METHOD OF SHALE GAS RESERVOIR STIMULATION BY OXIDATION-INDUCED ROCK BURST

Abstract

A method of a shale gas reservoir stimulation by oxidation-induced rock burst includes performing a hydraulic fracturing stimulation on a shale gas well to be fractured; during the hydraulic fracturing, successively pumping slick water A, oxidizing fluid, glue liquid-containing slick water, catalytic decomposition fluid, and slick water B in a form of liquid slug. In the present invention, methane released by fracturing by the slick water A is mixed with oxygen generated by decomposition of hydrogen peroxide in the oxidizing fluid to induce oxidation-induced rock burst. Based on the physical properties and chemical thermodynamic properties of shale, a calculation method for the amount of fracturing fluid used and the radius of oxidation-induced rock burst is proposed, thereby realizing safe, efficient, and non-destructive multi-scale stimulation of hydraulic fractures-burst fractures-dissolution pores and fractures.

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS

This application is the national phase entry of International Application No. PCT/CN2021/132628, filed on Nov. 24, 2021, which is based upon and claims priority to Chinese Patent Application No. 202111048694.2, filed on Sep. 8, 2021, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a new method of stimulation in the technical field of oil and natural gas exploitation, and particularly relates to a method of shale gas reservoir stimulation by oxidation-induced rock burst.

BACKGROUND

Shale reservoirs are generally characterized by dense matrix and strong heterogeneity. Matrix pore throats mainly include nano-scale organic pores and clay mineral intergranular pores. Matrix permeability mainly ranges from nanodarcy to microdarcy. Shale gas seepage resistance is huge, with the coexistence of adsorbed/free gas. Shale gas production needs a series process of desorption-diffusion-seepage. However, the desorption-diffusion process of adsorbed gas in nanopores is slow, and the resistance of free gas diffusion-seepage is large, resulting in an extremely low shale gas transmission capacity. Therefore, an effective stimulation technology is required.

At present, multi-stage hydraulic fracturing of horizontal well is the primary means for shale oil and gas reservoir stimulation. Firstly, hydraulic fracturing breaks the shale matrix and opens natural fractures, allowing the formation of a complex artificial fracture network inside the gas reservoir, shortening the flow distance of gas seeping from matrix pores to fractures, increasing the discharge area, and realizing the economic development of shale gas reservoirs. However, the recovery of shale gas reservoirs is generally low, and the recovery of shale oil and gas reservoirs is much lower than that of conventional oil and gas reservoirs, accounting only about 10% to 16%. The recovery of shale gas reservoirs in North America is generally 5% to 20%, especially in the Barnett area, the recovery is only about 10%. From the perspective of long-term development, enhancing recovery is an inevitable choice for shale oil and gas development.

Secondly, although the fracture network formed by a primary hydraulic fracturing is beneficial to improving the seepage capacity of shale gas reservoirs, it still cannot solve the problem of low desorption-diffusion transmission capacity of gas in the matrix pores at the distal end of fracture, which causes the gas supply capacity of the shale matrix is far lower than the gas transmission capacity in the fracture. As a result, the production of gas wells in the early stage of exploitation decreases exponentially, the commercial exploitation period is shortened, the recovery is reduced, and the development cost is increased.

Analysis suggests that improving the production efficiency of methane in shale matrix is fundamentally to increase the diffusion rate of adsorbed gas and free gas. Due to the dense shale matrix, microfractures become the main channels for gas seepage. Thus, promoting the generation of microfractures to shorten the diffusion path of methane in nanopores is a main idea of hydraulic fracturing stimulation of shale gas reservoirs. Studies have shown that, compared with hydraulically supported fractures, unsupported fractures formed by stress disturbance during fracturing have a larger contact area with the shale matrix, control a wider range of seepage areas, and are very significant for delaying the rapid decline of shale gas well production. Therefore, on the basis of hydraulic fracturing, obtaining more unsupported fractures or secondary microfractures is one of the important breakthroughs to strengthen fracturing stimulation effect and improve shale gas recovery.

