G. Gridding

Owned by Erlend Kvinnesland
Last updated: Sept 23, 2013
3 min read

Introduction

Grid models are essential in modeling reservoirs. Good grid models require good input and well tuned algorithms.

In this section we will use seismic interpretation lines and closed stick faults as input. There are seven interpretation sets including the seabed. The reservoir has six horizons. The bottom five have fault lines as input while the top one does no have any faults.

Exercises

 

 

The exercises in the next few chapter are done on the Course B1 project, but if you want you can copy the relevant data over to your own project.

 

 

Exercise

Grid a time surface from seismic interpretation

  1. Display interpretation lines from 02_Time data / Interpretation lines / 02BasePliocene.
  2. Right click 02BasePliocene and go to Gridding > Simple points and lines gridding
  3. Set the Grid Window to: xmin = -188000, xmax = -47500; ymin = 7864500, ymax = 7959000

  4. Set X and Y increment to 500. (the grid should have 282 rows and 190 columns)

  5. Check in Apply reference grid or outline and browse in: 01_Cultural / Boundary border_line
  6. Use gridding algorithm Parabolic (default).
  7. Check in for Use two gridding steps. Grid increment will be automatic calculated if blank.
  8. Set moving average as gridding algorithm for 1. step.
  9. Click Execute. The result will be written to the same folder and displayed.
  10. Click OK (this will save the panel with all parameters)

  11. Create a new folder called Interpretation grids and cut/paste the result grid into this folder.

 

 

Exercise

Advanced grid display

  1. Clear your screen and set Geocap in 2D mode
  2. Right click your grid and select Additional Display > General display
  3. Check and select Color bands in the left section.
  4. Under Contour levels set Number of levels to 10
  5. Check Draw contour lines
  6. Click Execute
  7. On the Toolbar click the icon and the click on your grid in the graphics window
  8. In the dialog that appears drag the Opacity slider to about 60% and click Close
  9. Right click your grid again and select Additional Display > Color legend
  10. Display the interpretation lines and border line also

Your graphics window should now look similar to the image below.



Pliocene grid with interpretation lines and boundary

 

 

Exercise

Grid a time surface with closed stick faults.

  1. Display 02_Time data / Faults / 07SilurianFaultInt_Polygons. This is how the fault polygons comes from Kingdom.

    To be able to use these fault polygons in Geocap we need to edit them to remove the blobs. This can be done using the Edit points and lines command.
    Howvever, to save time we have already created an edited dataset that we can use now called CorrectedClosedFaults

  2. Clear your screen and display the correct edited fault lines in 02_Time data / Faults / CorrectedClosedFaults, and notice the difference.

  3. Right click 02_Time data / Interpretation lines / 07Silurian and select Gridding > Gridding points, lines and faults.
  4. Don't alter type of input data (under development). Use default: Single points.
  5. Set the Grid Window to: xmin = -188000, xmax = -47500; ymin = 7864500, ymax = 7959000
  6. Set the X and Y increment to 500.
  7. Click Calculate to get number of elements in rows and columns: 282 x 190.
  8. Go to the Fault Input tab.
  9. Check in Closed stick faults and browse in: 02_Time data > Faults > CorrectedClosedFaults
  10. Clik Test at bottom to do the blanking test. The fault polygon should be filled inside. No lines outside.
  11. Go to the Grid options tab.
  12. Check in Use reference grid or outline and browse in: 01_Cultural > Boundary border_line.
  13. Check in Use two gridding steps.
  14. Go to to Result Grid tab.
  15. Set the saving option to Save in project. The result grid will be saved in the same folder as input unless another folder is browsed in.
  16. Click Execute
  17. The faults lines have been assigned z values and are located in workspace as closedGenFaults. Transfer them to the project using: folder > New > Workspace Data > closeGenFaults.
  18. Click OK to save the grid panel.
  19. If time, repeat the procedure for all faulted horizons. If not use the data in the course project.


Silurian grid with faults and input lines