Caprock integrity analysis

Caprock integrity analysis (model > Fault Stability > Caprock Integrity) aims to reveal the proximity of high risk threats to caprock stability. It uses a calculation that takes into account all neighboring pressures to derive the principal and least effective stresses when determining the orientation on which the fault stability analysis parameters are calculated. This allows for a more thorough analysis as pressure communication is captured by considering not only the local pore pressure, but all neighboring pore pressures. The result of the analysis is a pair of properties that show the proximity of critical fracturing to the caprock.

Prior to performing the analysis, you need to have the required geomechanical properties available on the 3D grid. The three properties that need to be available are: pore pressure, SP1 and SP3. Use an available 3D grid or create an Easy Grid through model > 3D Grid > Create Easy Grid. For mapping 3D mesh data to the 3D grid, use the Property Mapping Tool under the Tools workspace.

Important   Node and element properties cannot be mixed when mapping properties from the 3D mesh to the JewelGrid. Make sure that all three properties have the same amount of time steps and that the mapped properties used the same time step (you can check this in the Property Inspector located under Workflow > Panes > Inspector). Rejection of the input will occur if these conditions are not met.

To run caprock integrity analysis

  1. Select the JewelGrid on which the pore pressure, SP1 and SP3 have been mapped.
  2. Specify the pore pressure, SP1, and SP3 properties from the grid.
  3. Under Select the reservoir, select a discrete property that defines the reservoir, e.g. a ZoneID property.
  4. The decrease in vertical fluid flow can be accounted for in the analysis by checking the Use density correction box. A value for the fluid density can then be specified.
  5. Specify the vertical and lateral distances to search for in the analysis. The vertical distance searches in the downward direction.
  6. Under Friction coefficient, define a friction coefficient in order to assess the activation of existing fractures. The Mohr-Coulomb criterion is used here, based on a cohesion of 0 along with the friction coefficient you specify.
  7. Optionally, you can choose to generate a point set representing the results of the analysis. The point set will be added to the Data folder in the JewelExplorer.
  8. When using properties with time steps you can choose to analyze only the active time step instead of all time steps. This option is activated by default.
  9. Click Apply to run the analysis and keep the form open or click OK to run the analysis and close the form.