Hydrogeology of a shallow Hydrogeology of a shallow coalbed methane play: A case coalbed methane play: A case study of Ardley coal in weststudy of Ardley coal in west--
central, Albertacentral, Alberta
S.M. Harrison, M.Sc., P.Geol., P.Geo.
SH Consulting Services
In association with NLR Associates Inc.
OutlineOutline
PART I PART I –– Overview and Well DataOverview and Well Data
LocationLocationStratigraphy / HydrostratigraphyStratigraphy / HydrostratigraphyWell Drilling / Completion / Well Drilling / Completion / TestingTestingDataData
PressurePressure““TransmissivityTransmissivity””(permeability)(permeability)Water ChemistryWater Chemistry
PART II PART II –– Production / Production / Development / RegulatoryDevelopment / RegulatoryTesting Testing –– implications for well implications for well spacingspacingLocal Water Well UseLocal Water Well UseQuantity / Quality Produced Quantity / Quality Produced WaterWater
PART III PART III -- Regional ConsiderationsRegional ConsiderationsRegional PressureRegional PressureRegional ChemistryRegional ChemistrySynthesisSynthesisOtherOther
Study LocationStudy Location
Stratigraphic / Hydrostratigraphic Chart
Schematic CrossSchematic Cross--sectionsection
Distribution of coal Distribution of coal –– Plains Area Plains Area (section view; modified AGS(section view; modified AGS--EUB)EUB)
Schematic Cross-sectioncentral Alberta
Horizontal Scale (km) A to B
Vertical Exag. A to B = 25
Precambrian
Paleozoic
Mannville
Lea Park & ColoradoWapiti
Scollard Horseshoe
Canyon Belly
River
Paskapoo
Disturbed Belt
Edmonton
X
X
Cadomin
Brazeau
Coalspur
A B C
A
2000
1000
-1000
-2000
0 030 90
0
C
B
B to C
B to C x 75
Data Data –– Coal Testholes Coal Testholes (red)(red)
High number High number of testholesof testholesData used for Data used for various various mapping mapping themes (e.g. themes (e.g. structure structure contour map contour map showing the showing the distribution of distribution of Ardley coalArdley coal
Data Data –– Hydrochemistry Hydrochemistry (DST)(DST)
Some DSTSome DST’’s s show show ““aa--typicaltypical””water chemistry. water chemistry. e.g. Anomalous e.g. Anomalous DIC (bicarbonate DIC (bicarbonate or HCOor HCO33) ) western part of western part of areaareaIndicator of Indicator of biogenic gas??biogenic gas??Associated Associated sulphate (200 sulphate (200 mg/L)mg/L)Higher gas Higher gas content in parts content in parts of study areaof study area
8-10-047-04 W5M
TargetTarget25
50
75
100
125
150
Coal Zoneapprox. 9 m thick
Paskapoo Fm (lower)
Scollard Fm (Ardley Coal Zone)
Gamma Ray 8-10-47-4 W5M KB = 859 m asl
Gamma Ray
Caliper
Photoelectric Effect
Density Correction
Bulk Densitykg/m3
kg/m3
API
API
150
150
0
0 1900
450 -50
2900
0.0 10.0
175
200
225
250
275
Gamma Ray
8-10-47-4 W5M KB = 859 m asl
Gamma Ray
Photoelectric E ffect
Density Correction
Bulk Densitykg/m3
kg/m3
API
API
150
150
0
0 1900
450 -50
2900
0.0 10.0
200Paskapoo Fm
Scollard Fm
Coal Zone
Well Data Well Data –– what we wanted to what we wanted to evaluate and whyevaluate and why
What:What:PressurePressurePermeabilityPermeabilityWater Chemistry / Water QualityWater Chemistry / Water Quality
Why: Why: Wet or dry coalWet or dry coalBiogenic gas presentBiogenic gas present““ProducibilityProducibility””Regulatory Regulatory
Well 103 Well 103 –– Field MethodsField Methods
Drilling / CompletionDrilling / Completion
Testing / Data Collection Testing / Data Collection
Field Methods: Field Methods: DrillingDrilling
Surface casing setSurface casing setAir/mudAir/mud--drilled to targetdrilled to targetIntermediate casing Intermediate casing cemented at the top of cemented at the top of coal target isolating coalcoal target isolating coalCoal air drilled and Coal air drilled and reamedreamedLiner setLiner setNo well stimulationNo well stimulationWell purged of fluid and Well purged of fluid and allowed to equilibrate allowed to equilibrate for 80 hoursfor 80 hours
Field Methods: Field Methods: Well SetWell Set--up and Testingup and Testing
Well 103 and Well 103 and obs. wellobs. wellDownholeDownholesondessondesPump rate in Pump rate in 103 = 26 103 = 26 mm33/day/day@120 minutes @120 minutes pump gas locks pump gas locks (i.e. end of (i.e. end of ““pumppump--off off ““test)test)““BuildBuild--upup””periodperiod
Well Data: Pressure BuildWell Data: Pressure Build--up Dataup Data
BuildBuild--up up period approx. period approx. 3500 minutes3500 minutesStatic pressure Static pressure head 1470 head 1470 kPakPa(150 m or 50 (150 m or 50 m m btopbtop))
Gas Lock @ 120 min(125 m of drawdown)
Well Data: PermeabilityWell Data: Permeability
CooperCooper--Jacob Jacob SemiSemi--log method log method or or TheisTheisrecoveryrecoveryLate time data Late time data where water where water phase is assumed phase is assumed dominantdominantDefinitely Definitely permeability <5 permeability <5 mDmD (likely <1 (likely <1 mDmD))
gas/water?
