improved application of gas reservoir parameters
DESCRIPTION
Technology Transfer Update. Improved Application of Gas Reservoir Parameters. ACARP Project C10008 May 10 th 2002 Mackay. The Team.…. Applicant Organisation - GeoGAS Systems Pty. Ltd. Ray Williams, Eugene Yurakov Supporting Organisations – CSIRO Energy Technology North Ryde - PowerPoint PPT PresentationTRANSCRIPT
Improved Application of Gas Reservoir Parameters
ACARP Project C10008May 10th 2002
Mackay
Technology Transfer Update
GeoGAS
The Team.… Applicant Organisation - GeoGAS Systems Pty.
Ltd.Ray Williams, Eugene Yurakov
Supporting Organisations – CSIRO Energy Technology North Ryde
Abou Saghafi Multiphase Technologies Pty. Ltd.
David Casey James Cook University
Peter Crosdale $141,159 1 Year
Objectives
Improving the quality of input data in key areas.
Obtaining a clearer understanding of the combined
effects of sets of gas reservoir parameters.
Producing a set of sensitivity matrices that can be
used as an improved guide in modelling and in
identification of the most important data to acquire.
From the ACARP Submission
“……… the importance of considering the
gas implications is widely recognised.
What is not generally recognised, is the
variability in the gas reservoir and the
processes and limitations of the tools
available to undertake modelling
assessments.”
Parameter Sensitivity of results to parameter
Obtaining likelihood
Low Middle High Low Middle High Seam dimensions
Roadway dimensions Gas composition
Porosity Permeability
Langmuir isotherm Desorption time constant
Desorption pressure Reservoir temperature
Gas content Relative permeability
Pore pressure Compressibility
Matrix shrinkage Pore pressure
Transmissibility
From GeoGAS/CSIRO SIMED Procedure Manual 1998
For this project we look mainly at:
Gas sorption isotherms Use of multiphase testing to:
Validate gas sorption isotherms Generate relative permeability curves
Assess desorption time constant Gas drainage borehole recharge Other important stuff –
Permeability, porosity, compressibility Sensitivity analyses
An Example – The Isotherm Shock
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
adso
rbed (m
3/t)
GeoGAS 16.9% Ash
GeoGAS 13% Ash
CSIRO 12.1% Ash
CSIRO 8.9% Ash
CSIRO 12.8% Ash
58-36.xls
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250 300
GeoGAS Isotherm
CSIRO Isotherm
Start of Comparisons
0
5
10
15
20
25
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3/t
)
CSIRO
GeoGAS
JCU
0
5
10
15
20
25
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3 /t
)
CSIRO
GeoGAS
JCU
Isotherm Comparison Tests – Factors Considered
Method – all essentially the same (gravimetric)
Grainsize distribution of tested coal Moisture before during and after
testing, including equilibrium moisture Consistency between distributed
samples
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
14.5% Ash, 2.3% Moisture GeoGAS
15.6% Ash, 2% Moisture JCU up to 5 kPa
15.5% Ash, 1.8% Moisture CSIRO
09
10
11
41
42
43
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
10.3% Ash, 2.3% Moisture GeoGAS
9.2% Ash, 1.9% Moisture JCU up to 5 kPa
9% Ash, 1.9% Moisture CSIRO
09
10
11
41
42
43
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
17.7% Ash, 2.4% Moisture GeoGAS
18.2% Ash, 1.9% Moisture JCU up to 5 kPa
19.1% Ash, 1.9% Moisture CSIRO
09
10
11
41
42
43
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
26.6% Ash, 3.2% Moisture GeoGAS
25.1% Ash, 2.9% Moisture JCU up to 5 kPa
25.1% Ash, 2.8% Moisture CSIRO
09
10
11
41
42
43
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
10.5% Ash, 3.7% Moisture GeoGAS
9.3% Ash, 3.5% Moisture JCU up to 5 kPa
10% Ash, 3.4% Moisture CSIRO
09
10
11
41
42
43
Methane Isotherm Comparison
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
11% Ash, 3.8% Moisture GeoGAS
14.2% Ash, 3.8% Moisture JCU up to 5 kPa
11.4% Ash, 3.4% Moisture CSIRO
09
10
11
41
42
43
Density Comparisons of Sub Samples
Isotherms shown to be quite sensitive to density. A change of 0.1 g/cc results in around 6-18% change in sorption capacity. Replots by Crosdale
and Yurakov showed reduced scatter using the same density. Coal density inconsistencies identified as probably the most significant
contributor to isotherm differences.
