Gassmann Fluid Substitution

Description Calculate new density, P-velocity, and S-velocity curves using the Gassmann Equation.
Module(s) Explorationist
Requirements
Related
Works with

This process calculates new density, P-velocity, and S-velocity curves using the Gassmann Equation. Gassmann is an equation to derive P-velocity, S-velocity and density in a rock medium in which the original fluid was replaced by another fluid (fluid substitution).

  1. In theControl Panel,go to View  New Single Well View.
  2. In the Single Well window, open theProcesstab.
  3. At the tab header, click theblue "+" icon.
  4. ClickGassmann Fluid Substitution.
  5. Type a name for the process and clickOK.

Configure the Gassmann Fluid Substitution process

  1. Input
    1. Curves:
      1. Velocity type:
        • Velocity: Select to calculate from velocity curves
        • Slowness: Select to calculate from sonic logs (slowness)
      2. Select the required curves
        • P Velocity or P Slowness
        • S Velocity or S Slowness
        • Density
        • Porosity
  2. Reservoir interval: Set the Start and End of the interval over which to perform the fluid substitution. For each boundary, select the reference type from the dropdown:
    • Depth (MDKB), Depth (TVDSS), or Depth (TWT): Enter a depth value directly.
    • Horizon: Select a horizon from the project. The depth is derived from the horizon's intersection with the well.
    • Marker: Select a marker (well top) from the well.
  1. In situ fluids:.
    1. Reservoir type: Specify the in-situ fluid expected in the recorded well data.
    2. Saturation: Specify the expected in-situ saturation (in percentage, %) of water and the specified fluid that is expected in the recorded well data.
  2. Fluid properties: Specify the properties (density and bulk modulus) of each fluid to match recorded well fluid properties.
  3. Matrix properties:
    1. Rock Type: Select the basic rock type for use as the mineral matrix. This should match the estimated well lithology.
    2. Density: Specify the density to be used for the selected rock type.
    3. Bulk modulus: Specify the bulk modulus to be used for the selected rock type.
  4. Substitution fluids:.
    1. Reservoir type: Specify the replacement fluid.
    2. Saturation: Specify the replacement saturation (in percentage, %) of water and the substitution fluid.
  1. Output
    • Curves
      • Enable custom name: Specify the name of the output curves. Each curve will be named as "[output class]_[process name]" by default, or if a custom name is supplied, "[output class]_[custom name]".
      • Extent: Specify the extents of the output curves.