618 has explained it spot on. It's not just about water rates....

618 has explained it spot on.

It's not just about water rates. If it truly was 25 or even 16mD, they couldn't have dewatered the reservoir to desorption pressure while pumping conservatively. Not at this pressure and this viscosity.

The equations suggest the reservoir would be capable of something like 2000 bwd at Chiffre if the perm was 1-2mD, so the "conservative" part is that they're only pumping at 1000.

Low water rates and early gas breakthrough in an undersaturated reservoir indicate low permeability, because it shows they're dropping the pressure near the wellbore while the reservoir is too tight to recharge it.

It's possible that saturation is higher but since they measured it from bottom-hole pressure they should have the desorption pressure correct, ie they watch the downhole pressure gauge and note exactly what pressure it reads when gas starts to flow.

It doesn't mean STX got it wrong, or anything like that. They probably did measure 25mD on the DFIT - but it's like I said going way back several months now, and then several times since - a DFIT only measures permeability near the wellbore. It may be that the average reservoir permeability is actually more like 1-2mD but it's locally heterogeneous, so there are spots(like fracture zones) where it's 25mD.

That's how I see it anyway. This reservoir has surprised both me and STX before and no doubt it will do it again.