Geophysical and transport properties of salt rocks during loading and exposed to dissolution (NERC Grant NE/X012751/1)
The dataset gather data from a dual experiment conducted to the study (i) the stress dependence of ultrasonic (elastic) waves and permeability of salt rocks, and (ii) the monitoring of controlled dissolution in an intact halite sample and a cracked (fractured) one. The tests were run in the high-pressure room-temperature (20°C) experimental setup for flow-through tests at the National Oceanography Centre, Southampton (NOCS) (Falcon et al. 2016). The rig consists of a triaxial vessel equipped with (i) ultrasonic sensors that allow measuring P- and S-wave velocities and their attenuation factors using the pulse echo method (McCann and Sothcott, 1992), and (ii) two rigs of electrodes embedded into the rubber sleeve of the pressure vessel for collecting electrical resistivity data that can be used to build up an electrical tomography of the sample (North el al. 2013). The rig has automatic control of both confining and pore pressure (ISCO EX-100D system). For the operating conditions and in homogeneous samples, the bulk electrical resistivity error is <1% for bulk resistivities <100 Ω m, increasing up to 5% with the degree of heterogeneity and above this resistivity value, at frequencies 1–500 Hz (North et al., 2013). Regarding the ultrasonic data, the technique and instrumentation used in this experiment provide velocity precision of ± 0.1% and accuracy of ± 0.3% (95% confidence), and attenuation accuracy of ± 0.1 dB cm-1 within the frequency range 300-1000 kHz (Best, 1992). The dataset presented here show the ultrasonic data at a single frequency of 600 kHz, obtained from Fourier analysis of broadband signals. Permeability to water and to N2 can be both determined with the aid of integrated flowmeters and pore pressure sensors both up- and downstream of the rock sample. The rock samples include: Pre-Cambrian salt (unknown well, Pakistan (source: www.likit.co.uk/)), Cambrian salt (unknown well, Tunguska Basin, Russia), Triassic salt (Arm Hill #1 well, NW Lancashire, UK), and Messinian salt (3A GN3 S02 well, core # 19, near Marianopoli, Sicily). 2.5 cm length, 5 cm diameter core plugs were extracted from precursor rocks, composition estimated by X-ray diffraction analysis, and connected porosity by He-pycnometry. Falcon-Suarez, I., North, L., Amalokwu, K., Best, A., 2016. Integrated geophysical and hydromechanical assessment for CO2 storage: shallow low permeable reservoir sandstones. Geophysical Prospecting 64, 828-847, http://doi.org/10.1111/1365-2478.12396. McCann, C., Sothcott, J., 1992. Laboratory measurements of the seismic properties of sedimentary rocks. Geological Society, London, Special Publications 65, 285-297, https://doi.org/10.1144/gsl.sp.1992.065.01.22. North, L., Best, A.I., Sothcott, J., MacGregor, L., 2013. Laboratory determination of the full electrical resistivity tensor of heterogeneous carbonate rocks at elevated pressures. Geophysical Prospecting 61, 458-470, https://doi.org/10.1111/j.1365-2478.2012.01113.x.
nonGeographicDataset
https://doi.org/10.5285/13c05fe8-0d1d-49e5-b55e-5cf4ef241c70
name: Digital Object Identifier (DOI)
function: information
https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item181881
name: Data
function: download
http://data.bgs.ac.uk/id/dataHolding/13608094
eng
geoscientificInformation
publication
2008-06-01
Underground storage
Dissolution
NGDC Deposited Data
Primary waves
Shear waves
Hydrogen
Rock salt deposits
Permeability
Ultrasonic tests
revision
2022
NERC_DDC
2022-05-15
2023-02-01
creation
2023-08-08
notApplicable
For the hydromechanical assessment: hydrostatic confining stress applied following the stress path: 5-10-5-15-5-20-5-30-5-50 MPa. Permeability to N2 and ultrasonic waves were measured at each stress, using the pore pressure transmission technique (e.g., Metwally and Sondergeld, 2011) For the dissolution tests: two samples were exposed to increasing pore pressure up to the constant confining pressure of 16 MPa, while the dissolution process was monitored with ultrasonic waves and electrical resistivity (i.e., decreasing effective stress). Water used for dissolution was a 3.5 wt.% NaCl brine solution Metwally, Y.M., Sondergeld, C.H., 2011. Measuring low permeabilities of gas-sands and shales using a pressure transmission technique. International Journal of Rock Mechanics and Mining Sciences 48, 1135-1144.
publication
2011
false
See the referenced specification
publication
2010-12-08
false
See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF
MS Excel
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National Oceanography Centre
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British Geological Survey
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British Geological Survey
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2025-01-18