Drilling mud or drilling fluid is one of the most important requirements for drilling deep wells in various industries. In the oil, gas, water and other minerals exploration, the drilling of deep wells and access to the subsoil, the presence of drilling fluids is a necessity. Depending on the purpose of drilling and the type of soil in the area, various methods are considered for drilling; but the common denominator of all these methods is the use of drilling mud or drilling fluid.
The use of this fluid has different purposes and in different excavations, different fluids with different properties are used. In this article, we will introduce the use of drilling fluid and the role of different materials in it.
Applications of drilling fluids
The first and the most important application of drilling mud is to remove drilling-based chips from deep wells. This helps to make deep well drilling faster and easier.
But the application of this product is not limited to removing chips. As the chips exit, the presence of this fluid cools down the drill bit and makes it run smoother.
Another important application of drilling fluids is to prevent wells from falling. Deep wells are very prone to collapse. The walls of these wells usually tend to collapse permanently under the pressure of drilling and physical imbalance. Meanwhile, the presence of drilling fluids in the well prevents the collapse of the wall.
First of all, drilling mud reduces the possibility of falling by putting pressure on the wall. Secondly, drilling fluids by penetrating the empty parts of the wall and filling the pores, etc., increase the strength of the well wall and reduce the possibility of its falling.
Of course, it should be noted that this feature causes drilling fluid wastage through the well wall; Adding different materials to the fluid and changing its properties, in addition to increasing the properties of drilling fluid to prevent the well from falling, can also reduce its waste.
Working process of drilling mud
One of the most important characteristics of drilling mud is its weight. Specialists in manufacturing drilling fluids, by changing its weight, try to increase its efficiency. When the weight of the mud rises; larger and heavier chips can float in it. So it can move them out of the well with more power.
In contrast, by increasing the mud weight, its fluidity and speed of movement decreases and it will have less capabilities in lubricating the drill and cooling it.
Given the above, drilling fluid manufacturers are always looking for the tipping point to get the most out of drilling fluids.
Also, in practice, the working process of drilling fluids in simple language is such that the desired fluid enters the well, floats the chips in it and takes them out of the well with it. After this stage, the fluid is filtered by various filters and by taking the chips from it, it returns to the well.
This flow continues from the inside of the rotating bowl to the drill string, the head, the empty space between the drill string and the well, and finally the tank filter.
Types of additives to drilling fluids
Each material adds certain properties to the drilling mud to change its specific weight, density, and chemical properties.
The most common mineral additives to drilling fluid include bentonite, mica, graphite, barite, galena, lime, gypsum, asbestos, salt, sodium carbonate and bicarbonate, perlite, and volcanic ash. Drilling fluid base can also be water, oil and a combination of air and foam. Drilling mud base is the main ingredient to which minerals are added.