Circulation System in Drilling Rigs:

Circulation system uh is used for

circulating our mud.

but why do we need mud uh why do we need

mud at first place okay

see let's see that these are the few

functions mentioned

of the drilling mud we use the first one

is very important that is the over to

muddy is used to over balance the

formation pressure

now what actually happens is as we are

going deep inside the earth

our pressure is increasing because with

depth pressure

pressure also increases its simple

where p is directly proportional to our

h in this case is our depth of the

valve

okay so as we are going deep inside the

earth

our pressure is increasing so when we

when we drill these highly pressurized

rocks what happens is that oil and gas

will try to

come up the surface obviously because

any fluid travels from high pressure to

low pressure

now in this case high pressure is at the

bottom of a drill board

and the our lesser pressure is at the

surface

so our oil and gas will come up will try

to come up to the surface

with a huge amount with a huge pressure

so it can be

it can cause a lot of destruction which

we use drilling mud now how drilling mud

counterbalance this pressure and uh

doesn't allow oil and gas to come up

because the drilling might at the depth

of

at some some depth there will be a

hydro-static pressure of drilling mod as

well

that is again rho gh but density of

rho is density of mud density of fluid

and

h is again the depth of the velvet in at

which our

bit is present okay now second function

is

to cool and lubricate the mud sorry to

cool and lubricate the drilling bit

see a drilling bit is doing our main

function to drill the holes and rotating

continuously okay

so we need to cool down that machinery

in order to

prevent damage to drill bit now uh

there's a

there's a very old story uh

in us in 1900s uh some people

used what they did was uh they watered a

field and they ran and they ran a group

of animals from this field

as a result a lot of mud was produced

and they used this mud

to cool the drill bit so this is where

our

drilling fluid which is also known as

drilling mud

uh gets the name okay now the third part

is

third function is these drilling mud

are used to carry the cuttings up to the

surface now what are the cuttings

cuttings are nothing but the small

pieces of rock which are being drilled

see as we are drilling our drilling bit

is drilling our rock is cutting into

our rock is getting cut into the pieces

right so these pieces of ropes are

coming up to the surface

with the help of with the help of

drilling fluid how this ah i'll explain

in a bit that how this

cuttings are coming up to the surface

you can see here

this this image what is happening here

is

that drilling mud is coming from the

drill pipe

drill pipe this is a drill pipe hollow

drill pipe

mud is coming now in this is a drill bit

in drill bit there are small small

nozzles like

drill drill mud is coming from drill

pipe to drill bits and through these

nozzles

mud is again getting in the annuls this

is known as annuls

annuls is nothing but a space space

between the

bore hole and the drill pipe so through

these envelopes our drill cuttings are

going to the surface

okay now the

another main function is that the

drilling mode maintains the well

integrity

now what exactly is well integrity see

uh

suppose see this this figure okay this

this is a hollow pipe shown here right

hollow pipe nothing is inside the pipe

and we are applying a lot of pressure

we are applying we are applying

a lot of pressure here in the sides of

the slide what will happen is

that due to excess pressure this hollow

pipe will

collapse this is the collapsed pipe so

similarly if drill mud is not present

inside our

drill drill so if

if if our mud is not present inside our

drill hole drilled hole

and there is a lot of excessive pressure

coming coming from

the sides to the elbow it will

eventually collapse

so drill mud also prevents this

collapsing now

okay now let's see how the mud travels

what is the journey of

mud from where it comes and where it

goes

okay okay let me explain to you by this

figure over

this is this is the diagram

of a circulation system in our eggs

now mud actually star mud is pumped from

a

mud pump which is shown here this is a

mud pump

now this mud pump is pushing or pushing

our mud through surface lines

to the stand pipe here it is a stand

pipe

here it's a sand stand pipe now from

stand pipe it goes to rotary hose and

rotary hose to swivel

now main function of rotary hoses here

is that it connects the

stand pipe to this fuel so that our

highly pressurized

mud can come to the cali now through

this swivel

mud is going to kali and from kali it is

going to

sorry it is going to the drill pipe and

drill bits

now see this one this is mud coming

coming down there and going to the

envelopes going from envelopes here

now how when it reaches the surface it

crosses the bop and above bop

there is a this one there is a

hollow long casing pipe known as a so

not casing pipe

a piece of pipe known as a bell nipple

this pale nipple the main function of

this bell nipple

is to connect the flow line

this is a flow line now what flan does

is

that it takes the mud from envelopes

it goes to the bell nipple and from bell

nipple it goes to the flow line

and then it travels to the shale shaker

descender

d filter okay

now what the shale shaker descender d

center are

they are nothing but they are used for

conditioning of mud what do i mean by

conditioning is that they clean the mud

okay the shale shaker are nothing but

the vibrating screens

which actually uh filter filters the

rocky part that is cuttings and separate

it from the mud

it ah it take the uh shale part shell

means rock parts

and it transmits mud again to the

descender

descender again filters the sand now

from descender it goes to de-filter it

ed-filter filters the silt

now basically there's a difference

between shale shaker designer and these

shelter is that

the size of material they are filtering

like shale shaker is filtering a bigger

material

d sander is filtering the sand which is

a smaller

smaller smaller particles than the shale

or rocks material which was filtered by

shell shaker

this filter is separating the tiniest of

particles present in the mud then from

these filter it is going to degassed

which is actually eliminating the gas

any amount of gas

present in the mud and this decay then

connects to mud tanks

used to store the mud and then

these mud tanks these mud tanks are

again

transfers the mud to our mud pumps

and

the whole cycle continues again

so this is the basically a whole journey

of mud how mud travels

this comes from mud pumps and

travels all the way to the drill pipe

and again comes to the

again comes to the mud pumps now

basically there are two types of mud

pumps which which are being used in

industry uh duplex pump and the triple x

pump.