blackfeet reservation list of topics - …...the cut bank field, which extends from townships 31 to...

BLACKFEET RESERVATION ?List of Topics

BACKGROUND

� Overview of Reservation

� Production Overview

GEOLOGIC OVERVIEW

� Geologic History

� Summary of Play Types

CONVENTIONAL PLAY TYPES

� Play 1 - Fracture/Folded Anticline Mississippian Carbonate

� Play 2 - Jurassic/Cretaceous Sandstone Play

� Play 3 - Devonian/Mississippian Carbonate Play

� Play 4 - Montana Disturbed Belt - Imbricate Thrust

UNCONVENTIONAL / HYPOTHETICAL PLAY TYPES

� Play Types 5,6,7 - Bakken, Cambrian Sandstone, and Biogenic Gas Plays

REFERENCES

Blackfeet Reservation

OVERVIEW

BLACKFEET INDIAN RESERVATION Blackfeet Nation

TRIBAL HEADQUARTERS:� Browning, Montana GEOLOGIC SETTING:� � Southern Alberta Basin

General Setting � most of Glacier County. Alberta. The Badger

southwest.

Chief Mountain on the northwest boundary. �

the Reservation.

to the north.

Mineral Ownership and Leasing �

owners. �

This

joint venture agreements.

Seismic Data � brokerage firms.

today. the BIA or the Blackfeet Tribe. �

Contact:

� � Gary MadMan � � Director, Minerals Department � � Blackfeet Nation � � P.O. Box 639 � � Browning, MT 59417 � � � TEL: (406) 338-5020

Petroleum Exploration and Development �

Glacier National Park (Darrow, 1955).

Glaciers Lodge (Douma, 1953). This early

production came from a depth of 500'. six of which produced oil (Darrow, 1955).

of the petroleum industry in Montana. �

1929 (Chickering, 1958; Del Monte, 1958).

�

initiated. The Montana Oil and

Bank Field. being idle.

So far,

sand and the Madison Formation. �

Butte, and Reagan. and Blackfoot East.

Annual Review). secondary waterfloods. from these fields for 1992 was approximately 815,000 mcf. � Reservation boundaries during the past ten years.

Airport Unit.

recovered.

Geology � Basin.

and the Sweetgrass Arch on the east.

Of these

amount of exploration. �

The large scale

rocks to create a reservoir. Range in Alaska southward to Central America.

Reservation near East Glacier.

Other

of the Devonian. �

on the east to 14,000' on the west.

� production.

�

of the Sweetgrass Arch. result of a stratigraphic trap in the Kootenai Formation.

Of

limited exploration.

adequately tested.

83

287

89

2

15

89

2

87

15

93

Eureka

West Glacier

Whitefish

Kalispell Conrad

Choteau

Bowmans Corner

East Glacier Park

Ravalli Superior

Shelby

Ft. Benton

Great Falls

Wolf Creek

Browning

Pelson

Glacier

Flathead Pondera

Teton

Lewis and ClarkMissoula

Cascade

Toole

Liberty

FLATHEAD

BLACKFEET

CANADA MONTANA

�OVERVIEW index map topics

Montana

The Blackfeet Reservation is located in northwestern Montana and includes On the north it borders the Canadian Province of

On the west it shares a border with Glacier National Park. Two Medicine portion of the Lewis and Clark National Forest borders on the

Other natural boundaries include Birch and Cut Bank Creeks. Elevations vary from a low of 3400' in the southeast to a high of over 9000' at

Major railroads and highways serving the Reservation include Burlington Northern Railroad’s main east/west line. This is paralleled by U.S. Highway #2, and is bisected by U.S. Highway #89 at Browning, the administrative center for

Great Falls, Montana, an air traffic center, is approximately 125 miles to the southeast, and Calgary, Alberta, Canada is approximately 210 miles

The Blackfeet Reservation contains 1,525,712 acres, with the mineral estates divided as follows. Approximately 41.8% of the minerals is tribally owned. Another 31.3% is owned by allottees, and the remaining 26.9% is owned by fee

A Mineral Assessment Program is currently operating under a three-year plan to evaluate and further define the oil and gas potential of the Reservation. program also assists the Tribe in the evaluation of new leasing, operating and

New leases, other mineral exploration, and development agreements are designed in accordance with the 1982 Indian Mineral Development Act, and the rules and regulations contained in 25 CFR. Companies are welcome to negotiate with the Blackfeet Tribal Business Council for any type of lease or joint venture agreement which will satisfy both parties.

Seismic data from past seismic surveys are available from several seismic The Tribe has purchased seismic data for some portions of the

Reservation and are in the process of reprocessing the data using technology of Information on conducting new seismic operations can be obtained from

Most of the leases and other types of agreements currently in effect on the Reservation are in areas now under production. This leaves a large portion of the Reservation’s minerals available for leasing.

The first commercial oil discovery in Montana was made in the spring of 1903 in the Swift Current Valley, just west of the Reservation in what is now

This discovery was made by a prospector named Sand D. Somes who was looking for copper ore in the Swift Current Valley, now covered by the water of present day Sherburne Lake near Many

His interest in oil developed in 1902 when he found pools of oil when cleaning out his workings after blasting.

By 1906, twelve wells had been drilled, The best oil well, completed during

the spring of 1906, had an initial production of 60 barrels of oil per day. Although production from this oil field was short lived, it marked the beginning

Just off the Reservation’s eastern edge, along the west flank of the Sweetgrass Arch, random drilling led to the discovery of gas in 1926 and of oil in

By the early 1930’s, development drilling had extended the known limits of this field onto the reservation.

The Cut Bank Field, which extends from Townships 31 to 36 North, in Ranges 5 and 6 West, produced 164,499,336 barrels of oil through December 1992 (Montana Oil and Gas Conservation Division, 1993), with annual production of oil still over 740,000 barrels, and nearly 3 million cubic feet of gas. Approximately 25 percent of the Cut Bank Field area lies within the Reservation. When production began to decline in the mid 1940’s due to the pressure decline of the solution gas drive (Chickering, 1958), secondary recovery operations were

The secondary recovery methods used were chiefly waterfloods, which resulted in an increase of production by the early 1950’s. Gas Annual Review for 1992 lists 11 secondary recovery projects in the Cut

All of these are listed as waterfloods, with six of them listed as Oil and/or gas production is found in the following formations within

the Cut Bank field area: Blackleaf, Bow Island, Dakota, Kootenai (Moulton, Lander, Sunburst, and Cut Bank sands), and the Madison Group. secondary recovery operations have been limited to the Cut Bank sands, Lander

Other oil and/or gas fields on or near the Reservation include Big Rock, Blackfoot Shallow Gas, Bradley, Little Rock, Blackfoot, East Glacier, Landslide

Inactive or abandoned fields include Two Medicine Creek, Cumulative production from these fields through 1992 is

11,381,868 barrels of oil (Montana Oil and Gas Conservation Division, 1992 Two of these fields, Blackfoot and Reagan, have active

Annual gas production plus associated gas produced

Only limited exploration and development drilling has taken place within the The most recent drilling

activity involves the use of horizontally drilled wells, by Unocal, in the Cut Bank The use of horizontal wells in conjunction with secondary recovery

methods should result in a higher percentage of the original oil in place being

The Blackfeet Indian Reservation occupies a portion of the southern Alberta Tectonically, the area can be divided into three provinces: the

Disturbed/Overthrust Belt on the west, the Foreland Basin in the central portion, The stratigraphy of the Reservation is

generally characterized by the clastic section of the Cretaceous-Jurassic and the carbonates of the Mississippian-Devonian. On the Reservation, production exists in formations within the Cretaceous, Jurassic, and the Mississippian.

three provinces, only the Sweetgrass Arch has received more than a very limited

The Disturbed/Overthrust Belt is a zone of northerly, closely-spaced, subparallel thrust faults and folds with some known normal faults. structural dislocation of these sub-parallel thrust faults may result in older reservoir rocks overlying younger source rocks, or in the fracturing of source

This geologic province extends from the Brooks In Alberta, Canada this belt

contains a number of large fields including Pincher Creek and Waterton Lakes. There is limited production of oil and gas from the Disturbed Belt portion of the

The primary reservoir rocks in this region would be the Mississippian carbonates - limestones and dolomites - which are productive to the south of the Reservation at the Blackleaf Canyon Field. potential reservoirs would include the sands of the Cretaceous and the carbonates

The Foreland Basin is represented by a relatively undeformed wedge of Mesozoic and Paleozoic rocks that vary in thickness from approximately 5,000'

Although the Cretaceous, Jurassic, and the Mississippian portions of the geological section have a high potential for oil and gas production, the Devonian should also be considered as having significant undiscovered hydrocarbon potential. It is this Foreland Basin broad shelf that, during the Devonian, was the site of the deposition of reef-type rocks and sediments that have shown production to the north in the Alberta Basin. Production from the Devonian section also occurs in the Kevin-Sunburst area of the Sweetgrass Arch. Although highly productive of oil and gas in Canada, exploration for the Devonian on the Reservation has been insignificant.

