Geological Exploration & Core Drilling

Protect the information value of the hole

Geological and core drilling is often evaluated by sample quality, core recovery, interval identification and borehole control as well as penetration. The bit, barrel, drill string, fluid program and operating practice must support the information objective of the project.

Describe the sampling requirement

State whether the project requires continuous core, selected core intervals, cuttings, or simply a pilot hole. Include the target core diameter, barrel type, expected broken zones and any restriction on flushing media. These details can change the suitable bit and connection.

Relevant tool groups

• PDC core bits: reviewed by formation, face geometry, waterways, core opening and barrel compatibility.
• Coreless PDC bits: considered when a full-hole drilling objective is more important than retrieving core.
• Tricone bits: used as an option in suitable rotary intervals after formation and operating inputs are defined.
• Drill rods, subs and couplings: specified by exact thread, outside diameter, wall, length and the complete string interface.
• Exploration rigs: evaluated by depth capacity, feed, pullback, rotary range, mast stroke, mobility and the planned drilling method.

Information to prepare

• Hole depth, diameter and inclination
• Core or cuttings requirement and target recovery
• Formation sequence, fracture and abrasiveness
• Rig, pump, barrel and current drill-string models
• Connection drawings or clear thread measurements
• Quantity, destination and required documentation

Evaluate results in context

Core recovery and tool life should be reviewed together with formation changes, run length, bit condition and operating records. The published PDC coring case provides a comparison structure, not a guaranteed result for a different geological program.