Drilling and Design C id iConsiderations

for

Methane DrainageMethane Drainage

Mongolia Coal Mine Methane gProject Development

Workshop

Ulaanbaatar HotelUlaanbaatar, Mongolia

August 30-31, 2010

Presentation OutlineIntroduction

Observations

Methane Drainage Design

Fundamentals of Directional Drilling

- Equipment

- Techniques

Gas Collection

Methane Drainage Techniques

Summary

REI DRILLING, INC.• Operate 8 long hole directional drills and

2 core drills on a contract basis across North America

• Became affiliated with Valley Longwall International in 2008

• Jointly operate >25 long hole drills ld id t t b iworldwide on a contract basis

• Turnkey package of directional drilling units for sale and training for coal miningMethane drainage consulting and• Methane drainage consulting and directional drilling training

• Design and implement methane recovery and sale projectsand sale projects

• Managed and participated in numerous international directional drilling projects

• Expanded uses for directional drilling, p g,e.g. exploration and dewatering

• >25 years experience

International CMM Industryu Coal is the most abundant fossil fuel IEO predicts continuedu Coal is the most abundant fossil fuel. IEO predicts continued

reliance and consumption of coal increasing by 50% by 2030.u Mining technology continues to evolve resulting in more rapid

excavation and production techniques. u We continue to mine deeper, gassier and more challenging coal

reserves. This has resulted in a need to improve methane drainage techniques.U f f d ill d th d i ll h b ff t du Use of surface drilled methane drainage wells has been affected due to surface ownership, approvals, topography, culture, lack of equipment, etc.

u Many coal reserves develop multiple coal seams and require flexibleu Many coal reserves develop multiple coal seams and require flexible methane drainage approach.

u Gas collection systems typically use steel pipeline and demonstrate significant erosion of gas quality from wellhead to surface.significant erosion of gas quality from wellhead to surface.

u There is a recognized need to mitigate methane emissions and demonstrate environmental awareness.

u The international CMM industry shows tremendous growth and y gspread of upstream and downstream technologies.

• Source of gas emissions– Adjacent gas bearing strata, geologic

features or working seam• Geologic characterization• Geologic characterization

– Coal thickness, rank, stress, friability, other mechanical properties

• Reservoir characterizationG– Gas content, permeability, porosity, reservoir pressure, and desorption time constant

• Mining technique and schedule– Gate road development, start of LW,

available drainage times, multiple seams• Drainage approach

– Source, feature, or shield focused, ,• Logistics

– Surface and underground access • Gas Utilization

– Alternatives, gas quality– Market

OPTIMIZE VENTILATION AND METHANE DRAINAGEDRAINAGE

Geologic and Reservoir CharacteristicsGeologic and Reservoir Characteristics

• Gas content of the coal d h l iseam and shale is

commonly determined through the “directthrough the direct method.”

• Core or cuttings are placed in canisters.

• Simulate reservoir conditionsconditions.

• Monitor gas production from core/cuttingsfrom core/cuttings.

Geologic and Reservoir Characteristics• Matrix permeability is the characteristic

that affects the ability of gas (water) to flow through a materialflow through a material.

• Gas flow is also affected by cleat (faceGas flow is also affected by cleat (face and butt) presence, spacing, and jointing.

Borehole Planning and DesignComputer Simulation:Reduction in Residual Gas Content as a Function of Drainage Time and Spacing

of Cross-Panel Boreholes

80%

60%

70%

ent (

%)

40%

50%

idua

l Gas

Con

t

20%

30%

duct

ion

in R

esi

300 ft Spacing

150 ft Spacing

100 ft Spacing

0%

10%

0 1 2 3 4 5 6 7 8 9 10 11 12

Red

0 1 2 3 4 5 6 7 8 9 10 11 12

Months

Why Consider Long Hole Directional Drilling?• Allows longer length and more• Allows longer length and more

accurate placement of boreholes for improved methane drainage efficiency and longer drainageefficiency and longer drainage times

