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icdp Downhole Logging

...keep calm and carry on logging

The support offered by OSG ranges from the evaluation of logging provider quotations, support in the planning and management of well logging programs of ICDP proposals, to the actual performance of downhole logging. Our support in the preparation of well logging programs includes checking the availability of equipment and necessary expertise, and an assessment of quoted costs.

On request, the OSG can carry out borehole measurements (service) with special logging equipment that is suitable for most ICDP drilling conditions. The OSG also supports the evaluation of downhole logging data.

OSG logging services must be performed in accordance with the icdp-OSG Health & Safety regulations


OSG offers logging service for ICDP projects. OSG logging can complement any other logging program or form the entire downhole logging of a project. Costs are minimal and comprise only very low tool utilization costs and travel/transport costs of personnel and equipment. No depth or measurement charges and no personnel costs are imposed but these are borne by overall ICDP funds. The low costs enable downhole logging even for ICDP projects with a low budget.

OSG logging services must be performed in accordance with icdp-OSG Health & Safety regulations


Our equipment

Based on the most frequent requirements of ICDP projects we established ICDP downhole logging equipment with slimhole sondes and suitable logging winches. The tool specifications allow utilization in various hole conditions. ICDP also operates logging tools and winch systems owned by GFZ Potsdam. 

OSG cannot and will not compete with commercial logging service providers. OSG recommends the use of commercial services if these provide higher resolution and/or quality and if the project budget allows.

Logging contract

A logging contract addresses the duties, rights and non-liabilities of OSG and the PIs. A pre-operation checklist identifies the conditions for downhole logging in the planned new project and is filled out by the PI(s). Availability of OSG services is handled on a first-come-first-serve basis. As there is only one OSG logging team a delay in a preceding project potentially may cause schedule conflicts with the following project. ICDP tries to avoid conflicts by scheduling only two or three projects per year, several months apart.  

The borehole data measured by the OSG/GFZ is made available only to the members of the science team via the GFZ data server shortly after drilling only to the members of the science team and then to the public after the moratorium has expired, also to the public.

Planning, Design & Management

We help PI's of ICDP projects to develop and optimize a downhole logging plan for the individual scientific targets and conditions of their project. Our extent of help depends on the requests of the PI's. It can range from just providing information on time and availability for logging methods to the creation of an entire logging plan. The close in-house cooperation with our other OSG experts (drilling, core handling and data management) assures smooth and optimized operations. If desired, we can also assist in the management of logging activities. 

Our participation in downhole logging operations is not mandatory. OSG consulting is free of charge for ICDP projects but any travel costs incurred will be charged to the project.

As a first overview, the diagram can help you to decide which log types are suitable for your specific project goals. We are happy to help you develop a customized logging plan. 

Logging Time / Cost Calculator
The OSG logging time and costs scheduler can be used to get a very first overview of the required logging time and costs. It is an MS Excel sheet that easily allows to assess the time frame necessary to carry out the desired logs by OSG.
Further it gives a first rough number on the expected costs for the complete OSG logging operations, including transport, travel and personnel costs. It excludes rig time costs, i.e. costs that arise during stand-by of the drilling rig, the drilling crew and associated companies as these items strongly vary in different projects.

OSG Logging Time & Cost Calculator

Logging check list
For a reliable and more precise estimation of logging time and costs please contact us. It is helpful to send the filled out MS Excel sheet. At this later stage, more detailed information about the desired logging parameters are required. In case the project is already in an advanced state it is very helpful to fill out our check list as best as possible.

OSG Logging Checklist

The currently four-member OSG downhole logging team are (from left to right):

Jochem Kück (head of the logging team) 

Martin Töpfer (logging technician)

Marco Groh (logging engineer)

Simona Pierdominici (logging data evaluation) 


Former members were:

Karl Bohn, Christian Carnein, Miel Kühr, Matxalen Rey

Logging Infrastructure

Our downhole instruments infrastructure is optimized for slimhole conditions but can be used in wider boreholes with some limitations. 

We utilize slimhole logging sondes (mostly < 52 mm, one tool with 61 mm) that cover the basic geophysical logging parameters, see photos below. The majority are wireline sondes, with online data transmission operated on a special logging cable. A smaller set of four sondes can be used in an autonomous memory mode, typically together with a drill string in what is called logging while tripping out the drill string. This operation mode is recommendable in very unstable formations, which frequently occur in lake drillings, or in highly deviated boreholes (> 45°).  

The wireline sondes are rated 150 °C/50 MPa, except for the acoustic imager (125 °C), the borehole geophone chain (135 °C), and the fluid sampler (180 °C).

The memory tools are rated 70 °C/50 MPa. No special logging cable and winch is required. Alternatively, however, these sondes can be run online in wireline mode, like a regular wireline logging sonde. 