Relative Densities (g/cc)
Adsorbed CH4 DensitiesCSIRO 0.415 g/cc
GeoGAS 0.6189 g/ccJCU 0.3196 g/cc
Laboratory 9 10 11 41 42 43 Average
GeoGAS 1.39 1.40 1.32 1.64 1.41 1.41 1.43
JCU 1.45 1.50 1.52 1.59 1.47 1.46 1.50
CSIRO 1.35 1.41 1.40 1.59 1.41 1.37 1.42
Grainsize Comparison
Particle size distribution @ "100 mm lens"
0
1
2
3
4
5
6
7
8
9
<0.
54
0.54
-0.6
5
0.65
-0.7
9
0.79
-0.9
5
0.95
-1.1
5
1.15
-1.3
9
1.39
-1.6
8
1.68
-2.0
4
2.04
-2.4
7
2.47
-2.9
9
2.99
-3.6
1
3.61
-4.3
7
4.37
-5.2
9
5.29
-6.4
6.4-
7.75
7.75
-9.3
8
9.38
-11.
35
11.3
5-13
.74
13.7
4-16
.63
16.6
3-20
.13
20.1
3-24
.36
24.3
6-29
.49
29.4
9-35
.69
35.6
9-43
.19
43.1
9-52
.28
52.2
8-63
.28
63.2
8-76
.59
76.5
9-92
.7
92.7
-112
.2
112.
2-13
5.8
135.
8-16
4.36
>16
4.36
Grain Size Bin (micron)
Siz
e D
istr
ibu
tio
n (
%)
CSIRO
Geogas
JCU
WYO109
WYO110
WYO111
NW0141
NW0412
NW1043
JCU Isotherm "As Received" and "Equilibrium Moisture" Assessment
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Ga
s a
ds
orb
ed
(m
3 /t)
18.2% Ash, 1.9% Moisture JCU up to 5 kPa
18.2% Ash, 1.9% Moisture JCU up to 7 kPa
18.2% Ash, 2.1% Moisture JCU Eq.Mosture up to 5 kPa
18.2% Ash, 2.1% Moisture JCU Eq.Mosture up to 7 kPa
09
10
11
41
42
43
IsothermsField-Lab Desorption Pressure Comparisons
0
500
1000
1500
2000
2500
3000
3500
4000
0 1 2 3 4 5
Elapsed Time (hrs)
Bo
tto
mh
ole
Pre
ssu
re (
kPa
)
0
0.05
0.1
0.15
0.2
0.25
Wa
ter
& G
as
Pro
dcu
tio
n R
ate
(li
tre
s/m
in)
Stage 1 Stage 2 Stage 3
From Multiphase Technologies Pty. Ltd.David Casey
0
5
10
15
20
25
30
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3 /t
)
Match Good?
1375 kPa - Lab Test
1241 kPa - Field
9.85 m3/t
GeoGAS
CSIRO
CH4 Grosvenor Desorption Pressure During Well Production
0
500
1000
1500
2000
2500
3000
0 5 10 15 20 25
Time (days)
Pre
ssu
re W
ater
Co
lum
n (
kPa)
GR#5
GR#4
GR#3
Comparison Desorption Pressures – Well, Multiphase, Laboratory
Methane Isotherm Goonyella Middle Seam Borehole GR01
0
5
10
15
20
25
30
0 500 1000 1500 2000 2500 3000 3500
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3 /t
)
GRO0077, 13.4% AshGRO0074, 9.4% AshLab Test Desorption PressureMP Field Desorption PressureWell Desorption Pressure
0
2
4
6
8
10
12
14
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3/t
)
11.2% Ash
10.7% Ash
Lab Test Desorption Pressure
Field Desorption Pressure
2058 kPa - Lab Test
2101 kPa - Field
8.71 m3/t
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Absolute Pressure (kPa)
Gas
ad
sorb
ed (
m3 /t
)24.2% Ash
Lab Test Desorption Pressure
Field Desorption Pressure
746 kPa - Lab Test
451 kPa - Field
6.43 m3/t-800
-600
-400
-200
0
200
400
very
hig
h
high
mod
erat
e
mod
erat
e
mod
erat
e
low
low
low
very
low
very
low
Decreasing Permeablity -->
Fie
ld -
Lab
Des
orp
tio
n P
ress
ure
(kP
a)
DesP-Summary.xls
Idea is to back out relative permeability curves from history matching water and gas production
Have had difficulty doing this with SIMED in moderate to high permeability coal.
