RU2436827C2 - Composition of thermal source for treatment of bottomhole zone of well - Google Patents

Abstract

FIELD: gas and oil production.

SUBSTANCE: composition of thermal source for treatment of bottomhole zone of well consists of granulated ammonia saltpetre of grade B, bi-chromate of potassium, epoxy resin of grade ED-20, plasticiser EDOS, and hardener Agidol of grade AF-2M. As components increasing strength of material of composition and temperature of its combustion compression this composition contains mixture of powders of aluminium of dispersity not over 50 mcm and nitro-acid barium of dispersity not over 0.5 mm at the following ratio of composition components, wt %: said saltpetre 52.5-53.0, potassium bio-chromate 2.4-2.5, epoxy resin of grade ED-20 14.3-14.4, plasticiser of grade EDOS 1.3-1.4, hardener Agidol of grade AF-2M 2.1-2.2, aluminium 10.9-10.5, and nitro-acid barium 16.5-16.0.

EFFECT: raised temperature of combustion of thermal source composition facilitating more deep heating and melting deposits of bottomhole zone of a reservoir, which plug channels and pores, while maintaining level of strength for compression of composition material.

Description

The invention relates to the oil industry, in particular to compositions of a heat source used alone or in devices for thermoimplosion processing of the bottomhole zone of a well.

Thermal sources are made of combustible composite material based on ammonium nitrate and polymer fuel with special additives. Devices that use such thermal source compositions are described in [1, 2, 3, 4] and consist of a sealed air chamber with atmospheric pressure, a diaphragm and a receiving chamber with a combustible solid composite material placed in it, which is referred to in the literature as a thermal source [1 ].

A known composition of a thermal source [2], consisting of two parts, the first part facing the air chamber and formed from a solid with low-gas emission during combustion of the composition. The second part is the main one and is formed from a gas-generating composition during combustion. As the latter, a composition based on granular ammonium nitrate and epoxy was used with the following component ratios, wt.%: Granular ammonium nitrate, grade B - 72, potassium dichromate - 5, epoxy resin ED-20 with PEP hardener (in a 10: 1 ratio) - 23. The advantage of this composition of the heat source is that it is non-detonating, increasing its safe operation, and also consists of non-deficient components with a wide raw material base.

A disadvantage of the known composition of the heat source is its relatively low combustion temperature of 99 ° C, which does not allow its combustion products to sufficiently heat and melt viscous and high-content asphaltene-resinous plugging deposits in the channels and pores of the bottomhole formation zone with hard to recover oil. Another disadvantage of this composition, in addition, is that the heat source material made from it has a relatively low compressive strength of about 20 MPa, which limits its use at bottomhole pressures in the bottom of the well in excess of 20 MPa.

Closest to the proposed invention is a composition in which, as the main (second) part of the heat source [3 or similar 4], a composition based on granular ammonium nitrate and epoxy resin is used in the following ratios of components, wt.%: Granulated ammonium nitrate, grade B 70- 74, potassium dichromate 3-5, epoxy resin brand ED-20 19.5-21.5, plasticizer brand EDOS (TU 2493-003-13004749-93) 1.5-2.0, hardener Agidol brand AF-2M ( TU 38.302-16-378-90) 3.5-4.5. The advantage of the prototype composition is that it is non-detonating, as well as the possibility of obtaining from it the main gas-generating heat source with combustion with higher compressive strength of 40 MPa, thanks to the use of modern plasticizer and hardener of epoxy resin.

The disadvantage of the composition of the heat source according to the prototype is the low temperature in the combustion front (990 ° C), which does not allow sufficient heating and melting of highly viscous and high-content asphaltene-resinous plugging deposits in the channels and pores of the bottom-hole formation zone when it is burned in a borehole fluid medium with hard-to-recover oil, which is a large volume in Russian fields. The present invention solves the problem of increasing the temperature of the combustion of the composition of the heat source, contributing to a deeper heating and melting of the clogging channels and pores of deposits in the bottomhole formation zone and thereby improving its reservoir properties. In this case, the goal is also to achieve the level of compressive strength of the composition material not lower than for the composition material of the prototype. The problem is solved in that in the composition of the heat source for treating the bottom hole of the well, including granulated ammonium nitrate of grade B, potassium dichromate, epoxy resin of grade ED-20, plasticizer of EDOS grade and hardener Agidol of grade AF-2M, according to the invention, the composition additionally contains as components that increase the compressive strength of the material of the composition and its burning temperature, a mixture of aluminum powders with a dispersion of not more than 50 microns and barium nitrate with a dispersion of not more than 0.5 mm in the following ratios Components of the composition, wt.%:

Granular ammonium nitrate, grade B 52.5-53.0 Potassium dichromate 2.4-2.5 Epoxy resin brand ED-20 14.3-14.4 Plasticizer brand EDOS 1.3-1.4 Hardener Agidol AF-2M brand 2.1-2.2 Aluminum 10.9-10.5 Barium Nitrate 16.5-16.0

SUMMARY OF THE INVENTION To create a composition of a heat source with an increased combustion temperature and the strength of its material, the composition of the prototype composition was selected as the basis of the initial formulation, the material from which is non-detonative, i.e. it has high safety (hazard class 4.1), availability and low cost of components, has passed large-scale testing in a variety of conditions at several thousand wells as a thermal source for thermoimplosion treatment of the bottom-hole formation zone.

