Key points of quality supervision during well drilling construction

Key points of quality supervision during well drilling construction

On-site supervision during the well drilling process can effectively prevent construction oversights and ensure the water quality, quantity and service life of the final well. The following is a summary of the quality points that you should focus on in the key aspects of well drilling.

1. Early preparation and positioning supervision

Confirm the construction plan: clarify with the construction party key objectives such as drilling depth, diameter, casing material and specifications, and expected water production levels. Ask them for their recommended well depth and configuration based on local experience.

Check equipment and materials: Check whether the drilling rig model on site meets the predetermined construction requirements. Check whether the well pipe (casing) is a new or intact thickened PVC pipe/steel pipe, and the pipe wall has no cracks or deformation. The pore size and distribution of the water filter pipe (flower pipe) should be uniform and can effectively retain sand.

Supervise wellhead positioning: ensure that the drilling point is away from septic tanks, sewage ditches, livestock pens and other pollution sources (at least a horizontal distance of more than 30 meters), and consider the convenience of future use.

2. Core supervision points in the drilling process

Follow up the whole process and record the strata: The construction party is required to simply record the conditions of the soil, sand and rock strata excavated at different depths (photographs can be taken for storage). This not only verifies their professionalism, but is also a key basis for judging which layer of water-bearing sand layer the water filter pipe should be placed in, which is crucial to the quality of subsequent well formation.

Check the verticality and hole diameter of the well: observe whether the drilling process is smooth and whether there is serious shaking. The completed well hole should be as straight as possible with uniform hole diameter to ensure that the well pipe can be lowered to the bottom smoothly.

Supervise core sampling (such as deep wells or bedrock wells): If you need to drill into rock formations, you should check the core samples taken out to confirm the rock hardness and fracture conditions to determine whether they are consistent with expectations.

3. Quality control points for running pipe, gravel filling and cementing

This is a key step that determines whether the well can produce clean water for a long time without collapsing or causing contamination. It must be supervised on site throughout the process.

Supervise the pipe-laying operation: Check whether the well pipe connection is firm and sealed, and ensure that the water filter pipe (flower pipe) section is accurately lowered to the previously recorded water-bearing sand layer position, and the actual pipe part corresponds to the water-isolating layer. The pipe running process should be slow and steady to prevent the well pipe from breaking or getting stuck in the well.

Supervise gravel filling: The annular space between the well pipe and the well wall must be filled with clean and uniform coarse sand or special quartz sand filter material (gravel). Supervise the construction party to continuously and evenly fill in from all sides to ensure that the filter material is filled in place to form an effective filter layer and prevent fine sand from flowing into the well.

Supervise cementing and sealing: After the filter material is filled to a predetermined height, the top must be tightly sealed with high-quality bentonite or clay balls until it is filled close to the ground. This is to prevent surface sewage from seeping down along the outer wall of the well pipe and contaminating the groundwater. This step must not be omitted or replaced with soil at will.

4. Acceptance process of well cleaning and water testing

Supervise thorough well cleaning: After the pipe is filled with gravel, a submersible pump or air compressor must be used to clean the well for a long time and with high intensity until the pumped water becomes completely clear and free of sand. Incomplete well cleaning is the root cause of long-term muddy water in wells.

On-site water test acceptance: measure the still water level depth. Then conduct a continuous pumping test lasting at least several hours to observe whether the water volume is stable and sufficient, and whether the water level can recover stably after it drops. At the same time, use a clean container to collect the water sample. Visual inspection should be clear and transparent, without impurities and odor.

Summary suggestions: Keep certificates during the process and pay step by step

As an owner, the core of supervision lies in on-site confirmation of key steps. It is best to take photos or videos for retention of the depth of pipe running, gravel filling and isolation materials, well cleaning effects and other aspects. The payment method can be linked to the construction progress, and the corresponding payment will be made after the quality of each step is confirmed. A detailed construction record and final well structure drawing should be delivered to you together with the final payment. Although strict supervision requires time, the reward is a reliable and good well for the next ten years, which is definitely worth it.