[PPT] - Numerical Modeling of ExxonMobil s Electrofrac TM Field Experiment PowerPoint Presentation

SLIDE 1

Numerical Modeling of ExxonMobil’s ElectrofracTM Field Experiment at Colony Mine

Nazish Hoda, Chen Fang, Michael W. Lin, William A. Symington, and Matthew T. Stone

ExxonMobil Upstream Research 30th Oil Shale Symposium October 19, 2010

SLIDE 2

2

Ele Electr trofr

frac Pr

Proc

cess Sc

ss Sche hematic tic

Oil Sha Oil Shale le C Con

nversion via

sion via Ele Electric trically C lly Conduc

nductiv

tive F Fractur tures s

Oil shale is heated in situ by a hydraulic

fracture filled with an electrically conductive material1

Electricity is conducted from one end of

the fracture to the other, making it a resistive heating element

Heat is conducted into the formation,

converting the kerogen into oil and gas

Oil and gas are produced by conventional

methods

Potential for cost-effective recovery with

less surface disturbance than:

Mining and retorting
Competitive in situ processes
Several years of research are required to

demonstrate technical, environmental, and economic feasibility

1 U.S. patent 7,331,385 B2

Ele Electr trofr

fracTM

TM Pr

Proc

cess

ss

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3

Parachute hute Battle ttlement Me nt Mesa sa

I-7 I-70

Mine Mine Benc nch h Tunne unnels ls

Loc Location of tion of Exx ExxonMobil

nMobil’s C

s Colony Mine

lony Mine

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4

C

k

e

f

i l l e d E l e c t r

f

r a c M i n e R i b Insulated Coating on Steel Pipes Connection Treatments

E l e c t r i c c u r r e n t

C

k

e

f

i l l e d E l e c t r

f

r a c M i n e R i b Insulated Coating on Steel Pipes Connection Treatments

E l e c t r i c c u r r e n t

Pumped two Electrofracs with

calcined coke. Mapped and verified with observation coring.

Pumped/squeezed Electrofrac

power connections at EF1 and

EF3. Preceded by lab and field

pretests.

Instrumented and heated

Electrofracs in low-temperature tests

EF3

EF3 in 2 in 2009

EF1

EF1 in 2 in 2010. .

Built and verified two Electrofracs: EF1 ~140 ft EF3 ~200 ft Cored 28 observation holes: All intersections probed are electrically connected

EF1 EF3

Instrumentation Holes on EF1

99 ft 132 ft N

r

t h D r i f t S

u

t h D r i f t Crosscut Decline

Built and verified two Electrofracs: EF1 ~140 ft EF3 ~200 ft Cored 28 observation holes: All intersections probed are electrically connected

EF1 EF3

Instrumentation Holes on EF1

99 ft 132 ft N

r

t h D r i f t S

u

t h D r i f t Crosscut Decline

Building a uilding and Ope nd Operating ting Ele Electr trofr

fracs

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5

16 T The herm rmoc

couple
uple H

Hole

les

s 16 F Fibe iber Optic r Optics H s Hole

les

s Crossc

sscut

ut 11 T The herm rmoc

couple
uple /

/ Fibe iber H r Hole

les

s Captur ptures T s Tempe peratur ture, V , Volta

ltage, C

, Cur urrent a nt and R nd Roc

ck Mo

Movement D nt Data ta Nor

rth

th

EF1 EF1 EF3 EF3 EF1 EF1 & & EF3 EF3 Instr Instrum umenta ntation tion

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6

Ex Excelle llent Oppor nt Opportunity to C tunity to Calibr librate te N Num umeric rical Mode l Models ls

Ø Ele Electric trical Mode l Modeling ling:

calibrate model to match electrical measurements
derive distribution of graphite connections on the

fracture

predict heat input distribution on the fracture

Ø T The herm rmal Mode l Modeling ling:

calibrate model to match measured temperatures
derive heat input distribution
estimate thermal diffusivity of surrounding rocks

