RU2132453C1 - Reagent for removing asphalt-resin-paraffin depositions - Google Patents

Abstract

FIELD: oil and gas production industry. SUBSTANCE: reagent is intended for removing depositions created in oil beds, on wall of wells, in pipelines. It can be applied in process of production, transportation, storage and processing of oil and gas condensates. Reagent contains pyrolysis resin freed from gasoline and having initial boiling point of 200-220 C in amount of 2-6 mas.%, and solarodistillate mixture. Aforesaid reagent is characterized by high efficiency and low cost. EFFECT: higher efficiency. 2 tbl

Description

 The invention is intended for the removal of asphalt-resin-paraffin deposits (paraffin deposits) formed in oil reservoirs, on the walls of wells and pipelines, and can be used in the extraction, transportation, storage and processing of oil and gas condensates.

Known reagent [1] for removing asphalt-resin-paraffin deposits, consisting of 4,4-dimethyl-1,3, dioxane (DMD) and 4-hydroxyethylated alkyl phenols (OP-4) in ratios, wt.%:
OP-4 - 0.005 - 4.0
DMD - Else
The main disadvantage of this reagent is its weak detergent-dispersant properties and environmental restrictions for use due to the presence of phenolic base hydrocarbons in it.

Known reagent [2], consisting of a mixture of stable gas condensate and surfactants (lower alkyl alcohols or mixtures thereof), in which, to increase the effectiveness of the action, thioalcohols are additionally contained in the following proportions, wt.%:
thioalcohols (C ₂ -C ₆ ) - 0.8 - 3.0
lower alkyl alcohols (C ₁ -C ₃ ) - 0.1 - 0.5
stable gas condensate - the rest
The main disadvantage of this reagent is its limited use due to its high cost and contamination of produced oil or gas condensate, since it includes expensive specially synthesized thioalcohols (sulfur-containing compounds). Removing the latter from oil or condensate is almost impossible.

The closest analogue is the composition for the removal of paraffin wax is a salt-distillate mixture (SDS) [3], consisting in wt.%:
from salt distillate - 40
gasoline - 30
kerosene - 40
The disadvantage of the reagent prototype is its low effectiveness, since it does not contain bi-and polycyclic aromatic hydrocarbons - solvents of asphaltenes that are part of ASPO.

The purpose of the invention is to increase the efficiency of the use of the reagent in the flushing processes of wells, pipelines and oil storage facilities while reducing its cost. This goal is achieved in that the salt-distillate mixture (SDS) is supplemented with a topped pyrolysis resin with a boiling point of 200 - 220 ^o C in ratios, wt.%:
pyrolysis topped resin - 2.0 ... 6.0
salt-distillate mixture - the rest
In the composition of the proposed reagent, the salt-distillate mixture performs the function of a solvent mainly of resins and paraffins adsorbing and crystallizing on asphaltene particles in the ARPD structure, and the topped resin, as a highly aromatized component, is a function of the asphaltenes solvent, i.e., the remover of the centers of formation and growth of ARPDs.

The salt-distillate mixture (SDS) is an oil fraction with a density of 649 - 815 kg / m ³ and boiling temperatures of 120 - 130 ^o C. It is obtained when the oils are stabilized under conditions of NGDU. Depending on the stabilization mode, it contains up to 27, 68 ... 48, 63 wt.%, Dissolved hydrocarbon gases mainly C ₄ ... C ₅ .

The topped pyrolysis resin with a boiling point of 200 - 220 ^o C lacks gasoline fractions and aromatic hydrocarbons (benzene, toluene and xylons) - the most important products for the production of gasolines and petrochemicals. Therefore, it is a low-value waste subject to rational disposal. The topped pyrolysis resin has a density of 1.050 to 1.095 t / m ³ , and contains 45.6 - 49.4 wt.% Bi- and polycyclic aromatic hydrocarbons.

 The effectiveness of the proposed reagent was tested on the example of dispersion and dissolution of two samples of paraffin deposits formed in the wells during the extraction of paraffin (well 16496) and asphalt paraffin (well 20868) oil NGDU Almetyevneft. The compositions of paraffin are given in table. N 1.

The proposed reagent was tested for dispersing and dissolving ability in relation to the two described samples of paraffin. The reagent was prepared by adding to the salt-distillate mixture (SDS) a stripped pyrolysis resin with a boiling point of 200 ^° C in an amount of 0.5; 2.0; 3.0 and 4.0: 6.0 wt. % To compare the effectiveness of the action at the same time tested the prototype of the reagent [3], prepared according to its description.

The tests were checked by the following procedure:
The reagent for the treatment of paraffin deposits with a volume of 30 cm ^{3 was} poured into a glass tube with a flat bottom and a ground stopper. The cork has a “shank”, to which a strainer with a paraffin sample weighing about 1 g was hung on the hook. The strainer is made of stainless steel with 1.5x1.5 mm cells. At the bottom of the test glass is an iron plate of a magnetic stirrer. To maintain a constant temperature, the test device, together with the stirrer, is placed in a thermostat. After reaching the set temperature (10 ^o C) in the thermostat, the mixer and the stopwatch-clock were switched on. After the accepted mixing time, an AFS sample with a strainer was removed from the glass and placed in a fume hood, dried at a temperature of 105 - 110 ^o C for 30 minutes and weighed to an accuracy of 0.01 g. Then the basket with a sample of ASPA was again introduced into the glass without change of reagent and the procedure for the impact on the AFS between weighings was repeated several times until the total processing time of 180 minutes

 The test results of the reagent compositions are given in table. 2.

 From the table. 2 it follows that the effectiveness of the proposed reagent on the AFS samples is significantly higher than the prototype reagent, and the greatest effect is observed if the stripped pyrolysis resin in the SDS is added 2 ... 6%.

 An increase or decrease in the amount of reagent in the SDS does not significantly increase the solubility and dispersion of the ARPD.

 Thus, the proposed reagent is an effective tool for removing asphalt-resin-paraffin deposits. Its components are petroleum products, and therefore cannot adversely affect the properties of oils and gas condensates and their refining processes.

 The use of the reagent is carried out by pumping into the annulus of the well and lifting it with tubing to the wellhead. Injection is carried out in a volume equal to the sum of the volumes of the annulus and tubing strings at a speed that ensures a developed turbulent regime of fluid movement. The Reynolds number in this case should be from 20,000 to 50,000.

Sources of information
1. A.S. USSR N 1495353, class E 21 B, 37/06, 1989.

 2. A.S. USSR N 1162947, class E 21 B, 27/06, 1983.

 3. A.S. USSR N 1002541, class E 21 B, 43/25, 1983.

Claims (1)

Reagent for removing asphalt-resin-paraffin deposits, containing a salt-distillate mixture, characterized in that the mixture further comprises a topped pyrolysis resin with a boiling point of 200 - 220 ^o C in the following respects, wt.%:
Pyrolysis topped resin - 2-6
Salt-distillate mixture - Else

Images