• Allows implementation of i ti b d iinnovative gob gas drainage techniques

• Ability to steer borehole to stay in-seam or hit specific targets

• Promotes a more focused, simplified gas collection systemsimplified gas collection system

• Less labor intensive • Provides additional geologic

i f ti ( h linformation (such as coal thickness, faults, and other anomalies, etc. prior to mining

Long Hole Directional Drills

VLD Series 1000 Track Mounted Directional Drill System

Roof StingerRoof Stinger

Rotation Unit

DGS Uphole Unit Front Chuck

Feed Frame

Track System Stab Jack

VLD SERIES 1000 MODULAR DIRECTIONAL DRILL RIGDIRECTIONAL DRILL RIG

Modular system follows the same design principles as the track mounted system but is broken down into three main componentsmounted system but is broken down into three main components -

power pack, feed frame, and operator’s console - to be used in areas where access is difficult, or there is limited access from the surface.

Operator’s ConsolePower PackFeed Frame

Water Power

100

120

60

80

GP

M

0

20

40

0CDP 70 CDP 100

Down Hole Motors

278/56

312/78

0 50 100 150 200 250 300 350 400Torque

Directional Drilling TechnologyDirectional Drilling Technology• REI uses down hole motor directional drilling technology to

accurately steer long holes in coal seams. A down hole motor, operating on the Moyno pump principle converts hydraulicoperating on the Moyno pump principle, converts hydraulic (water) energy to mechanical torque (bit) without rotation of the drill rods.

• Drillers control direction by orienting a bent housing behind the bit through rotation of the rods The axial force exerted by thebit through rotation of the rods. The axial force exerted by the drill on the rods is distributed to the bit by the bent housing according to its orientation.

Drill BitsPolycrystalline Diamond Cutter (PDC) Impregnated Diamond

Borehole Surveying InstrumentsR l Ti S i DMM MECCA I t tReal Time Surveying – DMM MECCA Instrument

Directional Drilling TechnologyDirectional Drilling Technology• Drillers maintain boreholes in-seam by monitoring down hole

motor pressure, axial thrust, cuttings, and survey information. • Using this system drillers can develop tangential boreholes• Using this system, drillers can develop tangential boreholes

(side-tracks) to help maintain the borehole in-seam, correct trajectory, or develop multiple boreholes from one main branch.

NORTH AMERICAN RECORD• October 6, 2006 • 1623 meters

Drilling ConfigurationDrilling ConfigurationRoof

Reinforced Hose to Pipeline or Diffusion Line

Provisions forGas Measurements

Grout (Cement)Blow Out Preventer

Drill Rod

( )

PVC St l C i

Stuffing Box

Valve

Drill RigOverflow

PVC or Steel Casing

As Necessary

Cuttings / Drilling Water

Floor

Valve and Blow Out ControlValve and Blow Out Control

Gas Handling and CollectionDrilling and Post Drilling

Coal RibLinedwithBothEndsof DilutionZoneHorizontal Borehole

DilutionZone

Canvas Door

Caution

Coal Rib Lined with Canvas or Cement Block

Both Ends of Dilution ZoneCaution Signs with Fencing

Examination PointCH4<1%at Exit

10 ft

X

X

20 to 300 ft

Gas Flow Measurement Provisions

erm

issi

ble

Dril

l Rig

Line CanvasithP t

25 to 50 ft

Canvas Door

Return AirC

autio

n

CH4 <1% at Exit Caution

X

Return Air

Pe

ll

with Posts(as necessary)

Proposed Dilution Zone

Dilution Zone

Per

mis

sibl

e D

rilP

ower

Uni

t

Return Air

Caution Sign

Caution

Dilution Zone is Rock Dustedand kept free of Ignition Sources

Gas CollectionWell head design:

