2. Outline
Introduction.
Basic Function of Drilling Fluids.
Types of Drilling Fluids.
Drilling Fluid Tests.
Challenges Related to Drilling Fluids.
Solids Control and Waste Management.
3. Introduction
• Drilling-fluid system commonly known as the Mud System.
• Drilling-fluid systems are designed and formulated to perform
efficiently under expected wellbore conditions.
• The Capacity of the surface system usually is determined by the rig
capacity which is determined by the well design.
4. Outline
Introduction.
Basic Function of Drilling Fluids.
Types of Drilling Fluids.
Drilling Fluid Tests.
Challenges Related to Drilling Fluids.
Solids Control and Waste Management.
5. Basic Functions of Drilling Fluids
1. Transport Cuttings to Surface.
2. Primary Well-Control Method.
3. Preserve Wellbore Stability.
4. Minimize Formation Damage.
6. Basic Functions of Drilling Fluids (Cont.)
5. Cool and Lubricate the Drill String.
6. Provide Information About the Wellbore (Mud Logging).
7. Outline
Introduction
Basic Function of Drilling Fluids
Types of Drilling Fluids
Drilling Fluid Tests
Challenges Related to Drilling Fluids
Solids Control and Waste Management
9. Outline
Introduction.
Basic Function of Drilling Fluids.
Types of Drilling Fluids.
Drilling Fluid Tests.
Challenges Related to Drilling Fluids.
Solids Control and Waste Management.
10. Drilling Fluid Tests
There are two types of tests:
Field Tests
The drilling-fluids specialist in the field
(Mud Engineer) conducts a number of tests
to determine the properties of the drilling-
fluid system and evaluate treatment needs.
Laboratory Tests
Extensive testing of fluid is performed in
the design of the fluid; either to achieve
fluid characteristics or to determine the
performance limitations of the fluid.
16. Outline
Introduction
Basic Function of Drilling Fluids
Types of Drilling Fluids
Drilling Fluid Tests
Challenges Related to Drilling Fluids
Solids Control and Waste Management
17. Challenges Related to Drilling Fluids
• All drilling challenges relate to the fundamental objective of
maintaining a workable wellbore throughout the well-construction
process.
• A workable wellbore can be drilled, logged, cased, cemented, and
completed with minimal nonproductive time.
• The design of the drilling-fluid system is central to achieving this
objective.
18. Challenges Related to Drilling Fluids (Cont.)
Loss of Circulation
• Lost circulation always causes nonproductive time that includes the cost
of rig time and all the services that support the drilling operation.
Solutions
Leak-off Test (LOT)
Formation Integrity Test (FIT)
19. Challenges Related to Drilling Fluids (Cont.)
Stuck Pipe
• Stuck pipe often is associated with well-control and lost-circulation events,
the two other costly disruptions to drilling operations, and is a significant
risk in high-angle and horizontal wells.
Reasons
Solutions
• Lubricants for WBFs
• Spotting Fluids
20. Challenges Related to Drilling Fluids (Cont.)
Barite Sag
• Barite or weight material sag is a problem of drilling mud
and it occurs when weighting materials separate from
liquid phase and settle down.
• Dangers
• Solutions
Light Mud
Heavy Mud
21. Outline
Introduction
Basic Function of Drilling Fluids
Types of Drilling Fluids
Drilling Fluid Tests
Challenges Related to Drilling Fluids
Solids Control and Waste Management
22. Solids Control and Waste Management
Fundamental Concepts:
• Contamination of drilling fluids is a signal if the rig either is not
making hole or soon will be stuck in the hole it is making.
• Before the mechanical solids-removal equipment, dilution was used
to control solids content in the drilling fluid.
• The typical dilution procedure calls for dumping a portion of the
active drilling-fluid volume to a waste pit and then diluting the solids
concentration in the remaining fluid by adding the appropriate base
fluid, such as water or synthetic oil.
