Chapter 1 Introduction & Objectives

Question 1

Functions of Drilling Fluids

Answer 1

1. Remove cuttings from well
2. Control formation pressure
3. Suspend & release cuttings
4. Seal permeable formations
5. Maintain wellbore stability
6. Minimize reservoir damage
7. Cool, lubricate & support the bit and drilling ass.
8. Transmit hydraulic energy to tools & bit
9. Ensure adequate FE
10. Control corrosion
11. Facilitate cementing & completion
12. Minimize impact on environment
13. Prevent gas hydrate formation

Question 2

Common types of drilling fluids

Answer 2

1. WBM :
   - Dispersed system
   - Non dispersed system
2. Invert Emulsion DF (NADF)
   - OBM
   - SBM
   - Ester based mud

Question 3

What is Dispersed System?
Advantages & Disadvantages?

Answer 3

Allowing clay to be incorporated with the mud system to provide viscosity & fluid loss control

Advantages:
- Once dispersed clay from formation, will break cutting to smaller size
Disadvantages:
- In shallow area, clay dispersed and caused hole enlargement
- As we drill shale formation, shale dispersed

Question 4

What is Non-Dispersed Polymer System?
Advantages & disadvantages?

Answer 4

As we drill clay, we want to prevent clay to be part of our drilling mud system

Advantages:
- Since it prevent clay to be part of the system, less solid in system - better control of solids - less frictional loss as we drill - overall circ system is better
Disadvantages:
- Cuttings will be bigger, hence challenging in hole cleaning

Question 5

Drilling rig mud circulations systems

Answer 5

Mud pump (suck mud from active pit) - Standpipe manifold - TDS - Down to the drill string - out from bit - annulus - Flowline - Shale shaker - degasser - sandtrap - desilter - centrifuge - settling tank - active pit