Well inspection and cleaning are a critical process that involves a variety of procedures to ensure the well’s optimal performance. However, in Costa Rica, there appears to be a standardized approach to well cleaning that involves simply pulling the pump and blowing the well with compressed air. This approach may be suitable for rehabilitating the well, but it is not the correct method for cleaning and developing a water well. Ideally, water wells should be cleaned at least once every five years.
Here is a step-by-step procedure that we use for any well cleaning project. It is essential to note that the cleaning and development process depends on the problems identified during the primary inspection of the water well.
Step 1: Removal of Well Pump
The well pump will be removed from the existing water well. The pumping system will be thoroughly inspected, and a detailed report will be produced based on the inspection results.
Step 2: Well Inspection using Down the Hole Camera
After the well pump has been removed, we will proceed to inspect the water well using a dual camera system. This camera operates with two different cameras that serve distinct purposes.
The first camera is designed to inspect the area directly below the probe as it is lowered into the well. This camera provides a real-time visual display of the oncoming details in the well, such as any obstructions or sediment buildup.
The second camera is used to identify defects or other pertinent information that may impact the well cleaning procedures. This camera can rotate 360 degrees in either direction, providing a high-resolution image of the well’s interior. It is particularly useful for identifying cracks, fractures, or other damage that may have occurred over time.
By using this dual camera system, we can accurately identify any issues within the well and develop the appropriate cleaning and maintenance procedures to ensure optimal performance. This step is crucial to ensure that the well is thoroughly inspected before any cleaning or maintenance work is carried out.
Step 3: Well Cleaning using Dual Swab Method
Water well cleaning and development is a process that involves removing fine materials and mineral deposits from the formation to ensure that the well is producing clean water. There are two common development methods used in this process, which are airlift and mechanical surging. These methods are often combined to achieve the desired results.
During the process, a double surge block assembly is attached to the drill pipe and rapidly raised and dropped to create turbulence in and around the screen. At the same time, water is lifted with air inside the drill pipe from the development zone, which is isolated by the two surge blocks, also known as “packers.” This technique is illustrated in the accompanying diagram.
As the assembly creates turbulence, the water becomes free of sediment, and the assembly is lowered to the next section of the screen. This process concentrates the development energy on short sections of the screen and aquifer, making it particularly effective.
This dual swab method vacuums the screened interval of the water well while also providing a swabbing or plunging action of the screened interval to mechanically remove sediments and minerals from the well. Additionally, various chemicals and additives may be introduced during the cleaning process, depending on the specific problems encountered.
Typically, the cleaning process takes between 8 and 16 hours of mechanical surging and well evacuation to complete. Overall, this process is an essential aspect of maintaining a clean and reliable water source for domestic or commercial use.