elog_curves.csv — Grubb No. 181 (API 04-111-20436) induction-electrical log, digitized from the 1972 Schlumberger scan
Depth step 0.5 ft, measured depth below KB. Runs: 1 = IES (1,828–10,142 ft), 2 = induction-neutron (10,175–11,680), 3 = DIL (11,591–13,414).

DEPTH_FT                 measured depth, ft
RUN                      logging run (1, 2, 3)
SP_REL_MV                spontaneous potential, mV, relative (no absolute zero); runs 1 and 3. Run 3 values below 12,222 ft
                         are shifted +43.3 mV to splice across the engineer's SP shift at 12,222 ft (footer: "SHIFT AT 12,222")
COND_MMHO_M              induction conductivity, mmho/m (track 3): 6FF40 in run 1, induction in runs 2–3
RES_IND_FROM_COND_OHMM   1000 / COND_MMHO_M, ohm-m (deep induction resistivity)
RES_IND_TRK2_OHMM        induction resistivity read from track 2, ohm-m; run 2 only (same measurement as the conductivity)
RES_LL8_OHMM             averaged laterolog-8 resistivity, ohm-m (track 2, solid curve); run 3 only. Shallow-reading;
                         reads below the deep induction in invaded zones
RES_SN16_OHMM            16-inch short normal resistivity, ohm-m (track 2, 0–20 scale); run 1 only. Not traced where it
                         overlaps the dashed induction curve or exceeds 15 ohm-m. The amplified short normal (0–4) on the
                         log is the same measurement at 5x and was used only as a check (agrees within 0.03 ohm-m)
NEUTRON_API              neutron, API units (track 1, 1600 left to 600 right); runs 2 and 3
QUALITY                  semicolon-separated flags (blank = traced normally):
  pulled_tight           tool stuck and jumped free (engineer's "PULLED TIGHT" notes, 15 notes, run 3). Flag covers
                         15 ft either side of each note, widened to multi-curve flat stretches. Values are not formation
                         data and depths just below may be shifted
  cond_backup_scale      conductivity above 500 mmho/m, read from the 1000–500 backup trace
  trk2_backup_scale      track-2 induction above 20 ohm-m, read from the 0–200 backup trace
  trk2_refilled          track-2 induction re-read where the first pass had blanked it
  trk2_matched_to_cond   track-2 pick chosen as the ink mark agreeing with conductivity within 1.6x (so it is not an
                         independent check of conductivity there)

Not extracted: run 1 dashed induction 0–20 and 0–200 (same tool as the conductivity); run 3 dashed deep induction
(same as the conductivity); amplified short normal and amplified laterolog-8 (same measurements at higher gain).
Blank 11,591–11,645 ft for run 3 SP and neutron (curves tangled with the run-change arrow below the casing shoe).