LGR property mapping

Important   You first have to perform local grid refinement (Local Grid Refinement > LGR Creation) before you can continue with the LGR Property Mapping form.

On the LGR Property Mapping form (model > 3D Grid > Modify Grid > Local Grid Refinement), you synchronize between level 0 and the LGR grid cell property values in selected property grids (level 0 cells refers to cells that have not been refined). Discrepancies might be present due to property editing at a specific level. Properties are upscaled from LGR cells to level 0 cells, or downscaled from level 0 to LGR cells.

To map LGR grid properties

  1. Select the 3D LGR grid.

  2. Specify the vertical range in which to apply the property scaling.

    Top surface  The shallowest K-layer included in the scaling. You can select a K-layer or a horizon, which automatically selects the K-layer of which it forms the top.

    Base surface  The deepest K-layer included in the scaling. You can select a K-layer or a horizon, which automatically selects the K-layer of which it forms the base.

  3. Select the property to scale.
  4. Select the wells to be included in the scaling.
  5. For each well, in the Distance column, set the distance around the well to include in the scaling.
  6. If the well log scaling should stop at fault planes, check Stop at fault.
  7. Select the log to be used in the scaling.
  8. Specify the LGR Settings, which are described below. In the background, the well log you select is upscaled over LGR cell thickness. The upscaling uses the same settings applied when generating the initial property model. The LGR cells that intersect the well are given the upscaled values. In this step, you select how the LGR property values are applied laterally in the model.

LGR settings

Copy  The LGR cell property values derived from the well logs are copied in lateral direction. All cells in an LGR layer within the Distance value that you set are given the same value.

Scale  The LGR cell property values derived from the well logs are copied in lateral direction, but are then scaled to match the property value of the level 0 cell to which they belong.

Example  The average (copied) porosity of the LGR cells in a level 0 grid cell equals 0.4, while the (original) level 0 grid cell itself has a porosity value of 0.44. The Scale method then multiplies the (copied) porosity values of each LGR cell in that level 0 cell by 1.1, in order to arrive at the level 0 average value of 0.44. In this way, trends in the original input model are better preserved.

Start LGR level  Set the first LGR level to include in the well log scaling.

End LGR level  Set the last LGR level to include in the well log scaling.

Synchronize between LGR levels  Select to eliminate discrepancies between property values at different levels. You use this option mainly when using the Copy option. This option deals with the synchronization between LGR cells and level 0 cells. If you have, for any reason, edited level 0 property values, make sure that level 0 is not included in the scaling, because the property values are again derived from log values and these changes might be lost.

Upscale  (Available only if you select the Synchronize between LGR level option. ) Level 0 grid cells are given the averaged property value of their LGR children cells. The level 0 cell property value might change.

Downscale  (Available only if you select the Synchronize between LGR levels option. ) The property values of LGR grid cells are scaled to match the level 0 cell property value. The level 0 property value does not change.The Copy + Synchronize Downscale function is basically the same as the Scale function.