EXPLORE The Depths of Our Experience

Stratigraphic, Lithologic, and Enrichment Character of the Mahogany Zone Oil Shale in the Eastern Uinta Basin, Utah International Oil Shale Symposium in Tallinn, Estonia June 10-13, 2013 Presented By: Steven B. Kerr Lindsay M. Schou Peter E. Doumit

3 Stratigraphic, Lithologic, and Enrichment Character of the Mahogany Zone Oil Shale in Eastern Utah

4 Green River Formation Basins

Uinta Basin Oil Shale Operations Regional Map 5

6 Regional Setting / Topography

7 Regional Stratigraphy Mahogany Zone

8 Historic Generalized Stratigraphy Mahogany Zone –Bracketed by A-Groove and B-Groove –Mahogany Marker and Mahogany Bed specifically identified Mahogany Zone

9 Mahogany Marker Ash-fall tuff ~0.2 m (0.5 ft) thick. Occurs ~1.5–3 m (5-10 ft) above the Mahogany Bed in lean oil shale. Very consistent and widespread-excellent for correlation.

Richest unit within MZ Prominent cliff-former 10 Mahogany Bed – m (8-15 ft thick) –Avg. ~200 lit/t (54 gal/t) –Easily identifiable in outcrop

11 Historic Drilling Map

12 Historical Drilling in the Uinta Basin ~ 300 holes define the Mahogany Zone along the east and southern portions of the Uinta Basin. Holes have been archived by UGS and USGS. –Most records include geology logs and assays. –~225 holes include down-hole geophysics.

Historical Drilling Data Benefits 13 The majority of the historical records have proven to be reliable. The records are useful in preliminary assessments of new areas. We are able to validate and use much of the historic data in our resource assessment models.

14 Regional Characteristics – MZ Thickness: Historical Data

15 Regional Characteristics – Average MZ Oil Grade: Historical Data

Historical Drilling Data Problems 16 Many records are not comprehensive and provide little data. Some of the data is of low quality and without much control. –Knowledge of the basin oil shale was minimal. –Marker beds often not identified. –Little QA/QC.

Historical Drilling Data Problems Cont. 17 Some of the data contains erroneous stratigraphic picks. –Base of the Mahogany Zone picked too early (False B-Groove). –Inconsistent stratigraphic tops picks between different geologists/companies. –Variable FA analysis intervals makes pick validation difficult. *** Use of erroneous/poor/limited data has led to historically inaccurate Mahogany Zone thicknesses and grades.

Norwest Data Synthesis 18 Re-evaluated Stratigraphic Picks –False Marker vs. Mahogany Marker –False B-Groove vs. B-Groove (Below Curly Tuff) –Consistent top picks based on density log signature. Fine-Tuned Assays –Eliminating potentially smeared (cuttings) or vague (>2 ft/sample) data Incorporation of Recent Drilling –~ 60 Core Holes

Uinta Basin Mahogany Zone Generalized Stratigraphy 19 Mahogany Zone –Thickness: m ( ft) –Avg. Richness: –95 lit/t (25 gal/t) Three Sisters: ~ 85 lit/t (22.5 gal/t) Three Brothers: ~ 96 lit/t (25.5 gal/t) Mahogany Bed: ~ 200 lit/t (54 gal/t) Middle MZ: ~ 114 lit/t (30 gal/t) Lower MZ: ~ 74 lit/t (19.5 gal/t)

Wavy Tuff Lower R-8 Zone Middle R-8 Zone Three Sisters A-Groove Three Brothers Upper Mahogany Zone Mahogany Bed Middle Mahogany Zone False B Lower Mahogany Zone Curly Tuff B-Groove Wavy Tuff Lower R-8 Zone Middle R-8 Zone Three Sisters A-Groove Three Brothers Upper Mahogany Zone Mahogany Bed Middle Mahogany Zone False B-Groove Lower Mahogany Zone Curly Tuff B-Groove

Uinta Basin Mahogany Zone Geophysical Response 21

Synthesis of Data – MZ Thickness: Historical vs. Combined Data 22

23 Synthesis of Data – FA Grade: Historical vs. Combined Data

Summary 24 Historic Generality / Recent Specificity Stratigraphic Details –Recognize the full package –Correlate the density profile New models with corrected historic data and inclusion of recent data reflect the most accurate knowledge of the Uinta Basin’s Mahogany Zone character to date.

Acknowledgements 25

26 EXPLORE the Depths of our Experience Norwest Corporation