Key Points for Quality Supervision During Drilling Construction

Key Points for Quality Supervision During Drilling Construction

In drilling construction, effective on-site quality supervision is crucial to ensuring sufficient water yield, excellent water quality, and a long service life for the well. As the owner, you don't need to understand all the technical details, but you must grasp the following core supervision points.

I. Pre-Construction Supervision: Confirming the Plan and Materials

Confirm the construction plan: Clearly define key objectives with the contractor, such as drilling depth, diameter, well casing material and wall thickness.

Material acceptance inspection: When well casings, filter pipes, and filter materials (gravel) arrive on site, you must personally inspect them. Check the well casings for cracks or deformation; ensure the filter material is clean and uniform, not a mixture of mud and sand.

II. Drilling Process Supervision: Recording the Actual Strata

Request and review the "strata record": This is one of the most important supervision aspects. Require the contractor to briefly record the soil layers, sand layers, pebble layers, or rock layers encountered at different depths (preferably with photographic documentation). This record is the scientific basis for determining the location of the aquifer.

III. Supervision of Critical Well Completion Procedures (Must be present throughout)

This stage determines the success or failure of the well and requires close supervision.

Casing installation supervision: Ensure that the perforated casing section is accurately lowered to the previously recorded aquifer sand layer location, not into an impermeable clay layer.

Gravel packing (filter material placement) supervision: Clean coarse sand or quartz sand filter material must be uniformly and continuously filled into the annular space between the well casing and the well wall. The excavated soil must never be used for backfilling. This is crucial for forming a natural filter layer and preventing sand production.

Sealing (cementing) supervision: Above the filter material layer, a tight and solid seal must be created using high-quality clay balls or bentonite, extending almost to the surface. This step is vital for preventing surface water infiltration and ensuring water source safety; it must never be omitted.

IV. Completion Acceptance Supervision: Based on Results

Supervise thorough well cleaning: After casing installation, the well must be thoroughly cleaned for a long period and at high intensity until the pumped water is completely clear and free of sand. Incomplete cleaning is the main cause of cloudy water.

On-site pumping test:

Measure the static water level depth.

Conduct continuous pumping for at least 4-6 hours to assess whether the water yield is sufficient and stable. Collect water samples at the site using clean containers. Visually inspect the water quality; it should be clear, free of impurities, and odorless.

V. Effective Payment and Document Exchange

We recommend phased payments: link project payments to key milestones (e.g., 30% upon commencement, 30% upon material delivery, and the remaining 40% after successful well testing). This is an effective leverage to protect your rights.

Request completion documents: Ask the contractor to provide a simple well completion report, including at least a well depth structure diagram, a brief description of the geological layers, static water level, and a list of materials used.

Summary: Focused Supervision and Documentation

Your supervision should focus on seven key points: material acceptance, geological layer records, filter pipe alignment, filter material filling, sealing and water stoppage, well flushing water quality, and final water yield. Take photos or videos of critical procedures as evidence. Through clear, focused supervision and performance-based payments, you can maximize your chances of obtaining a qualified and durable well.