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Transcript of Centennial Talk Hydrates
Bureau of Economic Geology
Bureau of Economic Geology Centennial Lecture ProgramBureau of Economic Geology Centennial Lecture Program
DEEP-WATER HYDRATES:
ENERGY POTENTIAL
AND
TECHNICAL CHALLENGES
DEEP-WATER HYDRATES:
ENERGY POTENTIAL
AND
TECHNICAL CHALLENGES
Dr. Bob A. HardageDr. Bob A. Hardage
Bureau of Economic Geology
• First organized research unit of
The University of Texas at Austin
• State Geological Survey of Texas
• One of three units of the
Jackson School of Geosciences
• Staff—140, which includes
80 researchers
• First organized research unit of
The University of Texas at Austin
• State Geological Survey of Texas
• One of three units of the
Jackson School of Geosciences
• Staff—140, which includes
80 researchers
Bureau of Economic GeologyBureau of Economic Geology
Bureau of Economic Geology
• Fossil energy
• Environment
• Outreach
• Advising state and federal government
• Maintaining collections for research:– Cores: 3 repositories, 1,500 miles of core
– Electric logs: 1,000,000 logs in archive
• Fossil energy
• Environment
• Outreach
• Advising state and federal government
• Maintaining collections for research:– Cores: 3 repositories, 1,500 miles of core
– Electric logs: 1,000,000 logs in archive
Full-Time Research MissionFull-Time Research Mission
Bureau of Economic Geology
Bureau Facilities in Austin, TexasBureau Facilities in Austin, Texas
Bureau of Economic Geology
What is hydrate?What is hydrate?
Bureau of Economic Geology
DefinitionsDefinitions
Clathratus: Latin word meaning “enclosed by bars.”
Clathrate: Any compound formed by the inclusion of one
kind of molecule within cavities in the crystal lattice of
another kind of molecule. (No chemical bonds constrain
the trapped molecule.)
Hydrate: A subgroup of clathrates involving gas molecules
trapped inside structured water molecules.
Clathratus: Latin word meaning “enclosed by bars.”
Clathrate: Any compound formed by the inclusion of one
kind of molecule within cavities in the crystal lattice of
another kind of molecule. (No chemical bonds constrain
the trapped molecule.)
Hydrate: A subgroup of clathrates involving gas molecules
trapped inside structured water molecules.
Bureau of Economic Geology
Clathrate Hydrate of Natural GasesStructure I
Clathrate Hydrate of Natural GasesStructure I
Watermolecule
(46)
Methanemolecule
(8)
Modified from Bjørn Kvamme, University of Bergen, Norway
Watermolecule
(46)
Methanemolecule
(8)
Bureau of Economic Geology
The Energy PotentialThe Energy Potential
Bureau of Economic Geology
Size ComparisonsSize Comparisons
One “very fine”mineral grain
One “very fine”mineral grain
One unit volumeof hydrate
One unit volumeof hydrate
Diameter ~ 60μmDiameter ~ 60μm Diameter ~ 6nmDiameter ~ 6nm
1012 unit volumesrequired to fill
the grain
1012 unit volumesrequired to fill
the grain
QAd6959F
Bureau of Economic Geology
Size Comparison of Hydrate Unit Volumeand Typical Pores
Size Comparison of Hydrate Unit Volumeand Typical Pores
QAd6609
Micrograph courtesy Robert G. Loucks, BEG
0.1 mm
Structure I Unit VolumeStructure I Unit VolumeFrio Sandstone
( = 30%)
Frio Sandstone
( = 30%)Pore diameter
~6x10-5m
~1013 unitvolumes ofhydrate inone pore
space
3x10-9m
Bureau of Economic Geology
Hydrates as an Energy SourceHydrates as an Energy Source
QAd6959
Energy densityof LNG
Energy densityof LNG
Energy densityof hydrate
Energy densityof hydrate == 0.420.42
Bureau of Economic Geology
QAd5851
Exposed Structure II Gas HydrateBlock GC 185
Exposed Structure II Gas HydrateBlock GC 185
Orange colorcaused by oilOrange colorcaused by oil
From Sasson and MacDonald (1997)
Bureau of Economic Geology
QAd5901
Deep-Water Oil Seeps and HydrateGulf of Mexico
Deep-Water Oil Seeps and HydrateGulf of Mexico
Oil
Hydrates
Bureau of Economic Geology
The Carrot Dangledby the GovernmentThe Carrot Dangledby the Government
Bureau of Economic Geology
Energy Policy Act of 2005Energy Policy Act of 2005
Sec. 353. Gas Hydrate Production Incentive(b) Suspension of Royalties
(3) Amount of Relief
...The maximum suspension volume shall be30 billion cubic feet of natural gas perlease. Such relief shall be in addition toany other royalty relief under any otherprovision....
