Horizontal directional drilling is one of the most popular methods for creating wells, which is used during repair work, laying communication lines under existing transport routes. When using this method of drilling, insignificant destruction of the earth mass occurs, which favorably affects its stability and bearing capacity.
One of the main elements of the installations involved in the creation of both vertically and horizontally directed wells is the swivel. Without this mechanism, it is impossible to carry out work on spot mining of soil. Proper use of it allows you to get wells of the required dimensions with an accuracy of 10 millimeters.
Appointment
Any drilling rig consists of three main elements - a tackle system, a swivel and a drill string. The tackle system is a support structure that is pronounced when creating vertical wells. It performs the functions of moving drilling equipment, creates the force necessary for immersion in the soil of the equipment and is responsible for the stability of the entire installation.
A rotor is installed on the tackle system, which rotates the column (rod with nozzle) with a drill for excavating. The swivel is an intermediate link between these two elements. It is necessary to maintain the weight of the drill string, supply flushing fluid and prevent twisting of the ropes. In horizontally directed drilling, the swivel is attached to the elevator slings - a mechanism connecting the string to a device that moves the drill in a given plane. There are three main types of swivel - flushing, power and operational. Each type has its own characteristics.
Swivel Swivel
Flushing drilling swivel serves to supply the solution to the site of excavation. Structurally, it is an elongated hollow cylinder, which is placed in a streamlined metal casting, or casing. The frame is attached to the rotor using a hinge, or the so-called earrings.
There is a special branch in the flushing swivel housing, to which a hose for supplying liquid is connected. The solution, having passed under high pressure through the hollow cylinder of the described device, enters the rotating column, and then into the face itself. The process of leaching the soil begins. A flushing or bentonite drill plow is characterized by its ability to transmit force through its body. Based on this indicator, installations for 20, 30, 50 and more tons are distinguished.
Operational and power swivel
The power subtype of the devices is used at the final stage of the drilling process. Its upper edge has rotational equipment and a drive. With their help, the swivel takes on the functions of the rotor, reducing costs and accelerating well production. Models of this subtype differ in power and type of docking element. The operational type of devices performs two functions at once - the creation of rotational force (using the built-in device) and the supply of flushing solution. You can perform any downhole work if you connect the drill string and the swivel presented. The drilling rig obtained by such a combination will not be inferior in productivity to professional equipment.
Drill Swivel Requirements
The drilling swivel is nothing more than a connecting unit designed to operate in difficult conditions. It must maintain tightness when a large pressure occurs in the circulation system of the drilling rig. In addition, it must endure alternating and unstable loads.
During the rotation of the drill string, both static overloads and dynamic stresses arise, which the installation must cope with. Moreover, the drill swivel must have anti-corrosion protection and a special coating to increase wear resistance.
Features of choice
For effective and efficient drilling, it is important that the swivel meets all the requirements described above. In addition, it must also meet the basic standards for this type of equipment:
- The transverse dimensions should not impede movement along the tackle system during tripping, as well as the extension of the drill string.
- The coupling with the bearing block of the drill tower must be reliable and convenient for dismantling the equipment after completion of work.
- Lubricant should be evenly distributed throughout the structure so that the swivel for a small-sized drilling rig does not overheat.
In order to increase drilling productivity, it is recommended to choose equipment whose components can be quickly and easily replaced with heavy wear. It is important to remember that it is the reliability and durability of the swivel that determines the performance and service life of the entire drilling rig.
Conclusion
Even if you plan to develop a well in your area, it is not recommended to assemble the swivel with your own hands. This is a sophisticated equipment that is subject to increased wear resistance requirements. The operation of the entire drilling rig depends on its durability and reliability, starting from the tackle system and ending with the rotor, drill rod and drill. Special projects should be carried out according to drawings agreed with an experienced designer. They contain information regarding tolerances and treatments that will ensure long-term operation of the unit, taking into account the operational characteristics of all elements of the drilling rig.