The Niobrara Formation in the Southern Powder River Basin, Wyoming: an Emerging Giant Continuous Petroleum Accumulation

The Niobrara Formation in the Southern Powder River Basin, Wyoming: An Emerging Giant Continuous Petroleum Accumulation

Steve Sonnenberg Colorado School of Mines Halo Reservoir Tight Shale==Chalk Systems Very low matrix K Low matrix k Analogous to shale gas Thin bed, bioturbated Source = reservoir Source ≠ reservoir Migrated HC’s Examples: Niobrara, Clastics or Carbonates Austin Chalk, Eagle Ford, Ex: Codell, Turner, Vaca Muerta, Permian Cardium Wolfcamp, Bazhenov

Unconventional Light Oil ~40 API

Hybrid Shale Fractured Shale Systems Extremely low matrix Low matrix k k; primarily fracture k Analogous to tight gas Source = ≠ reservoir Source ≠ reservoir Clastics or Carbonates Example: Pierre Shale Ex: Bakken The Niobrara-Mancos Oil & Gas Play, Rocky Mountain Region Niobrara & Fracture Fields Florence Cañon City (Pierre Shale; Nio source) • 1862 • 15.3 MMBO Boulder (Pierre Shale; Nio source) • 1901 • 1 MMBO Rangely (Mancos/Niobrara) • 1902 • 11.7 MMBO, 12.2 BCF Salt Creek (Niobrara +) • 1907 • “Upper shale” Cretaceous Tow Creek (Niobrara) • 1924 • 3 MMBO; 0.3 BCF Buck Peak (Mancos, Nio) • 1956 • 4.7 MMBO; 8.2 BCF Puerto Chiquito (Mancos/Nio) • 1960 • 18.7 MMBO; 52 BCF Wattenberg (Nio, Codell) • 1980 • 86 MMBO, 1.1 Tcf Niobrara/Mancos Fields Silo (Niobrara) Rocky Mountain Region • 1981 • 10.4 MMBO; 8.2 BCF 5

Structure Niobrara 6

Modified from Meissner, 2004

Niobrara Wells

Drilling Info, 2020 Cretaceous: Derived from the Latin “creta” (chalk), usually abbreviated K for its German translation Kreide (chalk)

http://www2.nau.edu/rcb7/ ‘Unlock the Chalk’ Longman et al., 1998 Photo by Vince Matthews, 2017 Niobrara Formation

Longman et al., 1998

Upper Niobrara “A” Smoky Hill Hill Smoky Mbr.

Middle “B”

Lower “C”

Fort Hays

Kauffman & Caldwell, 1993 Barlow & Kauffman, 1985 Early Niobrara (Fort Hays) Time Middle Niobrara Time (Inoceramus erectus) (Scaphites depressus)

RMAG Atlas, 1972 Niobrara

Drilling Info, 2020 Niobrara Production PRB

100000 100000 100000 Cum (735 wells): 25,104,863 BO 112,563,986 MCF

10000 10000 10000 MCFD BWFD BOPD

1000 1000 1000

100 100 100 Daily Production Niobrara Horizontal Wells

Longbow, 2019 PRB – Resource Potential

EOG Resources 400,000 net acres 1600 drilling locations 2.4 billion barrels equivalent

Mowry 141,000 net acres 1.37 billion barrels equivalent

Niobrara 89,000 net acres 805 million barrels equivalent 17 Turner 169,000 net acres Chesapeake Energy owns 307,000 acres in the 300 million barrels equivalent Powder River Basin and has 2.7 billion barrels of oil equivalent gross recoverable resource potential. Amos Draw

Trabing

Area of Thermal Maturity

Anna, 2009 Salt Creek Teapot Overpressured Area 18 Structure Niobrara & Niobrara Producers Isopach Niobrara CI: 50ft. & Structure Niobrara CI: 1000ft. PowellPorcupine Todd

Niobrara A

Niobrara B

Niobrara C

Sage Breaks

Turner

Basal Turner Disconformity

Greenhorn

Frontier SS Turner SS (Deltaic HSST) (Shelf SS) Trabing

Crossbow

Salt Creek

Teapot

Purple Sage

Combs Ranch

Isopach Niobrara CI: 50ft. Isopach Niobrara C CI: 50ft. Isopach Carlile CI: 50 ft. Isopach Niobrara B CI: 50ft. Isopach Niobrara B CI: 50 ft. & Structure Niobrara CI: 1000 ft Isopach Niobrara A CI: 50ft. Facies Distribution

