mud pump pressure problems in stock

The fluid end of a duplex or triplex pump offers hundreds of opportunities for error. The results of an error in such a high-pressure system can mean (1) expensive downtime on the pump and maybe the entire rig, (2) expensive repair-replacement, and (3) possible injury or death of a crewman or a company man. Under the laws of nature, pump pistons and liners will wear, and there will be some corrosion and metallurgical imperfections, but the majority of pump failures are manmade. Theoretically, thorough training and retraining should avoid most mud pump problems. Realistically, a critical failure analysis during repair will be necessary to determine how to correct the failure. Telltale signs of trouble are distortion of piston rods, frayed piston polymer, discoloration, odor, hard-to-remove piston, rod cracks, pitting, total fracture, valve seat wear, and unsuitable external appearance.

The positive displacement mud pump is a key component of the drilling process and its lifespan and reliability are critical to a successful operation.

The fluid end is the most easily damaged part of the mud pump. The pumping process occurs within the fluid end with valves, pistons, and liners. Because these components are high-wear items, many pumps are designed to allow quick replacement of these parts.

Due to the nature of its operation, pistons, liners, and valve assemblies will wear and are considered expendable components. There will be some corrosion and metallurgy imperfections, but the majority of pump failures can be traced back to poor maintenance, errors during the repair process, and pumping drilling fluid with excessive solids content.

A few signs include cut piston rubber, discoloration, pistons that are hard to remove, scored liners, valve and seat pitting or cracks, valve inserts severely worn, cracked, or completely missing, and even drilling fluids making their way to the power end of the pump.

The fluid end of a positive displacement triplex pump presents many opportunities for issues. The results of these issues in such a high-pressure system can mean expensive downtime on the pump itself and, possibly, the entire rig — not to mention the costly repair or replacement of the pump. To reduce severe vibration caused by the pumping process, many pumps incorporate both a suction and discharge pulsation dampener; these are connected to the suction and discharge manifolds of the fluid end. These dampeners reduce the cavitation effect on the entire pump which increases the life of everything within the pump.

The fluid end is the most easily damaged part of the mud pump. The pumping process occurs within the fluid end with valves, pistons, and liners. Because these components are high-wear items, many pumps are designed to allow quick replacement of these parts.

Additionally, the throat (inside diameter) can begin to wash out from extended usage hours or rather quickly when the fluid solids content is excessive. When this happens it can cut all the way through the seat and into the fluid end module/seat deck. This causes excessive expense not only from a parts standpoint but also extended downtime for parts delivery and labor hours to remove and replace the fluid module. With that said, a properly operated and maintained mud recycling system is vital to not only the pump but everything the drilling fluid comes in contact with downstream.

I’ve run into several instances of insufficient suction stabilization on rigs where a “standpipe” is installed off the suction manifold. The thought behind this design was to create a gas-over-fluid column for the reciprocating pump and eliminate cavitation.

When the standpipe is installed on the suction manifold’s deadhead side, there’s little opportunity to get fluid into all the cylinders to prevent cavitation. Also, the reciprocating pump and charge pump are not isolated.

The suction stabilizer’s compressible feature is designed to absorb the negative energies and promote smooth fluid flow. As a result, pump isolation is achieved between the charge pump and the reciprocating pump.

The isolation eliminates pump chatter, and because the reciprocating pump’s negative energies never reach the charge pump, the pump’s expendable life is extended.

Investing in suction stabilizers will ensure your pumps operate consistently and efficiently. They can also prevent most challenges related to pressure surges or pulsations in the most difficult piping environments.

Working with some of the world"s leading suppliers of low-pressure equipment, we offer low-pressure pump packages and agitating units to suit every operation.

Positive displacements pumps are generally used on drilling rigs to pump high pressure and high volume of drilling fluids throughout a drilling system. There are several reasons why the positive displacement mud pumps are used on the rigs.

The duplex pumps (Figure 1) have two cylinders with double acting. It means that pistons move back and take in drilling mud through open intake valve and other sides of the same pistons, the pistons push mud out through the discharge valves.

