Northern Resources Development Applications of whole rock geochemistry and heavy minerals to petroleum exploration in the Bowser and Sustut basins David

Northern Resources DevelopmentApplications of whole rock geochemistry and

heavy minerals to petroleum exploration in the Bowser and Sustut

basins

David RitceyGeological Survey of Canada

[email protected]

Earth Sciences Sector

Northern Resources Development

Ken Ratcliffe

Chemostrat Inc.


Outline

• Sampling Rationale

• Methods of Analysis

• Available Datasets

• Interpretation and Applications


General Strategy and Sample Selection

•Project initiated by EnCana Corporation

•Outcrop samples from GSC field mapping

• all major map-units• multiple lithologies

•Analytical work by EnCana contracted to Chemostrat Inc.


Analyses and Datasets

GEOLOGICAL SURVEY OF CANADAOPEN FILE 5072

2005

D.H. Ritcey, C.A. Evenchick, and K.T. Ratcliffe

GEOCHEMICAL AND HEAVY MINERAL ANALYSESOF THE BOWSER LAKE AND SUSTUT GROUPS,

NORTH CENTRAL BRITISH COLUMBIA, CANADA

Ressources naturelles Canada

Natural Resources Canada

LateJurassic

earlyMiddle

Jurassic

submarine fan and slope shelfdeltaic, fluvial Cache

CreekTerrane

lateMiddle

Jurassic

Cretaceousalluvial fan,fluvial

~20km

~50 km

SW NE

Stikinia

GEOLOGICAL SURVEY OF CANADAOPEN FILE 5072

2005

D.H. Ritcey, C.A. Evenchick, and K.T. Ratcliffe

GEOCHEMICAL AND HEAVY MINERAL ANALYSESOF THE BOWSER LAKE AND SUSTUT GROUPS,




LateJurassic

earlyMiddle

Jurassic


CreekTerrane

lateMiddle

Jurassic


~20km

~50 km

SW NE

Stikinia

GEOLOGICAL SURVEY OF CANADAOPEN FILE ####

2006

M.E. Reichenbach, A.A. Gordon, C.A. Evenchick, and D.H. Ritcey

PETROGRAPHIC DATA AND DESCRIPTIONS OF THE BOWSER LAKE AND SUSTUT GROUPS,




2 mm

GEOLOGICAL SURVEY OF CANADAOPEN FILE ####

2006

M.E. Reichenbach, A.A. Gordon, C.A. Evenchick, and D.H. Ritcey

PETROGRAPHIC DATA AND DESCRIPTIONS OF THE BOWSER LAKE AND SUSTUT GROUPS,




2 mm

•153 samples analyzed by alkali-fusion and ICP-OES & ICP-MS

•7 major element oxides and 37 trace elements

•Heavy mineral separations and grain counts on a subset of 30 sandstones and conglomerates

Data on CD…and free download @ www.gsc.nrcan.gc.ca


Initial presentation and analysis of data

• Stratigraphic assignment of all samples

• 3 lithological groups considered– Conglomerates– Sandstones– Siltstones-claystones

• Age assignment of samples

Geochemistry sample sites:

Brothers Peak Formation

Tango Creek Formation

Devils Claw Formation

Jenkins Creek asemblage

Grounghog-Gunanoot assemblage

Eaglenest assemblage

Muskaboo Creek assemblage

Todagin assemblage

Ritchie-Alger asemblage


Chemostratigraphic approach

• Geochemical characterization of units– “fingerprinting”

• Correlation

• Indicators of provenance

• Geochemical modeling of rock compositions

• Implications for reservoir quality


Chemostratigraphic approach

• Characterize / Distinguish Map Units

Selection of elements:– Empirical– Known relation to provenance, e.g. Cr, Ni from

ultramafics, Ce in allanite

– Relation to mineralogical composition, e.g. K2O and Cs in feldspars and clay minerals


Geochemical Profile

Ce (ppm)

10 50-

Zr/Cr

0 5-

Ce/CrFo

rmat

ion/

assem

blag

e

0 2-

Cr (ppm)

0 550-

Zr (ppm)

0 250-

Ni (ppm)

0 250-

Gro

up

MuskabooCreek

TangoCreek

Ritchie-Alger

Eaglenest

Skelhorne

Sus

tut

BrothersPeak

Bow

ser

Lak

e

Tod

agin


Geochemical Characterization

• Characterization allows classification and correlation

• Contrast Bowser Lake and Sustut groups.

Siltstones-Claystones

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.350

50

100

150

200

250

300

350

Sustut Group

Bowser LakeGroup

Ce/

Lu

Ti/Th

Cr Ce

Zr

Bowser LakeGroup

Sustut Group

Sandstones


Bowser Lake vs Sustut

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Ni (ppm)

80.00

80.00

80.00

80.00

80.00

80.00

80.00

80.00

80.00

80.00 180.00

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!36.00

36.00

36.00

36.00

36.00

36.00

36.00

Ce (ppm)


Variations within Bowser Lake Group

Ce (ppm)

10 50-

Zr/Cr

0 5-

Ce/CrFo

rmat

ion/

assem

blag

e

0 2-

Cr (ppm)

0 550-

Zr (ppm)

0 250-

Ni (ppm)