Same problem using EclipseCBM Have contracted Molopo (Wang Xingjin) to further SIMED curve matching
Matching per se is not the problem, it is getting a matchusing sensible parameters that is proving difficult……..
History Match for Cumulative Gas Production and Bottom Hole Pressure
0
5
10
15
20
25
30
35
40
45
50
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50
Time (days)
Cu
mu
lati
ve
Ga
s P
rod
uc
tio
n (
Lit
re)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
wa
ter
Ra
te m
3/d
ay
) B
ott
om
Ho
leP
res
su
re (
10
00
Kp
a)
Simu. Cumu. Gas
Actual Cummulative Gas
Actual BHP
Simu. BHP
(Og34.dat)Fig. 2
Thickness: 2.22 mPi 1460 KpaPorosity 0-10.25 m 2% 10.25-17.78 m 1.2% > 17.78 m 1%Gas Content 7.9 m3/tVl=26.9 m3/t, Pl=2001 KpaPd=830 Kpa, Tau= 25 dayspermeability: 0-10.25 m 10 md 10.25-17.78m 2.5 md >17.78 0.55 md
History Match Profile
0
0
0
1
1
1
1
1
2
2
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50
Time (days)
Cu
mu
lati
ve
Ga
s P
rod
uc
tio
n (
Lit
re)
Simu. Water
Actual Water Production
(Og34.dat)
The water rate in the input data file was set as actual data
Fig. 1
Thickness: 2.22 mPi 1460 KpaPorosity 0-10.25 m 2% 10.25-17.78 m 1.2% > 17.78 m 1%Gas Content 7.9 m3/tVl=26.9 m3/t, Pl=2001 KpaPd=830 Kpa, Tau= 25 dayspermeability: 0-10.25 m 10 md 10.25-17.78m 2.5 md >17.78 0.55 md
History Matched Relative Permeabi l i ty
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1
Water Saturation
Rel
ativ
e P
erm
eab
ilit
y
Fi g. 3
Gas
Water
Parameters varied are:- porosity- permeability- sorption time constant- relative permeability
What is tau? Supposedly, the time taken for 63.2% of gas to
desorb from a slow desorption gas content test
Where = desorption time constant
= coal matrix shape factor
D = diffusion coefficient
DteQ
Q
10
632.0110
eQ
Q
D 1
But is it 63.2% of Qm, Q1+Q2 or just Q2? We have related tau (from Qm) to IDR30.
