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Drilling Muds Training Presentation


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Drilling Muds Training Presentation

  1. 1. Bentonite: Its Origin Large volumes in western U.S. Formed during Cretaceous Period Formed by volcanic ash
  2. 2. Bentonite Mining
  3. 3. 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)
  4. 4. 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
  5. 5. Mixing System
  6. 6. 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
  7. 7. Make-Up Water Most important block of fluid system! Makes 95-99% of a drilling fluid! Bad Water = Bad Drilling Fluids
  8. 8. 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
  9. 9. 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
  10. 10. 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
  11. 11. Bentonite Settles and Leaves Water on the Surface Bentonite settling due to calcium in water
  12. 12. 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
  13. 13. Check Mix Water pH with pH Strips
  14. 14. 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)
  15. 15. 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
  16. 16. Characteristics of HYDRAUL-EZ Drilling Fluid Viscosity Gel Strength Fluid Loss Sand Content Density, Hydrostatic Head
  17. 17. 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
  18. 18. Units for Bingham Plastic FluidsWe use the following units, typically, to describe therheological 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?
  19. 19. Marsh Funnel and Cup - Viscosity
  20. 20. 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
  21. 21. Viscosity & Pump PerformancePump curves are based on clear water at sea level andunder 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
  22. 22. 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
  23. 23. Gel StrengthTwo methods to increase the gel strength of a drillingfluid 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
  24. 24. 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
  25. 25. One Minute Gel Strength @ 60 Viscosity SUPER GEL-X HYDRAUL-EZ
  26. 26. Four Minute Gel Strength @ 60 Viscosity SUPER GEL-X HYDRAUL-EZ
  27. 27. Ten Minute Gel Strength @ 60 Viscosity SUPER GEL-X HYDRAUL-EZ
  28. 28. Gel Strength No viscosity increase with HDD designed drilling fluids Recommend SUSPEND-IT when coarse sands and gravel are anticipated
  29. 29. 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
  30. 30. Fluid LossTwo methods to “tighten” or reduce amount of fluidgoing 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
  31. 31. Bentonite SuspensionHYDRAUL-EZ Drilling Fluid Seals Borehole Sidewall Hydrostatic Pressure Bentonite Particles Soil Bentonite Filter Cake Formed by Grains Clogging and Bridging
  32. 32. Fine to Medium Sand Water percolating Total saturation through sand
  33. 33. 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
  34. 34. Controlling Fluid LossMinimal Fluid Loss = Borehole Stability
  35. 35. 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
  36. 36. Modified Natural PolymerUsed 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
  37. 37. Holding the Hole OpenMaintaining a stable hole while drilling through soil,sand, gravel or other non-consolidated formationsPositive pressure of drilling fluid (filter cake,circulating pressure, hydrostatic pressure)  Similar to coffee grounds in a vacuum sealed canKeys  Filter cake  Particle bridging character of the polymers in CETCO’s formulations
  38. 38. Density/Hydrostatic Pressure of Boring Fluids
  39. 39. 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
  40. 40. 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
  41. 41. 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
  42. 42. 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
  43. 43. 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
  44. 44. 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
  45. 45. 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
  46. 46. Barrel YieldDescribes the number of barrels of a given viscosity bentoniteslurry 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 bblsExamples210 bbls x 42 gal = 8,820 gallons of slurry185 bbls x 42 gal = 7,770 gallons of slurry90 bbls x 42 gal = 3,780 gallons of slurry
  47. 47. Five Steps to a Successful Borehole Soil Volume Identification Successful Borehole Drilling Planning Fluids Bits & Reamers
  48. 48. 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
  49. 49. CETCO Online Calculation Guides
  50. 50. 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
  51. 51. Sample Input Screen
  52. 52. Five Steps to a Successful Bore - Soil IdentificationCoarse SoilsSand, Gravel, Cobble, Rock, typically use bentonite orbentonite/polymer systemFine SoilsClay and silts, typically use polymer orbentonite/polymer system
  53. 53. Soil Identification Reactive Non-Reactive (Fine Soils) (Coarse Soils)  Clay  Sand  Shale  Gravel  Cobble  Rock
  54. 54. 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
  55. 55. 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
  56. 56. Synthetic Polymers - Used in Reactive SoilsManufactured in liquid and powdered form;they can be tailor made to fit any functionFunctions: Viscosifiers Clay and shale inhibitors Lubricants Borehole stabilizers Very shear sensitive
  57. 57. 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
  58. 58. Clay & Water (Reactive Soils)Mixing clay Polymer and Clay will hydrate Polymer coats claywith water water causing sticking particles and and swelling delays hydration
  59. 59. 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
  60. 60. CLAY CUTTER Breaks Down Reactive SoilsAdding CLAY CUTTER to granular Granular bentonite/reactive soils arebentonite and water broken down (instead of being encapsulated) and in a more flowable state
  61. 61. 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
  62. 62. Reducing Fluid Loss REL PAC 40 Viscosity 40 Viscosity HYDRAUL-EZ fluid HYDRAUL-EZ fluid with REL PAC
  63. 63. 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
  64. 64. Example: Alternating Clay & Sand Sand Reactive Clay
  65. 65. Example: Difficult Conditions
  66. 66. 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
  67. 67. Avoid Creating Bottlenecks in the Bore PathRotate the bit through sections where push-steering corrections were performed tomaintain annular spacing
  68. 68. 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
  69. 69. Bit Selection – The Proper Bit is Critical for a SuccessfulPilot Hole
  70. 70. 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
  71. 71. Spiral or Fluted Reamer Versatile type of reamer Used in sand, silty soils, and rocks & cobbles Avoid using spiral or fluted reamers in clay
  72. 72. Spiral Reamer In Clay
  73. 73. 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)
  74. 74. Barrel Reamer or Packer Used in uniform soils and loose sands Used with high viscosity to maintain borehole stability Makes a great boat anchor!
  75. 75. Frac-Outs and BulgingPavement 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 sideAnnular space is maintained through proper drillingfluid 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
  76. 76. Preventing Frac-OutsFrac-outs occur when the circulating pressure inthe 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
  77. 77. A Little Bit of Volume and Pressure CanCause a Lot of Damage
  78. 78. Damage Repair is Costly
  79. 79. 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
  80. 80. Don’t Forget an Important Rule of Thumb In HDDHole diameter must be at least 1 ½ times the diameter of the product line
  81. 81. 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
  82. 82. 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.
  83. 83. 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
  84. 84. Let the Exit Flow Be Your Guide
  85. 85. Five Steps to a Successful Borehole Soil Volume Identification Successful Borehole Drilling Planning Fluids Bits & Reamers
  86. 86. 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 @ Utilize the CETCO HDD Estimator:
  87. 87. 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 PLUSControl fluid loss, losscirculation, and frac-outs INSTA-VIS DRY Density, Hydrostatic ACCU-VISReduce torque associated with Head PROSHOTsticky soil CLAY CUTTER CLAY CUTTER DRY Control sub-surface pressure DRILL-TERGE