mud pump charging system free sample

The Charge Free Dampening System™ combines the advanced technologies of Sigma’s Charge Free Dampeners™, Sigma’s Charge Free Conversion Kits®, Sigma’s Charge Free Stabilizer™, and Sigma’s Acoustic Assassin® to create the best available pulsation control solution. When it comes to performance and cost, Sigma’s Charge Free Dampening System™ will out perform more expensive dampeners while significantly reducing weight, size, and cost.

The Charge Free Stabilizer™ was designed to be installed directly before the suction manifold port between the mud pump and the charge pump. Maximizing mud pump performance by eliminating cavitation while isolating both the mud and charge pumps.

The Acoustic Assassin® was designed to be installed between the pump loop manifold and the production line. This fixture is a multi-chambered baffling system that will reduce damaging acoustic resonance generated by reciprocating pumps. The Acoustic Assassin® is an ideal addition to any pulsation control system.

The Charge Free Conversion Kit® is a high performance pulsation control kit that utilizes both compression and kinetic exchange for superior performance over traditional pulsation control methods of the past. With a gigantic increase in surface area, compression tuning, and a design to maximize energy exchange, the CFC Kits control pulsations from the pump while cleaning the signal for MWD tools.

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 gas over fluid internal systems has limitations too. The standpipe loses compression due to gas being consumed by the drilling fluid. In the absence of gas, the standpipe becomes virtually defunct because gravity (14.7 psi) is the only force driving the cylinders’ fluid. Also, gas is rarely replenished or charged in the standpipe.

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.

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.

Although cavitation is avoidable, without proper inspection of the feed system, it can accelerate the wear of fluid end parts. Over time, cavitation can also lead to expensive maintenance issues and a potentially catastrophic failure.

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.

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.

Accelerometers can also be used to detect slight changes in module performance and can be an effective early warning system for cavitation prevention.

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.

It may be impractical to flush system piping during drilling operations. However, strainer screens should be checked daily to remove any debris or other flow restrictions.

This invention relates to apparatus useful in connection with the drilling of wells, such as oil wells, wherein a mud pump is used to circulate drilling mud under pressure through a drill string, down to and around the drill bit and out the annulus of the bore hole of the well to a mud reservoir; the apparatus of the present invention being useful for simultaneously degassing drilling mud and supercharging the mud pump.

In the drilling of deep wells, such as oil wells, it is common practice to penetrate the earth with a drill bit supported on a drill string in the bore of the well being drilled. In order to lubricate the drill bit, protect the well against blowouts, etc., it is conventional practice to circulate mud under pressure through the drill string down to and around the drill bit and up the annulus between the drill string and the bore of the well. Mud flowing from the well is passed through a suitable device such as a shaker, etc., in order to remove drill cuttings, etc., and is then delivered to a mud reservoir, such as a mud tank, for recirculation to the mud pump for pressured injection into the well.

It is also conventional practice to use a mud pump, such as a duplex or triplex mud pump comprising reciprocating pistons mounted in cylinders for pressuring the incoming drilling mud and delivering it to the well bore under pressure. The operation and construction of mud pumps is well known to those of ordinary skill in the art, as illustrated, for example, by the textbook "Mud Pump Handbook" by Samuel L. Collier (Gulf Publishing Company, Houston, Tex., 1983).

It is known, as explained in the Collier handbook, that the efficiency of a mud pump can be significantly improved by supercharging the pump; that is, by delivering drilling mud under pressure to the mud pump inlet to the cylinders containing the reciprocating pumping pistons.

It is also known to remove occluded gasses such as air, methane, etc., from drilling mud before it is delivered to the mud pump as illustrated, for example, by Burgess U.S. Pat. No. 3,973,930, Burgess U.S. Pat. No. 3,999,965 and Burgess U.S. Pat. No. 4,084,946.

Other drilling mud degassing devices are known to the art, such as those disclosed in Phillips et al. U.S. Pat. No. 4,088,457, Brown et al. U.S. Pat. No. 4,113,452, Egbert U.S. Pat. No. 4,365,977, Gowan et al. U.S. Pat. No. 4,397,659, etc.

Mud pumps used for delivering drilling mud under pressure to the bore hole of a well are conventionally of the type wherein a reciprocating piston in a cylinder is used to pressure drilling mud delivered to the cylinder for delivery to the well bore. Normally, two or three such cylinders are used, such pumps being conventionally referred to as duplex and triplex pumps. During each stroke of the piston, the piston is initially accelerated by an appropriate drive means, such as a crank shaft, from a starting position to a midcylinder position, and then decelerated to a final position within the cylinder. This constantly changing rate of motion of a reciprocating piston can result in knocking, cavitation, etc., all of which impair the efficiency of the pump. It is known to use centrifugal pumps, commonly known as superchargers, in order to deliver drilling mud to the inlet of the cylinder under pressure in order to alleviate such problems and improve the efficiency of operation of the pump.

