Decline worksheet

Decline worksheets display the production data of a well using the selected plot options (such as, time or cumulative production for the x-axis). These worksheets can be used to add, display, and modify decline forecasts based on your production data. For more information, see the analysis manager and plot selection pane.

Note:    This worksheet works with your Harmony Forecast™ license.

In the decline category, you can select these plot types for gas, oil, water, and barrel of oil equivalent (BOE):

  • Rate Time — production rates are plotted against time on a semi-log plot
  • Rate Cum — production rates are plotted against cumulative production on a coordinate plot
  • Cum Time — cumulative production is plotted against time on a coordinate plot. Note that this is a read-only display and the decline cannot be modified on this plot.

Default decline worksheets can be modified in the Plot Selection pane.

In the Analysis Manager, you can add hybrid forecasts for gas, oil, or water.

You can also add condensate decline analyses (that is, Arps, multi-segment, stretched exponential, and Duong) to your decline worksheet, but the procedure is different. For more information, see analyzing a condensate decline analysis.

BOE

The BOE applies to wells and groups, and it is of interest because oil and gas are often produced together. The BOE is calculated as oil volume + gas volume / factor. This factor can be changed from the default value of 6.00 Mcf/bbl in the Production Calculations section of the Options dialog box (Tools menu, Options).

Important:    This value is shared by all users, and updating this value affects new and existing analyses.

If you set this factor to less than one, an error message is displayed in the Status Window and the value resets to six.