GAS & OIL FIELDS WITH MANCOS RESERVOIRS

The Uinta Basin is located in northeastern Utah, bounded by the Uinta Mountains to the north, which are a Late Creta-ceous to early Tertiary Laramide uplift. The basin narrows and shallows to the west, and the ba-sin fill gradually thins against the Wasatch Range where older Me-sozoic and Paleozoic rocks crop out. The southern margin is the Book Cliffs where the Mancos crops out. The eastern margin is the Douglas Creek arch which separates the Uinta from the Piceance Basin in Colorado.

The DOGM has identified about three dozen oil and gas fields with Mancos production or po-tential Mancos reservoir. How-ever a number of these fields are inactive, and in the majority of the active fields, Mancos produc-tion is comingled with produc-tion from lower reservoirs, com-monly in the Dakota Sandstone, or overlying Cretaceous and Ter-tiary reservoirs, making it diffi-

cult to assess the Man-cos productivity. Only the Atchee Ridge and Black Horse Canyon fields produce exclu-sively from the Mancos.

Subsurface correlation and structure of the Mancos Shale, Uinta Basin, Utah

INTRODUCTIONThe University of Utah and the Utah Geological Survey (UGS) are starting the final year of a three-year, multidisciplinary study of the Upper Cretaceous Mancos Shale in the Uinta Basin of eastern Utah. The goals of this project are to provide the industry with an assess-ment of the natural gas potential of the Mancos and to define the most prospective zones within this 4000-foot-thick stratigraphic unit. The poster panels here represent the current status of the subsurface cor-relation component of the project.

The objective of the correlations is to construct a stratigraphic model in which to incorporate data and interpretations generated by other activities within the project. Specifically these include geochemistry, maturation modeling, petrophysical characterization, facies analysis, and seismic attribute determination. Our goal is to assign these geo-logic properties to specific stratigraphic units in order that these prop-erties could be traced into parts of the basin where such data are scarce or expensive to acquire.

For additional information about the UGS/University of Utah Mancos Shale project, please visit the UGS exhibit booth or the project website at: http://geology.utah.gov/emp/shalegas/cret_shalegas/index.htm

Andrew D. McCauley1, Brendan K. Horton1, Robert Ressetar2, and Lauren P. Birgenheier1

1DepartmentofGeology&Geophysics,UniversityofUtah,SaltLakeCity,UT 2UtahGeologicalSurvey,SaltLakeCity,UT

METHODSThe data for the subsurface correlations come from more than 150 well records in UGS and Utah Division of Oil, Gas, and Mining (DOGM) files, supplemented with data donated by our industry partners. We downloaded tops of stratigraphic units into IHS Petra software. Most of the tops from IHS were taken from the well completion reports filed with the DOGM, and we used these for the initial correlations. We tied our correlations to published stratigraphic sec-tions, mostly around the basin perimeter. Specific publications that proved useful by discussing log characteristics and/or provid-ing insights into continuity of stratigraphic units were those by Molenaar and Wilson, 1990; Molenaar and Cobban,1991; John-son, 2003; Anderson and Harris, 2006; McPherson and others, 2006; Hampson, 2010; and Anna, 2012.

