Mud Pump Displacement and pump pressure
The typical structure of the mud pump is a double-cylinder double-acting pump, which is relatively reliable when used, but the volume and weight are large, the efficiency is low and the pressure fluctuates greatly. With the increase of drilling depth and the increase of casing level, the drilling pump displacement and pump pressure put forward higher and higher requirements. This also led to a sharp increase in pump power, pump weight and size also increased. In order to reduce the pump weight, then the design of the twin-cylinder pump is a greater improvement in steel and iron to reduce the pump. To steel plate is welded with steel plate instead of cast iron pump shell, and some parts to use high-quality alloy steel; reduce the pump width is the application of large diameter rolling bearings for connecting rod big end support, to abandon the cantilever crankshaft design. In this way, the center distance between the two cylinders is significantly reduced. These are the main improvements in the 1950s twin cylinders.
Of course, in addition to the details of the structure there are many improvements. Although the jet drilling process itself in the 1950s and 1960s proposed a pumping pressure of 521010 Pa, the actual continuous pump pressure of the twin cylinder pump can only reach about 515010 Pa. The main factor limiting the pump pressure increase is the life of the piston rubber bowl. Double cylinder double acting pump piston is "cover" in the cylinder, the cooling and cooling conditions are very poor. Although the rush is not high, but under the pressure due to the piston cup and cylinder liner friction, will still produce 100 ℃ up and down the temperature: plus a variety of wear between the cylinder liner, the cup quickly rupture, can not guarantee The normal operation of drilling operations and the use of reasonable life. However, this one-way piston and open cylinder structure to the suction has brought a special problem, that is, three-cylinder pump inhalation process, as long as the cylinder pressure is lower than the local atmospheric pressure, the air may be from behind the piston into the cylinder Destruction of normal inhalation.
So, in principle, the three-cylinder pump should be equipped with perfusion pump, which is also the usual practice abroad. Three-cylinder single-action mud pump has the advantage of small size, light weight, high efficiency, low pressure fluctuations, especially for drilling. Three-cylinder single-acting mud pump after 30 years of continuous improvement and improvement, in terms of performance, structure, reliability, adaptability and economy, has been mature, the use of the effect is also very significant. In China, the first pump was born in the fifties, for the twin pump. In the seventies, due to the drilling process of testing and promotion, the introduction of foreign three-cylinder pump and technology. Since then began the development of the three-cylinder pump, which in a few short years to replace the twin-cylinder pump, drilling wells to improve the level of the key equipment.