La Follette Water Well Drilling
Well drilling involves digging a hole into the ground to extract a natural resource such as water or oil from the depths of the earth. The most common types of wells are water wells, which are commonly used to obtain water from underground aquifers. The earliest wells on record were dug by hand and had walls lined with wood or other types of masonry to prevent them from collapsing and caving in. Today wells can be dug mechanically using advanced and relatively expensive equipment or they can be dug manually using affordable tools. Mechanically dug wells are narrower and are much deeper than those dug manually using simple tools. This is a simple and informative guide to the process of well drilling.
How a Well Works
Once the hole is dug, a pipe, which normally has a casing within it, is extended down to the acquirer. A pump is then used to draw water up to the surface and the water then flows into the pipes that connect to different structures where the water will be used or stored. The depth of the well is determined by several factors such as the depth of the aquifer, the structure, and composition of the ground and the quality of ground water. Most water wells in the world are constructed for domestic water use.
The Process of Constructing a Well
The well should be drilled and sited in an area that is free of potential contaminants that can contaminate the ground water e.g. septic systems and buried fuel storage structures like fuel tanks. The well should also be at an acceptable distance from any buildings and the standard is five feet from any structures above ground. There are various well drilling methods, which are determined by the condition and structure of the ground as well as the depth of the underground water. The following are the most common methods used to drill water wells.
• Rotary Drilling
The rotary drill pushes compressed air or water based fluid from its bit into the drill hole to loosen the ground. This process makes well drilling easier and it pumps out the drill cuttings. The drill works faster than most drills, can drill through most ground materials and can reach depths of 1000ft. However, it finds it difficult to drill through rock and the drilling fluid makes it difficult to determine if the underground water has been struck.
Augers drill using rotating buckets or continuous stems and they can be operated manually or using power. They are best for clay soils and can reach up to 20 ft. when powered manually or 125ft. when using power equipment.
• Cable Tool Drilling
Cable drills have bits, which move up and down a cable smashing and pulverizing the ground as they drill into the ground. They use water to loosen the ground and can reach similar depths as the auger drills. They are suited for drilling into rock but are costly and the well drilling process is slower compared to other drilling methods.
• Other methods include using strong water jets and hand driving which is best suited for well drilling from shallow water tables.
The Structures of a Well
After digging the hole, the well needs additional structures that will ensure that the water pumped up is free from sediments that will mean minimal purification will be done on the water. The following are the steps taken to achieve this
• The Casing
The casing lines the hole and the most common material used is PVC, it prevents contamination of the water as it moves up the well. Installing vents and an insect and weatherproof cap will prevent contaminants from the surface getting into the well. The casing can also be used to house the pump.
• Putting a Wall Screen
A well screen is used in gravel or sandy aquifers and it acts like a sieve preventing the sand and gravel traveling up with the water from the ground. The size of the screen is determined by the size of sand and gravel particles in the well. To prevent fine sediments from filtering through the screen and getting into the water, a gravel pack can be used. The gravel pack is an envelope of sand or gravel placed between the screen and the well wall and it traps the fine sediments preventing them from getting into the water as it travels up after being pumped.
• Using Grout
Well drilling using the rotary method creates a hole with a large diameter, which causes a space to be created between the casing and the walls of the hole. This space is called an annular space that must be sealed to prevent ground water from flowing into the well. Grout is the material used to seal this space and it is commonly made up of a mixture of water and cement although any other suitable materials may be used.
• Developing the Well
Developing the well is the final step and involves removing mud and sediments from the bottom of the well to facilitate uninhibited movement of water from the ground to the surface. This can be achieved using different methods such as pumping water at high speed out of the well or injecting water or air into the well.
Planning Before Drilling a Well
When drilling the well it is important to involve all the necessary consultants such as surveyors, hydrologists, and geologist because they will guide you on the best methods to use as well as the best location to drill the well. All drilling should also follow the state regulations as well as the environmental and safety regulations. Additionally, one should obtain all the required permits. It is also vital to have a detailed plan before drilling because this will assist you to calculate the costs of the project and you will be in a better position to work within the planned timeline.
Wells offer a great way of meeting water requirements at an affordable rate and they can be a source of clean uncontaminated water that requires minimal purification before consumption.