The Sweetgrass Arch portion of the Reservation contains most of the existing This production occurs in the clastic sediments of the Cretaceous

and Jurassic sections, and in the carbonates of the Mississippian. In contrast to the structurally complex Disturbed/Overthrust Belt, the

Sweetgrass Arch structure is controlled by the generally westward dipping flank The largest producing field, the Cut Bank Field, is the

Some localized structural irregularities occurred along the west flank of the Sweetgrass Arch. Reagan Field is developed on one of these localized structural irregularities. the three geological provinces, only the Sweetgrass Arch has received more than

However, even in this highly productive area of the Sweetgrass Arch the full potential of the geologic section has not been

Belt

Disturbed

G L A C I E R

N A T I O N A L

P A R K

Explanation

Oil or Gas from Cretaceous Kootenai

Oil or Gas from Madison

Reservation Boundary

Structure on Top of Colorado Shale

Thrust Fault

Normal Fault

High angle Reverse Fault

Syncline

Anticline

UD

Oil and Gas from Cretaceous Greenhorn

Blackleaf

Canyon

Reagan Darling Border/Red Coulee

Cutbank

Kevin-Sunburst

Gypsy Basin Highview

Blackfoot Field

D U

1750

Sharp

Folds U

nderlain by

Thrust

Faults

Lewis

Overthrust

Fault

Approxim

ate

Limit

East

of

Surface

G L A C I E R

P O N D E R

A L B E R T A

37

36

35

34

10 911

33

30

29

31

D I S T U

R B

E D

8

1000

2000

2250

1250

1500

0 250 500

1000

750

2000

2500

2250

Pondera

Teton County

North

OVERTHRUST

FAULT

Two Medicine

East Glacier

Browning

7 6 5

-250

-500

-750

-1000

GENERAL PRODUCTION INFORMATION

U.S.G.S Geologic Province: � North Central Montana

Tectonic Province: � � Sweetgrass Arch, Foreland Basin, � � � � � Montana Disturbed Belt

Overall Production:� � 440 MMBO and 1.1 TCFG from U.S.G.S. Play Production Province

� � � No. of Fields: � 170 discovered fields � � � � � 58 greater than 1 MMBO or 6 BCFG

� 1941 Reagan� � � � 9.3 MMBO, 15 MMcfd, 54 wells � 1955 Two Medicine� � � 9.3 MMBO, 15 MMcf, 54 wells � 1926, 1929 Cutbank � � � 167.3 MMBO, 317 MMcf � � (est. 20% within boundary)� � 447 wells oil, 235 wells gas

EARLY EXPLORATION ON THE BLACKFEET RESERVATION

� Oil and gas was discovered in Montana in the late 19th century as oil seeps, in what is now Glacier National Park. The

achieved a depth of 1450 feet in 1902. "sand unit" at a depth of 720 feet. � production in 1902.

mining operations. With the establishment of Glacier National Park in 1910, oil exploration was suspended. �

1920's. which is one of the largest in the Rocky Mountains. Twenty

� Mississippian Madison with Pondera Field. Other discoveries throughout the 1930's and 40's led to both Cretaceous and Madison production. Montana disturbed belt which led to the discoveries of East Glacier/Two Medicine and Blackleaf Canyon.

MMcfd.

Figure BF-2.1.

PRODUCING HORIZON LEGEND

Fort Union

Fox Hills

Judith River

Eagle

Niobrara

Greenhorn

Dakota Group

Morrison

Ellis Group

Swift Reirdon Piper

Nesson

Spearfish

Minnekahta

Opeche

Minnelusa

Amsden

Tyler

Heath Otter Kibbey

Madison GroupCharles

Lodgepole

Bakken Three Forks Nisku Duperow Souris River Dawson Bay Winnipegosis

Interlake

Stonewall

Stony Mountain

Red River

Winnipeg

Deadwood

Mowry

Muddy

Dakota

Fall River

Lakota

Morrison

Sundance

Canyon Springs

Gypsum Spring

Chugwater

Spearfish

Goose Egg

Minnelusa

Madison

Englewood

Jefferson

Interlake

Big Horn

Lance Fox Hills Mesaverde Cody Shannon Niobrara Frontier

Mowry Muddy Bear River Dakota Cloverly

Nugget Chugwater Ankareh Thaynes Woodside

Dinwoody

Phosphoria

Park City

Weber

Tensleep

Amsden Darwin

Jefferson

Darby

Madison

Mission Canyon

Lodgepole

Big Horn

Gallatin Gros Ventre Flathead

Fort Union

Blackleaf Bow Island

Kootenai Cat Creek Moulton Sunburst Cut Bank

Amsden

Tyler

Big Snowy Group Heath Otter Kibbey

Madison Group Sun River Charles Mission Canyon Lodgepole

Three Forks

Nisku Duperow

Souris River

Red River

Emerson

Flathead

Big Snowy Group

Mission Canyon

WESTERN WYOMING

SOUTHERN MONTANA

WESTERN & NORTHERN MONTANA

WILLISTON BASIN

POWDER RIVER BASIN

COLOR CODE

SE

RIE

S

SY

ST

EM

ER

A

TE

RT

IAR

Y

CE

NO

ZO

IC

CR

ET

AC

EO

US

UP

PE

RL

OW

ER

JUR

AS

SIC

TR

IAS

SIC

PE

RM

IAN

PE

NN

SY

LV

AN

IAN

MIS

SIS

SIP

PIA

ND

EV

ON

IAN

S

ILU

RIA

NO

RD

OV

ICIA

NC

AM

BR

IAN

M E

S O

Z O

I C

P

A

L

E

O

Z

O

I C

S

S

S

S

S = Source Rock

Gannet

Morrison

Sundance

Stump-Preuss

Twin Creek

Morrison Ellis Group

Swift Reirdon Sawtooth

Green River Wind River Wasatch Fort Union

White River

Wasatch

Fort Union

Lance Teckla Mesaverde Teapot Parkman Sussex Shannon Niobrara Frontier

Hell Creek Judith River Clagget Eagle Telegraph Creek Niobrara Greenhorn Frontier

Winnipeg

Deadwood

Figure BF-2.2. Producing Horizon Legend (after Geomap Executive Reference Map,1983).

NEARBY FIELDS 1956 Blackfoot - 1.6 MMBO, 3.0 MMcf, 8 wells oil, 7 wells gas 1958 Graben Coulee - 2.4 MMBO, 63 wells oil 1958 Red Creek - 6.5 MMBO, 1.2 MMcf, 18 wells oil 1954 Darling - 70,000 BO (Abn'd) 1929 Border - 497,000 BO, 346,000 Mcf, 1 well oil, 1 well gas 1929 OId Border - 798,450 BO, 7 wells oil 1954 Gypsy Basin - 504,783 BO, 3.1 MMcf, 4 wells total 1976 Highview - 101,477 BO, 741,600 Mcf, 7 wells total 1958, 1980 Blackfeet Canyon- 33,748 BO, 7.0 MMcf, (Abn'd) Other small fields with no current production

PLAY TYPES ENCOUNTERED Conventional � � 2) Jurassic-Cretaceous Sandstone Play (2808) � 3) Mississippian/Devonian Carbonate Play (2805) � 4) Montana Disturbed Belt-Imbricate Thrust Play (2701) Unconventional or Hypothetical � 5) Fractured Bakken (2804) � 6) Cambrian Sands (2802) � 7) Shallow Biogenic Gas (2810, 2811, 2812)

� �

Fields Within Reservation Boundaries - (1995 Cummulative Production)

first Montana well in this area was drilled in October of 1901, and Gas was flared from a

Swift Current Valley was the scene of the first commercial oil Early copper prospectors, among them Sand

D. Soomes, is credited with the discovery of oil seeps during By 1906, the field had six producing wells.

Early exploration on the Sweetgrass Arch, to the east of the reservation culminated in gas and oil discoveries in the late

January 1931, heralded the discovery of Cutbank Field,

percent of this "giant" field is within the reservation boundaries. Exploration during the late 1920's led to the discoveries in the

The 1950's saw a flurry of activity in the

In 1980, Williams Exploration and Milestone Petroleum tested the "A" Thrust Sheet at Blackleaf Canyon and discovered gas with rates as high as 5.1

General structure map of reservation and surrounding region.

1) Fractured/Folded Anticline Mississippian Carbonate Play (2807)

Blackfeet Reservation OVERVIEW index topicsmapMontana Oil & Gas Production PAGE 2 of 13

Montana

Introduction Regional Geologic Overview


Niobrara and Eagle

Jurassic Rocks

Mississippian Rocks

Niobrara and Eagle

Upper Cretaceous Rocks

Jurassic Rocks

Triassic Rocks

Permian RocksDevonian Rocks

Cambrian Rocks Sands and Shales

Prairie Salt

Devonian Rocks

Silurian Rocks

Mississippian Rocks

Pennsylvanian Rocks

Ordovician Rocks

Williston Basin


Bakken Shale

Tertiary Rocks Fort Union and Golden Valley

Poplar Dome

Little Rocky Mountains

Early Tertiary Intrusions

Upper Cretaceous Rocks

Bearpaw Uplift

Lower Cretaceous Kootenai

Overthrust Belt

Rocky Mountain Trench

Sweetgrass Arch

Lower Cretaceous Rocks Mowry

Nesson Anticline

- 6000

- 7000

- 8000

PreCambrian Rocks


0

- 1000

- 4000

- 5000

- 2000

- 3000

- 9000

- 10,000

- 11,000

- 12,000

- 13,000

114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 6000

5000

4000

3000

2000

1000

0

- 1000

- 2000

- 3000

- 8000

- 9000

- 10,000

- 11,000

- 12,000

- 13,000

- 4000

- 5000

- 6000

- 7000

Longitude Values (In Degrees) A'

EastWest

A

Ele

vati

on

(in

Fee

t)

Generalized X-Section A-A'

Present Day Structure

Line of Section along 48 degrees of latitude with selected points every 1 degree of longitude.

Datum : Sea Level Scale : 1 deg = about 50 miles


PRESENT DAY STRUCTURAL FEATURES

Rocky Mountain Region Precambrian Basement Uplifts

Other Uplifts or Basins

Cenozoic Volcanic Fields

Anticline

Syncline

Faults

Cross-Section

Bearpaw Uplift

Hogeland Basin

Little

Creek

Porcupine Dome

Crazy

Mountains

Basin

Bull Mountains

Basin

Poplar Dome

FP

BF

Yellowstone

Bighorn

Basin

Wind River

Basin Sweetwater

UpliftGreen

River

Basin Red

Desert

Basin

Hanna

Basin

Laramie

Mtns.

