Skip to Main Content
Book Chapter

A Failed Hydrocarbon System—Rawson Basins, Argentina

By
Robert M. Otis
Robert M. Otis
Chevron Overseas Petroleum, Inc. San Ramon California, U.S.A.
Search for other works by this author on:
Nahum Schneidermann
Nahum Schneidermann
Chevron Overseas Petroleum, Inc. San Ramon California, U.S.A.
Search for other works by this author on:
Published:
January 01, 2000

Abstract

The business environment of the petroleum industry over the past 10 years has exerted increasing pressure on companies to improve exploration success with a corresponding reduction in costs and cycle time. Companies have responded by establishing processes for geologic risk assessment, volumetric estimation, and economic analysis. The ‘hydrocarbon system’ concept is integral to all of these processes because it focuses evaluation drilling programs to address fundamental uncertainties of the petroleum geology. In this manner, companies can significantly cut the cycle time to key decisions, move quickly into appraisal or to other opportunities, and thereby reduce costs and allow evaluation of additional prospective areas.

The hydrocarbon system concept was used in a frontier exploration program in the Rawson Basins, offshore Argentina. The focus of the postulated play was a test designed to prove or disprove the presence of a hydrocarbon system in any of the basins, rather than the more classic approach of testing the most economically viable (i.e., largest) prospect. The exploration program commenced with acquisition and interpretation of seismic and potential field data. A geologic model was developed assuming a hydrocarbon system composed of a lacustrine source rock associated with early rifting of the Atlantic Ocean, interbedded shales and fluvial–deltaic sandstones for seal and reservoir rocks, and structural closures for trap. An evaluation drilling program was developed to test the presence of an active hydrocarbon, and a single obligation well was positioned to test for a lacustrine source rock in the basin center, migration pathways, and reservoir and seal. Drilling encountered a sequence of red beds that lacked discrete reservoir sandstones or organic shales. The well penetrated the ‘basement’ Paleozoic strata and was abandoned without any drill-stem testing.

The absence of a hydrocarbon system was clear, and the decision to abandon the area was validated. The appraisal of the Rawson Basins was done quickly, had clear objectives for evaluation (to prove or disprove the hydrocarbon system), and resulted in a sound and timely decision, based on clear, definitive data, to pursue other opportunities elsewhere.

You do not currently have access to this article.

Figures & Tables

Contents

AAPG Memoir

Petroleum Systems of South Atlantic Margins

Marcio Rocha Mello
Marcio Rocha Mello
Search for other works by this author on:
Barry J. Katz
Barry J. Katz
Search for other works by this author on:
American Association of Petroleum Geologists
Volume
73
ISBN electronic:
9781629810706
Publication date:
January 01, 2000

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal