TY - JOUR
T1 - Characterising brines in deep mesozoic sandstone reservoirs, Denmark
AU - Holmslykke, Hanne D.
AU - Schovsbo, Niels H.
AU - Kristensen, Lars
AU - Weibel, Rikke
AU - Nielsen, Lars Henrik
N1 - Funding Information:
This contribution is part of the project GEOTHERM (“Geothermal energy from sedimentary reservoirs – Removing obstacles for large scale utilization”) (No. 615400011B) funded by the Innovation Fund Denmark (IFD). We thank the two reviewers, Ida Fabricius and Nicolas Marty, for their comments, which improved the manuscript.
PY - 2019/7/17
Y1 - 2019/7/17
N2 - The Danish subsurface contains several sandstone units, which represent a large geothermal resource (Vosgerau et al.
2016). Currently, only three geothermal plants are operating in
Denmark, but several exploration licences are expected to be awarded in
2019. Geothermal energy is exploited from deeply buried porous
sandstones by bringing warm formation water (brine) to the surface,
extracting the heat and returning the cooled water to the same
sandstones. The reduced temperature of the brine during this process
implies a risk of scaling, which may reduce reservoir permeability and
hence injectivity. Predicting the chemical composition of formation
waters, however, could help to reduce the risk associated with scaling
in planned geothermal facilities.
Here, we present a regional overview of the geochemistry of brines
from deep Mesozoic sandstones in the Danish Basin and North German Basin
that supplements previous studies, notably by Laier (2002, 2008). The
brine composition at shallow burial typically reflects the original
(connate) formation water chemistry, which is determined by the original
depositional environment of the sandstone, for example fluvial or
marine. However, the mineralogical composition of the sandstone changes
during burial, whereby some minerals may dissolve or precipitate when
exposed to higher temperatures. These mineral changes are reflected in
the brine composition, which typically becomes more saline with
increased burial (e.g. Laier 2008; Kharaka & Hanor 2003).
The brine chemistry reported here shows a distinct depth trend, which
reflects original connate formation waters that are modified through
burial diagenesis. We have classified the brines into brine types, which
are shown to be related to their depositional environment, depth,
geological formation and geographical domains.
AB - The Danish subsurface contains several sandstone units, which represent a large geothermal resource (Vosgerau et al.
2016). Currently, only three geothermal plants are operating in
Denmark, but several exploration licences are expected to be awarded in
2019. Geothermal energy is exploited from deeply buried porous
sandstones by bringing warm formation water (brine) to the surface,
extracting the heat and returning the cooled water to the same
sandstones. The reduced temperature of the brine during this process
implies a risk of scaling, which may reduce reservoir permeability and
hence injectivity. Predicting the chemical composition of formation
waters, however, could help to reduce the risk associated with scaling
in planned geothermal facilities.
Here, we present a regional overview of the geochemistry of brines
from deep Mesozoic sandstones in the Danish Basin and North German Basin
that supplements previous studies, notably by Laier (2002, 2008). The
brine composition at shallow burial typically reflects the original
(connate) formation water chemistry, which is determined by the original
depositional environment of the sandstone, for example fluvial or
marine. However, the mineralogical composition of the sandstone changes
during burial, whereby some minerals may dissolve or precipitate when
exposed to higher temperatures. These mineral changes are reflected in
the brine composition, which typically becomes more saline with
increased burial (e.g. Laier 2008; Kharaka & Hanor 2003).
The brine chemistry reported here shows a distinct depth trend, which
reflects original connate formation waters that are modified through
burial diagenesis. We have classified the brines into brine types, which
are shown to be related to their depositional environment, depth,
geological formation and geographical domains.
UR - http://www.scopus.com/inward/record.url?scp=85076966166&partnerID=8YFLogxK
U2 - 10.34194/GEUSB-201943-01-04
DO - 10.34194/GEUSB-201943-01-04
M3 - Article
VL - 43
JO - Geological Survey of Denmark and Greenland Bulletin
JF - Geological Survey of Denmark and Greenland Bulletin
SN - 1604-8156
M1 - e2019430104
ER -