2. Bentonite: Its Origin
Large volumes in
western U.S.
Formed during
Cretaceous Period
Formed by volcanic
ash
http://www.webcamcruise.com/USA%20Map_fichiers/usa_map.jpg
4. Wyoming Sodium Bentonite
High swelling clay
Ability to adsorb large
quantities of water
Composed of many stacks of
platelets like a stack of cards
Expands up to 20 times its
volume
One inch3 covers 66 football
fields
One inch high contains
between 35,000-40,000 layers
(stresses good mixing)
5. Venturi Style Mixing Hopper
Bentonite going into
hopper @ 200 mesh
(74 Microns)
Bentonite platelets (1/2 Micron)
mechanically separated by high
velocity fluid from jet hopper
Hopper Jet Venturi Pipe
7. Examples of Un-yielded Bentonite
This image shows a poorly This image shows the un-
mixed 40 Viscosity SUPER yielded bentonite on your
GEL-X poured over the hand when dipping it into
screen on a Marsh Funnel the mix tank
8. Make-Up Water
Most important block of fluid system!
Makes 95-99% of a drilling fluid!
Bad Water = Bad Drilling Fluids
9. Do These Problems Sound Familiar?
Bentonite does not mix like it should
When we turn off the mixing equipment the
bentonite settles and leaves water on the surface
It takes a lot more bentonite to get the same
viscosity
The pump is making all kinds of noises when
pumping the slurry
Polymer gets all stringy when we mix it
10. Make-Up Water
Is there a problem with the Bentonite?
Probably not.
Most likely the culprit is low pH (<9.5) and or
hardness (calcium)
When contaminants are present, the stack of cards
does not want to separate and disperse
11. Effects of Soda Ash on Bentonite in Water
Soda ash increases the negative charge on bentonite
More water is adsorbed
Dispersion of clay platelets increases
Na2CO
+ +
Soda ash also promotes dispersion of the drill cuttings
12. Bentonite Settles and Leaves Water on the Surface
Bentonite settling due to calcium in water
13. What to Do?
Check pH (7 is neutral)
HYDRAUL-EZ and polymers like a pH of
approximately 9.5+
Raise the pH with soda ash (sodium carbonate).
This also precipitates out calcium
Normal treatment is ¼ to ½ pound per 100 gallons
of water
15. The pH Scale
H+ Concentration (Moles/Liter) pH Value
100 0 1 Molar Hydrochloric acid (HCI)
10-1 1 Stomach Acid, Lime Juice
10-2 2 Lemon Juice
Increasingly Acid (H+ >
10-3 3 “Acid Rain” (2.5-5.5), Vinegar, Cola
10-4 4 Beer
10-5 5 Black Coffee, Tea
OH-)
10-6 6 Normal Rain (5.6)
Bentonite 10-7 Neutral 7 Pure Water, Saliva, Blood, Sweat
(H+=
Mixing 10-8 OH-) 8 Seawater (7.8-8.3)
10-9 9 Baking Soda
Increasingly Basic (H+ <
10-10 10 Phosphate Detergents, Chorine Bleach
10-11 11 Household Ammonia
Reference: Audesirk,
10-12 12 Washing Soda T., Audesirk, G., &
Byers, B. 2003. Life On
Earth. Third Edition.
10-13 13 Oven Cleaner
OH-)
Prentice Hall. Upper
Saddle River
10-14 14 1-Molar Sodium Hydroxide (Na0H)
16. Functions of HYDRAUL-EZ Drilling Fluid
Cool bit & lubricate the
hole
Clean the hole, suspend
& transport cuttings
Hold the hole open,
stabilize the hole
Control fluid-loss, loss
circulation, and frac-outs
Reduce torque
associated with sticky
soil
Control sub-surface
pressure
17. Characteristics of HYDRAUL-EZ
Drilling Fluid
Viscosity
Gel Strength
Fluid Loss
Sand Content
Density,
Hydrostatic Head
18. Viscosity
The resistance of a fluid to flow; the greater the
resistance, the greater the viscosity or thickness
Measured with a marsh funnel and cup
Viscosity only tells us the thickness of a fluid
Two fluids with the same viscosity can be vastly
different in terms of its ability to clean the hole
19. Units for Bingham Plastic Fluids
We use the following units, typically, to describe the
rheological behavior of drilling fluids
Plastic viscosity, PV (cp)
Yield Point, YP (lb/100 ft2)
Apparent Viscosity, AV (cp)
Gel strengths (??)
