CN113898330B - An integrated device and method for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells - Google Patents

Abstract

The invention relates to an integrated device and method for methane in-situ perforation and explosion fracturing in the open-hole section of a horizontal well, which includes a combustion accelerant storage tank, a pressurized pumping system, an exhaust gas discharge system, a buffer, an igniter, and a new perforating bomb. , perforation, explosion and fracturing integrated pipe string, centralizer and open hole packer and other system equipment, which can realize in-situ explosion and perforation of methane gas in the open hole section of the target formation and multi-stage repeated explosion and fracturing. The invention realizes the multi-stage repeated fracturing work of the fracturing section without moving the pipe string. After completing the fracturing of this section, the fracturing equipment withdraws from the wellbore, reinstalls the perforating bomb, and repeats the fracturing process in the next fracturing section. The above process realizes staged explosion fracturing of horizontal wells, thereby obtaining a larger-scale diversion fracture network and achieving efficient shale gas exploitation.

Description

An integrated device and method for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells

Technical field

The invention relates to an integrated device and method for methane in-situ perforation and explosion fracturing in the open hole section of a horizontal well, which is suitable for complex tight gas, shale gas and other reservoirs and belongs to the technical field of explosion and fracturing.

Background technique

The national oil and gas resource evaluation results show that my country has quite abundant unconventional oil and gas resources such as tight gas and shale gas. Limited by technology and cost, exploration and development progress has been relatively slow. It was not until recent years, with the advancement and large-scale application of large-scale hydraulic fracturing stimulation technology, that the development of low-porosity and low-permeability reservoirs such as tight gas and shale gas has achieved rapid progress. made progress. However, my country's unconventional oil and gas resources are generally buried deep, and it is difficult to form complex fracture networks under high stress differences and large burial depths. The overall shortage of water resources is also not conducive to the promotion of hydraulic fracturing technology.

Explosive fracturing technology is not limited by water-sensitive and acid-sensitive formations. By generating higher peak pressure and faster impact loading rate, it can form multiple radial fractures that are not controlled by in-situ stress. Even if no proppant is added during the fracturing process, the fractures can remain open under high closing stresses.

The existing explosion fracturing technology mostly uses perforation operations combined with the placement and detonation of explosives to create fractures and connect the wellbore with the reservoir. However, this process requires a large amount of engineering work, the effective time of explosion pressure is short, and fractures are created. The scale is limited. At the same time, the transportation and release of pyrotechnics products also causes greater safety hazards, which is not conducive to on-site promotion and application.

Contents of the invention

Based on the deficiencies of the above-mentioned explosive fracturing technology, the present invention provides an integrated device and method for methane in-situ explosive perforation and fracturing in the open hole section of a horizontal well, using the methane gas desorbed from the reservoir as a combustible material. After the perforation and explosion fracturing string is sent to the target fracturing section, the exhaust gas discharge system and the pressurized pumping system are used to complete the mixing of methane gas storage and combustion accelerant, and then detonated in situ. The high-energy explosion gas cooperates with the new injection system. The hole bomb completes the perforating operation and forms pre-set fractures, and then repeats the process of exhaust gas discharge, introduction of reservoir methane gas, pumping of combustion accelerant, ignition and detonation, and the completion of multi-stage repetition of the fracturing section without moving the pipe string. fracturing work to obtain a larger diversion fracture network and achieve safe and efficient shale gas extraction.

The technical solution of the present invention is as follows:

An integrated device for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells suitable for complex tight gas, shale gas and other reservoirs, including a detonation device and an integrated perforation, combustion and fracturing device connected in sequence;

The detonation device is used to carry the combustion accelerant into the well, control the pumping of the combustion accelerant, and control exhaust gas emissions;

The perforation, explosion and fracturing integrated device is used to complete perforation and fracturing operations in the fracturing section of the target layer.

