The bottom-hole assembly (BHA)
is the component of the drill string
that includes the core bit, outer
core barrel, various subs, and the
drill collars. It hangs below the
drill pipe and provides weight to
the drill or core bit to induce the
teeth to penetrate the formation,
thereby drilling a hole or recovering
core to meet the scientifi c
objectives of the cruise. The Ocean
Drilling Program (ODP) employs
different coring tools to obtain
continuous, relatively undisturbed
cores in all types of oceanic sediments
and igneous basement.
ODP uses three primary coring systems,
each with a different BHA:
• The Advanced Piston Corer
(APC) and Extended Core Barrel
(XCB), which use the same BHA;
the Pressure Core Sampler (PCS)
and Motor-Driven Core Barrel
(MDCB) are also compatible
with this BHA (note: the MDCB
needs an additional sub when it
is run);
• The Rotary Core Barrel (RCB),
and
• The Advanced Diamond Core
Barrel (ADCB).
The bottom-hole assembly (BHA)is the component of the drill stringthat includes the core bit, outercore barrel, various subs, and thedrill collars. It hangs below thedrill pipe and provides weight tothe drill or core bit to induce theteeth to penetrate the formation,thereby drilling a hole or recoveringcore to meet the scientifi cobjectives of the cruise. The OceanDrilling Program (ODP) employsdifferent coring tools to obtaincontinuous, relatively undisturbedcores in all types of oceanic sedimentsand igneous basement.ODP uses three primary coring systems,each with a different BHA:• The Advanced Piston Corer(APC) and Extended Core Barrel(XCB), which use the same BHA;the Pressure Core Sampler (PCS)and Motor-Driven Core Barrel(MDCB) are also compatiblewith this BHA (note: the MDCBneeds an additional sub when itis run);• The Rotary Core Barrel (RCB),and• The Advanced Diamond CoreBarrel (ADCB).
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