Abstract: A method of drilling a formation, comprising drilling at least one wellbore in a coal bed methane formation using a drill string having an inner string and an outer string, the inner string and outer string defining a passageway therebetween; providing a drilling medium to drill apparatus for use in drilling the formation, the drilling medium provided through one of the inner or outer strings; and returning a combined medium comprising drilling medium, drilling cuttings, produced water and/or gas from the formation to surface via the other of the inner and outer string. Subsequent to drilling the formation, there are also described methods and apparatus for producing from coal bed methane formations. In some examples, this includes producing a first fluid, or fluid product from a first flow passage within a wellbore; and also producing a second fluid, or fluid product, from a second flow passage within the wellbore.

Abstract: A system and method for drilling a formation and a method for computing expected production from a wellbore in a formation and/or hydrocarbon reserves associated with the formation, the formation having a plurality of naturally-occurring fractures, the method including computationally modelling the formation; computing one or more wellbore positions intersecting some or all of the fractures; and computing an expected production from the wellbore at least partially based on an expected wellbore damage associated with a particular type of drilling technique.