For borehole seismics we also provide service with the SlimWave Geophone Chain, see photos below. It has a maximum number of 17 levels with 3-component 15 Hz geophones each (not oriented). The spacing length between levels is 10 m. The chain can be run with a total natural GR and a CCL (casing collar locator). The temperature/pressure rating is 135 °C/100 MPa (short-time 150 °C). Connection via GO7 cable head.

The OSG downhole fluid sampler sonde (see photos below) is a positive displacement type (PDS) that provides a very controlled, slow sampling procedure without sudden decompression and thus without degassing, even at very high borehole fluid pressure. Thus, it also prevents decomposition of microbial DNA. It takes one sample (0.6 liter) at a time. It can be combined with the OSG slimhole fluid  parameter sonde to allow accurate positioning in the flow zone.

All sondes can be used in holes down to 96 mm (typical HQ) and even in 76 mm holes (NQ) if wellbore stability permits. The maximum borehole size differs for each tool. These tools are best run on one of our special slimhole logging winches but can also be run on any logging winch system with at least a 4-conductor cable.

Please note: OSG does not operate tools with nuclear sources!  


Wireline sondes:

  • electrical resistivity (conductive, DLL)
  • sonic velocity (T-R1-R2)
  • natural gamma spectrum (full spectrum)
  • total natural gamma
  • borehole orientation, oriented caliper (4-arm dipmeter)
  • borehole images (acoustic)
  • magnetic field (triaxial magnetometers inside dipmeter)
  • magnetic susceptibility
  • fluid parameters (temperature, pressure, resistivity)
  • spontaneous potential (analog)
  • fluid samples (PDS type sampler)
  • seismic (borehole geophone chain, triaxial, up to 17 levels) 

Memory sondes:

  • electrical resistivity (inductive, DIL)
  • sonic velocity (T1-R1-R2-T2)
  • natural gamma spectrum (full spectrum)
  • total natural gamma
  • magnetic susceptibility

Sonde Specifications (PDF)

Find more details about the memory logging system here.

In 2023/24 OSG is acquiring a new slim micro resistivity imager (sMRI) with 64/176 electrode buttons that will also be rated 125 °C/50 MPa and with a tool diameter of 61 mm.

All sondes are available as logging service only, i.e. operated by experienced GFZ personnel, under the terms of the OSG downhole logging service conditions.


  • MW2000           2200 m, 4-conductor cable, for lightweight slimhole sondes only
  • MW600               600 m, 4-conductor cable, for lightweight slimhole sondes only
  • MW250               250 m, 4-conductor cable, for lightweight slimhole sondes only
  • CW6000           4500 m, 7-conductor cable, heavy duty winch
  • CW7000           7300 m, 7-conductor cable, heavy duty winch

The small MW logging winches are best for shallow to moderate depths. Depths larger than approximately 2000 m and/or heavy sondes can be handled using one of the two heavy duty, containerized CW logging winch units. 

Please find details in the Winch Specifications (PDF)

    All winches are available as logging service only, i.e. operated by experienced GFZ personnel, under the terms of the OSG downhole logging service conditions.


    Most of our logging sondes are operated with the data acquisition software Geobase of the sonde manufacturer Antares. The acoustic imager ABI43 is run with the SCOUT system of the imager manufacturer ALT. These very small and lightweight data acquisition systems GEOBASE and SCOUT both consist just of a laptop and a hand portable tool interface panel. 

    The Antares sondes deliver original raw logging data in the RLF-format that can be read with the Geobase software only. Output is possible in ASCII and DLIS. The SCOUT system delivers data in the TFD format and via the ALT-made WellCAD software an output in DLIS is possible.

    The SlimWave geophone chain is operated with WaveControl/ToolsPilot (Sercel).

    We mainly utilize the WellCAD (ALT) software for data processing and some special modules of Geobase. WellCAD generates its own plot file formats. These can be viewed with WellCAD Data Viewer, which can be downloaded free of charge. Data output file formats are ASCII, LAS and DLIS.


    We manage and operate the KTB Deep Lab of the GFZ (KTB-TL) in Bavaria, southern Germany. KTB was the German Continental Deep Drilling Program, actively drilling between 1987 and 1994. Today, the KTB site with its two closely spaced boreholes (4000 m & 9100 m) is used as a deep laboratory with a complete borehole logging infrastructure, including a workshop for wireline borehole logging. The KTB site allows in-situ high-temperature/pressure testing of logging and downhole monitoring equipment and even long-term testing at low cost. Please click here for more information.

    Data measured during the active KTB drilling phase 1987-1994 can be obtained here

    For data measured in the two KTB boreholes since 1996 please contact us here.

    Find the KTB-Deep Lab on Google Maps.

    For other ICDP equipment please see SUPPORT -> OTHER ICDP EQUIPMENT  

    For external logging equipment from partners please see SUPPORT -> PARTNER EQUIPMENT  


    Logging Data Evaluation

    OSG offers downhole logging data evaluation for ICDP projects. This includes data processing, analysis and interpretation of the entire suite of downhole logging parameters acquired or on only selected data sets. The evaluation will always happen in coordination with the project PIs and the project science team. ICDP's participation in downhole logging data evaluation is free of charge for ICDP projects but is not mandatory. Scientific collaboration in publications is desirable.

