Enhanced Coalbed Methane Recovery and CO2 Storage in Coal … · 2017-10-31 · 1 Enhanced Coalbed Methane Recovery and CO 2 Storage in Coal Seams Sevket Durucan Department of Earth
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1
Enhanced Coalbed Methane Recovery and CO2 Storage in Coal Seams
Sevket Durucan Department of Earth Science and Engineering
Imperial College London
APEC Seminar, AIST, Tsukuba, 7 December 2007mINING AND ENVIRONMENTAL ENGINEERING RESEARCH GROUP
Background
Coalbeds as both the reservoir and source rock
OUTLINE
Retention and release of gas in coal
Coal permeability, dynamic permeability modelling in coalbedreservoir simulation
Reservoir simulation of enhanced Coalbed Methane recovery and CO storage in coal seams
APEC Seminar, AIST, Tsukuba, 7 December 2007
CO2 storage in coal seams
Conclusions
2
World Carbon Dioxide Storage Options
Deep Ocean
Saline Aquifers
Unminable Coal Seams >15 Gt CO
Depleted Oil Reservoirs
Depleted Gas Reservoirs
Unminable Coal Seams >15 Gt CO2
APEC Seminar, AIST, Tsukuba, 7 December 2007Source: USGS
Major Coal Basins
APEC Seminar, AIST, Tsukuba, 7 December 2007
3
Major Coal Basins
APEC Seminar, AIST, Tsukuba, 7 December 2007
Major Coal Basins and Methane ResourcesContinent Country Coal Resources Methane Resources
x 109 tonnes x 1012 m3
Europe and Belgium 0.075the Russian France 0.600Federation Germany 320 2.85Federation Germany 320 2.85
Hungary 0.085Poland 160 2.85Russia 6,500 17-113Ukraine 140 1.7UK 190 1.7
North America Canada 7,000 5.7-76USA 3,970 11
Asia China 4,000 30-35India 160 0.85
APEC Seminar, AIST, Tsukuba, 7 December 2007
Indonesia 6Kazakhstan 170 1.13
Australia 1,170 8.5-14
Africa 150 0.85
World Totals ~25,000 ~84 - 262Source: ARI, 1992
4
Underground Methane Drainage Practice
Coalbed Methane Technology
Methane Extraction from Coal Seams: Well Technology
APEC Seminar, AIST, Tsukuba, 7 December 2007
Coal as a Reservoir Rock: Structure
Uniform and orthogonal fracture (CLEAT) structure
APEC Seminar, AIST, Tsukuba, 7 December 2007
microcleat
5
Coal as a Reservoir Rock: Structure
f l t
butt cleat
adsorbed gas
Coal Matrixcontaining
pores
face cleat
Macropores > 50 nm
M 2 50
microcleat
APEC Seminar, AIST, Tsukuba, 7 December 2007
free gas
CH4
Mesopores 2 – 50 nm
Micropores < 2 nm
Cleat system (2mm - 25 mm)
Pore surface area 20 – 200 m2
Coal as a Reservoir Rock – Gas Retention
butt cleat
adsorbed gas
Coal Matrixcontainingmicropores
face cleat
8
12
16
20
s C
onte
nt, m
3 /t
CH4 adsorption isotherm
APEC Seminar, AIST, Tsukuba, 7 December 2007
free gas
CH4 0
4
0 1 2 3 4 5 6 7 8Pressure, MPa
Gas
6
Coal as a Reservoir Rock: CH4 / CO2 Retention in Coal - Adsorption Isotherm
COt)
1,000
Pressure (MPa)0 1.4 2.8 4.2 5.6 7
CO2
75%CO2 25%CH4
CH4
Gas
con
tent
(m3 /t
10
15
5
0
800
600
400
Gas
Con
tent
(sc
ft/t
onne
)
APEC Seminar, AIST, Tsukuba, 7 December 2007
Pressure (MPa)
0 200 400 600 800 1,000 1, 200Pressure (psi)
0
200
pPpVV+
=L
LLangmuir equation:
Enhanced Coalbed Methane Recovery (ECBM)two principal methods of ECBM, namely N2 and CO2 injection (inert gas stripping and displacement sorption respectively)
injection of nitrogen reduces the partial pressure of methane in the reservoir, th t th d ti ith t l i th t t l ithus promotes methane desorption without lowering the total reservoir pressure
20
25
m3 /t
)
CH4 7% moist. coal CO2
3 /t)
15
coal can adsorb approximately two to six times as much CO2 by volume as methane, therefore, the assumption has been that the CO2 injection stores 2-6 moles of CO2 for every mole of CH4 desorbed.
