Page 35 - Introduction to Petroleum Engineering

PETROLEUM AND THE ENVIRONMENT 19
Evidence that human activity is causing climate to change more than it would
naturally change has motivated international attempts by proponents of anthropo-
genic climate change to regulate greenhouse gas emissions and transition as quickly
as possible from fossil fuels to energy sources such as wind and solar. Skeptics typi-
cally argue that reducing our dependence on fossil fuels is important, but they believe
that the transition should occur over a period of time that does not significantly harm
the global economy. One method for reducing the emission of CO into the atmosphere
2
is to collect and store carbon dioxide in geologic formations in a process known as
CO sequestration. Recent research has suggested that large‐scale sequestration of
2
greenhouse gases could alter subsurface stress to cause fault slippage and seismic
activity at the surface.

1.5.2 Environmental Issues
Fossil fuel producers should be good stewards of the Earth. From a personal perspec-
tive, they share the environment with everyone else. From a business perspective,
failure to protect the environment can lead to lawsuits, fines, and additional regula-
tion. There are many examples of society imposing penalties on operators for
behavior that could harm the environment or already harmed the environment. A few
examples are discussed here.
Shell UK reached an agreement with the British government in 1995 to dispose an
oil storage platform called the Brent Spar in the deep waters of the Atlantic. The envi-
ronmental protection group Greenpeace and its allies were concerned that oil left in
the platform would leak into the Atlantic. Greenpeace challenged the Shell UK plan
by occupying the platform and supporting demonstrations that, in some cases,
became violent. Shell UK abandoned the plan to sink the Brent Spar in the Atlantic
and instead used the structure as a ferry quay. As a consequence of this incident,
governments throughout Europe changed their rules regulating disposal of offshore
facilities (Wilkinson, 1997; Offshore Staff, 1998).
Another example is shale oil and gas development in populated areas. Shale oil
and gas development requires implementation of a technique known as hydraulic
fracturing. The only way to obtain economic flow rates of oil and gas from shale is
to fracture the rock. The fractures provide flow paths from the shale to the well.
Hydraulic fracturing requires the injection of large volumes of water at pressures that
are large enough to break the shale. The injected water carries chemicals and small
solid objects called proppants that are used to prop open fractures when the fracturing
process is completed, and the well is converted from an injection well operating at
high pressure to a production well operating at much lower pressure.
Some environmental issues associated with hydraulic fracturing include meeting
the demand for water to conduct hydraulic fracture treatments and disposing
produced water containing pollutants. One solution is to recycle the water. Another
solution is to inject the produced water in disposal wells. Both the fracture process
and the water disposal process can result in vibrations in the Earth that can be mea-
sured as seismic events. The fracture process takes place near the depth of the shale