Ann: Zapato-1 Drilling Update, page-514

And in my view it isn't a big deal - As NedKelky said in the Zapato thread - Oil over the shakers refers to an extreme version of “oil shows”. It is an informal jargon and ranges from meaning there was enough oil in the rock being drilled that it has been detectable visually in the mud coming back over the shale shakers (that separate rock cuttings from the mud) through to fluorescence being seen under black light on the cuttings through a microscope and occasionally, hydrocarbons detected by the gas chromatograph. Normally it is just slang for a really strong oil show.Normally it is a good thing in terms of the prospectivity of the well. When there's oil flowing it's exciting - we know it's down there but it's only worth anything once put in a tank.

MIght be a duster is just BS - people getting excited for excitement sake.