APEC Seminar, AIST, Tsukuba, 7 December 2007
Pressure (MPa)0 4 8 122 6 10 16
10
5
15
20
014
Gas
con
tent
(m
N2 7% moist. coal
Pressure (MPa)0 1.4 2.8 4.2 5.6 7
75%CO2 25%CH4
CH4
Gas
con
tent
(m3
10
15
5
0
7
CoalSite
Durango
Tiffany Unit
Florida River Plant
McElmoD
Simon Pilot
San Juan BasinSimon Pilot
Colorado
NewMexico
Sweet
COLORADONEW MEXICO
SpotFarmington
Overpressured:Sw = 1.0
Allison Unit
Tiffany UnitDomeCO2 Field
APEC Seminar, AIST, Tsukuba, 7 December 2007
Underpressured:Sw < 1.0
Underpressured:Sw = 1.0
Scale, miles0 10 20
Amoco Simon N2 Injection Pilot
Simon Pilot
Nitrogen
1,600
1,200
800
Start NitrogenInjection
Total Gas
End NitrogenInjection
Rat
e M
scf/
D o
r ST
B/D
APEC Seminar, AIST, Tsukuba, 7 December 2007
Natural Gas
1988 1989 1990 1991 1992 1993 1994 1995
400
0Water
NaturalGas
Gas
/Wat
er R
Source: Wong, Gunter, Law and Mavor, 2000
8
CoalSite
Durango
Tiffany Unit
Florida River Plant
McElmoD
Simon Pilot
San Juan BasinTiffany Unit
Colorado
NewMexico
Sweet
COLORADONEW MEXICO
SpotFarmington
Overpressured:Sw = 1.0
Allison Unit
Tiffany UnitDomeCO2 Field
APEC Seminar, AIST, Tsukuba, 7 December 2007
Underpressured:Sw < 1.0
Underpressured:Sw = 1.0
Scale, miles0 10 20
BP Tiffany Unit N2 Injection (Full Scale Commercial Pilot)
12 N2 injector wells,
34 CH production wells
9 Years of primary production,
Tiffany Unit
34 CH4 production wells,
N2 injection started in January 1998,
4-6 fold increase in production
early N2 breakthrough
Source: Reeves and Peckot, ARI, USCBM Symp, 2001
Nitrogen Injection Suspended100000
APEC Seminar, AIST, Tsukuba, 7 December 2007
Nitrogen Injection Suspended
Water Measurement Discrepency
Water ProductionGas Production
Nitrogen Injection
100
10
1000
10000
1May-90 Sep-91 Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02
Rat
e, M
cfd
or B
pd
9
BP Tiffany Unit N2 Injection (Full Scale Commercial Pilot)
Nitrogen Injection Suspended
Water ProductionGas Production
100000
Tiffany Unit
Water ProductionNitrogen Injection
100
1000
10000
Rat
e, M
cfd
or B
pd
APEC Seminar, AIST, Tsukuba, 7 December 2007
Source: Reeves and Pecot, ARI, USCBM Symp, 2001
Water Measurement Discrepency
10
1May-90 Sep-91 Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02
CoalSite
Durango
Tiffany Unit
Florida River Plant
McElmoD
Simon Pilot
San Juan BasinAllison Unit
Colorado
NewMexico
Overpressured:Sw = 1.0Sweet
COLORADONEW MEXICO
SpotFarmington
Allison Unit
Tiffany UnitDomeCO2 Field
APEC Seminar, AIST, Tsukuba, 7 December 2007
Scale, miles0 10 20
Underpressured:Sw < 1.0
Underpressured:Sw = 1.0
10
Burlington Resources Allison Unit CO2 Injection
4 CO2 injector wells,
9 CH4 production wells,
6 Years of primary production (1988/89 – 1995),
Allison Unit
McElmoDomeCO2 Field
9 CH4 production wells,
CO2 injection started in May 1995,
reduced CO2 injectivity with time