When the piston rod is moved forward, one of intake valves is lift to allow fluid to come in and one of the discharge valve is pushed up therefore the drilling mud is pumped out of the pump (Figure 2).

On the other hand, when the piston rod is moved backward drilling fluid is still pumped. The other intake and discharge valve will be opened (Figure 3).

The triplex pumps have three cylinders with single acting. The pistons are moved back and pull in drilling mud through open intake valves. When the pistons are moved forward and the drilling fluid is pushed out through open discharge valves.

On the contrary when the piston rods are moved backward, the intake valve are opened allowing drilling fluid coming into the pump (Figure 6). This video below shows how a triplex mud pump works.

Because each pump has power rating limit as 1600 hp, this will limit capability of pump. It means that you cannot pump at high rate and high pressure over what the pump can do. Use of a small liner will increase discharge pressure however the flow rate is reduces. Conversely, if a bigger liner is used to deliver more flow rate, maximum pump pressure will decrease.

As you can see, you can have 7500 psi with 4.5” liner but the maximum flow rate is only 297 GPM. If the biggest size of liner (7.25”) is used, the pump pressure is only 3200 psi.

Finally, we hope that this article would give you more understanding about the general idea of drilling mud pumps. Please feel free to add more comments.

Mud pump is one of the most critical equipment on the rig; therefore personnel on the rig must have good understanding about it. We’ve tried to find the good training about it but it is very difficult to find until we’ve seen this VDO training and it is a fantastic VDO training about the basic of mud pumps used in the oilfield. Total length of this VDO is about thirteen minutes and it is worth to watch it. You will learn about it so quickly. Additionally, we also add the full detailed transcripts which will acceleate the learning curve of learners.

Powerful mud pumps pick up mud from the suction tank and circulate the mud down hole, out the bit and back to the surface. Although rigs usually have two mud pumps and sometimes three or four, normally they use only one at a time. The others are mainly used as backup just in case one fails. Sometimes however the rig crew may compound the pumps, that is, they may use three or four pumps at the same time to move large volumes of mud when required.

Rigs use one of two types of mud pumps, Triplex pumps or Duplex pumps. Triplex pumps have three pistons that move back-and-forth in liners. Duplex pumps have two pistons move back and forth in liners.

Triplex pumps have many advantages they weight 30% less than a duplex of equal horsepower or kilowatts. The lighter weight parts are easier to handle and therefore easier to maintain. The other advantages include;

• One of the more important advantages of triplex over duplex pumps, is that they can move large volumes of mud at the higher pressure is required for modern deep hole drilling.

Triplex pumps are gradually phasing out duplex units. In a triplex pump, the pistons discharge mud only when they move forward in the liner. Then, when they moved back they draw in mud on the same side of the piston. Because of this, they are also called “single acting.” Single acting triplex pumps, pump mud at a relatively high speeds. Input horsepower ranges from 220 to 2200 or 164 to 1641 kW. Large pumps can pump over 1100 gallons per minute, over 4000 L per minute. Some big pumps have a maximum rated pressure of over 7000 psi over 50,000 kPa with 5 inch/127 mm liners.

Here is a schematic of a triplex pump. It has three pistons each moving in its own liner. It also has three intake valves and three discharge valves. It also has a pulsation dampener in the discharge line.

Look at the piston at left, it has just completed pushing mud out of the liner through the open discharge valve. The piston is at its maximum point of forward travel. The other two pistons are at other positions in their travel and are also pumping mud. But for now, concentrate on the left one to understand how the pump works. The left piston has completed its backstroke drawing in mud through the open intake valve. As the piston moved back it instead of the intake valve off its seat and drew mud in. A strong spring holds the discharge above closed. The left piston has moved forward pushing mud through the now open discharge valve. A strong spring holds the intake valve closed. They left piston has completed its forward stroke they form the length of the liner completely discharging the mud from it. All three pistons work together to keep a continuous flow of mud coming into and out of the pump.

Crewmembers can change the liners and pistons. Not only can they replace worn out ones, they can also install different sizes. Generally they use large liners and pistons when the pump needs to move large volumes of mud at relatively low pressure. They use a small liners and pistons when the pump needs to move smaller volumes of mud at a relatively high pressure.