y = 4.243800x-0.349979
R2 = 0.457498
0
2
4
6
8
10
12
14
16
18
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
IDR30
Tau
Assessed the variability
For a particular study area, define a range of tau’s applicable to the gas content magnitude for that deposit for use in sensitivity assessments
y = -0.349979x + 1.445459
R2 = 0.457498
0
0.5
1
1.5
2
2.5
3
3.5
4
-4 -3 -2 -1 0 1 2
Ln IDR30
Ln
Tau
Qm mean Tau hi Tau mean Tau low3.36 23.8 9.5 3.8
4.58 18.7 7.5 3.06.81 13.5 5.4 2.2
8.50 10.7 4.3 1.79.47 9.2 3.7 1.510.01 8.3 3.3 1.310.38 7.7 3.1 1.210.63 7.2 2.9 1.2
10.83 6.9 2.7 1.1
At low perm (1mD, almost no difference between tau 4.5 and tau 30 days (8.5 m3/t)
MG Drainage Options
B HdgA Hdg
0
1
2
3
4
5
6
7
8
9
200 225 250 275 300 325 350 375 400 425 450 475 500
Distance From MG (m)
Gas
Co
nte
nt
(m³/
t)
1 mD 1 mD tau 30 days Gas Content Assistance Line Initial Gas Content Lateral Distance
20 days on line 100 md tau 4.5
Lateral Distance 15 m from B Hdg Qm Line @ 4 m3/t
640 days on line 1 md tau 4.5 days
640 days on line 1 md tau 30 days
Perm.xls{Change in Gas Content}
20 days on line 100 md tau 30
At high perm (100 mD, big difference between tau 4.5 and tau 30 days (8.5 m3/t)
MG Drainage Options
B HdgA Hdg
0
1
2
3
4
5
6
7
8
9
200 225 250 275 300 325 350 375 400 425 450 475 500
Distance From MG (m)
Gas
Co
nte
nt
(m³/
t)
100 mD tau 30 Gas Content Assistance Line Initial Gas Content Lateral Distance 100mD tau 4.5 days
20 days on line 100 md tau 4.5
Lateral Distance 15 m from B Hdg Qm Line @ 4 m3/t
640 days on line 1 md tau 4.5 days
640 days on line 1 md tau 30 days
Perm.xls{Change in Gas Content}
20 days on line 100 md tau 30
Gas drainage efficiency diminishesGas drainage efficiency diminishestoward the end of boreholes,toward the end of boreholes,Not from the end…Not from the end…
0
2
4
6
8
10
200 250 300 350 400 450 500
Distance from previous maingate (m)
Gas
con
tent
(m
3/t)
25 m spacing, 95 days drainage
50 m spacing, 240 days drainage
100 m spacing, 720 m drainage
Line of "barrier"10 m off B Hdg
Initial gas content
Cross panel borehole A Hdg B Hdg
Effective end of borehole 30 moff B Hdg rib
A H
eadin
g
B H
eadin
g
Lin
e o
f barr
ier
EffectEffectOf HoleOf HoleSpacingSpacing
0
2
4
6
8
10
200 250 300 350 400 450 500
Distance from previous maingate (m)
Gas
con
tent
(m
3/t)
Permeability 10 mD in X& 2 mD in Y directions
Permeability 10 mD in X& 10 mD in Y directions
Permeability 2 mD in X &10 mD in Y directions
Line of "barrier"10 m off B Hdg
Initial gas content
Cross panel borehole A Hdg B Hdg
Effective end of borehole 30 moff B Hdg rib
A H
eadin
g
B H
eadin
g
Lin
e o
f barr
ier
Effect OfEffect OfDirectionalDirectionalPermeabilityPermeability
xx
yy
A H
eadin
g
B H
eadin
g
Lin
e o
f barr
ier
Effect OfEffect OfPorosityPorosity
xx
yy
MG Drainage Options
B HdgA Hdg
0
1
2
3
4
5
6
7
8
9
200 225 250 275 300 325 350 375 400 425 450 475 500
Distance From MG (m)G
as C
on
ten
t (m
³/t)
1% 2% 3% Gas Content Assistance Line Initial Gas Content Lateral Distance
150 Days on LineLateral Distance 15 m from B Hdg Qm Line @ 4 m3/t 150 Days on Line 150 Days on Line
Poro.xls{Change in Gas Content}
Conclusions Hope to bring project to a close in next couple of months Scope to improve understanding and standardisation
between labs on isotherm testing. Need to evaluate combinations of parameters eg as we
did for ranges of tau at low and high permeabilities. A wider range of field measurements is important to lock
down parameters. Eg measurement of both water and gas flow from in-seam boreholes greatly improves the robustness of the modelling.
The bottom line is to create more robust modelling that is relevant. That means:- better input data- good modelling packages. - defining the approach to modelling that includes being critical every inch of the way, quantifying uncertainty……..