It is undesirable to recirculate drilling mud containing occluded gases to a well bore, and therefore it is common practice to remove a significant portion of occluded gas from the drilling mud before it is recirculated to the mud pump. Normally, separate pieces of equipment that operate independently of each other are used for supercharging the mud pump and for degassing the drilling mud.

It has been discovered in accordance with the present invention that a drilling mud degasser of the type disclosed in the Burgess patents can be modified to simultaneously degas drilling mud and to supercharge the mud pump to which the degassed mud is to be delivered.

This is accomplished in accordance with the present invention through the provision of a device for simultaneously supercharging a mud pump having pistons reciprocably mounted in cylinders while degassing drilling mud to be delivered to said pistons comprising:

vacuum chamber means for continuously accelerating and centrifuging drilling mud under vacuum to thereby substantially completely remove occluded gas from the drilling mud,

a first conduit interconnecting said vacuum chamber with a drilling mud reservoir for delivering drilling mud to be degassed to said vacuum chamber means,

a first valve controlled branch conduit interconnecting said second conduit with said drilling mud reservoir for delivering drilling mud to said drilling mud reservoir when the pressure in said second conduit exceeds a predetermined value, and

a second branch conduit containing normally closed flow control means interconnecting said second conduit with said first conduit and said drilling mud reservoir operable on loss of pressure in said second conduit to permit flow of drilling mud directly from said drilling mud reservoir to said second conduit.

Referring now to the drawing, there is shown a supercharging drilling mud degasser 10 of the present invention which comprises a degassing chamber designated generally by the number 12, a power source such as an electric powered motor or a hydraulically powered motor designated generally by the number 14, a vacuum blower such as a regenerative vacuum blower, designated generally by the number 16, a gear box designated generally by the number 18, an evacuation pump designated generally by the number 20 and a drilling mud chamber designated generally by the number 22.

In accordance with this construction, there is provided a drilling mud degasser of the type shown in Burgess U.S. Pat. No. 4,084,946, housed in a cylindrical pressure vessel 24. The motor 14 is supported on vacuum blower 16 which, in turn, is supported by vacuum motor support 26 and vacuum blower brackets 28. To facilitate movement of the degasser 10, motor handling brackets 30 may be provided on the top of the motor 14 to which the hook of a crane or other appropriate means (not shown) may be attached.

Drilling mud pump impeller 42 is fixed to the centrifuge tube 40 for rotation therewith within the housing 46 of drilling mud evacuation pump 20. Cross braces 48 mounted in the cylindrical vessel 24 support lower stops 50 and upper stops 52 for an annular float 56 that surrounds the slots of the centrifuge tube 40 and partially closes them, such that the free area of the slots will be determined by the relative position of the annular float 56.

A drilling mud inlet 60 is connected to the bottom of the housing 46 for the evacuation pump 20 for the delivery of degassed drilling mud thereto. Drilling mud is delivered to the slotted centrifuge tube 40 by an inlet conduit 62 which preferably terminates inside the housing 46 for the evacuation pump 20. The top of the inlet line 62 is spaced from the bottom of the slotted centrifuge tube 40 so that the rotating centrifuge tube 40 can rotate freely without bearing upon the top of the inlet line 62. The resultant "controlled seepage" of fluid from the inlet tube 62 into the evacuation pump 20 provides a low pressure area for high effeciency scanvenging of occluded gases. Also, there is no need for bearings and seals at the bottom of the slotted centrifuge tube 40.

With this construction there is also provided an outlet line or conduit 66 connected with the discharge side of the evacuation pump 20 and extending through the wall of the cylinder 24 for connection with a suitable first conduit 68 leading, for example, to a triplex pump 70 for injecting drilling mud under pressure into a well penetrating a subterranean formation in order to lubricate the drill bit, protect the well against blow outs, etc., it is conventional practice to circulate mud under pressure through the drill string down to and around the drill bit and up the annulus beteen the drill string and the bore of the well. Mud flowing from the well is passed through a suitable device such as a shaker, etc. (not shown) in order to remove drill cuttings, etc., and is then delivered to a mud reservoir, such as a mud tank 84, for recirculation to the mud pump 70 in the manner described herein for pressured injection into the well.

