Core-Log Shift-Search (Depth Correction Estimate)

Companion to the depth-misalignment QC test: for each core run identified as mis-aligned, an estimate of the depth correction is determined by 'sliding' the core samples against the log and finding the best-fit alignment. Uses lab-measured core porosity against density-log-derived porosity due to the absence of conventional core-gamma-ray tie data -- digitised core gamma-ray curves are not available in the source data (where present at all, they exist only as scanned images in report enclosures).