Well DataWell DataWater Chemistry/QualityWater Chemistry/Quality
Routine:Routine:NaNa--HCOHCO33 type water, type water, TDS = 1920 mg/LTDS = 1920 mg/LNa = 836 mg/LNa = 836 mg/LClCl = 250 mg/L= 250 mg/LSOSO44 = <5 mg/L= <5 mg/LHCOHCO33 = 1650 mg/L= 1650 mg/L
Trace Metals (dissolved):Trace Metals (dissolved):Low dissolved and total Low dissolved and total dissolved metals (only Fe and dissolved metals (only Fe and MnMn above CCME DWQ above CCME DWQ guidelines)guidelines)
Hydrocarbon (regulated):Hydrocarbon (regulated):No hydrocarbon (e.g. BTEX)No hydrocarbon (e.g. BTEX)
Sodium Adsorption Ratio Sodium Adsorption Ratio (SAR)(SAR)
58 (restricts use as irrigation 58 (restricts use as irrigation water, for example, without water, for example, without upgrade)upgrade)
ECEC3140 3140 µµS/cmS/cm
Isotope GeochemistryIsotope Geochemistry(water and dissolved gas)(water and dissolved gas)
Isotopes:Isotopes:δδ1313CCDICDIC →→ enriched +22 enriched +22 ‰‰δδ1313CCCH4CH4 →→ depleted depleted --46 to 46 to --51 51 ‰‰δδ1818O/O/δδ22H H →→ meteoricmeteoric33HH →→ nonnon--tritiatedtritiated (test(test--well)well)δδ22HHCH4CH4//δδ22HHH2O H2O →→ suggest COsuggest CO22 reduction pathwayreduction pathway
Part I: Summary and ConclusionsPart I: Summary and Conclusions
Detailed compilation of well data pertaining specifically Detailed compilation of well data pertaining specifically to the ACZ (part) hydraulic regime:to the ACZ (part) hydraulic regime:
Chemistry Chemistry –– fresh water <2,000 mg/L TDS; relatively high fresh water <2,000 mg/L TDS; relatively high sodium (Na); high HCOsodium (Na); high HCO3 3 (Na(Na--HCOHCO33 type water)type water)Isotope Isotope GeochemGeochem –– Meteoric; biogenic gas presentMeteoric; biogenic gas presentPressure Pressure –– near normal hydrostatic pressure (water)near normal hydrostatic pressure (water)Permeability Permeability –– low; likely on the order of 1 low; likely on the order of 1 mDmD or lessor less
Part II Part II Production / Development and Production / Development and
RegulatoryRegulatory
Data are important to evaluate reservoir character/flow Data are important to evaluate reservoir character/flow system as it pertains to, for example, development / system as it pertains to, for example, development / production (e.g. quantity/quality of water, well spacing, production (e.g. quantity/quality of water, well spacing, etc.); COetc.); CO22 sequestrationsequestration
Relationship to water wells within the area??Relationship to water wells within the area??
