ComboCurve: Type Curve User Manual
Type Curve User Manual
ComboCurve Type Curve Overview:
In ComboCurve, type curves are generated by
normalizing production and/or forecast data from a selected group of
representative wells (“rep wells”). These type curves are then used in
forecasting, development planning, and economic evaluation.
This guide outlines the supported ComboCurve workflow,
key settings, and common pitfalls.
1. Key Concepts:
Production vs Forecasts
- Type curves can be built from:
- Production only
- Forecast only
- Production + Forecast
- Inclusion of wells is controlled by Well Validation Criteria.
Important System Behavior
- Type curves reference a forecast, but do not store volumes independently
- Clearing or deleting forecasts can remove wells from eligibility if validation criteria are not met
- Certain exports and bulk operations require workarounds (documented below)
2. Prerequisites:
Before creating a type curve, confirm:
Wells
- Wells have:
- Production data or
- Forecast data or
- Both (depending on validation criteria)
- First Production Dates are populated correctly
- Lateral lengths and attributes are accurate
Forecasts
- A forecast exists if required by validation criteria
- Best practice is to use a duplicate forecast for type curve generation
Note: Deleting forecasts from an active forecast removes wells entirely from that forecast.
Use Clear Well Forecasts on a copied forecast instead.
Creating a New Type Curve
1. Navigate to Type Curves
· Go to Type Curves
· Click Create Type Curve
2. Configure Type Curve Settings
Define:
· Type Curve Name (Example: DEL_WCC_12)
· Select Forecasts or use Production Data (e.g., Wolfcamp Well Forecast)
· Fit Type Choose Rate or Ratio
· Data Type (e.g., Monthly, Daily, Whichever Used to Generate Forecast)
· Well Validation Select whether to include wells
with production data, forecasts, production data AND forecasts, or production
data or forecasts to be used in the type curve generation
Warning: If forecasts are cleared
and the criteria require Production AND Forecast, wells will be
automatically excluded from the type curve.
Selecting Representative Wells
1. Apply Filters
Use filters to select wells with
similar characteristics
Examples:
· Geology
· Completion design
· Lateral length
· Development timing
2. Filter from Map
Just like with forecasts and importing, we can filter from a
map using the polygon tool or the radius tool
Review Rep Wells:
Once the Type Curve section has been created, this is a
great time to use ComboCurve’s plots to view rep wells and further exclude
outlier wells. In the drop-down menus of the 4 graphs, you can select from a drop-down
list of many powerful plots.
Here, we can use Shift+Click to lasso wells or Alt+Click to
box wells to either include or exclude in our type curves.
Notice the wells selected here are greyed out, and we can
choose in the dropdown menu whether to exclude, include, or only include these selected wells. You can also select via the colored dots which phases
specifically you are making changes to. This way, you can exclude wells whose
oil production may be an outlier, but keep those wells' gas/water phases.
Lastly, you can change between the different phases you are
viewing easily with the phase drop-down menu.
Normalization:
Once we have the wells selected we want to use for our type, we can determine whether or not to normalize our data. Normalization is great
for further narrowing our data based on a well's characteristics. Here in the
Normalization tab, we can choose normalizations for each different phase
independently and choose different well characteristics.
ComboCurve offers 4 normalization models:
· Linear Fit
· 1-to-1 Fit
· Power Law Fit
· 2- Factor Fit
More information defining each can be found in the knowledge
base article: ComboCurve: Normalization and ComboCurve: 2 Factor Normalization Documentation. You can select which of these fits in the drop-down menu for each phase.
For this workflow, I notice that there is a decent trend
between my EUR and Perforated Lateral length, which I can see in one of the
plots. So I have determined that a linear normalization should be a good fit
for this set of wells.
Selecting the Linear Fit here will add that linear fit to
the graph. For this workflow, noticing the stock linear fit may be overly
affected by those higher producing wells as seen by a discrepancy in the number
of wells above and below our linear fit. Here we can do two things:
1. Combocurve allows us to change our fit parameters directly on the fly, adjusting our fit
2. As mentioned before, we can also exclude more wells that we deem outliers
I will choose the second option because it is as easy as Alt+Click, and excluding these overperforming wells. After excluding more outlier wells and refitting my Linear fit, my graph now looks like this:
Now I have a much better fit, ensuring my resulting Type
Curves won’t overestimate our production.
Lastly, before we calculate our Type Curves, there are two
really important things to remember:
1. Don’t forget other phases
- A
common issue is creating a type curve and not normalizing the other phases to a
characteristic.
- When
applying type curves to PUDS of different characteristics (i.e., Perforated
Lateral Length), if there is not a normalization applied to all phases for that
characteristic, we will not see volumes for the other phases
2. Make sure to toggle the Normalization button
- Toggling this one tells ComboCurve to use our normalization parameters when creating our Type Curves and offers a quick way to compare with and without a normalization
A quick way to normalize all the phases, assuming the same
normalization, is to check the Copy Settings to All Phases button.
Once you have selected your normalization, you must save it.
Simply after running the normalization, click the Save button at the bottom.
Another good diagnostic check to make sure your
normalizations are actually working is checking their multipliers in the table.
