Drilling Mud Pump Selection Tips, and a Notable Innovation

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.

You will get efficient and thoughtful service from HRSB.

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.

A Tribute to Innovations

Enter Cory Miller of Centerline Manufacturing, who I recently recommended for recognition by the National Ground Water Association (NGWA) for significant contributions to the industry.

The company is the world’s best w mud pump supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

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.

By Sharon Bueno

Mud recycling systems were once considered optional equipment. Environmental regulations continue to become more stringent and we must all responsibly make a contribution to protect our fragile ecosystem.

Using mud recyclers are a valuable asset to drilling contractors, as well-conditioned drilling fluid can save resources, time and money by reducing the amount of water and chemicals needed by reusing your bentonite and water. This helps maintain borehole stability with consistent mud properties through the entire circulation of the fluid and you haul off mainly the drilled solids, not the entire mud returns, including the liquid.

Drillers considering a mud recycler often ask: &#;Where do I start?&#; There are factors to consider before purchasing (or renting) a mud recycler, and, just like sizing the drill rig, sizing the recycler is equally important to your success. The following are some of the questions to ask yourself before making your purchase:

1. Type of drill rig will you be using?
2. Length of your average bore?
3. GPM of my mud pump or do I need a mud pump on the recycler?
4. Type and size of shakers on the unit?
5. Shaker screen sizes and availability, what is &#;mesh size&#;?
6. How do I know if the recycler is working?
7. Purpose of hydrocyclones, and how are they rated?
8. Do I need a trash pump?
9. Parts, service and warranty?

These factors are important to know so that you use a recycler that is sized to clean the mud and protect the components on the rig, pump and cleaner.

Drilling rigs are generally classified as &#;maxi,&#; &#;midsize&#; and &#;compact. While you can put a maxi recycler with a compact rig, it would not be advisable to do the reverse. Lesson: size accordingly.

Generally, longer bore holes require a larger pit volume in order to properly process the drill solids before sending the fluid back down hole.

As a general rule, size the recycler cleaning capacity to one and a half to two times the pumping volume (max gpm) of the triplex pump. HDD drillers normally run thicker fluids due to the low vertical height and long horizontal lengths of their bores; thicker fluid makes it more difficult for the shakers and cones to process (separate) the solids from the liquids. This is largely due to the natural coating ability of bentonite &#; It wants to encapsulate the solids and &#;hold on&#; to them. By upsizing the recycler, the solid particles have a second or third opportunity to process through the mud recycler for removal before going back to the rig.

Example: If you are pumping 200 gpm, you would need a 350- to 400-gpm recycler.

Some mud recyclers provide an &#;onboard&#; mud pump that was sized specifically to the recycler. This enables the driller to use all available drill rig horsepower toward the rotation and push-pull of the drill pipe, thereby not &#;robbing&#; it for an onboard triplex pump.

Most recyclers today use orbital, elliptical or linear motion shakers, and each has a place in different drilling scenarios. With that being said, linear motion shakers generate high G-Forces and are especially effective in shallow formation sections where high-volume, heavy solids are encountered, and have the ability to remove the solids quickly.

When choosing a linear shaker for your mud system, look for a long runway (area of length from the front of the shaker to the end where the cuttings dump off). The longer length shaker bed allows extra time for solids to separate from the liquid, and result in drier solids leaving the mud system for disposal. You can also increase the angle of the shaker bed by five degrees to further increase the travel time of the solids.

Proper shaker screen selection enhances the results of the mud recycler, and, combined with the G-Force of the shaker, works in tandem to maximize solids dryness. In the past, shaker screens were sized by mesh size.



Example: 40 mesh screen had 40 openings per square inch of screen area. As a measurement, this left room for a lot of unknown variables, including questioning what gauge wire was used in the manufacture of the screens. The wire gauge altered the size of openings on the screen surface and resulted in changing the size of the solids that the screen could pass or &#;cut.&#;

The industry needed a consistent way to measure the &#;cut point&#; of the screens, and the API introduced the D100 designation, or D100 &#;cut point&#; using the average micron cut of the shaker screen, depending on the wire. Two examples are the CRX Oblong and UF square meshes.

Identification of particle sizes from core samples taken on each drilling location provides drillers valuable information and aids in selecting screens. Drilling contractors should carry a couple of testing tools to measure the effectiveness of a of the mud recycler while drilling. These tools are: a Marsh funnel and cup, sand content kit and mud weight scales. Taking mud samples from the return pit or possum belly before the mud is processed, the underflow and overflow of the cones and the clean mud tank help monitor the effectiveness of each component of the recycler, and the driller can make component adjustments to achieve maximum efficiency.