Laramie

Mtns

Black

Uplift

Sierra

Madre

Rock Springs Uplift

Uinta Mtns. Washake Basin

Snake River

Owl Creek

Mtns

Powder

River

Basin

MONTANA

IDAHO

UTAH

WYOMING

COLORADO

NEBRASKA

SOUTH DAKOTA

NORTH DAKOTA

EXPLANATION

A A'

Pryor Mtns.

114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 Alberta Shelf

Williston Basin

Lake Basin FaultNye-Bolwer Fault

BIGHO

RN MTN

Willow Creek Fault

Judith Mtns

Belt Mtns

Big Snowy Mtns

Beartooth Mtns

AbsarokaMtns

Alliance Basin

Har

tville

Medicine

Bow M

tns

Fault

Choctaw

Arch

Casper Mtn

Laramie Basin

Wind River M

tns

Casper

Arch

Hills

Miles City

Cedar C

reek

Weldon-Brockton Fault

Arch

Anticline

Poplar Fault

FORT BERTHOLD

Nes

son

Ant

iclin

e

STANDING ROCK

Hinsdale Fault

BowdoinDome

Little Rocky Mtns

WheatlandSyncline

BloodSyncline

Sw

eetgrass A

rch

Cat Creek Fault

Summatra

UNITED STATES

CANADA

OVER

THR

UST

BE

LT

Reservations

Regional Geology

predominatly sand and shale. Devonian in age and is mainly carbonates. composed of coarse-grained clastics. �

production is from Upper Cretaceous Greenhorn. from Jurassic age Swift and Sawtooth sands. Madison Sun River Dolomite and the Devonian Nisku.

Geologic History

The cross-The section

longitude intervals. � by high relief (greater than 5000 feet). section is about 11,000 feet thick.

geologic time. �

The

Reservations,

between Bowdoin Dome and Bearpaw Uplift. � looked like within that time interval. interval is shown; no rocks older than it are illustrated. The rock units above the

The datum is flat, representing the paleo ground surface.

Figure BF-3.1. Present day structural uplifts and basins, Fort Peck Reservation and location of regional cross-section A-A' (modified after Peterson 1987).

Figure BF-3.2. Generalized cross-section A-A', present day structure.

A A'

index map topicsPAGE 3 of 13

The Blackfeet Reservation lies within three distinct geologic provinces, the Montana Disturbed Belt to the west, the Foreland Basin in the center, and the Sweetgrass Arch to the east (see tectonic map and structure cross-section A-A'). The Mesozoic section, composed of Cretaceous and Jurassic rocks is

The Paleozoic section is Mississippian and The Cambrian section is mainly

Proven hydrocarbon production (see correlation chart and type log), is mainly from Lower Cretaceous Blackleaf and Kootenai sandstones, although some

Oil and gas is also produced Paleozoic production is from the

A generalized structural cross-section (see cross-section A-A', Figure BF-3.2) summarizes present day tectonic provinces and older paleostructure. section uses rock thickness values from each of the geologic periods. runs along the 48 degree latitude line and values were selected at one degree

The western end of the section, near the Blackfeet Reservation is dominated The Cretaceous and older Paleozoic

Major basement uplifts, such as the Sweetgrass Arch and Bearpaw Uplift, influenced sedimentation throughout

The eastern side of the cross-section is dominated by the Williston Basin, a stabel cratonic depocenter which has more than 15,000 feet of sediments. Fort Berthold Reservation is located near the depocenter and is within close proximity to Nesson Anticline, a major oil producing structure. Between these two tectonic provinces lie the Fort Peck and the Fort Belknap

Fort Peck is on the western flank of the Williston Basin and is dominated by Poplar Dome, a Laramide age structure, while Fort Belknap is

A paleo cross-section attempts to show what the subsurface geolgy may have For the sake of space, only the particular

interval have not yet been deposited; the top of the section is the datum.

Figure BF-4.2. Thickness of Deadwood and equivalent rocks. A-A' (modified after Peterson, 1987).

Cambrian Geologic History �

�

the Dakotas. Thickness of

thick at the eastern edge of the Williston Basin. � Reservations.

between Bowdoin Dome and the Bearpaw Uplift. �

shown. rocks, Ordovician to Triassic and Cretaceous to Jurassic.

shown. �

For the sake of space, on the particular interval is shown; no rocks older than it are illustrated. The rock units above the

The datum is flat, representing the paleo ground surface.

Williston Basin

PreCambrian Rocks

Poplar Dome


Bearpaw Uplift


Sweetgrass Arch

PreCambrian Rocks 2000

3000

4000

5000

6000

1000

0


Overthrust Belt

Thic

knes

s of

Sed

imen

t (fe

et)

Generalized X-Section A-A'

West A

114 113 112 111 110 109 108 107 106 105 104 103 102 101 100


Line of section along 48 degrees latitude with selected points every 1 degree of longitude.

Cambrian and Older Rocks

Datum: Base of Ordovician


Longitude Values (in degrees) A' East

Figure BF-4.1.

0

0

0

10

15

12

10

0

2

2 6

12 10 15

8

10

8

10

Cambrian and older rocks exposed at land surface

Shale, Sandstone and Minor Limestone Facies

Green Shale Facies

Sandstone Facies

EXPLANATION

NEBRASKAOil Field, Cambrian Reservoir

12

0

A A'

Blackfeet

Ft. Belknap Ft. Peck

Ft. Berthold

Standing Rock

MONTANA

WYOMING

SOUTH DAKOTA

NORTH DAKOTA

10

8 4

6

4

2

12 = 1200' thickness

Blackfeet Reservation, location of analog fields and location of regional cross-section

Precambrian age supracrustal sedimentary rocks (Superbelt) are buried in the western part of the reservation and extend into Glacier National Park. These rocks are estimated to be from 900 to 1400 million years old.

During Cambrian time, a major seaway existed in western Montana and eastern Idaho (see cross-section A-A' Figure BF-4.1 and map of the Cambrian). This seaway gradually transgressed from west to east across eastern Montana and

The major source of coarse-grained clastics was to the east (from the Sioux Arch) and graded into shales and limestones to the west. the Cambrian varies from over 2000 feet at the reservation to less than 100 feet

Between these two tectonic provinces lie the Fort Peck and the Fort Belknap Fork Peck is on the western flank of the Williston Basin and is

dominated by Poplar Dome, a Laramide age structure, while Fort Belknap lies

To better illustrate the geologic history of the region, which has been influenced by all of these tectonic provinces, a series of paleo cross-sections are

Each section summarizes a particular time interval; Cambrian and older Since Tertiary

sediments are present only in the Williston Basin, no paleostructure section is

A paleo cross-section attempts to show what the subsurface geology may have looked like within that time interval.

interval have not yet been deposited; the top of the section is the datum.

Generalized time slice cross-section of Cambrian paleo-topography along line of section A-A".

Blackfeet Reservation GEOLOGY OVERVIEW index topicsmapMontana Geologic History PAGE 4 of 13

Montana Geologic History Blackfeet Reservation

EXPLANATION

Pre-Cretaceous rocks exposed at land surface

Tertiary rocks present

3 34 4

30

4 5

2

0

1

3

3

4

5 43

2 1

0

00

5 6

5

5

6.5

6 54

321 0

0 1 2

3

4

3

4.5

3 2 1 0

1

1

1

0

0

0

0 0

5

6

32

Standing Rock

Gas field (Cretaceous reservoir)

SOUTHDAKOTA

NORTHDAKOTA

Ft.Berthold

Ft. Peck

A'

MONTANA WYOMING

NEBRASKA

A Blackfeet

Ft. Belknap

Figure BF-5.2.

Triassic Rocks

Permian Rocks

Prairie Salt

Silurian Rocks


Ordovician Rocks

Poplar Dome

Ordovician Rocks



Pennsylvanian Rocks

Mississippian Rocks

Bakken Shale

Devonian Rocks

Bakken Shale

Bearpaw Uplift

Sweetgrass ArchPreCambrian Rocks

114 113 112 111 110 109 108 107 106 105

BLACKFEET RESERVATIONAWEST

104 103 102 101 100

Generalized Cross-Section A-A' Triassic through Ordovician

Line of cross section along 48 degrees latitude with selected points every 1 degree of longitude

DATUM: Base of Jurassic - Permian missing


Overthrust Belt

0

1000

2000

3000

4000

5000

6000

Thi

ckne

ss o

f Sed

imen

t (in

ft)

7000

8000

EASTA'Longitude Values (in Degrees)

Williston Basin

Figure BF-5.1.every 1 degree of longitude (after C.W. O'Melveny, 1996).

Figure BF-5.3. location of regional cross-section A-A'.

SOUTH DAKOTA

NORTH DAKOTA

Approximate limit of the Bakken Formation

Ft. Peck Reservation

25

100 25

Ft. Berthold

Standing Rock

Mississippian or older rocks exposed at land surface

42

44

46

48 50

50

25

75

75

0

Ft. Belknap

Blackfeet

NEBRASKA

Thickness in feet of Bakken Formation

25

EXPLANATION

WYOMING

MONTANA

50

100o

105o110

o

A'A

0

0 0

0

0

0

25

o

o

o

Ordovician to Triassic Rocks �

The

� Devonian rocks are widespread across the area.

The

caused the formation of several hydrocarbon traps.