How can this possibly make any sense?
21. Viscosity & Pump Performance
Higher viscosity fluids will reduce the flowability of
cuttings
Higher viscosity fluids will drastically reduce pump
performance
Higher viscosity fluids will increase pumping and
material costs
22. Viscosity & Pump Performance
Pump curves are based on clear water at sea level and
under ideal conditions
Example
40 gpm pump with clear water, 26 viscosity
40 viscosity – 10-15% capacity = 34-36 gpm
60 viscosity – 25-30% capacity = 28-30 gpm
80 viscosity – 40-50% capacity = 20-24 gpm
23. Gel Strength
Most important drilling fluid characteristic
The ability of HYDRAUL-EZ to form gels and suspend
cuttings in borehole
If drill cuttings are not suspended, they will pack off
borehole and cause pressure buildup, fracturing, and
stuck pipe
24. Gel Strength
Two methods to increase the gel strength of a drilling
fluid
1. Add more HYDRAUL-EZ, which also increases viscosity
(resistance to flow)
2. Add a gel strength enhancing polymer to HYDRAUL-EZ slurry
HYDRAUL-EZ/polymer system - HYDRAUL-EZ with
SUSPEND-IT is most desirable since it forms a high gel
strength, pump-able slurry
25. Gel Strength
If cuttings are flowing out
of the hole, we know we 45
have an open hole 40
35
30
If the hole is open, we don’t 25
get stuck 20
15
10
HYDRAUL-EZ offers 5
0
superior gel strength 1 0 MIN GEL
S UPER GEL -X
HYDR AUL -EZ
26. One Minute Gel Strength @ 60 Viscosity
SUPER GEL-X HYDRAUL-EZ
27. Four Minute Gel Strength @ 60 Viscosity
SUPER GEL-X HYDRAUL-EZ
28. Ten Minute Gel Strength @ 60 Viscosity
SUPER GEL-X HYDRAUL-EZ
29. Gel Strength
No viscosity increase
with HDD designed
drilling fluids
Recommend
SUSPEND-IT when
coarse sands and gravel
are anticipated
30. Fluid Loss
Measure of amount of drilling fluid lost through a
permeable formation
Fluid loss can be measured with a filter press
Bentonite platelets shingle off wall of the hole and
form a filter cake when slurry is pumped under
pressure
This cuts off water to surrounding sand or gravel
31. Fluid Loss
Two methods to “tighten” or reduce amount of fluid
going into formation
Add more HYDRAUL-EZ, which increases platelets but
increases viscosity (resistance to flow)
Add fluid loss polymer to HYDRAUL-EZ slurry HYDRAUL-
EZ/polymer system – HYDRAUL-EZ with SUPER PAC or REL
PAC is most desirable since it forms a low solids pump-able
slurry
32. Bentonite Suspension
HYDRAUL-EZ Drilling Fluid Seals Borehole Sidewall
Hydrostatic
Pressure
Bentonite Particles
Soil Bentonite Filter Cake Formed by
Grains Clogging and Bridging
33. Fine to Medium Sand
Water percolating Total saturation
through sand
34. Fine to Medium Sand
HYDRAUL-EZ and REL- Water or drilling fluid with
PAC Drilling Fluid poor fluid loss
MINIMAL Fluid Loss HIGH Fluid Loss
36. Fluid Loss
SUPER PAC and
REL-PAC enhance the
performance of
HYDRAUL-EZ
A thick filter cake does not
translate to a reduction in
fluid loss
37. Modified Natural Polymer
Used in Coarse Non-Reactive Soils
Manufactured in liquid and powdered form, cellulose polymers are
used primarily to control fluid loss and stabilize difficult holes
REL-PAC and SUPER PAC – Dry and liquid cellulose polymers which
are added to HYDRAUL-EZ systems to create superior borehole
stability
38. Holding the Hole Open
Maintaining a stable hole while drilling through soil,
sand, gravel or other non-consolidated formations
Positive pressure of drilling fluid (filter cake,
circulating pressure, hydrostatic pressure)
Similar to coffee grounds in a vacuum sealed can
Keys
Filter cake
Particle bridging character of the polymers in CETCO’s
formulations
40. Borehole Stability
Major function of HYDRAUL-EZ fluid is to keep the
hole open
Hole is held open by hydrostatic pressure from a
HYDRAUL-EZ fluid pressing against a lower formation
pressure – across a filter cake
The pressure difference need not be great, but must
always be positive
41.
