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Note: Anticlines and other potential hydrocarbon traps can be located using
seismic and other techniques, but the only way to find out if petroleum is present
is to drill a well. Here we have two identical geologic structures side by side
and only one of them contains oil. Only about one in ten wildcat wells is a
discovery.
Figure 4.1 – Luck Does Play a Role!

Drilling a well involves a whole new cast of characters.
The drilling engineer, the driller, the tool pusher, the roustabouts,
the roughnecks, the logging crew and many others. We will not get
into detail regarding the responsibilities of each of these
individuals, as this reaches beyond the scope of this manual, but
we will provide a general description of the drilling process and its
challenges.
The overall objective of drilling is to bore a hole (the well
bore) into the ground until you penetrate a target rock formation
that has been identified by the geologists and geophysicists as
having the potential to contain commercial hydrocarbons. We
know from Chapter 3 that the formations through which we will be
drilling may be porous and permeable, and may contain fluids (oil,
water or natural gas) at very high pressures.
If we were to drill into such a formation without taking the
appropriate precautions, the fluids would spew violently out of the
hole and we'd have what's called a blowout. Blowouts can be
extremely dange rous as well as damaging to the environment. In
the early days of the oil industry, before drilling technology had
evolved significantly, when a well struck oil it often blew out.
These blowouts frequently caught fire, destroyed the rig, and
sometimes cost rig workers their lives.

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