Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas

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Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas. / Drits, Victor A.; Skibsted, Jorgen; Dorzhievava, Olga V.; Fallick, Anthony E.; Lindgreen, Holger.

In: American Mineralogist, Vol. 102, No. 7, 07.2017, p. 1402-1417.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Harvard

Drits, VA, Skibsted, J, Dorzhievava, OV, Fallick, AE & Lindgreen, H 2017, 'Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas', American Mineralogist, vol. 102, no. 7, pp. 1402-1417. https://doi.org/10.2138/am-2017-5992

APA

Drits, V. A., Skibsted, J., Dorzhievava, O. V., Fallick, A. E., & Lindgreen, H. (2017). Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas. American Mineralogist, 102(7), 1402-1417. https://doi.org/10.2138/am-2017-5992

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Author

Drits, Victor A. ; Skibsted, Jorgen ; Dorzhievava, Olga V. ; Fallick, Anthony E. ; Lindgreen, Holger. / Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas. In: American Mineralogist. 2017 ; Vol. 102, No. 7. pp. 1402-1417.

Bibtex

@article{7433592e85cb4885bdddbbc139c1deb7,
title = "Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas",
abstract = "A new type of quartz, a nano-quartz consisting of spherical particles, is assumed to have formed by crystallization in the sea during sedimentation of the chalk in the North Sea and to have remained largely intact during burial diagenesis. The presence and nature of this nano-quartz have not been identified until recently, despite the fact that this quartz is the type present in the Upper Cretaceous-Danian chalk reservoir for oil and gas in the North Sea, both in the flint and as dispersed particles. In the present work detailed structural analysis of the nano-quartz has been carried out by X-ray diffraction, solid-state Si-29 and Al-27 MAS NMR, thennal analysis including water release, IR-absorption spectroscopy, and elemental analysis supplemented with analysis of oxygen isotope composition. It is found that Al-IV substitutes for Si and that Al-VI probably is bonded to hydroxyls on the particle surface of the nano quartz structures. The charge compensation of tetrahedral Al3+, in addition to its conventional way of compensation by formation of the local structural arrangement [AlO4/M+](o) defects (M+ = H+, Na, K, Li), can occur at the expense of the Oft group coordinating one of the four tetrahedral Si4+ nearest to the Al3+ tetrahedron. The most significant feature of the North Sea nano-quartz deduced in the present investigation is the presence of [4H](Si) defects, also known as hydrogamet defects. This defect is present in up to 5% of the tetrahedral sites, whereas Al3+ occupies less than 1% of the tetrahedral sites. Two types of distribution of the [4H](Si) defects were determined. In one of them the [4H](Si) defects aggregates parallel to the (0001) plane to form platelets as cracks with hydroxylated surfaces on both sides. The second type of [4H](Si) defect occurs in the form of isolated tetrahedral vacant sites. The formation of the aggregated [4H](Si) platelets lying in the (0001) plane mostly increases the c parameters of the structure, whereas the isolated [4H](Si) defects and K+Na impurities contribute to increasing the a parameters. The remarkable correlation of the positional distribution of the samples revealed from the relationships between a and c parameters and between amount of OH- groups responsible for formation of [4H](Si) defects and a and c parameters can be considered as evidence for the validity of the structural formulas and, in general, of the main structural features of the studied samples. The unusually high content of [4H](Si) defects in the nano-quartz samples may be related to their formation by precipitation in waters of the Danish North Sea.",
keywords = "Nano-quartz structure, nano-quartz formation, hydrogarnet defects, X-ray diffraction, Al-27 and Si-29 MAS NMR, IR spectroscopy, thermal water release, delta O-18 isotope chemistry, elemental analysis, MAS NMR-SPECTROSCOPY, ALPHA-QUARTZ, SI-29 NMR, METAMORPHIC QUARTZ, CRYSTALLINE QUARTZ, LATTICE-CONSTANTS, NATURAL QUARTZ, DANIAN CHALK, OH-DEFECTS, WATER",
author = "Drits, {Victor A.} and Jorgen Skibsted and Dorzhievava, {Olga V.} and Fallick, {Anthony E.} and Holger Lindgreen",
year = "2017",
month = jul,
doi = "10.2138/am-2017-5992",
language = "English",
volume = "102",
pages = "1402--1417",
journal = "American Mineralogist",
issn = "0003-004X",
publisher = "Mineralogical Society of America",
number = "7",

}

RIS

TY - JOUR

T1 - Structural characterization of marine nano-quartz in chalk and flint from North Sea Tertiary chalk reservoirs for oil and gas

AU - Drits, Victor A.

AU - Skibsted, Jorgen

AU - Dorzhievava, Olga V.

AU - Fallick, Anthony E.

