Volume 8 – Mechanical and Electrical Services - Malaysia Geoportal

Chapter 3 GROUND WATER FACILITIES
Steel casing offers superior strength and resistance to mechanical damage. Plastic and fibrecomposite
casing materials are corrosion resistant and structurally durable when installed properly.
Professional engineer or experienced driller should carry out the following job:
- Design of casing string
- Holding casing in position
- Preparation for running casing
- Running the casing string
3.11 WELL DEVELOPMENT
Well development should consider the following:
- Type of development
- Principle of development
- Washing and back washing
- Bailer and plunger pump
- Airlift development
- Mechanical surging
- Hig velocity jetting tools
- Finishing the well construction
3.12 PUMPING TEST
3.12.1 Reason for test pumping
There are two main reasons for conducting a pump test:
- Construction practiced to produce well is efficient.
- To determine the optimum long term yield of a well, what level the pump suction or intake
should be set to maintain the optimum yield.
3.12.2 Method of measuring flow rates
One important requirement of any pumping test is the ability to accurately determine the rate of flow
from the bore. This can be done in several ways:
- Measure in a known volume container
- Weir board
- Orifice bucket
- Orifice meter
- Flow meter
3.12.3 Test pumping procedures
Test pumping is carried out by pumping from the bore at a constant rate and at the same time
measure the water level in the pumped bore at prescribes times in order to check that pumping rate
is constant to within about 10%.
Should the water level inside the pump bore fall below the pump suction level, and the pump starts
sucking air, the test should be discontinued and be carried out at the lower discharge rate after the
water level has recovered.
3-8 March 2009