Single-Value, Array and Table Variables

Variables in PetroVR can be classified in three according to their dimension: Single-value variable single-value variables consist of a unique value, Array variable arrays consist of a series of values spanning over the simulation periods, and Table variable tables present values arranged in rows and columns, typically used to relate series of parameters defined in different unit types.

Most PetroVR system variables are of the single-value type. All examples used in this section of the Help are based on this type. The use of table variables, on the other hand, is covered by the Tables section.

Array variables are relatively few among system variables: only facility Deliverability and CapEx Escalation (see the Depreciation General Tab (Depreciation)). On the other hand, it is common to use User-Defined Variables defined as arrays when available input data (such as e.g. operational costs or available rigs) are broken down into periods.

Apart from commands already described in Commands available (variables) such as CopyCopy, and other more complex options, the following special commands also appear in the right-click menu when editing array variables:

  • Cell: Use Fill left and Fill right to fill in all cells to the left/right of the selected cell with the value of the selected cell.
  • Copy cells: copy the selected range of cells (only numeric values, without units).
  • Copy arrayCopy array: Copy the whole array (only numeric values, without units).

Array variables have exactly as many cells as there are periods in the simulation, according to the periodicity defined in the General Tab. Therefore, modifying the periodicity or the simulation span will affect all existing array variables:

  • If you change the frequency, PetroVR will re-escalate the values adapting them to the new time lapse covered by the period - splitting or combining them depending on whether the new periods are shorter or longer. The logic also takes into account the nature of the value (rate or cumulative):
    • If you change a cumulative array from shorter to longer periods, the last value from the group of periods being combined is used. (PetroVR assumes an array is cumulative if its values are always increasing.)
    • If you change a cumulative array from longer to shorter periods, a constant increase between the resulting periods is used.
    • If you change a rate array from shorter to longer periods, an average value is used.
    • If you change a rate array from longer to shorter periods, the same value is used.
    • Changing the simulation span also affects array variable values:
    • If you add periods, the new ones are filled with the value of the last cell.
    • If you reduce the number of periods, the values of the last cells are lost.