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Registro de conductividad eléctrica en el flujo del fluido de un pozo profundo durante y después de la perforación : estimación de trasmisividad, salinidad del agua y carga hidráulica de las zonas conductivas

Doughty, Christine; Tsang, Chin Fu; Rosberg, Jan Erik LU ; Juhlin, Christopher; Dobson, Patrick F. and Birkholzer, Jens T. (2017) In Hydrogeology Journal 25(2). p.501-517
Abstract

Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better... (More)

Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

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author
organization
alternative title
Flowing fluid electrical conductivity logging of a deep borehole during and following drilling : estimation of transmissivity, water salinity and hydraulic head of conductive zones
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Drilling, Fractured rock, Hydraulic head, Hydraulic testing, Well logging
in
Hydrogeology Journal
volume
25
issue
2
pages
17 pages
publisher
Springer
external identifiers
  • scopus:85000443571
  • wos:000395001300015
ISSN
1431-2174
DOI
10.1007/s10040-016-1497-5
language
Spanish
LU publication?
yes
id
fdc907a7-ff45-47bd-ac45-2236e75df453
date added to LUP
2016-12-19 07:46:07
date last changed
2018-01-07 11:41:24
@article{fdc907a7-ff45-47bd-ac45-2236e75df453,
  abstract     = {<p>Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.</p>},
  author       = {Doughty, Christine and Tsang, Chin Fu and Rosberg, Jan Erik and Juhlin, Christopher and Dobson, Patrick F. and Birkholzer, Jens T.},
  issn         = {1431-2174},
  keyword      = {Drilling,Fractured rock,Hydraulic head,Hydraulic testing,Well logging},
  language     = {spa},
  number       = {2},
  pages        = {501--517},
  publisher    = {Springer},
  series       = {Hydrogeology Journal},
  title        = {Registro de conductividad eléctrica en el flujo del fluido de un pozo profundo durante y después de la perforación : estimación de trasmisividad, salinidad del agua y carga hidráulica de las zonas conductivas},
  url          = {http://dx.doi.org/10.1007/s10040-016-1497-5},
  volume       = {25},
  year         = {2017},
}