In a duplex pump, pistons discharge mud on one side of the piston and at the same time, take in mud on the other side. Notice the top piston and the liner. As the piston moves forward, it discharges mud on one side as it draws in mud on the other then as it moves back, it discharges mud on the other side and draws in mud on the side it at had earlier discharge it. Duplex pumps are therefore double acting.

Double acting pumps move more mud on a single stroke than a triplex. However, because of they are double acting they have a seal around the piston rod. This seal keeps them from moving as fast as a triplex. Input horsepower ranges from 190 to 1790 hp or from 142 to 1335 kW. The largest pumps maximum rated working pressure is about 5000 psi, almost 35,000 kPa with 6 inch/152 mm linings.

A mud pump has a fluid end, our end and intake and the discharge valves. The fluid end of the pump contains the pistons with liners which take in or discharge the fluid or mud. The pump pistons draw in mud through the intake valves and push mud out through the discharge valves.

The power end houses the large crankshaft and gear assembly that moves the piston assemblies on the fluid end. Pumps are powered by a pump motor. Large modern diesel/electric rigs use powerful electric motors to drive the pump. Mechanical rigs use chain drives or power bands (belts) from the rig’s engines and compounds to drive the pump.

A pulsation dampener connected to the pump’s discharge line smooths out surges created by the pistons as they discharge mud. This is a standard bladder type dampener. The bladder and the dampener body, separates pressurized nitrogen gas above from mud below. The bladder is made from synthetic rubber and is flexible. When mud discharge pressure presses against the bottom of the bladder, nitrogen pressure above the bladder resists it. This resistance smoothes out the surges of mud leaving the pump.

Here is the latest type of pulsation dampener, it does not have a bladder. It is a sphere about 4 feet or 1.2 m in diameter. It is built into the mud pump’s discharge line. The large chamber is form of mud. It has no moving parts so it does not need maintenance. The mud in the large volume sphere, absorbs this surges of mud leaving the pump.

A suction dampener smooths out the flow of mud entering into the pump. Crewmembers mount it on the triplex mud pump’s suction line. Inside the steel chamber is a air charged rubber bladder or diaphragm. The crew charges of the bladder about 10 to 15 psi/50 to 100 kPa. The suction dampener absorbs surges in the mud pump’s suction line caused by the fast-moving pump pistons. The pistons, constantly starts and stops the mud’s flow through the pump. At the other end of the charging line a suction pumps sends a smooth flow of mud to the pump’s intake. When the smooth flow meets the surging flow, the impact is absorbed by the dampener.

Workers always install a discharge pressure relief valve. They install it on the pump’s discharge side in or near the discharge line. If for some reason too much pressure builds up in the discharge line, perhaps the drill bit or annulus gets plugged, the relief valve opens. That opened above protects the mud pump and system damage from over pressure.

Some rig owners install a suction line relief valve. They install it on top of the suction line near the suction dampener. They mount it on top so that it won’t clog up with mud when the system is shut down. A suction relief valve protects the charging pump and the suction line dampener. A suction relief valve usually has a 2 inch or 50 mm seat opening. The installer normally adjusts it to 70 psi or 500 kPa relieving pressure. If both the suction and the discharged valves failed on the same side of the pump, high back flow or a pressure surge would occur. The high backflow could damage the charging pump or the suction line dampener. The discharge line is a high-pressure line through which the pump moves mud. From the discharge line, the mud goes through the stand pipe and rotary hose to the drill string equipment.

However, even a properly installed pump can sometimes have problems, such aspriming, pressure, pulsation, noise or oil consumption problems.If you feel that the pump is not performing as it should, you must take immediate action to understand the cause of malfunctioning and restore it.

In this article we have summarized the most common problems that may occur during the normal use of a diaphragm pump and the necessary actions tofix them.

Don"t panic, before starting to dismantle your pump always check that the control regulator is in "by-pass" mode, this problem is very often due to inattention.

Problems on the suction line, i.e. pipes or fittings are sucking in air. The entire suction line must then be inspected and it must be ensured that pipes and fittings are securely fastened.

