How deep are samples typically taken during formation sampling?

Formation sampling is a critical process in hydrogeology and groundwater studies that involves taking samples of subsurface materials to analyze the characteristics of the geological formations. The depth intervals at which samples are taken can vary based on the specific objectives of the sampling and the expected geological conditions.

The practice of taking samples every 5 feet down to 200 feet is commonly adopted because it balances the need for detailed stratigraphic information with efficiency in terms of time and resources. This frequency allows for a thorough assessment of the geological layers, capturing variations and potential zones of interest without excessive sampling that could increase costs and practicality of the operation.

This approach is particularly useful in aquifer studies or when investigating potential contaminants, as it ensures that a representative sample is gathered across different depths, enabling better understanding of groundwater flow, saturation levels, and geochemical properties.

Other depths and frequencies may be adequate in specific scenarios but using a 5-foot interval is a standard method in many hydrogeological investigations, particularly when dealing with more complex stratigraphy where variations can occur over short vertical distances.