Looking at Trenton– Looking at Trenton– Black River Black River Reservoirs: Reservoirs: Outcrops Analogs in Outcrops Analogs in Kentucky Kentucky Dave Harris Kentucky Geological Survey University of Kentucky
Dec 18, 2015
Looking at Trenton–Black Looking at Trenton–Black River Reservoirs:River Reservoirs:
Outcrops Analogs in Outcrops Analogs in KentuckyKentucky
Dave Harris
Kentucky Geological Survey
University of Kentucky
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# Black River Production# Trenton Production
R O M E
T R O U G H
OutlineOutline
• Trenton/Black River in Kentucky
• NYSERDA project at KGS and NYSM
• Tectonic dolomite examples from outcrops and shallow cores
Chronostratigraphic Units
Global NorthAmerican
System/Series
Series Stage
DrakesFm
BullForkFm
AshlockFm
GrantLake
Limestone
CallowayCreek FmGarrard Slts.
Fairview/Leipers
Fm
ClaysFerry Kope
LexingtonLimestone
High BridgeGroup
QueenstonFm
LorraineGroup
Utica Fm
TrentonGroup
Black RiverGroup
JuniataFm
TrentonLimestone
Black RiverGroup
Central andEastern
Kentucky
WestVirginiaEastern
Ohio
New York
Upper and MiddleUpper and Middle OrdovicianOrdovicianStratigraphyStratigraphy
Units affected byfault-controlleddolomitization
CUMBERLAND HARLAN EXPL 1 SHUMATE HEIRSAPI No.: 1619787816
08-P-67 POWELL CO, KY
Gamma Ray (GR)0 200 (GAPI)
Caliper (CALI)6 16 (in)
M.D
EP
TH (ft)
100200300400500600700800900
1000110012001300140015001600170018001900
Bulk Density (RHOB)
2 3(g/cc)
Neutron (NPHI)0.3 -0.1(pu)
T. Ordovician
Lexington Ls(Trenton)
High Bridge Gp(Black River)
Wells Creek FmKnox Gp
Type LogType LogUpper and MiddleUpper and Middle
Ordovician,Ordovician,Central KentuckyCentral Kentucky
30 0 30 60 90 Miles
GeologyWATERALLUVIUMTERTIARYCRETACEOUSPENNSYLVANIANMISSISSIPPIANDEVONIANSILURIANORDOVICIAN
Surface Faults
Study AreaStudy Area
Ordovician oil shows, central Ky.Ordovician oil shows, central Ky.
Lexington Ls. (Trenton)Lexington Ls. (Trenton)Walker Quarry, Montgomery Co., Ky.Walker Quarry, Montgomery Co., Ky.
Calloway Creek Fm Calloway Creek Fm (dolomitized),(dolomitized),Clark Co., Ky.Clark Co., Ky.
Why look at outcrops in Why look at outcrops in Kentucky?Kentucky?• Regional scale
– Understand distribution of tectonic dolomite– Timing of faulting, dolomitization, and
hydrocarbon migration
• Local scale– Reservoir scale porosity and permeability
distribution– Depositional facies controls
Need Better Geological ModelNeed Better Geological Model
• Model for dolomitization process– Stratigraphic control on dolomite– Structural control on dolomite– Source/pathways for fluids
• Timing of dolomitization– relation to hydrocarbon migration
• Hydrocarbon source
NYSERDA ProjectNYSERDA Project• 2-year project to study central Kentucky
dolomites and apply results to subsurface N.Y. dolomite reservoirs
• Co-funded by Triana Energy, KGS and U.S. DOE
• Focus: outcrops and new continuous cores
• Approach: petrography, geochemistry, shallow high-resolution seismic, integration with New York reservoirs
NYSERDA (cont.)NYSERDA (cont.)
• Geochemical techniques– oxygen and carbon stable isotopes– microprobe (trace elements)– fluid inclusions (salinity and temperature)
• Cores: 2 continuous cores through Trenton and Black River to top Knox
Integration with New York Integration with New York ReservoirsReservoirs• Collaborating with T. Smith at the NYSM• Data to be compared with similar work
on New York rocks• DOE funding shallow seismic acquisition
in central Kentucky• P-wave and shear wave sources to
image shallow dolomites
Tectonic Dolomite OutcropsTectonic Dolomite Outcrops
• Hydrothermal mineralization present in central Kentucky: barite, galena, sphalerite, saddle dolomite
• Upper Ordovician limestones replaced by dolomite adjacent to faults in outcrop
• Black et al., (1981 USGS Professional Paper 1151A) mapped 33 T-dolomites
From Black and others, 1981
Ordovician Dolomite LocalitiesOrdovician Dolomite Localities
Top Black River shaded relief
Fault-controlled dolomite,Fault-controlled dolomite,
Clark Co., Ky.Clark Co., Ky.
From Black et al., 1981
Fracture-fill in core CK-15Fracture-fill in core CK-15stained with alizarin-redstained with alizarin-red
calcite
barite or celestite
calcitedolomite
Jeptha Knob, Jeptha Knob, Shelby Co., Ky.Shelby Co., Ky.
• Circular, fault-bounded structural and topographic high
• About 2.5 miles in diameter, central uplift core, with flank area of annular and radial faults
• Cryptoexplosive structure or meteor impact?
• Ordovician limestones extensively dolomitzed
Jeptha Knob coresJeptha Knob cores
• Cored for mineral exploration• 3 continuous cores, from surface to about
2,000 ft• Breccias and dolomite with high-angle dips;
high porosity and permeability in dolomitized Trenton
• Hydrothermal? – no saddle dolomite observed
OC
OL OH
OcfOcfOC
OLOH
StructurallyComplex
JK 78-1
JK 78-3
JK 78-2
SilurianRocks
UndeformedLower Part
No Vertical Exaggeration
A A'South North
0
200
400meters
0
200
400meters
L
Jeptha Knob Cross SectionM. Pope (in prep.)
JK78-1,341 ft
• High angle dips, chaotic bedding, and breccias
• Skeletal grainstones and packstones (Trenton lithologies) dolomitized
• Abundant moldic and intercrystalline porostiy
ConclusionsConclusions
• Fault-related, hydrothermal dolomites occur in Trenton–Black River outcrops in Kentucky
• Good laboratory to develop models for hydrothermal dolomitization that will be applicable throughout the basin