Geological or seismic exploration, extraction of oil, gas and other minerals, laying water intakes, construction and some other technical work is impossible without drilling canals and wells in the ground. In the process of drilling the rock is destroyed by special installations consisting of a motor with a rotating rotor. The mechanical development of the rock is carried out with a strong bit.
What is a chisel?
In people who are not related to mining, this tool is most often associated with a manual tool intended for processing wood species. Today, a drill bit has absolutely nothing to do with carpentry tools. But the early drilling techniques necessary for sinking bore holes resembled woodwork with carpentry.
At that time, the drill bit resembled the joiner's tool. Modern technology has stepped forward, the appearance of drilling equipment has changed, and the term has been preserved.
Numerous upgrades have significantly expanded the capabilities of this tool. A variety of shapes and sizes of bits allows you to choose the drilling equipment for work of any type, significantly increasing the speed of drilling and the quality of wells. Modern manufacturers offer bits with a diameter of 46 mm to 1000 mm.
Drilling of the wells
In the process of rotation of the bit, at the same time as drilling fluid is introduced into the face under slight pressure , the soil is eroded and destroyed, forming a well of the required size and depth.
According to the methods of well formation, the drilling process is divided into three types:
- Continuous drilling, in which the rock is destroyed in one plane or in steps.
- Core drilling destroys the soil along the periphery of the face.
- Coring from a well.
For each type of work, bits in shape and size are made of high quality durable metal alloys.
Drill bit structure
The operation of a screw or progressive-impact drilling rig is impossible without the installation of a bit. What it is? Monolithic strong matrix or rod base, equipped with elements for drilling rock.
Depending on the purpose of the bit, metal blades or drill bits are used. The rotation of the matrix rotary installation can be combined with rotational movements of the heads. A variety of types of installations and types of drilling devices make it possible to develop any type of rock. Especially in demand are bits in the oil and gas industries.
Types of bits for impact on the ground
Crushing - like roller cone bits are used to develop rocks of any density. Rotating around its axis and around the main core, wedge-shaped cones destroy solid rock by crushing and cleaving the soil. They are used in various industries, mainly for oil and gas production, as well as for drilling blasting and exploration wells.
Cutting abrasive - these are diamond nozzles with carbide pins, which are used when passing wells in hard rocks or mixed soils. By design, there are step, spiral and radial. For a firm hold on the cutting diamond coating, the head matrix is made of metal powder.
Cutting and chipping - such blade nozzles are used for drilling wells up to 30 meters deep in loose and loose rocks. The blades tilted towards the rotor rotation destroy the soft soil, cutting and chipping its layers. Most often used for drilling exploration wells and require mandatory cleaning of the face by washing or with a screw device.
Roller bit - what is it?
Such a nozzle is used when drilling engineering-geological, exploration, production, prospecting and other types of wells. The widespread use of roller cone bit due to the ability to carry out drilling work in soils with any level of hardness. A quarry machine designed for rotary drilling is equipped with a roller cutter. What it is? Chisel with pressed or milled teeth and pins of various configurations and lengths made of tungsten carbide.
Roller cone bits consist of:
- cone;
- bearings;
- paws (sections);
- teeth.
The central base (paw), as a rule, has an adjustable tilt. The cones are fixed on it at a certain angle to the outside or inside of the structure. The number of installed cones depends on the type of paws and their number. Up to 6 cones rotating at a speed of 250 revolutions per minute can be placed on one bit. Uninterrupted rotation of the heads is ensured by constant lubrication of the bearings, which create conditions for their oscillating or sliding movements.
Types of cone heads
By design, cone bits are divided into two groups:
- Whole-body - characterized by welded paws and cones.
- Sectional - are welded from two, three or four separate paws.
The section drill bit is attached to the drill string by an external taper thread, and the body bit is internal.
According to the principle of interaction with the mountain breed are divided into:
- Crushing. Drilling is characterized by the absence of milling interaction of the peripheral teeths with the wall of the well with their minimal sliding along the bottom during rolling cone rolling. Crushing bits are used in hard, strong, abrasive, very strong rocks and their various combinations.
- Crushing-chipping. In the process of rolling cones along the walls of the face, drilling is characterized by an increase in the sliding of the teeth. Shot blasting chisels are used in soft rocks and in soils with medium hard formations and abrasive soils.
L-shaped or T-shaped peripheral crowns significantly reduce the wear of the heads in diameter. The practical design of roller cone bits is used on soils of any type. The price of a bit with cones depends on various parameters: the quality of the metal from which the nozzles are made, the number and size of cones, and the design features of the paws. The simplest modifications cost about 15-18 thousand rubles, the purchase of more expensive ones will cost 40-45 thousand rubles.
Three-cone nozzles
A cone drill bit may consist of one, two, three, four or six cones of cylindrical, conical or spherical shape. For drilling deep wells, a single-cone bit is mainly used. The three-cone bit consists of three sections. Each section of the three-cone bit has a paw in the form of a dihedral angle (120 0 ), a thrust bearing, a nozzle of the hydraulic monitor channel, a locking finger and a cone with teeth. In cross section 3, the legs joined together form a circle. Rotating and making translational movements, the chisel moves through the rock. Drilling mechanism with cones destroys it, making rotary movements simultaneously with the bit.
Most often, three-cone bits are used in drilling operations in oil and gas fields. In addition, triple heads are actively used in construction, when drilling holes and water wells, for drilling holes during seismic exploration and in many other types of work.