The purpose of performing sieve analysis of sands and gravels in monitoring well construction is to determine what?

• A. Backfill material
• B. Screen slot opening
• C. Water yield
• D. Drilling mud type

Answer: (B)

The key idea is matching the screen to the surrounding formation. Sieve analysis reveals the size distribution of the sands and gravels around the well, showing which grain sizes are most common. With that information, you pick a screen slot opening that will keep the larger grains (and potentially fines) from entering the well while still allowing water to flow freely. If the slots are too large, sediments can clog the screen; if they’re too small, water flow is restricted and the gravel pack can become packed or ineffective. The other options don’t directly relate to selecting the screen size: backfill material is governed by overall gradation, water yield depends on aquifer properties, and drilling mud type is a drilling-fluid issue, not a screen sizing issue.