What does the annular space refer to?

The annular space refers to the gap between the borehole wall and the well casing. This space is critical in well construction and operation as it allows for the proper installation of the casing to support the borehole structure and protect the aquifer from contamination. It also serves various functions in the drilling process, such as enabling the circulation of drilling fluids and allowing for the placement of grout or sealants to prevent the migration of water between different geological layers.

Understanding the importance of the annular space is essential for ensuring the integrity of wells and optimizing the extraction of groundwater resources while minimizing environmental risks.