Code of Practice vs. Code of Practice vs. Water ActWater Act
Results Review:Results Review:
DownholeDownholesondessondesPump rate in Pump rate in 103 = 26 103 = 26 mm33/day/day@120 minutes @120 minutes pump gas locks pump gas locks (i.e. end of (i.e. end of test)test)No No ““interference interference effect effect ””
100 m
Recall permeability is relatively low (to water)must “move” water (i.e. depressurize) to attain gas flow
Production / Production / DevelopmentDevelopment
Well Array:Well Array:
Yellow circle Yellow circle = 800 m = 800 m radiusradius
Blue =Blue = water wellswater wells
Red =Red = prodnprodn wellwell(vertical)(vertical)
••Water Act Water Act may be may be applicableapplicable
CBM Working Group / CBM Working Group / Alberta EnvironmentAlberta EnvironmentEUB: EUB:
1. Code of Practice1. Code of Practice2. Div. Approval2. Div. Approval3. No Reporting Required3. No Reporting Required
<5m<5m33/day/dayno reporting requiredno reporting required
Water Well Water Well DistnDistn. .
Blue =Blue = water wellswater wells
Within a 600 m Within a 600 m radius testradius test
Yellow circle Yellow circle –– 800 m radius800 m radius
TestTest--wellwell
Pressure vs. DepthPressure vs. Depth(Test(Test--well 103)well 103)
0
50
100
150
200
2500 500 1000 1500 2000 2500
Pressure (kPa)
Dep
th (m
)
Paskapoo/DriftHydrostatic gradientWell 103
Linear (Hydrostatic gradient)
Data Gap
s
20
40
60
80
80
60
40
20
3
3HC
O
4SO
+ C
l4
8020 40 60
Na + K
COMg
SO
Ca + M
g
C a C l
2 0
4 0
6 0
8 0
2 0
4 0
6 0
8 0
80 60 40 20
80
60
40
20 20
40
60
80
S3
S3
S3
observation well
Paskapoo / Drift
fresh-water
sea water
97 6
10
3
45
8
1
11 2
Piper Plot Piper Plot (water wells and 103)(water wells and 103)
Part III: Regional ConsiderationsPart III: Regional Considerations
Regional PressureRegional PressurePressure vs. DepthPressure vs. DepthHydraulic Head vs. Hydraulic Head vs. ElevationElevationHydraulic Head vs. Hydraulic Head vs. TopoTopoCrossCross--sectionsection
Regional ChemistryRegional ChemistryPiperPiperδδ1818O vs. O vs. δδ22HHδδ22HHH2OH2O vs. vs. δδ22HHCH4CH4
SynthesisSynthesisSummary and Summary and interpretation of datainterpretation of data
FrameworkFrameworkFlowFlowData RequirementsData Requirements
Pressure / Hydraulic HeadPressure / Hydraulic Headlowermost lowermost PaskapooPaskapoo -- ArdleyArdley -- ScollardScollard
Hydraulic Hydraulic Head Head distributiondistributionCrossCross--section linesection lineBB--BB’’
TopoTopo vs. Hydraulic Headvs. Hydraulic Head
correlation with correlation with topography topography ––possibly reflecting possibly reflecting gravity or gravity or topotopodriven flowdriven flow
Topography (KB elevation) vs. Hydraulic Head
y = 0.457x + 401.5R2 = 0.5912
0
200
400
600
800
1000
1200
0 200 400 600 800 1000 1200 1400
Topography (m asl)
Hyd
raul
ic H
ead
(m
Group 1
Group 2
Linear (Group 1)
103
HydrostratigraphicHydrostratigraphic Section BSection B--BB’’
CrossCross--section illustrating relative head differences in lowermost section illustrating relative head differences in lowermost PaskapooPaskapoo –– ArdleyArdley –– ScollardScollard (Groups 1 and 2); break in (Groups 1 and 2); break in hydraulic regime shown as dashed linehydraulic regime shown as dashed line
Section B-B'
0
200
400
600
800
1000
1200
-0.25 0.25 0.75 1.25 1.75 2.25 2.75
Distance (relative)
Elev
atio
n (m
asl
)
TopographyTest Interval Group 1Hydraulic Head Group 1Test Interal Group 2Hydraulic Head Group 2
Well 103
Chemistry Piper DiagramChemistry Piper Diagramlowermost lowermost PaskapooPaskapoo -- ArdleyArdley -- ScollardScollard
Well 103 is NaWell 103 is Na--HCOHCO33 type type waterwaterObsObs well shown well shown for comparison for comparison (reflects higher (reflects higher sulphatesulphate))Water wells are Water wells are CaCa--Mg HCOMg HCO33typetype
