Paraffin Control Solubilizes Paraffin Back into the Oil

Case Study:
Oil & Gas Industry
Paraffin Control Prohibits Wax Crystallization,
Solubilizes Paraffin Back into the Oil
Field tests have proven that Paraffin Control, a surfactant based formulation, is safer, more
effective and economical than hot oiling for eliminating wax buildup in the formation and
production equipment as well as on the tubulars and downhole pumps.
One of the most familiar reasons for production down time and workovers is wax buildup, which
occurs when paraffins crystallize out of the crude oil, coating tubulars, equipment, pipelines and the walls
and bottoms of storage tanks. Paraffins are saturated, non-polar hydrocarbons with chain lengths of C20
through C50. The term “
wax”may be used interchangeably with paraffin.
The three primary variables of wax in crude oil that are of particular interest during production
are:
 The temperature at which the wax will crystallize and come out of solution from the crude oil.
 The amount of wax in the crude oil.
 The formation of micro reverse-emulsions in the produced water.
Dur
i
ngc
r
ud
eo
i
lp
r
odu
c
t
i
o
n,t
heoi
l
’
st
e
mpe
r
a
t
ur
ewi
l
ldecline from the time it leaves the
formation until it reaches the refinery unless heat is added. When the temperature drops below the wax
crystallization point, the wax will plate out from the oil and form crystals that will grow in volume and
precipitate onto tubular and equipment surfaces. This crystal growth can take place:
 In the formation near the well bore.
 Inside the production tubing or casing.
 In pipelines.
 Inside treating and separation equipment.
 In storage equipment.
If there is sufficient wax buildup, the flow of oil will be restricted or could be completely
blocked. A secondary, often unrecognized, problem can develop when microscopic micelles (micro
reverse-emulsions) containing wax are suspended in the produced water. When this produced water is
reinjected into the formation, the wax can plug the tubing perforations and pore throats, and even plug off
the formation.





Several procedures have been created to overcome these problems, including:
Reducing heat loss utilizing insulation.
Adding heat to the system.
Hot oiling.
Solvent flushing.
Chemical treatment.
Insulating the lines and adding heat are the most effective solutions on the surface. Insulation is
endorsed because the other procedures require shutting down production during treatment. However,
insulating the lines also requires an abundant capital outlay, and the operating expense cannot always be
financially justified. Furthermore, this treatment cannot be applied to downhole waxing problems.
Hot oiling is the most frequently used procedure for downhole paraffin treatment. Crude oil is
heated to a temperature significantly above the wax crystallization point, then it is circulated through the
well, pipelines and equipment exhibiting wax build up. The advantage of hot oiling is that the end
product can be put directly into the production tank. The drawbacks of hot oiling are:
1
 Large pieces of equipment and a heat source are required.
 Depending upon temperature of the oil, the hot oiling procedure may not completely de-wax the
equipment. Hard waxes require a much higher temperature to melt; thus hard wax can build up over a
period of time.
 Production is suspended during the hot oiling process resulting in down time.
 Melted wax is introduced through the perforations into the formation where it cools and crystallizes,
blocking reservoir flow to the well bore. With repeated hot oiling procedures, significant damage and
loss of production can occur.
 The high temperature of the volatile oil that could result in fire or explosion makes worker safety a
concern.
Solvent washing is comparable to hot oiling, except a solvent such as xylene is used instead of
heat to remove the paraffin. The advantage of the solvent washing is that it does not depend on
temperature to melt the paraffin. It is effective for high-melting point waxes and can be sent directly to
the production tank. The disadvantages of solvent washing are:
 Solvents are costly.
 Solvents are usually unstable, unpredictable materials.
 Solvents are more flammable than the crude oil, and sparks, friction or static electricity can result in a
flash fire, threatening workers and equipment.
Chemical treatment involves the addition of small quantities of chemicals into a batch of crude oil
or produced water, or continuously fed down the backside of the well. The chemicals transform the
crystal formation mechanism, dispersing the paraffin back into the oil. When batch treating, these
chemical solutions are circulated similarly to the hot oiling process. Sometimes two chemicals have to be
used, one to disperse wax into the oil and another to demulsify the wax from the produced water. The
major benefit of chemical treatment is that it prevents wax formation rather than treating the problem after
it occurs. Also, this treatment requires less equipment than hot oiling and solvent flushing.
