Water Production Line Design 1

[Jmoore1]

Hi all, Im wondering if it is possible for gas to go up the production tubing for a CBM well.

IMO, the maximum pressure of the piping needs to be that of the max deadhead pressure of the pump, but is it possible for the gas to go up the production casing and see bottomhole pressure in the case that too much water (or all) of the water is removed by the pump?

Cheers, Jesse

 

[zdas04]

Look up "Turner Critical Rate". This is one of several theories that revolve around a drag model. I covered many of these concepts in my Oil & Gas Journal Article, but it doesn't cover the basics. Most of the wells in the central "fairway" of the San Juan Basin CBM field free flowed for the first 15 years of production. Most are on pumps now, but not nearly all. Also in the San Juan Basin we've put hundreds of wells on "tubing flow control" where there is a flow meter on the tubing, and when tubing flow is greater than critical flow a variable choke opens on the casing to make "extra" gas (some wells are making 2 to 3 times more gas up the annulas than the the tubing, with the tubing keeping water off the formation.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[Jmoore1]

Thanks David....so my understanding of this is you use the smaller diameter tubing to increase the velocity and carry through the liquid? Losses in the tubing would make this a smaller value than through the casing, but its still possible.

 

[zdas04]

The theory says that above a certain velocity, a gas stream can carry considerable liquid. In Turner's work he said that below 100 bbl/MMCF the liquid quantity was irrelevant. Coleman said that it was irrelevant below 220 bbl/MMCF. Both of these values are high enough to address a large majority of the gas wells. Higher velocities in the tubing do result in higher friction losses, but it is rare for this number to be larger than the hydrostatic backpressure caused by not removing the liquid.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.