Field Usage Of Stcks
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FIELD USAGE OF STICKS


FOAM STICKS (WATER) --- Foam sticks have been in use by the oil industry for about 40 years. As gas wells (and oil wells) get older they begin to have problems with water entering the well bore. This begins to create a real production problem when the water column gets over a few hundred feet in height. Pressure is equal to the height of the water column times the density of the fluid. As soon as the water height creates enough pressure to equal the formation pressure, then gas production drops to zero. An alert operator will notice a decrease of gas volume at the surface, which is an indicator that water is probably building up in the well and foam sticks should be used to control this situation. It is much easier to remove a small amount of water from the well than waiting until the well is nearly dead or dead before you begin foam stick treatment. The volume of gas enhancement with foam sticks is so substantial that is pays to begin a regular use program. There are few expenditures in the oil industry that give such a fast payback. Water height in the tubing is rarely a known number; however, a calculation of the reduction in surface pressure at the top of the well can give you some indication of water in the well.

 

EXAMPLE Normal Flow PSI = 1200 PSI

 

Present PSI = 900 PSI

 

300 PSI drop in PSI

 

This drop could indicate 600-700 feet of water has entered the well.

 

(Weight of 333 Ft. of water in 2 3/8 EUE tubing)

 

2 3/8 EUE tubing = 4 BBLS. / 1000 ft.

 

Amount of water = 4 X .3 = 1.2 BBLS.

 

Weight of water = 1.2 X 42 gals. / BBLS. = 50.4 gallons

 

=50.4 gals. X 8.3 lbs. / gal. (PPM of Salt is ignored) = 448.3216

 

The initial slug usage of sticks is often based on .5% by weight of the water in the well.

 

448.32 X .5% (of stick) = 2.24 lbs. Of foam sticks needed

 


In wells with good bottom hole pressure and high water column, we have found that removal (by foam) of the top 25-30% of the water column will allow the well to blow-out and resume normal production until water gradually builds up again which requires additional sticks. Some companies use sticks on a daily basis.


FOAM STICKS (OIL)--- Flowing oil wells need help as they age and water comes in. Enhanced flow can be obtained using oil foam sticks to lighten up the column of oil and also by foaming the water if present. Actual usage is determined in the field but often involves only 1-3 sticks. Treatment should be started early before fluid level gets too high. Once fluid is removed from oil and gas wells using sticks, then a regular program should be started using a very small number of sticks (often 1-2) to get rid of the water as it comes into the well (before the back pressure gets too large). By doing this early, more of the reservoir pressure is available to assist in the blow-out foam part of the treatment.


PURPOSE AND USE OF STICKS IN OIL, GAS, AND WATER INJECTION WELLS Chemical sticks are used to place a small amount of a particular chemical in a well, usually at the bottom or close to the perforated interval. Upon dissolution, the sticks perform a needed function such as scale removal, foaming of water or oil, corrosion inhibition, scale inhibition, paraffin inhibition, release of a tracer dye, and faster well clean up following fracturing treatments. Biocide types of sticks can often be useful for areas such as rat-hole (area below perforation) and other areas not easily treated with liquids.


The success, following the use of chemical sticks, will often result in the saving of considerable money and time. Often, as in the case of water removable from gas wells, the increased production of gas will pay for the treatment in a matter of hours.


The use of scale removers, such as Acid Sticks, reduces the PSI on water disposal wells and then a saving is made in energy costs to run the pumps. This is accomplished by dissolving of acid soluble scale and the surfactant effects contained in the Acid Stick.


In the case of a recently fractured well, it is often difficult and a slow process to get the water flush fluid out of the casing or tubing so the well can clean up and production can be resumed. This can be greatly helped by dropping 15 to 30 Super Foam Sticks TM into the tubing or casing. These sticks dissolve and create foam, reduce surface tension and help slick the pipe surface. The foam generated reduces the Hydro-static head (Back PSI) on the perforated interval and allows more foam which further reduces back PSI and the well starts to clean up faster as the fluid and foam column moves out of the well. This technique can be most cost effective since a swabbing unit cost might be avoided at a savings of 2-4000 dollars depending on well location. In remote of offshore areas the savings can be much greater.


The inhibition of scale, corrosion, bacteria and paraffin by using a stick has benefits where there is no other way to treat the fluid—as in the case of a well that has a packer on the tubing which prevents any use of chemicals down the annulus. Control of bacteria in down-hole and surface equipment can be accomplished using corrosion-biocide type of sticks.


Dye sticks can be useful in tracing suspected leaks in casing and tubing. The testing of subsurface systems using a dye stick has often been done. By inserting a stick in a system that needs to be carefully checked for any fluid leakage on the ocean bottom. After dissolving, pressure is applied to look for leaks

 


Helpful information to know when requesting help or deciding on a stick treatment.

 

Depth of well (T.D.)

 

Area of perforated interval

 

Size of casing and tubing

 

Is a packer in the well,At what depth

 

Bottom hole temperature of well

 

Salt content of water (PPM)

 

Bottom hold pressure (if known)

 

Surface pressure of well

 

How much has surface PSI dropped

 

Original production of well (oil, gas, water)

 

Present production of well (amount of oil, gas, water)

 

Age of well

 

Amount of rat-hole (distance from bottom of perforation to well bottom inside pipe)

 

Known or estimated water column height in tubing or casing. (Needed to calculate weight of water to be removed by foam)