RU2723249C1 - Borehole formation treatment device - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry, namely to the field of pulse technologies of oil production intensification and designs of devices for their implementation. Proposed device comprises charge assembly. Assemblage of charges consists of sequentially arranged head, adapter, two groups of charges, pipe with tip. Head is connected to the cable head, in the inner hole of which the braid is fixed to the geophysical cable by means of the fixing tape. Entire assembly is strung on the braid and fixed thereon. First group includes active charges with volume and dynamics of gas release during combustion, providing creation of pressure pulse in the well with value exceeding mine pressure. Second group consists of main charges with lower dynamics and high volume of gas release in comparison with charges of the first group. It provides creation of secondary pressure front, pulse of which exceeds time of first pressure pulse action. In central axial hole between the charges in each of groups, as well as between the first and the second groups of charges there are split centering bushings. They center charges between groups and group charges relative to each other. Between the first and second groups of charges there is a centraliser holding the second group of charges at a given distance from the first group. This distance is defined by analytical expression.

EFFECT: higher reliability and efficiency of the device, increased number of cracks of the required size in the formation.

3 cl, 6 dwg

Description

The invention relates to the oil industry, and in particular to the field of pulsed technologies for intensifying oil production and device designs for their implementation.

Recently, devices are widely used that provide the formation of a pressure impulse with a high loading rate of the rocks with the formation in the near-well and remote zone of the formation of numerous extended and branched cracks that do not close after unloading. In this case, the gas generator includes an assembly of charges, means for igniting the charges (detonating cord for the first group of charges and a flame-retardant cord for the second group of charges), as well as a load-carrying cable for delivering the gas generator to the well and the mount of the gas generator to the load-carrying cable. The assembly includes the first group of charges with the volume and dynamics of gas evolution during combustion, which ensures the generation of a pressure pulse in the well greater than the rock pressure at a high rate of rise of the pressure pulse. The second group of charges with less dynamics and a large volume of gas evolution (compared with the charges of the first group) provides the creation of a secondary pressure front with a value of at least 0.7 of the value of the first pressure pulse for a time exceeding the duration of the first pressure pulse by 3-15 times ( analogue - RF Patent №2242600, IPC E21B 43/263 (2000.01), 2004).

The disadvantage of this device is the high probability of the displacement of the charges of the second (upper) group relative to each other and relative to the load-bearing cable after the first (lower) group of charges is activated, since both groups of charges are fixed on the cable (cable) by one device located in the lower part of the assembly and the combustion of the lower charges the upper ones lose their support. There is a high probability of damage to generator parts up to the breakage of the carrier cable (spit), on which the entire assembly of the generator is fixed, since at the moment the generator is triggered, the cable is directly affected by the high-temperature combustion products of the powder charges, and then it is rapidly cooled by the borehole fluid, which leads to additional hardening of the steel armor of the cable, which is brittle, breaks when bent and, in turn, leads to a break in the braid and leaving generator parts in the well, which is undesirable, and in most cases, unacceptable. The design of gas generators does not provide for an optimal time delay between the operation of the first group of charges and the start of work of the second group of charges. Because of this, crumbling pieces of rock do not have time to fall into cracks formed after the work of the first group of charges. As a result, expanding cracks partially collapse after the work of the second group of charges.

Known gas generator for degassing a coal seam, including armored and unarmored tubular charges of solid fuel, placed on a geophysical cable, a detonation ignition device containing an explosive cartridge and a detonating cord, characterized in that the detonation ignition device is placed in the channels of the second armor from the second bottom and bottom charges, and in the channel of the lower armored charge a fire ignition device is installed in the form of an electric igniter connected in series with an explosive cartridge at a predetermined distance from it, while the lower end of the gas generator is hermetically sealed with a plug, and the cable has a fireproof coating that protects it from thermal effects of products burning charges (analogue - patent RU 2401385, IPC E21F 7/00 (2006.01), E21B 43/263 (2006.01) from 2010)

