PNG 440W: Formation Evaluation
Due in class, at 8:00 am on Thursday, October 23rd, 2014. Total points 100, grade weighting factor 3%.
The litho-density log on the following page was logged in a borehole with freshwater mud and assuming limestone lithology (noted by “_LS” in legend at top of porosity track).
For the layer from Zn_A to Zn_B, correct the average density porosity. The steps for doing this are: 1.) Estimate an average porosity value for this layer (should you use PHID or PHIN curve?) 2.) Calculate bulk density based on what the logger assumed the lithology was 3.) Determine actual lithology from PE curve (using, for example, Table 5-2 in Dewan) 4.) Calculate new, corrected average density porosity
How does your new porosity value compare to the old one with respect to agreeing with the average neutron porosity value?
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