ResearchPartnership to Secure Energyfor America

THE UNIVERSITY OF UTAH

Department ofGeology & Geophysics

THE UNIVERSITY OF UTAH

Department ofChemical Engineering

STRATIGRAPHIC FRAMEWORK

Cedar Mountain Fomration

Tununk Member

Cedar Mountain Formation

Questar 1 &

Questar 8

Questar 16

RGU-1

Dakota Sandstone

Tununk Member

Cedar Mountain Formation

Pioneer 1Pioneer 2

RED WASH

WONSITSVALLEY WHITE

RIVER

NATURALBUTTES

MONUMENTBUTTE PARIETTE

BENCHBONANZA

UTELANDBUTTE HELL'S

HOLE

HILLCREEK

CASTLEGATE

PETER'SPOINT

DRY BURN

PINESPRINGS

SWEETWATERCANYONGORDON

CREEK

MAINCANYON

FLAT ROCKWOLFPOINTMILLER

CREEK BLACK HORSECANYON

BRYSONCANYONWESTWATER

BUSHYFIELDMANCOS

FLAT

GREATERCISCO

HELPER

AGENCYDRAW

UNNAMED26-4S-1E

ATCHEERIDGE

LONESPRING

SOUTHCANYON

SWEETWATERRIDGE

WHISKEYCREEK

GATECANYON

PRICE

DUCHESNE

RAT HOLE CANYON

HORSESHOE BEND

U i n t a B a s i n

B o o k Cl

if

fs

UTAHGREENRIVER

0 10 205 Miles $

An east-west chro-nostratigraphic section of the Mancos and adja-cent units shows these relationships:

The Mancos represents up to 15 million years of deposition. The Late Cre-taceous Sevier orogen to the west shed clastics to the foreland basin in the east. Clastics became pro-gressively finer-grained to the east and interfin-gered with deltaic and marginal marine sands (Ferron, Emery, and Blackhawk Formations), which in turn graded into the units of the Man-cos Shale. The relatively coarser-grained, siltier to sandy members of the Mancos such as the Juana Lopez and Prairie Canyon (or Mancos B) probably represent shifts in the balance between relative sea level and sed-iment supply.

Four stratigraphic inter-vals are potential targets as shale-gas reservoirs: the Prairie Canyon, the Lower Blue Gate, the Juana Lopez, and the Tu-nunk. Approximate well locations are represented by black stars.

CROSS SECTION EXPLANATION

Wells in the cross sec-tions are identified by (from top down): a one- to three-digit well sequence num-ber assigned by the software, API num-ber, and well name. The datum for all sec-tions is the top of the Castlegate Sandstone. Diagonal patterns in wells 6, 181, and 208 show locations of cores studied by Ken-nedy (2011) and Hor-ton and others (2012).

DuchesneWasatch

Utah

Carbon

Emery

Grand

Uintah

Red & blue lines show regional cross sections.Green line shows detailed cross section.

Limit of preserved post-Mancos strata

3

56

16

70

73

137

161168

181

198

208

211

223

239

246

253254

256273285

327

329

332333

336

365372

389

454

457

466

468

476

493

498503

0 10 20 40 miles

EAST-WEST SECTION

Emery

Lower Blue Gate

Present land surface

Dakota

Ferron

Tununk

Emery

Datum:

Top of Castlegate

Aberdeen

Spring Canyon

Kenilworth

Sunnyside

Mancos

Mancos B

Lower Blue Gate

Juana Lopez

Coon Spring

Tununk

Upper Blue Gate

5

STATE 18-1A

47643007100260000

ABBOTT 1

643007301290000STATE OF UTAH RGU1

25343007300240000

PEASE 3

45443007300270000COAL CREEK 1

50343007202530000

IRIART 1

343007107530000KEEL RANCH 1

1643013334370000

RYE PATCH FED 22-21

45743007202860000

STONE CABIN UNIT 1

49843007312780000

PETERS PT 14-27D-12-16

25443007308590000PETERS PT 6-7D-13-17

49343047369310000UTE 1-20-1319

39843047334470000

DEL-RIO/ORION CR 32-13

36543047309600000

22 PINE SPRINGS 15-16-14

20843047377050000

MAIN CYN FEDERAL 23-7-15S-23E

73

5

476

6

253

454

503

3

16

894754254

493

398365

208

73

20 200GR [GAPI]

20 200GR [GAPI]

-10 240SN [ohm.m]

20 200GR [GAPI]

20 200GR [GAPI]

-1 10SP [MV]

30 130CILD [S/m]

20 200GR [GAPI]

-10 240SN [ohm.m]

20 200GR [GAPI]

-10 240SN [ohm.m]

20 200GR [GAPI]

-200 1000LLS [OHMM]

