Coring System Bits
There are three coring systems. Each uses different bottom-hole assemblies (BHA) and types of core bits:.
I. Advanced Piston Corer (APC) (see the APC tool sheet) and Extended Core Barrel (XCB) (see the XCB tool sheet) (both systems use the same BHA),
II. Rotary Core Barrel (RCB) (see the RCB tool sheet), and
III. Advanced Diamond Core Barrel (ADCB) (see the ADCB tool sheet).
The BHA for each coring system is slightly different, but in general consists of a primary core bit, outer core barrel (OCB), short sub assembly, and drill collars. The OCB supports the wireline retrievable inner core barrel, which receives and carries the core. Drill collars are heavyweight pipes that apply weight to the bit on the bottom of the OCB. The BHA is run on the drill pipe string, which is rotated at the surface to drive the bit (except the Motor-Driven Core Barrel [MDCB]) and advance the BHA (see the BHA tool sheet for more information). The MDCB and Pressure Core Sampler (PCS) are compatible with the APC/XCB BHA.