SUMMARY

The objective of the present invention is to achieve the secondary stimulation of a shale gas reservoir by generating local burst in a fractured well segment based on the existing hydraulic fracturing technology, so as to increase the fracture-making efficiency and the fracture density of the existing fracturing stimulation method and supplement and enhance the effect of the existing fracturing stimulation. In the present invention, slick water A, oxidizing fluid-glue, liquid-containing slick water, catalytic decomposition fluid and slick water B are successively injected to an in-well fracturing fluid in a form of liquid slug. Methane released by fracturing by the slick water A is mixed with oxygen generated by decomposition of hydrogen peroxide in the oxidizing fluid, which results in oxidation-induced rock burst, thereby achieving rapid, low-cost, and non-destructive stimulation effect.

The specific technical solutions of the present invention are as follows:

A method of shale gas reservoir stimulation by oxidation-induced rock burst, including:

• • performing a hydraulic fracturing stimulation on a shale gas well to be fractured;
  • during the hydraulic fracturing, successively pumping slick water A, oxidizing fluid, glue liquid-containing slick water, catalytic decomposition fluid, and slick water B in a form of liquid slug.

The slick water A is mainly used for fracture making by hydraulic fracturing and releasing a part of methane.

The oxidizing fluid is a mixture of hydrogen peroxide and dilute hydrochloric acid, and the dilute hydrochloric acid is used to prevent the decomposition of the hydrogen peroxide in a wellbore.

The amount of the glue liquid-containing slick water injected must be greater than the effective volume of the wellbore, which ensures the hydrogen peroxide in the wellbore to totally enter fractures and prevents a catalytic decomposition agent in the catalytic decomposition fluid from reacting in advance with the hydrogen peroxide in the oxidizing fluid in the wellbore.

The catalytic decomposition fluid uses slick water containing a catalytic decomposition agent. The catalytic decomposition agent includes, but is not limited to, sodium hydroxide and manganese dioxide.

The slick water B seals and isolates the oxidizing fluid, which makes the local burst in shale hydraulic fractures occur away from the end of the wellbore and protects the integrity of the wellbore.

As a preferred technical solution, the amount of the slick water A injected is calculated according to the following formula:

$V_1=\alpha \left(2\mathrm{LHV}+\frac{{\left(D-2\delta \right)}^2}{4}\pi h\right)$

In the formula, V₁ represents a volume of the slick water A; α represents a leakage coefficient, set as 1.0-1.5; D represents an outer diameter of a casing; δ represents a wall thickness of the casing; h represents a well depth; L represents a burst point depth; H represents a height of a major fracture of hydraulic fracturing; and W represents a width of the major fracture of hydraulic fracturing.

As a preferred technical solution, the oxidizing fluid is a mixture of hydrogen peroxide and dilute hydrochloric acid.

As a preferred technical solution, the mass of hydrogen peroxide injected and the radius of oxidation-induced rock burst are calculated according to the following formula:

$2\varphi \pi r^3\left(P_O+\sigma \right)=Z_{m}R\left(\frac{2P_o\varphi \pi r^3}{Z_o{\mathrm{RT}}_o}+\frac{m}{2M_{H2O2}}\right)\left(\frac{16\mathrm{qm}}{136{\mathrm{CM}}_{\mathrm{CH}4}\left(\frac{2P_o\varphi \pi r^3}{Z_o{\mathrm{RT}}_o}+\frac{m}{2M_{H2O2}}\right)}+T_o\right)$

In the formula, P_o represents an original formation pressure; σ represents a tensile strength of rock; ϕ represents a porosity of a tight gas layer; r represents a radius of oxidation-induced rock burst; R represents an ideal gas constant; Z_o represents a gas compression factor before oxidation-induced rock burst; Z_m represents a gas compression factor after oxidation-induced rock burst; T_o represents an original formation temperature, K; m represents a mass of hydrogen peroxide injected; M_H2O2 represents a molar mass of hydrogen peroxide; M_CH4 represents a molar mass of methane; C represents a specific heat capacity of methane; and q represents a calorific value of methane when the product is gaseous water.