According to the preferred embodiment of the present invention, the detonation device includes a combustion accelerant storage tank, a pressurized pumping system, an exhaust gas discharge system and an igniter;

The combustion accelerant storage tank is used to carry the combustion accelerant into the well;

One end of the pressurized pumping system is connected to the combustion accelerant storage tank, and the other end is connected to the perforation, explosion and fracturing integrated device, and the pumping of the combustion accelerant is controlled through the pressurized pumping system;

One end of the exhaust gas emission system is connected to the annular space outside the gas discharge ignition column, and the other end is connected to the perforation, explosion and fracturing integrated device, and the exhaust gas emission is controlled through the exhaust gas emission system;

According to the preferred embodiment of the present invention, the pressurized pumping system, the exhaust gas discharge system and the igniter are all integrated in the same gas discharge and ignition pipe column. One end of the gas discharge and ignition pipe column is provided with an internal thread joint, which is connected to the gas discharge and ignition pipe column. The combustion accelerant storage tank is connected, and the other end of the gas discharge and ignition pipe string is provided with an external threaded joint, which is connected to the perforation, explosion and fracturing integrated device.

According to the preferred embodiment of the present invention, the integrated perforating, explosive and fracturing device includes a new type of perforating charge and an integrated perforating, explosive and fracturing string;

The wall of the perforating, explosive and fracturing integrated pipe string is provided with grooves for carrying the new type of perforating bombs and guiding the explosive gas to create directional seams; inside the perforating, explosive and fracturing integrated pipe string The space forms a cavity.

Further preferably, the new type of perforating bomb has holes reserved, and the new type of perforating bomb is equipped with shaped explosives inside.

Further preferably, the hole diameter of the new perforating charge is not less than 5mm.

Further preferably, the groove is a strip groove.

Further preferably, the perforation, explosion and fracturing integrated pipe string has at least two strip grooves in the same circular cross-section, and there are many strip grooves on the wall of the perforation, explosion and fracturing integrated pipe string. in three groups.

According to the preferred embodiment of the present invention, the perforation, explosion and fracturing integrated device further includes a left buffer and a right buffer, and the left buffer and the right buffer are respectively provided at both ends of the perforation, explosion and fracturing integrated pipe string. Describe the right buffer.

According to the preferred embodiment of the present invention, the methane in-situ perforation and explosion fracturing integrated device in the open hole section of the horizontal well also includes a pipe string auxiliary device;

The pipe string auxiliary device includes a left centralizer, a right centralizer, a left open hole packer and a right open hole packer;

The left centralizer is disposed on the combustion accelerant storage tank shell, the right centralizer is disposed at the end of the perforation, combustion and fracturing integrated device; the left open hole packer is located on the gas discharge In the middle of the ignition string, the right open hole packer is located between the right buffer and the right centralizer to separate the annular space of the fracturing section.

According to the preferred embodiment of the present invention, the igniter includes an ignition wire, which is exposed in the inner cavity of the perforation, explosion and fracturing integrated pipe string, and the remaining parts of the igniter are hermetically installed in the gas discharge ignition pipe string. .

Further preferably, the ignition wire is made of high-strength conductive metal materials, including copper-chromium alloy, copper-silver alloy and nanocrystalline copper.

According to the present invention, it is preferred that there are at least two left centralizers and at least one right centralizer.

A perforation fracturing method of an integrated device for methane in-situ perforation and explosion fracturing in the open-hole section of horizontal wells in complex tight gas, shale gas and other reservoirs, including the following steps:

(1) Embed the new perforating bomb into the strip groove of the perforating, explosive and fracturing integrated string, and install the right buffer, left buffer, right open hole packer and right centralizer; then screw them in sequentially gas transfer ignition string with left open hole packer and accelerant storage tank with left centralizer;

(2) Lower the methane in-situ perforation and explosion fracturing integrated device together with the tubing string into the open-hole fracturing section of the target layer of the horizontal well;

(3) After the left and right centralizers control the methane in-situ perforation, explosion and fracturing integrated device in the open hole section of the horizontal well, the left and right open hole packers complete the setting and separation of the open hole section. The annular space on the left and right sides of the naked hole section;

(4) Turn on the exhaust gas discharge system, discharge the gas in the annular space between the left open hole packer and the right open hole packer and the cavity of the perforation, explosion and fracturing integrated string, and the methane gas desorbed from the reservoir will pass through The holes reserved for the new perforating charge enter the cavity;

