The Right Stick
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Determining The Right Stick

 

The following information will be helpful in determining the right stick for your specific application.


Fluid Column Height:


This is a rarely known number, however, a calculation of the reduction in surface pressure can give you some indication of the fluid column height.

Example:

Normal flow pressure = 1200psi

Present flow pressure = 900psi

Pressure per foot of depth of water is .4330psi

Pressure drop = feet if water in fluid column psi per foot of depth 300 = 693 feet of water in tubing .4330 This is only a rough estimate. Other factors will effect pressure loss between the formation and the well head.


Hydrocarbon Content


The hydrocarbon content in a fluid column will have a dramatic effect on the way a soap stick works. Oil Foam Sticks are designed to foam in fluid columns that consist of 75% or greater volumes of condensate.


Chloride Content


Some soapsticks are specifically designed to perform best in a certain chloride range. While a soap stick may foam well in fresh water, it is possible for it to not foam in 50,000ppm chlorides. For this reason, it is best to know the chloride level in your produced water.


Bottom Hole Temperature


In wells that have a high bottom hole temperature, a soapstick that is harder and has a slower solution rate will fall further through the fluid column before dissolving, therefore foaming a larger section of the fluid column. It can also be beneficial in these wells to have a hard soap stick in a water soluble tube to slow the dissolving rate of the stick.

 

Initial Slug Treatment


Figuring weight of water in 2 3/8" EUE tubing with 333 feet of water. 2 3/8" EUE tubing = 4 BBLS./1,000 ft.

Amount of water = 4 X .3 = 1.2 X 42 gals./BBL. = 50.4 gal. 50.4 gal. X 8.3 lbs./gal. = 418.32 lbs. 418.32 X .005% (% weight of stick) = 2.09 lbs. of foam stick needed.


Additional EUE Factors


Tubing Size     BBLS of fluid per 1000ft

1"           1.1

2"             4

2 1/2"       6

3"             9

3 1/2"     12


Dead Well


Soap Sticks require agitation to generate foam. Combining gas sticks and soap sticks will reduce the hydrostatic weight.