Sec. 353. Gas Hydrate Production Incentive(b) Suspension of Royalties
(3) Amount of Relief
...The maximum suspension volume shall be30 billion cubic feet of natural gas perlease. Such relief shall be in addition toany other royalty relief under any otherprovision....
Bureau of Economic Geology
Technical Challenge:
How do you finddeep-water hydrate?
Technical Challenge:
How do you finddeep-water hydrate?
Bureau of Economic Geology
Deep water
Hydrate stability zone
Free-gas zone
Gas/water contact
BSR(Bottom-simulating reflector)
Sea floor
BrightreflectivityExpulsion
crater
Characteristics ofDeep-Water Hydrate Systems
Characteristics ofDeep-Water Hydrate Systems
QAd6937D
Bureau of Economic Geology
BSR Event: Gulf of Mexico, Line ABSR Event: Gulf of Mexico, Line A
Line Bintersection
1.5
2.0
Tim
e (s
)
QAd5890(a)
Bureau of Economic Geology
BSR Event: Gulf of Mexico, Line ABSR Event: Gulf of Mexico, Line A
Line Bintersection
1.5
2.0
Tim
e (s
)
QAd5890
Bureau of Economic Geology
Deep water
Hydrate stability zone
Free-gas zone
Gas/water contact
BSR(Bottom-simulating reflector)
Sea floor
BrightreflectivityExpulsion
crater
Characteristics ofDeep-Water Hydrate Systems
Characteristics ofDeep-Water Hydrate Systems
QAd6937D
Bureau of Economic Geology
Profile 549
A. Carbonate-cemented shells
B. Layered clam shells
Study Site 2: Genesis Field AreaBlock GC 205
Study Site 2: Genesis Field AreaBlock GC 205
QAd6510
Bureau of Economic Geology
Technical Challenge:
How do you evaluatethe resource?
Technical Challenge:
How do you evaluatethe resource?
Bureau of Economic Geology
The Expensive Option:
Drill a well.
The Expensive Option:
Drill a well.
Bureau of Economic Geology
GR (API)
30 80 1.1 0.7 1.61.9 1.5 1.9
Bulk-density Velocity Resistivityg/cm3 km/sec ohm-m
Hydrate
~0.2-m400
600
500
300
200
Dep
th b
elo
w s
eafl
oo
r (m
)
Paull and others (1996)
Hydrate Log Data: Blake Ridge (ODP 995)Hydrate Log Data: Blake Ridge (ODP 995)
QAd5173
Bureau of Economic Geology
A More Attractive Option:
Develop a remote, large-areaevaluation technology
(seismic imaging?).
A More Attractive Option:
Develop a remote, large-areaevaluation technology
(seismic imaging?).