The design of gas generators does not provide for the fixing (centering) of charges relative to each other, as a result of which the transfer of combustion from charge to charge does not occur uniformly, which is why the required pressure value of the second group of charges is not always achieved. Another disadvantage of the lack of fixation is damage to the charges during the descent, as the displaced charges are caught by the protruding parts of the casing couplings during descent, and since the damaged charge cannot be worked out according to its parameters, the operation of the gas generator as a whole is disrupted and the efficiency decreases. The design of gas generators does not provide for an optimal time delay between the operation of the first group of charges and the start of work of the second group of charges. Because of this, crumbling pieces of rock do not have time to fall into cracks formed after the work of the first group of charges. As a result, expanding cracks partially collapse after the work of the second group of charges.

A device for processing the borehole zone of the formation, including the assembly of charges and a means of ignition of charges, mounted on a cable, a geophysical cable for lowering the device into the well, wherein the assembly of charges contains the first group of charges with the volume and dynamics of gas evolution during combustion, providing a pressure pulse in the well a value exceeding the rock pressure, and the second group of charges with less dynamics and a large amount of gas in comparison with the charges of the first group, providing a secondary pressure front, the pulse of which exceeds the duration of the first pressure pulse, characterized in that, in order to increase reliability and efficiency processing of the borehole zone of the formation and the safety of handling the device, the second (upper) group of charges has a separate latch, eliminating the movement of charges after the charges of the first (lower) group are triggered (analogue to RU 172681, IPC E21B 43/248 (2006.01), 2016) .

The disadvantage of this solution is the inadequate protection of the spit core and detonating cord, which can lead to failure of the gas generator. The problem of grabbing the geophysical cable is not solved - tossing the geophysical cable upward under the action of the force of the gas generated by the gas generator and entangling the geophysical cable in the nodes and its jamming in the well. In addition, the disadvantage is not the optimal time delay between the operation of the first group of charges and the start of the second group of charges, due to the fact that this gap is provided only by making holes in the latch. Because of what, into the cracks formed after the work of the first group of charges do not have time to fill up with crumbling pieces of rock. As a result, expanding cracks partially collapse back during the work of the second group of charges.

A device for processing the borehole zone of the formation, including the assembly of charges and a means of ignition of charges, mounted on a cable (spit) and a geophysical cable for lowering the device into the well. The charge assembly contains the first group of charges with the volume and dynamics of gas evolution during combustion, providing a pressure pulse in the well of a magnitude higher than the rock pressure, and the second group of charges with lower dynamics and large volume of gas evolution in comparison with the charges of the first group, which create the secondary pressure front, whose pulse exceeds the duration of the first pressure pulse. The cable (braid) on which the charges and generator parts are attached has a protective coating of material with low thermal conductivity, and the head located in the upper part of the assembly has discharge grooves (see patent RU 174107, IPC E21B 43/263 (2006.01), E21B 23/08 (2006.01), 2017). This decision was made as a prototype.

The design of the device does not provide for the fixation (centering) of charges relative to each other, as a result of which the transfer of combustion from charge to charge does not occur uniformly, which is why the required pressure value of the second group of charges is not always achieved. Another disadvantage of the lack of fixation and, as a consequence, the displacement of charges is damage to the charges during descent, because the displaced charges engage in protruding parts over the casing collars during descent. Since the damaged charge cannot work out according to its parameters, the operation of the gas generator as a whole is disrupted and the efficiency decreases. The problem of protection from interruption during the explosion of charges of the bent part of the cable passing through the tip is not solved. As a result of such an interruption, all charges that are held on the streamer are dumped from it to the bottom of the well and the operation of the gas generator is useless. The optimal dose of supply of combustion products to the second group of charges is not provided, which does not provide the necessary time interval between the operation of the groups of charges.

The technical problem solved by the invention is to increase the reliability and efficiency of processing the borehole zone of the formation.