As a preferred technical solution, according to the calculation formula of the mass of hydrogen peroxide injected and the radius of oxidation-induced rock burst, the mass m of hydrogen peroxide injected is given to yield the one-dimensional higher-order equation of the radius r of oxidation-induced rock burst. The one-dimensional higher-order equation of the radius r of oxidation-induced rock burst is solved to obtain the radius r of oxidation-induced rock burst.

Alternatively, according to the calculation formula of the mass of hydrogen peroxide injected and the radius of oxidation-induced rock burst, the radius r of oxidation-induced rock burst is given to yield the one-dimensional higher-order equation of the mass m of hydrogen peroxide injected. The one-dimensional higher-order equation of the mass m of hydrogen peroxide injected is solved to obtain the mass m of hydrogen peroxide injected.

As a preferred technical solution, the amount of the glue liquid-containing slick water injected is greater than the effective volume of the wellbore.

As a preferred technical solution, the amount of the glue liquid-containing slick water injected is calculated according to the following formula:

$V_2=\beta \frac{{\left(D-2\delta \right)}^2}{4}\pi h$

In the formula, V₂ represents a volume of the glue liquid-containing slick water; β represents a safety factor, set as 1.0-1.5. D represents an outer diameter of a casing; δ represents a wall thickness of the casing; and h represents a well depth.

As a preferred technical solution, the catalytic decomposition fluid is prepared by adding a catalytic decomposition agent into slick water. The catalytic decomposition agent includes, but is not limited to, sodium hydroxide and manganese dioxide.

As a preferred technical solution, the amount of the catalytic decomposition fluid injected is calculated according to the following formula:

$V_4=\frac{m}{0.2\rho }$

In the formula, V₄ represents a volume of the catalytic decomposition fluid; ρ represents a density of the slick water; and m represents a mass of hydrogen peroxide injected.

As a preferred technical solution, the slick water B is used to seal and isolate the oxidizing fluid, which makes the local burst in shale hydraulic fractures occur away from the end of the wellbore and protects the integrity of the wellbore.

The amount of the slick water B injected is calculated according to the following formula:

$V_5=2\mathrm{LHW}+\frac{{\left(D-2\delta \right)}^2}{4}\pi h$

In the formula, V₅ represents a volume of the slick water B; D represents an outer diameter of a casing; δ represents a wall thickness of the casing; h represents a well depth; L represents a burst point depth; H represents a height of a major fracture of hydraulic fracturing; and W represents a width of the major fracture of hydraulic fracturing.

The advantages are as follows:

• • (1) The density and complexity of fracture network are increased. Artificial fractures are formed by hydraulic fracturing, and the fracture density and depth are further enhanced through oxidation-induced rock burst, thereby forming a denser spherical fracture network.
  • (2) The construction operations are convenient and safe. In the process of hydraulic fracturing, the injection into a reservoir is conducted in a form of liquid slug along with conventional fracturing fluid, and a reasonable amount of the fracturing fluid injected makes oxidation-induced rock burst occur in hydraulic fractures far away from the wellbore.
  • (3) The chemical energy is fully utilized and the economic cost is low. Considering the combined action of combustible gas explosion generating high temperature and high pressure, the range of oxidation-induced rock burst is calculated to provide guidance for process implementation. At the same time, the hydrogen peroxide solution is widely used in many stages of oil exploration and development, the price of which is relatively low, effectively controlling the economic cost of fracturing stimulation.
  • (4) In the present invention, oxygen is generated by the decomposition of hydrogen peroxide to induce local methane explosion in fractures of a reservoir, further stimulating the shale gas reservoir. The method of the present invention is established based on an existing hydraulic fracturing shale gas well without additional drilling, and the required energy derives from hydrocarbon gas and oxygen produced by the decomposition of hydrogen peroxide in the reservoir, which reduces the cost of shale oil and gas exploitation and further improves the effect of hydraulic fracturing stimulation. When the scale of hydraulic fracturing is the same, oxidation-induced rock burst and hydraulic fracturing stimulation will be conductive to increasing the stimulated reservoir volume (SRV). For deeper shale gas reservoirs (≥3500 m), in the case of poor hydraulic fracturing effect, the present invention provides a new idea for the effective development of deep shale gas.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, a brief introduction of the accompanying drawings that are required to be used in the description of the specific embodiments or the prior art will be present below. In FIGS. 1-3, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn to actual scale.