(5) After the methane gas fills the chamber, close the exhaust gas emission system, turn on the pressurized pumping system, and transport the combustion accelerant into the chamber. After the mixing ratio requirements are met, close the pressurized pumping system;

(6) After the gas storage is completed, the igniter is ignited. On the one hand, the high-temperature and high-pressure detonating gas impacts and burns the reservoir through the holes of the new perforating charge. On the other hand, it bombards the charge cover, causing the shaped explosive to explode and generate a high-speed metal jet. Penetrate the reservoir and coordinate to complete the perforation of the fracturing section;

(7) After completing the perforating operation, the waste gas is discharged, the reservoir methane gas is introduced and the combustion accelerant is pumped in, and then ignited and detonated. The detonating gas is directed through the strip groove to form radial multi-slit three-dimensional fractures in the open hole section of the horizontal well. net;

(8) Repeat step (7), that is, to complete the multi-stage repeated fracturing work of the target layer fracturing section without moving the pipe string, so that the fracture network volume can be expanded;

(9) After completing the fracturing of this section, the methane in-situ perforation and explosion fracturing integrated device in the open hole section of the horizontal well is withdrawn from the wellbore, the new perforating charge is reinstalled, and the perforation and explosion pressure is repeated in the next fracturing section. The process of fracturing realizes staged fracturing.

The beneficial effects of the present invention are:

1. The new technology used in the present invention includes a combustion accelerant storage tank, a pressurized pumping system, an exhaust gas discharge system, a buffer, an igniter, a new perforating charge, an integrated perforating explosion fracturing string, a centralizer and System equipment consisting of open hole packers and other system equipment, using these equipment and the methane gas desorbed in the open hole section to complete perforation and explosion fracturing operations without moving the string, on the one hand, avoiding the ground transportation of explosives during the explosion and fracturing process , underground injection and other processes. On the other hand, the perforation explosion fracturing device and process are optimized. The construction process is safe and environmentally friendly, which can make up for the shortcomings of the existing explosion fracturing technology and is conducive to on-site promotion and application.

2. The combustible material used in this invention is methane gas desorbed in the reservoir. On the one hand, this gas replaces the traditional detonator to detonate the new perforating bomb, and on the other hand, it replaces artificial explosives as the combustible material in the detonation and fracturing process. The construction process is more environmentally friendly and economical.

3. The detonation device used in the present invention, the perforation, explosion and fracturing integrated device and other pipe string connections adopt standardized designs. The pipe strings are connected to the well by threading. The device structure is simple and the design is reasonable. Convenient for construction operations and maintenance.

4. The new perforating charge used in the present invention cooperates with the strip groove to perforate in a directional manner to create fractures, which conforms to the crack initiation law and makes it easier to form a three-dimensional fracture network.

5. The perforation, explosion and fracturing integrated device used in the present invention cooperates with the reservoir methane gas to complete the perforation operation and multiple explosion and fracturing operations without moving the pipe string, which not only simplifies the construction process, but also ensures The effective action time of explosion pressure is shortened, and the scale of joint creation is larger.

6. The open-hole perforation completion method adopted in the present invention can, to a certain extent, make up for the limited fracture-creation capabilities of explosive fracturing, and provides a more reasonable design for the promotion of this process.

Description of the drawings

Figure 1 is a schematic structural diagram of an integrated device for methane in-situ perforation, combustion and fracturing in the open-hole section of a horizontal well.

Figure 2 is a schematic structural diagram of the perforation, explosion and fracturing integrated pipe string.

Figure 3 is a cross-sectional view of the perforating, explosive and fracturing integrated pipe string and new perforating bombs.

1. Combustion aid storage tank; 2. Pressurized pumping system; 3. Exhaust gas emission system; 4. Ignition; 5. Ignition wire; 6-1. Left buffer; 6-2. Right buffer; 7. New type Perforating charge; 8. Integrated perforation, explosion and fracturing string; 9. Containment chamber; 10-1, left centralizer; 10-2, right centralizer; 11-1, left open hole packer; 11- 2. Right open hole packer; 12. Groove; 13. Hole; 14. Shaped explosive; 15. Metal shell; 16. Drug cover.

Detailed ways

The present invention will be further described below through examples and in conjunction with the drawings, but is not limited thereto.

