The concept of the solid content of the drilling mud: The percentage of the solid substance in the drilling mud volume is called the solid content of the drilling mud, which is usually expressed by percentage.
There is no difference in solids in the drilling mud. However, according to the different effects of solids on the drilling mud performance and on the drilling mud, the solid phase in the drilling mud can be divided into two types:
(1) The useful solid phase refers to the solid needed to maintain the drilling mud, such as bentonite powders, chemical treatment agents, and weighting agents, etc.
(2) The useless solid phase refers to the solid other than the useful solid phase, such as drilling cuttings, inferior bentonites, and sand, etc. There are many useless solids in the drilling mud. In order to effectively control the performance of the drilling mud, improve the downhole conditions and increase the drilling speed, all useless solid phases should be removed and the useful solids are controlled.
It has proved that the increase of the solid content in the drilling mud is an important reason for the decrease of the drilling rate. The high solid content of the drilling mud will seriously affect the performance of the drilling mud and bring many hazards to drilling. For example, the drill footage is reduced and the drilling equipment is seriously worn. The density and viscosity of the drilling mud increase, and the filter cake is thicker, which is prone to accidents such as lost circulation and stuck drilling, which damage the oil and gas reservoirs. It also increases the flow resistance and the pump pressure of the drilling mud, which is not conducive to jet drilling, causes frequent fluctuations in the performance of the drilling mud, and consumes a lot of drilling mud treatment agents. Therefore, to effectively increase the drilling speed and do safe drilling, it must strictly control the solid content and use non-dispersible low-solid drilling mud.