Well Drilling Methods
Historically, well drilling has been associated with digging deep into the ground to reach water sources. In the past, operators may have used a large conventional rig to bore a hole. These days, well drilling contractors use a variety of methods to drill a well. The methods vary depending on the type of well that is being drilled and the area where it will be placed. In some areas, wells are drilled to a depth of over 500 feet.
The goal of well drilling is to reach an aquifer deep beneath the earth. This requires a heavy bit that is raised and dropped into the ground repeatedly. The bit loosens the earth and allows for the formations to be drilled. The hole may be open or may be in bedrock. The bottom portion of the hole may be filled with gravel to stabilize the well assembly.
Once the hole is drilled, it may be filled with cement to seal it. The well is usually lined with a screen to filter out gravel. This screen is made of stainless steel or other material. It keeps sand out of the well and allows for maximum water flow. The screens are also used to prevent contaminated water from entering the well. Some well drilling contractors install the screens before drilling the hole.
The screens in the casing may be made of various materials, such as stainless steel, concrete, or slotted PVC pipe. The screen material depends on the type of formations encountered during drilling. It allows water to flow into the well without being contaminated by gravel and sand. The screen may also be drilled a few holes through the casing to allow for additional water flow.
Depending on the formations that are encountered during drilling, the well may need to be drilled in a pattern. The most common pattern is the line drive. In this pattern, the drilled hole is usually an inch or two wider than the casing. The formations are drilled into with the intent to produce oil or natural gas. This pattern can be used to increase yield in low-yielding wells.
Another common method is the open hole casing method. This is used only in areas where granite or dolomite is found. Its disadvantages include the possibility of a short supply of water and the possibility of leakage from the surrounding formations. This method is used in areas where the water supply is only expected to last a few years.
The most common materials used for casings are concrete pipe, plastic pipe, and galvanized steel. The well drilling company may install the casing before or after drilling. They may also use a variety of other techniques to complete the well. The company may use a rotary drilling machine or a “pounder” machine to drill the hole. The pounder machine method is slower than the rotary method, but has been used to drill millions of successful wells around the world.
