How a Well is Drilled on Land

How a Well is Drilled on Land

1

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.


2

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..


3

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.


4

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. .


5

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.


6

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.


7

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.


8

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.


9


Head Wear Bushing

A wear bushing is installed to

protect the interior of the

casing head from damage

by drilling equipment.


10

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. .


11


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.


12

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.


13

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.


14

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.


15


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..


16

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.


17

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.


18

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. .


19

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.

How a Well is Drilled on Land

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