The first conduit 68 may comprise, for example, a connecting pipe 72 interconnecting the outlet line 66 with the flexible hose 74 which, in turn, is connected to a mud pump inlet line 76. The flexible hose 74, which is provided for ease in alignment, may be secured to the connecting pipe 72 by a clamp 78 of any suitable construction and to the mud pump inlet line 76 by a clamp 80 of any suitable construction.

A second conduit 82 interconnects a drilling mud reservoir such as a mud tank 84 with the inlet conduit 62 leading to the slotted centrifuge tube 40 for the degasser 10.

Preferably, the second conduit 82 is provided with valve means such as a butterfly valve 86 which may be used to close the second conduit 82 when both the drilling mud degasser 10 and the mud pump 70 are to be idled for any appreciable time.

A first branch conduit 88 interconnects the first conduit 68 with the mud tank 84 and contains pressure sensitive control means such as a spring biased relief valve 90 in order to permit drilling mud to recycle from the first conduit 68 to the mud tank 84 when the pressure in the first conduit 68 exceeds a predetermined value.

A second branch conduit 92 interconnects the first conduit 68 with the inlet conduit 62 and the second conduit 82. The second branch conduit 92 contains normally closed flow control means such as a check valve 94 to permit flow of drilling mud directly from the mud tank 84 to the mud pump 70 if the pressure in the first conduit 68 falls below a predetermined value.

During drilling operations, rotation of an appropriate vacuum blower such as a regenerative vacuum blower by the drive shaft 32 for the motor 14 will generate a vacuum in the degassing chamber 12 such that drilling mud sprayed from the slots in the centrifuge tube 40 will tend to impact upon the inner sides of the degassing chamber 12 thereby initiating degassing of the drilling mud fed through the inlet line 62. Rotation of the centrifuge tube 40 will impart upward accelerating rotary motion to partially degassed drilling mud delivered thereto through the line 62 and the resultant spraying of the thus centrifuged drilling mud through the slots in the centrifuge tube 40 will result in a sheet of drilling mud being sprayed onto and impacting on the inner walls of the degassing chamber 12 to thus substantially complete the removal of gas from the drilling mud. The thus degassed drilling mud will flow downwardly past cross braces 48 and into inlet 60 leading through the housing 46 of the evacuation pump 20 where the impeller 42 will repressure the now degassed drilling mud for discharge through the outlet line 66 which is interconnected with a triplex pump 70 by first conduit 68 for supercharging the pump 70, which further pressures the degassed drilling mud for injection into a well bore penetrating a subterranean formation.

In order to prevent the entrainment of drilling mud droplets in the gases withdrawn through the gas evacuation suction pipe 98, a splatter plate 100 is provided in the degassing chamber 12 and a combination of a foam separation impeller 36 with a splatter disk 102 is provided adjacent the top of the degassing chamber 12 so that gas liberated in the vacuum chamber must follow a sinuous path arriving at the upper chamber gas evacuation suction pipe 98.

In accordance with the present invention, the motor 14 is operated such that drilling mud delivered to the first conduit 68 will be at a predetermined appropriate supercharging pressure for the mud pump 70, (e.g. a pressure of about 20 to 30 psig).

The pressure sensitive control means, such as a spring biased relief valve 90, is set to open at a predetermined pressure about 5 to 10 psi higher than the desired pressure in the first conduit 68 so that, if the indicated pressure limit is exceeded, the pressure relief valve 90 will open in order to permit drilling mud to recycle to the mud tank 84.

This will happen if the mud pump 70 malfunctions and also when the mud pump 70 is turned off, as will happen from time to time. For example, it is necessary to turn off the mud pump 70 during drilling operations when a new stand of drill pipe is to be added to the drill string. It is also necessary to turn off the mud pump 70 when the drill string is being withdrawn from the well bore in order to replace the drill bit, while well logging operations are in progress, if it is necessary to "fish" for a piece of equipment lost down the hole, etc. However, if the drilling mud in the mud tank 84 is permitted to remain quiescent for more than a limited period of time, the drilling mud may start to gel and/or to stratify. This problem is conventionally avoided by providing a separate agitator (not shown) for the mud tank 84 in order to stir the drilling mud when the mud pump 70 is idle. However, through the provision of the present invention, there is no need for a separate agitator for the mud tank 84 because recirculation of drilling mud through the first branch conduit 88 will impart a "roiling" motion or agitation to the drilling mud in mud tank 84 to inhibit gelling and/or stratification of the drilling mud while the mud pump 70 is idle.