Example 1

An integrated device for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells suitable for complex tight gas, shale gas and other reservoirs, including a detonation device and an integrated perforation, combustion and fracturing device connected in sequence;

The detonation device is used to carry the combustion accelerant into the well, control the pumping of the combustion accelerant, and control the exhaust gas emissions; the perforation, combustion, and fracturing integrated device is used to complete the perforation and fracturing operations of the target layer fracturing section.

The perforating, explosive and fracturing integrated device is used to complete the perforating and fracturing operations in the fracturing section of the target layer. The conventional perforating and fracturing processes and operating equipment are completely independent. On the one hand, this device attributes the two to the same operating pipe. In the column, on the other hand, the unique device structure can effectively utilize the methane gas precipitated from the formation to complete the perforation and fracturing operations, so that the perforation of the fracturing section and multi-stage repeated fracturing can be completed without moving the pipe string. the goal of.

Example 2

An integrated device for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells suitable for complex tight gas, shale gas and other reservoirs according to Embodiment 1. The difference is:

As shown in Figure 1, the detonation device includes an accelerant storage tank 1, a pressurized pumping system 2, an exhaust gas emission system 3 and an igniter 4;

The combustion accelerant storage tank 1 is used to carry a sufficient amount of combustion accelerant into the well; one end of the combustion accelerant storage tank 1 is provided with an internal threaded joint, and the other end, i.e., the outlet end, is provided with an externally threaded joint. The internal threaded joint is connected to a conventional pipe string and is connected through an external thread. The threaded joint connects the gas discharge ignition pipe string.

One end of the pressurized pumping system 2 is connected to the combustion accelerant storage tank 1, and the other end is connected to the perforation, explosion and fracturing integrated device. The pumping of the combustion accelerant is controlled through the pressurized pumping system 2; the pressurized pumping system 2 is used for detection. The mixing ratio of methane gas and combustion accelerant inside the perforation, combustion, explosion and fracturing integrated device controls the pumping amount of accelerant. The pressurized pumping system 2 is proposed based on the purpose of using formation methane gas to complete reservoir explosion fracturing. By cooperating with the combustion accelerant storage tank 1, it can solve the problem of insufficient dosage of combustion accelerant and how the combustion accelerant interacts with it under high formation pressure. The problem of efficient mixing of methane gas.

One end of the exhaust gas discharge system 3 is connected to the annular space outside the gas discharge ignition pipe string. The annular space refers to the annulus between the operation pipe string and the wellbore wall; the other end is connected to the perforation, combustion and fracturing integrated device. Through the exhaust gas discharge system 3. Control exhaust gas emissions; the exhaust gas emission system 3 is used to detect the content of methane gas and combustion exhaust gas inside the perforation, combustion, explosion and fracturing integrated device, and control the discharge of exhaust gas and the filling of methane gas in the perforation, combustion, explosion and fracturing integrated device. The exhaust gas emission system 3 is proposed based on the purpose of using formation methane gas to complete reservoir explosion fracturing. It completes the first exhaust gas emission by cooperating with the reserved hole 13 of the perforating charge, and the methane is filled into the chamber 9 and the explosion perforation is completed. Operation, by matching the strip groove to complete the subsequent multiple exhaust gas emissions, methane charging and explosion fracturing operations.

The pressurized pumping system 2, the exhaust gas discharge system 3 and the igniter 4 are all integrated in the same gas discharge and ignition pipe column. One end of the gas discharge and ignition pipe column is equipped with an internal thread joint and is connected to the combustion accelerant storage tank 1. The gas discharge and ignition pipe column is The other end of the ignition pipe string is equipped with an external threaded joint, which is connected to the perforation, explosion and fracturing integrated device.

The igniter 4 includes an ignition wire 5, which is exposed in the inner cavity 9 of the perforation, explosion and fracturing integrated pipe string 8. The remaining parts of the igniter 4 are hermetically installed in the gas discharge ignition pipe string. The ignition wire 5 is made of high-strength conductive metal materials, including copper-chromium alloy, copper-silver alloy and nanocrystalline copper.

