The APB Analysis Tab

This tab allows the design engineer to perform Annular Pressure Buildup (APB) and Wellhead Movement (WHM) calculations for a given thermal calculation, such as Production or Worst Case Discharge thermal simulations.

When performing APB Analysis within StrinGnosis, we recommend that you have the “Sidekick” open to the side of the window or on a second monitor. If you haven’t already, make sure to right click and check “Show Annular Labels” which will then relate to each Annulus that you will find inside of the APB Module.

The next steps are as follows;

  • Name the APB Case
  • Set the Initial Temperature
  • Set the Final Temperature
  • Check the box for “Wellhead Movement Calculation” if you need to, this is optional
    • If you checked this option, make sure the calculations below are as close to accurate as possible

Once you’ve complete these steps, you will find each the Annual Labels at the top and in the video you will see that it goes from A to E. By default each of the Annuli is sealed but as shown in this example video, the D annulus could be subject to Leak Off so we selected the option; “Leak-off at minimum fracture pressure”. The Fracture Gradient that now becomes available automatically populates from the Sidekick.

Again, in this example, Pete was trying to identify where to leak-off but there was a possibility of Annulus E being in the salt zone. To check, Pete created a copy of the original APB case, renamed the copied case to identify “Leak-off”  and selected the Annuli that he wanted to test. To check the TVD/Layers Below Depth, he clicked “The Well” on the top of StrinGnosis and then “Formation Data”. On this occassion decided it was unlikely to leak-off as it was in a salt zone.

To do a comparison between the two APB cases created, go back to the tab “APB Analysis” and click on one of the cases, hold “CTRL” and click the other so they are both highlighted. Above the case names, click “Calculated Selected Cases”. To the right hand side you wil notice the “APB Results” tab and the “Comparison” tab. If you want to refine the data shown in the comparison tab, just below the tabs click “Show/Hide Data” and select what you need.

If you need further support when using the APB Analysis, click the “Help” button on top right hand side of StrinGnosis, where there is a lot more information.