Here, I can look through the list of wells and see the exact multipliers the
normalization has applied to the production based on the linear fit in this workflow.
So here I can see that my well “FEZ FEDERAL COM #704H” is
getting an EUR multiplier of 0.598, which suggests that this well was one of the
ones performing over my linear fit.
Here, I can confirm by hovering over the data points in
the chart showing me the name of each well.
Generating the Type Curve
Once we have navigated through the normalization and removed our outliers, it is finally time to calculate our Type Curves. In the Fit tab, we are provided a drop-down list with commonly used segments for DCA.
Here you can select which of these you would like to use to shape your type
curves.
For this workflow, we will use the “Exp incline + Arps + M
Arps (Non-Smooth)” just for example. Notice again, here you can change the DCA
segments and parameters for each phase by scrolling down. Finally, running a fit
is as easy as clicking Run.
A common issue we see here is you click run and nothing
pops up. The most likely victim is that the settings on the graph is set to
only show the background well’s data. You can easily fix this by navigating to
the graphs setting button and deselecting Show Background Only.
Noticing in this settings you can also do a bunch of other
helpful things like show the excluded wells, change ratio to rate, data
resolution, and in the Adjust Series tab you can select which functions appear
on the graph individually.
Again like before with the normalization, it is important to
save our normalization.
Validating Type Curves:
Once we have our type curves there are metrics we can look
at within ComboCurve to evaluate the curves' fit to our production data. Like
before, we can change the graphs to different charts and derive conclusions from
them. For example, looking at the EUR distribution with our added Type Curve.
Our Type Curve’s P10, P50, and P90 compared to our wells' average P10, P50, and
P90 appear to look satisfactory at least for the scope of this example.
Manual Type Curve Adjustment:
Like with forecasts we can visually adjust the Type Curve’s
fit using keyboard shortcuts on the fly. This can be done in the Manual tab
and the list of Keyboard Shortcuts can be found at the top right.
Unlike the forecast section, though there is a Save button
here, so feel free to move and play around with it and hit reset to return back
to the generated type curve. However, once you hit Save you won’t be able to undo
the changes unless you rerun the type curve calculations using the same
parameters.
In the dropdown menu, you can change the background figure.
You can also add/remove segments, change the duration of the curve and q final
values, and most importantly, individually change each segment as you please, either using the keyboard shortcuts or manually changing the curve's values.
Applying Type Curves:
Once we have our type curves, we may want to apply them to
PUD wells as a forecast for production. This is a very helpful workflow because
we can use our offset wells to predict PUDs wells production.
1. Creating PUDs:
Creating PUDs is super easy and there are two ways to do it
depending on your specific workflow.
The first way is simply by creating new blank wells in
Combocurve. This can be done from the home screen -> Project Wells ->
Create Wells:
Here it will give you the option to name the wells, select
the number of wells, and the number of wells per pad. You can also choose which
headers to add to these wells. For this example, I will create 3 wells and add
the lateral length header with a temporary value of 6,000 ft for now.
To get a better view you can go to the Review tab and see
these new pads in table form. You can also directly edit the wells' characteristics here as well by selecting the “edit” button on the top right.
For this example one pad will have a perforated lateral length of 4,000 ft ,
6,000 ft and 8,000 ft.
Once I have created these
wells, I can filter to them, in this case, I will search by well name to well
names containing “PUDS” to confirm they were added successfully.
This first way is super easy if you have a few wells or want
to just mess around with changing a wells characteristics. You can also import
PUDs which is the second way. This is done the same way as importing wells,
just these wells won’t have production data. This is helpful to mention because
you may be getting an excel file with a list with a lot of PUDs with more
headers filled out like geographic location etc. But for this example we will
stick to the simple generic wells we created.
2. Forecasting PUDs
The goal in this workflow is to apply our type curves as
forecasts. The first step after creating our PUDs is to navigate to the
forecast and create a new one filtering to our PUDs. Note if you need a
refresher on how to create a forecast please refer back to the Forecast Manuel,
the process will be the same.
Once you have created your forecast and filtered to your
PUDs, you will notice there are no curves. That is expected because we have yet
to apply our type curves as our forecasts. To do this simply navigate to the
Forecast Options then select apply Type Curves and select the Type Curve you
choose.
Once you have selected your Type Curve and clicked apply,
close out of this tab and observe the forecasts for each PUD well.
Just like that we have applied our type curve to our PUD
wells as forecasted production.
3. Normalization Applied to PUD Wells
However we aren’t done quite yet. Notice in the last figure
how each PUD well’s forecast is exactly the same even though we have defined
different lateral lengths? This can be done extremely easy by applying the type
curve again, however this time selecting the Normalization button.
Now notice how the EUR increases as our perforated lateral
length does as well. Here it is applying those same normalization we defined in
the type curve menu to our PUDs, and applying multipliers to their production
data based on lateral length.
This is where it is important to make sure you have defined
characteristics for the PUDs that you are normalizing over for all phases. If
you do not have defined normalizations for each phase or are missing in this
example specifically perf lateral length for each PUD you won’t see forecasted
production. This is a common mistake that is made when forecasting PUDs.
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