In addition to the shale shakers, another way to size the processing capability of the mud recycler is to look at the hydrocyclone. Depending on the size of the mud recycling system, cone size will be 4, 5, 10 or 12 in. Each size cone has a micron &#;cut point,&#; and represents the size of the smallest particle the cone can &#;pull.&#; Four- and 5-in. cones have a 20-micron &#;cut point,&#; and 10- and 12-in. cones have a 74-micron &#;cut point.&#; Smaller mud systems normally have two section tanks, with a &#;dirty&#; tank under the scalping shaker and a &#;clean&#; tank under the mud cleaner (shaker with desilting cones), while larger systems can have three section tanks with scalping, desanding and desilting.

One hydrocyclone processes liquid at a rate of 50 gpm/ 4-in. cone, 80 gpm/ 5-in. cone, and 500 gpm/ 10-in. or 12-in. cone. Some manufacturers&#; volume amount for their respective cone sizes may differ than those cited herein, but these are the most common within the industry for reference purposes.

Maintaining proper pressure is essential for the hydrocyclones to work effectively, with the normal operating pressure range for 4- and 5-in. cones of 30 to 40 psi; 10- and 12-in. cones of 23 to 35 psi. Pressure above 45 to 50 psi cause premature internal cone wear, and lower pressure down around 20 to 22 psi is a &#;red flag&#; that you better consider rebuilding the centrifugal(s) to maintain pressure in the optimum range.

Borehole returns require transport into the recycler via a &#;trash&#; pump properly sized for the job. Different pumps are available, but the three most common are: 1) submersible, 2) semi-submersible, and 3) aboveground centrifugal with a foot valve. Totally submersible pumps are generally the smallest in size, have a flooded suction to help in priming, and though the most convenient option, are usually the most expensive. Semi-submersible trash pumps still have a flooded suction, but the drive motor is not submerged into the fluid. Semi-submersible pumps work well, but are heavier, and longer than the submersible pumps.  Another option is an above ground centrifugal pump with a foot valve, and once primed, is dependable and normally used on larger recyclers for their increased volume capacities.

If your drilling crew has never operated a mud recycler, be sure that you are provided with training and try renting a unit to make sure it is the right &#;fit&#; prior to purchase. Be familiar with the maintenance requirements of your mud system; usually the owner&#;s manual is sufficient, but inquire if the manufacturer offers training videos, onsite or plant training sessions and &#; the most important &#; technical support.

A manufacturer should stand behind the equipment its builds so don&#;t settle for a warranty less than one year. Ask questions about the warranty prior to finalizing the purchase.

In an age where protection of our planet is a major concern, so should your choice of mud systems. Choose a recycler that is respectful to the environment and leaves your jobsite as clean as possible.  Do your research, talk to other drillers, decide what you need and you will be able to make the best decision for you and your company.

John Miller is CEO of Mud Technology International Inc., Athens, Texas.

