Surface geochemistry is a methodology that can be applied to a number of exploration situations.  However, a number of companies or individuals seem to apply it to every situation.  Surchace Geochem in petroleum exploration does not seem to have any application to resource plays.  At least to date.    The nature of resource plays is such that they require a large number of wells to be drilled.   High grading using surface geochem methods in coal bed methane or shale gas plays tends to be contrary to the logic of these reservoirs.  There may be leakage along fault systems to the surface in select areas.  But where would these fault and fracture systems identified at the surface be at depth?  

Coal bed methane reservoirs rely on water maintaining adsorbed methane in the coal by pressure.  Until the pressure is lowered to almost zero, in many cases, the methane gas will not flow to the well bore.  Recently, in some plays 3D or 2D seismic has been used to identify fracture trends.  This has had minimal success due to economics of coal bed methane resources.  Basically, the lower the cost for this type of resource play the better.  To date there is no verifiable evidence surface geochem was successful in a coal bed methane play.

In shale gas there are similar issues.  This type of resource is large and broad.  3D seismic is becoming successful because of the ability to identify fracutre and fault trends.  Surface geochem cannot identify in the subsurface where the frac or fault systems will be intersected by the drill bit.  This is why 3D is now being used aggressively and successfully. 

The level of detail sampling that needs to occur at the surface to find the fault or fracture trace is significiant and generally makes this method non-economic.  Also several of these plays have biogenic gas.  If the gas has migrated from the subsurface its difficult to separate from biogenic gas generated by biological activity at the surface.

 Surface Geochem is best used elsewhere .  

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