Oil IPR / TPC

An oil IPR / TPC analysis provides options to calculate and display the maximum oil rate and inflow performance relationship (IPR) for an oil well. It also provides the ability to create tubing performance curves (TPCs), which can be used to determine the expected operating point (intersection of the IPR and TPC curves) of a particular reservoir / wellbore combination. The intersection of the IPR curve with a TPC signifies the operating point of the particular wellbore / reservoir combination. For reference material, see Oil IPR / TPC theory.

Note: This analysis works with your Harmony Optimize™ license.

This analysis has the following icons in the Inflow and Outflow panes:

Delete — removes the currently selected inflow, outflow, gradient, or forecast.
Copy — creates a duplicate of the currently selected inflow, outflow, gradient, or forecast. The name is appended with the word "Copy".
/ Show / Hide — toggle between showing or hiding the inflow, outflow, gradient, or forecast.
/ Collapse / Expand — closes / opens the details for the inflow, outflow, gradient, or forecast. If you see a red triangle () in the top left of a collapsed analysis, you need to investigate the required parameters.

Inflow pane

The Inflow pane on the left-side has the following items:

Inflow — click the Add Inflow button to create an inflow that is measured at the sandface.
- Vogel — the Vogel equation is a widely accepted method for determining a reservoir's deliverability IPR. The calculation uses your information to determine the well's IPR at the sandface. This relationship between pressure and rate can be used to visually determine the desired operating pressure, or it can be combined with TPCs to compare well performance scenarios
- Custom Table — used to test points in tabular form to generate a reservoir IPR curve without being restricted to a single model. This inflow currently supports Vogel-based or Fetkovich-based curves, as well as a pure linear interpolation of input points.
Note: Your bubble point pressure is automatically imported from the Properties editor.

Plot

The plot in the center of the window has the following items:

Operating Points tab — displays a table with operating points (inflow over TPC) for a baseline, and sensitivities A, B, and C. this table is populated with the intersection points where the IPR and TPC curves touch. Note that you can copy and paste values into Excel by pressing Ctrl-C and Ctrl-V.
Auto-scale checkbox — fits the plot to the maximum viewable area of the screen.
Show Sensitivities checkbox — displays sensitized / transient inflows in the plot with a light-blue line, as well as inflows in the key-performance-indicators table below.
Inflow Comparisons tab — displays a plot of all inflows.
Plot — the plot is displayed after you type all the required parameters. Intersections on the plot correspond to the points in the Operating Points table. The axes operate in the same manner as Economics. For more information, see Y-axis icons and X-axis icons. To rescale the plot back to its original settings, double-click it.

Outflow pane

The Outflow pane on the right-side has the following items:

Pair all with drop-down list — matches all TPCs to one inflow.
Outflow — click the Add Outflow button to create a TPC. Type values or select from drop-down lists for fields in white. Gray fields are read-only. Note that all TPCs require a parent inflow and a wellbore. By default, the TPC pairs with the active inflow.

Pair all with checkbox — click this option, if you want to pair all TPCs with the inflow selected in the drop-down list to the right.

Parent inflow drop-down list — select from the drop-down list.

Wellbore drop-down list — by default, the most-recent wellbore is selected. If there is a red box around the Wellbore drop-down list, you need to correct something in the Wellbore editor.

Wellhead FP field — type your wellhead flowing pressure.

Customize Flow Path and Tubing section — click to enable this option, so you can type values for your Tubing, Annulus, Both, or Casing. Note that Gas Lift is not supported.

Liquid Ratios section — select from the drop-down list, so you can type values for your ratios.

For a given set of conditions, a TPC is a plot of the flowing sandface pressure, as a function of flow rate. This curve does not change through the life of the well. It is not at all dependent upon reservoir performance; it depends only upon the gas-liquid ratio, tubular configuration (depth, diameter), wellhead pressures, etc.

Operating Points table

The Operating Points table at the bottom of the window has the following items:

Baseline tab — your baseline key performance indicators (KPIs) are displayed over the TPC.
A tab — your "A" sensitized / future inflow's KPIs are displayed over the TPC.
B tab — your "B" sensitized / future inflow's KPIs are displayed over the TPC.
C tab — your "C" sensitized / future inflow's KPIs are displayed over the TPC.

Tip: You can view your sensitivities if the Show Sensitivities checkbox is selected at the top of the window.

Note that you can view your H₂S rates for each of the operating points under the following conditions: the H₂S% in the Editors tab must be greater than 0%, and Oil TPCs must have a non-zero gas-oil ratio. If you type a GOR value in the Outflow pane, an H₂S rate is displayed as a function of the operating-point rate. If two TPCs are paired to one inflow, both TPCs are identical, except a GOR is not used for one of the TPCs. While the H₂S column is displayed in the Operating Points table, only one of the rows has an H₂S rate that is calculated.