mud pump design calculation for sale

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.

Learning about drilling fluids, mud pumps and conditioning equipment is required basic knowledge which personnel working on the rig must understand. In the old day, you may need to take a lot of time to learn this knowledge. Nowadays, Petroleum Extension Service publishes the book named “Drilling Fluids, Mud Pumps, and Conditioning Equipment” which will provide learners a lot of essential thing regarding drilling fluids, mud pumps and equipment. Today, I would like to review this book so you will know what inside and what you will you get from it.

Circulating systems on the drilling – function of drilling fluid and circulating system, hydraulic of mud circulating system, air circulating system, etc

Drilling mud– function of drilling mud, type of drilling mud used in drilling industry, composition of drilling mud, how to test drilling fluids, equipment for mud testing

Mud pumps – reciprocating pumps, configuration of Duplex and Triplex pumps, pump output, comparison of Triplex and Duplex pumps, operating and maintenance practices for the pumps

The book has the basic content with few simple calculations. It is good for new people who have less rig experience. It is not easy for less experience to understand everything in the oil field quickly; therefore, the book provides a lot of photos, drawings that will help learners to understand the content easily. You can see from the images which I capture from the book.

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.

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.

Centerline stuck with their original design through all of the typical trials and tribulations that come with a new product integration. Over the course of the first several years, Miller found out that even the best of the highest quality hydraulic cylinders, valves and seals were not truly what they were represented to be. He then set off on an endeavor to bring everything in-house and began manufacturing all of his own components, including hydraulic valves. This gave him complete control over the quality of components that go into the finished product.

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.

What type of drill bit are we using (roller cone with teeth or buttons, drag bit, PDC)? What are we using for a mud pump (centrifugal or piston)? How much flow (gallons per minute) and pressure (pounds per square inch) do we have available?

Hydraulics describes how fluid flow inside tubulars and annular spaces uses pressure. Mechanical force (pressure) is supplied by the mud pump—a push or pull which tends a system to change its state of rest or motion.

The relationship of physical properties of a drilling fluid in conjunction with a shear stress (pumping pressure) and a shear rate (velocity of the fluid or flow rate) is termed rheological behavior. Bits, pumps, flow rate and pump pressure, and drilling fluid rheological properties all relate to fluid hydraulics.

Drilling fluid design can minimize this effect. Full control needs optimization of drilling fluid hydraulics. As was noted, hydraulics uses pressure and volume produced by the mud pump. If we can focus the pressure and flow against the cutting structure of the bit, we can keep the cutting surfaces clean; in effect, we will be blasting these surfaces clean with high-pressure fluid flow.

The pressure in our system comes from the mud pump. We know that the pressure of the fluid at the pump is greater than the pressure of the fluid as the fluid exits the borehole.

So, if the pressure gauge at the pump is reading 500 psi and the pressure is effectively zero as the fluid exits the borehole, where did the pressure go? In its simplest form, the available pressure is lost due to overcoming the internal friction of the moving fluid, the friction of passing through the drill string and drill bit, and moving against the borehole walls.

Internally overcoming friction is really overcoming the resistance to flowing, which we have previously defined as viscosity. The total solids content of the drilling fluid (measured as density) and how these solids interact with each other (measured as plastic viscosity and yield point) are used in pressure loss calculations.

Inside our tubulars, turbulent flow can be expected due to pumping volume and rather small internal diameter. Luckily, drill steel will not be eroded by this turbulent flow.

The annulus is a much different environment. We do not want erosion of the borehole walls and we have added drilled cuttings to the drilling fluid that need to be transported to the surface. The magnitude of annular pressure loss is a function of type of flow, annular velocity, and mud properties, requiring laminar flow to maintain borehole wall integrity and effective cuttings transport. An uphole annular velocity of 60 to 120 feet per minute usually meets our requirements.

Rheology and hydraulics calculations provide the means for adjusting the drilling fluid’s properties, the flow rate, and bit nozzle size to optimize system pressure losses under the constraints imposed by the rig equipment.

Exploring this statement may answer some questions about pump type and bit design. The previous discussion would be primarily suited to positive displacement or piston pumps and drill bits that allow for adjusting the bit nozzle size.

Many of you drill with centrifugal pumps and use drill bits with no nozzles or open centers. Sure, you can drill with centrifugal pumps. They do allow for high flow rates, but they also lose efficiency with higher viscosity drilling fluids, have limited pressure limits, and lose efficiency with depth.

Centrifugal pumps do not work as well as positive displacement pumps when using jetted bits. Often the jets are too restrictive and too much pressure is lost at this point, so open center bits are preferred. Hole cleaning and cutting surface cleaning are accomplished by drilling fluid chemistry and flow volume. Hydraulics optimization is seldom used when drilling with centrifugal pumps.