Muc Much D h Data ta C Colle

llecte

ted D d During EF3 uring EF3 Expe Experim riment nt

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7

Develop a model to match electrical measurements, and use it to

predict heat input distribution on the fracture

Distribution (thickness) of calcined coke in the fracture from core
1.000
0.796

Cok

ke f

fille illed fr d fractur ture

Me Measur sured V d Volta

ltages

s

0.8 .8 0.7 .7 0.0 .0 OB OB2 OB OB4 OB OB3 OB OB16 OB OB9 0.9 .9

0.4

.4

0.8

.8 1.0 .000 0.9 .902 0.6 .679

0.0

.033 0.0 .054

1
1.0

.000

0.7

.773 0.9 .904 0.0 .027 OB OB5 OB OB14 OB OB17 OB OB15 0.6 .677 EF3 EF3 OB OB13 0.3 .330

Ele Electric trical Mode l Model: EF3 l: EF3 Expe Experim riment nt

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8

Spatial distribution of graphite thickness tuned to

match observed voltages

Mode Modele led V d Volta

ltage D

Distrib istribution ution

1
1.0

.000 1.0 .000

0.7

.796

0.0

.041

0.0

.0432

0.0

.038

0.7

.742 0.2 .282 0.7 .729 0.9 .923 0.8 .895

Me Measur sured V d Volta

ltages

s

0.8 .8 0.7 .7 0.0 .0 OB OB2 OB OB4 OB OB3 OB OB16 OB OB9 0.9 .9

0.4

.4

0.8

.8 1.0 .000 0.9 .902 0.6 .679

0.0

.033 0.0 .054

1
1.0

.000

0.7

.773 0.9 .904 0.0 .027 OB OB5 OB OB14 OB OB17 OB OB15 0.6 .677 EF3 EF3 OB OB13 0.3 .330

Excellent agreement between modeled and measured voltages

OB4 OB9

Ele Electric trical Mode l Model: EF3 l: EF3 Expe Experim riment nt

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9

Mode Modele led H d Heat Input D t Input Distrib istribution ution

ü Ele Electric trical Mode l Modeling c ling can be n be use used to pr d to predic dict he t heat input distrib t input distribution ution fr from

m obse
bserved v

d volta

ltage distrib

distribution on the ution on the fr fractur ture

A F Forw

rward Mode

d Model to Pr l to Predic dict H t Heat Input D t Input Distrib istribution ution

Heat input distribution predicted from distribution of

conductive material and voltage

Predictions for different time slices suggest little temporal

variation in heat input distribution

Btu/ft2-hr

OB4 OB9

30 20 10

Ele Electric trical Mode l Model: EF3 l: EF3 Expe Experim riment nt

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10

Develop a thermal model to match measured temperatures

at different times in the 90-day experiment

Estimate thermal diffusivity of surrounding rocks and derive

heat input distribution

An In n Inverse se Mode Model to Pr l to Predic dict H t Heat Input D t Input Distrib istribution ution

1.000

Fibe iber Optic r Optics H s Hole

les

s The herm rmoc

couple
uple H

Hole

les

s

The herm rmal Mode l Model: EF3 l: EF3 Expe Experim riment nt

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11

Good agreement between modeled and measured temperatures

Parallel Perpendicular Deriv rived H d Heat Input D t Input Distrib istribution ution

OB4 OB9

Btu/ft2-hr

OB4 OB9

The herm rmal Mode l Model: EF3 l: EF3 Expe Experim riment nt

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12

Predicted temperature after 90 days

º F

Sensitivity analysis performed to estimate thermal diffusivity
1-D model developed to estimate thermal diffusivity from

temperature fall-off data

Estimated thermal diffusivity range, 0.45 - 0.6 ft2/day, agrees

with lab and field measurements

The herm rmal Mode l Model: EF3 l: EF3 Expe Experim riment nt

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13

Heat input distributions predicted by electrical and thermal models have same general attributes Predicted Heat Input Distributions

Electrical Model Thermal Model Btu/ft2-hr 30 20 10 32 24 16 8

OB4 OB9 OB4 OB9

Calibr librate ted Mode d Models: EF3 ls: EF3 Expe Experim riment nt

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Calibr librate ted Mode d Models: EF3 ls: EF3 Expe Experim riment nt

Ø Field experiment verified that electrically conductive fracture can be constructed in the field and operated at low temperatures Ø Numerical models developed to analyze thermal and electrical data collected during the experiment Ø Electrical model calibrated to match voltage measurement and to predict the heat input distribution on the fracture Ø Thermal model calibrated to match measured temperatures and to derive heat input distribution Ø Heat input distributions predicted by the two models have same general attributes

Conc

nclusions:

lusions:

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15

Calibr librate ted Mode d Models: EF1 ls: EF1 Expe Experim riment nt

Me Measur sured V d Volta

ltages

s Thermal modeling

20 F Feet t

1.0 .00 0.9 .99 0.7 .78 0.2 .28 0.8 .81 0.6 .63 0.3 .34 0.2 .25 0.3 .33

0.6

.64

0.5

.50

0.9

.94

0.9

.90

1
1.0

.00

0.9

.90

Ong Ongoing W

ing Wor
rk:

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