Manufacturers of pneumatic water well drilling rigs understand that different methods should be adopted when the rigs encounter different geological formations during drilling to achieve good results. Various geological formations may be encountered, such as quicksand layers and gypsum layers. Once gypsum intrusion occurs during the drilling process of pneumatic water well drilling rigs, calcium ions can be removed by adding sodium carbonate, calcium removal, viscosity reduction and other methods. At the same time, viscosity reducers with strong calcium resistance can be used to control viscosity reduction and make up for the deficiencies of materials such as fluid loss reducers and anti-collapse agents.

• Gypsum layer

Before drilling through the gypsum layer, pretreat the drilling fluid of the drilling rig, reduce the solid phase and viscosity, and add gypsum-resistant treatment agents (such as sodium carbonate, calcium removers, viscosity reducers, etc.). Meanwhile, prepare the treatment agents for handling the gypsum layer in advance based on the construction materials used in adjacent wells. Increase the pH value of the drilling fluid of the water well drilling rig to further enhance the small water well drilling rig’s resistance to gypsum contamination.

• Quicksand layer

When drilling in quicksand formations, it is necessary to increase the viscosity of the drilling fluid and the bentonite content in the drilling fluid of the water well drilling rig, which is generally required to be above 10%. To improve the wall-building performance of the drilling fluid of the water well drilling rig, appropriately reducing the displacement in the project can reduce the erosion of the quicksand formation. Before tripping out, the section must be sealed with thick mud with a viscosity greater than 80 to ensure the smooth tripping, electrical logging and casing running of the drilling machinery of the small water well drilling rig.

• Quartz sandstone

Quartz sandstone is an extremely hard rock, and slow drilling progress often occurs during the drilling process. It may produce two meters of sand when drilling one meter, accompanied by severe drilling tool vibration, excessive slag entrapment and rock cutting, as well as drill sticking failures. Therefore, it is necessary to have a detailed understanding of the terrain.

Clear water does not have the same lubricity as drilling mud. Drilling tools vibrate violently in hard rock, and the rock breaks when the drilling tools vibrate. Clear water has strong selectivity, so the flushing fluid cannot carry the increasingly large cuttings out of the hole. Sand-like cuttings keep floating and sinking in the hole. If a powder extraction pipe is used, the phenomenon of producing two meters of sand when drilling one meter may occur. A slight carelessness may lead to drill sticking, and excessive sand will bring more troubles to hole cleaning.

Quartz sandstone is formed by sedimentation and belongs to an extremely hard rock. Small pneumatic water well drilling rigs drill relatively shallow holes (30–200 meters), so diamond drill bits are generally used for clear water drilling with automatic mud making. This often results in slow drilling progress—drilling one meter may produce two meters of sand—along with severe drilling tool vibration, frequent slag entrapment and rock spalling, and drilling failures such as drill sticking.

Solution: If mud drilling is uneconomical, the occurrence of sand production can be reduced by reducing the vibration of small water well drilling rigs. Nitro acid-base additives can be added to clear water to achieve vibration reduction and lubrication effects, which can reduce the rig’s vibration and sand production. Then, persist in cleaning the borehole of the pneumatic water well drilling rig to ultimately solve the problem!