Gas flowrate reduction in sand producing gas well..

**anuradha** · 03-19-2011, 08:21 PM

Hey all,

Can anybody tell me, if we have one gas well which is a cased hole frac pac well and it has started porducing formation sand, due to which the well has been bean down to some sand free rate / acceptable sand rate.

But recently the well has further bean doown due to sand production, and after few days the well has suddenly dropped the gas flowrate without even changing the choke.
I need to understand this well behaviour.does solid/sand production reduces gas velocity/flowrate. anybody has any supporting paper on that, I have checked the down hole gauges there is sudden increase idown hole pressure..
Thanks
Anu

**ELgharib** · 03-19-2011, 09:22 PM

Find your new HUD, to check if you dont have a sand bridge in your well.

**vinomarky** · 03-20-2011, 12:56 AM

Sounds like some of your sand production has settled into the rathole and is beginning to cover the perforations - this will give you significant productivity drop at same choke setting.

**ELgharib** · 03-20-2011, 01:34 AM

vinomarky, he added this "I have checked the down hole gauges there is sudden increase idown hole pressure.." !!!

**vinomarky** · 03-20-2011, 07:37 AM

Agree - there is some obstruction/fill downstream of the BHP gauge. Depending on where the guage is, it could still be fill or some obstruction further up in the tubing

**anuradha** · 03-20-2011, 08:37 PM

thanx all..

in case if sand production has obstruct the tubing string..then will there be continous & constant gas production....how it has to be determined what has happened...

Pls help me..leme know do u need any details...

**anuradha** · 03-20-2011, 08:39 PM

i mean i have checked the gas rates its continous and constant, there is no reduction...maintained at same rate..

**vinomarky** · 03-21-2011, 01:52 AM

I'm a bit confused - your initial post stated that there was a sudden drop in gas rate, yet now you say it is constant?

If you mean it is now constant, but lower than it was initially, then this is entirely expected. Think of it like a downhole choke

Next step is running slickline in the well to see if you can tag an obstruction - if you are lucky you may even be able to clear the blockage with slickline. More likely you may need a workover and/or coiled tubing cleanout

**ELgharib** · 03-21-2011, 03:48 AM

I agree that he should have sand bridge in the well above the gauges! Think about the deviation of your well to see if a Sliclkline is feasible, you may need a tractor or immediately run a coiled tubing and clean out the sand.

**anuradha** · 03-21-2011, 05:21 PM

hey all,

thanx for giving your valubale thoughts on the issue.

my aplogise if my statements was confusing but i mean to say that the after sudden decrease in gas production and correspondence increase in down hole pressures, now the well is producing at constant rate and maintained at same rate..hope its clear now
one more thing is i have checked choke upstream as well as choke downstream gauges also, there is some increase in choke upstream pressure but because of the gauge fluctuation the increase is not very significant..
What is the possibility of choke bridging in this case.pls discuss this also
N regarding slickline jobs & clearing the obstruction from the well is not very economic solution as its a deep sea well..because of lots of cost involovement issue in this job.

thanx
anu