Assessment of undiscovered conventional oil and gas resources of North Africa, 2012

World Petroleum Resources Project

Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 19 billion barrels of technically recoverable undiscovered conventional oil and 370 trillion cubic feet of undiscovered conventional natural gas resources in 8 geologic provinces of North Africa.

Introduction

The U.S. Geological Survey (USGS) assessed the potential for undiscovered conventional oil and gas accumulations within priority geologic provinces of North Africa as part of the USGS World Petroleum Resources Project. Eight priority geologic provinces were assessed in this study, which represents a reassessment of North Africa last published in 2000 (U.S. Geological Survey World Energy Assessment Team, 2000). The eight geologic provinces include (1) Nile Delta Basin; (2) Sirte Basin; (3) Pelagian Basin; (4) Trias/Ghadames Basin; (5) Hamra Basin; (6) Illizi Basin; (7) Grand Erg/Ahnet Basin; and (8) Essaouira Basin (fig. 1). Resource estimates for the Nile Delta, Sirte, and Pelagian Basin provinces were published previously (Kirschbaum and others, 2010; Whidden and others, 2011), but are included here for a more complete view of undiscovered conventional oil and gas resources across North Africa.

Figure 1. Locations of eight priority geologic provinces of North Africa assessed in this study of undiscovered conventional oil and gas resources.

The assessment methodology included a complete geologic framework description for each province based mainly on published literature and definitions of petroleum systems and assessment units (AU) within these systems. Exploration and discovery history data were a critical part of the methodology used to estimate sizes and numbers of undiscovered conventional accumulations. Each AU was assessed for undiscovered oil and nonassociated gas accumulations, and co-product ratios were used to calculate the volumes of associated gas (gas in oil fields) and volumes of natural gas liquids.

Resource Summary

The USGS assessed undiscovered conventional oil and gas resources in 18 AUs within eight geologic provinces, with the following estimated mean totals: (1) for conventional oil resources, 18,618 million barrels of oil (MMBO), with a range from 6,846 to 37,460 MMBO; (2) for undiscovered conventional gas, 370,375 billion cubic feet of gas (BCFG), with a range from 149,541 to 712,430 BCFG; and (3) for natural gas liquids (NGL), 12,553 MMBNGL, with a range from 4,809 to 24,785 MMBNGL.

Of the mean undiscovered conventional oil resource of 18,618 MMBO, about 41 percent (7,557 MMBO) is estimated to be in the Offshore Salt Structures AU, offshore Morocco. Other significant AUs for potential undiscovered oil include the Offshore Sirte Basin AU (2,267 MMBO), Onshore Sirte Carbonate-Clastic AU (1,278 MMBO), and the Berkine Paleozoic and Mesozoic Reservoirs AU (1,839 MMBO) of the Trias/ Ghadames Basin. Of the mean undiscovered gas resource of 370,375 BCFG, about 59 percent (217,313 BCFG) is estimated to be in the Nile Cone AU. Other significant AUs for potential undiscovered gas resources include the Offshore Salt Structures AU of Morocco (45,208 BCFG), the Offshore Sirte Basin AU (22,637 BCFG), and the Gourara Paleozoic Reservoirs AU (15,559 BCFG) of the Grand Erg/Ahnet Basin Province. These four AUs encompass about 81 percent of the undiscovered gas resource.

Table 1. Assessment results for undiscovered conventional oil and gas resources for provinces of North Africa. [MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. For gas accumulations, all liquids are included as NGL (natural gas liquids) category. Undiscovered gas resources are the sum of nonassociated (gas in gas fields) and associated gas (gas in oil fields). F95 represents a 95 percent chance of at least the amount tabulated–other fractiles are defined similarly. Fractiles are additive under the assump- tion of perfect positive correlation. Shading indicates not applicable]

References Cited

Kirschbaum, M.A., Schenk, C.J., Charpentier, R.R., Klett, T.R., Brownfield, M.E., Pitman, J.K., Cook, T.A., and Tennyson, M.E., 2010, Assessment of undiscovered oil and gas resources of the Nile Delta Province, Eastern Mediterranean: U.S. Geological Survey Fact Sheet FS 2010–3027, 4 p.

U.S. Geological Survey World Energy Assessment Team, 2000, U.S. Geological Survey World Petroleum Assessment 2000— Description and results: U.S. Geological Survey Digital Data Series DDS-60, 4 CD–ROMs.

Whidden, K.J., Lewan, M.D., Schenk, C.J., Charpentier, R.R., Cook, T.A., Klett, T.R., and Pitman, J.K., 2011, Assessment of undiscovered oil and gas resources of Libya and Tunisia, 2010: U.S. Geological Survey Fact Sheet FS 2011–3105, 2 p.

Photo by K.J. Whidden, 2005.

For Further Information

Supporting studies of the geologic models and the methodology used in the assessment of North African provinces are in progress. Assessment results are available at the USGS Energy Program Web site, http://energy.cr.usgs.gov/oilgas/.

North Africa Provinces Assessment Team:

Christopher J. Schenk, Timothy R. Klett, Katherine J. Whidden, Mark A. Kirschbaum, Ronald R. Charpentier, Troy A. Cook, Michael E. Brownfield, and Janet K. Pitman.

Where this page came from

This page was imported from U.S. Geological Survey. Published by the U.S. Geological Survey and, as a work of the United States government, in the public domain.

Nobody has written it yet — it is the source material at a new address, which is why search engines are asked to skip it and why no one earns from it. It is up for grabs: take it on, and it is yours to rewrite and to earn from.