Skip to Main Content
Book Chapter

Petroleum Systems of the Ogooué Delta, Offshore Gabon

By
B.J. Katz
B.J. Katz
Texaco Inc. Upstream Technology Department Houston, Texas, U.S.A.
Search for other works by this author on:
W.C. Dawson
W.C. Dawson
Texaco Inc. Upstream Technology Department Houston, Texas, U.S.A.
Search for other works by this author on:
L.M. Liro
L.M. Liro
Texaco Inc. International Exploration Department Bellaire, Texas, U.S.A.
Search for other works by this author on:
V.D. Robison
V.D. Robison
Texaco Inc. International Exploration Department Bellaire, Texas, U.S.A.
Search for other works by this author on:
J.D. Stonebraker (Retired)
J.D. Stonebraker (Retired)
Texaco Inc. International Exploration Department Bellaire, Texas, U.S.A.
Search for other works by this author on:
Published:
January 01, 2000

Abstract

An analysis of the petroleum geology of the Ogooué Delta region reveals the presence of two independent petroleum systems: the Madiela/Cap Lopez–Batanaga(.) and the Azile/Anguille–Anguille(!) systems. An independent system is defined as a suite of hydrocarbon accumulations that share a common source and reservoir couplet. The oils in the first system appear to have been generated from a pre-Cenomanian restricted (elevated salinity) marine source. These oils occur largely in Batanga Formation sandstones (Maestrichtian) and are limited mainly to the southern parts of the delta. The petroleum in the second system appears to have been generated from the Azile and Anguille Formations (Senonian) and thus developed under more normal marine conditions. This second group of oils is mainly found in Anguille reservoirs, which were deposited in submarine fans during lowstand events. This second system is geographically less restricted, being present in both the northern and southern parts of the delta.

The geographic distribution of the two systems is controlled by several factors, including the distribution of the source, the nature of the migration network, and the level of thermal maturity. Both systems share one major controlling factor: the areal limit of the two systems is in part constrained by thermal maturation. The overburden associated with the delta complex provided for appropriate levels of thermal maturation for generation to proceed. Modeling results suggest that the pre-Cenomanian marine shales and marls began generating liquid hydrocarbons during the Oligocene. The Senonian system began generating hydrocarbons during the Miocene. Both systems are still actively generating as subsidence and loading continues. The pre-Cenomanian system appears to have a more effective mechanism for vertical migration than the Azile–Anguille sourced system. This greater efficiency explains the younger age for the dominant reservoir of the pre-Cenomanian (older) system. It appears that the southward shift in the delta's depocenter may be a partial explanation for this greater efficiency.

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