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How can the relationships between permeability (k/k0) and porosity (Φ/Φ0 ) in the fault be changed?

I am using ECO2N to simulate CO2 leakage in a geological formation with a fault (See the fig). I need to apply different relationships for permeability (k/k0) and porosity (Φ/Φ0) between the fault and the formation. Can TOUGH handle this operation? If so, how can it be implemented?🙂

4 replies

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    • Reservoir Engineer
    • Alfredo_b
    • 2 mths ago
    • Reported - view

    In TOUGH2-ECO2N, as in EWASG, parameters for k/ko vs phi/phio are given under block SELEC and are used for all the rock domains specified under block ROCKS. The same seems to be done in TOUGH3.

    To be able to use different k vs phi relationships for different rock domains, the reading of related parameters shall be allowed under block ROCKS. Needed modifications are simple, but the source code needs to be modified. 

    Regards,

    Alfredo

      • xusheng_chen.1
      • 2 mths ago
      • Reported - view

       Thank you for your valuable suggestion! Fortunately, I have the source code, but I am not very familiar with it. If possible, could you tell me which parts of eco2n_v3.f or other source files I should modify? I will try it out. Thanks again for your advice.

      • Reservoir Engineer
      • Alfredo_b
      • 2 mths ago
      • Reported - view

       As you posted under TOUGH2 I assume you are using TOUGH2-ECO2N.

      k vs phi model is assigned using IE(11) and model parameters are given with FE(1) and FE(2), all under block SELEC for all grid elements. These parameters need to be assigned based on ROCKS domain. The easiest way is to employ unused locations under ROCKS block. Under ROCKS 1.1, locations 6, 7 and 8 could be used.

      6 and 7 are used for XKD3 and XKD4 for EOS7R only, while location 8 is not used.

      You should add an array to store corresponding values for IE(11), FE(1) and FE(2). it should be   dimensioned for MNMAT (number of ROCKS domains). The array should be included in a COMMON shared by subroutines INPUT and RFILE and function AKREL

      The index of ROCKS domain (NMAT) for the current element in EOS  shall be passed to function AKREL using an additional COMMON.

      Then AKREL shall be modified by using the parameters in the new array to replace the original SELEC parameters.

      This is a possible approach. Looking in detail you may find a better way.

      Regards,

      Alfredo

      • xusheng_chen.1
      • 2 mths ago
      • Reported - view

       I really appreciate your valuable advice, it's very helpful to me. I'll give it a try, and if there's any progress, I'll be happy to share.

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