mud pump selection criteria in stock

When choosing a size and type of mud pump for your drilling project, there are several factors to consider. These would include not only cost and size of pump that best fits your drilling rig, but also the diameter, depth and hole conditions you are drilling through. I know that this sounds like a lot to consider, but if you are set up the right way before the job starts, you will thank me later.

Recommended practice is to maintain a minimum of 100 to 150 feet per minute of uphole velocity for drill cuttings. Larger diameter wells for irrigation, agriculture or municipalities may violate this rule, because it may not be economically feasible to pump this much mud for the job. Uphole velocity is determined by the flow rate of the mud system, diameter of the borehole and the diameter of the drill pipe. There are many tools, including handbooks, rule of thumb, slide rule calculators and now apps on your handheld device, to calculate velocity. It is always good to remember the time it takes to get the cuttings off the bottom of the well. If you are drilling at 200 feet, then a 100-foot-per-minute velocity means that it would take two minutes to get the cuttings out of the hole. This is always a good reminder of what you are drilling through and how long ago it was that you drilled it. Ground conditions and rock formations are ever changing as you go deeper. Wouldn’t it be nice if they all remained the same?

Centrifugal-style mud pumps are very popular in our industry due to their size and weight, as well as flow rate capacity for an affordable price. There are many models and brands out there, and most of them are very good value. How does a centrifugal mud pump work? The rotation of the impeller accelerates the fluid into the volute or diffuser chamber. The added energy from the acceleration increases the velocity and pressure of the fluid. These pumps are known to be very inefficient. This means that it takes more energy to increase the flow and pressure of the fluid when compared to a piston-style pump. However, you have a significant advantage in flow rates from a centrifugal pump versus a piston pump. If you are drilling deeper wells with heavier cuttings, you will be forced at some point to use a piston-style mud pump. They have much higher efficiencies in transferring the input energy into flow and pressure, therefore resulting in much higher pressure capabilities.

Piston-style mud pumps utilize a piston or plunger that travels back and forth in a chamber known as a cylinder. These pumps are also called “positive displacement” pumps because they literally push the fluid forward. This fluid builds up pressure and forces a spring-loaded valve to open and allow the fluid to escape into the discharge piping of the pump and then down the borehole. Since the expansion process is much smaller (almost insignificant) compared to a centrifugal pump, there is much lower energy loss. Plunger-style pumps can develop upwards of 15,000 psi for well treatments and hydraulic fracturing. Centrifugal pumps, in comparison, usually operate below 300 psi. If you are comparing most drilling pumps, centrifugal pumps operate from 60 to 125 psi and piston pumps operate around 150 to 300 psi. There are many exceptions and special applications for drilling, but these numbers should cover 80 percent of all equipment operating out there.

The restriction of putting a piston-style mud pump onto drilling rigs has always been the physical size and weight to provide adequate flow and pressure to your drilling fluid. Because of this, the industry needed a new solution to this age-old issue.

As the senior design engineer for Ingersoll-Rand’s Deephole Drilling Business Unit, I had the distinct pleasure of working with him and incorporating his Centerline Mud Pump into our drilling rig platforms.

In the late ’90s — and perhaps even earlier —  Ingersoll-Rand had tried several times to develop a hydraulic-driven mud pump that would last an acceptable life- and duty-cycle for a well drilling contractor. With all of our resources and design wisdom, we were unable to solve this problem. Not only did Miller provide a solution, thus saving the size and weight of a typical gear-driven mud pump, he also provided a new offering — a mono-cylinder mud pump. This double-acting piston pump provided as much mud flow and pressure as a standard 5 X 6 duplex pump with incredible size and weight savings.

The true innovation was providing the well driller a solution for their mud pump requirements that was the right size and weight to integrate into both existing and new drilling rigs. Regardless of drill rig manufacturer and hydraulic system design, Centerline has provided a mud pump integration on hundreds of customer’s drilling rigs. Both mono-cylinder and duplex-cylinder pumps can fit nicely on the deck, across the frame or even be configured for under-deck mounting. This would not be possible with conventional mud pump designs.

