Quick one: in shale frac simulations, what’s had more impact on modeled EUR for you — matrix porosity tweaks or effective leakoff (Carter C) changes? In a 400k‑cell SRV case last week in tNavigator, doubling C while holding fracture conductivity constant shifted EUR about 3%, whereas a 20% porosity bump moved it about 9%; curious if anyone sees the opposite in tighter systems.
In my ultratight cases, porosity is the pantry and leakoff is the leaky faucet — EUR tracks porosity unless ‘water block’ is modeled. Try calibrating C to DFIT/minifrac and turn on multiphase leakoff (Sw_init/kr/pc); C’s effect jumps once water blocking is in play — does it still sit at about 3%?
Try making leakoff pressure‑dependent instead of a flat “Carter C” and enable Pc(Sw)+two‑phase cleanup; when I do that, doubling C has bumped EUR about 8–10% in about 40 nD rock, otherwise porosity still wins. Are you running Pc/kr cleanup or just single‑phase?
On gas-heavy shales, once I enable Langmuir adsorption and a pressure‑dependent matrix perm (PVDK), leakoff starts to move EUR more than a straight porosity bump because cleanup and desorption kick in — adsorption’s the piggy bank you only crack after C drains the water… Quick step: in tNavigator, add a modest PVDK curve and Langmuir, then re‑run your C‑doubling and a 3–5 day shut‑in; I’ve seen the C sensitivity jump from about 3% to about 8–12%. @ian_swift99 does that line up with your pressure‑dependent take?
And i’ve seen porosity win too until I swap to imbibition relperms and nudge Swc up a couple points — then a 2× C moved EUR about 8–11% in about 50 nD rock because cleanup drags. Quick tip: clone your case with imbibition curves and cap early flowback drawdown (keep steps <150 psi for 12–24 h) to see if C overtakes phi. @ian_swift99 does that track with what you’re seeing?