International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
Methods of fighting against scale build-up at the Tuymazy deposit
Kseniya Yuryevna Goryntseva, Raisa Grigoryevna Markova, Alim Feyzrakhmanovich Kemalov
Kazan Federal University, Kremlyovskaya Str., 18, 420008, Kazan, Russian Federation
Abstract:
During
the
oil
production
composition an inhibitor is selected and its
optimum dosage is determined.
continuous scale build-up takes place by using
any operation modes. Increases the pump wear
Key words: oil production, scale build-up,
inhibitors, force fields
on the working faces, presence of non-organic
salts and results in seize of the shaft of
1. INTRODUCTION
electrical centrifugal pump (ECP) and plunger
of the subsurface pump, impeller damage.
Oil production is a complex process
Under these conditions of operation of the
during which a variety of factors shall be taken
mechanized well stock the turnaround is
into account: from geologic structure of
reduced significantly. This is why fighting
deposits and specific impact of the advanced
against scale build-up and prevention of
recovery methods (ARM), in particular tertiary
formation thereof is essential. In practice, the
ones, on the composition and properties of
main task is identification of the composition
fluids produced, to the mineral composition of
and location of salt deposits – the first step is
formation waters, their compatibility with
removal thereof and design of efficient
water used for formation-pressure maintenance
methods. Inhibitor removal time in some
[1, 2]. During oil and gas production salts are
measure depends on the rate of absorption of
deposited on the equipment of a wide range of
salt deposits inhibitor on the productive
deposits and internal surface of field pipelines.
stratum surface. At the same time the slower
Salt gel bearing against the internal surface is
its desorption from the formation is and the
accumulated in production strings, surface
higher the adsorption of the inhibiting matter is
facilities and oil-well tubing forming a layer of
the more efficient and long-lasting is scaling
a few centimeters thick. Increased scale build-
prevention. Scaling prevention is achieved
up results in reduction of the production rate
with the use of inhibitors at optimum dosages
due to increase in the piping surface roughness
the values of which in formation water are
and the flow passage is reduced. Therefore,
determined by content of salt-forming ions
production is declined and the pressure is
Са2+ and НСО3-. On the basis of results of
built-up. It becomes impossible to reach the
experimental works performed on analysis of
subjacent well sections as crystals grow at the
efficiency of scaling for waters of different ion
45360
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
same
time
the
pipe
flow
is
reduced
attention shall be paid to selection of the
significantly.
necessary methods of fighting against scaling
The first cause of scale build-up is
which will allow providing the maximum
mixing of chemically incompatible waters of
efficiency with account for the economic
different composition, the second one –
viability in the specific field conditions [4].
variation
of
pressure,
temperature,
gas
Let’s consider the Tuymazy deposit. At
liberation. All of this results in that the actual
this deposit chemical methods are actively
concentration exceeds the equilibrium one and
used since use of chemical reagents-inhibitors
the substance fall-out from the solution takes
is the most efficient one from among the
place.
existing methods of scale build-up prevention.
As of today this issue is topical for the
For inhibition of carbonate and sulfate scale
oil industry as most of mature deposits with
inhibitors СНПХ-5301, СНПХ-5312С are
complicated
are
recommended, ferrous scale – СНПХ-5313
characterized by high watering of products
designed by NIINEFTEPROMKHIM (Kazan),
which in its turn is a favorable condition for
most frequently used for relatively high-
formation of different deposits [7, 8].
permeability formations. For fighting against
production
conditions
There are reagentless and chemical
sulfate and sulfide-containing scale inhibitor
methods of scaling prevention. Chemical ones
ПАП-С-1 designed by the ‘IPZ Intech’ LLC
are: use of highly-mineralized water, use of
can be used, the new reagents of the
different kinds of inhibitors. Reagentless:
СОНСОЛ-2001 and СОНСОЛ-2002 series
structural alteration of equipment, protective
(carbonates and calcium, ferrous and barium
coating of the piping surface as well as
sulfates) designed by the CJSC ‘Pilot plant
exposure of the solution to magnetic force
NEFTEKHIM’ as well as removers-inhibitors
fields.
СОНСОЛ-3003м, СОНСОЛ-3001 designed
The efficiency of measures aimed at
fighting
against
scale
build-up
by
for removal and prevention of carbonate and
oil
sulfide-containing scale [4].
production depends on the integrated approach
The
area
of
application
of
scale
to solution of this issue. It is necessary to
inhibitors regardless of the operation mode –
know the physico-chemical processes and
all permanently operated wells. Prevention of
causes related to scale build-up under different
deposition of non-organic salts on pumping
conditions of oil occurrence, to be able to
equipment and production well is achieved by
forecast in advance, timely prevent and be
means of treatment of the produced water with
firmly in control of possible appearance of salt
scale inhibitors using different techniques.
deposits during the well operation. Special
There is the optimum value of content of
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
inhibitors ensuring scaling prevention for
range of capacities within which inhibitor
water produced from each well complicated
solution can be set in the bottom hole
with scale.
formation [5].
