oil shows at snatcher 2...., page-11

As correctly mentioned by others they will have stopped pretty much at the top sand. They will change to a core barrel and cut a core. The reason for this is to allow them to do various tests on the reservoir rock, for example to test it's permeability. Coring is not an alternative to a DST which tests the deliverability of the well.

Depending on shows at the base of the core they will probably drill ahead to allow for a logging pocket below the sand to allow wireline tools to be run. You would typically need about 30 m below base hydrocarbon.

I'm only a Driller so apologies for the over-simplification to any Geo's on this thread.