1.1 Shale Shaker
Shale shakers are components of drilling equipment used in many industries, such as coal cleaning, mining, oil and gas drilling.
They are considered to be the first phase of a solids control system on a drilling rig, they are used to
remove large solids also called cuttings from the drilling fluid, more commonly called “Mud” due to its similar appearance.
Drilling fluids are integral to the drilling process and, among other functions, serve to lubricate and cool the drill bit as well as
convey the drilled cuttings away from the bore hole. These fluids are a mixture of various chemicals in a water or oil based solution
and can be very expensive to make. For both environmental reasons and to reduce the cost of drilling operations, drilling fluid losses
are minimized by stripping them away from the drilled cuttings before the cuttings are disposed of.
This is done using a multitude of specialized machines and tanks.
Shale shakers are the primary solids separation tool on a rig. After returning to the surface of the well the used drilling fluid flows
directly to the shale shakers where it begins to be processed. Once processed by the shale shakers the drilling fluid is deposited into
the mud tanks where other solid control equipment begin to remove the finer solids from it. The solids removed by the shale shaker are
discharged out of the discharge port into a separate holding tank where they await further treatment or disposal.
Shale shakers are considered by most of the drilling industry to be the most important device in the solid control system as the performance
of the successive equipment directly relates to the cleanliness of the treated drilling fluid.
1.2 Vacuum Degasser
degasser is a device used in drilling to remove gasses from drilling fluid which could otherwise form bubbles.
For small amount of entrained gas in a drilling fluid, the degasser can play a major role of removing small bubbles that a liquid film has
enveloped and entrapped.In order for it to be released and break out the air and gas such as methane, H2S and CO2 from the mud to the surface,
the drilling fluid must pass degassing technique and it can be accomplished by the equipment called degasser which is also a major part of a mud systems.
Vacuum Type is the most common form of degasser. It can be horizontal, vertical or round vessel. A vacuum action is created to pull in the gas cut mud.
When the liquid enters the tank it will flow and be distributed to a layer of internal baffle plates designed for the mud to flow in thin laminar film
and is exposed to a vacuum that forces the gas to escape and break out of the mud.The vacuum pump moves the escaping gas from the vessel discharging
it to the rig’s flare or environmental control system.
1.3 Mud Cleaner
mud cleaner is a combination of desanders and/or desilters to remove drilled solids from mud.
A mud cleaner is a combination of desanders and/or desilters mounted over a shaker with a fine mesh screen. A mud is fed to the inlet of the hydrocyclone
(desander and/or desilter) to separate particles and the underflow passes to the fine screen mesh where in particles larger than barite are discarded and thrown away.
In most drilling operations, a mud cleaner is installed in its mud systems. It is usually located in a mud tank in the same location as with the desilters.
The weighted mud flows to the inlet head section of the desander and/or desilter entering the hydrocyclones for separation of particles.
Mud leaving the underflow is further screened with fine mesh to separate larger particles allowing only barite size particles to pass through the screen returning
and recovering then the clean mud.
The purpose of the mud cleaner is to remove drilled solids larger than barite. Solids larger than 74-105 micrometres can be removed by the mud cleaner before the
viscosity builds up. Mud cleaner can effectively control weighted drilling fluid solid content. Prevent differential pressure sticking, adhesion stuck drill accident,
reduce the drill string and the filter cake thichness on bond issues
Desanders and desilters are solid control equipment with a set of hydrocyclones that separate sand and silt from the drilling fluids in drilling rigs.
Desanders are installed on top of the mud tank following the shale shaker and the degasser, but before the desilter. Desander removes the abrasive solids from
the drilling fluids which cannot be removed by shakers.
Normally the solids diameter for desander to be separated would be 45~74μm, and 15~44μm for desilter
A hydrocyclone much like a desander except that its design incorporates a greater number of smaller cones.
As with the desander, its purpose is to remove unwanted solids from the mud system. The smaller cones allow the desilter to efficiently remove smaller diameter drill solids
than a desander does. For that reason, the desilter is located downstream from the desander in the surface mud system.
1.6. Decant Contrifuge
Decanting Centrifuge separate the suspending fluids using the principle of centrifugal action, the suspending fluids is pushed into the rotor drum through the inlet pipe
and the fluid hole of the spiral feeder. Under the influence of centrifugal force, solid phase particles are pushed to the internal wall of the drum, then to the nud export of
the small end of the drum and excreted. But the fluids is excreted from the overflow hole of the large end.
Such cycle is in order to achieve the purpose of continuous separation.High speed decanting centrifuge are effective for separation
1.7. Mud Gas Seperator
Mud Gas Separator is commonly called a gas-buster or poor boy degasser. It captures and separates large volume of free gas within the drilling fluid.
If there is a “KICK” situation, this vessel separates the mud and the gas by allowing it to flow over baffle plates. The gas then is forced to flow through a line and vent it to a flare.
A “KICK” situation happens when the annular hydrostatic pressure in a drilling well temporarily (and usually relatively suddenly) falls below that of the formation, or pore, pressure
in a permeable section downhole, and before control of the situation is lost.