No significant CO2 breakthroughSource: Reeves and Pecot, ARI, USCBM Symp, 2001
Alb t R h C il F Bi V ll CO I j ti
APEC Seminar, AIST, Tsukuba, 7 December 2007
Alberta Research Council, Fenn Big Valley CO2 Injection
coal swelling and reduced permeability observed
Field micro-pilot testing started in 1997
Source: Wong and Gunther, 1999Law, Van der Meer, Mavor and Gunter 2000
Burlington Resources Allison Unit CO2 Injection
Allison Unit
McElmoDomeCO2 Field
APEC Seminar, AIST, Tsukuba, 7 December 2007Source: Reeves, ARI, Coal-Seq Forum, 2002
11
Coal Permeability and Gas Flow
“… contrary to what is usually supposed, solid coal is extremely airtight, and lets very little air or gas through, even with a driving pressure of a whole atmosphere.”
Ivor GRAHAM, 1916
“….that the rate of gas flow through the coal is a function of thedifference in partial pressure of methane along the flow path. Therefore, the emission of methane from a lump of coal is not
APEC Seminar, AIST, Tsukuba, 7 December 2007
, pdependent on the total external pressure, but upon the partial pressure of the methane in the atmosphere and the pressure of the gas in coal.”
Ivor GRAHAM, 1919
Strength, Elastic and Flow Properties of Coal
Coal structure is highly elastic
LimestoneSandstoneWeak
Reservoir S d t
Coal(Various) Shale
fractures matrix
0.86 - 3.9 35 - 5510- 200.4 – 1.8
Young’s Modulus, E
(GPa)
Sandstone( )
5 - 70
10
15
20
25
Stre
ss (M
Pa)
APEC Seminar, AIST, Tsukuba, 7 December 2007
Coal permeability is• Anisotropic
• Highly stress dependent
0
5
10
0 10 20 30 40 50 60Axial Strain (millistrain)
Axia
l S
CAYDAMARBARNSLEYCOCSHEADBANBURYDUNSILDEEP HARD
12
Stress Effects and Permeability
0.5
0.6
md) Durucan Puri et al Somerton
10-1
5 m
2
3001000
Three Yard
APEC Seminar, AIST, Tsukuba, 7 December 2007
1000 1200 1400 1600 1800 2000 2200 24000
0.1
0.2
0.3
0.4
Effective Stress (psi)
Perm
eabi
lity
(m
•Intact coal
10
Perm
eabi
lity
(k),
1
Confining Stress (MPa)0 2 4 6 8
0.313
1030
100300
Great RowCannel Row
•Fractured coal
Field Experience: San Juan Basin Field Permeability Behaviour
Pressure dependent permeability multiplier
2345678
k / k
(p =
800
psi
)
APEC Seminar, AIST, Tsukuba, 7 December 2007
(after McGovern, 2004)
012
0 100 200 300 400 500 600 700 800 900Reservoir pressure (psia)
13
Pore Pressure Effects on Permeability: Matrix Shrinkage and Swelling
Lorraine
4000
6000
8000
tric
stra
in
ostra
in)
CO2
CH
fractures matrix
1
-2000
0
2000
0 1 2 3 4 5 6 7 8Cell pressure (MPa)
Vol
umet
(mic
ro CH4
He
pP
pV+
=
L
Lεsαs
APEC Seminar, AIST, Tsukuba, 7 December 2007
0.001
0.01
0.1
0 1 2 3 4Pore pressure (MPa)
Per
mea
bilit
y (m
D)
CO2 permeability (Lorraine)
CH4 permeability (Lorraine)
CO2 permeability (Schwalbach)
Primary and Enhanced Coalbed Methane Recovery Permeability Model
APEC Seminar, AIST, Tsukuba, 7 December 2007
