[DonnerT]

The mud is not abrasive. It is a lubricant, but at near 10,000 psi it will abrade slowly. The trick is to balance the gas/oil pressure with a column of heavy mud down the bore before the BOP and casings loose their integrity.

[mad_as_he$$]

Sorry but under that kind of pressure it has abrasive qualities. Even the very fine stuff is somewhat abrasive. Think of adding it to a pressure washer and washing your car.