The technical problem is solved due to the fact that in the known device for processing the borehole zone of the formation, containing an assembly of charges mounted on a spit and consisting of a consecutive head, two groups of charges, a pipe with a tip, including a means of ignition of charges and provided with openings for the exit of combustion products charges, in which the streamer has a protective coating of a material with low thermal conductivity, the first group includes active charges with the volume and dynamics of gas evolution during combustion, providing a pressure pulse in the borehole with a value exceeding the rock pressure, and the second group consists of main charges with lower dynamics and a large volume of gas evolution in comparison with the charges of the first group, providing the creation of a secondary pressure front, the pulse of which exceeds the duration of the first pressure pulse, in accordance with the invention, the charge assembly is equipped with split centering sleeves located between the charges in the central axial hole, a centralizer that holds the second group of charges at a distance δ from the first, and an adapter with holes for the exit of the products of combustion of charges installed therein, installed between the head and the second group of main charges, and the tip is equipped with a cover and a second hole offset from the axis symmetry and host streamer.

The distance between groups of charges δ is determined by the formula:

δ = K * S1 / S2, where

; K - experimental coefficient

;

S1 - contact end area of the first group of (active) charges

S2 is the maximum end contact area of the second group of (main) charges.

The upper part of the adapter is made conical.

The braid is fixed in the tip with three fixing screws.

The technical result from the use of all the essential features of the invention is to increase the reliability and efficiency of the device, to ensure that a large number of cracks of the required size are obtained in the rock.

A device in which the charge assembly is equipped with split centering sleeves located between the charges in the central axial hole, a centralizer holding the second group of charges at a distance δ from the first, and an adapter with openings made therein for the exit of the products of combustion of charges installed between the head and the second a group of main charges, and the tip is equipped with a cap and a second hole offset from the axis of symmetry and receiving the spit core, which allows to increase the reliability and efficiency of the device.

The presence of split centering sleeves allows not only to preserve the integrity of the charge groups during transportation of the device to the activation site, but also to increase the uniformity of their work, which increases the efficiency of creating a pressure pulse. Since the contact area of the charges with each other increases, the efficiency of the transfer of combustion from charge to charge increases. Due to the elasticity of the walls of the split centering sleeves, it is also possible to mount charge groups and fix charge groups to each other.

The presence of a centralizer, which ensures the location of two groups of charges (active and main) at a distance δ from each other, allows you to create the necessary time interval between the operation of the active and main charges and deliver the optimal dose of combustion products of active charges to the main charges, which increases the reliability and efficiency devices. Due to this time interval, crumbling pieces of rock appear in the cracks, which are pushed by the gases released from the work of the charges and hold the cracks in the open state by these pieces of rock and prevent them from closing back.

The implementation of the adapter with openings for the exit of the products of combustion of charges, provides a directed exit of the products of combustion of charges, so that the entire assembly of charges appears pulling down force. This helps to prevent sticking (twisting and bending) of the geophysical cable on which the device is lowered, which ensures increased reliability of the device and reduced accident rate.

The cover that covers the bottom of the tip eliminates damage to the braid carrying the assembly, and the strand of the braid passing to the electric detonator during transportation of the device and the triggering of charges.

The execution of the tip with a second hole, offset from the axis of symmetry and receiving the spit core, eliminates damage to the spit core, which transmits an electrical impulse to the electric detonator, during the transportation and operation of charges.

In FIG. 1 - general view of the device;

FIG. 2 is a view A of FIG. 1 (enlarged image of the tip, a hole for the core displaced from the axis of symmetry is shown);

FIG. 3 - section aa of fig 1;

FIG. 4 is a view B of FIG. 1;

FIG. 5 - centering sleeve;

FIG. 6 - centralizer.

To transport the device to the activation site in the well, a cable head 1 and a geophysical cable 2 are attached to it.

A device for processing the borehole zone of the reservoir contains an assembly of charges, consisting of the following elements:

Head,

Scythe

Clamping screw

Adapter,

Main charges (second group of charges),

Split centering sleeves,

Centralizer

Active charges (first group of charges),

Lower centralizer

Detonating cord

Trumpet,

Electric detonator,

Tip,

Tip cap

Lived braids.

