Databank

Workreport 1997-43

Back

Name:

Romuvaaran syväkallion yksityiskohtainen rakotietokanta

Writer:

Pirjo Hellä; Sonja Voipio; Tuija Hänninen; Henry Ahokas; Eero Heikkinen

Language:

Finnish

Page count:

253

Summary:

Working report: Hellä, P., Voipio, S., Hänninen, T., Ahokas, H. and Heikkinen, E. 1997. Detailed fracture
database from deep boreholes at Romuvaara site. Work report 97-43. Posiva Oy, Helsinki. 251 p .
(in Finnish).


ABSTRACT

Posiva Oy studies the Finnish bedrock for the final disposal of the spent nuclear fuel. Preliminary site
investigations were carried out at five sites, Kuhmo, Hyrynsalmi, Konginkangas, Sievi and Eurajoki
during 1987-1992. Detailed site investigations have continued at Romuvaara in Kuhmo, at Kivetty in
Äänekoski and at Olkiluoto in Eurajoki since 1993. In the beginning of 1997 the investigations started
also at Loviisa Hästholmen. The investigations at these four sites will continue until 2000 when the site
for final disposal of the spent nuclear fuel will be selected.

The fracture database is integrated and collected from several geological studies and geophysical
measurements. The data sources are core mapping, mineralogical fracture study, electrical dipmeter,
acoustic televiewer and borehole TV. At Romuvaara the work covered the boreholes KR1, KR2, KR3,
KR4 and KR10 within vertical depth range 300 - 800 m. The extended part of borehole KR2 drilled in
1994 is not included in the database. Other data utilised has been hydraulic conductivity values and
directional borehole radar reflections. Data was error checked first method by method and converted to
uniform format. Depth calibrations were carried out for each method separately.

The automatic fracture integration process was realised with computerised Fracture Data Composition
(FDC) program. The integration is based on multiparameter optimisation which handles both geometric
and parametric values. The process is a two phase one: first between core data and each logging method
data subsequently followed by multimethod data combination. In the automatic process 87 % of
fractures were joined. The portion left was joined with the help of expert judgement.

The fracture database was coded into a MS Excel format table and into WellCAD database for graphics
presentation. The database contains information from 1951, 557, 636, 507 and 1106 fractures from
boreholes KR1, KR2, KR3, KR4 and KR10, respectively. Two combined logs from each borehole
contain all data plus hydraulic conductivity values and borehole radar reflections. The most important
result is the increase of the number of oriented fractures previously between 0 - 28 % and now up to 41
- 76 % level. Similar results are also valid in identified structural units. Previously the portion of
oriented fractures was low 0 - 30 %, but could now be raised up to range between 39 - 91 %. The total
number of identified fractures has been increased by 9 - 36 %. Most frequently hydraulically
conductive sections show occurrence of open fracture(s). The fracture database makes it also possible
to compare the correspondence of oriented borehole radar reflections to oriented borehole fractures in
the future.

Keywords: Fracture database
Hellä, P., Voipio, S., Hänninen, T., Ahokas, H. and Heikkinen, E. 1997. Detailed fracture
database from deep boreholes at Romuvaara site. Work report 97-43. Posiva Oy, Helsinki. 251 p .
(in Finnish).


ABSTRACT

Posiva Oy studies the Finnish bedrock for the final disposal of the spent nuclear fuel. Preliminary site
investigations were carried out at five sites, Kuhmo, Hyrynsalmi, Konginkangas, Sievi and Eurajoki
during 1987-1992. Detailed site investigations have continued at Romuvaara in Kuhmo, at Kivetty in
Äänekoski and at Olkiluoto in Eurajoki since 1993. In the beginning of 1997 the investigations started
also at Loviisa Hästholmen. The investigations at these four sites will continue until 2000 when the site
for final disposal of the spent nuclear fuel will be selected.

The fracture database is integrated and collected from several geological studies and geophysical
measurements. The data sources are core mapping, mineralogical fracture study, electrical dipmeter,
acoustic televiewer and borehole TV. At Romuvaara the work covered the boreholes KR1, KR2, KR3,
KR4 and KR10 within vertical depth range 300 - 800 m. The extended part of borehole KR2 drilled in
1994 is not included in the database. Other data utilised has been hydraulic conductivity values and
directional borehole radar reflections. Data was error checked first method by method and converted to
uniform format. Depth calibrations were carried out for each method separately.

The automatic fracture integration process was realised with computerised Fracture Data Composition
(FDC) program. The integration is based on multiparameter optimisation which handles both geometric
and parametric values. The process is a two phase one: first between core data and each logging method
data subsequently followed by multimethod data combination. In the automatic process 87 % of
fractures were joined. The portion left was joined with the help of expert judgement.

The fracture database was coded into a MS Excel format table and into WellCAD database for graphics
presentation. The database contains information from 1951, 557, 636, 507 and 1106 fractures from
boreholes KR1, KR2, KR3, KR4 and KR10, respectively. Two combined logs from each borehole
contain all data plus hydraulic conductivity values and borehole radar reflections. The most important
result is the increase of the number of oriented fractures previously between 0 - 28 % and now up to 41
- 76 % level. Similar results are also valid in identified structural units. Previously the portion of
oriented fractures was low 0 - 30 %, but could now be raised up to range between 39 - 91 %. The total
number of identified fractures has been increased by 9 - 36 %. Most frequently hydraulically
conductive sections show occurrence of open fracture(s). The fracture database makes it also possible
to compare the correspondence of oriented borehole radar reflections to oriented borehole fractures in
the future.

Keywords: Fracture database

Keywords:

rakotietokanta

File(s):

Romuvaaran syväkallion yksityiskohtainen rakotietokanta (pdf) (10.8 MB)


Back


Share article:
This website stores cookies on your computer. These cookies are used to improve our website and provide more personalised services to you.
Close

Cookies

To make this site work properly, we sometimes place small data files called cookies on your device. Most big websites do this too.

1. What are cookies?

A cookie is a small text file that a website saves on your computer or mobile device when you visit the site. It enables the website to remember your actions and preferences (such as login, language, font size and other display preferences) over a period of time, so you don’t have to keep re-entering them whenever you come back to the site or browse from one page to another.

2. How do we use cookies?

A number of our pages use cookies to remember your actions and preferences (such as login, language, font size and other display preferences.)

Also, some videos embedded in our pages use a cookie to anonymously gather statistics on how you got there and what videos you visited.

Enabling these cookies is not strictly necessary for the website to work but it will provide you with a better browsing experience. You can delete or block these cookies, but if you do that some features of this site may not work as intended.

The cookie-related information is not used to identify you personally and the pattern data is fully under our control. These cookies are not used for any purpose other than those described here.

3. How to control cookies

You can control and/or delete cookies as you wish – for details, see aboutcookies.org. You can delete all cookies that are already on your computer and you can set most browsers to prevent them from being placed. If you do this, however, you may have to manually adjust some preferences every time you visit a site and some services and functionalities may not work.

Close