Gas & Water Production

[Jriad]

Background: Shallow Gas well testing at 120 mcf/d & pulling a lot of water with it; 120 bbl/d. I am playing with the idea of downhole seperation and dumping the water in a lower zone (possibly a hydroclone) and see if it is economically viable.

Questions: Has anyone had experience with downhole seperation with gas and water?
Is there theoretical calculations to determine without the weight/resistance of lifting the water how much gas will be potentially produced?

Thanks,

JR

 

[zdas04]

If you do the separator calculations you'll find that it is really difficult to get substantial separation with equipment that will fit in a wellbore. For example, if I look at conventional vertical 2-phase separator on the surface my program wants a 36-in ID vessel. Probably bigger than your wellbore. The hydrocyclones can be configured to work with smaller vessels, but not as much smaller as the vendors would ask you to accept. The big problem is your 1,000 bbl/MMCF water production rate is really hard to get enough retention time to release the gas.

One idea that has worked is to set a packer below a pump (rod pump, PCP, ESP, whatever) and have the pump discharge below the packer. For cases where a disposal zone exists below the productive zone this can be effective where the regulators allow it. The lower zone will be a UIC well in the terminology of the U.S. EPA and their list of required data capture is not trivial and is very difficult to satisfy if you never bring the liquid to surface.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

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