20 200GR [GAPI]

20 170GR_NRM

-60 100R85F [OHMM]

20 200GR [GAPI]

-320 480AT90 [OHMM]

20 200GR [GAPI]

0 200HDRS [OHMM]

20 200GR [GAPI]

-50 200ILD [OHMM]

-20 220GRD [ohm.m]

-50 200ILD [OHMM]

20 200GR [GAPI]

-150 150RLA4 [OHMM]

20 200GR [GAPI]

-50 200ILD [OHMM]

1000

200 0

100 0

200 0

300 0

400 0

100 0

100 0

200 0

300 0

400 0

500 0

100 0

200 0

300 0

400 0

300 0

700 0

800 0

900 0

100 0

011

0 00

120 0

0

100 0

011

0 00

120 0

013

0 00

140 0

015

0 00

160 0

0

800 0

900 0

100 0

011

0 00

120 0

013

0 00

140 0

0

900 0

100 0

011

0 00

120 0

013

0 00

140 0

015

0 00

900 0

100 0

011

0 00

120 0

013

0 00

140 0

015

0 00

800 0

900 0

100 0

011

0 00

120 0

013

0 00

700 0

800 0

900 0

100 0

011

0 00

600 0

700 0

800 0

900 0

500 0

600 0

700 0

800 0

900 0

100 0

0

500 0

600 0

700 0

800 0

Emery

Lower Blue Gate

Present land surface

Dakota

Ferron

Tununk

Emery

Datum:

Top of Castlegate

Aberdeen

Spring Canyon

Kenilworth

Sunnyside

Mancos

Mancos B

Lower Blue Gate

Juana Lopez

Coon Spring

Tununk

Upper Blue Gate

Emery

Lower Blue Gate

Present land surface

Dakota & older

Ferron

Tununk

Emery

Datum:

Top of Castlegate

Aberdeen

Spring Canyon

Kenilworth

Sunnyside

Mancos

Blackhawk

Mancos B

Lower Blue Gate

Juana Lopez

Coon Spring

Tununk

Upper Blue Gate

43007300780000 43047302480000BLACK HORSE CYN 2

0 5 10 20 miles0 ft

500

1000

info

rmal

Low

er B

lue

Gat

e m

arke

rs

EASTWEST

The western end of the section is located south of the Book Cliffs, near the northern end of the San Rafael Swell. The Coon Spring Sandstone can be traced with reasonable confidence from the eastern end of the section to near well #16, but control is lacking for correlation farther west. As in the north-south sec-tion, the four informal lower Blue Gate markers can be correlated across a large area of the basin. The interfingering of the deltaic units of the Spring Canyon through Sunnyside sandstones is based on work by Hampson (2010). Although the Mancos in the eastern part of the cross section represents a greater range of time than does the Mancos to the west, it is considerably thinner.

DETAILED CROSS SECTIONStephanie Carney and Jeremy Gleason of the UGS assisted with, respectively, assembling the Petra database and with graphic design.

Funding for this project is provided by RPSEA through the “Ultra-Deepwater and Unconventional Natural Gas and Other Petroleum Resources” program authorized by the U.S. Energy Policy Act of 2005. RPSEA (www.rpsea.org) is a nonprofit corporation whose mission is to provide a stewardship role in ensuring the focused research, development

and deployment of safe and environmentally responsible technology that can effectively deliver hydrocarbons from domestic resources to the citizens of the United States. RPSEA, operating as a consortium of premier U.S. energy research universities, industry, and independent research organizations, manages the program under a contract with the U.S. Department of Energy’s National Energy Technology Laboratory.

Acknowledgments

Anna, L.O., 2012, West-east lithostratigraphic cross section of Cretaceous rocks from central Utah to western Kansas: U.S. Geological Survey Open-File Report 2012–1074, 2 sheets.

Anderson, D.S., and Harris, N.B., 2006, Integrated sequence stratigraphic and geochemical resource characterization of the lower Mancos Shale, Uinta Basin, Utah: Utah Geological Survey Open-File Report 483, compact disk.