δδ1818O O vsvs δδ22HHregionalregional
WaterWater--line (solid) line (solid) for Edmonton for Edmonton Station with Station with GMWL (dashed) GMWL (dashed)
Well 103 plots Well 103 plots along line along line suggesting meteoric suggesting meteoric originorigin
CO2 Reduction
-400-350-300-250-200-150-100-50
0
-200 -150 -100 -50 0
Coleman et al. 1988 Aravena et al. 1995 Aravena et al. 2003 Aravena et al. 2003This Study S3 Martini et al. 2003
δ2Η H2O (‰) VSMOW
δ2 H C
H4 (
‰) V
SMO
W
CO2 reduction trend lineδ2 Η CΗ4 = δ2 Η H2O - 160 +/- 10‰
δδ22HHH2OH2O vs. vs. δδ22HHCH4CH4
COCO22 reduction reduction appears to be appears to be the the methanogenicmethanogenicpathwaypathwayContribution Contribution of biogenic of biogenic gasgas
SYNTHESISSYNTHESISCrossCross--section Bsection B--BB’’
Hydraulic Hydraulic head head distributiondistributionCrossCross--section line section line BB--BB’’
SynthesisSynthesis
Recharging meteoric waters represented by Group 1 (Recharging meteoric waters represented by Group 1 (““PaskapooPaskapoo Water SystemWater System””) ) Regional flow system with local flow components normal or nearRegional flow system with local flow components normal or near--normal pressurenormal pressureBiogenic gas (Biogenic gas (methanogenesismethanogenesis) generation within carbon) generation within carbon--rich rich faciesfacies (coal) leading to (coal) leading to high DIC (i.e. high HCOhigh DIC (i.e. high HCO33 concentrations enriched in concentrations enriched in 1313C)C)GasGas--prone lower system?? prone lower system?? -- significantly significantly underpressuredunderpressured
Section B-B'
0
200
400
600
800
1000
1200
-0.25 0.25 0.75 1.25 1.75 2.25 2.75
Distance (relative)
Elev
atio
n (m
asl
)
TopographyTest Interval Group 1Hydraulic Head Group 1Test Interal Group 2Hydraulic Head Group 2
Well 103
Underpressured?Gas Prone?
18O/2Hmeteoric
CO2 reduction
well 103
511.37 497.9
520.5 568
660m asl
NESW
Paskapoo
Scollard
Scollard
ACZ
Paskapoo
DisturbedBelt Subcrop
08-10-47-04
00/11-01-044-08
02/11-33-046-06
local flow line
regional flow line
00/12-33-046-06
00/05-30-042-09
Gas Prone? Gas Prone?
FlowFlow
Impact??
Impact??18O/2Hmeteoric
18O/2Hmeteoric
Flow details??Flow details??
Local vs. intermediate vs. regionalLocal vs. intermediate vs. regionalAdditional dataAdditional data
Detailed View of theCoal Zone
200
coalzone
Well Log (Detailed View)Well Log (Detailed View)
Scollard?
Haynes Member(?)
H = 805 mTDS = 1920mg/LGas/WaterPerm = 1mDIsotopes (2H, 18O, 13C)
Summary and ConclusionsSummary and Conclusions
Detailed compilation of well data pertaining specifically to theDetailed compilation of well data pertaining specifically to theACZ (part) hydraulic regime:ACZ (part) hydraulic regime:
Chemistry Chemistry –– NaNa--HCOHCO33 type watertype waterPressure Pressure –– near normal pressurenear normal pressurePermeability Permeability –– low likely <1 mDlow likely <1 mD
Synthesis and interpretation of data within regional context Synthesis and interpretation of data within regional context suggests at least parts of the Ardley lie within the suggests at least parts of the Ardley lie within the ““Paskapoo Paskapoo Water SystemWater System”” and have a component of biogenic gasand have a component of biogenic gasData are important to evaluate reservoir character/flow system Data are important to evaluate reservoir character/flow system as it pertains to, for example, production (quantity/quality of as it pertains to, for example, production (quantity/quality of water, well spacing, potential for COwater, well spacing, potential for CO22 sequestration)sequestration)Flow system ?????Flow system ?????
Thank youThank you