ch6 - drilling fluids
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Drilling FluidsTRANSCRIPT
Ch. 6 Drilling Fluids
DRILLING FLUIDS
1. Functions and Properties of Drilling Fluids
2. Field Tests on Drilling Fluids
3. Water Based Mud
4. Oil Based Muds
5. Solids Control
6. Programming a Drilling Fluid
Types of Fluid
Air
Composition of WBM
Composition of OBM
FUNCTIONS AND PROPERTIES OF DRLLING FLUIDS
• Remove Cuttings :• Plastic Viscosity/Yield Point• Gel Strength• Density
• Control Formation Pressures
• Density
• Maintain Wellbore Stability
• Density
• Inhibition
FUNCTIONS AND PROPERTIES OF DRLLING FLUIDS
• Cool and Lubricate the Bit :• Fluid Content
• Transport HHP :• Viscosity• Yield Point• Density
FIELD TESTS ON DRILLING FLUIDS
• Density
• Viscosity
• Filtration
• Sand Content
• Liquid and Solid Content
• Ph
• Alkalinity
• Chloride Content
• Activity
• CEC
Mud Balance
Mud Balance
Marsh Funnel
Marsh Funnel
Fann Viscometer
PV and YP
Typical Viscosities
Typical Yield Point
Filtration Device
Solids Content Device
OIL BASED MUDS
• Water in oil Emulsion• Wettability Control• Balanced Control• Viscosity Control• Filtration Control
Structure of Oil Based Mud
SOLIDS CONTROL• Introduction :
– Screening – Settling – Dilution
• Solids Control Equipment :– Vibrating Screens– Hydrocyclones– Decanting Centrifuges– Mud Cleaner
• Systems
Solids Size Distribution
Hydrocyclone (Lightweight Mud)
Hydrocyclone (Heavyweight Mud)
Solids Distribution
Centrifuge
Solids Control System(Lightweight Mud)
Solids Control System (Heavyweight Mud)
DRILLING FLUID MECHANICS
1. Introduction
2. Flow Patterns and Reynolds Number
3. Rheological Models
4. Frictional Pressure Drop in Pipes and Annuli
5. Frictional Pressure Drop Across a Bit
6. Optimising the Hydraulics of a Circulating System
Introduction
• Primary Function of Drilling Fluid
– Remove Cuttings
• Optimum Use of Circulating Fluid
• Optimise ROP
• Circulating Pressure Losses :
– Increasing Flow Rate
– Decreasing Flow Area
– Increasing System Length
– Increasing Density and Viscosity of Mud
Circulation System
Optimising HHP at Bit
Value of HHP
Flow Patterns and Reynolds Number
• Laminar Flow • Turbulent Flow• Transition :
– Newtonian Fluids– Non Newtonian Fluids– Reynolds Number (2100)
FlowPatterns
Rheological Models
• Newtonian
• Non Newtonian :– Bingham Plastic– Power Law
Rheological Models
Newtonian Fluids
Non-Newtonian Fluids
Pseudo-plastic Fluids
Bingham Plastic Fluids
Power Law Fluids
Frictional Pressure Drop in Pipes/Annuli
• Laminar Flow :– Assumptions– General Equation– Newtonian Fluids– Bingham Plastic Fluids– Power Law Fluids
• Turbulent Flow :– Newtonian Fluids– Laminar/Turbulent Transition– Bingham Plastic Fluids– Power Law Fluids
Variables Involved in Calculating Pressure Drop
Model for Frictional Pressure Loss
Turbulent Flow
Friction Factors
Friction Factors
Frictional Pressure Drop Across a Bit
• Nozzle Sizing
Bit Nozzle