Solution: Paraffin Control Treatment
A surfactant based product called Paraffin Control, manufactured by Enviro Clean Products,
L.L.C. of Oklahoma City, Oklahoma, has been designed and field tested for several years to measure its
proficiency and performance in de-waxing wells, pipelines, storage tanks and wax pads in treaters.
Paraffin Control acts in four distinctive ways:
 It prevents the paraffin from crystallizing below its crystallizing temperature.
 It solubilizes the wax back into the oil after it has plated out.
 It serves as an excellent emulsion breaker, both downhole and in the production equipment.
 It also breaks the micro reverse-emulsions of wax, oil and water that remain suspended in the
produced water.
Because of the success of these initial field tests, additional case studies were performed to
ascertain the mechanism that makes Paraffin Control so effective at de-waxing and demulsifying.
Case Study # 1:
A producer in Pontotoc County, southeastern Oklahoma
o
pe
r
a
t
e
sa2,
30
0’Booc
hSa
ndwe
l
l
.Hi
s
t
or
i
c
a
l
l
ywhe
nt
h
ewe
l
l
was pulled for pump repairs, a significant amount of hard, dry
wax was accumulated on the rods. If too much time had passed
since the previous rod job, the well would have to be stripped.
This procedure is both messy and expensive, costing
approximately $5,000 to perform. In late 2005, the operator
treated the well by dumping 5 gallons of Paraffin Control down
2
the tubing/casing annulus and circulating the well using the downhole pump for 24 hours. The well was
then put back on production. This procedure has been repeated every 6 months since the initial treatment.
The well has been pulled twice since the treatments began. Each time the rods have been essentially
clean with only small amounts of soft paraffin on some of the rod boxes.
Case Study #2:
An oil and gas operator in Hughes County, southeast Oklahoma has 3 wells producing into a
common tank battery. 3-2”pol
ypi
pef
l
owl
i
ne
sl
e
a
v
i
ngt
hewe
l
l
swe
r
ebu
r
i
e
d8t
o10i
nc
he
sbe
l
ow
surface. The lines merged together to become a single line before reaching the tank battery. The wells
had a history of making paraffin and, over time, the flowline pressure had increased from 5 psi to 38 psi
due to paraffinic build up and restriction. The wells were each treated with 5 gallons of Paraffin Control.
The wells were circulated for 24 hours and then put back on production. Within a week after the
treatments, the flowline pressure had gradually decreased back to its original 5 psi. It should be noted that
in spite of the significant amount of paraffin removed from the wells and flowlines, there was no increase
in BS&W in the stock tank and the load of oil was sold with no further treatment required.
Summary
A prevalent finding in all the well de-waxing field tests and case studies is that the Paraffin
Control treatments lasted significantly longer than any other treatment. In the beginning, it was
hypothesized that Paraffin Control was coating the tubing and preventing wax build-up. However,
subsequent studies have shown that some Paraffin Control remained in the rathole fluids at the bottom of
the well. Only minor required to be effective in treating the produced fluids, typically between .0002 and
.0005 ppm. Therefore the Paraffin Control diluted into the rathole fluids can many times last for 30-180
days, depending upon well conditions.
Furthermore, test results indicate that Paraffin Control works by creating micro-emulsions of oil
and water, with the wax attached to the emulsion phase, which stays suspended in the oil. It should be
noted that the water in the micro-emulsions is considerably less than typical BS&W standards, thus the
solution can be sent straight to the refinery with the produced oil. Additionally, by dispersing the
paraffins back into the oil, the Paraffin Control treatment minimizes a potential waste stream while
creating additional revenues through increased sales volume and decreased disposal expenses.
Paraffin Control has proved to be both an effective dispersant and demulsifier. In addition, it is
non-toxic, biodegradable and non-flammable. It is a safe and effective method to treat wells, pipelines,
tanks and vessels for paraffin buildup. In the current trend of waste reduction, environmentally sound
practices, and the never ending pursuit to increase worker safety, Paraffin Control has proved to be a
worthy solution for paraffin problems.
For more information please contact your local distributor or:
Enviro Clean Products & Services
405.373.4545 OK
www.EnviroCleanPS.com
[email protected]
IMPORTANT NOTICE: The information and statements contained herein are believed to be reliable but are not to be construed as a warranty or
representation for which we assume legal responsibility. Users should undertake verification and sufficient testing to determine the suitability for
their own particular purpose of any information or products referred to herein. No warranty of fitness for a particular purpose is made. Always
use EC products in conformance with all applicable regulations.
3
`