7 replies to this topic

[blinx4real]

Hello all,
I am currently working on design of a water injection flowline and I need ideas on how to control the water flow to the individual wells. This is required because without control majority of the flow is diverted to one of the wells. There are three wells which we plan to inject. The wells are fed from a reciprocating pump.

The key challenge is that for safety reason we have been advised not to place a control valve downstream of the reciprocating pump. How else can the flow to the wells be controled?

Thanks

[ARAZA]

Hi There,

Consider a flow meter in the discharge line and cascade it with the speed controller of the PD pump.

Depending on the PD pump you choose, you can also set the flowrate by adjusting the stroke length of the piston.

ARAZA

[djack77494]

The key challenge is that for safety reason we have been advised not to place a control valve downstream of the reciprocating pump. How else can the flow to the wells be controled?

Splitting flows downstream of a reciprocating pump is quite a challenge indeed. I would not accept any convention control system for doing so - they won't work. Heck, you can't even measure flow downstream of a PD pump (I maintain this as fact despite claims to the contrary.) The simplest solution is to use three metering pumps to do this job. If you don't like this answer, I have found one type of self contained flow control valve that is designed to work in this type of application. It goes by the name of Sco-flow or something similar. My instrument engineer tells me that they have been successfully employed in reciprocating service.

[blinx4real]

Thank you all for the great ideas, I will further investigate your suggestions and see if they can be applied in this case. This is a very big issue that keeps cropping up time and time again, as my company uses a large number recip pumps.

[shan]

It is easy. If it is a new design, put a section of smaller size flowline to the high flow well. If it is an existed facility, replace the injection chokes of the high flow well with a smaller size choke.

[hollerg]

Depending on the head and flow requirements you might want to consider a rotojet pump. The design provides a stable flow as it is a centrifugal pump of a special configuration. It can easily accomodate a control valve control scheme although you must have a kickback to the source tank.

Gary

[djack77494]

I need ideas on how to control the water flow to the individual wells. This is required because without control majority of the flow is diverted to one of the wells. There are three wells which we plan to inject. The wells are fed from a reciprocating pump.

I forgot to mention in my earlier posting that you may use a multiplex metering pump. One motor and drive shaft with multiple heads. In function, it is the same as multiple metering pumps, but there could be cost savings, space savings, and reduced complexity going this route. Valve vendor refered to earlier is actually "SkoFlo".

[sheiko]

See

- API STD-674, Positive Displacement Pumps - Reciprocating.
- API STD-675, Positive Displacement Pumps - Controlled Volume.

Edited by Art Montemayor, 18 September 2009 - 08:42 AM.