RU2224103C1 - Device and method for thermochemical treatment of a productive layer - Google Patents

Abstract

FIELD: petroleum extracting industry. SUBSTANCE: method includes pumping of combustible oxidizing compound with 0-82% ethanollaminenitrate, saltpeter and water through a column of lifting pipes. Then igniting material is brought to the location of combustible oxidizing compound in amount of 10-50% of said compound mass. As combustible oxidizing compound at least one of the following materials is used: lithium hydride, sodium hydride, potassium hydride or sodium nitrite or potassium nitrate. Hydrides are used in form of extruded tablets covered with paraffin or rosin. Nitrites are used in form of saturated water solution. Device has a column of lifting pipes, lowest of which is first or main pipe. Main pipe comprises two additional pipes, placed one inside other coaxially to the main pipe. All three pipes are hermetically interconnected by a connecting device, thus forming a free space inside the pipes for discharging of combustible oxidizing compound into space between second and third pipe. Enclosure at upper and lower parts is delimited with valves. Shear pin is placed between said valves, densely adjoining with pressurizing stopper. Igniting material is placed in the enclosure. Another shear pin is placed at the top part, densely adjoining with pressurizing stopper. At the low part pressurizing stopper and shear pin are provided, densely adjoining the return valve. Device may also comprise a packer between pipe casing and the main pipe. EFFECT: expanded technological capabilities of both device and method. 2 cl, 1 dwg, 1 tbl

Description

The invention relates to the oil and gas industry, in particular to methods for thermochemical processing of productive formations: oil, gas condensate and devices for its implementation, and can be used in the development of oil, gas and gas condensate fields.

A known method of thermochemical treatment of the bottom-hole formation zone, including pumping into the treatment zone through a tubing string a fuel-oxidizing composition (GOS) containing initial components in the following ratio, wt.%: Urea 18.0 - 30.0; nitric acid 4.0 to 6.0; acetic acid 4.5 to 5.5; potassium permanganate 0.01-0.02; isopropylmethacarborane 0.3-3.0; water 13 - 18 and ammonium nitrate 38 - 60, the subsequent introduction of a combustion initiator containing aluminum (10-30 wt.%) and chromium oxide (70-90 wt.%) in an amount of not more than 10% of the mass of GOS into the GOS location zone (RU 2126084 C1, E 21 B 43/24, 1999). Thermochemical treatment of the bottomhole formation zone in the known method is carried out by separate supply of GOS and the initiator of combustion through the column of tubing.

The method allows to increase the efficiency of the well development process, however, it is limited by the use of the indicated GOS compositions and initiators by processing only the bottom-hole zone of the oil reservoir, which is determined by the tubing device, and, in addition, due to the almost simultaneous supply of reagents, the reaction can begin in the perforation zone, which is often undesirable moment.

There is a method of thermochemical treatment of the bottom-hole zone of a formation and a wellbore, comprising introducing into the well through a tubing an aqueous solution of GOS containing ammonium salts of organic or inorganic acids, followed by introducing at least one agent initiating an exothermic reaction into the GOS: alkali metal hypochlorites, nitrous acid salts , while the introduction of the initiator and GOS is carried out separately: GOS is fed through the tubing to the perforated zone, and the combustion initiator is fed into the zone of the GOS through the annulus space of the tubing and the casing (RU 2102589 C1, E 21 B 43/25, 1998). Separate introduction of GOS through the tubing into the treated space of the well, and the initiator of thermochemical treatment along the annulus and mixing them in the region of the perforation interval often leads to damage to the equipment and the outer surface of the tubing, which limits the life of the latter.

There is a method of increasing the productivity of an oil well, including loading through a tubing into the area of perforation of a combustible oxidizing composition from a mixture of nitrate and charcoal, then introducing a combustion initiator from a mixture of magnesium and hydrochloric acid into it, initiating a combustion reaction and after its completion to restore hydrodynamic connection of the well with the formation, subsequent processing by the wellbore of the zone with a saturated solution of nitrate (RU 2100584 C1, E 21 B 43/25, 1997). As a device for introducing reagents into the treated zone in the known method using a tubing, which is placed in the casing of the well, perforated in the interval. GOS and the initiator are loaded so that the upper level of the loaded mixture is not higher than the level of the holes in the perforation interval.

