Impact type water well drilling rig

By relying on the vertical reciprocating motion of the drilling tool, the drill bit impacts the bottom of the well to break the rock layer. Its structure is simple, but there is no circulating well cleaning system, and the removal of rock debris cannot be carried out simultaneously with the drilling rig, resulting in low efficiency. The drilling depth is generally within 250 meters, and some can reach 500-600 meters. The main types are as follows. A simple impact drilling rig that uses the weight of the drilling tool itself to impact the formation. The lower end of the drilling tool consists of several sharp angled grab flaps that can be opened and closed. When the drilling tool moves downward under its own weight, the grab flaps open, and the tips of each grab flap cut into the rock layer on a circumference with a diameter of about 1 meter. Then, the drilling tool is lifted by a winch through a steel wire rope. During the closing process, the grab flaps grab the rock debris into the cone body, and after being lifted out of the wellhead, the grab flaps are opened to unload the rock debris. The drilling depth of the impact cone is usually 40-50 meters, and the deepest can reach 100-150 meters.
The wire rope impact drilling rig consists of a mast and its top lifting pulley, wire rope, impact mechanism, drilling tools (including drill rod and drill bit), electric motor, etc. (Figure 4). During operation, the electric motor drives the impact mechanism through the transmission device, which in turn drives the steel wire rope to make the drilling tool move back and forth up and down. When moving downwards, the weight of the drilling tool itself is used to make the drill bit cut into and break the rock layer, while when moving upwards, it is pulled by the steel wire rope. The height of the drilling tool's descent, also known as the stroke size, is determined according to the rock conditions, generally ranging from 0.5 to 1 meter, with the larger value used for hard rock layers; The commonly used impact frequency is 30-60 times per minute. The cut rock debris can be removed from the ground using a sand extraction cylinder, or a drilling tool that integrates a drill bit and a sand extraction cylinder can be used to drill and remove the rock debris simultaneously. The cut rock debris can be directly fed into the extraction cylinder, and when it is full, the drilling tool can be lifted to pour out the rock debris. To improve the wear resistance and drilling speed of the drill bit, tungsten steel powder is often deposited at the end of the drill bit to form an alloy welding drill bit. Composite drilling rig
There are two types: one is a dual-purpose water well drilling rig that adds an impact mechanism on the basis of a rotary drilling rig, mainly using rotary drilling, and when encountering pebble layers, uses impact drilling, which has strong adaptability to various formations; Another type is a water well drilling rig that combines impact and rotation, such as a pneumatic down the hole hammer drilling rig. The down the hole hammer drilling tool used (Figure 5) consists of a cylinder liner and a piston that moves up and down in the cylinder liner. The lower end of the cylinder liner is connected to the drill bit, and the upper end is connected to the drill rod through a threaded joint. The high-pressure air of 0.7-1.4 megapascals provided by the air compressor passes through the check valve above the piston, the air distributor, and the air inlet below the piston, pushing the piston to move back and forth at a frequency of 700-1200 times per minute, making the piston frequently impact the drill bit to enhance its ability to drill into rock formations. At the same time, the drilling tool rotates at a lower speed of 35-60 revolutions per minute. The air discharged from the upper and lower cavities of the piston enters the drill bit downwards, cooling the drill bit and carrying the rock debris at the bottom of the hole out of the wellhead. The structure of its rotating and circulating well washing part is basically the same as that of the rotary drilling rig that uses compressed air to wash the well, and the drill bits used are tungsten carbide ball tooth drill bits or roller drill bits. The pneumatic down the hole hammer drilling rig can be used for drilling deep wells in hard rock formations, with high drilling speed that does not decrease with increasing drilling depth, and the drilled wellbore is relatively straight.
In order to adapt to the needs of drilling in different formations and improve drilling efficiency, water well drilling rigs are developing towards multi-purpose drilling rigs and fully hydraulic transmission and control: that is, a drilling rig is equipped with multiple equipment and accessories, and can use various drilling methods such as impact, rotary, and down the hole hammer; Methods such as mud flushing, compressed air flushing, and forward/reverse circulation flushing can also be used.