The second generation design for the Centerline Mud Pump is expected later this year, and I believe it will be a true game changer for this industry. It also will open up the application to many other industries that require a heavier-duty cycle for a piston pump application.

The purpose of this article is to present some guidelines and simplified techniques to size pumps and piping typically used in mud systems. If unusual circumstances exist such as unusually long or complicated pipe runs or if very heavy or viscous drilling muds are used, a qualified engineer should analyze the system in detail and calculate an exact solution.

To write about pumps, one must use words that are known and well understood. For example, the label on the lefthand side of any centrifugal pump curve is Total Head Feet. What does this mean?

Total Head remains constant for a particular pump operated at a constant speed regardless of the fluid being pumped. However, a pump’s pressure will increase as the fluid density (mud weight) increases according to the following relationship:

Note that the pump pressure almost doubled. It follows that the required pump horsepower has increased by the same percentage. If the pump required 50 HP for water service, it will require the following horsepower for 16 lb/gal mud:

To summarize, a pump’s Total Head remains constant for any fluid pumped, only the pump pressure and pump horsepower will change. Therefore, a pump motor must be sized according to the heaviest weight mud to be pumped.

In our example problem, the required desilter pressure head is 75 ft. for any mud weight. However, the pressure would be 30.3 PSIG for water or 43.6 PSIG for 12 lb mud or 58.1 PSIG for 16 lb mud. A good rule of thumb is that the required pressure (PSIG) equals 4 times the mud weight (12 LB/GAL x 4 = 48 PSIG).

Determine the required pressure head and flow rate. If the pump is to supply a device such as a mud mixing hopper or a desilter, consult the manufacturer’s information or sales representative to determine the optimum flow rate and pressure head required at the device. (On devices like desilters the pressure head losses downstream of the device are considered negligible and are usually disregarded.)

Select the basic pump to pump the desired flow rate. Its best to refer to a manufacturer’s pump curve for your particular pump. (See example – Figure 3).

The pump’s impeller may be machined to a smaller diameter to reduce its pressure for a given application. Refer to the manufacturer’s pump curves or manufacturer’s representative to determine the proper impeller diameter. Excessive pressure and flow should be avoided for the following reasons:

The pump must produce more than 75 FT-HD at the pump if 75 FT-HD is to be available at the desilter inlet and the pump’s capacity must be at least 800 GPM. Therefore, we should consider using one of the following pumps from the above list: 4″ x 5″ Pump 1750 RPM – 1000 GPM at 160 FT-HD; or 5″ x 6″ Pump 1750 RPM – 1200 GPM at 160 FT-HD.

The pump suction and discharge piping is generally the same diameter as the pump flange diameters. The resulting fluid velocities will then be within the recommended ranges of 4 to 10 FT/SEC for suction lines and 4 to 12 FT/

SEC for discharge lines. Circumstances may dictate that other pipe diameters be used, but remember to try to stay within the above velocity guidelines. Smaller pump discharge piping will create larger pressure drops in the piping

and the pump may not be able to pump the required amount of fluid. (For example, don’t use a 4″ discharge pipe on a 6″ x 8″ pump and expect the pump’s full fluid flow.)

6″ pipe may be used for the suction pipe since it is relatively short and straight and the pump suction is always flooded. 6″ pipe is fully acceptable for the discharge pipe and is a good choice since the desired header is probably 6″ pipe.

8″ pipe may be used for the suction pipe (V = 5.13 FT/SEC) since V is still greater than 4 FT/SEC. 8″ pipe would be preferred if the suction is long or the suction pit fluid level is low with respect to the pump.