The known invention is directed to the processing of the perforated interval of the borehole (bottomhole) zone of an oil reservoir and solves the problem of increasing the efficiency of oil recovery by restoring oil inflow from oil rims without the formation of permeable main fractures in the area of oil and gas and oil contacts. However, the high content of nitrate in the composition of GOS limits the use of the method and classifies it as unsafe.

A device for treating wells is known, comprising a string of pipes lowered into a well, which provides an impact on the bottomhole formation zone by injecting two reagents through it into the well, resulting in a copious gas evolution between which the main pipe is divided along its entire length into two vertical compartments filled with reagents, and the volumes of the compartments are proportional to the volumes of the reactants that enter into the reaction, and each compartment has a working valve in the lower part, connected by a channel to the mixer the chamber, which is placed in a foam chamber having an outlet opening blocked by a vibrator valve, providing an outlet opening with a predetermined frequency, a pressure generation compartment with a controlled valve or a slowly burning powder charge with an electric igniter is placed in the upper part of the pipe string (RU 2148162 C1, E 21 B 43/25, 04/27/2000).

For complex wells, treatment is repeated.

A disadvantage of the known device is its limited use for the treatment of complex, highly stained wells. The presence of a cable for lowering the tubing can lead to emergency situations, complicates and reduces the safety of the process. But the most significant drawback is that the device can not be used for thermochemical treatment of oil reservoirs using energy-intensive compositions of GOS and combustion initiators.

The closest in technical essence to the claimed invention is a method of thermochemical treatment of a productive formation and a fuel-oxidative composition for its implementation (RU 2153065, E 21 B 43/24, 2000). The method includes injecting into the treatment zone GOS containing in wt.%: A complex compound of oxalic acid diamide and nitric acid 18-36; salicylic acid acetic ester 4-5; potassium permanganate 0,01-0,05, isopropylborane 5-15, water 9-18 and nitrate (ammonia) 21 - 63, then delivery to the zone of GOS location of the combustion initiator, which is used as a composition based on alkali metal borohydride and methanol or diethyl ether in an amount of 5-95 wt.%, or alkali in an amount of 5-25 wt.%, and / or solid isopropylcarborane in an amount of 5-40 wt.%, while GOS and the initiator are served separately. The combustion initiator delivery mechanism to the GOS location zone is carried out in two ways. The first way is in the container with the help of a fishing winch, followed by the destruction of the container by the explosion of a cord torpedo mounted along the entire length of the container. An explosion is initiated by the contact occurrence during the descent of the container between the contacts of the cord torpedo and the source of electricity (battery) installed in the tubing shoe. This initiator delivery method is unsafe due to a possible failure of a torpedo explosion. In addition, this initiator delivery method alone requires sophisticated equipment.

The second way of delivery of the initiator, which is in a liquid state, is to pump it through the lower part of the tubing string, which is equipped with aluminum pipes - a shank, the length of which must exceed the perforation interval of the treated formation.

The closest technical solution to the one claimed in the device part is the second variant of initiator injection into the GOS location zone from RU 2153065, Е 21 В 43/24, 2000. The device for thermochemical processing of a productive formation described in this patent contains a string run into the well through a casing tubing, in which the lower main pipe is equipped with the possibility of separate feed GOS and initiator through the shanks.

The objective of the invention in terms of the device is to expand the type of device for processing the reservoir, its capabilities due to the supply of both solid and liquid reagents, and the possibility of using energy-intensive compositions GOS and initiators.

An object of the invention in terms of the method is the expansion of technological capabilities with a high degree of efficiency of well treatment.

Another objective of the invention is the creation of a new type of tubing device, which allows to increase process safety and to process the formation in any part of it (in the field of perforation, bottom-hole zone, sump) and at any depths.

The technical problem is achieved by the fact that the method of thermochemical treatment of the reservoir, including the injection into the treatment zone through a tubing of a combustible oxidizing composition containing a complex organic compound with nitric acid, nitrate and water, delivering a combustion initiator to the location of the combustible oxidative composition, in this case, 50-82 wt.% ethanolamine nitrate is introduced into the fuel-oxidative composition as a complex compound, and 10 - 50% by weight of the fuel-oxidize is introduced as a combustion initiator nogo at least one of the compounds selected from the series of alkali hydrides and / or alkaline earth metal, or nitrites of said metals. The hydrides of these metals are used in the form of compressed tablets coated with paraffin or rosin. At least one of the series is used as hydrides: lithium, sodium, potassium, calcium hydride, and at least one of the series is used as nitrite: sodium, potassium or calcium nitrite in the form of an aqueous, predominantly saturated solution.