Bureau of Economic Geology
VSP OBC/OBSVibrator
Well
Air gun
Deep water
Similar geometry
Seafloor
Sea level
Multicomponentsensor
Multicomponentsensor
Sourcestation
Sourcestation
VSP AND DEEP-WATER OBC/OBS DATA ACQUISITION:SIMILAR ELEVATION DIFFERENCES BETWEEN
SOURCES AND RECEIVERS
VSP AND DEEP-WATER OBC/OBS DATA ACQUISITION:SIMILAR ELEVATION DIFFERENCES BETWEEN
SOURCES AND RECEIVERS
QAd4647
Bureau of Economic Geology
4-C OBC COMMON-RECEIVER GATHER, CDP 13949,LINE 549, BLOCK 204 (50-m SHOT SPACING)
4-C OBC COMMON-RECEIVER GATHER, CDP 13949,LINE 549, BLOCK 204 (50-m SHOT SPACING)
QAd4171
Bureau of Economic Geology
COMMON-RECEIVER GATHERS IN REDUCED-TIME FORMATWITH SPHERICAL DIVERGENCE CORRECTION
COMMON-RECEIVER GATHERS IN REDUCED-TIME FORMATWITH SPHERICAL DIVERGENCE CORRECTION
QAd4172
Bureau of Economic Geology
BASIC RESPONSES OF OBC SENSORSBASIC RESPONSES OF OBC SENSORS
QAd4170
Bureau of Economic Geology
SEPARATING DOWNGOING AND UPGOING WAVEFIELDSSEPARATING DOWNGOING AND UPGOING WAVEFIELDS
QAd4175
Bureau of Economic Geology
Hydrophone/15 (P) Vertical geophone (Z)
2.0
1.5
1.0
0.5
-2000 0 2000
Tim
e (s
)
Tim
e (s
)
2.0
1.5
1.0
0.5
-2000 0 2000
Source offset (m) Source offset (m)
GAS HYDRATE OBC VSP EXAMPLE 1GAS HYDRATE OBC VSP EXAMPLE 1
QAd4612x
Bureau of Economic Geology
Down wave Up wave
2.0
1.5
1.0
0.5
-2000 0 2000
Tim
e (s
)
Tim
e (s
)
2.0
1.5
1.0
0.5
-2000 0 2000
Source offset (m) Source offset (m)
SEPARATION OF DOWN AND UP WAVEFIELDS:COMMON-RECEIVER GATHER, WATER DEPTH = 871 M
SEPARATION OF DOWN AND UP WAVEFIELDS:COMMON-RECEIVER GATHER, WATER DEPTH = 871 M
SEPARATION OF DOWN AND UP WAVEFIELDS:COMMON-RECEIVER GATHER, WATER DEPTH = 871 M
P + Z / cos() P - Z / cos()
QAd4613x
Bureau of Economic Geology
Seafloor
0.5
0.3
0.1
0
-2000 0
Tim
e (s
)
Source offset (m)
0.4
0.2
2000
P-P REFLECTIVITY: SEAFLOOR DATUMP-P REFLECTIVITY: SEAFLOOR DATUM
(1) Reflectivity (f) =Up wave (f)
Down wave (f)
+(2) Damping
+(3) Inverse Fourier transform
+(4) Time derivative
QAd4614x
Bureau of Economic Geology
HORIZON-ORIENTED STATIC CORRECTIONS: IDEAL FORANGLE-DEPENDENT REFLECTIVITY AND VELOCITY ANALYSIS
HORIZON-ORIENTED STATIC CORRECTIONS: IDEAL FORANGLE-DEPENDENT REFLECTIVITY AND VELOCITY ANALYSIS
Pre-NMO
3.5
2.5
1.0
0
-2000 0 2000
Tim
e b
elo
w s
eafl
oo
r (s
)
Source offset (m)
0.5
1.5
2.0
3.0
ddt
(PP) Static corrected
-2000 0 2000Source offset (m)
0.24
0.20
0.16
0.08
Tim
e b
elo
w s
eafl
oo
r (s
)
0.12
QAd4620x
Target event
Bureau of Economic Geology
COMPARISON OF DYNAMIC CORRECTIONS AND HORIZON-ORIENTED STATIC CORRECTIONS, WATER DEPTH = 871 MCOMPARISON OF DYNAMIC CORRECTIONS AND HORIZON-ORIENTED STATIC CORRECTIONS, WATER DEPTH = 871 M
QAd4619x
Static corrections Dynamic corrections
0.24
0.20
0.16
0.08
-2000 0 2000
Tim
e b
elo
w s
eafl
oo