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Mud recycling systems were once considered optional equipment. Environmental regulations continue to become more stringent and we must all responsibly make a contribution to protect our fragile ecosystem.Using mud recyclers are a valuable asset to drilling contractors, as well-conditioned drilling fluid can save resources, time and money by reducing the amount of water and chemicals needed by reusing your bentonite and water. This helps maintain borehole stability with consistent mud properties through the entire circulation of the fluid and you haul off mainly the drilled solids, not the entire mud returns, including the liquid.Drillers considering a mud recycler often ask: &#;Where do I start?&#; There are factors to consider before purchasing (or renting) a mud recycler, and, just like sizing the drill rig, sizing the recycler is equally important to your success. The following are some of the questions to ask yourself before making your purchase:1. Type of drill rig will you be using?2. Length of your average bore?3. GPM of my mud pump or do I need a mud pump on the recycler?4. Type and size of shakers on the unit?5. Shaker screen sizes and availability, what is &#;mesh size&#;?6. How do I know if the recycler is working?7. Purpose of hydrocyclones, and how are they rated?8. Do I need a trash pump?9. Parts, service and warranty?These factors are important to know so that you use a recycler that is sized to clean the mud and protect the components on the rig, pump and cleaner.Drilling rigs are generally classified as &#;maxi,&#; &#;midsize&#; and &#;compact. While you can put a maxi recycler with a compact rig, it would not be advisable to do the reverse. Lesson: size accordingly.Generally, longer bore holes require a larger pit volume in order to properly process the drill solids before sending the fluid back down hole.As a general rule, size the recycler cleaning capacity to one and a half to two times the pumping volume (max gpm) of the triplex pump. HDD drillers normally run thicker fluids due to the low vertical height and long horizontal lengths of their bores; thicker fluid makes it more difficult for the shakers and cones to process (separate) the solids from the liquids. This is largely due to the natural coating ability of bentonite &#; It wants to encapsulate the solids and &#;hold on&#; to them. By upsizing the recycler, the solid particles have a second or third opportunity to process through the mud recycler for removal before going back to the rig.Example: If you are pumping 200 gpm, you would need a 350- to 400-gpm recycler.Some mud recyclers provide an &#;onboard&#; mud pump that was sized specifically to the recycler. This enables the driller to use all available drill rig horsepower toward the rotation and push-pull of the drill pipe, thereby not &#;robbing&#; it for an onboard triplex pump.Most recyclers today use orbital, elliptical or linear motion shakers, and each has a place in different drilling scenarios. With that being said, linear motion shakers generate high G-Forces and are especially effective in shallow formation sections where high-volume, heavy solids are encountered, and have the ability to remove the solids quickly.When choosing a linear shaker for your mud system, look for a long runway (area of length from the front of the shaker to the end where the cuttings dump off). The longer length shaker bed allows extra time for solids to separate from the liquid, and result in drier solids leaving the mud system for disposal. You can also increase the angle of the shaker bed by five degrees to further increase the travel time of the solids.Proper shaker screen selection enhances the results of the mud recycler, and, combined with the G-Force of the shaker, works in tandem to maximize solids dryness. In the past, shaker screens were sized by mesh size.Example: 40 mesh screen had 40 openings per square inch of screen area. As a measurement, this left room for a lot of unknown variables, including questioning what gauge wire was used in the manufacture of the screens. The wire gauge altered the size of openings on the screen surface and resulted in changing the size of the solids that the screen could pass or &#;cut.&#;The industry needed a consistent way to measure the &#;cut point&#; of the screens, and the API introduced the D100 designation, or D100 &#;cut point&#; using the average micron cut of the shaker screen, depending on the wire. Two examples are the CRX Oblong and UF square meshes.Identification of particle sizes from core samples taken on each drilling location provides drillers valuable information and aids in selecting screens. Drilling contractors should carry a couple of testing tools to measure the effectiveness of a of the mud recycler while drilling. These tools are: a Marsh funnel and cup, sand content kit and mud weight scales. Taking mud samples from the return pit or possum belly before the mud is processed, the underflow and overflow of the cones and the clean mud tank help monitor the effectiveness of each component of the recycler, and the driller can make component adjustments to achieve maximum efficiency.In addition to the shale shakers, another way to size the processing capability of the mud recycler is to look at the hydrocyclone. Depending on the size of the mud recycling system, cone size will be 4, 5, 10 or 12 in. Each size cone has a micron &#;cut point,&#; and represents the size of the smallest particle the cone can &#;pull.&#; Four- and 5-in. cones have a 20-micron &#;cut point,&#; and 10- and 12-in. cones have a 74-micron &#;cut point.&#; Smaller mud systems normally have two section tanks, with a &#;dirty&#; tank under the scalping shaker and a &#;clean&#; tank under the mud cleaner (shaker with desilting cones), while larger systems can have three section tanks with scalping, desanding and desilting.One hydrocyclone processes liquid at a rate of 50 gpm/ 4-in. cone, 80 gpm/ 5-in. cone, and 500 gpm/ 10-in. or 12-in. cone. Some manufacturers&#; volume amount for their respective cone sizes may differ than those cited herein, but these are the most common within the industry for reference purposes.Maintaining proper pressure is essential for the hydrocyclones to work effectively, with the normal operating pressure range for 4- and 5-in. cones of 30 to 40 psi; 10- and 12-in. cones of 23 to 35 psi. Pressure above 45 to 50 psi cause premature internal cone wear, and lower pressure down around 20 to 22 psi is a &#;red flag&#; that you better consider rebuilding the centrifugal(s) to maintain pressure in the optimum range.Borehole returns require transport into the recycler via a &#;trash&#; pump properly sized for the job. Different pumps are available, but the three most common are: 1) submersible, 2) semi-submersible, and 3) aboveground centrifugal with a foot valve. Totally submersible pumps are generally the smallest in size, have a flooded suction to help in priming, and though the most convenient option, are usually the most expensive. Semi-submersible trash pumps still have a flooded suction, but the drive motor is not submerged into the fluid. Semi-submersible pumps work well, but are heavier, and longer than the submersible pumps. Another option is an above ground centrifugal pump with a foot valve, and once primed, is dependable and normally used on larger recyclers for their increased volume capacities.If your drilling crew has never operated a mud recycler, be sure that you are provided with training and try renting a unit to make sure it is the right &#;fit&#; prior to purchase. Be familiar with the maintenance requirements of your mud system; usually the owner&#;s manual is sufficient, but inquire if the manufacturer offers training videos, onsite or plant training sessions and &#; the most important &#; technical support.A manufacturer should stand behind the equipment its builds so don&#;t settle for a warranty less than one year. Ask questions about the warranty prior to finalizing the purchase.In an age where protection of our planet is a major concern, so should your choice of mud systems. Choose a recycler that is respectful to the environment and leaves your jobsite as clean as possible. Do your research, talk to other drillers, decide what you need and you will be able to make the best decision for you and your company.

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