Siderite occurrence in petroleum systems and its potential as a hydrocarbon-migration proxy: A case study of the Catcher Area Development and the Bittern area, UK North Sea

Abdulkarim, Maryam A. ¹Muxworthy, Adrian R. ¹Fraser, Alastair ¹Neumaier, Martin ¹Hu, Pengxiang ²Cowan, Alison¹

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作者信息

1. Imperial Coll
2. Australian Natl Univ
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Abstract

We report a detailed magnetic study of Tertiary sandstone cores from the Bittern field, West Central Graben, and Catcher Area Development (CAD), West Central Shelf, UK North Sea that identified siderite as a potential magnetic proxy for the differentiation of vertical and lateral hydrocarbon migration. Magnetic hysteresis experiments revealed increased presence of paramagnetic minerals in the oil-stained sandstones of the fields compared to the nearby dry Tertiary (unstained) sandstone of offset wells. Within the oil-stained sandstones, the paramagnetic proportion is highly variant, with low and high paramagnetic sections present. Detailed experiments including thermomagnetometry between 10 K and 900 K and XRD analysis, combined with Mo & BULL;ssbauer spectroscopy confirmed that this increase in paramagnetic response was primarily due to the formation of siderite. An increase in the quantity of paramagnetic clays and occasionally pyrite also contributed to the increased response. Siderite and iron sulphides have been interpreted to form during hydrocarbon migration and potentially oil biodegradation. We propose that hydrocarbon migration pathways may be indicated by the distribution of siderite. We argue that as hydrocarbons migrate vertically and the equilibrium partial pressure of CO2 with the environment reduces, essential HCO3- is produced which reacts with available Fe2+ to form siderite if all the other diagenetic requirements for its formation are met. The distribution of siderite and magnetic susceptibility values along the oil-stained layer provides a tool for the determination of the migration pathways in low sulphur hydrocarbon environments containing reactive iron.

Key words

Mineral magnetism/Siderite in hydrocarbon reservoirs/Hydrocarbon migration/Magnetic susceptibility/Diagenesis/UK Central North Sea/CARBON-DIOXIDE/MAGNETIC-PROPERTIES/BRENT-GROUP/OIL/WATER/BIODEGRADATION/RESERVOIRS/TEMPERATURE/DIAGENESIS/SANDSTONE

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出版年

2022

Journal of Petroleum Science & Engineering

ISSN：0920-4105

被引量2

参考文献量66

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