42. What Is Loss Circulation?
Loss circulation refers to the total or partial seepage of
drilling fluid into the formation through crevices or
porous media
Not to be confused with frac-outs which refer to fluid
breaking through the surface
43. Coarse Unconsolidated Formations
Sand
Gravel
Partial and or gradual loss of return flow
may be experienced in coarse soil
conditions.
Utilize a drilling fluid with good fluid-
loss control such as a HYDRAUL-EZ/PAC
polymer fluid (soda ash is also important
to get maximum yield out of HYDRAUL-
EZ)
Reduce the mud weight as much as
possible by good solids control practices
and checking mud properties frequently
44. Driller-Created Loss Circulation Problems
High solids/high density drilling fluids increase
hydrostatic pressure on formations
Example:
Mud Weight X 0.052 X Depth = Hydrostatic Pressure
9.0 pound mud @ 200’ depth:
9.0 X 0.052 = 0.468 X 200’ = 93.6 PSI of Hydrostatic Pressure on the
Formation
14 pound mud @ 200’ depth:
14 X 0.052 = 0.728 X 200” = 145.6 PSI of Hydrostatic Pressure on the Formation
45. Driller-Created Loss Circulation Problems
Failure to adequately transport
cuttings to the surface
Inadequate gel strength and or
annular ascending velocity to
transport cutting to the surface,
and suspend cuttings when
circulation is stopped can result
in the bridging of drill cuttings
around the drill stem which can
block return flow, over pressure,
and fracture the formation
46. Driller-Created Loss Circulation Problems
Failure to control the hydration
of reactive soils
Reactive clays can swell up and
create blockages that prevent
return flow from exiting the
bore and over-pressure the
formation causing fractures and
loss circulation
Utilize synthetic polymer for
controlling reactive soils
47. Driller-Created Loss Circulation Problems Hole Swabbing
Thick, poorly-yielded
bentonite drilling fluids (not
using soda ash) along with a
failure to utilize modified
natural polymers (PAC
polymers) to control water-
loss can result in high fluid-
loss conditions
A thick ineffective filter cake
can cause swabbing (suction)
of the hole, when downhole
tooling is pulled, resulting in
hole collapsing and loss
circulation problems
48. Barrel Yield
Describes the number of barrels of a given viscosity bentonite
slurry that can be made from a ton of clay
SUPER GEL-X High Yield Bentonite = 200-220 bbls
HYDRAUL-EZ HDD specialty bentonite = 165-185 bbls
PREMIUM GEL API grade = 90 bbls
Examples
210 bbls x 42 gal = 8,820 gallons of slurry
185 bbls x 42 gal = 7,770 gallons of slurry
90 bbls x 42 gal = 3,780 gallons of slurry
49. Five Steps to a Successful Borehole
Soil
Volume
Identification
Successful
Borehole
Drilling
Planning
Fluids
Bits
& Reamers
50. PLAN for SUCCESS!
Time is Money!
Planning Phase Saves Time
Jobsite Layout
Needs:
Manpower
Equipment Needs (Tooling, Vacs, Recycling)
Product Needs
Jobsite Water Source (Fire Hydrant)
