The rig circulatory system circulates drilling mud through the drill string and up the wellbore to carry cuttings to the surface and cool and lubricate the drill bit. Key components include mud pumps, shale shakers to remove cuttings from the mud, desanders and desilters to remove larger and finer particles, and degassers to remove gases from the mud before recycling it down the well. Different types of mud like water-based and oil-based are used depending on the formation being drilled.

1. Rig Circulatory System
By Irfan Ullah
Drilling Engineer, Trainee

2. Major Systems of Rig
Power System
Hoisting System
Rotary System
Circulating System
Well Control System

3. Need Of Circulation System
Maintain well integrity, balance the formation pressure
Removal of cutting from bottom hole to surface
Cooling and lubrication of tool bit
Circulation System

4. Types of Mud
I. Water-based mud
II. Oil-based mud
III. Foam
IV. air
OBM
Bear High Temp
𝐻2𝑆, salts and 𝐶𝑂2 are not soluble in it
Used for drilling through shales, that contains large clay

5. Mud
Pumps
Chock
Manifold
Shale
Shaker
Desander
Desilter
Degasser
Reserved
pit Tank
Active Tank
Mixing Tank
Rig Floor
Waste
pit
Poor
Boy
AP
RAMS
TB
TDS
Bit
Annulus
Cement

6. Components Involved
Mud Pumps
PD, Single or double acting
May pre-charge pumps is used

7. Chock Manifold
Assembly of pipes and valves to
control flow and pressure of mud
Stands
Joints of 2 or 3 drill pipes,
connected and stood vertically

8. Rotary hose
3 to 5 in in diameter
High Pressure flexible line
Used to connect standpipe and swivel
Swivel
A device that joins two parts, so that one or two can pivot freely
Conducts fluid between relatively rotatable components

9. Drill Pipes
Hollow, thin walled steel or aluminum alloy
Connect swivel to drill bit
Typically 27 to 32 feet in length
Drill bit
Tri-cone
I. Milled teeth, for soft rock
II. Insert teeth, for hard rock
 Fixed cutter, with diamond bit to cut
hard rock

10. Annulus
• The space around a pipe in a well bore,
the outer wall of which may be
the wall of either the bore hole or the
casing; sometimes termed the
annular space.
Bell Nipple
Pipe of large diameter, right above BOP
Allow drilling fluid to flow back over shale
shaker to mud tanks

11. Mud gas separator/ poor boy
In case of kick it allows mud and gas to flow
over baffle plates
Capture large volume of gas within the drilling
fluid
Possum belly
Metal container at head of shaker to receive
flow of mud

12. Shale shaker
Initial part of solid control equipment
Consist of vibrating screen
Remove large solid/ cutting from mud
Mud logger can examine formation here
Desander
 A centrifugal device for removing sand from
drilling fluid to prevent abrasion of the
pumps.
 It may be operated mechanically or by a
fast-moving stream of fluid inside a special
cone-shaped vessel, in which case it is
sometimes called a hydro cyclone.
Particle ranges from 45-75 micron-meter

13. Desilter
A centrifugal device, similar to a
desander, used to remove very fine
particles, or silt, from drilling fluid
Remove silt of range 15-44
micron meter
Degasser
Separate gases to avoid bubbles
formation
Subject Mud to vacuum, so that
gases expands and extracted from
mud

14. Reservoir Tanks
Used for back up of mud
Mixing Tank
Mixing of mud, additives and chemicals to acquire the desired properties of
mud (density, viscosity etc.)
Active tanks
Tanks where suction to the pumps is provided

15. Bulk Mud Component Storage
• Hopper type tanks for storage of drilling fluid components