About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 105, No. 10 (October 2021), P. 1973-1991.

Copyright ©2021. The American Association of Petroleum Geologists. All rights reserved.

DOI: 10.1306/07062019207

Identification of magnetic enhancement at hydrocarbon-fluid contacts

Sijibomioluwa A. Badejo,1 Adrian R. Muxworthy,2 Alastair Fraser,3 Graham R. Stevenson,4 Xiang Zhao,5 and Michael Jackson6

1Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; present address: CGG, Tyn Y Coed, Llanrhos, Llandudno, United Kingdom; [email protected]
2Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; [email protected]
3Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; [email protected]
4Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; [email protected]
5Research School of Earth Sciences, Australian National University, Canberra, Australia; [email protected] edu.au
6Institute for Rock Magnetism (IRM), University of Minnesota, Minneapolis, Minnesota; [email protected]

ABSTRACT

Identifying the depths of the hydrocarbon-fluid contacts in a reservoir is important for determining hydrocarbon reserves and production planning. Using core samples from the Tay Sandstone reservoir in the central North Sea, we show that there is a magnetic enhancement at the hydrocarbon-fluid contacts that is detectable through both magnetic susceptibility measurements and magnetic hysteresis measurements. We observed this magnetic enhancement at both gas-oil and oil-water contacts, which have been independently identified using nonmagnetic methods; we did not consider gas-water contacts in this study. We demonstrate that this magnetic enhancement is caused by the precipitation of new nanometric iron oxide (magnetite) and iron sulfide (greigite) phases. The magnetic enhancement may be caused by diagenetic changes or preferential biodegradation at the top of the oil column during early filling and at the oil-water contact. Our findings have the potential to be used to identify paleo-hydrocarbon-fluid contact in both structurally modified fields and failed wells. The technique can also be used to infer the fill history of a basin and calibrate petroleum systems models. Magnetic susceptibility measurements have the advantage that they can easily and quickly be measured in the field on whole core material.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].