UNFC-2009 and Unconventional Resources · 2011. 2. 15. · PRMS and Unconventional resources •...

UNFC-2009 and Unconventional ResourcesA review of problems in reporting Unconventional Energy Resources and potential applications of UNFC-2009

Jan RoelofsenSr. Product Manager Unconventional EnergyIHS Global SA Geneva

Copyright © 2011 IHS Inc. All Rights Reserved.

What is unconventional?• Better definitions:

• continuous-type hydrocarbon deposits• gas / oil resource plays

• Should we also include:• Oil sand / bitumen: a deposit that can be mined and from which oil can be

extracted as a chemical process

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Copyright © 2011 IHS Inc. All Rights Reserved. 3

Unconventional-Conventional: the difference• Both produce gas, but they should be considered as two different

resources Conventional accumulation• trap defined by oil / gas water contact• volume to be determined by modern technology (seismic, reservoir models)• porous reservoir• movable hydrocarbons

GIP = volume * Ø * (1-Sw) * FVF

Unconventional resources• no clear extent, continuous• no clear volume to be determined• technology limitations (so far)• micro-pores, limited connectivity• hydrocarbons adsorbed to shale, coal

determinedby “sweet spot” measured

calculatedvariable

GIP = area * pay thickness * gas content

estimatedvariable


Determining unconventional plays• Determine prospective area / pay based on:

• extent of shale, coal layers• richness in kerogen• maturity (transformation of kerogen in oil/gas)• depth (adequate for production)• rock properties (fracturing)

• Gas Content:• direct core measurements (Langmuir constants)• but what is variation over distance?• calculated using kerogen transformation - reliable?

• How to quantify uncertainty?

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Sweet spot definition• Understanding play characteristics takes time and much drilling• Steep learning curve has effect on initial project economics

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0200400600800

1,0001,2001,4001,6001,8002,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Gas

Pro

duct

ion

(MM

scfd

)

Quarters from first well in play

HaynesvilleFayettevilleMarcellusEaglefordWoodford


Recovery factor• Only a very small part will be produced• Example from Cambrian shale in North Europe• How can we determine recovery at an early project stage?

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Net recoverable

63 Tcf(20%)

GIP 315 Tcf Risked

recoverable6 Tcf(1.9%


Different exploration & development concepts• different time-scales require different legislative concepts

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SeismicExpl. drilling

(1 well)

Appraisal(1-2 wells) Development Production

SeismicExploration drilling

“sweet spot” location(10-15 wells)

Appraisal“sweet spot” testing

(production)Dev Production

Geological knowledge

Project feasibility

Economic viability

Low Moderate High

Low

Low

Moderate

Moderate

High

High


Project feasibility

Economic viability

Low Moderate High

Low

Low

Moderate

Moderate

High

High

Exploration licensetypically 3-5 years Production license


Resources definition• Geological knowledge:

• reaches high confidence level not before production is established• “proven” reserves only for producing part• difficult to extrapolate play characteristics over long distances

• Project feasibility: • steep learning curve, different for each play• many wells required to establish sweet spot and production profile

• Economic viability:• legislation not adapted, uncertainty about exploration license duration• production uncertainties

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PRMS and Unconventional resources• SPE paper by Barker (2008) describes problems in definition of Proven,

Probable and Possible• Conventional: reserves based on uncertainty in recovery• Unconventional: reserves based on maturity of development

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G.J. Barker (2008), Application of the PRMS to Coal Seam Gas, SPE 117124

1P

2P

3P

Res

erve

s

Time and maturity of project

1P

2P

3P

Res

erve

s

Time and maturity of project

Conventional projects Unconventional projects


CBM testing / production• CBM pilot projects: long dewatering phase and

unknown desorption behaviour

10

0

100

200

300

400

500

600

700

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Gas contentscf/ton

Pressure (psi)

Pseudo‐isotherm curve for coalIsotherm

Langmuir at PL

Storage Capacilty

Gas content

Initial pressure

Critical desorption pressure

Abandonment press.

Production start at critical desorption pressure

Dewatering phase

Pilot project to test desorption behaviour


PRMS and Unconventionals• CBM pilot projects or sweet-spot drilling of shale gas projects:

where does it fit?

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Pilot?

Pilot?

Pilot?


Defining proven reserves• Drainage area around producing well with proven and probable areas

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One block is a “section”640 acres = 2.91 km2

Proven area

Probable area area

Possible area


Current block-bounded approach• producing area bounded by sections (640 acres)

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Case 1:proven: 6 sections = 3,840 acres = 16 km2

probable: 80 sections = 51,200 acres = 208 km2

Case 2:proven: 28 sections = 17,920 acres = 73 km2

probable: 58 sections = 37,120 acres = 150 km2

1P or 2P ?1P


Circular drainage areas?

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Proven area

Probable area


Horizontal wells• Drainage area not rectangular or circular

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Proven area

Probable area area


More realistic approach• Based on geological evidence, UNFC gives more detail

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proven: 39,680 acres = 161 km2

probable: 32,000 acres = 129 km2

long-term pilot test112 or 222?

producing from few wells111 or 112?

CBM well drilledbut not yet tested222 or 223?

334

344

333

Class acres sq km112 16,000 65222 10,880 44223 12800 52333 23,040 93334 8,960 36


UNFC-2009 for CBM

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F4

E1

E2

E3

F1

F3

F2

G2G1

G3G4


Project feasibility

Socio

-eco

nom

ic via

bilit

y

CBM producing or tested

CBM prospective area

CBM possible area


Example• classification based on degree of pilot tests and geological knowledge

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111

222

223

233

343223

344


UNFC-2009 for shale gas resources

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The END

20

F4

E1

E2

E3

F1

F3

F2

G2G1

G3G4

UNFC-2009 and Unconventional Resources · 2011. 2. 15. · PRMS and Unconventional resources •...

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