Petrophysics
Petrophysics
Introduction
Creating Petrophysics summary tables is usually a very tedious chore that is often done under stressful conditions. Henderson Petrophysics has developed an EXCEL spreadsheet program that uses Visual Basic for Applications (VBA) macros to very quickly create zoned Petrophysics summary tables from CPI (Computer Processed Interpretation) data listings.
Figure 1 shows an example Petrophysics Summary table created with the application. The Worksheet is automatically date and time-stamped so that multiple interpretation tables can be compiled. This is very useful when your project Geologist changes reservoir tops and asks for an updated Summary table
Figure 1: Example Petrophysics Summary Table Software for Creating Zoned Petrophysical Summary Tables
The Henderson Petrophysics Free Downloads section contains an example EXCEL Spreadsheet, a Visual Basic Macro file and associated documentation for processing Petrophysics data to create zoned summary tables.
The EXCEL Spreadsheet contains Visual Basic for Applications Macros that process data. This Spreadsheet is intented only for advanced EXCEL users who are familiar with using Visual Basic macros. Please look at the ReadMeFirst text file before attempting to open the Spreadsheet. This file discusses issues arising from the use of Spreadsheets with embedded Macros.
The Zoned Petrophysics Summary User Interface
Figure 2 shows the User Interface used to input parameters required to create the Petrophysics Summary Table. Data is entered in the light blue coloured cells.
Figure 2: User Interface for Zoned Petrophysics Summary The CPI Data Worksheet
Figure 3 shows part of the data set used in the example Spreadsheet. The log data is in columns with the first row containing the curve name. The data must start in row 2 and there cannot be any blank rows in the data set.
The VBA macros look for a depth reference column that must contain the letters "DE" (for example DEPTH, DEPT, DEPTH_TVD, DEP_SS, etc). If necessary, rename your reference column or create a copy and call it "DEPTH".
The CPI data set must contain columns with porosity, water saturation and shale fraction data. Permeability data will be processed if it exists in the data set. Names containing either "POR" or "PHI" will be interpreted as porosity data. Names containing "VCL" or "VSH" will be interpreted as shale fraction data. Headers with "SW" and "PER" will be interpreted as water saturation and permeability respectively.
If your data set contains more than one porosity and/or water saturation column, move the unwanted columns away from the analysis area (separated by at least one column) as shown by example in figure 4. Alternatively, since the top row of the CPI data sheet is scanned from left to right, it is possible to organise the data so that the required data is the last scanned.
You can organise your CPI data set to create multiple interpretations. For example, use PHIE and SWE in one table and PHIT and SWT in another. Another possiblility is to investigate the effect of using either VShale or VClay as a Net reservoir cutoff indicator.
Figure 3: Example Petrophysics data sheet
Figure 4: Example Petrophysics data sheet with data segregation Working With Macros in EXCEL
The example EXCEL Spreadsheet available from our Download section contains Visual Basic for Applications Macros that process Petrophysics data. This Spreadsheet is intented only for advanced EXCEL users who are very familiar with Petrophysics data analysis and the use of Visual Basic macros. Please look at the ReadMeFirst text file before attempting to open the Spreadsheet. This file discusses issues arising from the use of Spreadsheets with embedded macros.
Figure 6 shows the warning window displayed by EXCEL when you open a Spreadsheet containing macros. We suggest that you open the Spreadsheet "Petrophysics_Summary_Tables.xls" with the macros disabled. To do this, choose the EXCEL option Tools/Macros/Security and select the High secrutity settingTo examine the macros, type Alt+F11 to open the Visual Basic Project Manager. After convincing yourself that the macros are not harmful to your computer system you can re-open the Spreadsheet with the macros enabled. Alternatively, you can use our macros as a learning resource for developing your own Petrophysics macros.
If you are interested in discovering how the VBA macros work, open the VBA project manager from EXCEL by typing Alt+F11. You can then step through the macros by typing F8 continuaously.
Figure 6: EXCEL Warning window when opening a Spreasheet containing macros
How to Contact Us
In additional to informative articles and useful downloads, our Website contains a lot of information on the services and expertise offered by Henderson Petrophysics.
Henderson Petrophysics Home Page Henderson Petrophysics offers specialised formation evaluation services to the upstream oil and gas business.
For more information on our services or our fee schedule you can send an e-mail (click on the icon below) or contact us using the following information;
Phone: +61 7 3300 3980 (61 is the country code for Australia and 7 is the area code for Brisbane)
Fax: +61 7 3300 9342
Skype: User ID is DonHenderson4061, or search using my e-mail address don@hendersonpetrophysics.com
E-mail: don@hendersonpetrophysics.com
