Icharus,I am using sub horizontal boreholes +/- 20° from...

Icharus,

I am using sub horizontal boreholes +/- 20° from horizontal.

I just cast a glance at Hartshorne, it will surprise you but it backs my results.

Horizontal wells drilled in this basin cross between 2000ft and 3000ft of net coal, whereas in Fols 2 according to release 433 m (1420 ft) of coal were drilled.
I have therefore recalculated the flow rate at Folschviller with a 2500 ft drain. It is 13 900 scftd.

The permeability of coal at Lower Hartshorne at 1500 ft is good (30 md), but permeability in coal decreases quickly with depth as per an exponential law. At 2500 ft it could be 0.3 md and 0.003 md at 4500 ft.

I expect that in-situ permability of coal at Fols (2500 ft) will be about 0.3 md.
At 30 md, the flow rate would be 13 900 scftd x 100 = 1.39 mmscftd, pretty close from the values of Hartshorne.

The difference in productivity mainly reflects the change of permeability with depth. If you wish to compare basins you might need to take this depth/permeability factor into account, it is a paramount factor superseding rank, moisture or even gas content (for the flow rate).

Interestingly, the Hartshorne coals are described as "friable because sheared and with thightly spaced cleating". This suggests that shearing doesn't always destroy permability.


I do not know where from you got this info about the pump size and casing. Sorry, but I just can't believe it.

1) It would be so really damned stupid that a beginner with Popular Mechanics wouldn't do it.

2) It's nearly impossible, for mechanical reasons, to initiate a lateral from a 5" cased main bore and that's why you will not find on the market any 5" whiptstock.

The main bore must therefore have been cased 7" or 7 5/8" and the troubles will have another reason. Reason ranging from the most benign (dirt on low side) to the worst (collapsed casing)...

Cheers
Z.