All elements included in the charge assembly are mounted on the spit 5, the outer armor of which is composite - mixed with a polymer having low thermal conductivity.

The charge assembly consists of a sequentially located head 4, adapter 7, two groups of charges 8, 11, pipe 14 with a tip 16 (see Fig. 1). The head 4 is connected to the cable head 1, in the inner hole of which the braid 5 is fastened with a geophysical cable 2 using the fixing tape 3. The whole assembly is strung on the braid 5 and held by fixing the ferrule 16 and head 4 on the braid 5 using clamping screws 6. Thus Thus, the assembly remains rigid and charges 11 and 8 do not move along the streamer 5 during the descent of the device into the well (see Fig. 1).

The first group 11 includes active charges with the volume and dynamics of gas evolution during combustion, ensuring the creation of a pressure pulse in the well with a value exceeding the rock pressure. The second group 8 consists of the main charges with less dynamics and a large volume of gas evolution in comparison with the charges of the first group, providing the creation of a secondary pressure front, the pulse of which exceeds the duration of the first pressure pulse. The number of charges in each group can vary (on average 10-15 charges).

In the central axial hole 19 between the charges in each of the groups, as well as between the first 11 and second 8 groups of charges, split centering sleeves 9 are installed (see Figs. 1, 3, 5), centering the charges in the groups and the charges of the groups 8 and 11 relative to each other. Split centering bushings 9 are made elastic and can be made of plastic or corrosion-resistant aluminum alloys. Split centering sleeves 9, which center the charges relative to each other, can increase the uniformity of the charges and increase the efficiency of creating a pressure pulse. Since the area of contact between the charges with each other in each group, as well as the charges of the groups increases, the efficiency of the transfer of combustion from charge to charge and from charges of the first group 11 to the charges of the second group 8 increases. In addition, the presence of split centering sleeves 9 ensures the integrity of the charges during descent, since they do not allow the charges to move relative to each other, which increases the reliability of the device.

Between the first 11 and second 8 groups of charges is a centralizer 10, which holds the second group of 8 charges at a distance δ from the first group 11 (see Fig. 4, 6).

It was experimentally established that the optimal distance δ between the active 11 and the main 8 charges obeys the following dependence:

δ = K * S1 / S2,

Where K is the experimental coefficient, equal to 1.2≤K≤5. The magnitude of the coefficient depends on the power and the number of charges.

S1 - contact end area of the first group of 11 active charges

S2 is the maximum end contact area of the second group of 8 main charges.

There are no centralizers or gaps between the main charges in group 8 and between the active charges in group 11. A tight fit and centering of the charges in groups is ensured by split centering sleeves 9. The sleeves 9 are also installed between the groups of charges 8 and 11.

An adapter 7 is mounted between the head 4 and the second group 8 of the main charges, rigidly connected to the head 4. The lower part 20 of the adapter 7 enters the axial hole 19 of the second group 8 of the main charges and holds it due to the tight fit (see Fig. 1). The upper part of the adapter 7 has a conical shape, and the diameter of the lower part corresponds to the size of the main charges of the second group 8. By making the upper part of the adapter 7 conical, it becomes possible to connect the charges of group 8 with the same unified head 4, which can have different diameters in depending on the required conditions. The conical shape of the adapter thus contributes to the unhindered passage of charges through the well, which improves the reliability of the device.

In the adapter 7, holes 21 are made (see Fig. 1) for the exit of the products of combustion of charges, so that a pulling force appears in the entire charge assembly during the operation of the device. Due to the rounded shape of the holes 21, the aerodynamics of the gas outlet is improved, which further reduces the magnitude of the axial force directed upward and acting on the head 4. Due to the nozzle effect (outflow of gases from the holes 21 leads to an increase in gas velocity), a reactive force directed downwards , contributing to the straightening of the geophysical cable 2. Which leads to increased reliability and reduced accident rate when using the device.

