An Overview - aig.org.au Overview - Most Commonly ... Potential mess on completion, ... Mud rotary...

AIG‐ADIA Drilling for Geology seminar 1/8/2014

1

An Overview -Most Commonly Utilised Drilling Methods and their Applications within Australia

Welcome and Introduction


2

Overview Drilling Industry Sectors

Fundamentals of Drilling a hole

Drilling Methods

Drilling Rigs

Summary of Drilling Methods and their Applications

Drilling Industry Sectors Geotechnical Foundation / Construction Mineral Exploration Blast Hole / Seismic Water Well Environmental Oil and gas Over Water and Offshore


3

Why do you need to drill a hole? What are you hoping to achieve –

• Detailed geology or Basic overview?• Sample retrieval?

• Type of sample – soil / core?• Disturbed / undisturbed?• Size of sample?• In-situ testing?

• Installing monitoring equipment?• Simply a hole eg. for foundations • How deep?• What diameter?• Where….?

Drilling Fundamentals Drilling or penetrating the ground effectively

Effective clearing of the hole

Stable walls

Information Gathering Techniques –

Applications requiring coring / sampling

Well construction applications


4

Drilling Methods Auger drilling – solid flight / hollow stem

Washbore / Mud Rotary Drilling

Coring – Conventional and Wireline

Sonic

Direct Push

Air Rotary - RC – Reverse Circulation

RAB – Rotary Air Blast / Percussion /Hammer

Auger Drilling Piling – large diameter, soft

ground Geotechnical - Generally only

used for shallow holes <10m Solid Flight Hollow Stem – continuous

undisturbed samples Can come in a variety of sizes

– 50mm and up Tungsten Carbide bit (TC) Will refuse in large and tight

gravels, cobbles, boulders and rock.

No drilling medium needed


5

Washbore / Mud Rotary Used in geotechnical drilling and

for deeper holes in unstable strata

Water is the drilling flush/medium to help bring cuttings to the surface

Drilling muds / additives are added to help hole advancement and stability

Suitable for un-consolidated and some low strength consolidated formations

Variety of bit types Water is generally recycled by

way of tanks or pits Potential mess on completion, Can be harder to log strata

Coring Best applied in consolidated

formations

Various sizes – eg. NLMC, HQ, PQ

All hole depths

Wire line coring – can be faster than conventional coring depending on depth and strata

Ideal for samples for strength testing and detailed logging

Air and water can be used as a medium

Can be slow depending on strata and depth


6

Sonic Drilling Rotary vibratory drill Liquefaction of soils and

overburden – utilised in unconsolidated and consolidated materials including boulders

Continuous samples – soil and rock.

In rock water is added to speed up the drilling

Fast – 10m / hour Minimal sample loss Quiet Minimal waste Relatively new technology Potential alteration to borehole

permeability Limited depth range

Direct Push No Cuttings

Undisturbed samples

Fast – 2-8m per minute

Smaller diameter holes

Small rigs – useful for difficult / tight access

Probe attachements also available – similar to CPT probe

Limited depth range

Only suitable in unconsolidated ground


7

Air RotaryCommon in exploration and water drilling• Fast• Chip samples only• Suitable in both unconsolidated and

consolidated formations• Easy to determine water strikes• Water and additives can be added

to aid drilling and stabilise the holes• It is possible to erode the borehole

wall and samples are more easily contaminated

RC -Reverse Circulation – cuttings lifted out of the hole up the drill string –Fast Cuttings contained Better quality –less contaminated

RAB – Rotary Air Blast / conventional circulation Fast Can be messy

Efficiency – Which rig and technique should I use?Which Method will get me the results I need- quickly, is most cost effective but without loosing quality?