0 250-

Gro

up

MuskabooCreek

TangoCreek

Ritchie-Alger

Eaglenest

Skelhorne

Sus

tut

BrothersPeak

Bow

ser

Lak

e

Tod

agin


Variations within Bowser Lake Group

0.6

0 30 60 90 120 15020

40

60

80

100

Cr (ppm)

%)

Eaglenestassemblage

Skel

horn

e as

sem

blag

e

Groundhog-Gunanootassemblage

Devils C law Formation& J enkins Creek assemblage

Zr

(ppm

)

Conglomerates

Eaglenest assemblage

Skelhorne assemblage

Groundhog-Gunanoot assemblage

Jenkins Creek assemblage

Devils Claw Formation

3 6 9 12 150.0

0.5

1.0

1.5

2.0

2.5

Na 2

O (

%)

Al2O3 (%)Eaglenest assemblage

J enkins Creekassemblage

Groundhog-Gunanoot

& Skelhorne

assemblages


Provenance Indications

• From Heavy Minerals and from Geochemistry

• Heavy mineral data may be presented in many ways– Profiles– Ratios, indices

Devils ClawFormation

Jenkins Creekassemblage


Ritchie-Algerassemblage

MuskabooCreekassemblage

Skelhorneassemblage

Eaglenestassemblage


gradational contact?

facies relationsuncertain ??

? ?

Todaginassemblage

Cs

Sp

ZrAp

Cs

Zr

Ep

Cs

Cs

Cs

Zr Ap

Cs

ZrAp

Cs

Sustut GrpAp

Ep

TourmalineSpinel (Sp)RutileGarnet

Epidote (Ep)Chrome-spinel (Cs)Apatite (Ap)Anatase

Zircon

Allanite


Provenance Summary

4 main provenance types

• Eaglenest, Skelhorne, Muskaboo Creek, and Todagin are predominantly mafic (-ultramafic)

• Jenkins Creek is acid igneous dominated

• Groundhog-Gunanoot and Ritchie-Alger have mixed provenance

• Sustut Group has metasedimentary provenance (plus acid igneous)

ZrAp

Cs

Cs

Sp

ZrAp

Sustut GrpAp

Ep

Zr Ap

Cs

Cs C s CsCs

Zr

Ep


Provenance Implications

Sedimentary linkages between units

LateJurassic

earlyMiddle

Jurassic


CreekTerrane

lateMiddle

Jurassic


~20km

~50 km

SW NE

Stikinia


Geochemical Modeling

Facies variationDevils ClawFormation



Ritchie-Algerassemblage

MuskabooCreekassemblage

Skelhorneassemblage

Eaglenestassemblage


gradational contact?

facies relationsuncertain ??

? ?

Todaginassemblage

0 5 10 15 20 25 30

0

20

40

60

80

100

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

20

40

60

80

100

3 6 9 12 15

0

20

40

60

80

100

0 50 100 150 200 250

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80

0

10

20

30

40

50

60

70

80

90

100

0.0 0.5 1.0 1.5 2.0

0

10

20

30

40

50

60

70

80

90

100

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

50

60

70

80

90

100

Si/AlU/Al Zr/Al Ni Rb Rb/Ni Na/Al

Dist

al

Dist

a l

Prox

ima l

Prox

ima

l

Devils Claw

Grounhog-Gunanoot

Eaglenest

Ritchie Alger

Tod

agin

J enkinsCreek

MuskabooCreek

SkelhorneFacies trends end - significance ?

plagioclase trend ?Clear differentiation

Clear differentiation

Facies Indicators Differentiation of Eaglesnest and Skelhorne fromGroundhog gunnanoot, J enkins Creek and Devils Claw

Differentiation of Eaglesnest and Skelhorne

40 1000

20

Al2O3

SiO2

Quartz-rich sandstones(Eaglenest, Skelhorne,J enkins Creek, Devils Claw)

argillaceous sandstones(Ritchie-Alger, Todagin,Muskaboo Creek)


Geochemical Modeling

Feldspar abundance

MuskabooCreek

TangoCreek

Ritchie-Alger

Eaglenest

Skelhorne

Su

stut

BrothersPeak

Bo

ws

er L

ake

Toda

gin

Form

ation

/

asse

mbla

geG

roup

Plutonic rock fragmentMetamorphic rock fragmentVolcanic rock fragmentSedimentary rock fragmentCarbonate rock fragmenFeldsparChertPolycrystalline quartzMonocrystalline quartz

0 100 0 32.5 4.0

K2O (%) K2O/RbRb (ppm) Petrography

Sustut Grp

Jenkins Creek

Devils Claw

Ritchie Alger

Todagin

Eagle Nest

Skelhorne

MuskabooCreek

Grounhog-Gunanoot


Implications for Reservoir Quality

• Si/Al applied as a proxy for grain size and clay content

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Bowser

Sustut

Si/Al


Conclusions

• It works!

• Templates can be prepared for stratigraphic classification by geochemistry

• Correlation is practical, effective• Various forms of modeling are feasible• Rapid “first pass” assessment is reasonable,

to prioritize large areas

Documents

Northern Resources Development Applications of whole rock geochemistry and heavy minerals to petroleum exploration in the Bowser and Sustut basins David