Borehole geophysics

BGS staff in the Groundwater Science Programme undertake routine and specialist geophysical logging in both open and cased holes for a wide range of hydrogeological purposes. The facility is based at the BGS Wallingford site but operates throughout the UK and in some cases internationally.

Logging capability

We are able to offer vehicle mounted logging equipment to suit specific requirements. Our main logging system is Land-Rover mounted, has a depth capability of 650 m and provides digital data acquisition at one centimetre resolution using a range of multiparameter slimline tools which include

A lighter weight vehicle mounted system in an Isuzu Rodeo used in collaboration with University College London (UCL) has a depth capability of 150 m. A duplicate set of tools are available. This equipment is being used principally in support of PhD research activities.

Images

Field copies of logs are available from thermal printers in the field or may be processed using either VIEWLOG* or WellCAD** software to provide colour composite plots, including optical or acoustic imagery at any scale required. Interpreted imagery including correlation and statistical outputs can be provided.

*Viewlog Systems Inc, Toronto, Canada

**Registered Trade Mark of ALT

Why log boreholes?

Geophysical borehole logging is a cost effective way of providing vital subsurface information required by geoscientists in groundwater, environmental, mineral and geotechnical investigations.

In newly-drilled boreholes geophysical logging is used

  • to guide the design of the borehole and its completion (construction logging)
  • to identify the lithological sequence and the vertical and lateral variation in rock properties (formation logging)
  • to identify the fluid-bearing potential of the individual layers (fluid logging)

The logging may provide a correlation of the newly drilled section with known geology nearby so that the lateral extent and thickness of aquifers and aquicludes can be determined. Where loose or unconsolidated materials are penetrated logging is essential

  • to guide the design of the well and the selection of well screen and gravel pack and their proper placement (formation, construction, fluid logging)

In existing boreholes geophysical logging is used to

  • provide information on the borehole construction (construction logging)
  • monitor borehole performance, examine reasons for borehole failure, decline in yield, sand pumping or water quality deterioration (various logs)
  • identify the position and relative magnitude of water inflows including pollutants (formation and fluid logging)
  • provide information to correlate similar rock and aquifer horizons from site to site (formation and fluid logging)
  • provide data to examine horizontal-, vertical- and time-varying water quality changes (fluid and geochemical logging)
  • to identify fractures and fissures and distinguish those that are groundwater-active (formation and stress fluid logging)

Used alone or in conjunction with other data e.g. pore fluid geochemistry, hydraulic properties, pump test data, borehole logging provides a powerful tool for investigating hydrogeology and resolving problems in both the saturated and unsaturated zone.

Expertise

We have extensive experience of logging operations in the UK and overseas for a wide range of clients including Government agencies and private sector consultancies.

Our logging service typically ranges from basic log acquisition for a single borehole to comprehensive interpretation of composite logs for a site or region incorporating other hydrogeological data collated specifically or already available. Processing and interpretation of clients' own logs and its integration with other hydrogeological information is also undertaken. Logs run or processed are databased with strict client confidentiality.

BGS holds records and logs from over half-a-million boreholes distributed throughout the UK and this information can be used to geologically classify and make regional interpretation of new logging data.

Recent BGS Internal Activities

  • Science Newcastle Geothermal Research Borehole, Coal Measures
  • London Basin 3D Model of the Chalk
  • Permo-Triassic structures and fracture characterisation, Cumbria
  • Nitrate profiles and Chalk characterisation, Hampshire

Recent Clients

  • URS/Chevron
  • URS/W. Malcolm Ltd
  • Newcastle University
  • CocaCola Beehive/G Saul
  • URS/Pfizer
  • Environment Agency
  • United Utilities

Contact

For further information please contact Andrew Butcher