What is Fracking?
Fracking is the short form derived from the term hydraulic
fracturing. The term fracking refers to how the rock is fractured apart by the high
pressure mixture. This is a type of drilling that has been used commercially for 65 years. Thanks to major technological
advances hydraulic fracturing and horizontal drilling , is responsible
for swelling U.S. oil and natural gas production. Since the US began intensively using it since 2010, the
oil produced has increased from 5mb/d to 9mb/d. The process is being considered in
the UK and is mostly at its exploration stages having faced much opposition
from environmental pressure groups.
How does it work?
Once a shale rock
is identified, hydraulic fracturing is combined with horizontal drilling to tap
oil from shale and other tight rock formations. This is done by drilling a mile
or more below the surface before gradually turning horizontal and continuing
several thousand feet more. There therefore can be multiple wells accommodated on
a single surface site.
After drilling,
the well is cased and cemented and thereafter perforations are made on the
horizontal part of the well pipe. A mixture of water, sand and additives (in a
ratio of 90%:9.5%:0.5% respectively) is then pumped at high pressures to create
micro fractures within the rock. The
additives perform the following tasks.
-
Reduce friction (hence reduced pump pressure)
-
Prevent corrosion of the pipe (hence improved well
efficiency).
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