Hydrogeology of a shallow coalbed methane play: A case ... · Hydrogeology of a shallow coalbed methane play: A case . study of Ardley coal in west-central, Alberta. ... Gamma Ray

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