Dubiel, R.F., 2003, Geology, depositional models, and oil and gas assessment of the Green River total petroleum system, Uin-ta-Piceance Province, eastern Utah and western Colorado, in USGS Uinta-Piceance Assessment Team, Petroleum sys-tems and geologic assessment of oil and gas in the Uinta-Piceance Province, Utah and Colorado: U.S. Geological Sur-vey Digital Data Series DDS–69–B, compact disk.

Hampson, G.J., 2010, Sediment dispersal and quantitative strati-graphic architecture across an ancient shelf: Sedimentology, v. 57, p. 96-141.

Hampson, G.J., Howell, J.A., and Flint, S.S., 1999, A sedimen-tological and sequence stratigraphic reinterpretation of the Upper Cretaceous Prairie Canyon Member and associated strata, Book Cliffs area, Utah, USA: Journal of Sedimentary Research, v. 69, p. 414-433.

Horton, B.K., Birgenheier, L.P., Johnson, C., Rowe, H, Kennedy, A., and McLennan, J., 2012, Litho- and chemofacies vari-ability in a siliciclastically dominated shale/mudstone sys-tem—heterogeneities of the developing Mancos Shale gas play [abs.]: American Association of Petroleum Geologists Annual Conference & Exhibition Abstracts Volume, com-pact disk.

Johnson, R.C., 2003, Northwest to southeast cross section of Cre-taceous and lower Tertiary rocks across the eastern part of the Uinta Basin, Utah, in USGS Uinta-Piceance Assessment Team, compilers, Petroleum systems and geologic assess-ment of oil and gas in the Uinta-Piceance Province, Utah and Colorado: U.S. Geological Survey Digital Data Series DDS–69–B, compact disk.

Johnson, R.C., and Roberts, S.B., 2003, The Mesaverde total pe-troleum system, Uinta-Piceance Province, Utah and Colora-do, in USGS Uinta-Piceance Assessment Team, Petroleum systems and geologic assessment of oil and gas in the Uinta-Piceance Province, Utah and Colorado: U.S. Geological Sur-vey Digital Data Series DDS–69–B, compact disk.

Kennedy, A.D., 2011, Geologic predictors of the hydrocarbon ex-traction potential of the Mancos Shale: Salt Lake City, Uni-versity of Utah, M.S. thesis.

Kirschbaum, M.A., 2003, Geologic assessment of undiscovered oil and gas resources of the Mancos/Mowry total petro-leum system, Uinta Piceance Province, Utah and Colorado, in USGS Uinta-Piceance Assessment Team, Petroleum sys-tems and geologic assessment of oil and gas in the Uinta-Piceance Province, Utah and Colorado: U.S. Geological Sur-vey Digital Data Series DDS–69–B, compact disk.

McPherson, M.L., Currie, B.S., and Pierson, J.S., 2006, Reser-voir characterization of the Cretaceous Cedar Mountain and Dakota Formations, southern Uinta Basin—year-one report: Utah Geological Survey Open-File Report 492, 20 p.

Molenaar, C.M., and Cobban, W.A., 1991, Middle Cretaceous stratigraphy on the south and east sides of the Uinta Basin, northeastern Utah and northwestern Colorado: U.S. Geo-logical Survey Bulletin 1787-P, 34 p.

Molenaar, C.M., and Wilson, B.W., 1990, The Frontier Formation and associated rocks of northeastern Utah and northwest-ern Colorado: U.S. Geological Survey Bulletin 1787-M, 21 p.

Young, R.G., 1955, Sedimentary facies and intertonguing in the Upper Cretaceous of the Book Cliffs, Utah-Colorado: Geo-logical Society of America Bulletin, v. 66, p. 177-202.

