2) Horizontal drilling. For
horizontal drilling, the
well bore (the hole the well
makes under the ground)
is drilled vertically, then
turns to travel horizontally
through the target layer;
thus, horizontal drilling.
This allows each well to
come in contact with, and
therefore fracture, a larger
amount of the formation.
See Figure 1. This is especially useful in thin layers,
like the Marcellus Shale.
It requires far more water