In situ electrical conductivity measurements of H 2 O under static pressure up to 28 GPa

2016 ◽  
Vol 380 (37) ◽  
pp. 2979-2983 ◽  
Author(s):  
Bao Liu ◽  
Yang Gao ◽  
Yonghao Han ◽  
Yanzhang Ma ◽  
Chunxiao Gao
Keyword(s):  
Electrical Conductivity ◽  
Static Pressure ◽  
Conductivity Measurements

scholarly journals Blocking borehole conductivity logs at the resolution of above-ground electromagnetic systems

Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. E67-E77 ◽  
Author(s):  
Aaron Davis ◽  
Juerg Hauser
Keyword(s):  
Electrical Conductivity ◽  
Ground Truth ◽  
Earth Structure ◽  
Conductivity Measurements ◽  
Noise Levels ◽  
Survey Line ◽  
Number Of Segments ◽  
Borehole Log ◽  
System Geometry

Borehole conductivity logs provide an in situ measurement of the electrical conductivity of the subsurface. Despite the measurements being a proxy for the true earth structure, they are often used as ground truth when inferring subsurface electrical conductivity boundaries between lithologies. Borehole conductivity measurements are therefore commonly used to plan and benchmark electromagnetic (EM) surveys and to establish the credibility of a given inversion technique. A consequence of the diffusion physics of EM prospecting is that not all subsurface features present in a conductivity log can be resolved by an EM system, nor can they be recovered by a subsequent inversion. Quantification of the ability of an EM system to determine layer boundaries in the subsurface is therefore an issue meriting investigation. We have developed a reversible-jump Markov chain Monte Carlo (RJMCMC) method to segment borehole conductivity logs at the scale recoverable by a given EM system as the foundation for an objective comparison between the inversion results and conductivity logs. A common consequence of RJMCMC inversions for EM problems is that few layers are required to fit the data. Similarly, we find that a borehole log blocked at the scale sensed by an EM system consists of a limited number of segments. Segmentation of borehole conductivity logs is determined by the physics of EM prospecting and by factors such as base frequency, number of gates, system geometry, and noise levels. For a survey line intersecting a borehole near Carnarvon, Western Australia, we see that different inversion schemes result in images of the subsurface that are consistent with a borehole conductivity log segmented according to the mechanics of the EM system and accounting for the physics of EM prospecting.

scholarly journals Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Geeth Manthilake ◽  
Mainak Mookherjee ◽  
Nobuyoshi Miyajima
Keyword(s):  
Electrical Conductivity ◽  
Subduction Zones ◽  
High Pressures ◽  
High Electrical Conductivity ◽  
Conductivity Measurements ◽  
Forming Mechanism ◽  
Geophysical Processes ◽  
High Pressures And Temperatures ◽  
Subducting Slab

AbstractThe dehydration and decarbonation in the subducting slab are intricately related and the knowledge of the physical properties of the resulting C–H–O fluid is crucial to interpret the petrological, geochemical, and geophysical processes associated with subduction zones. In this study, we investigate the C–H–O fluid released during the progressive devolatilization of carbonate-bearing serpentine-polymorph chrysotile, with in situ electrical conductivity measurements at high pressures and temperatures. The C–H–O fluid produced by carbonated chrysotile exhibits high electrical conductivity compared to carbon-free aqueous fluids and can be an excellent indicator of the migration of carbon in subduction zones. The crystallization of diamond and graphite indicates that the oxidized C–H–O fluids are responsible for the recycling of carbon in the wedge mantle. The carbonate and chrysotile bearing assemblages stabilize dolomite during the devolatilization process. This unique dolomite forming mechanism in chrysotile in subduction slabs may facilitate the transport of carbon into the deep mantle.

Rock matrix diffusivity determinations by in-situ electrical conductivity measurements

2001 ◽  
Vol 47 (2-4) ◽  
pp. 117-125 ◽  
Author(s):  
Yvonne Ohlsson ◽  
Martin Löfgren ◽  
Ivars Neretnieks
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Measurements ◽  
Rock Matrix

CO2 decomposition kinetics of YBa2Cu3O7−x via in situ electrical conductivity measurements

1991 ◽  
Vol 6 (7) ◽  
pp. 1393-1397 ◽  
Author(s):  
E.A. Cooper ◽  
A.K. Gangopadhyay ◽  
T.O. Mason ◽  
U. Balachandran
Keyword(s):  
Electrical Conductivity ◽  
Volume Fraction ◽  
Conductivity Measurements ◽  
Impedance Measurements ◽  
Kinetics Of Decomposition ◽  
Rapid Formation ◽  
Kinetics Of ◽  
Gradual Decay ◽  
Co2 Decomposition

In situ electrical conductivity measurements were employed to study the kinetics of decomposition of YBa2Cu3O7−x in flowing 5% CO2/95% O2 atmosphere at 815 °C. Three regimes could be observed in the decay of the conductivity with time, interpreted as corresponding to nucleation over the initial 5–10 min, rapid formation of Y2Cu2O5, BaCO3, and CuO between 10 min and 1 h, and finally transition to the formation of Y2BaCuO5, BaCO3, and CuO at longer times. The absence of dispersion in impedance measurements as a function of frequency together with the gradual decay of conductivity (roughly corresponding to the remaining volume fraction of YBa2Cu3O7−x) indicates that not all grain boundaries are involved in the decomposition process.

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