To increase the combustion temperature, a high-calorie metal additive is usually introduced into the composition, in particular, aluminum powder is used for this purpose. Aluminum, however, reacts poorly chemically with a relatively weak oxidizing agent - ammonium nitrate. To increase the activity of the chemical reaction of combustion of aluminum, it is most advisable to add an addition of barium nitrate to the formulation, which, as shown by experimental studies, reacts very actively with aluminum. As a result of this, the combustion temperature rises significantly, at which ammonium nitrate also begins to decompose more actively and interacts with the components of the composition. As experimental studies have shown, the optimal mass ratio for a mixture of aluminum with barium nitrate is the value at which their stoichiometry is achieved, i.e. the completeness of combustion of a mixture of these components is ensured.

On the other hand, to complete their combustion, it is necessary that these components are in maximum contact with each other in the composition. This is achieved through the use of the finest aluminum powder produced by the industry, in particular the ASD-4 brand, whose dispersion is not more than 50 microns. Moreover, the preparation of the composition involves preliminary mixing of these two components so that finely dispersed aluminum particles are distributed on the surfaces of larger particles of barium nitrate, having a sufficient dispersion, but not more than 0.5 mm. Then this mixture of powders is mixed with a liquid epoxy compound consisting of an epoxy resin of the ED-20 grade, a plasticizer of the EDOS grade and an Agidol hardener of the AF-2M grade. To this mixture, at the final stage, a previously prepared mixture of powders of ammonium nitrate and potassium dichromate is introduced.

The proposed composition of the heat source has a combustion temperature equal to 2360 ° C, which is 2.2 times higher than this indicator for the composition of the prototype. The burning rate of the material in the PVC housing of the heat source in a liquid medium close to the well conditions at a pressure of 0.5 MPa is 0.6 mm / s, at 5.0 MPa - 2.5 mm / s and at 10.0 MPa - 5 mm / s. These data on the burning rate are at the level of indicators for the composition of the prototype. Experimental data on the sensitivity of the composition to shock, determined by the standard method, showed that the proposed composition is non-detonative and belongs to hazard class 4.1 - flammable substances. The compressive strength of the composition material is 46 MPa, which is 15% higher than this characteristic for the prototype composition. The performance of the proposed composition was verified by manufacturing from it a full-scale (10 kg) prototype of a thermal source. Tests conducted at well II of Keremetevskaya Square showed that the heat source burns steadily even at a low bottomhole pressure of 3.9 atm, lasting about 15 minutes, during which the temperature of the wellbore fluid in the processing intervals (950-955 m) was reached and kept constant equal to 117 ° C. In the middle of this period of temperature exposure, the pressure in the face increased to 7.9 atm and at the end of the treatment amounted to 5.1 atm. The volume of fluid flow from the reservoir has tripled. This, apparently, indicates the involvement in the inflow of a previously unaffected section of oil, where the initial pressure was maintained at a higher level.

Thus, the proposed composition of the heat source allows efficiently treating the bottom-hole zone of the formation with hard-to-recover highly viscous oil and with depleted reservoir pressure, while achieving a long-term (up to 15 minutes) high-temperature (up to 120 ° C) effect, which is not possible with the existing well treatment facilities.

Information sources

1. I.F.Sadykov et al. The main results of the development and implementation of new express technologies for thermoimplosion and perforation-implosion treatment of low-yield wells. NTV "Logger", Tver: Ed. AIS, 2001. Vol. 86, p. 57-60.

2. RF patent No. 2075597, cl. ЕВВ 43/25, publ. 03/20/97, Bull. Number 8.

3. RF patent №2138630, cl. 6E21B 43/18, publ. 09/27/1999, Bull. Number 27.

4. RF patent No. 2313663, cl. Е21В 43/18, С09K 8/70, publ. 12/27/2007, Bull. Number 36.

Claims (1)

The composition of the heat source for treating the bottom-hole zone of the well, including granulated ammonium nitrate of grade B, potassium dichromate, epoxy resin of grade ED-20, plasticizer of EDOS grade and hardener Agidol of grade AF-2M, characterized in that it additionally contains components that increase the strength on compression of the composition material and its burning temperature, a mixture of aluminum powders with a dispersion of not more than 50 microns and barium nitrate with a dispersion of not more than 0.5 mm with the following ratios of the components of the composition, wt.%:
Granular ammonium nitrate, grade B 52.5-53.0 Potassium dichromate 2.4-2.5 Epoxy resin brand ED-20 14.3-14.4 Plasticizer brand EDOS 1.3-1.4 Hardener Agidol AF-2M brand 2.1-2.2 Aluminum 10.5-10.9 Barium Nitrate 16.0-16.5