r (s
)
-2000 0 2000
Source offset (m) Source offset (m)
0.12
0.24
0.20
0.16
0.08
Tim
e b
elo
w s
eafl
oo
r (s
)
0.12
Bureau of Economic Geology
NMO-CORRECTED COMMON-RECEIVER GATHER WITHDEPTH-POINT-OFFSET OVERLAY, WATER DEPTH 871 MNMO-CORRECTED COMMON-RECEIVER GATHER WITHDEPTH-POINT-OFFSET OVERLAY, WATER DEPTH 871 M
QAd4618x
0.35
0.25
0.15
0.10
-2000 0
Tim
e b
elo
w s
eafl
oo
r (s
)
0.30
0.20
20001000-1000
0.05
0
Source offset (m)
Depthpointoffset
10 m
85 m
160 m
Bureau of Economic Geology
CONSTRUCTING P-P IMAGE WITH VSP MINI-IMAGESCONSTRUCTING P-P IMAGE WITH VSP MINI-IMAGES
Bureau of Economic Geology
BASIC RESPONSES OF OBC SENSORSBASIC RESPONSES OF OBC SENSORS
QAd4170
Bureau of Economic Geology
ISOLATING THE P-SV MODEISOLATING THE P-SV MODE
HL = Hemipelagic layer
QAd4177
Bureau of Economic Geology
QAd4179
Before After
EMPHASIZING P-SV EVENTS, LINE 549, BLOCK GC204EMPHASIZING P-SV EVENTS, LINE 549, BLOCK GC204
Bureau of Economic Geology
QAd4181
ESTIMATION OF P-SV REFLECTIVITYESTIMATION OF P-SV REFLECTIVITY
Bureau of Economic Geology
QAd4771
PS DATA, PS DATA, DYNAMIC TIME CORRECTIONSDYNAMIC TIME CORRECTIONS
PS DATA, PS DATA, DYNAMIC TIME CORRECTIONSDYNAMIC TIME CORRECTIONS
Bureau of Economic Geology
CONSTRUCTING P-SV IMAGE WITH VSP MINI-IMAGESCONSTRUCTING P-SV IMAGE WITH VSP MINI-IMAGESCONSTRUCTING P-SV IMAGE WITH VSP MINI-IMAGESCONSTRUCTING P-SV IMAGE WITH VSP MINI-IMAGES
QAd5877
Bureau of Economic Geology
Comparison of PP ImagesComparison of PP Images
QAd4760
Receiver number50 100 150
PP image (5-m spacing)
350
0
50
100
150
200
250
300
Receiver number50 100 150
Production PP (12.5-m CDP)
350
0
50
100
150
200
250
300
Seafloor
Expulsionchimney
Expulsionchimney
4 km4 km
Red
uce
d t
ime
(ms)
PP
tim
e (m
s)
Bureau of Economic Geology
Raw data
Flattened to seafloor
1000 m
Expulsionchimney
South North
0 1000
Chirp trace number4000 50002000 3000 6000
60
10
0
30
50
40
20
Chirp Sonar Data, Line 549Chirp Sonar Data, Line 549
Tim
e (m
s)
QAd4234(a)
Bureau of Economic Geology
Comparison of P-SV Image withAUV P-P Image
Comparison of P-SV Image withAUV P-P Image
PS
tim
e (m
s)
Vp
/Vs
= 3
4
PP
tim
e
(m
s)
Receiver number
Chirp-sonar (25-m spacing)
0
5
10
Receiver number
New PS processing
350
0
50
100
150
200
250
300
400
450
20
2520 100 16040 60 80 120 140 20 100 16040 60 80 120 140
15
Vp/Vs-50 -50
58
Seafloor
34
27
Unconformity
R014
4 km4 km
surface
QAd4767
Bureau of Economic Geology
GR (API)
30 80 1.1 0.7 1.61.9 1.5 1.9
Bulk-density Velocity Resistivityg/cm3 km/sec ohm-m
Hydrate
~0.2-m400
600
500
300
200
Dep
th b
elo
w s
eafl
oo
r (m
)
Paull and others (1996)
Hydrate Log Data: Blake Ridge (ODP 995)Hydrate Log Data: Blake Ridge (ODP 995)
QAd5173
Bureau of Economic Geology
ACCURACY OF INTERVAL VP (< 1%?)ACCURACY OF INTERVAL VP (< 1%?)
