A megascale view of reservoir quality in producing sandstones from the offshore Gulf of Mexico

Ehrenberg, S. N.; Nadeau, Paul; Steen, Øyvind

doi:10.1306/09280707062

Cited by 55 publications

(33 citation statements)

References 29 publications

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“…Porosity loss in sandstones can be generally predicted to some degree of accuracy giving rise to regional porosity-depth or porosity-temperature curves for many hydrocarbon basins (e.g. Ehrenberg et al, 2008). However, occurrences of sandstone reservoirs with higher than expected porosity are commonly attributed to conditions that limit the degree of burial compaction and/or cementation, or to pre-existing cements and grain coatings (e.g.…”

Section: Introductionmentioning

confidence: 99%

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

Stricker

Jones

Sathar

et al. 2016

Marine and Petroleum Geology

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(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.

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Section: Introductionmentioning

confidence: 99%

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

Stricker

Jones

Sathar

et al. 2016

Marine and Petroleum Geology

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“…Reservoirs with anomalously high porosities are common in several hydrocarbon basins, e.g. Central Graben, North Sea, UK (Osborne & Swarbrick 1999;Nguyen et al 2013;Grant et al 2014); the Gulf of Mexico, USA (Taylor et al 2004;Ehrenberg et al 2008;; the Santos Basin, Brazil (Anjos et al 2003) and the Indus Basin, Pakistan (Berger et al 2009). Current understanding of porosity preservation in deeply buried sandstone reservoirs (.4000 mbsf, metres below sea floor) tends to be focused on how coatings of clay and microquartz on detrital grains can inhibit macroquartz cementation.…”

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confidence: 99%

Enhanced porosity preservation by pore fluid overpressure and chlorite grain coatings in the Triassic Skagerrak, Central Graben, North Sea, UK

Stricker¹,

Jones²

2016

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Current understanding of porosity preservation in deeply buried sandstone reservoirs tends to be focused on how diagenetic grain coatings of clay minerals and microquartz can inhibit macroquartz cementation. However, the importance of overpressure developed during initial (shallow) burial in maintaining high primary porosity during subsequent burial has generally not been appreciated. Where pore fluid pressures are high, and the vertical effective stress is low, the shallow arrest of compaction can allow preservation of high porosity and permeability at depths normally considered uneconomic. The deeply buried fluvial sandstone reservoirs of the Triassic Skagerrak Formation in the Central Graben, North Sea, show anomalously high porosities at depths greater than 3500 metres below sea floor (mbsf). Pore pressures can exceed 80 MPa in the upper part of the Skagerrak Formation at depths of 4000-5000 mbsf, where temperatures are above 1408C. The Skagerrak reservoirs commonly have high primary porosities of up to 35%, little macroquartz cement and variable amounts of diagenetic chlorite grain coats. This research sheds light on the complex controls on reservoir quality in the fluvial sandstones of the Skagerrak Formation by identifying the role of shallow overpressure in arresting mechanical compaction and the importance of chlorite detrital grain coatings in inhibiting macroquartz cement overgrowth as temperature increases during progressive burial.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.

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“…12, No. 1; mineralogy according to Folk andDott classifications (Folk, 1980 andDott, 1964) provides information that the formation under this study covers sublitharenite followed by litharenite, quartzarenite, subarkose, lithic greywacke, and feldspathic litharenite.…”

Section: Data and Integrated Thin Section Petrography And Sem Descripmentioning

confidence: 97%

Connecting Microscopic Geological Features to Pore Geometry and Pore Structure: Case Study - Sandstone Reservoir of Balikpapan Formation, Kutai Basin

Musu¹,

Permadi²,

Widarsono³

2017

MAS

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Understanding geological features with engineering aspect has been done by previous studies and remains attractive by both geologists and engineers. This study employed data of a total of one hundred and seventy-nine (179) sandstone samples obtained from the Middle Miocene to Late Miocene Balikpapan Formation in Kutai Basin, Indonesia. The data includes thin section porosity, scanning electron microscope (SEM), x-ray diffraction (XRD), and capillary pressure (Pc). All samples are mainly dominated by quartz with additional rock fragment and feldspar, and additional component such as plagioclase, heavy minerals, occasional carbonaceous materials, micas and opaque minerals. Detrital clays, pseudomatrix and laminated clays occurred locally in minor quantity. Porosity ranges from 6 to 28.8.9%, whereas permeability ranging from 0.02 and 4,718 mD. This study investigates the relationship of microscopic geological features with pore geometry and pore structures. Kozeny equation and Leverette's J-Function are implemented to characterize the pore geometry and structure in correlation with microscopic geologic features. The main findings of the study are that: i) combination of quartz content, texture, clay content, and the diagenetic history of quartz cementation strongly relates to both pore geometry and structure of the sandstone samples, ii) the content of cements does not show a systematic effect on either pore geometry or pore structure, and iii) in general, for all the sandstone samples employed here, the higher quartz and lower clay contents tend to give both a larger pore geometry and lower pore structure in terms of pore tortuosity.

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A megascale view of reservoir quality in producing sandstones from the offshore Gulf of Mexico

Cited by 55 publications

References 29 publications

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

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

Enhanced porosity preservation by pore fluid overpressure and chlorite grain coatings in the Triassic Skagerrak, Central Graben, North Sea, UK

Connecting Microscopic Geological Features to Pore Geometry and Pore Structure: Case Study - Sandstone Reservoir of Balikpapan Formation, Kutai Basin

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