This directory contains surface and downhold seismic data obtained near wellbore
4Q66W3 primarily on October 13 and early October 14, 2006. 

This note briefly outlines what is in the files.


XXXX.dat files contain the raw SEG2 format records collected. Note that these are quite variable 
as the number of noise channels consistently changed with different deployments of the 
surface geophones. 

Aside from some of the early shots (e.g. 2001 and 2003 from which data are taken traces in the data files are assigned as:
Channel 9 (trace 1) =  Pilot for vibrator shots or no data for dynamite
Channel 25-48 (trace 2 - 25) = the 24 downhole phones (8 depths X 3 detectors/depth ordered as V,H1,H2). 
Channel 49-240 = (trace 26 to ??) = surface phones. Note that the number of these varied with the last sets only including the first 24.

There were two surface dynamite points called 'near' and 'far'.  These points changed with time 
due to failure and consequent replacement of the shot holes. 
There were two surface vibrator points near the wellbore called P (U of A vibe) and S (GSC vibe)
These positions are coded as 1.X = near shot hole with X signifying the shot hole employed.
2.x = far shot hole.
3 = P vibe 
4.1 = S vibe with .1 signifying that the polarization of the vibe was radial to the borehole at the surface.

4Q66W3.xls = The distilled geometric information is saved in a number of worksheets in the Excel file 4Q66W3

4 organized SEGY Format Files for the downhole responses
There are 192 depth levels at a 5 meter spacing, receiver stations are enumerated beginning with 1001 at the bottom 
of the hole and increasing with each 5 meter level.
Hence each of these contains 3 X 192 (for downhole) + 1 X 192 (for reference) = 768 traces.
Reference was one of the surface channels for the dynamite data.  Note that there was some concern as to absolute timing of the dynamite shots.
However, examination of the reference surface channel indicates that although this delay is unknown the trigger delay is constant.

4Q66FDYN.sgy:  Far Dynamite data. Dynamite data acquired at 250 ms sample period for 12000 samples. SGY files contains only 4000 (1 second) of this data. 
4Q66NDYN.sgy:  Near Dynamite data

4Q66PVIB.sgy:  P wave Vibrator data  Vibrator data acquired a 1 ms sample period for 3000 samples, SGY files contain only first 1000 (1 second) of this data.
4Q66SVib.sgy:  S wave vibrator data

recmake.m = Matlab program to put the geometry files Shots.txt and Receivers.txt
sorter.m = Main matlab program to read and sort the traces, to apply appropriate text, binary, and trace header
information, and to save the final sgy files described in the previous paragraph. 
This program can be rerun if necessary to change the delays or record lengths.  Note that sorter requires
both the programs in this same directory of geode_seg2read.m (specially prepared for this data set), sgywrite_full.m, and
and recmake.m.