References

43047398090000246FR

43047351400000168

HILL CREEK NORTH

43047349220000161

HILL CREEK NORTH

43047303550000333

WOLF POINT UNIT

43047377050000208

MAIN CANYON FEDERAL

43047302470000329

BLACK HORSE CANYON

0 150GR

0 24RT

0 150GR

2 2000HDRS

0.3 -0.1NPHI

0 150GR

2 3RHOZ

0.3 -0.1NPHI

0 150GR

2 2000RILD

0 150GR

2 2000RXO8

2 3RHOZ

0.3 -0.1NPHI

0 150GR

2 2000ILD

0.3 -0.1PHI

604CSLG [3]CSLG_T [ADM]

MNCS_T [ADM]

UBL_Q [ADM]UBL_E [ADM]

UBL_R [ADM]

UBL_T [ADM]UBL_Y [ADM]

603MNCSB [3]MNCS_B_T [ADM]MCB_W [ADM]MCB_T [ADM]MCB_Y [ADM]

MCB_E [ADM]

MCB_S [ADM]MCB_A [ADM] MCB_I [ADM]MCB_Q [ADM]MCB_U [ADM]

LBLGT_T [ADM] LBLGT

MFS_S [ADM]

MFS_A [ADM]

MFS_G [ADM]MFS_H [ADM]

MFS_J [ADM]

MFS_F [ADM]MFS_D [ADM]MFS_I [ADM]

MFS_O [ADM]

MFS_P [ADM]

MFS_U [ADM]

MFS_Y [ADM] MFS_E [ADM]

MFS_R [ADM]

MFS_T [ADM]

MFS_K [ADM] MFS_W [ADM]

MFS_Q [ADM]

603JLPZ [3]

JLPZ_T [ADM]

603TNNK [3]COON_SPRG

DKSL_T [ADM]

MCB_O [ADM]

UBL_W [ADM]

6600

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6800

6900

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RelDepth(ft)

RelDepth(ft)

-200 -200-100 -100

0 0100 100200 200300 300400 400500 500600 600700 700800 800900 900

1000 10001100 11001200 12001300 13001400 14001500 15001600 16001700 17001800 18001900 19002000 20002100 21002200 22002300 23002400 24002500 25002600 26002700 27002800 28002900 29003000 30003100 31003200 32003300 33003400 34003500 35003600 36003700 37003800 38003900 39004000 40004100 41004200 42004300 43004400 44004500 45004600 46004700 47004800 48004900 49005000 5000

Mancos Shale, Fall 2012 ADM

201050 miles

Working with closely spaced logs makes it possible to correlate a large number of surfaces within the Mancos Shale. The closely spaced correlations are made on gamma-ray spikes provisionally interpreted as flooding surfaces in the lower Blue Gate (prefixed MFS), the Mancos B (MCB), and upper Blue Gate (UBL). This east-west section in the southeastern basin shows the overall eastward thinning of the Mancos, in large part due to the lateral transition of a number of coarsening-up packages in the Lower Blue Gate Member in the West into bow patterns in the East. Otherwise the Blue Gate Member is characterized by layer-cake geometries, while the Mancos B (Prairie Canyon) member shows a more complicated internal stratigraphy.

