2 replies to this topic

[ncarrascob]

Dear all,

I'm performing a project where Dry gas (after NGL separation)should be returned to the oil reservoir. For a given reservoir pressure, How higher Natural Gas Reinjection Pressure sould be?

thanks.

PD: It would be very useful to provide me some references

[Art Montemayor]

Neizer:

This is an easy response – but a detailed calculation work assignment.

What you haven’t stated and given is that you require a compression of the injection gas prior to it being returned to the reservoir and, as such, you have to specify what will be its discharge pressure. Am I correct in assuming your scope of work and basic data?

If so, then you have to calculate the flow resistance through ALL of the injection path that the gas will have to overcome. This is a pure Fluid Mechanics problem – but one involving a compressible fluid. So, it is not that simple. You must make a full and accurate survey of what all the resistances will be and make all the appropriate calculations. You normally would start your series of calculations starting at the downhole reservoir and work backwards to achieve the required compressor discharge pressure.

Depending on what kind of compressor you plan to employ, you should add the conventional additional contingency pressure to arrive at the specified design compressor discharge pressure.

Is that what you you are trying to find out? I don't know what you mean by "references", except to say that your engineering Fluid Mechanics courses and compressible flow calculations experience is what you require to do the job.

[ncarrascob]

Dear Art Montemayor

In fact, the scope of my work is what you have described clearly.
I just wanted to be sure that there is no faster way (yet reliable) to make this estimate.

Thank you very much for your help