Factors to consider: Strata Depth and diameter – will casing need to be run? Samples – frequency and type Budget Site constraints


8

Unconsolidated Formations

Auger Drilling –Cheap and fast

Rotary Mud – Fast penetration rates

Rotary Air – Very fast in dry cohesive formations

Firm but stable formations – high

drillability

Rotary Air / Mud –good results

Hammer – Chip and water sampling, fast penetration

Diamond Coring –Slower than hammer but V good samples

Consolidated –Low drillability

Hammer – fast penetration (Top hole hammer – shallow holes, down hole hammer deeper holes)

Diamond Drills – more info + core

Rotary – fast and cheap

Drilling Boulders and difficult ground

Casing advance systems

Hammer – breaks boulders up

Sonic - drills straight through obstructions


9

ExamplesGeotechnical hole:Sampling every 1.5m Utililsing Auger, wahsbore and coring Expect 20-30m a day on averageExploration open hole:Mud/Air RotaryChip samples every 1.0mExpect 60 – 200m a day depending on casing requirements and hole diameterSonic Hole:Continuous sampleUp to 10m an hour

In each case the speed is often dictated by the ground conditions and size of the drill rig and the drillers experience.

Quality

Right rig for right job

Experienced and licensed driller and crew

Time

Well maintained equipment

Budget


10

PriceMany factors to consider: Depends on the drilling application – Techniques do

affect cost-• Geotechnical – less meters in a day = higher meterage

rate and more items• Exploration – more meters achievable in a day = lower

meterage rate Details of the job – mine site, brownfield or greenfield

site, access, distance between holes etc etc… all must be factored in when pricing a job.

Size of the drill rig

Meterage V Day Rate - Day Rate Client takes on the risk meterage the driller takes the risk

Auger RigsSmall to large in size, variety of carriers

The larger the auger the larger to rig

Most multipurpose rigs also have auger capabilities as do some excavators – various diameters –can be an alternative to test pits on restricted access sites

4x4 mounted rigs often used for shallow Geotech investigations


11

Comparison

Solid Flight Hole must support

itself Cuttings are bought to

surface by the helical flights

Low equipment costs and set up

Accurate water strikes

Hollow Stem Secondary internal rod

therefore hole is continually supported

Wireline and overshot commonly used to retrieve samples and run testing equipment

Higher cost to set up than solid flight

Slower than solid flight

Rotary Air /Mud

Truck or Track MountedGenerally large in order to be able to drill deeperCan be multi – purpose - auger, washbore and coreSome are purely air rotary sucj as the RC rigs (not common in QLD – more often used for heavy metal / mineral exploration)

Most common applications –exploration, geotechnical, environmental monitoring, water well


12

Comparison 2

Mud Rotary Mud helps stabilise the

hole – less erosion of bore walls

Lifts cuttings / samples quicker to surface

Helps keep bit cool and cutting action cleaner

Preferred on gas sites

Air Rotary Better in consolidated

ground Fast More equipment –

compressors Better quality samples

– can be easier to log

Sonic and Direct PushSpecialised methods Truck or track mountedVarious sizes and appearances –similar to muti-purpose rigs in appearance – have a different head assembly.May require less support

equipment than conventional drill rigs

Not as common as conventional drill rigsApplications – Geotech, Environmental and difficult drilling – boulders, landfill etc.


13

The Geologist’s Role on Site Give information and instruction to the driller –

COMMUNICATION IS KEY!

Understand the drilling method and understand the basic principles of drilling a hole

Understand the sampling methods and procedures

Try not to p**s the driller off!!!!

Summary Auger – geotech, piling, shallow investigations

Mud rotary – geotech, deeper unconsolidated formations, exploration gas sites, offshore

Air Rotary – consolidated formations, environmental, exploration, water well, blast holes and seismic

Direct Push – shallower environmental investigations, geotech

Sonic – geotech, environmental investigations


14

Summary The best drilling method depends on the type

of job and results that are needed

Every hole is different

Communicate clearly what you expect from the investigation

Cheapest and quickest method may not save you money in the long run

More information Speak with drilling companies direct

Get in touch with ADIA

Reading material “Drilling The Manual of Methods, Applications and Management” Produced by Australian Drilling Industry Training Committee Limited


15

Any Questions?

An Overview - aig.org.au Overview - Most Commonly ... Potential mess on completion, ... Mud rotary...

Documents

Transcript of An Overview - aig.org.au Overview - Most Commonly ... Potential mess on completion, ... Mud rotary...