Black Rock Forest Overview

Overview

 

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:

 

  • TAP – The temperature acceleration and pressure tool measured fluid temperature and pressure and stored the data in memory.
  • Analog Borehole Televiewer (BHTV) – The BHTV captured acoustic images of the borehole wall and “wrote’ the images onto Polaroid film. The film was 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
Gamma and Caliper data were acquired to total depth (140 m).

 

The gamma/caliper sonde consisted of:

  • A sodium iodide scintillation crystal which measures total gamma ray counts
  • A three-arm caliper which measures average borehole diameter

 

Data Processing & Quality Control

 

All data were uncorrected for hole size and environmental factors. Digital depth was not acquired at the time of logging, therefore log depth was 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.

Logging Operations Image Gallery