  The enormous pressure lifting the column of oil in a leaking oil well can
thwart efforts to seal the top of the well and prevent oil from rising. When
the oil cannot be stopped completely, we propose to slow its flow by filling
the well with a porous medium. That medium consists of countless small, dense,
streamlined objects that are dropped into the well and descend through the
rising oil at terminal velocity. The resulting heap of objects couples to the
oil via viscous and drag forces, dissipating the oil's energy and upward
momentum and significantly reducing its rate of flow.
