Download - How a Well is Drilled on Land
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How a Well is Drilled on Land
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Step 1: Digging a Cellar
On land, a majority of wells
begin with digging a cellar
from three to fifteen feet in
depth. The purpose of a
cellar is to align the
production Christmas tree at
ground level, providing easier
access to the valves,
chokes, and other equipment.
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How a Well is Drilled on Land
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Step 2: Running a Conductor
Pipe
The first string of pipe used
in a well is called the
conductor pipe, or drive pipe.
The pipe is usually 30-36
inches in diameter. A large
diameter hole is drilled to
a specified depth, usually
one or two hundred feet, and
the pipe is driven into the
ground..
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How a Well is Drilled on Land
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Step 3: Connecting the BOP
An adapter flange, or drilling
flange, is welded to the
conductor pipe to connect a
diverter system or a blowout
preventer system to control
wellhead pressure.
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How a Well is Drilled on Land
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Step 4: Running the Surface
Pipe
A hole is drilled for the wells
first string of pipe, the
surface pipe, and the pipe is
run in the hole. There may be
several strings of pipe in a
well, each run to a different
depth. The number of strings
is determined by the number
of zones being drilled
through. These can include
fresh water, salt water, and
potential production zones.
Each zone is isolated, or
cased off, until it is to be
produced. .
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How a Well is Drilled on Land
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Step 5: Connecting the
Surface Pipe
The surface pipe is
cemented in place back to
the surface. This holds the
pipe in place and seals off
the zone. A cement plug is
left in the pipe so that the
BOP system may be
disconnected safely. The
BOP is then removed from
the adapter flange.
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How a Well is Drilled on Land
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Step 6: Cutting the Conductor
Pipe and Surface Casing
The surface pipe is drained,
the adapter flange (or drilling
flange) is cut off, and both the
conductor pipe and the
surface casing are cut to the
proper height to allow the top
of the completed wellhead
to be at ground level.
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How a Well is Drilled on Land
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Step 7: Installing the Casing
Head Housing and Base
Plate
The casing head housing is
welded in place on the
inside diameter and the
outside diameter of the
surface casing. The
housing is then tested to
assure there are no leak
paths in the welds.
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How a Well is Drilled on Land
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Step 8: Installing the BOP
System
The BOP system is installed
above the casing head
housing and then tested. To
test the BOP system, the test
plug is made up on the drill
string and lowered through
the BOP system onto the
casing head bowl. Pressure
is applied from above the
plug to test the BOP system.
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How a Well is Drilled on Land
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Step 9: Installing the Casing
Head Wear Bushing
A wear bushing is installed to
protect the interior of the
casing head from damage
by drilling equipment.
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How a Well is Drilled on Land
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Step 10: Installing the
Intermediate String
A hole is drilled for the
intermediate string and the
casing is run in the hole
and cemented in place. A
cement plug is left in the
intermediate casing, just as it
was in the surface casing. .
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How a Well is Drilled on Land
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Step 11: Installing the Casing
Hanger and Casing Spool
The intermediate casing is
suspended from the block
above the rig floor, the BOP
is picked up, and the casing
hanger is installed on top of
the casing head. Holes are
cut in the casing to allow the
drilling fluids to drain out of
the casing riser. When the
fluid has drained, the casing
is cut off to the appropriate
height and the casing spool
is installed.
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How a Well is Drilled on Land
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Step 12: Installing the BOP
System
The BOP system is installed
above the casing spool and
then tested. To test the BOP
system, the test plug is made
up on the drill string and
lowered through the BOP
system onto the casing head
bowl. Pressure is applied
from above the plug to test
the BOP system.
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How a Well is Drilled on Land
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Step 13: Installing the Wear
Bushing
The wear bushing running
tool is made up on the drill
string and the wear bushing
installed on the running tool.
The wear bushing is then
lowered through the BOP
system, until it rests in the
casing spool bowl, then is
locked into place. The
running tool is removed and
drilling resumes.
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How a Well is Drilled on Land
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Step 14: Running the
Production Casing String
The production casing string
is usually run to the total
depth of the well. A hole is
drilled for the production
casing and the casing is run
in the hole and cemented
into place. A cement plug is
left in the production casing,
as in the previous steps.
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How a Well is Drilled on Land
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Step 15: Installing the Casing
Hanger and Tubing Spool
The production casing is
suspended from the
elevators at the rig floor, the
BOP is picked up, and the
production casing hanger is
installed in the same way as
the previous casing hanger.
The tubing spool is installed
in the same way as the
casing spool. After the spool
has been installed, the seals
and connections are tested,
and the BOP system is
reinstalled..
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How a Well is Drilled on Land
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Step 16: Running the
Production Tubing
The production tubing is
installed inside the
production casing. Unlike
casing, the production tubing
is not cemented in the well
so it may be removed later, if
necessary.
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How a Well is Drilled on Land
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Step 17: Installing the Down
hole Packer Assembly
A down hole packer
assembly (a type of seal
assembly) is run and
installed in the
production casing to seal the
reservoir from all strings of
pipe, except the production
tubing.
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How a Well is Drilled on Land
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Step 18: Installing the Tubing
Hanger
The tubing hanger is installed
on the tubing at the rig floor,
then lowered into
the bowl of the tubing spool.
The packer seals are tested,
and a backpressure valve is
installed in the tubing hanger
so that the BOP can be
removed safely. After the
valve has been installed the
BOP is removed. .
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How a Well is Drilled on Land
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Step 19: Installing the Christmas Tree
The production Christmas tree, sometimes
called the flow assembly, controls the flow
of the well. It is made up of a seal flange, or
tubing head adapter, a series of valves, and a
choke. The valves are stacked vertically and
horizontally to provide backup should a
valve fail. Each Christmas tree has at least
one actuated surface safety valve to shut
down the well in an emergency and prevent
damage to equipment downstream. The
Christmas tree is connected to a flowline,
which transports the wells fluid or gas.
The Christmas tree is oriented properly,
picked up, lowered over the neck of the
tubing hanger, and connected to the tubing
spool. The connections and seals are tested,
and the well is now ready for production
testing.