Probabilistic decline analysis

This analysis provides decline forecasts for the input percentiles based on distributions of qi and b. For information on this methodology, see probabilistic decline method.

Harmony Enterprise has a default set of P90, P50, and P10, but you can set any percentile values in the Options dialog box and have between two and ten analyses created. The naming of analyses, b range, dlim, and abandonment criteria can also be customized in the Options dialog box.

We strongly recommend tailoring the b range to the reservoir and fluid when applying the probabilistic decline. The default range of 0 to 2 is most appropriate for newer wells with a short production history.

After the analyses are created (see analyzing an entity), they function similarly to a traditional decline analysis including line manipulations, exports, use in economics, etc. Analyses are created with distinct line colors, but these colors can be modified on the plot. The default colors are set for the P1 - P35, P36 - P65, and P66 - P99 ranges. Note that if you create two percentiles in the same range, they are displayed in the same default color. Point selection for best fitting and fitting the decline to a forecast are disabled for the Probabilistic Decline because these features use standard best-fitting and are more appropriate for use on a traditional decline analysis.

This analysis works with your Harmony Forecast™ license.

The Probabilistic decline analysis provides an initialization in order to create a range of forecasts for a given well. After the analyses are created, they behave as a traditional decline and do not retain information about the forecast distribution that was used to create them.

Analysis Manager pane

In the Analysis Manager pane, click the Add an analysis icon () and select Probabilistic Decline .

The decline analyses for your specified percentiles are created and each decline has its detailed parameters displayed in the Analysis Parameters pane located below the Analysis Manager pane (the default setting). These decline analyses can be linked to other analyses, renamed, and modified.

Plot Selection pane

Additional datasets can be displayed using the list in this pane. This can allow for other types of analyses to be displayed simultaneously. You can also hide any of the currently displayed datasets, though this can result in some analyses no longer displaying on the plot.

When you save a workflow, these customizations are included.

Analysis Parameters pane

For more information, see the decline analysis.