FIG. 1 is a schematic diagram showing the inflow of working fluid in a multi-stage hydraulic fracturing process of a horizontal well in a shale gas reservoir according to an embodiment of the present invention;

FIG. 2 is a schematic diagram showing the process of the inflow of fracturing fluid and the generation of oxygen after a first-stage hydraulic fracturing according to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing the first-stage shale gas reservoir stimulation by oxidation-induced rock burst according to an embodiment of the present invention;

In FIGS. 1-3, a-shale gas reservoir; b-slick water B; c-catalytic decomposition fluid; d-glue liquid-containing slick water; e-oxidizing fluid; f-slick water A; g-bridge plug; h-horizontal well; i-major fracture of hydraulic fracturing; j-oxidizing fluid and catalytic decomposition fluid; k-fracture network formed by oxidation-induced rock burst.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

It should be noted that, all directional indications (such as up, down, left, right, front, back . . . ) in the embodiments of the present invention are only used to explain the relative positional relationship, movement situation, etc. of various elements under a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications also change accordingly.

In addition, expressions such as “first”, “second”, etc. involved in the present invention are only for the purpose of description, and should not be construed as indicating or implying relative importance thereof or implicitly indicating the number of the technical features referred. Thus, features defined by “first” and “second” may expressly or implicitly include at least one of the features. In the description of the present invention, “plurality” means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the invention.

The present invention is now further described with reference to the accompanying drawings.

As shown in FIG. 1, a horizontal well of a shale gas reservoir is subjected to a hydraulic fracturing stimulation based on the present invention. An in-well working fluid is injected in sequence in a form of liquid slug. The slick water A (f in FIG. 1) is pumped in the early stage for the hydraulic fracturing stimulation (FIG. 2), which creates conditions for the full contact of the subsequently injected oxidizing fluid (e in FIG. 2) and catalytic decomposition fluid (c in FIG. 2) in artificial fractures. The glue liquid-containing slick water (d in FIG. 2) is used to separate the oxidizing fluid from the catalytic decomposition fluid in a wellbore. Subsequently, the slick water B (b in FIG. 3) is pumped to drive the oxidizing fluid into interior of the fractures, making the point of oxidation-induced rock burst away from the wellbore. Considering the pump pressure during fracturing, the methane content in the artificial fractures is constant. When the amount of oxygen generated by the catalytic decomposition of a hydrogen peroxide solution reaches the range required for oxidation-induced shale rock burst, the mixed gas of methane and oxygen deflagrates at high temperature and high pressure to fracture the shale matrix, resulting in the generation of a fracture network caused by rock burst (k in FIG. 3) and realizing the secondary stimulation of reservoir.

There are differences in the explosion limit of methane when the methane is mixed with different gases. At normal temperature and normal pressure, the explosion limit of methane in air is about 5%-15%; the explosion limit of methane in pure oxygen is about 5.0%-61%. High temperature and high pressure lead to more violent molecular thermal motion. The explosion limit of a methane-air mixture is 2.87%-64.40% at 20 MPa and 100° C., and the critical oxygen content of explosion theoretically can be reduced to 5.74%. Therefore, the amount of hydrogen peroxide injected can be adjusted to achieve the proportion required for methane explosion.

In the embodiment of the present invention, a deep shale gas well of the Longmaxi Formation in the Sichuan Basin is taken as an example for calculating the amount of a fracturing fluid required for oxidation-induced rock burst.

(1) Slick Water A

The amount of the slick water A used is determined according to the position of burst point and the morphology of hydraulic fracture and adjusted according to small-scale fracturing test.

$V_1=\alpha \left(2\mathrm{LHW}+\frac{{\left(D-2\delta \right)}^2}{4}\pi h\right)$

In the formula, V₁ represents a volume of the slick water A, m³; α represents a leakage coefficient, set as 1.0-1.5; D represents an outer diameter of a casing, m; δ represents a wall thickness of the casing, m; h represents a well depth, m; L represents a burst point depth, m; H represents a height of a major fracture of hydraulic fracturing, m; and W represents a width of the major fracture of hydraulic fracturing, m.

