Principle, Performance and Classification of Mud Pump

Principle of Mud Pump

Mud pump is a mechanical device used in drilling to transport mud or water to the drill hole. It is an important component of drilling machinery equipment. Its main function is to inject mud into the wellbore using the drill bit during the drilling process, cool the drill bit, clean the drilling tools, stabilize the wellbore, drive the drilling, and bring back the rock cuttings to the surface after drilling.

In commonly used positive circulation drilling, mud pump uses freshwater as the flushing medium on the surface. Under certain pressure, mud or polymer flushing liquid is directly sent to the bottom of the hole through a high-pressure hose, the center hole of a faucet, and a drill column. The purpose is to cool the drill bit, remove the cuttings, and transport them to the surface.

The commonly used mud pump is a piston or plunger pump. The power machine drives the crankshaft of the pump to rotate. The crankshaft drives the piston or plunger to perform reciprocating motion in the pump cylinder. With the alternating action of the suction and exhaust valves, the purpose of pressurizing and circulating flushing liquid is achieved.

Performance of Mud Pump

The two main parameters of the performance of mud pump are displacement and pressure. Displacement is calculated in liters per minute, and it is related to the borehole diameter and the return speed of flushing fluid from the hole bottom. That is, the larger the borehole, the larger the required displacement. The requirement for the return speed of the flushing fluid is to flush out the rock cuttings and rock dust from the bottom of the hole in time and reliably bring them to the surface.

When drilling for geological rock core, the usual return speed is about 0.4 to 1 meter per minute. The pump pressure depends on the depth of the borehole, the resistance of the channel through which the flushing fluid passes, and the properties of the transported flushing liquid. The deeper the borehole, the greater the pipeline resistance, and the higher the pressure requirement.

With the increase of borehole diameter and changes in depth, the displacement of mud pump can also be adjusted at any time. The gearbox is installed in the pump mechanism, or its speed is adjusted by a hydraulic motor to achieve the purpose of changing the displacement.

In order to accurately grasp the changes in the pressure and displacement of the pump, a flow meter and pressure gauge should be installed on the mud pump to enable the drilling personnel to understand the operation of the pump at any time, and to identify the abnormal conditions inside the hole through pressure changes to prevent accidents inside the hole.

Classification of Mud Pump

Mud pump is divided into single-acting and double-acting types. The single-acting mud pump only completes one suction and discharge action in a cycle of the piston's reciprocating motion. The double-acting mud pump completes two suction and discharge actions in each reciprocating motion. If classified according to the number of cylinders, there are three types: single-cylinder, double-cylinder, and three-cylinder.

Sewage mud pump is a single-stage, single-suction, vertical centrifugal pump. The main components are volute, impeller, pump seat, pump shell, support cylinder, hydraulic motor seat, hydraulic motor, etc. Volute, pump seat, hydraulic motor seat, and impeller nut are made of high-quality steel casting, with good corrosion resistance and convenient processing technology.

To reduce weight and reduce lathe work, the pump shaft is made of high-quality carbon steel cold-drawn round steel. The mud pump seat is equipped with four skeleton oil seals and shaft sleeves to prevent shaft wear and extend the service life of the shaft. Mud pumps can be used vertically or inclined, occupying a small footprint. The volute can be exposed to the working medium, easy to start, no need for water intake, and the rotating direction should work clockwise when viewed from the outlet. The length of rubber hoses and fire hoses has various specifications for the convenience of the user.