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Overview
   
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Logging

July 13-17, 1999

The Lamont Doherty Earth Observatory's Borehole Research Group (BRG) logged one hole at the Black Rock Forest in Cornwall, NY. The equipment was brought to the site via West Central Towing. In attendance were Greg Myers, Dave Goldberg, Walt Masterson and Erich Scholz. The tool suite consisted of:

  1. TAP - Temperature acceleration and pressure is designed to measure fluid temperature and pressure and store the data in memory.

  2. Analog Borehole Televiewer (BHTV) – The BHTV captures acoustic images of the borehole wall and “writes’ the images onto Polaroid film. The film is digitized post logging for data analysis.

  • The hole was 140 meters deep with water at 53 m.

  • A trailer mounted logging winch was used to raise and lower the tool. The winch had a functioning analog totalizer for depth.

  • One run was made with the TAP tool in memory mode and one run was made with the BHTV.

  • Following the BHTV run, the TAP tool was reinitialized and lowered to 138 meters to record temperature and pressure over a 3 day period. Logging operations were terminated at 7:30 pm on the 13th.

  • BRG personnel returned to the site on Saturday, July 17 and removed the tool from the hole. The data was downloaded from the tool at 9am .


September 7, 1999
  1. Gamma and Caliper data were acquired to total depth (140m).

  2. The gamma/caliper sonde consists of:

  • A sodium iodide scintillation crystal which measures total gamma ray counts

  • A three-arm caliper which measures average borehole diameter

   
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Data Processing and Quality Control

All data are uncorrected for hole size and environmental factors.Digital depth was not acquired at the time of logging therefore, log depth is derived from pressure data

  • Gamma
    Gamma data are to be used for qualitative analysis only as the measurement has not been calibrated in a certified facility. To ensure the data were reasonable prior to tool deployment, a small calibration source was used to simulate a slightly “active” formation. The data represent the total gamma counts at each depth interval in counts per second (cps). The depth index column was added post logging. No environmental corrections were applied to these data.

  • Caliper
    Caliper data were calibrated with 3-calibration “rings” prior to deployment. The caliper data was recorded in inches and converted to centimeters. No environmental corrections were applied to these data.

  • Temperature and Pressure
    Temperature and pressure data were acquired at 1 sample per second. The units for temperature and pressure is degrees C and PSI respectively. Pressure data is relative, not absolute. No environmental corrections were applied to these data.

   
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Logging Operations
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Borehole Research Group at Lamont-Doherty Earth Observatory of Columbia University, 61 RT 9W, Palisades, NY 10964