North South Nio B Structure Map State Wright N State Wright 3643-1D 3643-1D

Lakeside 1-H

Lakeside 1-H 1-12 JT Federal

Basin Axis 1-12 JT Federal

6 mi Facies 1. Lightly bioturbated marly chalk 2. Laminated pellet-rich 60 ft. 60 marl 3. Bioturbated pellet-rich 43 ft. 43 426 426 ft. marly chalk 4. Bioturbated pellet-rich marl 5. Interbedded to laminated to heavily bioturbated pellet-rich marl 6. Dark grey marl 7. Lightly bioturbated marly shale 8. Bioturbated marly shale Stewart, 2019 9. Lightly bioturbated shale 27 8032-52, Dark gray bioturbated to laminated marly shale

8076-94 Gray bioturbated, marly chalk

8052-76 Gray burrowed to laminated to massive marl, occasional oyster and inoceramid fragments

Niobrara Formation, Taylor, 2012 E = marly shale D2 = marl D1 = marly chalk

29 XRD Abraxas Lakeside 1-H

Niobrara Formation, Taylor, 2012 XRD Analysis

Niobrara Stratigraphy Facies

Most organic-rich interval Highest reservoir quality intervals 30 Classification of Mudrocks & Landing Zones XRF Analysis Detrital indicators Biogenic indicators Si, Al, Ti, K, Mn Ca, Sr, (Si)

Pierre Shale

Niobrara A bench

Niobrara B bench Marl

Chalk Marl

Niobrara C bench

Sage Breaks Shale

32 XRF Analysis Pseudo GR

Pierre Shale

Niobrara A bench (marl)

Marl Niobrara B bench

Chalk Marl

Niobrara C bench (marl)

Sage Breaks Shale

33 XRF Analysis Organic Productivity Anoxic Suite (Redox) Cr, Zn, Mo, V, Cu, Ni, U Mo, U, V Fe, S (pyrite)

Pierre Shale

Niobrara A bench

Niobrara B Marl bench

Chalk Marl

Niobrara C bench

Sage Breaks Shale 35 Abraxas Lakeside 1-H TOC by Facies (Taylor, 2012) 36

Niobrara Formation, Taylor, 2012 Niobrara Tmax Maturity Map

• Cuttings from Niobrara Formation • Least mature on western & eastern margins of basin • Most mature in southern PRB • Near basin axis • Tmax: ° - ° • Majority of production in Converse and

Niobrara Producers & Campbell counties Tmax Niobrara Formation (From USGS data base & Emre Kondaki, 2019) Structure Top Niobrara Highlighted contour = 8000 ft 38

Modified from Meissner, 2004 Parks and Gale, 1996 Regional Fractures Southern Powder River Basin

Predicted open fracture orientation based on fast shear-wave direction rotated from seismic line Shmax from borehole breakout

Predicted orientations Laubach, 1992

39 Boreholes oriented NNW- SSE

Lineament orientations Adapted from Parks and Gale, 1996 Fracture strike from FMS Significant Niobrara Wells

• EOG 3Q 2019 Highlight-Well: Niobrara Arbalest 473 -Record Well -IP30 1,250 Bopd, 250 Bpd NGLs, 4 MMcfdGas • Chesapeake Lebar 25-34-70 USA A NB 23H • Highest 80-day Niobrara cumulative oil production in basin’s history • IP of ~1,600 bo/d with strong deliverability • Peak Powder River Resources Briddle Bit Fed 2-11- 14NH • Niobrara C well • 1625 BOPD; 2588 MCFGD Estimate of generated volumes Niobrara Formation: > 60 billion barrels

Dashed dark blue outline is the Niobrara kitchen. Summary

• Large resource potential • Active targets: B and C Niobrara benches (most activity B bench) • Basal B bench chalky; upper B bench terrigenous dilution • Deposition in oxic and dysoxic conditions (Type II &III K) • Good TOC in B bench • Deep C scour into Sage Breaks (submarine) • C thick area = good development target area 42 • Recent wells targeting C bench • Overpressures • Regional fractures oriented N65o-70oE MUDTOC Consortium Sponsors - 2019

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