Annulus gas rate
Annulus gas rate
(OP)
thread469-189800: Annulus Gas Pressure
Assuming that besides reducing back pressure on the formation you also want to use the annulus gas to fuel a gas engine as your pumping unit prime mover, does anybody know a "low tech" wellsite test to determine the gas daily flow rate? I mean, something without orifice plates or flowmeters, and similar to the "Bucket Test" we use to estimate oil production.
Assuming that besides reducing back pressure on the formation you also want to use the annulus gas to fuel a gas engine as your pumping unit prime mover, does anybody know a "low tech" wellsite test to determine the gas daily flow rate? I mean, something without orifice plates or flowmeters, and similar to the "Bucket Test" we use to estimate oil production.





RE: Annulus gas rate
I suppose you can put a recording gauge upstream of a valve, start it recording and open the valve to atmosphere. Until the pressure is around 15 psig the flow will be choked and you can figure volume flow rate from the sonic velocity at each pressure and the area of the exit pipe.
David
RE: Annulus gas rate
RE: Annulus gas rate
RE: Annulus gas rate
RE: Annulus gas rate
Your fundamental problem is one that has existed in pumped wells for decades. The gas flow in the annulus is dominated by the liquid level above the pump, so any pre-pumping gas-flow test you run will not accurately represent the gas available. The nearly universal solution is to set a propane tank to pump the well down some and then try the annular gas. If there is enough then you can redeploy the propane tank. If there isn't enough then you have to decide if the well can tolerate the cost of propane.
David
RE: Annulus gas rate
RE: Annulus gas rate
RE: Annulus gas rate
I can't find the reference to 300 hp engines above. What am I missing? 50 MSCF/day from 0 psig to 50 psig is 100 hp/MMCF or 5 hp. 50-60 MSCF/d of fuel use is a pretty big load (maybe 300 hp, is that what you're talking about?), but not outrageous.
David
RE: Annulus gas rate
RE: Annulus gas rate
Anyway, the 8 cf/hp-hr is an ok number for a small rich burn engine (I think Arrow calls it 9 on the 330, Ajax under part load is closer to 12, but the 8 number shows up pretty often). A big lean burn like the Cat 3516 LE is closer to 6 cf/hp-hr.
David
RE: Annulus gas rate
RE: Annulus gas rate
RE: Annulus gas rate
Look at a Beufort wind scale, it says 2 miles per hour, it says a wind vane will not move much.
For 60 MCFD, the velocity will be 18 miles per hour and small trees will move.
A $40 aneometer can go a long way.
h