Bakken Shale.

oil throughout the region. feet thick at the reservation. more than 50 feet thick in this area (Figure BF-5.2). �

sequences. eastern and central Montana.

trough in Central Montana. �

1500 feet. � erosion and karstification.

Tyler sands and shales are present in the Williston. longitude 106 degrees along the line of section. � sand/shale and evaporite sequences.

degrees. present on the Blackfeet Reservation.

Jurassic to Cretaceous Rocks

� In Jurassic time, the Williston was still the major depocenter for clastic and marine/evaporite sediments. The

fairly thin, implying that the Sweetgrass Arch and Bearpaw Uplift were still positive features (see cross-section A-A', Figure BF-5.1). Fluvial sands from the eroding highlands filled paleovalleys cut in the exposed Mississippian rocks.

thick. � sheets in western Utah and eastern Idaho. The Sevier Orogenic event created a major mountain front which formed an asymmetrical basin with the long axis at the present Idaho-Montana border. Sediment from the western highlands

Deposits were mainly composed of Mississippian and older rocks, with some Cretaceous aged volcanic rocks. This

Cretaceous seaway (Lower Cretaceous, Kootenai formation). Deposition continued, becoming more marine (Mowry shale, Blackleaf sandstone). � By Upper Cretaceous time, volcanic activity increased. Fluvial deposits continued to carry sediments to the eastern

inland seaway. plains from Texas to the Arctic Circle.

Colorado. �

Fluvial deposition

and continental sands (Eagle/Judith River/Foxhills). abundant on the reservation. than 7200 feet.

Tertiary and Younger � by fluvial deposition.

Western

Montana had deposition of some continental sediments. � North Dakota and Montana. mountains. River and its tributaries.

GEOLOGY OVERVIEW index map topicsPAGE 5 of 13

Map showing thickness of Bakken Rocks, facies, location of analog fields, Blackfeet Reservation and location of regional cross-section A-A' (modified after Peterson, 1987).

Generalized cross-section A-A', line of section along 48 degrees of latitude with selected points

Map showing general distribution of Cretaceous and Tertiary rocks, Blackfeet Reservation and

From late Cambrian through most of the Paleozoic, the Williston Basin on the east side of the cross-section was the dominant receiver of sediments (see cross-section A-A', Figure BF-5.1). Williston is a major, stable, cratonic basin, and is characterized by shallow, marine sediments. Ordovician and Silurian rocks were deposited in a tidal flat, cyclic carbonate and evaporite sequence. At the end of Silurian time, a regional unconformity extended across the Williston and to the west. There are no Ordovician or Silurian rocks within the reservation boundaries.

The Devonian is characterized by cyclic evaporite

and carbonate units including the Prairie Salt sequence in the Williston. Prairie's western edge was dissolved away during late Devonian time, and

Deposition of marine shales and limestones continued throughout Devonian time, culminating with the

The Bakken, and it's Alberta equivalent, the Exshaw, is a black, organic-rich shale, which is thought to be the main source rock for the Madison

Devonian rocks including the Bakken are about 700 The Bakken/Exshaw varies from 10 feet thick to

By Mississippian time, the Williston Basin to the west was continually depositing limestones and evaporites in a shallow, marine shelf environment. Most of the producing reservoirs in the Williston Basin area are from these cyclic marine shales, limestone/dolomite porosity zones and evaporite seal

Eventually, the Charles Salt would cover the entire basin and part of By late Mississippian time, deposition was mainly

shales and mudstones confined to the central Williston and the Big Snowy

A smaller depocenter of Mississippian rocks existed west of the Sweetgrass Arch and Bearpaw uplift which were positive features in Mississippian time. Total thickness of Mississippian rocks within Reservation boundaries is about

A major unconformity at the end of Mississippian time led to widespread Pennsylvanian sediments are confined to the center of

the Williston and in central Montana south of the reservation. No Pennsylvanian rocks occur west of

Permian deposits are confined to the central Williston and are predominantly A major unconformity at the end of

Permian time has removed any evidence of these rocks west of longitude 104 Triassic rocks are confined to the center of the Williston and are not

western edge of the cross-section shows that the Jurassic was

Thickness of Jurassic rocks is estimated to be about 500 feet

Early Cretaceous time saw the development of the Thrust

were continually deposited at the foot of the mountain front.

material was carried by rivers and deposited eastward into the

This seaway covered most of eastern Montana, and the great Extensive chalk (Niobrara Formation)

was deposited in the Williston southeast into South Dakota, Nebraska and

By the end of the Upper Cretaceous, mountain building began in western Montana with increasing volcanic activity and thrust faulting. increased due to uplift and erosion and resulted in the deposition of nearshore

Cretaceous units are Estimated thickness of Cretaceous rocks is greater

Tertiary time saw the erosion of older Cretaceous rocks and is characterized Swamps existed in Paleocene and Eocene time in the

central Williston, which formed coal deposits at the end of the Eocene. Montana apparently had no Tertiary deposition while central and eastern

Quaternary time was a period of major continental ice sheets extending into Alpine glaciers existed in Montana's western

Extensive glacial lakes were present along the ancestral Missouri

7 Eagle

Judith River

Blackleaf

Sunburst

Jurassic

Cutbank

Mississippian Bakken Shale

2

5 Ellis

Devonian Duperow

Swift

Lower Cretaceous

Lower Cretaceous

Upper Cretaceous

Sun River

4

4

Disturbed Belt

Jurassic

2

1

Mississippian

1

7

3

5

Schematic Diagram of Play Types on Blackfeet Reservation PLAY TYPES - Explanation

1. Folded and Fractured

Mississippian Carbonates (2807)

2. Jurassic / Cretaceous Sands (2808)

3. Mississippian / Duperow (2805)

4. Imbricate Trust Sheets (2701)

5. Fractured Bakken (2804)

6. Cambrian Sands (2802)

7. Shallow Biogenic Gas (2811, 2812)

Sandstone

Shale

Shales, sands, and siltstones

Gas

Sweetgrass Arch

6 Cambrian

Chalk

Limestone

Dolomite

Igneous / Metamorphics

Oil

Madison 3

WEST EAST

Sandstone Lenses

Unconformity Thrust Faults

No Scale - Drawing is approximate width of Blackfeet Reservation

Figure BF-6.1. Schematic diagram of play types Blackfeet Reservation

Reservation: Geologic Province: Province Area:

Blackfeet North Central Montana, Sweetgrass Arch, Montana Disturbed Belt

( by province-1996) � Oil:

North-Central Montana Disturbed Belt 440 MMBO

Undiscovered resources and numbers of fields are for Province-wide plays. No attempt has been made

Total Production

Reservation Area: 2385 sq. miles (1,525,712 acres) � NGL: 192 MBNGL 33,000 BNGL Fort Berthold Reservation Gas: 1.1 TCFG 6 BCFG to estimate number of undiscovered fields within the

Play Type USGS Designation

Description of Play Oil or Gas

North Central Montana (62,500 sq. miles), Thrust Belt (41,400 sq. miles)

Known Accumulations

�

Undiscovered Resource (MMBOE) Field Size (> 1 MMBOE) min, median, mean

Play Probability (chance of success) Drilling depths Favorable factors Unfavorable factors

Fractured, folded anticlines in

2807 folded structures, porosity controlled by matrix or

1 not estimated

49.32 MMBO 21,506 MMCFG

1,000-6700 ft 1) confirmed play 2) structure detected on seismic

1) lack of well control 2) rough topography

Both Median: 9 MMBO (9 fields @ 1MMBO)

Field Size (>1 MMBOE)

Mississippian Carbonates

fractures. 585 MBNGL (numbers include Mississippian and Devonian Play)

3) source / reservoir rocks exists 4) thermally mature

3) porosity may vary1 MMBO(min) 3 MMBO(median) 1.2 MMBO(max)

No. of undiscovered fields (> 1 MMBOE) 3 (min) 9 (median) 17 (max) 9.4 (mean)

1 Jurassic, Cretaceous

sandstones

2

2808 stratigraphic traps; discontinuos sands, updip pinchouts. Fluvial and nearshore sandstones.

1 not estimated

134 MMBO 318 BCFG 9 MMBNGL (most from Cutbank)

1,000-4,000 ft 1) confirmed play 2) source / reservoir rock exists 3) thermally mature 4) shallow drilling targets 5) probably many fields

1) lack of well control 2) seismic may not detect

strat traps 3) porosity may vary

Both Median: 30 MMBO (15 fields @ 2 MMBO)

Field Size (>1 MMBOE) 2 MMBO(min) 20 MMBO(median) 5.3 MMBO(max)

No. of undiscovered fields (> 1 MMBOE) 6 (min) 15 (median) 28 (max) 15.8 (mean)

Mississippian and Devonian carbonates

3

2805 1) Jurassic / Mississippian unconformity traps

2) Devonian Structural Traps

1 not estimated

(see numbers from Miss.) 1300-7000 ft 1) confirmed play 2) source / reservoir rocks exist 3) thermally mature 4) structure detected on seismic

1) deeper drilling depths 2) Devonian contains nitrogen

gas 3) porosity unknown for Devonian

rocks


Field Size (>1 MMBOE) 3 MMBO(min) 21 MMBO(median) 4.8 MMBO(max)

No. of undiscovered fields (> 1 MMBOE) 3 (min) 12 (median) 21 (max) 12 (mean)

Table BF-6.1. Play summary chart.

