How to enter DCA parameters onto the Analog table of the Production Forecast form

The analog table of the Production Forecast form contains the mathematical declines (or inclines) for the phase instances. These create the production used in forecasts. The available input varies with the DCA Type. The user can input various combinations of the available parameters to create valid analogs. This presentation discusses the parts of a forecast, walks through the displayed variables and input a simple exponential decline.

Randy Strauss
28 steps
2 minutes

One of the first things to under stand is the interaction of history and forecasts in R3. This is an illustration of this interaction. The As Of Date (Graphics) which is the same as the Production Start Date (Economics) defines what part of analog forecast, smooth lines, will be used as remaining production in an evaluation. Beyond the As Of Date is this remaining production. The historical production, erratic up and down lines, before the As Of Date is summed as the prior production. Sometimes the As Of Date is later than the end of the history. In this situation an analog, such as a curve fit, that extends earlier than the As Of Date will be used to provide the historical production, Back-Forecast yellow block, for this gap.

Select the Production Forecast form tab and observe the Analog Production table.

Moving from left to right, the first column is the Name. This column shows all the defined phase instances. This column is not editable.

To the right is the DCA Type. When selected this column display a drop-down list of common mathematical formulas such as exponential and hyperbolic.

The Unit shows a rate unit which also indicates the production unit for volumes. Eliminate the denominator. Right -click the Unit of an individual analog to display the pop-up menu. The unit rates are stored in corresponds to the Scenarios processing type. Exact will use a per day unit and Average will use a per month unit. However various units are available to be displayed.

Next is the b factor. this is used by hyperbolic analogs to define the rate of change of the slope for forecast.

The Dei is the effective instantaneous decline of an analog. Observe that it is entered in a percent.

The Start Date of the analog by default is a reference, indicated by the green color, to the Production Start Date. A curve fit by Graphics will set this date to the first active historical point.

The qi is the flow rate at the Start Date.

The qf is the flow rate at the End Date.

The End Date is the termination date of the analog as one would expect. This value is often a calculated value as indicated by the the grayed input field. Try not to be confused by the alternating dark and light striping of the analog table.

The Dend is the decline at the analog's termination. An exponential's decline rate is constant therefore do not expect the value to be shown.

The Dmin is used by Modified formulas such as the Modified Hyperbolic as an indicator of when to switch to an exponential.

The Seg. REM is the total production from this analog segment for the phase instance.

The Prior Cum. is the historical summation to the Production Start Date of historical production and any back forecast.

The REM is the portion of the production generated by the analog that falls on and beyond the Production Start Date.

The EUR is the summation of the Prior Cum. and the REM. Either the REM or the EUR can be input. Inputting the EUR will cause the REM to be the calculation of the EUR minus the Prior Cum. And the REM will become the editable value while the EUR will be considered the calculated value, i.e. grayed out.

This example is using a child Asset of the Brown-Slaughter Asset.

The Data Start Year is 2023, the data End Year is 2100 and the Production Start Date is January 1, 2023.

The analogs in the parent Asset have had their inheritance to children blocked.

Using the gas1 analog, right click on the Unit MCF/day. On the pop-up menu select Monthly. this will display a menu extension. Select MCF/month. The Unit selection does not change the Scenario processing. The input will be converted to match the process but be displayed in the selected units.

The DCA Type was left as EXPONENTIAL so there no input for the b Factor. In fact it will be grayed out. Select the Dei input field.

Type "15" for the decline percentage and select the qi input field.

Type "1000" and press the enter key. Select the End Date input field.

The qf could have been entered and the End Date would have been calculated. But for this example type "dec 31 2060" and press the enter key.

Observe that the Seg. REM, Prior Cum., REM and EUR are all calculated.

Tip! The analog parameters can be adjusted to enhance or tune the analog decline.

To change an input value, right-click on the input.

Select Clear Value and input the new value. If Remove Definition is selected the entire analog including its multiple segments will be remove with the option of removing any scheduling in this phase instance's Digital Production stream.

Alert! The Analog Production and Digital Production is additive.