The claimed method for supplying GOS and a combustion initiator using the claimed tubing device allows the formation to be processed in any part of it: in the bottomhole zone, in the region above the perforation interval and in the sump, i.e. in the volume of the reservoir itself.

The use of low toxic ethanolamine nitrate in the composition of GOS allows to reduce the content of nitrate to 5-20 wt.%, Which increases the safety of using GOS and the method as a whole.

A distinctive feature of GOS is its intense gas evolution, the composition of the gases emitted during well treatment, increased technological reliability, convenience and safety of working with GOS.

For the preparation of GOS, reagents of any purity qualification can be used, with the exception of dilute aqueous solutions.

An important feature of the composition is low corrosion activity.

During the combustion of GOS, the main gases emitted are hydrogen, carbon monoxide and nitrogen, i.e. gas mixture, similar in composition to synthesis gas. The addition of nitrate in an amount of not more than 20 wt.%: Ammonia, potassium or sodium, mainly ammonia, increases the performance of the oxidizing agent in the composition of GOS.

Receive GOS either directly at the well, or at enterprises as follows. The required amount of nitric acid is added to the calculated amount of ethanolamine, so that after the reaction, the mixture of components has a pH of not higher than 5. When mixing the components, a large amount of heat is generated, so it is necessary to provide cooling of the container in which the mixing takes place. After cooling the mixture, nitrate is introduced into it and the components are mixed again, cooled and used as intended. The resulting GOS solution is a liquid whose solidification temperature is about minus 30 ° C, which allows the composition to be pumped into wells in the winter season.

It is optimal to prepare GOS and the initiator in stationary specially equipped conditions with their subsequent transportation to the place of use, which excludes the implementation of chemical operations by unskilled personnel near the wells.

The table shows some of the used combustible oxidizing compounds and initiator.

GOS and the combustion initiator can be used to treat wells of various depths, from shallow (500 m) to deep (4000 m), and at any time of the year.

A device for implementing the method of thermochemical treatment of a productive formation containing a tubing string lowered into the well through a casing, providing an impact on the treated zone of the formation by injecting two reagents through the main — first — pipe into the well, while the lower main pipe is made composite with the possibility of separating the reagents while the reagents in the device are divided among themselves by means of two additional pipes installed coaxially one in the other and coaxially with the main one, with a diameter of Rhenney - second - pipes equal to the diameter of the main pipe, while all three pipes are hermetically connected by a connecting device, forming in the inner part of the pipes a free sealed space for the outflow of one of the reagents - combustible-oxidizing composition - from the compartment of the main pipe into the annular space of the second and a third pipe, while the compartment in which the combustible-oxidizing composition is placed is bounded above and below by bypass devices, between which a shear pin is fitted that fits snugly against the sealing plug, and in the compartment located in the volume of the second pipe and in which the second reagent - the initiator of combustion, is located, a shear pin is fitted on top, which is tightly adjacent to the sealing plug, and from below, a sealing plug and a shear pin, which is adjacent to the non-return valve, seal both pipes from the possibility of getting the borehole fluid into the pipe volume.

The device may further comprise a packer, which is installed between the casing and the main pipe.

A schematic diagram of the proposed device is shown in the drawing.

The device for processing the reservoir contains the main - the first - pipe 1, two additional pipes 2 and 3, installed coaxially one in the other and coaxially with the main, with an inner diameter - the second - pipe 2, equal to the diameter of the main pipe 1, while all three pipes are tightly interconnected by a connecting device 4, forming in the inner part of the pipes a free airtight space 5 for the outflow of one of the reagents - combustible-oxidizing composition - from the compartment 6, located in the volume of the main pipe 1, into the annular space thy 7 of the second and third pipes (in the drawing the GOS passage is shown by an arrow), while the compartment 6, in which the GOS is located, is bounded above and below by bypass devices 8 and 9, respectively, between which a shear pin 10 is installed, which is tightly adjacent to the sealing plug 11, in the compartment 12, located in the volume of the second pipe 2 and in which the second reagent, the initiator of combustion, is placed, a shear pin 13 is installed on top, which is tightly adjacent to the sealing plug 14, and from below is a sealing plug 15 and a shear pin 16, which is tightly adjacent to the back mu valve 17 which seals the two pipes of the possibilities falling within the scope of the wellbore fluid pipe.

The device may further comprise a packer 18 mounted between the casing 19 and the main 1 pipes.