NORTH-SOUTH SECTION

Blackhawk

Upper Blue Gate

Mancos B

Lower Blue Gate

Juana Lopez

Mowry

Tununk

Coon Spring/Lower Tununk

Lower Tununk

Frontier

Dakota

DakotaCoon Spring

27343019301690000

STATE 428-1

28543019306530000

CHERRY CANYON UNIT 16-1

25643019108040000

CHERRY CANYON UNIT 1

32743047161980000

FENCE CANYON UNIT 2

37243047310420000

PINE SPRINGS 7-21-14-22

3654304730960000022 PINE SPRINGS 15-16-14

33243047301350000

SEEP RIDGE UNIT 2

32943047301150000

TEXACO-CHORNEY B NCT-1

7043047301650000TEXACO-SKYLINE-GOVT 1

46843047303570000BUCK CAMP 1

33643047302260000

GRAYKNOLLS-FEDERAL 1

19843047374440000

HILL CREEK UNIT 15-33F

23943047396110000

HCU 12-29F

13743047341370000ISLAND UNIT 86

46643047301110000

CONOCO-FEDERAL 22-1

18143047362600000

GLEN BENCH 16M-28-8-21

21143047380490000

WONSITS VALLEY 11AML-14-8-21

22343047389950000

TU 3-35-7-21

273 285

256

327

372

365

332

329

70

468

336

198

239

137

466

181

211

223

>MK69.3<>MK86.2< <5.55KM> <12.06KM> >MK47.3<>MK92.2< <4.88KM> <2.95KM> <7.16KM> <9.92KM> <18.12KM> <3.13KM> <7.07KM> <9.12KM> <12.16KM> <4.61KM> <5.46KM>

20 200GR

-10 40ILD

20 200GR

0 70RILD

20 200GR

-10 40ILD

20 200GR

-10 40ILD

-20 220GRD

-10 40ILD

-20 220GRD

-10 40ILD

20 200GR

-10 40ILD

20 120GRS

-10 40ILD

20 200GR

-10 40ILD

20 200GR

-190 260LL8

20 200GR

-2 70LLD

20 200GR

-10 40RXOZ

20 200GR

20 200GR

20 200GR

-190 260LL8

20 200GR

-10 40RXOZ

20 200GR

20 200GR

6000

7000

8000

9000

6000

7000

8000

9000

6000

7000

8000

9000

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6000

7000

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6000

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0

7000

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0

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8000

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011

000

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011

000

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0

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011

000

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013

000

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0

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011

000

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013

000

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0

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011

000

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013

000

1400

015

000

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012

000

1300

014

000

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0

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013

000

1400

015

000

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0

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013

000

1400

015

000

1600

0

1300

014

000

1500

016

000

1700

018

000

Blackhawk

Upper Blue Gate

Mancos B

Lower Blue Gate

Juana Lopez

Mowry

Tununk

Coon Spring/Lower Tununk

Lower Tununk

Frontier

Dakota

DakotaCoon Spring

Datum:Top of Castlegate

Blackhawk

Upper Blue Gate

Mancos B

Lower Blue Gate

Juana Lopez

Mowry

Tununk

Coon Spring/Lower Tununk

Lower Tununk

Frontier

Dakota

Dakota & olderCoon Spring

SOUTH NORTH

0 5 10 20 miles

0 ft

500

1000

In the southern part of this section, the base of the Mancos appears as positive gamma ray deflection above the Dakota Formation. Shortly above this is a coars-ening up (parasequence?) that Molenaar and Cobban (1991) named the Coon Spring Sandstone Bed of the Tununk Member, and which they correlated with the “Dakota silt” of drillers’ logs. As they pointed out however, this unit is not ge-netically related to the Dakota Formation. And to the north the Coon Spring can’t be identified. In some wells the base of the Juana Lopez can be recognized by a subtle gamma ray deflection and by a resistivity increase, but not everywhere.

Farther north the Mowry Shale appears between the Dakota Formation and the Mancos. Molenaar and Cobban (1991) showed the Mowry-Dakota contact as a fa-cies change. But the log pattern here suggests the Dakota coarsens upward and is abruptly overlain by the Mowry at a flooding surface. Along the basin’s north-

ern margin the Tununk and the Juana Lopez grade into the Frontier Formation, a sandy unit derived from a river system to the west. In outcrops north of Vernal, Utah, the Frontier can be seen directly overlying the Mowry. Note, however, that the upper Frontier is a coarsening up parasequence capped by a flooding surface and has a log pattern very similar to the Coon Spring. In fact, well completion re-ports identify this as the “Dakota silt,” although it’s several million years younger and stratigraphically higher than the Dakota silt/Coon Spring to the south.

Four prominent gamma-ray deflections have been informally identified in the lower Blue Gate, but have not yet been genetically interpreted. They demonstrate, however, that stratigraphic subdivision of the thick shale members of the Mancos is a reasonable goal.