Drilling Theory

Luke Jackson Director Business DevelopmentDeepcore Drilling

1. Cable tool 2. Auger3. Air Drilling

1. RAB Rotary Air Blast (Air Rotary)2. RC (Reverse Circulation)

4. Mud Rotary5. Diamond6. Other

Drilling Safety1. Always ask the driller before entering a drill site.2. All visitors to be inducted at the drill rig3. Be aware of:

1. Noise 2. Rotating parts (do not go near the spinning rods)3. High pressure air 4. Water / mud Sumps5. Water and sample discharge (hoses and Cyclones)6. Movement of drill rods from Rod trailer / truck to the mast7. Rod Handler (can move without warning)

Drilling Theory

Type Depth Cost Sample QualityCable Shallow Very Cheap GoodAuger Shallow Cheap Poor / goodRAB Shallow medium Cheap PoorRC Hundreds of meters Medium GoodMud Rotary Kilometres Medium PoorDiamond Kilometres Expensive Excellent

Drilling Terms RC Reverse Circulation RAB Rotary Air Blast Diamond Core drilling using drill bits with diamonds Mud a liquid drilling fluid used to suspend rock fragments DTH Down the hole BOP Blow out Preventer (Annular Diverter ) Kelly Rod Top rod (with water swivel attached) Reaming widening the hole Hole Conditioning Ensuring adequate wall cake PCD (PDC) Polycrystalline Diamond (Compact)

Cable Drilling4000 years old used in China to drill to over 1000mAlso called:

Pounders, percussion, walking bean rigs, Banka drill, grab or clam shell drilling

Auger Drilling

Air Drilling Began in the 1860s (popular in the 40s and 50s) Standard / Conventional Reverse Circulation

Dual Pipe

High Pressure air to lift rock fragments to the surface

Samples can be subject to contamination

Cyclone needed to separate air from the rock chips

Air DrillingAir Core Shallow drilling Good for sand and unconsolidated material

RAB Rotary Air Blast Generally shallow Drill to refusal Low quality samples

RC (Reserve Circulation) First RC rods made in Kalgoorlie in 1972 RC Hammer developed in 1990 Very high air pressure required for deep holes in hard rock

Air Drilling - Bits Roller Blade

Soft formations Good for heavy clay Drill to refusal

Hammer (Percussion)

Hammers Hammer

RC - air goes AROUND the bit and back into the bit with the sample

Conventional hammer - air flows through the bit then up the outside of the drill string

Bit does not lift and strike the rock, force is transferred through either a:

Top Hammer DTH Hammer

Uses compressed air to drive the hammer

DTH Hammer Hammer

RC - air goes AROUND the bit and back into the bit with the sample

Conventional hammer - air flows through the bit then up the outside of the drill string

Bit does not lift and strike the rock, force is transferred through either a:

Top Hammer DTH Hammer

Uses compressed air to drive the hammer

Mud Rotary1901 Steam engine used with mud to penetrate and lift cuttingsMud used is normally bentonite or Barite

Diamond Core Core drilling was invented by the Egyptians 5000 years ago Diamond Drill bit Industrial diamonds set into a soft

metallic matrix Core is cut, broken at the face of the bit and a core

extracted Conventional All rods are removed with the core Wireline Inner tube is used to extract the core

leaving the rods and drill bit in the hole

Core lifter is used to hold the core in place

Diamond Core Core Barrel

Driven by the outer tube Bit and Reamer

Stationary Inner Tube Core lifter Head assembly and swivel Shut off valve (Stop coring) Ball check valve (Fast decent) Thrust bearing and compression spring Spear Point

Overshot Lifting dogs and swivel

Drill rod sizesSize Hole (outside)diameter, mm

Core (inside)diameter, mm

AQ 48 27

BQ 60 36.5

NQ 75.7 47.6

HQ 96 63.5

PQ 122.6 85

Other Drilling Types Sonic

50-150 hertz (cycles per second) Hydro Jet

High pressure Superheated water Dual Rotary Drive

Drill casing and rods Flame Jet

Hydrogen flame at 4000 Degrees C

Traps for young players Dont drill flat holes with a percussion rig Learn about the drill you are working on, Ask the driller

questions. The drillers know that you dont know how a drill works.

If you have the opportunity work on a rig as an offsider / fieldy When using a cyclone use a good quality rotary splitter High pressure water will restrict the use of down hole tools

(Survey / Navi etc), especially in up holes.

Kola superdeep borehole Project started in 1962 planned to reach 15,000m (moho) Drilled from 1970 1994 12,262m deep diamond core hole Part of the Space race between USSR and USA Drill bit turned and rods stayed still 180 degrees at depth where the

rocks behaved like plastic

Slide Number 1Drilling TheoryDrilling SafetyDrilling TheoryDrilling TermsCable DrillingAuger DrillingAir DrillingAir DrillingAir Drilling - BitsHammers DTH HammerMud RotaryDiamond CoreDiamond CoreDrill rod sizesOther Drilling TypesTraps for young playersKola superdeep borehole