A mud pump is a piston driven pump design that can produce high-pressure operations to safely transfer high viscosity fluids over an extended depth. The mud pump has many applications in industrial service, but it has proven to be invaluable in many drilling operations. Let"s take a look at mud pumps and why they are such a good fit for the industries they serve.

A Mud pump is a reciprocal pump design utilizing a piston in a cylinder to transfer fluids under high pressure. A mud pump can generate up to 7,500 psi (52,000 kPa) during normal operations. Mud pumps are a positive displacement design.

Mud pumps are available in a variety of configurations and sizes. However, mud pumps tend to be one of two main types: the duplex and the triplex. The duplex mud pump features two pistons (or plungers) in constant action to move the fluid.

The triplex mud pump has all but replaced the duplex version in most applications, although you will still find the latter in use in some smaller countries. The triplex mud pump features a triple piston (plunger) design that is more efficient than the duplex design.

The latest designs of the mud pump are the quintuplex and hex versions. As the name suggests, these designs feature five or six pistons in a reciprocating design. Although not in widespread use as compared to the triplex design, these mud pumps spread the pumping action across the rotational cycle, creating less mud noise. This allows for better measurements and logging to take place while in operation.

There are two main parts to a mud pump: the fluid end and the power end. The fluid end is where the actual pumping takes place. The components of the fluid end consist of valves, pistons (or plungers), and liners.

Since the fluid end is in constant contact with the material being pumped, most modern designs allow for quick replacement of worn components as needed. This dramatically extends the life of a unit without having to completely replace the pump.

The power end of a mud pump is responsible for taking the input power, typically through a driveshaft, and converting it into the reciprocating motion needed for the pistons. In most mud pump applications, the power end uses a crosshead crankshaft for this conversion.

Rotational power is supplied to the mud pump through an external power source. The power end of the pump converts this rotational energy through a crankshaft to a reciprocating motion that moves the pistons.

Due to the pressure and material being pumped, most mud pump applications can create a lot of vibration. To combat this, many mud pump applications incorporate pulsation dampeners. These are typically used on both suction and discharge sides of the pump.

In some cases, a positive displacement pump may pull the fluids at a pressure lower than its vapor pressure. When this happens, damaging cavitation can take place. In these cases, a charge pump might be required at the inlet side to maintain a positive pressure on the suction stream.

When selecting a mud pump, there are two main parameters to be used, pressure and displacement. Pressure is the net pumping pressure that the pump can safely provide. The requirement for pressure increases as the drilling depth and fluid (or slurry) viscosity increases.

Displacement is the volume of fluid that the pump can transfer within a given time period. In most applications, this is rated as discharged liters per minute.

Mud pumps are ideal wherever a lot of fluid needs to be pumped under high pressure. They are considered an essential part of most oil well drilling rigs. Mud pumps can deliver high concentration and high viscosity slurry in a stable flow, making them adaptable to many uses.

Mud pumps are an invaluable tool when high pressure and high viscosity fluids are needing to be transferred. Mader Electric, Inc. specializes in mud pump repair and installation, as well as pump training. Contact us to see how we can help with your pumping needs.

Rig pump output, normally in volume per stroke, of mud pumps on the rig is  one of important figures that we really need to know because we will use pump out put figures to calculate many parameters such as bottom up strokes,  wash out depth, tracking drilling fluid, etc. In this post, you will learn how to calculate pump out put for triplex pump and duplex pump in bothOilfield and Metric Unit.

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.

The 2,200-hp mud pump for offshore applications is a single-acting reciprocating triplex mud pump designed for high fluid flow rates, even at low operating speeds, and with a long stroke design. These features reduce the number of load reversals in critical components and increase the life of fluid end parts.

