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questions regarding X1T and X2T

Jason R

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I have a couple questions I was hoping you could answer for me:


  • Under Flow -> what is the potential drop do/used for?

  • Under Flow -> what are the left and right boundaries used for and what is the difference between open, closed and discharge?

  • Under Medium -> is the B intercept permeability? If my formation perm is 5000 MD, do I just type it under the B intercept?

    • Is the permeability supposed to be negative in this simulator or should it be positive

  • How do make the model reflect data from my sidewall core analysis(same mineralogy)

  • Can you plot permeability or skin using the XTPlot?


The goal I am trying to achieve is to basically inject my main fluid for a certain period of time, then follow that up with the 3rd party fluid(as shown in the attached file) and determine if a pressure drop near wellbore will occur due to precipitation near wellbore.

Initial 2D model.x2t

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Hi Jason,

The potential drop across the length of the domain is the driving force for flow. The program uses it, along with the permeability and viscosity, to calculate flow according to Darcy’s law. A boundary might be open to flow, closed to flow (no flow), or water might be set to enter at a specified value of specific discharge. For more information, please see 2.14 Groundwater flow, 3.2 Setting flow rate, and 4.3 Calculating the flow field in the GWB Reactive Transport Modeling Guide.

The program uses a correlation to calculate the log of permeability from the porosity, and optionally, the volume fraction of one or more minerals. Permeability is always a positive number. Log permeability, on the other hand, can be negative. For details of the correlation, please see 2.13 Permeability correlation in the same guide. If you’d like to set permeability directly, the porosity multiplier (A) should be set to 0. In your example, set B to 3.6987 mdarcy (the log of 5000). Yes, you can plot permeability in the x and y directions in Xtplot. It’s a good idea to verify that the permeability the program calculates is what you expect.

You can use a combination of equilibrium and kinetic minerals, if necessary, to define the minerals that exist in your system. For a good example, see the Weathering and Steam examples in the Reactive Transport Modeling guide (3.8 Example: weathering in a soil profile and 3.11 Example: steam flood).

In the future, please post on the main GWB forum (the front page), not the archive of old posts.


Brian Farrell
Aqueous Solutions LLC

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