Well Index Calculation for Well–Fracture Intersections

[Calvin Scott]

Dear all,

I hope this email finds you well.

When calculating the intersections between wells and fractures (including both natural fractures and hydraulic fractures), I need to compute the well index (WI) separately for the well–fracture intersections. However, I found that computeWellIndex.m does not include such calculations. I also could not find any script corresponding to Equations (10.10) and (10.11) in the textbook <Advanced modelling with the MATLAB reservoir simulation toolbox>.

May I ask which script contains the implementation of these calculations?

Thank you very much for your time and help.

  Kind regards,  

[Olav Møyner]

Hi Calvin,

Equation 10.10 corresponds to line 41 of computeWellIndex: https://github.com/SINTEF-AppliedCompSci/MRST/blob/fd5cea5d2f9180331150131aabdfb8b34c045cc1/core/utils/computeWellIndex.m#L41

Equation 10.11 is found a bit later in line 54: https://github.com/SINTEF-AppliedCompSci/MRST/blob/fd5cea5d2f9180331150131aabdfb8b34c045cc1/core/utils/computeWellIndex.m#L54

The code itself does not compute well indices for fracture intersections since MRST does not have a unified fracture model, but rather several different implementations.

Hope this helps,

Olav

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[Liu, Jon (he, him | il, lui)]

UNCLASSIFIED - NON CLASSIFIÉ

Hi all,

 

   Does MRST include functions to assign permeability to a refined grid, e.g. refining a fine grid to coarse grid with similar rock property (mean values or interpolated..) or reverse..

 

Thanks a lot,

Jon

[Olav Møyner]

Hi Jon,

There are in fact a lot of functionality for this in MRST. In the code, it is usually referred to as upscaling.

For more details, you can see the first MRST book (free as open access here: https://www.sintef.no/projectweb/mrst/publications/mrst-book/) under chapter 15 “Upscaling petrophysical properties”. The examples from this chapter are included in the book module and the upscaling module.

Best regards,

Olav

[Calvin Scott]

Hi  Olav,

Thank you again for the previous explanations. I have a follow-up question regarding EDFM in a 2D setting.

I am currently working with a 2D matrix grid and would like to introduce natural fractures modeled as EDFM line fractures. The physical dimensions of the model are set as
physdim = [320, 140], without a Z-direction.
The main reason for using a 2D matrix grid is to reduce computational cost, since the flow simulation will later be coupled with geochemical reactions. In my case, a full 3D matrix grid would make the coupled simulations prohibitively expensive.

My question is related to well–fracture intersections:

In a 2D matrix grid with EDFM line fractures, is it possible to compute well–fracture NNCs when a well intersects a fracture?

From my current understanding:

• Conventional EDFM does not explicitly handle or compute well–fracture NNCs.

• Such treatments are typically introduced only in pEDFM.

• In MRST, the existing pEDFM implementations appear to be mainly designed for 3D grids, and they rely on the function wellfractureNNCs3D.m.

Given this, I am unsure whether there is a feasible or recommended approach to handle well–fracture intersections and the corresponding NNCs within a 2D matrix grid using EDFM line fractures.

Any insights, references, or suggestions would be greatly appreciated.

Best regards,
Calvin

[Olav Møyner]

Hi,

The most natural solution is to simulate a 3D grid with a 1 cell thick layer. A 2D setup is similar to this, assuming unit (1 m) whenever z differences are needed.

Best regards,

Olav

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From: sinte...@googlegroups.com <sinte...@googlegroups.com> on behalf of Calvin Scott <kungcli...@gmail.com>

Sent: Wednesday, January 7, 2026 15:10
To: MRST-users: The Matlab Reservoir Simulation Toolbox User Group <sinte...@googlegroups.com>
Subject: [MRST Users] Re: Well Index Calculation for Well–Fracture Intersections

 

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