The integrated perforating, explosive and fracturing device includes new perforating charges 7 and an integrated perforating, explosive and fracturing string 8;

As shown in Figure 2, the wall surface of the perforating, explosive and fracturing integrated pipe string 8 is provided with grooves 12, which are used to carry the new perforating bombs 7 and guide the explosive gas to create directional fractures; the perforating, explosive and fracturing integrated pipe string The space within the tubular column 8 forms a cavity 9 .

As shown in Figure 3, the new perforating charge 7 has reserved holes 13. The new perforating charge 7 is equipped with a shaped charge 14 inside. The shaped charge 14 is set in the charge cover 16. The shell of the new perforating charge 7 is made of metal. Shell 15.

The hole diameter of the hole 13 of the new perforating charge 7 is not less than 5mm.

Groove 12 is a strip groove. On the one hand, the strip grooves can be loaded with multiple perforating charges with square bases; on the other hand, the multiple strip grooves can induce high-energy detonation gas to create directional fractures to form a radial multi-fracture network.

The perforating, explosive and fracturing integrated pipe string 8 has at least two strip grooves in the same circular cross-section, and the wall surface of the perforating, explosive and fracturing integrated pipe string 8 has no less than three groups of strip grooves.

The perforation, explosion and fracturing integrated device also includes a left buffer 6-1 and a right buffer 6-2. The two ends of the perforation, explosion and fracturing integrated pipe string 8 are respectively provided with a left buffer 6-1 and a right buffer. Buffer 6-2. It can slow down the severe axial vibration of the perforating, blasting and fracturing integrated pipe string 8.

Example 3

According to Embodiment 2, an integrated device for methane in-situ perforation, combustion and fracturing in the open-hole section of horizontal wells suitable for complex tight gas, shale gas and other reservoirs has the following differences:

The integrated device for methane in-situ perforation, explosion and fracturing in the open-hole section of horizontal wells also includes a pipe string auxiliary device;

The pipe string auxiliary devices include left centralizer 10-1, right centralizer 10-2, left open hole packer 11-1 and right open hole packer 11-2;

The left centralizer 10-1 is installed on the shell of the combustion accelerant storage tank 1, and the right centralizer 10-2 is installed at the end of the perforation, explosion and fracturing integrated device; in a horizontal well, the operating pipe string will interact with the well due to the influence of gravity. Wall friction may cause damage to the operating pipe string and the wellbore. To ensure that the operating pipe string can reach the target layer smoothly and operate normally, a left centralizer 10-1 and a right centralizer 10-2 need to be installed before going down the well.

The left open hole packer 11-1 is located in the middle of the gas discharge ignition string, the right open hole packer 11-2 is located between the right buffer 6-2 and the right centralizer 10-2, and the right open hole packer 11-2 Located 0.5m from the right end of the right buffer 6-2, it is used to separate the annular space of the fracturing section.

There are at least two left centralizers 10-1 and at least one right centralizer 10-2.

Example 4

The perforation fracturing method described in Embodiment 3, which is suitable for the methane in-situ perforation and explosion fracturing integrated device in the open hole section of horizontal wells in complex tight gas, shale gas and other reservoirs, includes the following steps:

(1) Embed the new perforating charge 7 into the strip groove of the perforating, explosive and fracturing integrated string 8, and install the right buffer 6-2, the left buffer 6-1, and the right open hole packer 11 -2 and the right centralizer 10-2; then screw in the gas discharge ignition string with the left open hole packer 11-1 and the combustion accelerant storage tank 1 with the left centralizer 10-1;

(2) Lower the methane in-situ perforation and explosion fracturing integrated device together with the tubing string into the open-hole fracturing section of the target layer of the horizontal well;

(3) After the left centralizer 10-1 and the right centralizer 10-2 control the methane in-situ perforation and explosion fracturing integrated device in the open hole section of the horizontal well, the left open hole packer 11-1 and the right open hole seal The spacer 11-2 completes the setting of the open hole section and separates the annular space on the left and right of the open hole section;

(4) Open the exhaust gas discharge system 3, and discharge the gas in the annular space between the left open hole packer 11-1 and the right open hole packer 11-2 and the cavity 9 of the perforation, explosion and fracturing integrated string 8 The methane gas desorbed from the reservoir enters the cavity 9 through the holes 13 reserved for the new perforating charge 7;

