RU2534142C1 - Acid-generating solid-fuel composition for treatment of oil wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: acid-generating solid-fuel composition includes the following components, wt %: ammonium nitrate 35-40, thrifluorochloroethylene copolymer with vinyledine fluoride 5, elastomeric copolymer of vinyledine fluoride and chlorotrifluoroethylene with particle size of 0.5-1.5 mm 10-12, polyvinylchloride with mol. mass of 25-50 thous. 43-50.

EFFECT: increased combustion temperature, combustion rate and calorific value of acid-generating solid-fuel composition at high combustion stability in the wide pressure range, increased efficiency of the impact on bottomhole formation zone matrix comprised of carbonate and terrigenous rocks and on silicate impurities in the bottomhole zone, reduced slagging, capability of the composition to be processed by extrusion method.

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Description

The invention relates to the oil industry and is intended for the treatment of the bottom-hole formation zone, composed of both carbonate and terrigenous rocks, as well as silicate contaminants formed in the bottom-hole zone during drilling and cementing of wells.

Known solid fuel acid-generating composition for treating oil wells containing ammonium nitrate, hexochloroethane and polyvinyl chloride resin, in the following ratio, wt.%:

ammonium nitrate 32-33 hexochloroethane 57-58 polyvinyl chloride resin 10,

see RU Patent No. 2386026, IPC E21B 43/27 (2006.01), 2010.

The disadvantage of this technical solution is the low processing efficiency of the bottomhole formation zone, composed of terrigenous rocks. In addition, the composition has a low combustion temperature and burning rate, as well as low specific heat of combustion.

Closest to the invention is a solid fuel acid generating composition for treating oil wells containing ammonium nitrate, hexochloroethane and fluoroplastic grade FP-4, in the following ratio, wt.%:

ammonium nitrate 32-33 hexochloroethane 51 -53 polytetrafluoroethylene - ftoroplast FP-4 15-16

During thermal degradation, the composition emits a mixture of hydrofluoric and hydrochloric acids, which allow acidic effect on the bottom-hole zone of the formation, composed of both carbonate and terrigenous rocks, as well as on silicate contaminants formed in the bottom-hole zone during drilling and cementing of the well,

see RU Patent No. 2469189, IPC E21B 43/27 (2006.01), C09K 8/72 (2006.01), 2012.

The disadvantages of this technical solution are not a high combustion temperature, the burning rate of the composition, which leads to a low intensity of acid exposure to the skeleton of the rock. In addition, stable combustion is observed only at borehole pressures of at least 5 MPa. At the same time, a significant amount of solid products (slags) are formed in the combustion process, up to 20% of the initial mass of the composition, which pollute the bottom-hole zone of the formation and reduce its filtration characteristics. The composition in its composition contains hexachloroethane, which is a toxic unstable substance with a sublimation temperature of about 80 ° C. This imposes high requirements on the organization of air purification systems for the working area during processing of the composition and sealing of products made from it. The composition cannot be processed into a product by a high-performance extrusion method.

The objective of the invention is to provide a solid fuel acid-generating composition having an increased combustion temperature and burning rate, high specific heat of combustion, high combustion stability in a wide pressure range, with less slag formation and capable of being processed by extrusion.

The technical problem is solved in that a solid fuel acid generating composition containing ammonium nitrate, fluoroplastic, as a fluoroplastic, it contains a copolymer of trifluorochlorethylene with vinylidene fluoride, additionally contains an elastomeric copolymer of vinylidene fluoride and chlorotrifluoroethylene with a particle size of 0.5-1.5 mm and polyvinyl chloride. mass of 25-50 thousand, with the following ratio of components, wt.%:

ammonium nitrate 35-40 trifluorochloroethylene copolymer with vinylidene fluoride 5 vinylidene fluoride elastomeric copolymer and chlorotrifluoroethylene with a particle size of 0.5-1.5 mm 10-12 polyvinyl chloride mol. masses 25-50 thousand 43-50

The solution to the technical problem allows to increase the combustion temperature, the burning rate and the specific heat of combustion of a solid fuel acid generating composition with its high combustion stability in a wide pressure range, which improves the efficiency of the impact on the skeleton of the bottomhole formation zone, composed of both carbonate and terrigenous rocks, as well as silicate contamination in the bottomhole zone, reduce slag formation and give the ability of the composition to be processed by extrusion.

Characterization of the components of a solid fuel acid generating composition:

ammonium nitrate is an oxidizing agent, which is used as granular ammonium nitrate (ammonium nitrate) grade B according to GOST 2-85;

a copolymer of trifluorochlorethylene with vinylidene fluoride, which is used as a powdery fluoroplastic brand F-32L B according to OST 6-05-432-78;

elastomeric copolymer of vinylidene fluoride and chlorotrifluoroethylene, which is used as a powder fluororubber grade SKF-32 grade 2 according to GOST 18376-79;

polyvinyl chloride, which is used as a powdery polyvinyl chloride grade PVC-S-4700-G according to GOST 14332-78.