Disposal Options
52. Why Use a Software Based Mud Program?
Allows for more accurate bidding of jobs
Ensure you have the correct products on the job-
site
Ensure you have proper quantity of products on
the job
Printed report can be used with your submission
Engineers are using this to assist in specs
56. Five Steps to a Successful Bore - Soil Identification
Coarse Soils
Sand, Gravel, Cobble, Rock, typically use bentonite or
bentonite/polymer system
Fine Soils
Clay and silts, typically use polymer or
bentonite/polymer system
58. Five Steps to a Successful Bore -
Drilling Fluids
There are no universal soils and there are no
universal drilling fluids
Match the drilling fluid to the soil type
Use bentonite as a base for all soil conditions
Polymers & additives are added to bentonite
drilling fluids to match soil conditions
59. Polymer Additives
Designed as additives for HYDRAUL-EZ & SUPER
GEL-X drilling fluids, not a replacement
First used as drilling fluids in the late 1930’s
Specifically designed for a particular drilling
situation
Three basic categories; synthetic, modified
natural, and natural polymers
60. Synthetic Polymers - Used in
Reactive Soils
Manufactured in liquid and powdered form;
they can be tailor made to fit any function
Functions:
Viscosifiers
Clay and shale inhibitors
Lubricants
Borehole stabilizers
Very shear sensitive
61. Synthetic Polymers
ACCU-VIS and INSTA-VIS PLUS
– Liquid polymers to increase
viscosity and inhibit hydration
of clay and shale
INSTA-VIS DRY – Dry polymer
for stabilizing borehole and
coating clay and shale
62. Clay & Water (Reactive Soils)
Mixing clay Polymer and Clay will hydrate Polymer coats clay
with water water causing sticking particles and
and swelling delays hydration
63. CLAY CUTTER
A concentrated, non hazardous,
proprietary clay inhibitor that
can be used with either polymer
or HYDRAUL-EZ drilling fluid
systems
An ideal additive for reactive
clay soils
Will greatly reduce or eliminate
clay cuttings from sticking to
each other and to the drilling
tools. Swelling of the bore will
be reduced or eliminated
Rotation and pullback pressures
will be significantly reduced
Can be used in antifreeze tank
for easy spot treatment
64. CLAY CUTTER Breaks Down Reactive Soils
Adding CLAY CUTTER to granular Granular bentonite/reactive soils are
bentonite and water broken down (instead of being
encapsulated) and in a more flowable
state
65. Modified Natural Polymer (Used in Coarse
Non-Reactive Soils)
Manufactured in liquid and powdered form,
cellulose polymers are used primarily to control
fluid loss and stabilize difficult holes
REL-PAC and SUPER PAC – Dry and liquid
cellulose polymers which are added to HYDRAUL-
EZ systems to create superior borehole stability
66. Reducing Fluid Loss REL PAC
40 Viscosity 40 Viscosity
HYDRAUL-EZ fluid HYDRAUL-EZ fluid
with REL PAC
67. Natural, Biodegradable Polymers
No viscosity increase
with HDD designed
drilling fluids
Increases gel strength
SUSPEND-IT is
recommended when
coarse sands and gravel
are anticipated
71. Pilot Hole
Use drilling fluids and additives both ways: if you
need it back-reaming, you will need it on the pilot hole
Maintain an open bore path and steady flow
Avoid over-steering
72. Avoid Creating Bottlenecks in the
Bore Path
Rotate the bit through sections where push-
steering corrections were performed to
maintain annular spacing
73. Five Steps to a Successful Bore
Bits & Reamers
No universal soils Bits
Duckbill
No universal drilling Roller Cone
fluids Geo-Head
No universal bits & Reamers
reamers
Barrel/Packer
Spiral/Fluted
Match downhole
tooling to the soil type Winged/Open
Roller Cone/Hole
Opener
74. Bit Selection – The Proper Bit is Critical for a Successful
Pilot Hole
75. Reamer Selection
Reamer should always be a minimum of 1 ½ times
the diameter of the product line to prevent getting
stuck and frack outs.
Reamer selection is critical for a successful bore
Like fluids, reamers need to be matched to soil
types
Reamers should not restrict the pump’s capacity or
annular flow
76. Spiral or Fluted Reamer
Versatile type of
reamer
Used in sand, silty
soils, and rocks &
cobbles
Avoid using spiral or
fluted reamers in clay
78. Winged or Open Reamer
Used in reactive soil
conditions (i.e. clays)
Minimal surface area for
clay to stick and cause
blockage of annular flow
Good chopping action
(required in reactive soils)
79. Barrel Reamer or Packer
Used in uniform soils
and loose sands
Used with high
viscosity to maintain
borehole stability
Makes a great boat
anchor!
80. Frac-Outs and Bulging
Pavement
Drilling fluid has nowhere else to
go but into the formation
No space between formation and drill
pipe for drilling fluid to return
Reamers such as fluted and spiral ball up
with clay and restrict flow to exit side
Annular space is maintained through proper drilling
fluid additives and good drilling techniques
Open type of back reamers reduce balling of clays and provide
-
a chopping/mixing action while allowing for fluid to flow to the exit side
81.