If the pressure continues to remain low or equal to zero, the problem may probably concern the nozzles; if the nozzles are worn or with a flow rate exceeding that which can be reached by the pump, they must be replaced.

The pulsation dampener may be set incorrectly. The dampener absorbs vibrations generated by the oscillating movement of the diaphragms thanks to a pressure chamber. If not set correctly, the dampener pressure can affect the pump pressure. Simply restore the correct pressure inside the dampener and the pump pressure will be regular again.

Another cause may be theincorrect configuration of the pressure regulator,check the pressure setting of the regulator (and if necessary, repair or replace it).

The diaphragms separate the pumping chamber from the transmission, preventing the pumped fluid from coming into contact with the mechanical parts and the oil; when the diaphragm breaks, the fluid filters in the oil making it milky.

Cavitation is an undesirable condition that reduces pump efficiency and leads to excessive wear and damage to pump components. Factors that can contribute to cavitation, such as fluid velocity and pressure, can sometimes be attributed to an inadequate mud system design and/or the diminishing performance of the mud pump’s feed system.

When a mud pump has entered full cavitation, rig crews and field service technicians will see the equipment shaking and hear the pump “knocking,” which typically sounds like marbles and stones being thrown around inside the equipment. However, the process of cavitation starts long before audible signs reveal themselves – hence the name “the silent killer.”

Mild cavitation begins to occur when the mud pump is starved for fluid. While the pump itself may not be making noise, damage is still being done to the internal components of the fluid end. In the early stages, cavitation can damage a pump’s module, piston and valve assembly.

The imperceptible but intense shock waves generated by cavitation travel directly from the fluid end to the pump’s power end, causing premature vibrational damage to the crosshead slides. The vibrations are then passed onto the shaft, bull gear and into the main bearings.

If not corrected, the vibrations caused by cavitation will work their way directly to critical power end components, which will result in the premature failure of the mud pump. A busted mud pump means expensive downtime and repair costs.

Washouts are one of the leading causes of module failure and take place when the high-pressure fluid cuts through the module’s surface and damages a sealing surface. These unexpected failures are expensive and can lead to a minimum of eight hours of rig downtime for module replacement.

To stop cavitation before it starts, install and tune high-speed pressure sensors on the mud suction line set to sound an alarm if the pressure falls below 30 psi.

Although the pump may not be knocking loudly when cavitation first presents, regular inspections by a properly trained field technician may be able to detect moderate vibrations and slight knocking sounds.

Gardner Denver offers Pump University, a mobile classroom that travels to facilities and/or drilling rigs and trains rig crews on best practices for pumping equipment maintenance.

Severe cavitation will drastically decrease module life and will eventually lead to catastrophic pump failure. Along with downtime and repair costs, the failure of the drilling pump can also cause damage to the suction and discharge piping.

When a mud pump has entered full cavitation, rig crews and field service technicians will see the equipment shaking and hear the pump ‘knocking’… However, the process of cavitation starts long before audible signs reveal themselves – hence the name ‘the silent killer.’In 2017, a leading North American drilling contractor was encountering chronic mud system issues on multiple rigs. The contractor engaged in more than 25 premature module washes in one year and suffered a major power-end failure.

Gardner Denver’s engineering team spent time on the contractor’s rigs, observing the pumps during operation and surveying the mud system’s design and configuration.

The engineering team discovered that the suction systems were undersized, feed lines were too small and there was no dampening on the suction side of the pump.

Following the implementation of these recommendations, the contractor saw significant performance improvements from the drilling pumps. Consumables life was extended significantly, and module washes were reduced by nearly 85%.

Although pump age does not affect its susceptibility to cavitation, the age of the rig can. An older rig’s mud systems may not be equipped for the way pumps are run today – at maximum horsepower.

The mud pump pressure gauge is a specialized gauge for mud pumps. It is mainly used for the petroleum, coal, chemical industry, drilling industries. This new model is used in measuring pressure of high viscosity and easy crystal medium. The gauge is also used for measurement of stationary pressure. We provide a full range of gauges. Whether you are looking for it, we can accommodate your needs for land or offshore drilling rigs.