AU - Lindgreen, Holger

PY - 2017/7

Y1 - 2017/7

N2 - A new type of quartz, a nano-quartz consisting of spherical particles, is assumed to have formed by crystallization in the sea during sedimentation of the chalk in the North Sea and to have remained largely intact during burial diagenesis. The presence and nature of this nano-quartz have not been identified until recently, despite the fact that this quartz is the type present in the Upper Cretaceous-Danian chalk reservoir for oil and gas in the North Sea, both in the flint and as dispersed particles. In the present work detailed structural analysis of the nano-quartz has been carried out by X-ray diffraction, solid-state Si-29 and Al-27 MAS NMR, thennal analysis including water release, IR-absorption spectroscopy, and elemental analysis supplemented with analysis of oxygen isotope composition. It is found that Al-IV substitutes for Si and that Al-VI probably is bonded to hydroxyls on the particle surface of the nano quartz structures. The charge compensation of tetrahedral Al3+, in addition to its conventional way of compensation by formation of the local structural arrangement [AlO4/M+](o) defects (M+ = H+, Na, K, Li), can occur at the expense of the Oft group coordinating one of the four tetrahedral Si4+ nearest to the Al3+ tetrahedron. The most significant feature of the North Sea nano-quartz deduced in the present investigation is the presence of [4H](Si) defects, also known as hydrogamet defects. This defect is present in up to 5% of the tetrahedral sites, whereas Al3+ occupies less than 1% of the tetrahedral sites. Two types of distribution of the [4H](Si) defects were determined. In one of them the [4H](Si) defects aggregates parallel to the (0001) plane to form platelets as cracks with hydroxylated surfaces on both sides. The second type of [4H](Si) defect occurs in the form of isolated tetrahedral vacant sites. The formation of the aggregated [4H](Si) platelets lying in the (0001) plane mostly increases the c parameters of the structure, whereas the isolated [4H](Si) defects and K+Na impurities contribute to increasing the a parameters. The remarkable correlation of the positional distribution of the samples revealed from the relationships between a and c parameters and between amount of OH- groups responsible for formation of [4H](Si) defects and a and c parameters can be considered as evidence for the validity of the structural formulas and, in general, of the main structural features of the studied samples. The unusually high content of [4H](Si) defects in the nano-quartz samples may be related to their formation by precipitation in waters of the Danish North Sea.

AB - A new type of quartz, a nano-quartz consisting of spherical particles, is assumed to have formed by crystallization in the sea during sedimentation of the chalk in the North Sea and to have remained largely intact during burial diagenesis. The presence and nature of this nano-quartz have not been identified until recently, despite the fact that this quartz is the type present in the Upper Cretaceous-Danian chalk reservoir for oil and gas in the North Sea, both in the flint and as dispersed particles. In the present work detailed structural analysis of the nano-quartz has been carried out by X-ray diffraction, solid-state Si-29 and Al-27 MAS NMR, thennal analysis including water release, IR-absorption spectroscopy, and elemental analysis supplemented with analysis of oxygen isotope composition. It is found that Al-IV substitutes for Si and that Al-VI probably is bonded to hydroxyls on the particle surface of the nano quartz structures. The charge compensation of tetrahedral Al3+, in addition to its conventional way of compensation by formation of the local structural arrangement [AlO4/M+](o) defects (M+ = H+, Na, K, Li), can occur at the expense of the Oft group coordinating one of the four tetrahedral Si4+ nearest to the Al3+ tetrahedron. The most significant feature of the North Sea nano-quartz deduced in the present investigation is the presence of [4H](Si) defects, also known as hydrogamet defects. This defect is present in up to 5% of the tetrahedral sites, whereas Al3+ occupies less than 1% of the tetrahedral sites. Two types of distribution of the [4H](Si) defects were determined. In one of them the [4H](Si) defects aggregates parallel to the (0001) plane to form platelets as cracks with hydroxylated surfaces on both sides. The second type of [4H](Si) defect occurs in the form of isolated tetrahedral vacant sites. The formation of the aggregated [4H](Si) platelets lying in the (0001) plane mostly increases the c parameters of the structure, whereas the isolated [4H](Si) defects and K+Na impurities contribute to increasing the a parameters. The remarkable correlation of the positional distribution of the samples revealed from the relationships between a and c parameters and between amount of OH- groups responsible for formation of [4H](Si) defects and a and c parameters can be considered as evidence for the validity of the structural formulas and, in general, of the main structural features of the studied samples. The unusually high content of [4H](Si) defects in the nano-quartz samples may be related to their formation by precipitation in waters of the Danish North Sea.

KW - Nano-quartz structure

KW - nano-quartz formation

KW - hydrogarnet defects

KW - X-ray diffraction

KW - Al-27 and Si-29 MAS NMR

KW - IR spectroscopy

KW - thermal water release

KW - delta O-18 isotope chemistry

KW - elemental analysis

KW - MAS NMR-SPECTROSCOPY

KW - ALPHA-QUARTZ

KW - SI-29 NMR

KW - METAMORPHIC QUARTZ

KW - CRYSTALLINE QUARTZ

KW - LATTICE-CONSTANTS

KW - NATURAL QUARTZ

KW - DANIAN CHALK

KW - OH-DEFECTS

KW - WATER

U2 - 10.2138/am-2017-5992

DO - 10.2138/am-2017-5992

M3 - Journal article

VL - 102

SP - 1402

EP - 1417

JO - American Mineralogist

JF - American Mineralogist

SN - 0003-004X

IS - 7

ER -