The pump’s critical components are strategically placed to make maintenance and inspection far easier and safer. The two-piece, quick-release piston rod lets you remove the piston without disturbing the liner, minimizing downtime when you’re replacing fluid parts.

abstractNote = {Based on extensive research, development, and field testing of mud pumps and accessory equipment, this book offers cost-saving methods in operation and maintenance of triplex and duplex pumps. It covers practical engineering concerns such as pressure losses from friction in the piping and inertia in the drilling mud; suction dampeners in pump operation; charging the suction pipe for greater efficiency and smoother operation; hydraulic and mechanical knocking; hydraulic pressure losses; discharge lines.},

Since horizontal directional drilling (HDD) work tends to be slower in the winter months, particularly when the ground is frozen, winter is a prime time to inspect the power end of the pump and prevent downtime on the job later.

If one waits until an audible problem can be detected, it is often very expensive to repair. All smaller HDD pumps – 100 hp and smaller — tend to use the same type of internal components regardless of the manufacturer.

The largest load bearing area of the pump is the crosshead pin and bushing area. Wear can be detected by locking the intermittent or piston rod with a pipe wrench and rotating the crank shaft slightly. If one can feel any slack it can only be coming from the pin and bushing or the connecting rod bearing. It then becomes necessary to remove the connecting rod assembly consisting of the connecting rod and cross head. If slack is determined in the pin bushing, it will be necessary to press out the pin and inspect the bushing and the crosshead pin in the eye of the connecting rod. Some manufacturers ship bushings that are designed to fit. Others ship them and they have to be reamed to fit the pin after the bushing is installed. The installation instructions and dimensional fits are provided by the manufacturer in the pump manual.

The next area of concern is the connecting rod bearings themselves. If visual wear can be seen, use a micrometer and measure the crankshaft journals to make sure they are not out of round. If the journals check out, then all is needed is new connecting rod bearings. Some manufactures utilize shims to get the correct fit to the journal. Others provide automotive style bearings that only require correct torque to the rod cap for correct installation. There are pros and cons concerning automotive style vs shim bearings. Shim type bearings does allow for oversized connecting rod bearing should the journals be worn. This allows for turning down the crank journals a few thousands and utilizing a larger connecting rod bearing. If a pump uses automotive style precision bearings and the journals are out of round, it is necessary to replace the crankshaft.

Wiper box packing keeps the oil within the power frame and external contamination from entering the power end. The packing is easy to inspect and essential for longevity of the power end. The wiper box packing must remain in excellent condition at all times. Allowing the pump to set for extended periods of time or letting external contamination build on the packing shortens the lifespan.

If one waits until an audible problem can be detected, it is often very expensive to repair. All smaller HDD pumps – 100 hp and smaller — tend to use the same type of internal components regardless of the manufacturer.

Inspection of the power end allows the owner to dictate when repairs are necessary rather than allowing the pump to dictate during the middle of a job when repair is required. If problems are detected early, repair is relatively inexpensive. If a problem is not detected early, that problem often leads to more unnecessary wear and affects other components of the pump. An early fix to any problem is relatively inexpensive. Allowing the problem to continue can often cost several thousands of dollars and downtime on a job.

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.

A comprehensive range of mud pumping, mixing, and processing equipment is designed to streamline many essential but time-consuming operational and maintenance procedures, improve operator safety and productivity, and reduce costly system downtime.

The design of a slurry pump is critical to making sure that the abrasive and often corrosive aspects of the slurry does not destroy the impeller. Additionally, slurry and sludge may contain large unforeseen solids that will inevitably clog many types of pumps. Since most centrifugal pumps have an impeller with a close tolerance to the volute, the abrasive and sometimes corrosive nature of the slurry will quickly wear the volute and ruin the tolerance. This, in turn, causes the pump to lose its suction capability. This causes massive downtime with slurry pumps along with costly maintenance and spare parts.

For this reason, the EDDY Pump is ideal for slurry pumping applications. The EDDY Pump does not have an impeller, but instead a rotor that does not have any critical tolerances. This allows it to pump slurry at rates of 30% and solids up to 12 inches. This is far more than what centrifugal pumps can handle without any failure or need to change wear parts.

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.