14
Model for Changes in Coalbed Permeability During Primary Recovery
)(3 0f σ−σ−= cekkFlow
Bundled matchstick model
bk3
121=)(
00f= ekk
b
a
σ – σ0 - changes in effective horizontal stress (after Seidle et al., 1992)
cf – cleat volume compressibility
a12
APEC Seminar, AIST, Tsukuba, 7 December 2007
)1(3)()(
10
00 ν−−α
+−ν−
ν−=σ−σ
VVEpp S
E – Young’s modulus
ν – Poisson’s ratio
αS – shrinkage coefficient
V – adsorbed gas volume
shrinkage termcompaction term
Schematic Permeability Behaviour
rbpp >0σ−σ0
A
150
200
250
300
ent (
SC
F/to
n)
)(1)1(3
)(0
00 ppVVE S −
ν−ν
−ν−−α
=σ−σ
rbpp <0
σ−σ0 BA
B
VL = 448 SCF/ton1/b = 525 psi
p0prc0
prb
p
APEC Seminar, AIST, Tsukuba, 7 December 2007
0
50
100
0 300 600 900 1200 1500 1800Sorption pressure (psia)
Gas
con
te
p0 prc0
prb
p
pprb
15
Model Validation: US San Juan Basin History MatchValencia Canyon Wells: Steady increase in permeability
20
25well test
1 5
2history matched permeability
Fairway B1 “boomer” Well: Strong permeability rebound
2p0 = 1500 psi
0
5
10
15
0.2 0.4 0.6 0.8 1p/p0
k/k 0
VC 32-4
VC 29-4VC 32-1
VC 32-1 (Mavor and Vaughn)
20
25well test
0
0.5
1
1.5
500 700 900 1100 1300 1500
Reservoir pressure (psi)
k/k0
response curve at fairway B1(Palmer and Mansoori)
APEC Seminar, AIST, Tsukuba, 7 December 2007
0
0.5
1
1.5
500 700 900 1100 1300 1500
Reservoir pressure (psi)
k/k0
Present model
P & M model
p0 = 1500 psi
φ0 = 0.00085 METSIM
0
5
10
15
20
0.2 0.4 0.6 0.8 1.0p/p0
k/k 0
VC 32-1
present studyMavor and Vaughn
VC 32-4
VC 29-4
METSIM
Permeability Model For Enhanced Recovery
)(30
0f σ−σ−= cekk Cleat permeability
)1(3)()(
10
00 ν−−α
+−ν−
ν−=σ−σ
VVEpp S
Primary recovery
Enhanced recovery
Shrinkage/swelling term
APEC Seminar, AIST, Tsukuba, 7 December 2007
aSj – shrinkage/swelling coefficient for gas component j
)()1(3
)(1 0
100 j
n
jjSj VVEpp −α
ν−+−
ν−ν
−=σ−σ ∑=
16
Imperial College in-house ECBM Simulator METSIM2
• 3D two-phase Darcy flow in cleats, Fickian diffusion in matrix (allows for bidisperse diffusion)
• multi-component gas mixture (CH2, CO2, N2)
• matrix shrinkage/swelling effects one permeability
• mixed gas sorption and diffusion
APEC Seminar, AIST, Tsukuba, 7 December 2007
• extended Langmuir model
Yubari Field Pilot, Hokkaido, Japan
(after Fujioka, 2006)
APEC Seminar, AIST, Tsukuba, 7 December 2007
• In a mountainous national forest area
• Bounded by four major faults
17
Yubari Field Test
Three stages
• CO2 injection huff-puff test (well 1 CO )IW-1, 7.5 tons CO2)
• Multi-well CO2 injection tests• 2004 (16 days, 35.7 tons CO2)• 2005 (42 days, 115.4 tons
CO2)
• N2 flooding test• 2006 N flooding (9 days 32
APEC Seminar, AIST, Tsukuba, 7 December 2007
• 2006 N2-flooding (9 days, 32 tons N2)
• 2006 Pre- and Post-N2flooding CO2 injection • Well tests prior to the test and
after 2004 CO2 injection• 1 -> 0.08 md
