A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water, other liquids (such as petroleum) or gases (such as natural gas), as part of a geotechnical investigation, environmental site assessment, mineral exploration, temperature measurement, as a pilot hole for installing piers or underground utilities, for geothermal installations, or for underground storage of unwanted substances, e.g. in carbon capture and storage.

1. Presented By
A.Bharat kumar

2. Bore hole
 Mechanical alteration of rock by drilling.
 Alteration of fluid distribution with in
the rock pores.
 Mechanical alteration of bore hole
geometry by the circulation mud.

4. Conditions of bore hole
 Hole size
 Drilling
 Mud cake
 Mud filtrate

5. Hole size
 Build up of mud cake which creates
sloughing.
 Two types.
a) Over gauge hole:- large dia than drill bit
dia.
b) Under gauge:- Hole narrower than drill
bit.

7. Drilling mud
 It destabilizes the bore hole size by
creating following problems.
 Creates mud filter cake.
 Creates swelling problems.

9. Mud cake
 Prevention is necessary for further
invasion of liquid.
 Necessary determination of mud cake
thickness and volume by filter pressure.

11. Mud filtrate
 Fluid of drilling mud enters the
permeable zone.
 Filtrate is usually water.

13. Types of bore hole
problems
 Pipe sticking
 Loss of circulation
 Hole deviation
 Pipe failures
 Bore hole instability
 Mud contamination
 Formation damage

14. Con….
 Hole cleaning
 Equipment and personnel-related
problems
 Drilling problems can be very costly

15. Uses of bore hole
 House hold/leisure bore hole:-
House holds, communities and leisure
industries with bore holes are self-
reliant, they determine and manage their
water usage and they do not have to
adhere to municipal water restrictions
or pay hefty water bills each month.

16. Con……
 Irrigation bore hole:- Water is used
for irrigation, maintaining parks, golf
courses and race track.
 Live stock bore hole :- Bore holes are
beneficial to agricultural projects,
farming activities and even construction
projects.

17. CON…...
 Rural area bore hole:- improves
socio –economic conditions in rural
areas where school, hospitals and
residence require large amounts of
water.

18. Advantages
 Savings in potable water requirements.
 Long term financial benefit.
 Control water table fluctuations.
 Devolution of maintenance from service
provider.
 Research and development
opportunities.
 Job creation / opportunities.
 Aid to relieve strain on natural
environment.

19. Disadvantages
 Initial capital layout.
 Possible soil subsidence.
 Possible impact on wetland system.
 More ground water protection and
pollution prevention required.
 Potential health risks to humans.
 Drop in ground water level due to over –
abstraction.
 Iron staining in certain area.