Below the active charges 11, there is a tube 14, in which the means for igniting the charges, made in the form of an electric detonator 15 connected to the wire 18 of the spit 5, are placed. A detonating cord 13 is laid from the electric detonator 15 to the first group 11 of active charges, providing ignition of the active charges. The detonating cord 13 is fixed on the braid 5 using the fixing tape 3.

The tip 16 has two holes. One hole 19 is axial, designed to power clamp the braid 5, on which the entire assembly is held, with three fixing screws 6, ensuring reliable braid retention.

The second hole 22, made in the tip 16, is offset from the axis of symmetry 23, runs parallel to the axis of symmetry and is intended to lead the core 18 of the braid 5 into the pipe 14. The core 18 of the braid 5 is connected to the electric detonator 15.

For greater reliability, the tip 16 is closed from the bottom by a cover 17, which eliminates damage to the spit core 18. Such placement of the fixation of the spit 5 and ensuring the passage of its core increases the reliability of initiation, eliminating damage to the spit and the spit core 18 during the descent into the well.

A device for processing the borehole zone of the formation works as follows:

From an explosive machine, a geophysical cable 2 is supplied with an electrical impulse, which is transmitted to an electric detonator 15 through a streamer 5 and a strand 18 of a streamer. When triggered, the detonator 15 detonates the cord 13.

From the detonation products of the detonating cord 13, the active charges of the first group 11 are ignited and burn in volume mode, which, when released by gas, create a pressure impulse that exceeds the rock pressure in value. Due to this, cracks form in the bottomhole zone of the formation.

The products of combustion of the active charges of the first group 11 set fire to the main charges of the second group 8, which burn in a layer-by-layer mode, with a lower speed and a large volume of gas evolution compared to the active charges of the first group 11, creating a secondary pressure front. This leads to the fact that the formed cracks lengthen.

The active charges of the first group 11 and the main charges of the second group 8 are separated from each other by the centralizer 10 by a distance δ. The centralizer 10 is designed to provide the optimal dose of supply of combustion products to the main charges and create the necessary time interval between the operation of the first group 11 of active and the second group of 8 main charges. Due to this time interval, crumbling pieces of rock appear in the cracks, which are pushed by the gases released from the work of the main charges, so the cracks are kept open by these pieces of rock and do not close.

In this case, the braid 5 has an outer layer of armor mixed with a polymer (for example, fluoroplast-4), so that the braid 5 retains its strength during the explosive action of the detonating cord 13.

The inventive device for processing the borehole formation zone provides increased reliability and processing efficiency of the borehole formation zone.

The claimed device for processing the borehole zone of the reservoir can be manufactured using existing materials on modern technological equipment.

The device can be used in the field of gas and oil production.

Claims (7)

1. A device for processing the borehole zone of the formation, containing an assembly of charges mounted on a spit and consisting of a sequentially located head, two groups of charges, a pipe with a tip, including means for igniting the charges and provided with openings for the exit of combustion products of charges, in which the spit has a protective coating from a material with low thermal conductivity, the first group includes active charges with the volume and dynamics of gas evolution during combustion, providing a pressure pulse in the well with a value exceeding the rock pressure, and the second group consists of main charges with lower dynamics and a large volume of gas evolution compared to the charges of the first groups providing the creation of a secondary pressure front, the impulse of which exceeds the duration of the first pressure impulse, characterized in that the charge assembly is equipped with split centering sleeves located between the charges in the central axial hole, the centralizer holding the second the first group of charges at a distance of δ from the first, and an adapter with openings for the exit of the products of combustion of charges installed between the head and the second group of main charges, the tip is equipped with a cover and a second hole offset from the axis of symmetry and receiving the strand of the braid, and the distance is δ between groups of charges calculated by the formula: δ = K * S1 / S2, where K - experimental coefficient

S1 is the contact end area of the first group with active charges; S2 is the maximum end contact area of the second group - the main charges. 2. The device according to claim 1, characterized in that the upper part of the adapter is made conical. 3. The device according to claim 1, characterized in that the braid is fixed in the tip with three fixing screws.

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