Bureau of Economic Geology
Technical Challenge:
You have to know the morphology if velocity is
used to estimatehydrate concentration
Bureau of Economic Geology
Hydrate/Sediment Grain-to-Grain Morphology Models
Model C:Layered, Solid Phase
Model D:Layered, Disseminated Phase
Model A:Disseminated, Load-bearing
Model B:Disseminated, Non-Load-Bearing
Sediment
Hydrate
QAd4571
Bureau of Economic Geology
Model-Based Vp, Host Sediment = Sand, Porosity = 0.37
0 0.1 0.2 0.3 0.41500
2000
2500
3000
3500
4000
Vp
[m
/s]
Model C:Layered, Solid Phase
0 0.1 0.2 0.3 0.41500
2000
2500
3000
3500
4000
Vp
[m
/s]
Cgh = volume fraction of gas hydrate
Model D:Layered, Disseminated Phase
0 0.1 0.2 0.3 0.41500
2000
2500
3000
3500
4000V
p [
m/s
]
Model A:Disseminated, Load-bearing
0 0.1 0.2 0.3 0.41500
2000
2500
3000
3500
4000
Vp
[m
/s]
Model B:Disseminated, Non-Load-Bearing
Fast
Slow
Fast
Slow
cgh cgh
QAd4572
Bureau of Economic Geology
Hydrate Cores: Offshore Korea7
8 c
m
6 cm Load-bearing Veins
QAd6545
Bureau of Economic Geology
The BiggestTechnical Challenge:
How do you producethe hydrate?
Bureau of Economic Geology
Stability Domains: Hydrate, Ice, Methane
A B
100
200
500
1000
2000
10
50
100
200
Hydrate +water + gas
A B
Hydrate/gasphase boundary
Gas+water
Hydrate+ice+gas
Gas+ice Ice/water phase boundary
10-10 0 20 30 40Temperature (°C)
Dep
th (
m)
Pre
ssu
re (
atm
)
QAd4240
A = D ir ec t io n p h as e b o u n d ary sh ifts if Na C l o r N 2 is a d d edB = D ir ec tio n p h ase b o u n d a ry sh ifts if C O 2 , H 2S , C 2H 6 , o r C 3H 8 is ad d ed
Modified from Kvenvolden (1998)
Bureau of Economic Geology
So, how do we summarizethe technical challenges?
Bureau of Economic Geology
“Reports that say that something hasn’thappened are always interesting to me,because as we know, there are known knowns; there are things we know we know.We also know there are known unknowns; that is to say we know there are things we know we don’t know. But there are also unknown unknowns — the ones we don’t know we don’t know.”
Donald RumsfeldDepartment of Defense News BriefingFebruary 12, 2002
Bureau of Economic Geology
ACKNOWLEDGEMENTACKNOWLEDGEMENT
● U.S. Department of EnergyContract DE-FC26-05NT42667
● Minerals Management ServiceContract 1435-01-05-CT-39388
● U.S. Department of EnergyContract DE-FC26-05NT42667
● Minerals Management ServiceContract 1435-01-05-CT-39388
Hydrate research funded by:Hydrate research funded by: