Exceptional reservoir quality in HPHT reservoir settings: Examples from the Skagerrak Formation of the Heron Cluster, North Sea, UK

Abstract

(2016) 'Exceptional reservoir quality in HPHT reservoir settings : examples from the Skagerrak Formation of the Heron Cluster, UK, North Sea.', Marine and petroleum geology., 77 . pp. 198-215. Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. cementation and has had little to no effect on porosity preservation. The formation of welldeveloped authigenic chlorite (>70% surface coating) and, to a lesser extent illite clay coats with burial had a positive effect on porosity preservation even though permeability was marginally reduced in the illite-rich sandstones. A schematic porosity and quartz cement evolution model has been developed which allows for pre-drill prediction of reservoir quality in the Heron Cluster and provide valuable insights for other complex high-pressure hightemperature reservoirs.

Prediction of diagenetic facies using well logs – A case study from the upper Triassic Yanchang Formation, Ordos Basin, China

“…Similar with other works (Gluyas and Cade, 1997;Paxton et al, 2002;Stricker et al, 2016b), compaction is the predominant mechanism of porosity loss in this study, whereas cementation exerts much less important effects on reservoir quality.…”

The role played by carbonate cementation in controlling reservoir quality of the Triassic Skagerrak Formation, Norway

“…Previous studies attribute the exceptional reservoir porosities to chlorite coats (Stricker et al, 2016a;Stricker et al, 2016b;Taylor et al, 2015), overpressure (Grant et al, 2014;Nguyen et al, 2013;Stricker et al, 2016a;Stricker et al, 2016b), halite dissolution (Nguyen et al, 2013) and limiting time for quartz cement due to rapid burial (Maast, 2016). However, the occurrence of various carbonate cements within fluvial channel facies has been neglected.…”

“…9B). Chlorite coats in the Skagerrak Formation are intermediate according to the Fe/Mg-ratio (Stricker et al, 2016b), and show a wide grain coverage range from 1.3% to completely grain coating (100%) with an average of 48.0%. The thickness of the chlorite coats is generally less than 15 μm.…”

“…Other diagenetic minerals such as pyrite and K-feldspar overgrowths occur in negligible amounts (Stricker et al, 2016b;Taylor et al, 2015).…”

“…Ramm et al (1997) attributed anomalously high porosity to ubiquitous microquartz coatings in the Upper Jurassic reservoirs in the Norwegian Central Graben. Grant et al (2014) and Stricker et al (2016b) considered shallow onset of overpressure as an important control on the exceptional porosity in the Skagerrak Formations in the UK sector. In addition to overpressure, Nguyen et al…”