AAPG Bulletin, V. 82 (1998), No. 1 (January 1998), P. 25-49.

Implications of Outcrop Geology for Reservoirs in the Neogene Productive Series: Apsheron Peninsula, Azerbaijan¹

A. D. Reynolds,² M. D. Simmons,³ M. B. J. Bowman,² J. Henton,² A. C. Brayshaw,⁴ A. A. Ali-Zade,⁵ I. S. Guliyev,⁵ S. F. Suleymanova,⁵ E. Z. Ateava,⁵ D. N. Mamedova,⁵ and R. O. Koshkarly⁵

© Copyright 1998.  The American Association of Petroleum Geologists.  All Rights Reserved
 

¹Manuscript received March 13, 1996; revised manuscript received December 24, 1996; final acceptance July 23, 1997.
²BP Exploration, Building 200, Chertsey Road, Sunbury on Thames, Middlesex, TW16 7LN, United Kingdom.
³Department of Geology and Petroleum Geology, University of Aberdeen, King’s College, Aberdeen, AB24 3UE, United Kingdom.
⁴BP Exploration, P.O. Box 29335, Safat 13039, Kuwait.
⁵Geological Institute of the Azerbaijan Academy of Sciences, 29A Huseyn Cavid Prospect, Baku 370143, Azerbaijan.

This study forms part of the results of a cooperative project between the BP and Statoil Alliance and the Geological Institute of the Azerbaijan Academy of Sciences. We gratefully acknowledge the permission given by these entities to publish this work. We also are grateful for discussions and assistance in the field from T. Varney, S. Hall, and G. Geehan. We thank AAPG reviewers W. S. Hale-Erlich, A. L. Tchepalyga, and G. F. Ulmishek, and former AAPG Elected Editor K. T. Biddle for their helpful comments on the original draft of the manuscript. 

ABSTRACT

The Neogene sediments of eastern Azerbaijan and western Turkmenistan contain significant hydrocarbon reserves in deltaic reservoirs. Sedimentary logging of these reservoirs at outcrop in Azerbaijan has outlined four facies associations that encompass a range of paleoenvironments, from alluvial braided river sandstones and conglomerates to delta-front siltstones and mudstones. The facies associations suggest a river-dominated braid delta and are arranged into an architecture controlled by base-level changes: parasequences, parasequence sets, and sequence boundaries are key elements. The facies associations and stratigraphic architecture, together with outcrop observations of cementation and faulting, are summarized in terms of four idealized reservoir models: fluvial, delta plain, proximal delta front, and distal delta front. Each reservoir model has distinctive grain-size and shale distributions. Comparison of nearby oil fields with the studied outcrops suggests that the outcrops form good analogs from which to model reservoir architecture, barriers and baffles to fluid flow, reservoir heterogeneity, and reservoir quality variations.