Drag bits are very common in the water well business. Most of the designs have an open center and use flow volume to clean the cutting surface and move the drilled cuttings to the surface. I personally have never seen one with jets unless you consider a PDC bit a sophisticated drag bit.

You can create a “cutting” so large that it can’t be suspended or transported by the drilling fluid. It may be too large to even get past the side of the bit or fit in the annular space around drill collars or stabilizers. This causes packing off and restricts flow. Sometimes these sausages can’t be pumped out of the hole and must be pulled out by tripping out of the hole. In general, drag bits are not good candidates for hydraulics optimization.

The major goal of hydraulics optimization is to balance hole cleaning, pump pressure, and pressure drop across the bit. The drilling fluid’s density and rheological properties are the parameters that affect this hydraulic efficiency.

We looked at each part of the system, using the system approach to troubleshooting. We knew the geology was clay and a shale rock that easily got water wet and sticky. Mud system checked out for this geology. Piston pump for pressure and flow, poor flow coming out of the hole. Long-tooth bit should handle the formations. What’s missing?

We tripped the bit out of the hole and found it all balled up and mud and cuttings packed off around the stabilizer. It was obvious we were not cleaning the cuttings away from the bit teeth and insufficient flow to move them up into the flow stream and to the surface.

We didn’t use any math today at all. Know the geology. Formulate the proper drilling fluid and choose the best bit and pump with as much fluid pressure as you can. Put it to work for you.

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.

Progressive cavity pumps, also known as PC pumps, progressing cavity pumps, eccentric screw pump and mono pumps are a type of rotary positive displacement pump designed for the conveying of liquids and sludges from 1cst to 1Million. They handle not only viscous fluids and solids but also gassing or multiphase liquids containing gas slugs typical during crude oil extraction.

The volume of liquid pumped is proportional to speed providing a linear predictable pumping rate across a range of pressures. This technology delivers one of the highest flow and pressures available from a positive displacement pump being up to 600M³H and 48bar, with efficiency ranging from 55% to 75%. This technology is most suited for fluids more viscous than 5cst.

The design consists of a motor at the drive end which is connected to a gearbox as pc pumps operate at low rpm compared to centrifugal pumps. The output shaft from the gearbox connects to a rotor via a universal pin joint which rotates a metallic rotor within a rubber stator. Stators contain cavities, and the rotor pushes fluids through the cavities in a slow rotating fashion.

A pumps pressure generating ability will depend on the number of cavities within the pump, with high pressure designs often consisting of more than one stator and rotor. Each rotor will typically produce 6 bar enabling pressures up to 48 bar to be achieved through its modular design.

This design of pump is better suited for viscous lubricating fluids, which can contain solids. Short stator life can be experienced with abrasive slurries at which point a peristaltic pump can be a preferred option. Eccentric Screw Pumps viscosity handing is unrivalled, and they are usually specified when there are no other suitable options.

Stator designs consist of two types - equal and non-equal walled. Equal walled stators ensure a lower starting and running torque, lower pulsations and reduced power consumption, high volumetric pumping efficiency, and lower replacement costs. Materials are usually types of rubber being NBR, FKM but not PTFE meaning solvents cannot be handled.

·Oil & Gas – Cutting Transfer, Drilling Mud transfer and recovery, Separator Feed, Crude Oil Transfer, MOL (Main Oil line Pump), Multiphase transfer and injection in remote areas.

Low pulsating flow -Due to its rotary motion at low rpm, flow pulsation is limited with low amounts of acceleration head produced. Coupled with even wall design of stators and long pitch rotor design reduce pulsations further.

Low shear -Ensures gentle handling of the most difficult to pump fluids such as resins, viscous foods, oil and water emulsions without change in consistency to the liquid. They are often use in oily water separators as the design ensures oil droplets remain intact and was rated by SPE (Society of Petroleum Engineers) in Paper SPE18204 as the preferred pump to use for oil droplets which were disturbed the least during handling and a comparison of lobe, vane and screw technology.

Reversible – Units are reversible with reduced output pressure as standard meaning hoses can be emptied, or if blockages are encountered pump can be reversed to assist with clearing. It also enable the pump to be versatile for situations such as tanker loading and offloading.

Wide fluid handling capabilities –Designs can handle viscous liquids, large solids, abrasive materials, fibrous solids and gas slugs without issue making it one of the most versatile pumps available. This design has Unparalleled Viscosity handling viscosities from 1cst to 1Million means there are no comparable pumping technologies.

Self Priming –Due to the tight tolerances in its construction, it has high suction capabilities priming up to 8M, with a corresponding low NPSH. Designs are available which can withstand gas slugs for up to 30 minutes.

High Accuracy –Due to flow being directly proportional to pump speed, and due to its cavity design, it enables flows to be very predictable enabling it to be used in metering and dosing applications

Hopper Pump –A pump is fitted with a hopper of various designs, designed for viscous liquids, materials containing high amounts of dry matter, large solids requiring breaking up and materials which plasticise

Vertical Immersion –Designed to be immersed in the fluid such as in tanks eliminating NPSH issues, as units can be accepting of an NPSH as little as 0.5M (canned design) making them ideal for open or closed drain applications.