4 inch Casing4 inchBall Valve

4 inch Spring ReturnPneumatic Full Port

Ball Valve

4 inchCheck Valve

4 inch Flex Suction / Discharge Tube

Gauge

4 inchBall Valve

GaugePSI / Inches HG

90 DegElbow

P Gauge

Veribar

4 inch Flex Suction / Discharge Tube

36 inches Schedule 40 (X3)

4 inch TEE

King NippleKing Nipple4 inch

Ball Valve King NippleConnect to Manifold

1/2 inch Pipeline Integrity Line

1/2 inch Pipeline Integrity Line

Sample Port

1/2 inch Pipeline Integrity Line

1/4 inch1/4 inch

8 inch Blind Flange Clean Out

Gas / Water Separator Tank3/16 inch Gage Steel

14 inches X 36 inches

1 inch

4 inch

1 inch Y Strainer

5/8 inch X 3 1/4 inch Bolts / Nuts

King NippleKing Nipple

1 inch Hose (X3)

Pneumatic Valve,Spring OpenPneumatic Valve,

Spring Closed

2 inch1 inch

1 inch Y StrainerSpring Closed

1/2 inch

Float Valve with Sending Unit

Check Valve

Pneumatic Valve,Spring Closed

Water Collection Tank3/16 inch Gage Steel

14 inches X 30 inches

1 inch

1 inch

1/4 inch

Gas Collection

Methane Drainage Techniques• Pre-Mining • Gob Degasification

Longwall Gob Fracture Zone

Coalbed

Coalbed

Coalbed

120 to140 m

Coalbed

Coalbed

Coalbed

SHIELD

50 m10 m 120 to 200 m

20 to 40 m

e / T

an

Elev

atio

n (F

t Bel

ow C

olla

r)

500400200 300100

0

0 600 700 130012001000 1100900800 1400 1500 1600 1700 19001800 2000 2100 2200 2300 2400 2500 2600 2700

-25

-50

531

Ft "G

ood

Gas"

787

Ft "

Goo

d G

as"

925

Ft "

Lots

of G

as"

472

Ft "G

asy"

394

Ft "G

asy"

236

Ft "

Gas

y"

177

Ft "

Gas

y"

138

Ft "

Little

Gas

y"

"Whi

te S

tuff"

872

Ft "

Whi

te St

uff"

1050

Ft "

Rock

"10

52 F

t "Ro

ck"

1086

Ft "

Whi

te S

tuff"

1190

Ft O

ut o

f Roo

f & B

ack

in S

eam

1260

Ft "

Good

Gas"

1378

Ft "

Lots

of G

as"

1555

Ft "

Goo

d Ga

s!!"

2280

Ft F

loor

(Red

dish

)

2346

Ft F

loor

(Red

dish

)

2126

Ft

Roc

k (Ta

n)

2110

Ft R

ock

(Tan

)

2411

Ft R

ock

2461

Ft L

osin

g C

ircul

ation

., Ro

ck

2224

Ft "

Goo

d G

as"

2569

Ft

Rock

Gra

y / R

eddi

sh /

Cho

cola

te / R

ed / T

an /

Whit

eV

ery

Stick

y

Cho

cola

te,

Har

d /

Lt B

rown /

Gray

ishR

ods

Stuc

k

1811

Ft W

arm

Wat

er (5

Gal

/ Min

)

2467

Ft

Hit F

loor

, Red

2493

Ft

Rock

, Flo

or (R

ed)

2638

Ft

Rock

HDH-13 Profile

Vertical Exageration: 4

Ultra Long BoreholesgTo Drain Gas Significantly in Advance of Mining:

Mining

B o re h o le N o . 5

gD

T D = 5 0 4 0 ft

5000

engt

h (f

t)

3000

4000

Bor

ehol

e Le

0 50 100 150 200 250 300Cumulative Recovery (MMCF)

