3. • A drilling fluid is any fluid that is used in
drilling operation in which the fluid is
circulated or pumped from the surface
• Down the drill string through the bit and back
to the surface via annulus
• When to you talk about drilling 4 basic
questions arise why when where how
• Today I am here to discuss and clear some
concepts
4.
5. What is drilling fluid?
• Drilling fluid is nothing but simply mixture of
mud and clay
• Why drilling fluid is employed?
• The main aim is that to bring out the cutting
from the bottom and pressure
• For this the drilling fluids must have 2
properties
• 1. viscosity 2. density
6. Why drilling fluid ?
• Clean the bottom of the hole
• Cool, clean and lubricate the drill bit
• Maintain the walls in the hole
• Reduce friction between drill pipe and well bore
• Prevent the inflow of fluids from well bore
• Form a thin permeable filter cake
• Be non damaging to the producing formation
• Be non hazardous to the environment and the
personnel
7. Terminology
• When we talk about drilling fluids there is a
particular properties like gel strength , plastic
viscosity , yield point and fluid loss
• Fluid loss: The leakage of the liquid phase of
drilling fluid into the formation matrix
resulting in undesirable build up of solid
material . This is the reason why drilling fluids
are added with fluid loss additives
• Ex: modified starch etc
8.
9. • Gel strength: The shear stress measured to the low
shear rate after a mud has set for a period of time
• The time period of testing may from to 10 seconds to
10 minutes according to the API standard
• The gel strength is a important fluid property because it
demonstrates the ability to the suspend the drill solid
and weighting material when circulation is ceased
• Ex: In WBM acid gases carbon dioxide and hydrogen
sulphide
• In oil based mud treatment with organic gelling
material and particles in mud
• If these are not circulated it form bridge and fill and can
form a stuck , lost circulation
10.
11. • Yield point: it is the resistance of initial flow
of fluid or the stress required in order to move
the fluid .
• It is the attractive forces between the colloidal
particles
• In wbm the yp increases with increase in
temperature , contaminants etc
• In obm drill solids , low temperature are
favoured for increase in yp
12.
13. • Plastic viscosity : it is the resistance to the
flow a fluid .
• It is caused by the mechanical friction within
the drilling mud due to interaction between
solids of mud and cutting solid
• PV indicates that mud is capable of drilling
rapidly because of low viscosity exiting the
drill bit
14.
15. Types of mud
• Water based mud (WBM)
• Oil based mud (OBM)
• Synthetic fluids based mud (SBM)
• Polyols
• Additives
• Air based mud but majority of drilling fluids
are WBM & OBM and different types of
drilling fluids for different type of wells
17. Comparison
WBM
• These can replace OBM in a
cost-effective manner for
shale instability
• No water based muds are
stable are 400 F
• Less toxic and can meet
environmental issues
• In this we can control pv ,
yp , fluid loss
OBM
• A lot of additives are to be
used for shale instability
case
• Oil based muds are stable
above 400F
• More toxic and toxicity
affects over a large area
• In this we cannot control
over 30,000 psi and other
temp conditions less than 25
c
18. Advantages of bio polymers
with less toxicity
• High viscosity at low concentration
• Plastic viscosity values are less
• Enabling easy injection
• Stability of the polymer viscosity to salinity,
temperature and alkaline conditions
• However smaller quantities of caustic soda and
kcl for infiltration are used
• This can solve the environmental issue
19. Disadvantages
• The main disadvantage is the toxicity and
disposal of the drilling mud
• There is no particular precedence in the mud
• High risk is involved as it needs a lot of
analysis
• Highly skilled labour and engineers along with
cutting edge technology are also not able to
produce desirable results
23. Conclusion
• Bio polymers are to viscosify the drilling fluid
and schlerogen is more compatible with salt
when compared to xanthan gum
• The core point is also make sure of problems
with drilling fluids and dealing with
environmental concerns of the fluids
• So here by I can conclude that WBM muds are
most sustainable with bio polymers
24.
25. References
• Rheological properties of bio polymers drilling
fluids– Samira Baba ahmed , Mansour
belhadri
• Drlling fluids : State of art --- Ryen caenn,
George V. chillingar