Ann: Trading Halt, page-110

I don't know a lot about drilling but my take on this scenario is that they are coring the well because they have struck something of sufficient worth to undertake the coring process.
If they hadn't found something then they would have waited till they did to do the core sampling.
As I understand things the coring is essential to be able to get a handle on the grain size of the sandstone and therefore get an accurate assessment of the commerciality of the find through the calculation of permiability.
Maybe OldGeo, Alexii or trout maybe able to shed more light on the subject.