HKIE Civil Division - Technical Seminar

Application of Horizontal Directional Drilling

(HDD) Technique in Hong Kong(HDD) Technique in Hong Kong

28 January 2013

Creating

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Mr. MP CHAN

Ir. Neil WONG

Ir. Vincent CHAN

Contents

1. Current Application of HDD in Hong Kong

2. Advanced HDD Guidance System

3. Advanced HDD Drilling Method

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4. Potential Application of HDD in Hong Kong

5. Example of HDD Application in Hong Kong –

Submarine Outfall of Sewage Treatment Plants in

Lamma Island

6. Difficulties of Lamma HDD Project

7. Q & A Creating

Solutions

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Current HDD Application in HK

� Water pipes

� Electric cable ducts

� Gas pipes

� Sewage pipes

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� Sewage pipes

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Horizontal ties installation

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Submarine outfalls installation

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Advanced HDD Guidance System

� Basic components of Paratrack II guidance system:

� Steering tool probe

� Drillers console interface

� Power guide supply

� Computer

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Computer

� Accuracy: +/- 2% of vertical depth of hole

� Capable of working over 300m depth

� Can work with Earth magnetic field and artificial

magnetic field

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Basic System

� Working on Earth magnetic field

� Continuous display of Azimuth, Inclination and Tool Face Angle readings

during drilling (MWD)

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Basic System

� Alignment of mudmotor bent-sub and Paratrack steering

tool probe “Tool Face Angle”

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Basic System

� Electric wire connection

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Basic System

� Paratrack II computer display during drilling

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Advanced System

� Guide Wire Tracking

� Working on artificial magnetic field, not affected by magnetic interference

� Display of electric wire loop on the PII computer display

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Electric Wire Loop Method

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Recent job reference in HK

� Lamma - YSW hole trajectory

� 0.6m from the target on plan after drilling 551m

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Recent job reference in HK

� Lamma - SKW hole trajectory

� 1.7m from the target on plan after drilling 762m

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Magnetic Source Method

� For sites with the following constraints: -

� Ground surface are with busy roads or private building lots etc.

� There is only one end access of the hole(s).

It is impossible to install guide wire loop to perform

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� It is impossible to install guide wire loop to perform

“Guide Wire Tracking”

� The magnetic source must be with known position reference

� High precision, centimeter accuracy

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Magnetic Source Method

� Magnetic Guidance

Tool (MGT) Technique

� Passive Magnet

Ranging (PMR)

� Micro-Coil Technique

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Ranging (PMR)

Technique

� Rotating Magnet (RM)

Technique

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Gyro Steering Tool (GST) Method

� High precision optical gyroscope

� 0.2m deviation for 300m drilling length, 0.7m for 1000m hole

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Parallel Drilling

� Parallel drilling using the MGT guidance method

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Intersect Drilling� Intersect drilling using the Magnetic Source guidance method

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Ground Freezing Hole Drilling

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Sacrificial Hole

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Grout Hole Drilling for Tunnel Works

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Grout Hole Drilling for Tunnel Works

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Drainage Hole Drilling for Slope Works

� Drainage of moving slopes

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Potential Application of HDD in HK

� Just add a bit imagination plus some creative

and innovative ideas, you should be able to

think of other potential HDD applications in HK.

� Lastly, new methods require prudent approach

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� Lastly, new methods require prudent approach

to make it work!

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Example of HDD Application

in Hong Kong

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� Lamma Island - an outlying island without any centralised

public sewerage systems at present

� Individual house owners still using septic tanks and soak-

Project Background

� Individual house owners still using septic tanks and soak-

away system for sewage treatment

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� Some septic tank and soak-away systems do not function

effectively due to site limitations and lack of regular

maintenance

Project Background

� Construction of village sewerage network systems and

sewage treatment works at both Yung Shue Wan (YSW) and

Sok Kwu Wan (SKW) is necessary

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Project BackgroundConstruction of Sewage Treatment Works (YSW & SKW)

Contract No. DC/2009/13

Client Drainage Services Department

Consultants Scott Wilson CDM Joint Venture

Main Contractor Leader Civil Engineering Corporation Limited

HDD Specialist VSL Intrafor HK

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Submarine

Outfall Pipe

Corals

Diffuser

Yung Shue Wan (YSW) Works

Sewers

Works under DC/2009/13

Legend:Yung Shue Wan

Sewage Treatment

Plant Existing Sewers

Corals

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Submarine

Outfall Pipe

Diffuser

Sok Kwu Wan (SKW) Works

乡村污水收集系统第1阶段工程污水处理厂建造工程

魚類養殖區

Existing Sewers

Works under DC/2009/13

Legend:

FCZ Fish Culture Zone

Sok Kwu Wan Sewage

Treatment PlantPumping Station No.2

Pumping

Station

No.1

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Comparison of Construction Methods for

Submarine Outfall

Dredging Method HDD

Majority of existing corals will be lost Existing corals would not be affected

Existing Fish Cultural Zones (FCZ) may be affected.

