Wireline geophysical logging of the Nirex deep boreholes in the Sellafield area : comparisons between BVG core and wireline derived formation factors

Brereton, N.R.; Jackson, P.D.. 2003 Wireline geophysical logging of the Nirex deep boreholes in the Sellafield area : comparisons between BVG core and wireline derived formation factors. Nottingham, UK, British Geological Survey, 38pp. (CR/02/168N) (Unpublished)

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Abstract/Summary

The formation (resistivity) factor of a rock unit is a parameter based on electrical measurements that can be related directly to the porosity and, to a lesser degree, to the permeability. A reasonable correlation had previously been found between core sample and wireline derived formation factors for the Borrowdale Volcanic Group (BVG) in Nirex Borehole RCF3 in the Sellafield area (Brereton et al., 1996). It was concluded that wireline logs are able to provide an effective means of estimating the broad characteristics of formation factor variability with depth in a borehole and furthermore that they may be suitable for use in estimating the rock matrix diffusion properties of the in situ rock. The objective of the work reported here has been to further test this approach using core sample and wireline derived formation factors from other Nirex deep boreholes in the Sellafield area. For the purposes of calculating the wireline derived formation factors, the method used in Brereton et al., 1996 has been adopted in which the pore water resistivity in the BVG in the vicinity of any particular borehole has been taken to be constant. Values of pore water resistivity have been estimated from measurements on ground water produced from the Nirex boreholes and on pore water extracted from core samples. The wireline derived formation factors have then been compared with formation factor measurements made by the BGS on core samples during the Nirex Core Characterisation Programme.

Item Type:	Publication - Report
Programmes:	BGS Programmes > Other
Funders/Sponsors:	British Geological Survey, United Kingdom Nirex Limited
Additional Information. Not used in RCUK Gateway to Research.:	This item has been internally reviewed, but not externally peer-reviewed.
Date made live:	01 Oct 2024 15:35 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538138

Item Type:

Publication - Report

Programmes:

BGS Programmes > Other

Funders/Sponsors:

British Geological Survey, United Kingdom Nirex Limited

Additional Information. Not used in RCUK Gateway to Research.:

This item has been internally reviewed, but not externally peer-reviewed.

Date made live:

01 Oct 2024 15:35 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/538138