Methane DrainageMethane Drainage• Warrior Basin - Alabama

Methane Drainage Mexico – Case Study

PrePre--Mining Mining -- Long, InLong, In--Seam Directionally Drilled Boreholes:Seam Directionally Drilled Boreholes:

Effect on Gate Road DevelopmentMIMOSA #1 Mine

Methane Emissions, Airflow Requirements, and Advance Rate Before and After Degasification for 2 West Developments, Mine I

8590

Advance Rate (10's of Meters Per Month)

Methane Emissions, Airflow Requirements, and Advance Rate Before and After Degasification for 2 West Developments, Mine I

8590

Advance Rate (10's of Meters Per Month)

70

80 80

70

80

Rat

e

Advance Rate (10 s of Meters Per Month)

Methane Emissions (1000's of Cubic Meters Per Day)

Airflow Rate (Cubic Meters Per Second)

500 m Borehole on Production

70

80 80

70

80

Rat

e

Advance Rate (10 s of Meters Per Month)

Methane Emissions (1000's of Cubic Meters Per Day)

Airflow Rate (Cubic Meters Per Second)

500 m Borehole on Production

45 45 45 45

55

50

60

low

/Adv

ance

45 45 45 45

55

50

60

low

/Adv

ance

20

30

40

Emis

son/

Airf

l

20

30

40

Emis

son/

Airf

l

0

10

0

October November December January February March April May June0

10

0

October November December January February March April May JuneOctober November December January February March April May June

Months in 1994October November December January February March April May June

Months in 1994

Gob Gas Drainage Techniquesg q

Design of Vertical CBM and CMM Wells

Methane DrainageGob Gas – Vertical Gob Wells

High Capacity Horizontal Gob Boreholes

400450

FD)

50100150200250300350

Gob

Gas

Flo

w (M

CF

050G

Cambria 33 Tiefa Saarland WillowCreek

Ukraine - Methane Drainage Approach Degassing Boreholes Drilling Diagram

Degassing BoreholesReturn Entry

Drill Rig

9th South Panel

Conveyor Entry

Legend

Intake AirReturn Air

Ventilation Door

Crossing

Hau

lage

Way

Water Sump

Sou

ther

n Sl

ope,

2nd

Sta

ge

Man

way

219

0

? - ?

453 0453 0

314

031

40

314

031

40

45 3045 30 45 3045 30

314

031

40

Upper Coal SeamDegassing Boreholes

9th South Longwall

Upper Coal SeamHaulage Way

Drill Rig

Manway

Southern Slope2nd Stage

Horizontal Gob Borehole Design Considerations • Near edges of the longwall panel where strata will be in tension.• Parallel and along ventilation return (tailgate).• On high elevation side of the gob.

( )• Above rubble zone (> 5 times mining height) to remain intact during undermining.

• Typical placement is 20 to 30 m above top of coal.

D e g a s s i n g B o r e h o l e s D r i l l i n g D i a g r a m

D e g a s s i n g B o r e h o l e sR e t u r n E n t r y

D r i l l R i g

9 t h S o u t h P a n e l

L e g e n d

I n t a k e A i rR e t u r n A i r

Hau

lage

Way

W a t e r S u m p

outh

ern

Slo

pe, 2

nd S

tage

Man

way

2190

? - ?

4 5 3 04 5 3 0

31

403

140

31

403

140

4 5 3 04 5 3 0 4 5 3 04 5 3 0

31

403

140

C o n v e y o r E n t r y

V e n t i l a t i o n D o o r

C r o s s i n g

H

U p p e r C o a l S e a mD e g a s s i n g B o r e h o l e s

U p p e r C o a l S e a mH a u l a g e W a y

D r i l l R i g

M a n w a y

S o u t h e r n S l o p e2 n d S t a g e

So

9 t h S o u t h L o n g w a l l

Krasnolimanskaya Mine

Case StudyR d ti f th Li h MiRecommendations for the Liuzhuang Mine

Liuzhuang is located in East China Coal Region. Faulting and fragile coals with low permeability makes in-seam drilling less effective.

