In the process of drilling, when the drilling fluid returns to the wellhead with cuttings through the circulation system, flows into the shaker through the elevated trough, and then flows through the buffer trough and diverter plate to the screen surface of periodic vibration, the solid-liquid separation process begins. However, there is a process of solid-liquid separation, when the drilling fluid just flows to the screen, it is not possible to immediately separate, but at the same time, a small part of the screen, most of the liquid phase immediately dispersed along the screen surface, and the formation of a mud layer on the screen surface, the mud layer is thinner and thinner with the separation, and continues to a certain position. Generally, the termination position of the liquid phase is called the liquid phase termination line. After passing the termination line, the solid particles continue to advance until cleared. When the drilling fluid shaker is working normally and stably, the liquid phase termination line is generally located at 2/3 to 3/4 of the effective length of the screen.

The screening process actually includes two kinds of motion: liquid phase screening and solid phase transport forward on the screen surface. In the drilling shaker operation, the solid phase is mainly the cuttings or cuttings with extremely irregular shape and size, and the drilling fluid is generally a non-Newtonian fluid with specific rheology. At the same time, solid particles are wet particles immersed in drilling fluid and still wrapped by drilling fluid after separation. The structure and parameters of vibrating screen and screen, and the performance of drilling fluid will directly affect the screening process.

In order to ensure the normal operation of solid-liquid separation on the screen, no matter whether the solid particles are submerged in the drilling fluid or after being separated, they need to have a certain forward migration speed. When the solid phase is submerged, the migration speed is too small, it is easy to block the screen, reduce the processing capacity, and even cause the loss of drilling fluid. When the solid phase is separated, the slow migration rate will increase the probability of small particles passing through the screen, and even form solid particles accumulation on the screen surface, so that the screen is damaged early due to excessive load