The performance of a shale shaker is majorly influenced by a lot of factors and variables. One of the most important factors affecting the performance of a shale shaker is the theological properties of the drilling fluid, the concentration of the solid, size distribution, frequency of vibration, acceleration, the pattern of vibration, mesh and screen area, and the angle of the deck. However, drilling fluid plays a sophisticated role when it comes to influencing the performance of the shale shaker. In this article, we will discuss these factors briefly; read on to know more.
Generally, the capacity of the shale shaker is maximized when the number of separated cuttings removed from the screen is balanced with the amount of filtrated drilling mud that is passed through the screen.
Tilting the screen up helps in saving fluid and reduces the velocity of the solid. On the other hand, tilting the screen down will increase the mudflow and cut the moisture at the exit. However, the optimal angle of each shaker differs depending on the manufacturer. In addition, if the screen is tilted further, then it will cause the particles to accumulate on the screen and clogs the screen pores. Nevertheless, the underlying influence of the vibration on the displacement of the fluid in different media is still not understood.
It is assumed that the alteration in the pore structure and the rearrangement of the particle help in increasing the flow rate. The vibration of the fluid velocity influences the drilling of fluids as a non-wetting phase in different column-filled water and sand. In addition, increasing the amplitude of the vibration will enhance the flow rate of the drilling mud.
Another factor that influences the vibration on the flow rate is the phenomenon of capillary entrapment, also known as capillary dilation. The process of capillary dilation is quite promising, and the concept for this mechanism is developed on the basis of interfacial tension. This is believed to be the most crucial parameter in the diverse flow of porous media.
Due to the alteration of pore size, the fluid is trapped in different porous media. This causes a difference in the capillary pressure. If there is a slight imbalance of pressure, then the flow rate of liquid is altered through the porous medium. However, it is clear from the experiment that providing external vibration will enact an inertial body force to act on the fluid. This will eventually result in the backflow of trapped fluid pushed into the stream of flow by screen vibration. A result of vibration on the increase of flow rate tends to create an internal circulation in the mud and aids the additional fluid time to hit the screen.
The solid-liquid separation process is impacted by both the particle concentration and the particle size distribution. Especially in drilling mud, increasing the solid concentration compromises the performance of the drilling operation. According to some of the results of the experimental studies, muds compromising more than 10% by mass solids are responsible for possible failure associated with the filtering process. Furthermore, in micro-bit drilling findings, it was revealed that immensely small particles in a drilling mud create a greater negative impact on the flow rate– than bigger particles of the same size.
The size of the particle is a major factor in defining the sensitivity during the filtering process. It is often noticed that particles of size less than one micron cause more harm in the filtering process than particles of size bigger than one micron. However, almost all equipment used for solid-liquid separation in the drilling industry is known to remove particles bigger than 1 micron. The vibration of the shale shaker particularly alters the particle structure creation in the drilling mud. This eventually leads to a difference in the drilling result. It often happens due to the presence of vibration, which reduces the shear stress of the drilling fluid. Regardless of polymeric drilling fluid, which is not affected by the presence of vibration.
According to the results of a generic study based on the effect of plastic viscosity and the effective yield values that demonstrates the capacity of a shale shaker– the plastic viscosity of any drilling mud that flows through the screen and cake has a certain effect on the capacity. In contrast, the yield value has little to no effect on the performance of the shale shaker. It is also predicted that increasing the plastic viscosity and the yield value of drilling fluid will eventually increase the screen area required in a shaker to get the desired result. However, you can enhance the capacity of the shale shaker by increasing the screen area, acceleration, and shaker angle and decreasing the plastic viscosity.
Shale shakers are designed by keeping multiple factors in mind, and one of the essential parameters used in designing shale shakers is the installation or placement of the vibrating motors on the shale shaker. Some manufacturers are of the belief that if a vibrator is placed precisely on the shaker support, then it will eliminate the necessity of inclining the shaker downward to attain the desired mass rate of solids on the screen. However, it is essential to note that inclining the screen in the downward direction will decrease the flow rate of the drilling mud and will increase the moisture content of the particles, potentially leaving the channel of the shale shaker. Both of which are considered to be undesirable.
The fact that raising the frequency will increase the capacity while lowering the amplitude will decrease the capacity was proven by Porter’s experimental work on the vibrating electromagnetic screen. This finding helped in setting an ideal setup for operating circumstances. After reaching an optimum point, the flow rate eventually decreases. However, the most effective angle for the inclination was found to be 33 degrees.
Frequency is one of the most important factors when it comes to impacting screen performance. However, it is quite contradicting as some studies have found the exact opposite. Frequency alters according to the size of the feed.
For any feed with a particle size close to the opening, the relationship between the frequency and the particle size will reveal that frequency is one of the most advantageous parameters. However, other studies have found that the effectiveness of screening is decreased to a certain extent by increasing the frequency of screening.
Deck angle is another important factor when it comes to defining the effective mesh area. Increasing the deck angle results in an increased mesh area and the effective number of contacts per unit of the screen length. In addition, the deck angle also helps in increasing the flow of the particles. However, many researchers are of the opinion that an angle greater than 15° will possibly decrease the efficiency of the process.
Since the deck angle increases the usable mesh area and the measurable number of contacts per unit of the screen length when the deck angle is raised to a certain extent, this possibly has a certain effect on the g-force.
The deck angle is increased intentionally to ensure that the particles flow effortlessly. However, according to researchers, if the deck angle is increased more than 15°, then the method’s efficiency is decreased.
According to the shale shaker result, it operated at 4g of acceleration with two different frequencies of 20 Hz and 60 Hz. However, the frequency does not have any significant influence on the fluid capacity of the shale shaker. It was proven during the research that the flow rate is somewhat lower at 60 Hz frequency as compared to 20 Hz. The researchers have found that 100*100 mesh screens with three different drilling fluids were impacted greatly due to acceleration and the capacity of the shale shaker.
It was reported that screens with greater conductivity performed extremely well as compared to other similar screens. However, the hypnotized method used for the improvement is considerably based on the permeability of the screen and its thickness rather than just the proportion of the screen.
However, the capacity of the shale shaker is reported to grow when the g-force of the shaker is increased. The gravity considerably affected the development rate, and the capacity of the shale shaker tends to increase rapidly. At a certain level of g-force, the acceleration does not influence the effective functioning of the shale shaker after reaching a specific point.
Multiple factors influence the performance of the shale shaker, and most of them are of keen importance. These factors should be monitored for the smooth and effective running of the shale shaker. However, we hope you must have gathered insight into the factors that influence the performance of the shale shaker through this article.