Unconventionally produced gas (coalbed methane, shale gas, tight gas etc) will become increasingly important in the world’s energy mix. The success of the shale gas plays in North America only reinforces just how economically important these deposits are both on continental as well as global scales.
But, despite its success, there are large unknowns surrounding how the gas is stored within the shale gas system and how it gets out. Like coalbed methane, shale gas is both a source and a reservoir (a ‘continuous’ reservoir) and thus some things are comparable between the two different play types.
In a talk at the 2nd Annual Unconventional Gas (UGAS) Conference in Jakarta Indonesia Tim Moore and his co-author Leslie (‘Jingle’) Ruppert [US Geological Survey] presented a paper that compared these two types of unconventional gas reservoirs. The talk can be accessed here: Moore_Ruppert UGAS Jkt 13.pptx
Although there are some processes, for example gas sorption onto organic material, which are common to both play types, there are significant differences. So much so that, as others in the field have also pointed out, we don’t as yet have a tool box to measure – and thus model and predict – the mechanisms of gas generation and extraction in shale gas.
The current production is exciting, its profitable and is certainly a ‘game changer’; but in order for these successes to be repeated elsewhere, more understanding will be essential.