(5) After the methane gas fills the chamber 9, close the exhaust gas emission system 3, turn on the pressurized pumping system 2, and transport the combustion accelerant into the chamber 9. After the mixing ratio requirements are met, the gas mixing ratio requirements are based on the type of combustion accelerant. and reservoir methane content and other factors, it can meet the needs of fracture reconstruction scale. The specific mixing ratio is determined according to the actual situation, and the pressurized pumping system 2 is turned off;

(6) After the gas storage is completed, the igniter 4 is ignited. On the one hand, the high-temperature and high-pressure detonation gas impacts and burns the reservoir through the holes 13 of the new perforating charge 7. On the other hand, it bombards the charge cover 16, causing the shaped explosive 14 to explode. Generate high-speed metal jets, penetrate the reservoir, and coordinate to complete the perforation of the fracturing section;

(7) After completing the perforating operation, the waste gas is discharged, the reservoir methane gas is introduced and the combustion accelerant is pumped in, and then ignited and detonated. The detonating gas is directed through the strip groove to form radial multi-slit three-dimensional fractures in the open hole section of the horizontal well. net;

(8) Repeat step (7), that is, to complete the multi-stage repeated fracturing work of the target layer fracturing section without moving the pipe string, so that the fracture network volume can be expanded;

(9) After completing the fracturing of this section, the methane in-situ perforation, explosion and fracturing integrated device in the open hole section of the horizontal well is withdrawn from the wellbore, the new perforating charge 7 is reinstalled, and the perforation and explosion is repeated in the next fracturing section. The process of fracturing realizes staged fracturing.

After the methane in-situ perforation and explosion fracturing of the open-hole section of the horizontal well is completed, the operating string is withdrawn and the wellbore is cleaned to evaluate the construction effect.

In this example, the well depth of the target layer is 2000m, the formation fracture pressure is 43MPa, the length of the open hole section is 10m, and the average well diameter of the open hole section is 152.4mm.

In this embodiment, individual device dimensions: the outer diameter of the oil pipe is 114.3mm; the detonation device is 3m long, the outer diameter is 114.3mm, and the wall thickness is 6.88mm; the combustion accelerant storage tank 1 is 2m long; the perforation, explosion and fracturing integrated pipe string is 8 long 6m, outer diameter 120mm, wall thickness 25mm; strip groove length 1m, width 25mm; new perforating charge 7 center aperture 6mm, bottom size 25×25mm, height 25mm.

In this embodiment, the combustible material used is methane gas desorbed in the reservoir. On the one hand, this gas replaces the traditional detonator to detonate the new perforating charge 7, and on the other hand, it replaces artificial explosives and serves as the combustible gas in the detonation and fracturing process. It effectively avoids the application of pyrotechnics products, and the construction process is safer and more economical; the detonation device and the perforation, explosion and fracturing integrated device adopt a standardized design and are connected to the well by threading, which facilitates construction operations and repeated maintenance. Use; the perforation, explosion and fracturing integrated device selects the perforation, explosion and fracturing integrated pipe string 8 with three rows of grooves 12 for joint creation according to the construction requirements, one row of grooves 12 has three strip grooves ; Using these equipment and the methane gas desorbed in the open hole section, perforating operations and multiple explosion fracturing can be completed without moving the pipe string, which not only simplifies the construction process, but also ensures the effective action time of explosion pressure and creates joints. On a larger scale.

Example 5

According to the perforation and fracturing method of the methane in-situ perforation and explosion fracturing integrated device in the open-hole section of horizontal wells in complex tight gas, shale gas and other reservoirs described in Embodiment 4, the difference is that:

In this embodiment, the well depth of the target layer is 3000m, the formation fracture pressure is 61MPa, the length of the open hole section is 8m, the central aperture of the new perforating charge 7 is 5mm, and the perforating, explosive and fracturing integrated device is selected with three rows of grooves 12 according to the construction requirements. The perforation, explosion and fracturing integrated pipe string 8 is used to create joints, in which a row of grooves 12 has four strip grooves.