Mud Pump Pressure is extremely important to the drilling process. The Mud Pump Pressure Gauge enables the driller to monitor the pressure while drilling. Any unusual change in pressure will alert the driller of down hole problems. Pressure too low could indicate washed out pipe orbit nozzle, loose joint or broken drill string, worn pump packing or liners, or lost returns due to formation breakdown. Pressure too high could indicate a plugged drill bit or an increase in mud density or viscosity. Reliable indication of mud pump pressure provides an early warning of circulation problems, enabling the driller to make corrections avoiding major problems.

Are you going to be using a pressure washer for high-pressure applications? Blasting oil and fats off concrete or brick walls? Removing graffiti from the outside of your building? Cleaning your industrial machinery?

Or maybe you’re going to be using a pressure washer for lower-pressure applications? Washing the sides of your house? Washing the family car? Washing the mud off your kids in the backyard—okay, that one is probably a criminal act, so don’t do it. Soft washing your roof?

Different types of pumps have different applications they work best for. The text below describes the differences and similarities between types of pumps, and the different applications each is best suited for.

For the most part, these two types of pumps function the same way. Both are reciprocating positive displacement pumps which pull water through an intake valve and into a chamber and push it—pressurized—back out through an outflow valve. These valves are engineered to be one-way only, meaning the intake valve will only open under negative pressure and the outflow valve will only open under positive pressure.

Duplex pumps have two pistons or plungers while triplex pumps contain three. This means duplex pumps must move faster to generate the same pressure levels as triplex pumps, consequently wearing their parts faster, and often causing a pulsating effect.

Triplex pumps last longer because each individual component has to do less work. Furthermore, the flow of water from triplex pumps is more constant, lessening the components’ strain even more.

Plunger pumps use a reciprocating plunger to pressurize water and force it through the outlet valve. The plunger is normally made out of hard ceramic, which is very durable and resistant to wear.

The plunger is attached via connecting rod to a rotor. As the ceramic plunger reciprocates out, it creates suction pressure drawing fluid through the intake. As the rotor turns, the plunger is pushed back down to send fluid through the outflow valve.

Similar to plunger pumps, piston pumps use reciprocating pistons to pressurize water and force it through the outlet valve. The difference between a piston and plunger pumps is the high-pressure seal. In a piston pump, the seal is attached to and reciprocates along with the piston.

Because of this, piston pump seals wear out faster and cannot handle as much pressure compared to plunger pumps. As the seal wears out, the power washer will suffer from reduced pressure buildup, resulting in a weakened stream and inefficient operation.

Pump failure is rarely the cause of power washer problems. The leading causes of pressure washer problems are system restrictions, which cause the pump to fail.

If the inlet hose or valve is not getting enough water to the pump, air is sucked in—this is called cavitation. When this mixture of water and air bubbles is pressurized it creates small explosions, damaging the pump and its components.

The easiest way to combat cavitation is to install a quality inlet valve and filter. This is especially true if the inlet source is a water tank, where many larger particles may sit and settle. If you are using particulates, such as sand, to assist with surface cleaning, make sure to use an appropriately-sized filter mesh to prevent clogging; you must also make sure your pressure washer has enough power to make sure the sand does not wash back into the machine, whereby ruining the pump.

Taken care of properly, with regular maintenance checkups, your pressure washer pump should last at least as long as the hour-rating it’s supposed to last for as per the owner’s manual. As we’ve said, actual pump failure is rarely the cause of the problem, but rather the result. Give us a call or submit a contact form with your questions, and we’ll do our very best to give you the right answer.

Mud Pump Pressure is extremely important to the drilling process. The Mud Pump Pressure Gauge enables the driller to monitor the pressure while drilling. Any unusual change in pressure will alert the driller of down hole problems. Pressure too low could indicate washed out pipe or bit nozzle, loose joint or broken drill string, worn pump packing or liners, or lost returns due to formation breakdown. Pressure too high could indicate a plugged drill bit or an increase in mud density or viscosity. Reliable indication of mud pump pressure provides an early warning of circulation problems, enabling the driller to make corrections avoiding major problems.