ACIDIZING
FRACTURING
Fracturing process is done by high
pressure pumps so has to develop
enough fluid pressure
at the bottom
of a well which
will actually crack (break) the
formation . This makes
it possible to
introduce proppant materials
such as sand
, walnut hulls , or
other small particles
of materials into
the newly created
crevices to keep
the fractures propped
open when the
pressure is relieved
. This process increases
the flow of
reservoir fluid into
the well bore .
HYDRAULIC
FRACTURING
A
fracture is
a a break
in the continuity
or loss of
cohesion across the
surface of failure
.The naturally occuring
fractures in the
rock such ad
cracks ,fissures ,joints ,faults
etc .are caused due
to thermal ,chemical
and other Geo – stress imbalances
in the past
.The hydraulic fracture
is a process
of creating a
fracture in a
porous medium by
injecting fluid pressure
through a well
bore in order
to overcome stresses in the strata and to cause material
failure of the
porous medium .
The hydraulic
fracturing is desirable
when the formation
is very tight
, having low permeability and
poor conductivity and
is at relatively
higher pressure . The
parting of rock
is effected by
pumping of hydraulic
power fluid in
the well bore
at a pressure
exceeding the fracture
pressure (pbh ) based
on fracture gradient
. The created fractures
are preserved from
collapsing and closing
by putting propping
agent .
CHEMICAL TREATMENT
Chemical treatment
are those in
which acid is
not a significant
part . Although many
of the materials
in this group
are often used
in conjuction with
fracturing and acidizing
, they have definite
application in their
own right .
Due to the
surface tension , water
can sometimes cause a
blockage when present in
the tiny pore
spaces of a
formation . Surface tension of
water can be lowered by certain chemicals. Thesechemicals break
large drops of
water , thus allowing fluid,
previously trapped by
surface tension , to
be released to
flow to the
wellbore .
In many
instances , when oil
and water become
mixed to form an emulsion .When continuously agitated,the emulsion
becomes a thick viscous fluid which
reduces the flow of
liquid in to the
well bore .Chemicals
are used to break
this emulsion .Thus increasing the fluid flow in to the
well by decreasing the viscosity.
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