82. Preventing Frac-Outs
Frac-outs occur when the circulating pressure in
the wellbore exceeds the formation strength
Build-up of solids in drilling fluid lead to really high
mud viscosities, low pump rates, and/or “out-running
mud”
Solution is more drilling fluid and or higher circulation
rates to reduce solids content in returns
83. A Little Bit of Volume and Pressure Can
Cause a Lot of Damage
85. Five Steps to a Successful Bore
Volume
Provide sufficient volume to maintain a flowable
slurry
Calculate drilling fluid volumes based on hole size
and soil type
Determine backream time based on pump
capacity
86. Don’t Forget an Important Rule of
Thumb In HDD
Hole diameter must be at least 1 ½ times
the diameter of the product line
87. Calculating Drilling Fluid Volumes
Volume of hole = Diameter2 ÷ 24.52 = gals/ft
Example: 8” backream and 200 ft bore
8x8=64 ÷24.52=2.61 gals/ft
200 ft bore x 2.61 gals/ft = 522 gals (based on 1:1 ratio)
Requirements for different soils
Sands: 2-3 x volume of hole
Clays: 3-5 x volume of hole
88. Calculating Drilling Fluid Volumes
Estimating bore time based on pump capacity
Example: 200 ft bore x 8” hole; sandy soils
2.61 gals/ft x 2= 5.22 gals x 200 ft=1,044 gallons
Using 10 ft drill stem we need 52.2 gallons per stem:
Pumping 20 gpm takes between 2.5 and 3 minutes per 10 ft. rod.
Pumping 30 gpm takes between 1.5 and 2 minutes per 10 ft. rod.
Pumping 40 gpm takes between 1 and 1.5 minutes per 10 ft. rod.
* Given above examples, reaming time should vary between 25 and 60
minutes.
89. HDD Pumping Volume Requirements
Hole dia. Gal/ Lin. Ft. Coarse Soils (Sands) Fine Soils (Clays)
(in.) = (dia2 ÷24.5) 2 to 3 X Vol. Of hole 3 to 5 X Vol. of Hole
2 0.16 0.32 to 0.48 0.48 to 0.8
4 0.65 1.3 to 1.95 1.95 to 3.25
5 1.02 2.04 to 3.06 3.06 to 5.10
6 1.47 2.94 to 4.41 4.41 to 7.35
7 2.00 4.0 to 6.0 6.0 to 10.0
8 2.61 5.22 to 7.83 7.83 to 13.05
9 3.30 6.60 to 9.90 9.90 to 16.5
10 4.08 8.16 to 12.24 12.24 to 20.4
12 5.87 11.47 to 17.61 17.61 to 29.35
14 8.0 16 to 24 24 to 40
16 10.44 20.88 to 31.32 31.32 to 52.2
18 13.22 26.44 to 39.66 39.66 to 66.10
20 16.32 32.64 to 48.96 48.96 to 81.6
24 23.49 46.98 to 70.47 70.47 to 117.45
30 36.73 73.467 to 110.19 110.19 to 183.65
36 52.88 105.76 to 158.64 158.64 to 264.4
91. Five Steps to a Successful Borehole
Soil
Volume
Identification
Successful
Borehole
Drilling
Planning
Fluids
Bits
& Reamers
92. Up Your Odds for Success!
Utilize drilling fluids as a tool to avoid trouble
instead of an aid to get you out of trouble
Take advantage of the information available on the
CETCO website @ http://www.cetco.com/DPG/
Utilize the CETCO HDD Estimator:
http://www.cetco.com/DPG/HDD.aspx
93. Putting it All Together
Functions of Drilling Fluid Characteristics of HYDRAUL-EZ
a Drilling Fluid
SUPER GEL-X
Cool bit & Lubricate the hole
SUSPEND-IT
Clean the hole Viscosity
(suspend & transport cuttings) SUPER PAC
Gel Strength REL-PAC
Hold the hole open SUPER PAC XTRA-
Fluid Loss LOW
(stabilize the hole)
REL-PAC XTRA-LOW
Sand Content INSTA-VIS PLUS
Control fluid loss, loss
circulation, and frac-outs INSTA-VIS DRY
Density,
Hydrostatic ACCU-VIS
Reduce torque associated with Head PROSHOT
sticky soil
CLAY CUTTER
CLAY CUTTER DRY
Control sub-surface pressure DRILL-TERGE