Multiphase Design -Baseplate mounted unit for multiphase boosting, with accessories allowing pump to handle viscous oil, gas slugs, sand and water, with automatic remote operation.

Bridge Breaker –For the breaking up of large solids within dehydrated sludge. Motorised paddles rotate within the hopper ensuring particles are broken into sizes which can be accommodated by the pump preventing blockages

Motorised wheel – Feeding of liquids with high dry solid content and materials which plasticize into the main pump. When materials such as liquid mortar, resins, mud, blocks of fat, or butter are pumped they can plasticise meaning they change shape rather than break up. To ensure they are fed into the rotor and stator, a motorised wheel ensures materials are broken up when other technologies may mean materials clog.

Liquid injection port –Typically used for the biogas sector, this unit has a separate injection port for accepting liquid manure which is combined with materials in the inlet containing high dry solids content (such as digestate, straw, corn, grass, rye, vegetable and food waste ) ensuring pumpability.

PC Pump curves are different to a centrifugal curve as it is linear demonstrating the units ability to handle liquids of varying viscosities with little impact on pump performance, with the bottom axis being speed rather than flow as flow is proportional to speed. Unit speed is much lower than centrifugal, operating from as little as 50rpm

Not suitable for solventsAll metal parts means solvents can be transferred, although some designs may have bearings within liquids and should be avoidedAll metal parts means solvents can be pumped.

Mud cleaning systems are critical in the drilling process, as they protect the system components by lowering the solids/sand content in the drilling fluid. Cleaner fluid means much longer expendable life in the entire mud cleaning and pumping system. Lower sand content also allows the drilling fluid to carry cuttings from the bore more efficiently, making for a better bore hole and a higher rate of penetration. In addition to helping alleviate environmental mud disposal concerns, reclaiming and recycling also allows for substantial mud cost savings.

There are three main types of systems — integral trailer, skid-mounted and trailer-mounted. Skid mounted allows for transporting through very swampy and difficult terrain, as you could drag it behind a dozer or excavator to your needed work area. Integral trailer designs allows for a more compact, intended design for maximum efficiency and ease of transport.

Any properly designed and sized mud system that is operated and maintained according to the manufacturers recommended procedures and maintenance schedules, should keep your sand content at or below ¼ of 1 percent. If you are not able to keep your sand content at or below ¼ of 1 percent, expendable life will greatly diminish along with the life span of system components and other items such as mud motors.

There are three main types of shaker motion available. Linear, orbital, and elliptical Linear motion shakers utilize a pair of eccentrically weighted, counter rotating vibrating motors. To date the linear motion shaker design is far superior, as it allows for a positive deck angle, which is the angle of adjustment of the shaker deck. Linear motion allows screened solids to travel uphill to the discharge end of the shaker bed. This allows you to keep liquids on the screens for a longer period while allowing a dryer cutting discharge. Both elliptical and orbital motion shakers do not allow for positive deck angles, and therefore require coarser screens to process fluids.

Screen type and mesh selection are crucial to fine tuning your mud system and allows for effective screening and longer screen life. Most manufacturers include a standard set of screens that are good for an all-around starting point. Keeping a good selection of assorted mesh screens is advised, as different soil conditions dictate different mesh. You want to run the finest mesh possible, without “blinding” the screens (plugging the screen openings with solids). Screens should be maintained during operations by rinsing periodically, and handled with care. They may be easily torn by rough or careless handling, or by having items dropped or set on them.

Most systems on the market have two or three compartment tanks, depending upon the number of cleaning stages. Proper tank design should allow fluid to overflow back to the previous cleaning stage tank in case of suspended out-flow from the system. Tank volume size should be properly matched to the systems overall cleaning volume capacities.

Ideally, the applicable mud system will utilize 5-in. desilter cones, which separate solids 15 to 25 microns in size, and 10-in. desander cones, which separate solids 40 to 50 microns in size. The size and quantity of cones needed on a system depend upon the overall rated volume of the mud system. The 5-in. cones can process 80 gpm each, and 10-in. cones can process 500 gpm each. There are other sizes of cones on the market, but we feel this gives us the best volume and micron size separation.

Centrifugal pumps that are driven by electric motors are responsible for moving the drilling fluids to various areas of the system within the cleaning process. Pumps and motors should both be sized correctly to adequately handle the systems volume needs. The centrifugal pumps may feature either mechanical seals or rope packing, depending upon the pump type. Mechanical seals are relatively maintenance free, but rope packing requires proper attention. Rope style packing allows some fluid “leakage” from the packing area. Do not tighten the packing housing down to stop the leaking completely, or seal and shaft damage will occur. You should always maintain a slow drip when using rope type packing.

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