READ ME
This repository includes raw and analyzed data associated with the characterization and measurements of wavespeeds
 in Sample Ceramic #2 as part of the M.Sc. thesis of Helen Yam (Yam, H., CO2 Rock Physics: A Laboratory Study, 
M.Sc. Thesis, University of Alberta, https://doi.org/10.7939/R36704, 2011).  Some of these data are presented 
and analyzed further in Schmitt, DR, G. Davila, H. Yam, G. Njiekak, and R. Kofman, Effects of CO2 Phase State on 
the Seismological Properties of Porous Materials: Implications for Seismic Monitoring of Volcanic Hazards and S
equestered Carbon submitted to the Geological Society of London Special Publication 
Enabling Secure Subsurface Storage in Future Energy Systems, 2022.

Data are contained in Zipped Folders
I. Ceramic Characterization  (See Yam(2011) for more details)
    A. Mercurcy Porosimetry: Contains File CER-08.XLS  - Excel file containing raw Hg injection porosimetry data
    B. SEM Pictures: Contains 9 SEM images of the sample at various magnifications
    C. Air permeability ceramic: Contains measurements of the air permeability 
    D. Tortuosity:  Electrical measurements used to estimate tortuosity

II. Ultrasonic Waveforms
    Note:  Each folder contains the individual raw text files (no file extension) and a corresponding excel file for each measurement made. 
Within a given folder the filenames are have the form of P_## or S_## that respectively refer to P-wave or S-wave measurements. The number ## signifies 
the order of the measurement within the given suite only with the individual pressure conditions indicated in each files header. 
Within each file the columns are arranged as:
X Values = Time in the trace in seconds (10 ns sampling)
Y Values = Trace amplitude (in Volts, obtained from stacking 1000 traces). 
Confining Pressure (MPa) = Pressure in the pressure vessel to which the sample is subject externally. 
Pore Pressure (MPa) = Pore fluid pressure in the sample.  Note that when the sample is under vacuum or at room pressure this value will fluctute and should be ignored. 
Temperature = Temperature in °C as measured by the thermocouple at the time the waveforms were acquired. 
The Files are:
    A. DRY-March 17  :Traces for first suite of 'dry' measurements with pore space at low vacuum. 
    B. march 22 - dry  :Repeat of 'dry' measurements with pore space at low vacuum.
    C. march 19 - N2-temp=42C  :Series of measurements with N2 saturation carried out at constant 42°C including
         1. Nitrogen-heat up  :Wave speeds measured during the initial heating of the sample,  Pc maintained at 30 MPa with Pp at 15 MPa
         2. Pc=40MPa- Pp=varying  :Wave speeds measured while maintining Pc at 40 MPa and Temperature at 42°C, but varying the Pp to determine degree of pressure dependency of dry frame. 
         3. Pc=15MPa  :Waveforms observed under N2 saturation at constant Temperature of 42°C while maintaining constant Terzhagi differential effective stress of Pc-Pp = 15 MPa. 
    D. march 23-CO2 T=23C  :Measurements at room temperature with CO2 saturation
         1. Const Pd=15MPa  :Waveforms observed under CO2 saturation at constant Temperature of 23°C while maintaining constant Terzhagi differential effective stress of Pc-Pp = 15 MPa. 
         2. Const Pd=15MPa#2 :Repeat of above
         3. Pc=40MPa RM Temp   :Measurements with variable Pp at constant Pc = 40 MPa. 
    E. march 24-CO2 Pp=25MPa   :Measurements at Pc = 40 MPa, Pp = 25 MPa with variable temperature
    F. march 24-CO2 T=45C   :Measurements at constant Pe = Pc - Pp with constant Temperature of 45°C
    G. march 25-CO2 Pp=10MPa  :Measurementa at constant Pc = 25 MPa and Pp = 10 MPa with variable temperature
    H. march 25-CO2 T=40C  :Measurements at constant Pe = Pc - Pp with constant Temperature of 40°C
    I. march 26-CO2 T=28C   :Measurements at constant Pe = Pc - Pp with constant Temperature of 28°C
    J. march 27-CO2 Pp=7MPa  :Measurementa at constant Pc = 25 MPa and Pp = 7 MPa with variable temperature
    K. march 27-CO2 T=55C  :Measurements at constant Pe = Pc - Pp = 15 MPa with constant Temperature of 55°C
    L. Nitrogen  :Repeat vacuum and N2 measurements to determine if sample had changed at end of measurmeents 
    M. Sept 19-water :Measurements under water saturation. Note that these files are in original binare from the digital oscillscope.  Use the included Matlab script sigread.m to obtain values. 
    N. Buffer Delay Time Analysis :Calibration of the aluminum buffer rod transit times. 

III. Velocities : This zipped folder contains the analysis leading to the determinations of the wave speeds in excel format as well as a short summary report. 

Contact: Douglas Schmitt.  schmitt@purdue.edu or dschmitt@ualberta.ca
Prepared February 26, 2022.