It is not recommended to perform well
1. PRELOADING THE SCALE
INHIBITOR
SOLUTION
IN
THE
BOTTOMHOLE FORMATION ZONE
The technology used in all wells
treatment using this technology upon the low
reservoir properties.
operated either periodically or permanently
regardless of the operation mode for the entire
Table 1. Scale inhibitors recommended for deposits of the Tuymazy oil production department
Kinds of non-organic
salts
Scale inhibitor
Dosage, mg/l
СНПХ-5312С
ПАП-С-1
15-20
15-20
Gypsum
СОНСОЛ-2002а
15-25
СНПХ-5312С
ПАП-С-1
25-30
15-20
Carbonates
Barium salts
Sulfide-containing
СОНСОЛ-2002а
20-25
СОНСОЛ-2001Б
20-35
ХПС-007
СНПХ-5313
ПАП-С-1
30-40
50-70
30-45
Notes
Modified according to
the conditions of the
Tuymazy
oil
production department
Modified according to
the conditions of the
Tuymazy oil
production department
Modified according to
the conditions of the
Tuymazy oil
production department
measuring devices through a capillary cable or
2. CONSTANT DOSING WITH THE
armored capillary. In order to provide constant
USE OF MEASURING DEVICES
The area of application – all wells
inhibitor dosing a vessel, на устье скважины
equipped with ESP unit (electrical submersible
устанавливается емкость, dosing apparatus
centrifugal pump unit) or EDP (electrical
are mounted on the well mouth and connected
diaphragm pump unit) and wells equipped
through the known circuits to the annular
with sucker-rod pumping unit with the
space.
capacity over 5 t/day.
Let’s calculate inhibitor demand for the
It is recommended to perform constant
technology of constant inhibition of well
dosing of scale inhibitor with the use of
troubles. The volume ratio of water in the
45362
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
well-produced products (
is calculated
according to the formula
Since 2600
)
The inhibitor amount dosed into a well
=2080>1800 then water from the bottom hole
(P, kg/day) is calculated according to the
is not completely recovered and period
formula
inhibition technology may be used for scaling
prevention.
- During the first 10 days of the ‘shock
Density of gas-saturated fluid (
dosage’ mode -
is
calculated according to the formula
=5 30=150г/т;
P=150 0,132 1005/
=0,399 kg/day
- Upon expiry of the 10-days term in the
‘optimum dosage’ mode -
The fluid volume in the bottom hole
;
P=30 20 0,132 1005/
and within the annular space (
=0,080
is
calculated according to the formula
kg/day
3. PERIODIC FILLING
Regardless of the operation mode the
The inhibitor amount supplied (P, kg)
technology is used within the entire range of
supplied to the bottom hole is calculated
capacities and in all wells that are operated
according to the formula
constantly.
P=2,0 30 793 0,15
Periodic filling of scale inhibitor in the
(20 30+18,18)/
,
annular space of the flowing well may be
performed either with the use of pumping
Where К=2,0 – rate of increase in the
method or the device (dropper) [6].
inhibitor consumption taking into account
Let’s calculate the inhibitor demand for
irregularity of inhibitor recovery from the well
the technology of periodic inhibition of well
bottom hole;
troubles
Treatment frequency – every 30
Water recovery from the bottom whole is
days.
estimated
Since P=4,4 kg then during the by initial
The Reynolds number for oil is
treatment it is recommended to fill in 50 kg of
calculated according to the formula
the inhibitor.
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
If non-organic salts have been already
of the scale bridge with the solution of 20-25
deposited it is recommended to remove them.
volume ratios of caustic soda with further
Prior to well treatment for removal of
removal of reaction products with 15 volume
non-organic salts deposits in the subsurface
ratios of hydrochloric acid or mechanically [5].
equipment and production string they shall be
The solvent-inhibitor consumption is
previously cleared out of (ARPD) asphalt,
presented in the Table 2
resin and paraffin deposits, such cleansing may
be performed by means of treating the
downhole pumping equipment with the ARPD
solvent in the amount 1,5-5,0 tons.
By using the scale inhibitor СОНСОЛ3003м no preliminary treatment with the
ARPD solvent is required.
Removal
of
calcium
sulfate
salts
(gypsum) is performed by means of treatment
Table 2. Consumption of solvent-inhibitors recommended for wells of the Tuymazy oil
production department.
Scale inhibitor
СОНСОЛ-3003м
СОНСОЛ-3001
Well capacity, m3/day
1-5
5-15
15-25
25-50
50-100
100-200
Reagent consumption
per one treatment, m3
0,025
0,050
0,050
0,100
0,150
0,200
Notes
Inhibitor consumption
and treatment frequency
is specified on the basis
of field data, however,
at least once a month
is achieved. The prevention methods shall be
4. CONCLUSIONS
It was established that use of scale
used rather than scale removing ones.
inhibitors considered in this paper allows not
CONFLICT OF INTERESTS
only removing the already formed carbonate
The author confirms that the data provided does
scale but preventing formation thereof due to
not contain the conflict of interests.
pH reduction.
ACKNOWLEDGMENTS
5. SUMMARY
The work is performed according to the
Thus, on the basis of calculations the
Russian Government Program of Competitive
conclusion may be drawn that by constant
Growth of Kazan Federal University.
inhibiting the minimum inhibitor consumption
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 10, Number 24 (2015) pp 45360-45365
© Research India Publications. http://www.ripublication.com
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DOI: