WORKED EXAMPLE Loading and using Core Analysis Data Core Analysis Data is frequently not available at exact well increments. In order to retain the exact depth at which this data is sampled, it needs to be loaded into the Core Analysis (.COR) file associated with the well. The Core Analysis file has a fixed set of fields in which to store data. These are : Sample ID (text) Recorded Top Depth of sample Recorded Bottom Depth of sample Porosity Horizontal Permeability Vertical Permeability 90 Degree Permeability Klinkenberg Permeability Oil Saturation Water Saturation Bulk Density Bulk Mass Oil Bulk Mass Sand Bulk Mass Water Bulk Volume Oil Bulk Volume Water Grain Density Grain Mass Oil Grain Mass Water Description (text) All fields not marked as text are stored as floating point numbers to at least 3 decimal places. Each entry must have a Recorded Top Depth entry, all other entries are optional. In addition to these fields, TerraStation automatically inserts Top Depth and Bottom Depth fields. Initially these are set to the same values as the Recorded Top Depth and Recorded Bottom Depth fields, but if you shift the core analysis data within TerraStation it is these fields that are altered (and subsequently used when displaying the data). This allows you to shift your core data whilst retaining a record of the original depths that came with it. Page 1
Core Analysis Data is usually read in from ASCII files, often saved in.csv format from a spreadsheet. For example, "SAMPLE","DEPTH","PERMEABILITY","POROSITY","GRAIN DENSITY" "Number","(m)","(mD)","%","(g/cm³)" 1,1426.08,0.13,5.86,2.71 2,1426.9,0.7,9.01,2.7 3,1427.38,0.6,7.66,2.7 etc. etc. In this example there is only one depth associated with each sample, and one permeability (you will need to decide whether to store it as Horizontal, Vertical, 90 degree or Klinkenberg Permeability) 1. Loading the Data Start TerraStation and select the correct project. From the Input/Output menu on the main menu bar, select Well Import then Core Analysis Data. Page 2
Click the Select Input File button and select the text (.csv) file containing the data to load. Set the Incoming File Format toggle to Comma Delimited for a.csv file, or as appropriate for other types of file. Enter the number of header lines 2 in this example. Make sure that the Well(s) to load data into toggle is set to Single Well Mode and then click the Select Well button and select the correct well. Your screen should now look something like this : Click Next. Page 3
The display changes to show your data separated into it's columns, like this : If the display does not look right, you can click Back to return to the previous panel and change the format type. Page 4
Once the columns of data are properly displayed, with the last few lines of the header in the grey band at the top and a gap between that and the first line of data, you need to tell TerraStation which column to load into which field in the Core Analysis file. You do this by moving the mouse pointer into each column in turn, clicking the right mouse button and selecting the appropriate field from the menu that appears. For example : As you do this for each column, the field that you have selected for that column will appear in the blank line between the header and the first line of data, like this : Page 5
Once you have identified all of the columns of data you wish to load, make sure that the Incoming Depth Units toggle is set correctly. Also, if you have values in your file that represent missing data (-999.0 or -999.25 are commonly used for this purpose), enter that value into the Incoming NULL value dialog box. When you have done all of this, click Next to load the data. Page 6
A report window will appear (sometimes behind the main loading window) giving a summary of what has been done. Close this window when you have read the report, then click Done to close the main loading window. Page 7
2. Verifying that the data has loaded correctly. You can check that the data has loaded correctly by starting the Petrophysics module, clicking the Well Properties button on the Powerbar, selecting the Scout Ticket tab and highlighting Core Data File in the Scout Ticket Data list. Then click Edit to bring the file up in the ASCII Editor. Note that -999.000 is used as the NULL value in the Core Analysis Data file. Close the Editor window when you are finished, then close the Well Properties window. Page 8
3. Using Core Analysis data in Crossplot. To plot the Porosity vs the Permeability from the Core Analysis Data file in Crossplot, first start the Crossplot module (from Petrophysics). In the Crossplot Display Preferences, General tab, first set the second toggle under Curve Control (circled on the right) to Core Data (be careful not to select Core Image Data which is also available from this toggle!). Now click on the X Curve button. Instead of getting the list of curves in your well file, you will be presented with the list of fields in the Core Analysis Data file. Select the one you wish to use (e.g. POROSITY). Page 9
Repeat for the Y Curve and then click Apply to view your crossplot. All of the normal crossplot functionality is available to you. Page 10
To crossplot data from the Core Analysis Data file against standard log data from the well file, you proceed in exactly the same way except that you change the Curve Control toggle before selecting the curve for each axis. For example, to plot Porosity from the Core Analysis Data file against a deep resistivity curve, you would set the toggle to Core Data, click the X Curve button and select POROSITY, change the toggle back to Well Curve Data, click the Y Curve button and select LLD, then click Apply to get a crossplot something like this: The Deep Resistivity values are interpolated to the exact depths of the points in the Core Analysis Data file. Page 11
4. Using the Core Analysis Data in IMAGELog You can display Core Analysis Data in an IMAGELog curve track. In the Track Configuration for the Curve track, set the Curve Source toggle to Core Data then click Select Curves and select the field(s) you wish to display in this track. Page 12
It is recommended that you use one of the symbol line styles to display data from the Core Analysis Data file. Page 13
It is possible to mix data from the Core Analysis Data file with curves from the well file in the same curve track. To do this, first make sure that the Curve Source toggle is set to Well Curve Data. Click Select Curves and select the curves you want to display. Then change the Curve Source toggle to Core Data, click Add Curves (NOT Select Curves, otherwise you will replace the curves you already selected) and select the Core Analysis Data fields you want to display. Remember that the grid type (linear or logarithmic) is determined by the first curve you select. Page 14