What is Shale Shaker?
Shale shakers are components of drilling equipment used in many industries, such as coal cleaning, mining, oil and gas drilling. They are the first phase of a solid controls system on a drilling rig, and are used to remove large solids (cuttings) from the drilling fluids (“mud”).
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 begins 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.
Shale Shaker Structure
The Hopper, commonly called the “base” serves as both a platform for the shaker and collection pan for the fluid processed by the shaker screens, also known as “underflow”.
The hopper can be ordered according to the needs of the drilling fluid, aka “mud” system.
It can come in different depths to accommodate larger quantities of drilling fluid as well as have different ports for returning the underflow to the mud system.
The Feeder is essentially a collection pan for the drilling fluid before it is processed by the shaker, it can come in many different shapes and sizes to accommodate the needs of the mud system. The most commonly used feeder is known as the weir feeder, the drilling fluid enters the feeder usually through a pipe welded to the outside wall near the bottom of the feeder tank, it fills the feeder to a predetermined point and like water flowing over a dam the mud (drilling fluid) spills over the weir and onto the screening area of the shaker. This method of feeding the shaker is most widely used due to its ability to evenly distribute the mud along the entire width of the shaker allowing for maximum use of the shaker’s screening deck area.
Also known as the screen “bed” it is the most important part of the machine, it is responsible for transferring the shaking intensity of the machine, measured in “G’s”, while keeping the “shaking” motion even throughout the entire basket. It must do all that while holding the screens securely in place, eliminating drilled solids bypass to the hopper and allowing for easy operation and maintenance of the machine. Different brands of shakers have different methods of fulfilling these demands by using specialized screen tensioning apparatus, rubber seals around the screens, basket reinforcement to limit flex, rubber Float Mounts rather than springs, rubber Deck seals and selective vibrator placement.
This is the device which applies the vibratory force and motion type to the shaker bed. A vibrator is a specialized motor built for the purpose of vibrating, while containing an electric motor to provide the rotary motion it uses a set of eccentric weights to provide an omnidirectional force.
To produce the proper Linear motion a second, counter rotating, vibrator is added in parallel to the first. This is what gives us the linear motion, “high G” shaking of the basket.
Basket Aligning Mechanism
The shaker basket must be capable of changing its angle to accommodate various flow rates of drilling fluids and to maximize the use of the shaker bed, this is where the angling mechanism plays an important part.