worth having a look at., page-109

Csg wells flow at VERY very low rates due to the iimpermable nature of the coal seam cormation. pretty much its the tightest form of gas you can get and it requires
hundreds and sometimes thousands of wells to make a project worthwhile. You would need a fleet of rigs or else you will be there for decades using one rig.

The cost of drilling a well is more expensive and complicated compared to a conventional well, not to mention the processing facilities required.