23. Solids Control and Waste Management (Cont.)
1- Solids Concentration
• Increasing solids concentration in drilling fluid is a problem for the
operator, the drilling contractor, and the fluids provider.
• Increasing solids content in a drilling fluid leads to a lower ROP and
other problems such as:
• High viscosity and gel strength.
• High torque and drag.
• Stuck pipe caused by filtrate loss.
• Poor cement jobs caused by excessive filter cakes.
24. Solids Control and Waste Management (Cont.)
2- Particle Size and Surface Area
• Drilled solids vary in size from < 1 μm to 15,000 μm in average
particle diameter.
• Colloidal-sized particles are < 2 μm (average particle diameter)
and will not settle out under gravitational forces.
• Ultra-fines range from 2 to 44 μm and are unlikely to settle out of
a drilling fluid unless it is centrifuged.
25. Solids Control and Waste Management (Cont.)
2- Particle Size and Surface Area (Cont.)
• In bentonite particles, the exposed surfaces of fine drilled solids
contain charges that increase the viscosity and gel strengths of
the drilling fluid.
• The viscosity and fluid loss properties of a drilling fluid are difficult
to control with high concentrations of drilled solids that are < 20
μm.
• Today, fluid-technology advances have solved many of the
problems that contribute to fines buildup in drilling fluids.
26. Solids Control and Waste Management (Cont.)
3- Separation by Settling
• Hydro-cyclones, centrifuges, and settling tanks rely on settling
velocity to concentrate and separate solids from slurry.
• Settling velocity is described mathematically by Stokes’ law
which states that the settling velocity is inversely proportional to the
viscosity of the liquid or slurry.
• Stokes’ Low
Vs
d
ρp
ρl
g
η
the settling velocity because of G-force,
the particle diameter,
the density of the particle,
the density of the liquid, ∝
the acceleration or G-force,
the viscosity of the liquid
2( − )
27. Solids Control and Waste Management (Cont.)
4- Screen Selection
• Screens are the only solids-control devices that are changed to handle
changes in fluid properties or drilling conditions.
• Screens generate the bulk of drilling waste and reclaim the bulk of
the mud.
• Screens must be able to handle the full circulation rate.
• Screens are the only devices on a rig that separate solids on the basis
of size as mentioned before.
28. Solids Control and Waste Management (Cont.)
4- Waste Volumes
• The combined waste volume of cuttings that are created while drilling
and the excess or spent drilling fluid might be the best measure of
performance and cost savings offered by a fluids system.
• Minimizing the volume of spent mud and cuttings is the key to
effective waste management.
• The increase in volume of the wet cuttings stems only partly from the
added volume of cavings, washouts, or drilling a non-gauge hole.
29. Solids Control and Waste Management (Cont.)
Total Fluids Management
• This process design is the key to help improve the economics and
minimizing the environmental impact of drilling activities.
• The most important questions during the planning of the project
1. What equipment best suits the drilling-fluid program and
waste-disposal options?
2. What are the solids loading and liquid loading that the
equipment must handle?
3. How much time will it take to install equipment, and who will
install it?
4. Are pumps, piping, chutes, conveyors, etc., adequate for the
intended service?
30. Solids Control and Waste Management (Cont.)
Total Fluids Management (Cont.)
5. Is there enough power on the rig for the proposed equipment set?
6. Is the space available to install the proposed equipment set?
7. Can the drilling-fluid program be modified to assist the mud- and
cuttings-treatment system?
8. What information needs to be collected and reported?
9. What training needs to take place before startup?
10. What safety issues need to be addressed?
11. What environmental issues need to be addressed?
12. What contingency or emergency operations need to be planned?
31. Outline
Introduction.
Basic Function of Drilling Fluids.
Types of Drilling Fluids.
Drilling Fluid Tests.
Challenges Related to Drilling Fluids.
Solids Control and Waste Management.
