In last week’s well (10,640–11,180 ft), our CMR-Plus T2 spectra were cleanly bimodal under OBM while density–neutron was compromised by washouts, so I settled on a 33 ms cutoff after tying to MDT mobilities and six plug NMR runs. That moved FFI from 7% to 12% and brought Coates perm within about 0.2 mD of core. How are you selecting cutoffs and QC’ing the inversion when OBM filtrate and temperature drift bias the short-T2 population?
I set the cutoff where the T2 geomean matches Swi from core capillary pressure, then QC by re‑inverting the CMR‑Plus with a lower OBM filtrate diffusion value; if FFI shifts <1%, the ‘33 ms’ holds. On your 10,640–11,180 ft pass, watch a 5–10°F temp creep — I’ve seen the long mode slide a few ms and make Coates about 0.1–0.3 mD optimistic. Small caveat: if TE was >0.3 ms you’re losing sub‑ms bound water and biasing the cutoff high, @OP.
Quick example from last month under OBM: I reprocessed the CMR‑Plus at two echo spacings (0.6 and 1.2 ms) and nudged the cutoff until FFI was essentially “TE‑invariant”; once that stabilized, Coates k was within about 0.2 mD of core and the oil peak sat safely long‑T2. Small caveat, @OP: in vuggy streaks that test skews low, so I cross‑check with MDT Vx viscosity at P/T before I lock the cutoff.