure Lost Circulation

59. Products and their Applications
CHEMICAL COMMON NAME PRIMARY APPLICATIONS
SPECIALTY PRODUCTS:
10. Ground Mica MICA (F,C) Cure lost Circulation
11. Fibrous plugging and bridging agent Fibre (F,M,C) Plug and Bridge perm. form.
12. Ground nut hulls NUT PLUG (F,M,C) Cure Lost Circulation
13. OB-Stuck Pipe freeing surfactant Free Stuck Pipe
14. ENV-Stuck Pipe spotting fluid Free Stuck Pipe (ENV)
15. One Drum Stuck Pipe Spotting fluid Free Stuck Pipe