WellCAD Basics - Advanced Logic Technology

BOOK 1 - WELLCAD BASICS - 125
Constants
A constant is any fixed number, e.g. 1, 3.1415 or –18.5238.
Operators
Legal operators, in the order of precedence, are:
^ exponent e.g. 2 ^ 3 = 8
/ divide e.g. 2 / 3 = 0.666667
* times e.g. 2 * 3 = 6
- minus e.g. 2 – 3 = -1
+ plus e.g. 2 + 3 = 5
The operator precedence order may be modified using parenthesis.
Logs
Well Log or Formula Log data can be referred to into a formula by enclosing their
log title exactly as it appears in the log handle in brackets. E.g. {GR} – {Grmin}
subtracts data from the log Grmin from the log GR.
The Formula Parser provides a special built-in data column referred to by
{DEPTH}, which returns the current depth.
When a formula is applied to a log the log’s depth sampling rate is used to retrieve
the data values and output the result in a Formula Log. If more than one log with
different sampling rates are involved, the minimum sample interval will be taken.
Functions
A list of all functions available is given in Appendix D.
While composing a formula a short explanation about syntax and use of the formula
is given in the Formula Parser dialog box.
The use of the Formula Parser is best explained looking at the simplified example of
computing the density-based porosity in a shaly limestone context given by
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