Example 6

According to the perforation and fracturing method of the methane in-situ perforation and explosion fracturing integrated device in the open-hole section of horizontal wells in complex tight gas, shale gas and other reservoirs described in Embodiment 4, the difference is that:

In this embodiment, the depth of the target layer is 4000m, the formation fracture pressure is 82MPa, the length of the open hole section is 10m, the central aperture of the new perforating charge 7 is 5mm, and the perforation, explosion and fracturing integrated device is selected with five rows of grooves 12 according to the construction requirements. The perforation, explosion and fracturing integrated pipe string 8 is used to create joints, in which a row of grooves 12 has 5 strip grooves.

Claims (12)

1. The horizontal well open hole section methane in-situ perforation, explosion and fracturing integrated device suitable for the complex dense gas and shale gas reservoirs is characterized by comprising a detonation device and a perforation, explosion and fracturing integrated device which are connected in sequence;

the detonation device is used for carrying the combustion improver into the well, controlling the pumping of the combustion improver and controlling the discharge of waste gas;

the perforation, blasting and fracturing integrated device is used for completing perforation and fracturing operation of a target layer fracturing section;

the perforation, blasting and fracturing integrated device comprises a perforation bullet and perforation, blasting and fracturing integrated tubular column;

the wall surface of the perforation blasting fracturing integrated tubular column is provided with a groove for bearing the perforating charges and guiding blasting gas to directionally form a seam; the space in the perforation, blasting and fracturing integrated tubular column forms a containing cavity;

the detonation device comprises a combustion improver storage tank, a pressurizing and pumping system, an exhaust emission system and an igniter;

the combustion improver storage tank is used for carrying the combustion improver into the well;

one end of the pressurizing and pumping system is connected with the combustion improver storage tank, the other end of the pressurizing and pumping system is connected with the perforation, combustion, explosion and fracturing integrated device, and pumping of the combustion improver is controlled through the pressurizing and pumping system;

and one end of the exhaust gas emission system is connected with an annular space outside the gas exhaust transmission ignition pipe column, the other end of the exhaust gas emission system is connected with the perforation, combustion, explosion and fracturing integrated device, and the exhaust gas emission is controlled through the exhaust gas emission system.

2. The horizontal well naked eye section methane in-situ perforation, combustion and explosion and fracturing integrated device suitable for complex dense gas and shale gas reservoirs is characterized in that a pressurizing pumping system, an exhaust emission system and an igniter are integrated in the same gas discharging and conveying ignition pipe column, one end of the gas discharging and conveying ignition pipe column is provided with an internal thread joint and is connected with a combustion improver storage tank, and the other end of the gas discharging and conveying ignition pipe column is provided with an external thread joint and is connected with the perforation, combustion and explosion and fracturing integrated device.

3. The horizontal well open hole section methane in-situ perforation, combustion and explosion integrated device suitable for complex dense gas and shale gas reservoirs according to claim 2, wherein perforations are reserved in perforating charges, and shaped charges are filled in the perforating charges.

4. The horizontal well open hole section methane in-situ perforation, combustion and explosion integrated device suitable for complex dense gas and shale gas reservoirs according to claim 3, wherein the aperture of the perforation of the perforating bullet is not less than 5mm.

5. The horizontal well open hole section methane in-situ perforation, combustion and explosion and fracturing integrated device suitable for complex dense gas and shale gas reservoirs according to claim 4, wherein the grooves are strip-shaped grooves.

6. The horizontal well open hole section methane in-situ perforation, explosion and fracturing integrated device suitable for the complex dense gas and shale gas reservoirs is characterized in that at least two strip-shaped grooves are formed in the same circular section of the perforation, explosion and fracturing integrated tubular column, and the number of the strip-shaped grooves on the wall surface of the perforation, explosion and fracturing integrated tubular column is not less than three.

7. The horizontal well open hole section methane in-situ perforation, combustion and explosion and fracturing integrated device suitable for the complex dense gas and shale gas reservoirs, which is disclosed in claim 6, is characterized by further comprising a left buffer and a right buffer, wherein the left buffer and the right buffer are respectively arranged at two ends of the perforation, combustion and explosion and fracturing integrated tubular column.

