Pump design requirements in Drilling

[JonnyWill]

Pump design requirements in Drilling.
The pumps in the drilling industry are missing check valves on the outlet from the centrifugal & reciprocating pumps; Why are there no check valves in the drilling process? Are not Mud & check valves a good combination?

Additionally what are the filter requirements around pumps which are pumping mud? It is suggested that duplex filters are required. These pumps are pumping mud not hydraulic or lubrication fluid which then I would insist on duplex filters. The pumps in question are stopped & started at irregular intervals. Are Duplex filters necessary and when would one install Duplex filters?

Is there an industry norm which I can use for the basis of the design around pumps? Any feedback information would be beneficial.
Cheers

 

[BigInch]

Since they pump fluid down into a hole, the potential for excessive backflow is limited.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[JonnyWill]

But you are forgetting the prime function of a check valve is to protect mechanical equipment; pumps, strainers, flowmeters, control valves etc in a piping system by preventing reversal of flow by the fluid. This is particularly important in the case of rotating equipment, where back flow could damage the internals of the equipment and cause an unnecessary shutdown of the system.

 

[BigInch]

I didn't forget that. But, if what you say were 100% true, ALL pumps would have check valves built in wouldn't they. Centrifugals can be run in reverse, but not if backflow is limited.

Since the purpose of mud is to balance the geologic pressure plus the weight of the column of cutting fluid moving up to the surface, when the pump stops, pressure at the discharge quickly falls. Its not like you're pumping up a 1000 foot high hill to the bottom of a reservoir, where it could be pretty smart to install a check valve.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Artisi]

Are you trying to design a pump or are you asking about the application of mud pumps well drilling?

 

[JonnyWill]

Artsi: the query is about pumps in the drilling system in general; no I’m looking at the design of the mud system. Is there a requirement to have a check valves after pumps when pumping mud? And as these pumps tend to be intermittent is there a requirement to have duplex filters?
Biginch: Pumping to head height of 35ft before it goes into the drill string. If the drilling stops there will be 35ft of mud in a 5” pipe on the mudpumps. As for the other pumps that’s a different subject.

 

[BigInch]

Probably less than 20 psi. Will that even turn a drilling pump backwards?

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[micalbrch]

JonnyWill,

Reciprocating pumps like piston and/or plunger pumps have an inbuilt check valve on the outlet of each piston/plunger chamber - unless they are simplex single acting. But I have never seen such a pump without suction and discharge side check valve.

regards

Micalbrch

 

[JonnyWill]

Micalbrch:- I agree, I am use to seeing a Check valve mainly on the discharge side of pumps; but in Drilling there aren't any! Hence the Thread. I'm aware of the in-build check valve on some recips but in certain process conditions there is sometimes an additional outside the pump package for safe measure.
Big Inch: My mistake height clearance is 55metres. Point taken regarding the HP pump but again there are other pumps; Centrifs with no check valve!
Again in normal process conditions Check valves are placed on the discharge side of the pumps, why is this not the case for drilling?

 

[BigInch]

Simple. A check valve just isn't needed for process systems, unless significant backflow is possible. In a lot of process systems where fluids are not very compressible and pressurized volumes are relatively low, large decreases in discharge pressure occur as soon as only a very small amount of fluid backflows into the pump. Without high static heads downstream to maintain the flow, its very often not a problem to worry about too much. Long pipelines with large volumes at high pressure in the discharge piping, possibly with high static heads as well, that could sustain backflows for longer periods could easily warrant placement of a discharge check valve. In fact it is sometimes difficult to start a low torque pump against high heads, so a check valve is included for starting purposes as well as it might be included for backflow control. It really just depends on what kind of system you have and what the system response is to a pump shutdown, how fast the pump breaks speed and reverses. If its a relatively high inertia pump, its slow and no significant stresses result. On the other hand a relatively low inertia pump may be a different story. You don't always need one, so the pumps don't come with them already in the box.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Artisi]

As stated by BigInch seems there is no need also as it is drilling mud containing lots of "grit"from the drilling process it is unlikely that check valves would be of any use anyway.

As for your question of duplex filters - what are you trying to achieve - filter the grit from the mud? pump the mud to a settling tank or pond and let most of the grit seperate there or put the return mud thru a hydro-cyclone. I would think duplex filters would cause a major problem - and choke off in a matter of no time at all.