A solid fuel acid generating composition is obtained by mechanical mixing of the components.

For a better understanding of the invention provide examples of specific performance.

Example 1

The inventive composition is prepared in a drum mixer by mechanical mixing of ammonium nitrate, a copolymer of trifluorochlorethylene with vinylidene fluoride - powdered fluoroplastic grade F-32L B, an elastomeric copolymer of vinylidene fluoride and chlorotrifluoroethylene - fluororubber grade SKF-32 with a vinyl chloride size of 0.5 mm PVC; -C-4700-W with a molecular weight of 25 thousand in the following ratio of components, wt.%:

ammonium nitrate 35 trifluorochloroethylene copolymer with vinylidene fluoride 5 vinylidene fluoride elastomeric copolymer and chlorotrifluoroethylene 10 polyvinyl chloride with mol. weighing 25 thousand fifty

Examples 2-3 are similar to example 1, data on the composition and its properties are shown in table 1.

The delivery of a solid fuel acid generating composition to the bottomhole formation zone is carried out using a sealed device on a cable cable. The device is a combustible shell with a built-in means of initiating combustion,

see, for example, RU Patent No. 2144630, IPC E21B 43/25, E21B 43/26, 1999.

Samples of fuel with a diameter of 10 mm are made from the resulting composition by extrusion. The height of the samples varies depending on the nature of the studies. The burning rate of the samples is determined in a constant pressure device that simulates downhole conditions at a pressure of 0.1-10 MPa. The solids content in the combustion products is determined by weighing a quartz sampler placed in a constant pressure device before and after burning fuel samples. The mass of acids released during the combustion of one kilogram of solid fuel composition, the specific heat of combustion of the composition is determined by calculation, see Alemasov V.E. et al. Textbook "Theory of Rocket Engines", ed. V.P. Glushko. - M.: Mechanical Engineering, 1980, p. 44.

The composition and its properties are shown in table 1.

Table 1 Composition Case Studies prototype The composition according to the claimed object, wt.% No. 1 Number 2 Number 3 one 2 3 four 5 Ammonium nitrate 33 35 37 40 Ftoroplast of the F-32L V brand 5 5 5 SKF-32 brand fluororubber with a particle size of 0.5 mm - 10 - 12 SKF-32 brand fluororubber with a particle size of 1.5 mm - - eleven - Polyvinyl chloride grade PVC-S-4700-W, with a molecular weight of 25 thousand - fifty - 43 Polyvinyl chloride grade PVC-S-4700-W, with a molecular weight of 50 thousand - 47 - Ftoroplast brand FP-4 16 - - - Hexachloroethane 51 - - - Composition properties The mass of acids in the numerator is concentrated hydrochloric / in the denominator is hydrofluoric acid released during the combustion of one kg of fuel sample, kg / kg 0.48 / 0.11 0.48 / 0.11 0.48 / 0.115 0.49 / 0.12

Table continuation one 2 3 four 5 Slag formation
fuel samples relative
device mass,% 15-20 3-5 2-4 1-3 Combustion temperature of fuel samples, K 989 1278 1315 1356 Specific calorific value of fuel samples, kJ / kg 1600 1850 1960 2110 The burning rate of fuel samples, mm / s, at a pressure of 0.1-5 MPa Does not burn 1-2 1-3 2-4 The burning rate of fuel samples at a pressure of 5-10 MPa 1-2 3-5 4-6 5-7

As can be seen from the examples of a specific implementation, the solution of the technical problem allows to increase the combustion temperature, the burning rate, and the specific heat of combustion of the solid fuel acid generating composition with its high combustion stability in a wide pressure range, which makes it possible to increase the efficiency of the impact on the skeleton of the bottom-hole formation zone, composed of carbonate, and terrigenous rocks, as well as silicate contamination in the bottomhole zone, while reducing slag formation during its combustion and giving the ability compositions are processed by extrusion.

Claims (1)

A solid fuel acid generating composition for treating oil wells, containing ammonium nitrate, fluoroplastic, characterized in that it contains a trifluorochlorethylene-vinylidene fluoride copolymer as a fluoroplastic, and further comprises an elastomeric copolymer of vinylidene fluoride and chlorotrifluoroethylene with a particle size of 0.5-1.5 mm and polyvinylchloride. mass of 25-50 thousand with the following ratio of components, wt.%:
ammonium nitrate 35-40 trifluorochloroethylene copolymer with vinylidene fluoride 5 vinylidene fluoride elastomeric copolymer and chlorotrifluoroethylene with a particle size of 0.5-1.5 mm 10-12 polyvinyl chloride mol. masses 25-50 thousand 43-50