Multi-well test: Production and injection rates
300
400
m3 /d
)
1600
2000
3 /d)
CO2 injection rate
CO2 Injection and N2 Flooding TestField Injection and Gas Production Rates
2004:
0
100
200
300
20-Aug 1-Sep 13-Sep 25-Sep 7-Oct 19-Oct 31-Oct
2005
Gas
pro
duct
ion
rate
(m
0
400
800
1200
CO
2 inj
ectio
n ra
te (m
3
production rate
CO2 & N2 injected and gas & water production rates 7 800
CO2 (ton) N2 (ton)
2005
2004:• 15 days injection• 1.8 – 2.9 tones CO2/day
(1 ton = 506 std. m3)
2005:• 40 days injection
APEC Seminar, AIST, Tsukuba, 7 December 2007
0
1
2
3
4
5
6
11-Apr 18-Apr 25-Apr 2-May 9-May 16-May 23-May 30-May 6-Jun2006
CO
2 & N
2 inj
ecte
d (to
n) /
wat
er p
rodu
ctio
n ra
te (m
3 /d)
0
100
200
300
400
500
600
700
Gas
pro
duct
ion
rate
(m3 /d
)
( ) ( )Gas (m3) Water (m3)
40 days injection• 1.7 – 3.5 tones/day
Low production rates:< 400 m3/day
18
Reservoir Simulation of the 2006 N2Flooding Test
Simulated N2/CO2 injection wellblock
N2 flooding: downhole tubing pressure
14
15
16
ssur
e (M
Pa)
model BHP
Simulated injection wellblock pressure & permeability
13
14
15
16
/ BH
P (M
Pa)
10
100
rmea
bilit
y (m
d)
BHP
pressure
end of N2
fl di
2 2 jpermeability and BHP
11
12
13
0 2 4 6 8 10
N2 injection time (day)
Tubi
ng p
res
Simulated vs. field N2injection BHP
APEC Seminar, AIST, Tsukuba, 7 December 2007
10
11
12
13
0 4 8 12 16 20 24Elapsed time from the start of N2 flooding (day)
Iwel
lblo
ck /
0.1
1
Wel
lblo
ck p
epermeability
flooding
start of CO2
injection
Model Prediction vs Field Data: Pre- and Post- N2 Flooding CO2 Injection Rates
30002
model field (injected amount) field (24-hour rate)
Pre-N2 flooding
Post N2 flooding CO 2 injection rate 20000
0
600
1200
1800
2400
3000
10-Apr 15-Apr 20-Apr 25-Apr 30-Apr 5-May 10-May
2006
Rec
orde
d da
ily a
mou
nt in
ject
ed (m
3 )/ C
O2
inje
ctio
n ra
te (m
3 /d)
Post-N2 flooding
0
4000
8000
12000
16000
20000
0 2 4 6 8 10Injection time (day)
CO
2in
ject
ion
rate
(m3 /d
)
model
field
APEC Seminar, AIST, Tsukuba, 7 December 2007
N2 flooding temporarily improved CO2 injectivity, which declined quickly back to the pre-flooding level (~ 3 tones/ day) after two days.
19
Concluding remarks
• Coalbed reservoirs have unique characteristics: storage, transport and production mechanisms, permeability b h ibehaviour.
• Considerable advances in the reservoir simulation of ECBM, especially in permeability modelling have been made.
• While matrix shrinkage is desirable during primary recovery, CO2 matrix swelling can have a severe impact on coalbed permeability and well injectivity
APEC Seminar, AIST, Tsukuba, 7 December 2007
permeability and well injectivity.
• Long term fate of injected CO2 in coalbeds is uncertain, as CO2, especially at supercritical conditions, reacts with the reservoir rock and fluids.
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