The device operates as follows. The device is assembled on the ground, and then lowered through the casing 19 into the formation treatment zone (bottomhole zone, into the formation zone - sump, etc.).

In the free volume of the columns of the pipe 1, a squeezing liquid is pumped under pressure (not shown in the drawing), which, passing through the bypass device 8, breaks the shear pin 10 and the sealing plug 11, while the combustible-oxidizing composition from compartment 6 through the bypass device 9 is completely or partly enters the space 5 (shown in the drawing by arrows), and then into the annular space 7 between the pipes 2 and 3 and then through the check valve 17 passes into the treated zone of the formation. At the same time, under the influence of the squeezing fluid, the shear pin 13 and the sealing plug 14 in the pipe 2 are broken off, after which the combustion initiator from the compartment 12 under pressure breaks the sealing plug 15, the pin 16 and through the check valve 17 enters the treated zone of the oil reservoir. In this case, the time of the initiator's arrival to the GOS location zone can be adjusted depending on the task being solved: the feed can be carried out almost simultaneously with the GOS or with the necessary time delay.

For processing the reservoir using the claimed device, the reagents presented in the table were used.

As a result of the chemical interaction of the reagents in the treated zone, intense gas evolution and temperature increase in the treatment zone above 300 ° C occur, which leads to the dissolution of asphalt-tar deposits and the restoration of the well with the fluid-containing layer of the formation.

As a result of processing in the reservoir, the pressure rises above atmospheric, the fluid (oil) enters the annulus 19 — casing 1 — pipe 1, and then out. In the event that you want to close the well for the required time, put the packer 18 between the casing 19 and the main 1 pipes.

The proposed device is simple to use, using the proposed method can be used to increase the productivity of working wells, to resume abandoned wells of any degree of complexity and depth, can improve the safety of work in the wells when using GOS and initiators with high energy. The device allows you to feed into the treated zone of the reservoir the entire volume of GOS and the initiator of combustion simultaneously or in parts, for this purpose, for example, for supplying GOS, the bypass device 9 is used.

The design of the proposed device allows the use of GOS and the compositions of the initiators in a liquid or solid state, reduces their consumption, improves the efficiency and safety of well treatment, and processes both oil and gas condensate reservoirs.

Claims (6)

1. The method of thermochemical treatment of the reservoir, including the injection into the treatment zone through a tubing of a fuel-oxidative composition containing a complex organic compound with nitric acid, nitrate and water, delivery to the zone of location of the fuel-oxidative composition of the combustion initiator, characterized in that 50-82 wt.% ethanolamine nitrate is introduced into the fuel-oxidative composition as a complex compound, and at least one 50 - 50% by weight of the fuel-oxidative fuel is introduced as a combustion initiator one of the compounds selected from a series of hydrides of alkali and / or alkaline earth metal, or nitrites of these metals. 2. The method according to claim 1, characterized in that the hydrides of these metals are used in the form of compressed tablets coated with paraffin or rosin. 3. The method according to claim 2, characterized in that at least one of a number of hydrides is used as hydrides: lithium, sodium, potassium, calcium hydride. 4. The method according to claim 1, characterized in that at least one of the series is used as nitrite: sodium or calcium nitrite in the form of an aqueous, mainly saturated solution. 5. A device for thermochemical processing of a productive formation containing a tubing string lowered into the well through a casing, providing an impact on the treated zone of the formation by injecting two reagents through the main-first pipe into the well, the lower main pipe being made with the possibility of separation of reagents, characterized in that the reagents in the device are separated by two additional pipes installed coaxially one in the other and coaxially with the main one, with with the diameter of the inner-second pipe equal to the diameter of the main pipe, while all three pipes are hermetically connected by a connecting device, forming a free airtight space in the inner part of the pipe, for the outflow of one of the reagents - the fuel-oxidative composition from the compartment of the main pipe into the annulus of the second and a third pipe, while the compartment in which the combustible-oxidizing composition is placed is bounded above and below by bypass devices, between which a shear pin is fitted that fits snugly a sealing plug, and in the compartment located in the volume of the second pipe and in which the second reagent - the initiator of combustion, is located, a shear pin is fitted on top, which is tightly adjacent to the sealing plug, and from below is a sealing plug and a shear pin, which is adjacent to the non-return valve, seal both pipes from the possibility of getting the borehole fluid into the pipe volume. 6. The device according to p. 5, characterized in that it further comprises a packer installed between the casing and the main pipe.

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