Brookian Sequence Well Log Correlation Sections and Occurrence of Gas Hydrates, North-Central North Slope, Alaska Nor t h P a cific O cean Ber i n g S e a O kho t s k Sea UNITED STATES Alaska CHINA CANADA A r ctic H u dso n O cean Bay RUSSIA Svalbard GREENLAND B a r e n t s KAZAKHSTAN Sea ICELAND Nor t h Atlan tic O cea n Baltic Sea Scientific Investigations Report 2013–5050 U.S. Department of the Interior U.S. Geological Survey COVER. Part of the Alaska Mount Elbert Stratigraphic Test Well project in 2007 (photo taken by Timothy S. Collett). Brookian Sequence Well Log Correlation Sections and Occurrence of Gas Hydrates, North-Central North Slope, Alaska By Kristen A. Lewis and Timothy S. Collett Scientific Investigations Report 2013–5050 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2013 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Lewis, K.A., and Collett, T.S., 2013, Brookian sequence well log correlation sections and occurrence of gas hydrates, north-central North Slope, Alaska: U.S. Geological Survey Scientific Investigations Report 2013–5050, 23 p., http:// pubs.usgs.gov/sir/2013/5050/. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................1 1 Gas Hydrate Properties.................................................................................................................................2 1 Controls on Gas Hydrate Formation ............................................................................................................4 .................................................................................................................................2 Gas Hydrate Stability Conditions ........................................................................................................4 ............................................................................................................4 Availability of Gas and Water .............................................................................................................5 ........................................................................................................4 Availability of Gas and Water Migration Pathways ........................................................................5 .............................................................................................................5 Availability of Reservoir Sediments and Seals ................................................................................6 ........................................................................5 Permafrost-Associated Gas Hydrate Accumulations ....................................................................6 ................................................................................6 Geologic Setting of the Alaska North Slope ..............................................................................................7 ....................................................................6 Stratigraphic Framework of Well Sections .............................................................................................10 ..............................................................................................7 Gas Hydrate Stability Conditions of the Alaska North Slope ................................................................14 .............................................................................................10 Gas Hydrates of the Alaska North Slope .................................................................................................15 ................................................................14 Well Log Detection of Gas Hydrates .........................................................................................................19 .................................................................................................15 Assessments of the Alaska North Slope Gas Hydrates ........................................................................20 .........................................................................................................19 Summary........................................................................................................................................................21 ........................................................................20 References Cited..........................................................................................................................................21 21 21 Figures 1. Locations of known (purple diamonds) and inferred (red circles) gas hydrate occurrences throughout the world ....................................................................................2 2. Well log correlation section line 1 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 1 through 11 .......................................................................................................................... link 3. Well log correlation section line 2 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 1 and 12 through 24 ..................................................................................................................... link 4. Well log correlation section line 3 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 25 through 33 .......................................................................................................................... link 5. Well log correlation section line 4 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 34 through 54 .................................................................................................... link 6. Well log correlation section line 5 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 55 through 71 .......................................................................................................................... link iv 7. Well log correlation section line 6 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 72 through 93 .......................................................................................................................... link 8. Well log correlation section line 7 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 94 through 107 ........................................................................................................................ link 9. Well log correlation section line 8 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 108 through 114 ........................................................................................................................ link 10. Well log correlation section line 9 showing well log markers (C-horizons), gas hydrate picks, gas hydrate stability zone, base of ice-bearing permafrost picks, and 0 °C markers for wells with map identification numbers 115 through 122 ........................................................................................................................ link 11. Map of central North Slope showing study wells (green dots), producing oil fields (yellow polygons), known gas hydrate accumulations (orange dashed line), free gas accumulations (green dashed line), and lines of well log correlation sections (red solid lines) in figures 2–10 .............................................................................3 12. Gas hydrate phase diagram showing depth and temperature conditions suitable for gas hydrate formation for various