What is the purpose of gravel packing a well?

The purpose of gravel packing a well is primarily to allow larger well screen openings to be used effectively. By surrounding the well screen with gravel, which is typically coarser than the formation material, the gravel acts as a filter to prevent fine particles from entering the screen. This enables the use of larger openings in the well screen without risking the accumulation of silt or sand, thereby maintaining the flow of water into the well while ensuring the longevity and efficiency of the well system. The gravel pack stabilizes the formation around the well and enhances the overall water extraction process.

The other options do not accurately represent the purpose of gravel packing. For instance, gravel packing does not decrease the water yield; rather, it can help maintain or even enhance yield by ensuring flow from the aquifer. It does not inherently improve water quality but instead helps prevent the ingress of sediment, which can impede quality; improvements in quality are more a secondary effect. Additionally, gravel packing does not increase static water levels; the static water level is determined by the aquifer conditions and the well's drawdown effects, rather than the gravel arrangement.