Existing Fish Cultural Zones (FCZ) would not be affected during may be affected. would not be affected during

construction by HDD

Dredging and disposal of large amount of materials required

Only small amount of dredged materials will be generated

Complaints about sediment and chemicals release during large-scale

dredging works

Relatively lower chance of complaints as the scale and extent of dredging is

small

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Comparison of Construction Method for

Submarine Outfall (Cont’d)

Dredging Method HDD

Complaints from mariners about large quantity of barges working in

large construction area

Less plant, smaller construction area and shorter duration of construction

Mitigation measures during dredging Nearly no influence on the daily life Mitigation measures during dredgingand backfilling will affect the daily life

of fishermen and mariners

Nearly no influence on the daily life of fishermen and mariners

Operation of Helipad which is in close vicinity to Site will be affected

No influence on the operation of Helipad

Modification of existing seawall structure is required

No modification of existing seawall structure is required.

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Scope of Works (HDD)

Yung Shue Wan Sok Kwu Wan

Diameter of Outfall Pipe 400mm 280mm

Length of Outfall Pipe 550m 730m

Diameter of Drill Hole 600mm 450mm

Max. Depth of Drill Hole -55.5mPD -43.2mPD

Curvature 600m 500m

Geological Condition Marine Deposit

to Grade II Rock

Marine Deposit/ Alluvium

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Principles of HDDLand Side Marine Side

Land Side Marine Side

Pilot Hole

Reaming

Receiving

Pit

Seabed

`

`

Entry Pit

Entry Pit

Land Side Marine SidePipe Pulling

Seabed

Seabed

`

`

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Drill Rods Storage

Water Storage Tank

Site Establishment

Site Boundary

Storage

45t Mobile

Crane Control Cabinet

High Pressure

Mud Pump

Active Tank

Drill Rig

Recycling

Unit

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Drill Rig

High Pressure

Mud Pump

Site Establishment

Entry Pit

Recycling

Unit

Mud Pump

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Pilot Drilling

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Pilot Drilling

250mm Roller Bit

� 6 ¾” Mud Motor

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� Receiving Platform: Steel Frame + Pontoon

Working Platform Steel Frame to support the Temporary Casing

PontoonPlan

View

Reaming

Sea Water Level

Temporary Casing

(700mm Dia.) Alignment of Pilot Drill

PontoonPontoon

Elevation

View

Sea bed Level

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Receiving PlatformTemporary Casing

hung on Platform

Flat Top Barge

Backhoe

Reaming

Flat Top Barge

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Reaming

Support Frame

Temporary Casing hung

on Steel FramePontoon

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Reaming

Reaming

450mm Hole Opener

600mm Hole Opener

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Derrick Lighter

(Assist Pulling)

Pontoon

Receiving Platform

Derrick Lighter (Control

Pipe End Alignment

During Pulling)

Pipe Pulling

Welded Pipe Pulled

toward Receiving Platform

Alignment of

Submarine Outfall

YSW Sewerage

Treatment Work

Drill Rig

Patrol Sampan

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Pipe Pulling

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Pull Head

Pipe Pulling

Pull Head

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Difficulties in Lamma

HDD ProjectHDD Project

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Difficult Ground Profile to Drill Through

� Inferred ground profile by the pilot hole drilling rates at YSW site

Joint number J0-J1 J2-J4 J5-J15 J16-J41 J42-J43 J44-J56

Hole section length 0-24m 24-53m 53-159m 159-411m 411-430m 430-551m

0.7 0.5 3.0 10.1 0.3 1.3 Drilling shift

0.7

shift

0.5

shift

3.0

shift

10.1

shift

0.3

shift

1.3

shift

Average drilling rate34.4

m/shift

58.0

m/shift

35.4

m/shift

25.0

m/shift

64.3

m/shift

92.2

m/shift

Inferred

ground profileSeawall

CDG /

HDGMDG SDG MDG / HDG

CDG, ALL &

MD

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Difficult Ground Profile to Drill Through

� Need to deal with both the softest (Marine Clay) and the hardest (200 MPa Granite) ground which did influence the design and operation considerations.

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HDD Path

Marine Deposit

Grade I / II Granite

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Pulling Stress < 33% of the Pipe Material Tensile Strength

� Pipe buoyancy during pull back operation

� Solution: Fill the pipe with drill mud

Soil / Rock

Product

Pipe

Air Drill Mud

Filter Cake

Cuttings

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Cuttings Cleaned Out from the Product Pipe at

YSW

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Unforeseen Ground Condition

� Design of SKW hole trajectory at tender stage

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Thank You

Q & A

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