Blackfeet Reservation index topicsNorth Dakota Play Types PAGE 6 of 13 map

Reservation: Geologic Province: Province Area: Reservation Area:

Blackfeet North Central Montana, Sweetgrass Arch, Montana Disturbed Belt North Central Montana (62,500 sq. miles), Thrust Belt (41,400 sq. miles) 2385 sq. miles (1,525,712 acres)

Total Production ( by province-1996) � Oil: � Gas: � NGL:

North Central Montana Disturbed belt 440 MMBO 1.1 TCFG 6 BCFG 192 MBNGL 33,000 BNGL

Undiscovered resources and numbers of fields are for Province-wide plays. No attempt has been made to estimate number of undiscovered fields within the Fort Berthold Reservation

Play Type USGS Designation

Description of Play Oil or Gas Known Accumulations Undiscovered Resource (MMBOE) Field Size (> 1 MMBOE) min, median, mean

Play Probability (chance of success) Drilling depths Favorable factors Unfavorable factors

0.5 not estimated

3000-19,000 ft. 1) confirmed play 2) source / reservoir rocks exists 3) thermally mature 4) structure detected on seismic

1) small accumulations to date 2) seismic intensive 3) maybe thermally over mature

(some Nitrogen Gas)

4

2701 Thrusted units forming shallow and deep anticlines

No total available from United States Geological Society

Mainly gasMontana Disturbed Belt; Imbricate Thrust Sheets

Median: 900 BCFG (10 fields @ 90 BCFG)

Field Size (>1 MMBOE) 90 BCFG(median) 366.2 BCFG(max)

No. of Undiscovered Fields (>1 MMBOE) 5 (min) 10 (median) 115 (max) 5 (mean)

0.25 0.2

Not estimated 18,000 BO / sp. mi. 47,520 BO / sq. mi. 5328 sq. mi. untested

5,000-10,000 ft. 1) Bakken exists 2) thermally mature 3) structures and flexures exist

1) no existing production within province

2) source rock unknown 3) thermal maturity unknown 4) lack of deep well control

Fractured Bakken

5

2804 Bakken / Exshaw shale high organic content, thermally mature; fractured reservoir

Not applicableOil

Cambrian Sands

6

2802 Coarse sands trapped as pinchouts or on deeper structures

0.5 not estimated

Not applicable 1,700-7000 ft. 1) reservoir rock exists 2) structures exist 3) structure detected on seismic

1) no exciting production within province

2) source rock unknown 3) thermal maturity unknown 4) lack of deep well control


Field Size (>1 MMBOE) 1 MMBO (min) 5 MMBO(median) 1.3 MMBO(max)

No. of Undiscovered fields (> 1 MMBOE) 1 (min) 2 (median) 4 (max) 1.1 (mean)

Shallow Biogenic Gas

7 2811 2812

Accumulation in Upper Cretaceous units; Eagle, Judith River, Niobrara

1 0.50-0.70

504,000 MMCFG from numerous fields in province

700-3000 ft. 1) source rock / self source 2) reservoir rock exists 3) shallowing drilling depths 4) occasional gas shows

1) size of accumulation unknown 2) porosity decreases with depth 3) exposed to atmosphere

possible leakage 4) tracking mechanism

Biogenic Gas Median: 280 BCFG (14 fields @ 20 BCFG)

Field Size (>1 MMBOE) 20 BCFG(median) 27.4 BCFG (max)

No. of Undiscovered fields (> 1 MMBOE) 5 (min) 14 (median) 26 (max) 14 (mean)

Table BF-7.1. Play summary chart.

Conventional play type

Unconventional/Hypothetical play type

Blackfeet Reservation Play Types PAGE 7 of 13 index topicsmapMontana

EAST-WEST CROSS SECTION REAGAN FIELD

"A" Sand

"B" Sand

Top Blackleaf

Top Colorado

Top Ellis

Top Madison

Cut Bank Sand

+2000

+1900

+3000

+2900

+2800

UNION Tribal 19-4 No. 13

Elev. 4108'

Moulton Sand

+1700

+1600

+700

+600

+500

+400

Mont. Power Tribal 355 No. 7

Elev. 4017'


Elev. 4054'


Elev. 4067'


Elev. 4106'

+375

+400

+150

REAGAN FIELD Glacier County, Montana

MADISON STRUCTURE C.I. = 25 feet

+400

+325

UP DOWN

MADISON DISCOVERY

CAMBRIAN TEST

BLACKLEAF "A" SAND DISCOVERY

+200

+175

RIERDON

SAWTOOTH

UPPER CUT BANK

LOWER CUT BANK

MADISON CONTOUR DATUM

JUR

AS

SIC

BOW ISLAND

BLACKLEAF "A"

SAND

SAND

CONE M.

FLOWREE M.2200

2400

T 37 N

+350

MIS

SIS

SIP

PIA

N

SU

N R

IVE

R D

OL

OM

ITE

FA

CIE

S

CR

ET

. C

RE

TA

CE

OU

S

Madison Oil Well

Blackleaf "A" Sand Gas Well

Dry Hole

Madison Discovery

Injection Well

+400

CANADA

USA

BOW ISLAND SAND PROD.

3500

4000

+350

+375

+400

R 7 W

Blackleaf "A" Sand Discovery

LEGEND

234

WELLS USED FOR CROSS-SECTION

+325

6-1

888

I-1

899

878

7-3 917

I-2x

I-2

7-1T 37 N

922

918

880

890

7-2

7-4

930

916

2-2 2-1

RIERDON

MADISON

CUT BANK

SUNBURST SAND

I-3

914

926

1-4

930

OIL WELL

DRY HOLE

ABANDONED OIL WELL

LEGEND

907874

3-3

3-1

890

902

4-2 5-1

Blackfoot Field Glacier County, Montana

Cutbank Sandstone Structure C.I. = 10 feet

DUNOCO

DUNOCO

613

9-1

906

Union Oil of California MUNTZING No. 1 (6-1)

Elev: 4225

920

900 910

3-2 4-1

883 891

R6W

35003400

3300

919

8-1

3400

MADISON

RIERDON

CUT BANK

SUNBURST SAND 3300

BLACKFOOT FIELD GLACIER COUNTY, MONTANA

CROSS SECTION A-A'

DATUM - SEA LEVEL

MURPHY CORP. Muntzing B-3 (7-3)

Elev. 4173

3300

3400

MURPHY CORP. Muntzing 1-B (7-1)

Elev. 4191

3500

3400

SUNBURST CUTBANK

DU

3600

3700 RIERDON

WAGGNER-LANSFORD Gov't No. 1 (1-1)

Elev. 4243

DUNOCO INC. Belke No. 3 Elev. 4222

Blackfeet Field Type Log Glacier County, Montana

Cutbank Sandstone Madison Sun River Dolomite

TYPICAL ELECTRIC LOG MURPHY CORPORATION

#1-B Muntzing

Sunburst Sand

Cut Bank Sand

Moulton Sand 3200

3250

Rierdon

Sawtooth

GAS

OIL 3300

3350

3400

3450

GAS

OIL

3150

Madison

Figure BF-8.2. Type log from the Blackfoot Field showing production from both Madison carbonates and from younger karst-related sandstone deposits.

Figure BF-8.4. Cut Bank sandstone.

Figure BF-8.3. Structure contour map of Blackfoot Field. Datum is top of Cut Bank sandstone. Shows position of cross-section A-A' in Figure BF-8.4.

Figure BF-8.1. Source rocks on the Arch

TABLE BF-1. Reagan Field Parameters Formation: � � � � Average Depth: 3900 ft. (+375) Lithology:� � � � Porosity:� � 12% Oil/Gas Column: � Permeability:� � 10 md � � � � 68 ft. gas column (original)�Other Shows:� � Blackleaf "A" Average Net Pay Thickness:� 20 feet� � � � � � Sand, Madison

Montan Blackfeet Reservation

PLAY TYPE 1

Fracture / Folded Anticline Mississippian Carbonate Play

General Characteristics - This play consists of folded or fractured Madison limestones or dolomites.

porosity that developed during post-Mississippian erosion. Source rock along the

or marine Lodgepole limestone. �

enhanced fracture porosity.

ANALOG FIELDS (*) denotes fields within the Reservation boundaries)

Reagan Field * 9.3 MMBO, 15 MMcf� 54 wells

Blackfeet Field 1.6 MMBO, 3.0 MMcf� 8 wells oil, � � � � � � � � � � � 7 wells gas

Gypsy Basin� (Sweetgrass Arch)� 504,783 BO, 3.1 MMcd� 4 wells

Red Creek� (Sweetgrass Arch)� 6.5 MMBO, 1.2 MMcd� 18 wells oil

A A'


Cross-section A-A' showing the fault-assisted closure within the Blackfoot Field of the

Source rock along the Sweetgrass Arch is thought to be the black, organic Bakken/Exclaw shale or marine Lodgepole limestone. are considered mature, while those in the Montana disturbed belt are overmature. Typical traps are folded Madison rocks, with enhanced fracture porosity.

