Mud pump basics about working principle, types & properties

What is a mud pump?

Mud pump refers to a machine that transports flushing fluids such as mud or water into the borehole during the drilling process. Mud pumps are an important part of drilling equipment.

In the commonly used positive circulation drilling, it is to send the surface flushing medium-water, mud or polymer flushing liquid directly to the bottom of the drill bit through the high-pressure hose, the water tap and the center hole of the drill string under a certain pressure to achieve The purpose of cooling the drill bit, removing the cuttings and transporting them to the surface.

The commonly used mud pump is of piston type or plunger type. The crankshaft of the pump is driven by the power machine to rotate, and the crankshaft drives the piston or plunger to reciprocate in the pump cylinder through the crosshead. Under the alternate action of the suction and discharge valves, the purpose of pressurizing and circulating the flushing liquid is realized.

How does drilling mud pump work?

A mud pump is a machine that delivers flushing fluids such as mud or water to the borehole during oil drilling. It is an important part of drilling equipment. In the process of oil drilling, the mud pump injects the mud into the well with the drilling bit. Wastes such as cuttings are brought back to the surface to clean the well.

Oil drilling generally adopts positive circulation drilling. Under a certain pressure, the mud pump sends clean water, mud or polymer to the bottom of the drilling through water, high-pressure hose and the center hole of the drill string. At present, the commonly used mud pumps are piston pump and plunger pump, among which piston pump is also called electric reciprocating pump. Its working principle is to rely on the reciprocating motion of the piston, so that the working volume of the pump chamber changes periodically, and then the liquid is sucked and discharged. It is composed of pump cylinder, piston, inlet and outlet valves, inlet and outlet pipes, connecting rods and transmission devices.

It is more suitable for drilling operations with high pressure and small flow. The plunger pump is one of the important devices in the hydraulic system. Its working principle is to rely on the reciprocating movement of the plunger in the cylinder body to change the volume of the sealed working cavity to realize the process of oil absorption and oil pressure. It is more suitable for high-pressure, large-flow drilling operations.

Types of oil well mud pump

1. Press the function

Single-acting mud pump: only one suction and discharge action is completed in one cycle of the piston reciprocating motion.

Double-acting mud pump: completes two suction and discharge actions in one cycle of piston reciprocating motion.

2. According to the number of cylinders

According to the number of cylinders of the pump, there are single cylinder, double cylinder, triple cylinder, five cylinder and other types.

Performance index of oilfield mud pump

The two main parameters of mud pump performance are displacement and pressure.

1. Displacement

The displacement is calculated by several liters per minute, which is related to the diameter of the borehole and the required rate of flushing fluid returning from the bottom of the hole, that is, the larger the hole diameter, the larger the required displacement. It is required that the upward return speed of the flushing fluid can flush the cuttings and rock powder cut by the drill bit away from the bottom of the hole in time and carry them to the surface reliably. When drilling geological cores, the general upward return speed is about 0.4 to 1.0 m/min.

2. Stress

The pressure of the pump depends on the depth of the borehole, the resistance of the channel through which the flushing fluid passes, and the nature of the flushing fluid delivered. The deeper the hole is drilled, the greater the resistance of the line and the higher the pressure required.

With the change of the diameter and depth of the borehole, the displacement of the required pump can also be adjusted at any time. There is a gearbox in the pump mechanism or a hydraulic motor to adjust its speed to achieve the purpose of changing the displacement. In order to accurately grasp the changes of the pressure and displacement of the pump, a flow meter and a pressure gauge should be installed on the mud pump, so that the drillers can understand the operation of the pump at any time, and at the same time, judge whether the condition in the hole is normal through the pressure change to prevent the occurrence of in-hole ACCIDENT.

Mud pump performance characteristics

1. It can transport high concentration and high viscosity <10000PaS and suspended slurry containing particles.

2. The conveying liquid flow is stable, without overcurrent, pulsation, stirring and shearing of the slurry.

3. The discharge pressure has nothing to do with the rotation speed, and the low flow rate can maintain a high discharge pressure.

4. The flow is proportional to the rotational speed, and the flow can be adjusted through the speed change mechanism or the speed regulating motor.

5. The self-priming ability is strong, and the liquid can be directly pumped without installing a bottom valve.

6. The pump can be reversed, and the liquid flow direction is changed by the rotation direction of the pump, which is suitable for occasions where the pipeline needs to be flushed in the reverse direction.

7. Smooth operation, low vibration and low noise.

8. Simple structure, easy disassembly and maintenance.