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  • Writer's pictureNicholas Harvey

Proposed Image Textural Study

HRP currently has over 50 wells in the public domain in the Cooper-Eromanga basin and is seeking participant oil and gas companies to commit to a multi well textural image study of the wells in the basin. The wells with image data will be provided under license to interested parties as part of the deliverables. The study will include the following:

  • Processed borehole image data set

  • Log Analysis of open hole logs with the principal aim of calculating porosity

  • Computation of textural properties for formations covered by the images which will include depth indexed

  • Pore Throat average distribution

  • Permeability Distribution

  • Porosity Distribution

  • Surface area Conductivity Distribution

  • Grain Size Distribution

As indicated, the data will be licensed for each well as two files. A 6 inch sampled data set and a 0.1 inch sampled data set. This data will be provided as DLIS files as it contains arrays. An abbreviated LAS file containing the averages of the above outputs at 6 and 0.1 inches will also be provided. HRP envisages that the study will take approximately 6 months to complete.

An example of the products produced are shown in the graphic below:

The tracks are as follows. Click on the plot to open a PDF

  1. Gamma Ray

  2. Depth

  3. Borehole image (static) - The green curve is RT from open hole whereas black is image derived RT

  4. borehole Image (dynamic) - The green curve is RT from open hole whereas black is image derived RT

  5. Open hole resistivity curves

  6. Density-neutron curves

  7. Fracture modulus as colour infill for UCS

  8. Maximum permeability azimuth

  9. Recomputed sonic and density from conventional analysis model

  10. Shale gas

  11. Rock Moduli

  12. Conventional deterministic model

  13. Image Porosity 0-0.25

  14. Image Perm - horizontal, vertical and maximum horizontal plotted 0.0001-10 MD

  15. Image pore throat distribution - 0.0001-10 uM

  16. Surface area conductivity - more conductive to left less conductive to right

  17. Saturation from image calculated using Indonesia equation and porosity, RT from images

  18. Grainsize distribution

  19. Net and Pay flags

  20. Lamination index

  21. Sorting.

A quick review of the data is shown in the cross plots below. The first cross plot shows the surface area conductivity on the x axis and the pore throat on the y axis. It shows that the more permeable and higher surface area conductivity rocks have larger pore throats. The surface area conductivity suggests these rocks are oleophobic whereas the smaller pore throat size rocks are hydrophobic.

The second cross plot shows the grain size on the x axis and the pore throat on the y axis. It shows that the more permeable and larger grain size rocks have larger pore throats. A comparison with the cuttings and side wall cores from this well shows a good match in grainsize.

The maximum horizontal permeability azimuth shown in track 8 gives an idea of the permeability orientation. This is an interesting measurement as it can be compared with fractures, cleats in coals (Epsilon Formation for example) and other features that cause directionality in permeability.

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