    OSG/GFZ measured downhole logging data will be made available to science team members through the GFZ data server soon after the logging operations and to the public at the end of the moratorium period.

      • Sonic p- and s-wave velocity (figure A)
      • Elastic moduli
      • Anisotropy (figure B)
      • Porosity
      • Permeability
      • Fluid content
      • Mineralization, alteration
      • Compaction
      • Identification of e.g. clay intervals, igneous layers and organic matter
      • Lithological classification, interpretation and stratigraphic correlation
      • Electrofacies (figure A)
      • Identification of stratigraphic elements like conglomerates, boundaries and internal structuring of lava flows using acoustic image log
      • Identification of compaction zones
      • Lake cyclo-stratigraphic analysis
      • Lake deposition environments
      • Lake age-depth model from downhole logging data
      • Present-day stress field analysis from borehole breakouts and drilling induced tensile fractures (figure A)
      • Spatial orientation (dip and dip azimuth), distribution and frequency of planar structures intersecting the borehole wall like bedding planes, foliation, folding, faults, and fractures (figure B)
      • Differentiation between closed and open faults/fractures and determination of their opening width
      • Depth matching core to downhole log (figure A)
      • Spatial orientation of cores by comparison of image logs with cores or core scans (figure B)
      • Integration of downhole logging data, core data, and seismic data (core-log integration and core-log-seismic integration) (figure C)
      • The GFZ/KTB developed software CREOS is used for a semi-automatic matching of sine structures viewed both on cores and in image logs for spatial core orientation purpose. Ask us for more information about CREOS.  
      • Borehole geometry: size, orientation and trajectory
      • Temperature profile analysis (figure A) 
      • Recognition of artifacts on borehole images (figure B)
      • Casing inspection (figure C)
      • Overburden stress

      Core-log-seismic integration in metamorphic rocks and its implication for the regional geology: A case study for the ICDP drilling project COSC-1, Sweden. Elger, J., Berndt, C., Kästner, F., Pierdominici, S., Kück, J., Almqvist, B.S.G., Juhlin, C., Lorenz, H (2021). Geochemistry, Geophysics, Geosystems, 22, e2020GC009376,

      Stratigraphic correlation and splice generation for sediments recovered from a large-lake drilling project: an example from Lake Junín, Peru, Hatfield, R.G., Woods, A., Lehmann, S.B., Weidhaas, N., Chen, C.Y., Kück, J., Pierdominici, S., Stoner, J.S., Abbott, M.B., Rodbell, D.T. (2020). J. of Paleolimnology, 63(1), 83-100,

      Understanding volcanic facies in the subsurface: A combined core, wireline logging and image log data-set from the PTA2 and KMA1 boreholes, Big Island, Hawai'i. Jerram, D.A., Millett, J.M., Kück, J., Thomas, D., Planke S., Haskins E., Lautze N., Pierdominici S. (2019). Scientific Drilling, 25, 15–33,

      Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden. Kästner, F., Pierdominici, S., Elger, J., Zappone, A., Kück, J., Berndt C. (2020). Solid Earth, 11(2), 607-626.

      Downhole Logging, in: ICDP Primer - Planning, Managing, and Executing Continental Scientific Drilling Projects, Fifth Edition October 2021, Harms, U. (ed. 2021), Kück, J. Pierdominici, S. (2021), Chapter 4.6, pp 127-151, GFZ German Research Centre for Geosciences,

      Borehole Geophysics. Book chapter in Encyclopedia of Geology, 2nd edition, Pierdominici, S., Kück J. (2021). editors in chief: Scott Elias David Alderton, Elsevier,

      Stress field interactions between overlapping shield volcanoes: borehole breakout evidence from the Island of Hawai´i, USA. Pierdominici, S., Millett, J.M., Kück, J.K.M., Thomas, D., Jerram, D.A., Planke, S., Haskins, E., Lautze, N., Galland, O. (2020). JGR,125, e2020JB019768,

      Past Campaigns

      Past Campaigns Timeline

      SUSTAIN, Surtsey, Iceland

      DeepChalla, Lake Challa, Kenya

      Lake Junín DP, Lake Junín, Perú

      COSC-1 Logging & Seismics, Åre, Sweden

      HSPDP, Baringo, Kenya

      GONAF, Tuzla, Turkey

      HOTSPOT, Mountain Home, Idaho, USA

      Lake Elgygytgyn, Russia

      DAFSAM, Tau Tona Mine, South Africa

      LMDP, Lake Malawi, Malawi

      TCDP, Taichung, Taiwan

      SAFOD, Parkfield, USA

      CSDP, Yaxcopoil, Mexico

      USDP, Shimabara, Japan

      Past Campaigns List

      in chronological order



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