Loss of pressure in the first conduit 68 can occur in the event of malfunction of the degasser 10 or in the event it is desired to shut the degasser 10 down for a limited period of time. In this event, drilling mud flows directly from the mud tank 84 through the second conduit 82, the second branch conduit 92 and the flexible hose 74 to the mud pump 70 so that the mud pum 70 is not "starved" for drilling mud to be injected into the well.

OK, all y’all air drillers just thumb on over to Porky’s column or something. This is for mud drillers. On second thought, I know a lot of you air guys drill about three mud wells a year, and consider it a hassle to rig up mud. So, maybe something I say will be interesting …

The mud pump is the heart of the circulating system, and mud is the blood circulating in the hole. I’ve talked about mud before and will again, but this month, let’s talk about the pump.

Historically, more wells, of every kind, have been drilled with duplex pumps than any other kind. They are simple and strong, and were designed in the days when things were meant to last. Most water well drillers use them. The drawbacks are size and weight. A pump big enough to do the job might be too big to fit on the rig, so some guys use skid-mounted pumps. They also take a fair amount of horsepower. If you were to break down the horsepower requirements of your rig, you would find out that the pump takes more power than the rotary and hoist combined. This is not a bad thing, since it does a lot of the work drilling. While duplex pumps generally make plenty of volume, one of the limiting factors is pressure. Handling the high pressures demanded by today’s oil well drilling required a pump so big and heavy as to be impractical. Some pretty smart guys came up with the triplex pump. It will pump the same — or more — volume in a smaller package, is easy to work on and will make insane pressure when needed. Some of the modern frack outfits run pumps that will pump all day long at 15,000 psi. Scary. Talk about burning some diesel.

The places that triplex pumps have in the shallow drilling market are in coring and air drilling. The volume needs are not as great. For instance, in hard rock coring, surface returns are not always even seen, and the fluid just keeps the diamonds cool. In air drilling, a small triplex is used to inject foam or other chemicals into the air line. It’s basically a glorified car wash pump. The generic name is Bean pump, but I think this just justifies a higher price. Kinda like getting the same burger at McDonald’s versus in a casino.

One of the reasons water well drillers don’t run triplex pumps, besides not needing insane pressure, is they require a positive suction head. In other words, they will not pick up out of the pit like a duplex. They require a centrifugal charging pump to feed them, and that is just another piece of equipment to haul and maintain.

This brings me to another thought: charging. I know a lot of drillers running duplex pumps that want to improve the efficiency of their pumps. Duplexes with a negative suction head generally run at about 85 percent efficiency. The easy way to improve the efficiency is to charge them, thus assuring a 100 percent efficiency. This works great, but almost every one of them, after doing all that work and rigging up a charging pump, tells me that their pump output doubled. Being the quiet, mild mannered type that I am, I don’t say “Bull,” but it is. A duplex pump is a positive displacement pump. That means that it can deliver no more than the displacement it was designed for. You can only fill the cylinder up until it is full. It won’t take any more. The one exception to this is when you are pumping at very low pressure. Then the charging pump will over run the duplex, float the valves and produce a lot more fluid. Might as well shut off the duplex and drill with the charging pump.

Another common pump used in the water well industry is the centrifugal. You see them mostly on air rigs that don’t use mud too often. They have their place, but are a different breed of cat. They are not positive displacement. Flow is a function of speed and horsepower up to the limits of the pump. After that, they just dead-head. With large diameter drill pipe they make a lot of mud, but after the hole gets deeper, friction losses — both inside and outside the drill pipe — build up. This means that the deeper you go, the less circulation you have. This slows the whole process. Positive displacement pumps don’t do this; they pump the same per stroke regardless of pressure. It just takes more horsepower. Also, displacement calculations like bottoms-up time and cement placement are just about impossible. One way to get around the limited pressure of centrifugal pumps is to run two of them in series. I’ve seen a few of these rig-ups and they work very well for large diameter drilling. They will make almost the same pressure as a big duplex for a lot less money. They are still variable displacement, but they roll so much fluid that it doesn’t seem to matter. And run at pretty reasonable depths, too: 300 to 400 psi at 400 gpm is not uncommon with two 3 x 4 centrifugal pumps in series.

I reckon there are pumps for every type of drilling. It is just a matter of using the right one correctly. I once drilled a 42-inch hole 842 feet deep with a 5½ x 8 duplex. Talk about long bottoms-up time … but we got the casing in with less than two feet of fill on bottom! Took time, but we got-er-done.