Madison�� Dolomite��

�� 52 foot oil column��

Reservoir rock consists of either (1) sub-tidal carbonate beds with enhanced porosity zones due to dolomitization or (2) paleokarst

Sweetgrass Arch is thought to be the black, organic rich Bakken /Exchaw shale,

Source rocks on the Arch are considered mature, while those in the Montana disturbed Belt are overmature. Typical traps are folded Madison rocks, with

� (Sweetgrass Arch)�

� (Sweetgrass Arch)�

CONVENTIONAL PLAY TYPE 1 Fracture / Folded Anticline Mississippian Carbonate Play

Blackfeet Reservation Jurassic/Cretaceous Sandstone Play

4

7

2

+633

+649

2

6 +632

+666

5

1

6

+630

2

GLACIER COUNTY

PONDERA COUNTY

35

1

500

11

26

12

2 5

4

4

6

36

13

3

SW Cut Bank Field Glacier & Pondera Counties, Montana

C.I. 20 ft. STRUCTURE - ELLIS

32 33

5 4

400

T 32 N

34

2829 27

3

98 300 10 T 31 N

R 6 W

ELLIS

GROUP

MADISON

BANK

MOULTON +1700

+1600

+1500

+1400

+1300

+1200

+1100

+1000

+900

+800

+700

+600

+1800

NE-SW 3-35N-4W

4149 KB

NW-SW 19-35N-4W

4026 GL

C-NW 11-35N-5W

4070 KB

NE-NW 19-35N-5W

4133 KB

+500

+400

CUT BANK FIELD

DIAGRAMMATIC CROSS SECTION A-A' Glacier and Toole Counties, Montana

SUNBURST

MOULTON

ZONE

SAND

CUT

MO

ULTO

N

WEST 20-35N-6W

3927 KB

C-SE 13-35N-6W

3955 GL +1900

EAST SW-NE

1-35N-4W 4166 KB

MOULTON

MS

L E

LEV

AT

ION

A A'

T 35 N

T 34 N

T 33 N

Waterline in Cut Bank Sand

CUT BANK FIELD GLACIER & TOOLE Co., MT

GENERALIZED ELLIS STRUCTURE

CONTOUR INTERVAL = 50'

10 MV/DIV 0 OHMS-M 100

A

MOULTON

SUNBURST

CUT BANK A'DISCOVERY WELL

GAS FIELD

+1300

+1400

+1500

+1200

DISCOVERY WELL OIL FIELD

+1100

AP

PR

OX

IMA

TE

EA

STE

RN

LI

MIT

BLA

CK

FO

OT

IND

IAN

CU

T

BA

NK

S

AN

D

2700 2800

2900 3000

ELLIS

MADISON

T 36 N

T 37 N

TYPE LOG ELMER No. 1

NE NW 3-36N-5W

+1200

+1100

+1000

+700 +600

+500

RE

SE

RV

AT

ION

BO

UN

DA

RY

+1000

T 32 N +900

+800

R 6 W R 5 W R 4 W

2600

Figure BF-9.3.

Society, 1981).

Figure BF-9.2.

PLAY TYPE 2

Jurassic/Cretaceous Sandstone Play

General Characteristics - This play is the major producing interval on the Sweetgrass Arch. sandstones in the Jurassic Sawtooth and Swift formations.

� structural trends.

Source rock is thought to be

Analog Fields�

Reagan Field * Sunburst and Cut Bank Sands Blackfoot Field Cut Bank Sands Cut Bank*� (Sweetgrass Arch)� Cut Bank sands (est 15% with � � � � � � � � � boundary)167.3 MMBO, 317 MMcf, 447 � � � � � � � � wells oil, 235 wells gas Kevin Sunburst Cumulative production (1985) 74.9 � � � � � � MMBO more than 79.5 MMcf (1963) � � � � � � Nisku (1 well), Madison (795 wells) � � � � � � Swift (25 wells) Soberup Coulee�(Sweetgrass Arch)� 21,853 Mcf (abn'd) Gypsy Basin� (Sweetgrass Arch)� Sunburst Sand

Figure BF-9.1. Structure map of the Cut Bank Field, showing the structural and stratigraphic position of Cut Bank sandstone deposits related to underlying Karst development within the Madison carbonates (after T.G. Cully, Montana Geological Society, 1984).

SW Cut Bank Field Parameters

Formation:� Cut Bank

Lithology:� Cretaceous Cut Bank Sandstone, � blanket sand which pinches out � updip

Average Depth:� 3900 feet (+375)

Porosity:� Moulton: 19-20% � Sunburst:14-24% � Lander: 18-24% � Cut Bank: 12-19% � Madison: 10%

Permeability:� Cut Bank: 1 to 450 md

Oil/Gas Column:� Information not available

Average Net Pay Thickness:� 27 feet

Cut Bank Field Parameters

Formation:� Cretaceous Cut Bank Sandstone � Colorado Group sands (Moulton, � Sunburst, Lander) � Mississippian Madison

Lithology:� Cretaceous Cut Bank Sandstone, � blanket sand which pinches out updip

Average Depth:� 3900 feet (+375)

Porosity:� Moulton: 19-20% � Sunburst: 14-24% � Lander: 18-24% � Cut Bank: 12-19%

Permeability:� Moulton - 200 md � Sunburst - not known � Lander - 827 md � Cut Bank - 110 md � Madison - not known

Oil/Gas Column:� 52 foot oil column � 68 foot gas column (original)

Average Net Pay Thickness:� Variable with formation

Montana index map topicsPAGE 9 of 13

SW Cut Bank Field showing stratigraphic pinch-outs in the updip direction which correspond to the distribution of production (after W.L. Foley, Montana Geological

Cut Bank Field diagrammatic cross-section A-A' showing discontinuous nature of sandstone development across structure (after T.G. Cully, Montana Geological Society, 1984).

Stratigraphic in nature, typical traps are discontinuous fluvial Sandstones in the

Cretaceous Kootenai and Blackleaf intervals are also productive. Several traps are blanket sandstones that pinchout in an updip position along

Numerous smaller fields are probably present on the flanks of the Sweetgrass Arch and the Kevin-Sunburst Dome. Cretaceous marine shales which are thermally mature across the region.

(*) denotes fields which lies within the Reservation boundaries)

� (Sweetgrass Arch)� � (Sweetgrass Arch)�

� (Sunburst Dome)� �

CONVENTIONAL PLAY TYPE 2

Montana Devonian / Blackfeet Reservation

SWIFT SANDSTONE

SWIFT SHALE

MADISON

RIERDON

NORTH-SOUTH STRUCTURE CROSS SECTION

PONDERA FIELD Illustrating hypothetical mode of structure and oil occurrence beneath pre-Jurassic unconformity

Impermeable - barren

Permeable - fluid bearing

Oil - water contact

+2000

+1900

+1800

+1850

+2100 A

North South

A' 5 MILES

DIAGRAMMATIC CROSS SECTION KEVIN SUNBURST DOME

MADISON

SAWTOOTH

RIERDON

SWIFT

MORRISON

TYPICAL LOG KEVIN-SUNBURST FIELD

CAMBRIAN

)

0

1000 MISSISSIPPIAN

JURASSIC

CRETACEOUS EAGLE

COLORADO

BOW ISLAND

BURWASH

SUNBURST

MADISON

1000

2000

3000

0 Mean Sea Level6 Miles

KOOTENAI

1500

1400

RIERDON

SWIFT

SoutheastNorthwest

3000

2000

MORRISON

1300

1600

SUNBURST

SAWTOOTH

2

R3W R2W R1W

KEVIN - SUNBURST DOME Toole County, Montana

STRUCTURE CONTOURS ON MADISON LIMESTONE C.I. = 100 FT

OIL PRODUCING AREA

GAS PRODUCING AREA

+ 1400

R4W R1E R2E

T 36 N

T 35 N

T 34 N

T 33 N

T 32 N

T 31 N

+ 1400

Figure BF-10.3.

PLAY TYPE 3 Devonian / Mississippian Carbonate Play

General Characteristics - Very little Devonian production has been found to date.

A Mississippian

Analog Fields (*) denotes fields within Reservation

Gypsy Basin� � � 504,783 BO, 3.1 MMcf, 4 wells (Sweetgrass Arch)� � contain shows in Devonian rocks

Kevin-Sunburst� � � Contains 1 Devonian Nisku producer Blackleaf Canyon

Pondera Field� � � 22.5 MMBO, 224,702 Mcf, 361 wells (Sweetgrass Arch), 1984

Figure BF-10.1.Madison carbonates.

Figure BF-10.2.

Geological Society, 1985).

Pondera Field Parameters

Formation:� Mississippian Sun River

Lithology:� Light gray to buff, finely crystalline � to sugary dolomite, 140ft. thick

Average Net Pay Thickness:� 10 feet

Other shows:� Bow Island Sand � Kootenai channel sands, Sun River

Average Depth:� 1950 feet (+1820 msl)

Porosity:� 14%

Permeability:� 82 md

Oil/Gas Column:� 70 to 100 foot oil column

of a Laramide structural terrace.�

Kevin-Sunburst Field Parameters

Formation:� Mississippian Madison

Lithology:� Dolomitic limestone, varies from dense, to coarse � crystalline to intragranular to vuggy to fracture � porosity. Secondary porosity also is important � locally

Average Net Pay Thickness:� 10 feet porosity

Other shows:� Bow Island Sand Burwash, Sunburst � Swift, Reirdon, Sawtooth, Madison, Nisku, � Duperow

Average Depth:� 1500 feet (+2000 msl)

Porosity:� 20%

Permeability:� variable

Oil/Gas Column:� from +1400 to 2150 feet in the Madison

+ 1600

+ 1800

+ 1600

+ 1800

+ 2000

index map topicsPAGE 10 of 13Mississippian Carbonate Play

DUPEROW (CO

NISKU (Oil & Gas)

Kevin-Sunburst Dome (after Montana Geological Society, 1985).

Probably found on structures, and numerous shows have been recorded on deep tests at Kevin-Sunburst Gypsy Basin and Highview Fields. play on the Madison unconformity surface is also a distinct possibility. Corresponds to the same United States Geological Survey play classification.

North-south structure cross-section, Pondera Field showing position of permeable, karsted

Typical log, Kevin-Sunburst Field and diagrammatic cross-section. Shows both the Karst-related (Madison) distribution of sandstone reservoirs and development of channel-related (Cretaceous) sandstone horizons (from Montana

This field is a pre-Jurassic truncation of folded Mississippian rocks, and part This field has numerous pay zones with both a structural and stratigraphic influence. While the Kevin Sunburst Dome does not exist on the reservation, the local variations in reservoir rock make smaller structural and stratigraphic traps likely possible.