• Top: Retreat longwall mine employing 220-280 m x 1500-1700

Liuzhuang : Pre-Drainage In-Seam Boreholes Current vs Recommended

meter panels

• Currently, cross-panel in-seam boreholes are drilled from the tailgate 80-110 m long on 6-m spacing .

• Boreholes probably stay in the lower half of the 4.5-m thick seam 13-1.

CURRENTPROCEDURE

6-m spacing

• Bottom: Recommended changes to in-seam borehole drilling strategy

• Directional drilling equipment

• 19-m borehole spacing

• 225-m long in-seam boreholes gshould be feasible.

• Top and bottom of seam drained

• Similar residual gas content RECOMMENDED

FUTURE PLAN

reduction with > CH4quantity/concentration..

19-m spacing

Gob Drainage: CURRENT• Top: Cross-measure boreholes are

drilled toward the retreating longwall face.

• Drill stations are spaced ~80 m alongDrill stations are spaced 80 m along tailgate entry, ramped up 10 m into overlying strata.

• Boreholes up to 110 m long and 50-90 mm diameter are angled up 15

CROSS-MEASURE BOREHOLES DRILLED FROM STATIONS ALONG

90 mm diameter are angled up 15-30° into the overlying rock strata.

• Stations are sealed and connected to vacuum.

DRILLED FROM STATIONS ALONG THE TAILGATE ENTRY • CMM is produced as panel is mined

through and gob created. It later is isolated to limit ventilation air contamination.

• Bottom: Drilling gallery is developed in rock about 18-25 m above seam.

• Gallery is located along tailgate side of panel.

• Gallery is sealed to limit air influx.

SUPERJACENT GALLERY DRIVEN ABOVE THE MINING SEAM

• Gallery is connected to vacuum system.

1500-1700m

30°

Gob Drainage : RECOMMENDED

10m

20m

20m

50m

220-280mIN- MINE GOB BOREHOLES DRILLED FROM STATIONS ALONG

• Current design could be replaced by long, 1000-m horizontal gob boreholes directionallyDRILLED FROM STATIONS ALONG

THE TAILGATE ENTRY1000 m horizontal gob boreholes directionally drilled from the ends of the panel.

• Could accomplish similar results.

PLAN VIEW

5m

SEAM 13-1

750-1000m

4m

30m

10mCROSS SECTION VIEW

750 1000m

• 75% fewer boreholes drilled (counting the tangential boreholes

Benefits of Recommended Cross-Seam and Gob Borehole Improvements

( g gindividually)

• 88% fewer drill setups, borehole collars, standpipes, and wellheads

• Same volume of methane recovered• Same volume of methane recovered

• Fewer wellheads minimizes potential for air intrusion into gathering system, thus improving recovered gas quality

• Fewer boreholes reduces methane drainage costs

• Potential for reduction in drainage time by reducing borehole spacing

• Fewer boreholes provides for reduced time required for drilling• Fewer boreholes provides for reduced time required for drilling

• Reduced residual gas contents improves mine safety

• Reduced residual gas contents enables increased coal production

Average Recovered Gas Quality (% CH4)

Current 5 -15

Recommended 40 - 70

Summary • Acquisition of geologic and reservoir• Acquisition of geologic and reservoir

properties allows mine operator to optimize methane drainage technique rather than use “trial and error.”

• Evaluate alternatives from drill bit to burner tip (e.g. drainage techniques, equipment, well heads, pipeline, safety q p , , p p , ysystems, surface facilities, and gas use options).

• Directional drilling will allow application g ppof modern methane drainage techniques tailored to site specific conditions.

• Provides geologic information such as coal thickness/thinning, identification of faults, intrusions, other anomalies, old workings, etc., prior to mining.