8. The horizontal well open hole section methane in-situ perforation, combustion and explosion and fracturing integrated device suitable for complex dense gas and shale gas reservoirs is characterized by further comprising a tubular column auxiliary device;

the tubular column auxiliary device comprises a left centralizer, a right centralizer, a left open hole packer and a right open hole packer;

the left centralizer is arranged on the combustion improver storage tank shell, and the right centralizer is arranged at the end part of the perforation, combustion explosion and fracturing integrated device;

the left open hole packer is located in the middle of the gas drainage ignition pipe column, and the right open hole packer is located between the right buffer and the right centralizer and used for separating an annular space of the fracturing section.

9. The horizontal well open hole section methane in-situ perforation, combustion and explosion integrated device suitable for complex dense gas and shale gas reservoirs according to claim 8, wherein at least two left centralizers and at least one right centralizer are arranged.

10. The horizontal well open hole section methane in-situ perforation, combustion, explosion and fracturing integrated device suitable for complex dense gas and shale gas reservoirs according to claim 9, wherein the igniter comprises an ignition wire, the ignition wire is exposed in the perforation, combustion, explosion and fracturing integrated tubular column inner cavity, and the rest part of the igniter is hermetically installed in the gas discharging and transporting ignition tubular column.

11. The horizontal well open hole section methane in-situ perforation, combustion and explosion integrated device suitable for complex dense gas and shale gas reservoirs according to claim 10, wherein the ignition wire is made of high-strength conductive metal materials, including copper-chromium alloy, copper-silver alloy and nanocrystalline copper.

12. The perforation fracturing method of the horizontal well open hole section methane in-situ perforation burning explosion fracturing integrated device suitable for the complex dense gas and shale gas reservoirs is characterized by being realized by the horizontal well open hole section methane in-situ perforation burning explosion fracturing integrated device suitable for the complex dense gas and shale gas reservoirs, and comprises the following steps of:

(1) The perforating bullet is embedded into a strip-shaped groove of a perforating, burning, explosion and fracturing integrated tubular column, and a right buffer, a left buffer, a right open hole packer and a right centralizer are installed; then the gas discharging and transporting ignition pipe column with the left open hole packer and the combustion improver storage tank with the left centralizer are screwed in sequence;

(2) The methane in-situ perforation, blasting and fracturing integrated device of the open hole section of the horizontal well and the oil pipe column are put into the open hole fracturing section of the target layer of the horizontal well;

(3) After the left centralizer and the right centralizer control the in-situ perforation, combustion, explosion and fracturing integrated device of the methane in the open hole section of the horizontal well to be centered, the left open hole packer and the right open hole packer finish the setting of the open hole section, and separate annular spaces around the open hole section;

(4) Opening an exhaust emission system, discharging the annular space between the left open hole packer and the right open hole packer and the gas in the containing cavity of the perforating, blasting and fracturing integrated tubular column, and enabling methane gas desorbed from the reservoir to enter the containing cavity through the holes reserved by the perforating charges;

(5) After the methane gas fills the cavity, closing the waste gas discharge system, starting the pressurizing and pumping system, conveying the combustion improver into the cavity, and closing the pressurizing and pumping system after the mixing proportion requirement is met;

(6) After the gas storage is finished, the igniter ignites, high-temperature high-pressure explosive gas impacts the burning reservoir through the holes of the perforating bullet on one hand, and on the other hand, the explosive cover is bombarded to promote the explosive to explode, high-speed metal jet flow is generated, the reservoir is penetrated, and perforation of the fracturing section is finished cooperatively;

(7) After perforation operation is completed, exhaust gas is discharged, methane gas in a reservoir is introduced, combustion improver is pumped in, ignition and detonation are carried out, and the explosion gas is directionally ejected out through the strip-shaped grooves to form a horizontal well open hole section radial multi-slit three-dimensional seam net;

(8) Repeating the step (7), namely completing multistage repeated fracturing operation of the target layer fracturing section under the condition of not moving the pipe column, so that the volume of the fracture network is expanded;

(9) After the fracturing of the target layer fracturing section is completed, the methane in-situ perforation, blasting and fracturing integrated device of the open hole section of the horizontal well is withdrawn from the shaft, the perforating charges are reinstalled, and the perforation, blasting and fracturing process is repeated in the next fracturing section, so that staged fracturing is realized.