Montana Montana Disturbed Belt - Imbricate Thrust Blackfeet Reservation

Sawtooth

Sawtooth Sun River

Sun River

Madison

Madison

Sun River

Sawtooth Jurassic

Mississippian

Madison

GREAT NORTHERN Blackleaf Tribal 1

RAINBOW Big Springs

Two Medicine #1-30

SOUTH A

NORTH A'

-3600

-3800

-4000

-4200

-4400

-4600

-4800

DISCOVERY UNION

#588 Morning Gun RAINBOW

Two Medicine 1-18

RAINBOW Two Medicine 1-19

9260 TD

TWO MEDICINE FIELD

Glacier Co., MT

CROSS SECTION A-A'

9453'TD 9244' TD 9383' TD9559' TD

-4057

RAINBOW Big Springs Two Medicine 1-30

-4237



-4042

-4300

-4400

-4500

-4600

EAST GLACIER FIELD

TWO MEDICINE FIELD

WILLIAMS 2-3 Federal

(UK Greenhorn completion)

SHELL-UNION Lewis 32x-10


(Produces from UK Greenhorn, 6766-7276')

DISCOVERY UNION #588 Morning Gun-4100

GREAT NORTHERN Blackfeet TR 1

-4100

HUMBLE 10-Y Blackleaf Tribal

-4100

-4300

-4645

-4143

-4658

-430

0-440

0

-450

0-460

0

-4373

-5879

-4612

-470

0

R 12 W R 11 W

T 31 N

MONTANA POWER Two Medicine 1-11

A

A'

-4200

SUN RIVER STRUCTURE

Contour Interval = 100 ft

36 31

1 6

-500

-300

-1000 -500

Williams Exploration 1-5 Blackleaf Unit



Burlington Northern 11-18 Blackleaf A

No. Natural Gas 1 Blackleaf Fed. A

4

9

56

7

General Petroleum 1 Blackleaf

1211

2 1

-200


DISCOVERY No. Natural Gas Blackleaf Fed. B

Woods Petroleum #1 Volcano Reef

14 13

2423 2019

-1208

-408

-130

2526

-100

18 17

-1000

1000

-1500

T 26 N

T 27 N

35

2 1

-86 21

-500

G/W

-497 U D

-46

-575

DISCOVERY Rainbow Resources 1-8 Blackleaf Fed

0

+ 12

Gulf Oil 1 Teton Knowlton

-830

R 9 W R 8 W

29 28

Mobil 5-1 Federal

3236 31

6 5

-1500

-200

G / W

LEW

IS A

ND

CLA

RK

NA

TIO

NA

L F

OR

ES

T

BLACKLEAF CANYON FIELD

BLACKLEAF UNIT

SUN RIVER STRUCTURE "A" THRUST SHEET

Contour Intervals: 100 & 500 ft

T 25 N

30

+1500

+1000

29

3231

61

Mobil 5-1 Fed

Northern Natural Gas Blackleaf Fed B

2019

Williams Exploration I-19 Blackleaf Unit

Woods Pet. #1 Volcano Reef

24

25

23

26

General Pet. 1 Blackleaf

14 DISCOVERY No. Natural Gas 1 Blackleaf Fed.

13

11 12

+1545

+500

Williams Exploration I-16 Blackleaf Unit

21

T 26 N

+1608

17

R 9 W R 8 W

-1500

-1000

Burlington Northern 11-18 Blackleaf A

1000

500


1 6

7 8 9

18

Gulf Oil 1Teton Knowlton

45

-575

16

DISCOVERY Rainbow Resources 1-16 Blackleaf Fed.

+535

+1500

+1459

G/W

35 36

LEW

IS A

ND

CLA

RK

NA

TIO

NA

L F

OR

ES

T

2

2

BLACKLEAF CANYON FIELD

BLACKLEAF UNIT

T 25 N

28


-830

-46

-497

U D

T 27 N

+12

G / W

G / W

+1000

SUN RIVER STRUCTURE "B" THRUST SHEET

Contour Interval: 500 ft

PLAY TYPE 4

Montana Disturbed Belt - Imbricate Thrust

General Characteristics - Imbricate, or angled thrust sheets and corresponding

summarize this play. and Two Medicine complex and Blackleaf Complex. � 500 feet thick. found. Jurassic and Cretaceous sandstones may produce. �

% TOC. � than 3000 feet on the eastern side. equivalent rocks in Canada. structures in the Disturbed Belt.

Analog Fields (*denotes field inside Reservation boundaries) Two Medicine� 11,510 BO � 275,000 Mcf (Abn'd)� (Montana Disturbed Belt) Blackleaf � 33,748 BO � (Montana Disturbed Belt)

Field BF-11.3. Blackleaf Canyon Field (after James W. Garner, Montana Geological Society, 1985).

Figure BF-11.4 Blackleaf Canyon Field (after James W. Garner, Montana Geological Society, 1985).

Figure BF-11.1.Geological Society, 1985).

Figure BF-11.2.

Blackleaf Canyon Field Parameters

Formation: � Mississippian Sun River

Lithology:� � East Sun River, 420 feet

Average depth: � West Sun River "A" thrust sheet � 3900 feet. (+1537 feet MSL) � West Sun River "B" thrust sheet 5700 feet � (-200 feet MSL) � East Sun River 5028 feet (-28 feet MSL)

Porosity: � West Sun River 3.5% matrix porosity � East Sun River 3.5% matrix porosity

Permeability: � not known

Oil/Gas Column: � West Sun River "A" (100 feet MSL) � West Sun River "B" (350 feet +1450 MSL) � East Sun River 350 feet (-450 feet MSL)

Average Net Pay: � Sun River 350 feet thick

Two Medicine Field Parameters

Formation: � Cretaceous Greenhorn, Mississippian Sun River

Lithology: � Greenhorn - fractured sandstone and shale, 600 � � feet. Continuous except when faulted � Sun River - fractured dolomite, 225 feet � Continuous except when faulted

Average Depth:� Greenhorn - 7000 feet (-2000 feet MSL) � Sun River - 8800 feet (-4050 MSL)

Porosity: � Greenhorn - 15% Sun River - 9% average � matrix

Permeability: � not known

Oil/Gas Column:� Greenhorn - 375 feet (water contact not known)� � �Sun River- 125 feet (water contact not known)

Average Net Pay:� Greenhorn - 100 feet Sun River - 90 feet

TWO MEDICINE and

EAST GLACIER FIELDS

Glacier Co., Montana

DISCOVERY RAINBOW

Two Medicine 1-11 (Produces from UK Greenhorn

6900-7155')


anticlines between the Lewis Thrust Sheet, and the eastern edge of the Disturbed belt Only three known fields exist in this province: the East Glacier

Potential reservoir rock is dolomitized Mississippian limestone between 200 and Permeability is low which may explain the small accumulation

Lower Mississippian and Devonian rocks may have fractured reservoirs.

Source rock is thought to be either (1) the Flood member of the Cretaceous Blackleaf formation (43 - 168 feet thick) with 1.1 % total organic carbon (TOC); (2) shale member of the Jurassic Swift formation (6 - 32 feet thick) with 1.1 % TOC; or (3) Devonian Bakken/Exshaw organic rich shale (10 - 40 feet thick) averaging 0.97

Depths to potential reservoirs vary from 19,000 feet on the western side to less Carbon dioxide gas has been found in the

Some carbon dioxide has been found in smaller

7.0 MMcf (Abn'd) �� Two Medicine and East Glacier Fields (after James W. Garner, Montana Two Medicine Field (after James W. Garner, Montana Geological Society, 1985).

West Sun River dolomite, �continuous, 450 feet


Montana Blackfeet Reservation

POPLAR DOME

CEDAR CREEK ANTICLINE

ANTICLINE

UNITED STATES

CANADA

PRYOR UPLIFT BIG

HORN MTNS

MT

WY

BLACK HILLS UPLIFT

ND

SD

106

NORTHERN LIMIT POWDER RIVER BASIN

WILLISTON

BASIN

OF

48

47

46

45

44

48 104 102

BEARPAW MTNS

CAT CREEK ANTICLINE

SWEETGRASS HILLS

BOWDOIN DOME

LITTLE ROCKY MTNS

PORCUPINE DOME

CENTRAL MONTANAUPLIFT

A A'

108

WE

STE

RN

LIM

IT

110

BEARPAW MTNS

DOWDOIN DOME

FOX HILLS SS

BEARPAW SHALE

ST MARY RIVER FM

JUDITH RIVER FM

ARDMORE BENTONITE BED

PIERRE SHALE

WEST FLANK WILLISTON BASIN

HELL CREEK FM.

CLAGGETT SHALE

EAGLE SS

VIRGELLE SS

MARIAS RIVER SHALE

TELEGRAPH CREEK FM.

