Ann: Drilling Update, page-32

When u drill, especially slowly as has been done apparently, lots of mud,water, drilling fluid - gets in there (ie contanimation) and can hide true results. Therefore it goes to the lab where it is looked under the microscope. Bit like washing greasy dishes in the sink....the pot(being core in drilling, hydrocarbons washed off) like grease on a pot...
Good reservoirs can be characterised by showing heavy gases when drilling and little or none on cores at surface...

So to the lab we go.

Hope that all makes sense