Sonic Waveform Data

 

Site: Lamont-Doherty Earth Observatory, Palisades, NY

Well: Lamont Test Well 3 (TW-3)

Date: 10/4/2013

Logging Company: Schlumberger

Nominal well diameter (bit size): 6.25 in.

Depth range: 0 -1512 ft

Log Sampling interval: 0.5 ft (6 in)

TOOL USED: Sonic Scanner

Recording modes: Monopole P&S Far (low and medium frequency), Lower and Upper transmitter (medium frequency), Cross Dipole.

Remarks about the recording: none.

Number or rows: 2985 (main)

Number or rows: 1876 (repeat)

Number of columns:

lower/upper monopole: 3329

far monopole: 6657

lower monopole/azimuth: 13313

far monopole/azimuth: 26625

cross dipole: 9920

The following files have been loaded:

Main Pass from Sonic Scanner/PPC-B/GPIT/EDTC-B

TW3_far_mono_lf_main.bin: 360-1512 ft

TW3_far_mono_mf_azi_main.bin: 360-1512 ft

TW3_far_mono_mf_main.bin: 360-1512 ft

TW3_lower_mono_mf_azi_main.bin: 360-1512 ft

TW3_lower_mono_mf_main.bin: 360-1512 ft

TW3_upper_mono_mf_main.bin: 360-1512 ft

TW3_X_cdip_cl_main.bin: 360-1512 ft

TW3_X_cdip_il_main.bin: 360-1512 ft

TW3_Y_cdip_cl_main.bin: 360-1512 ft

TW3_Y_cdip_il_main.bin: 360-1512 ft

Repeat pass from Sonic Scanner/PPC-B/GPIT/EDTC-B

TW3_far_mono_lf_rep.bin: 574.5-1512 ft

TW3_far_mono_mf_azi_rep.bin:  574.5-1512 ft

TW3_far_mono_mf_rep.bin: 574.5-1512 ft

TW3_lower_mono_mf_azi_rep.bin: 574.5-1512 ft

TW3_lower_mono_mf_rep.bin: 574.5-1512 ft

TW3_upper_mono_mf_rep.bin: 574.5-1512 ft

TW3_X_cdip_cl_rep.bin: 574.5-1512 ft

TW3_X_cdip_il_rep.bin: 574.5-1512 ft

TW3_Y_cdip_cl_rep.bin: 574.5-1512 ft

TW3_Y_cdip_il_rep.bin: 574.5-1512 ft

All values are stored as '32 bits IEEE float'.

Any image or signal-processing program should allow to import the files and display the data.

For users interested in reading and converting the data to a format more suitable for their own purpose, the fortran declaration used to open the file *.bin would be:

open (1, file = *.bin,access = 'direct', recl = 4*(1+nrec*nsamples))

where nrec is the number of receivers and nsamples the number of samples per waveforms.
If the total number of depths where waveforms were recorded is ndepth (for a 50 ft interval with data every 0.5 ft, ndepth would be 101), a generic loop to read the data would be

do k = 1, ndepth
...
read(1, rec=1+k) depth(k), ((data(i,j,k), j=1,nsamples),i = 1,nrec))
...
enddo

the first record in each file is a header with some of the file specifications storted as integers, unless otherwise specified:
- number of depths
- number of samples /trace
- number of receivers
- tool number = 3 (Sonic Scanner)
- mode (1 = Lower Dipole, 2 = Upper Dipole, 3 = Stoneley, 4 = Monopole)
- vertical sampling interval (IEEE float)
- scaling factor for depth (IEEE float)
- waveform sampling rate in microseconds

Additional information about the drilling and logging operations can be found in the Operations and Downhole Measurements sections of the expedition report, Proceedings of the Integrated Drilling Program, Expedition 3.

For any question about the data or about the LogDB database, please contact LogDB support: logdb@ldeo.columbia.edu.