GAMMON SHALE

NIOBRARA FM

MOWRY SHALE

CARLILE SHALEBELLE FOURCHE SH

BLACKLEAF FM

VAUGHN MBR

MUDDY SS

SKULLCREEK SHALE

Upper CretaceousLower Cretaceous

GREENHORN FM

TW

O M

ED

ICIN

E F

OR

MA

TIO

N

BEARPAW SHALE HORSETHIEF SANDSTONE FOX

HILLS SS

WILLOW CREEK FM (PART)

NONMARINE ROCKS

COASTAL SANDSTONE

CALCAREOUS SHALE CHALK & LIMESTONE

MARINE SHALE & SILTSTONE

90 Mi 150 Mi180 Mi

GLACIER NAT'L PARK

A A'

0

0

0

10

15

12

10

0

2

2 6

12 10 15

8

10

8

10

Cambrian and older rocks exposed at land surface

Shale, Sandstone and Minor Limestone Facies

Green Shale Facies

Sandstone Facies

EXPLANATION

NEBRASKAOil Field, Cambrian Reservoir

12

0

A A'

Blackfeet

Ft. Belknap Ft. Peck

Ft. Berthold

Standing Rock

MONTANA

WYOMING

SOUTH DAKOTA

NORTH DAKOTA

10

8 4

6

4

2

SOUTH DAKOTA

NORTH DAKOTA Approximate limit of the Bakken Formation

Ft. Peck Reservation

25

100 25

Ft. Berthold

Standing Rock

Mississippian or older rocks exposed at land surface

42

44

46

48 50

50

25

75

75

0

Ft. Belknap

Blackfeet

NEBRASKA

Thickness in feet of Bakken Formation

25

EXPLANATION WYOMING

MONTANA

50

100o

105o110

o

A' A

0

0 0

0

0

0

25

o

o

o

o

Figure BF-12.3. Thickness of Bakken formation (uppermost Devonian and Figure BF-12.4. Cretaceous cross-section (after Rice and Shurr, 1980).

Figure BF-12.1. Thickness of Bakken formation (uppermost Devonian and lowermost Mississippian) (modified after Peterson, 1981,1984).

PLAY TYPE 5 Fractured Bakken Shale Play General Characteristicsorganic rich marine shale, The Bakken is

feet deep.

PLAY TYPE 6 Cambrian Sandstone Play

General Characteristics - Cambrian sandstones are more than 2000 feet thick in the Disturbed belt part of the Reservation. sandstones from the Flathead formation. and 8000 feet. Cambrian Gordon formation. content or thermal maturity.

PLAY TYPE 7 Biogenic (Low, Medium, High Potential) Gas Play

General Characteristics - Shallow biogenic (methane rich) gas produces at

grading to fine sands and silts.

and look poor on well logs.

reservoirs.

Bakken, Cambrian Sandstone and Biogenic Gas Plays

Figure BF-12.2. Blackfeet reservation and location of

UNCONVENTIONAL / HYPOTHETICAL PLAY TYPES 5, 6, 7 index map topicsPAGE 12 of 13

112û

lowermost Mississippian), in feet (modified after Peterson, 1981,1984). Major structural elements of northern Rocky Mountain Region and location of

- The Devonian Bakken, one of the probable source rocks for the Madison, is an regionally equivalent to the Alberta Shelf, Exchaw shale.

considered to be thermally mature across the Sweetgrass Arch, and varies from less than 10 feet thick to over 75 feet thick in the northern portion of the Blackfeet Reservation. Depths vary from 1500 to 6000

Fractures would occur along hinge lines in the basin or on the crests of structures.

Reservoir rocks are quartz and lithic Depth to Cambrian is between 3000

Source rock is thought to be dark gray marine shales in the No information is available on source rock organic

Traps could be structural closures or pinch-outs.

Bowdoin Dome and Cedar Creek Anticline from the Cretaceous Eagle and Judith River sandstones. Traps are stratigraphic and consist of coarse clastic sands

Methane is generated soon after burial and is preferentially trapped in the coarse facies. The reservoirs are shallow and tight

A pay section may not yield gas shows when drilled. "Sweet spots" on structural highs (with paleothinning) probably localized better

This potential for traps in fine grained reservoir rocks also exists.

Thickness of Deadwood and equivalent rocks, location of analog fields. regional cross-section A-A' (modified after Peterson, 1981, 1984).

____________, 1985, "Gypsy Basin North Field", Montana Oil and Gas Field Blackfeet - Map References Symposium, Montana Geological Society, Billings, Montana, pp. 577-578. BLACKFEET RESERVATION

Executive Reference Map 334, 1985 edition, Extended Area, Northern Rocky General References ____________, 1985, "Highview Field", Montana Oil and Gas Field Mountains, Geomap Company. Symposium, Montana Geological Society, Billings, Montana, pp. 615-616

Anderson, Robert C., 1995, The Oil and Gas Opportunity on Indian Lands- Executive Reference Map 321, 1983 edition, Southern Williston Basin, Geomap Exploration Policies and Procedures: Bureau of Indian Affairs, Division of Cully, Timothy G., 1985, "Cut Bank Field (Gas)", Montana Oil and Gas Field Company.Energy and Mineral Resources, General Publication G-95-3, 158 p. Symposium, Montana Geological Society, Billings, Montana, pp. 407-408

Indian Land Areas, 1992, United States Department of the Interior-Bureau of Beeman, William R., et al., 1996, Digital Map Data, Text and Graphical Images Dyman, T.S., 1996, "North-Central Montana Province (028)", Tabular Data, Indian Affairs.

in Support of the 1995 Assessment of United States Oil and Gas Resources, Text, and Graphical Images In Support of the 1995 National Assessment of United States Geological Survey, Digital Data Series DDS-35, CD ROM. United States Oil and Gas Resources, United States Geological Survey, Clayton, Lee, et al., 1980, Geological Map of North Dakota Survey.

Digital Data Series DDS-36, CD ROM.Charpenteir, Ronald R., et al., 1996, Tubular Data, Text, and Graphical Images Darton, ., et al., 1951, Geologic Map of South Dakota, United States Geological

in Support of the 1995 National Assessment of United States Oil and Gas Editors, 1985, "Cut Bank South Central Sand Unit Field", Montana Oil and Gas Survey.Resources, United States Geological Survey, Digital Data Series DDS-36, Field Symposium, Montana Geological Society, Billings, Montana, CD ROM. pp. 407-408. Ross, Clyde P., et al., 1958, Geological Map of Montana, Montana Bureau of

Mines. Gautier, Donald L., et al., 1996, 1995 National Assessment of United States Oil ____________, 1985, "Reagan Field", Montana Oil and Gas Field Symposium,

and Gas Resources - Results, Methodology, and Supporting Data, United Montana Geological Society, Billings, Montana, pp. 937-939.States Geological Survey Digital Data Series DDS-30 Release 2.

Foley, W.L., 1958, "SW Cut Bank", Montana Oil and Gas Symposium, Montana _______________., et al., 1995, 1995 National Assessment of United States Oil Geological Society, Billings, Montana.

and Gas Resources, Overview of the 1995 National Assessment of Potential Additions to Technically Recoverable Resources of Oil and Gas - Onshore Garner, James W., 1985, "Blackleaf Canyon Field", Montana Oil and Gas Field and State Waters of the United States, United States Geological Survey Symposium, Montana Geological Society, Billings, Montana, pp. 251-256. Circular 1118, 20 p.

____________, 1985, "Two Medicine (East Glacier) Field", Montana Oil and Mallory, William Wyman, et al., 1972, Geologic Atlas of the Rocky Mountain Gas Field Symposium, Montana Geological Society, Billings, Montana,

Region, Rocky Mountain Association of Geologists , 331 p. pp. 1139-1143.

Peterson, James A. and MacCary, Lawrence M., 1987, "Regional Stratigraphy Hedglin, Bill, 1985, "Blackfoot Field", Montana Oil and Gas Field Symposium, and General Petroleum Geology of the U.S. Portion of the Williston Basin Montana Geological Society, Billings, Montana, pp. 243-246.and Adjacent Areas", Williston Basin: Anatomy of a Cratonic Oil Province, Rocky Mountain Association of Geologists, pp. 9-43. Jones, M.K., 1985, "Kevin Sunburst Field", Montana Oil and Gas Field

Symposium, Geological Society, Billings, Montana, pp. 655-660. Rice, Dudley D. and Shurr, George W., July 1980, "Shallow, Low-Permeability

Reservoirs of the Northern Great Plains - Assessment of their Natural Gas Leskla, Willard, 1958, "Pondera Field", Montana Oil and Gas Field Symposium, Resources", American Association of Petroleum Geologists Bulletin, Montana Geological Society, Billings, Montana, pp.885-888.Volume 64/7, pp. 969-987.

McCourt, J.H., 1958, "Reagan Field", Montana Oil and Gas Field Symposium, Willette, Donna C., et al., 1996, "Oil and Gas Atlas on Indian Lands", Indian Montana Geological Society, Billings, Montana, pp.203-205.

Resources Building Partnerships, Sixth Annual Energy and Minerals Conference, Bureau of Indian Affairs, Division of Energy and Mineral Nordquist, J.W., 1958, "Gypsy Basin Field", Montana Oil and Gas Field Resources, p. 10. Symposium, Montana Geological Society, Billings, Montana, pp.154-155

Perry, William J., 1996, "Montana Thrust Belt Province (027)", Tabular Data, Blackfeet - Fields and Articles Text, and Graphical Images In Support of of the 1995 National Assessment

of United States Oil and Gas Resources, United States Geological Survey, Anderson, Robert C., 1995, "Blackfeet Indian Reservation- Blackfeet Tribe"; Digital Data Series DDS-36, CD ROM.

The Oil and Gas Opportunity on Indian Lands-Exploration Policies and Procedures, Bureau of Indian Affairs, Division of Energy and Mineral Reed, W.G., Jr., 1958, "Blackfoot Field"; Montana Oil and Gas Field Resources, General Publication G-95-3, pp. 7-11. Symposium, Montana Geological Society, Billings, Montana, pp.73-75

Chamberlain, Virgil R., 1985, "Gypsy Basin Field"; Montana Oil and Gas Field Tonneson, John J., 1985, "Soberup Coulee Field"; Montana Oil and Gas Field Symposium, Montana Geological Society, Billings, Montana, pp. 573-576. Symposium, Montana Geological Society, Billings, Montana, pp. 1081

1083.

Blackfeet Reservation index topicsREFERENCES PAGE 13 of 13 mapMontana

blackfeet reservation list of topics - …...the cut bank field, which extends from townships 31 to...

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