Core barrels are available in various types and standards, with the selection depending on factors such as formation characteristics, drilling depth, hole diameter, and drill rig capabilities. Common standards include ISO 3552-1992 (e.g., Single B, Double T2) and ISO 10097-1:1999 (e.g., wireline systems). Additionally, several non-standard types like T6, T6S, and Geo-line are widely used across the industry.

In conventional core drilling (ISO 3552-1992), the process involves adding drill rods as the borehole advances. Once the core barrel is full—typically every 3 meters—the entire drill string must be withdrawn to retrieve the core, then reinserted with an added rod to continue drilling. This repeated extraction and reinsertion increases non-productive time as depth increases, which in turn raises the cost per meter of drilled core.