The casing has an outer diameter of 139.7 mm and a wall thickness of 12.7 mm. The well depth is 5100 m. The first burst point depth is 70 m. The major fracture of hydraulic fracturing has a height of 20 m and a width of 0.03 m. The amount of the slick water A used is 164 m³.

(2) Oxidizing Fluid and Range of Oxidation-Induced Rock Burst

The oxidizing fluid is a mixture of hydrogen peroxide and dilute hydrochloric acid (the mass concentration of the hydrogen peroxide is 20%). The occurrence of oxidation-induced rock burst depends on two reactions including the decomposition of hydrogen peroxide to generate oxygen and the combustion of oxygen and methane mixed. The mass of the hydrogen peroxide injected determines the range involved, that is, the radius of a fracture network formed by oxidation-induced rock burst. The maximum explosion pressure generated in the explosion of mixture can be determined according to the relationship that pressure is directly proportional to thermodynamic temperature and mole number. The mass of hydrogen peroxide injected and the range of oxidation-induced rock burst are calculated as follows:

$2\varphi \pi r^3\left(P_O+\sigma \right)=Z_{m}R\left(\frac{2P_o\varphi \pi r^3}{Z_o{\mathrm{RT}}_o}+\frac{m}{2M_{H2O2}}\right)\left(\frac{16\mathrm{qm}}{136{\mathrm{CM}}_{\mathrm{CH}4}\left(\frac{2P_o\varphi \pi r^3}{Z_o{\mathrm{RT}}_o}+\frac{m}{2M_{H2O2}}\right)}+T_o\right)$

In the formula, P_o represents an original formation pressure, Pa; σ represents a tensile strength of rock, Pa; ϕ represents a porosity of a tight gas layer; r represents a radius of oxidation-induced rock burst,m; R represents an ideal gas constant, 8.314 J mol⁻¹·K⁻¹; Z_o represents a gas compression factor before oxidation-induced rock burst; Z_m represents a gas compression factor after oxidation-induced rock burst; T_o represents an original formation temperature, K; m represents a mass of hydrogen peroxide injected, g; M_H2O2 represents a molar mass of hydrogen peroxide, 34 g/mol; M_CH4 represents a molar mass of methane, 16 g/mol; C represents a specific heat capacity of methane, 2.227 kJ/(kg·K); and q represents a calorific value of methane when the product is gaseous water, 50200 kJ/kg.

According to the above formula, m is given to yield the one-dimensional higher-order equation of r, which is solved by a bisection method.

In the example, the original formation pressure is 66.8 MPa, the tensile strength of rock after hydration is 6.3 MPa, the original formation temperature is 393 K, the average porosity is 4.17%, the gas compression factors before and after oxidation-induced rock burst are both 1.2, the amount of oxidizing fluid used is 5000 kg (hydrogen peroxide is 1000 kg), and the radius of oxidation-induced rock burst is 8.5 m.

(3) Glue Liquid-Containing Slick Water

The glue liquid-containing slick water is used to press the oxidizing fluid from the wellbore into the formation to prevent the reaction of hydrogen peroxide and catalyst in the wellbore, and the amount used is 1.2 times the volume of the wellbore.

$V_2=\beta \frac{{\left(D-2\delta \right)}^2}{4}\pi h$

In the formula, V₂ represents a volume of the glue liquid-containing slick water, m³; and β represents a safety factor, set as 1.0-1.5.

The parameters are the same as those of the slick water A, and the amount of the glue liquid-containing slick water used is 63 m³.

(4) Catalytic Decomposition Fluid

The catalytic decomposition fluid uses slick water containing a catalytic decomposition agent, with a volume being the same as that of the oxidizing fluid. The catalytic decomposition agent includes, but is not limited to, sodium hydroxide and manganese dioxide.

$V_4=\frac{m}{0.2\rho }$

In the formula, V₄ represents a volume of the catalytic decomposition fluid, m³; and ρ represents a density of the slick water, kg/m³.

The density of the slick water is 1000 kg/m³, and the amount of the catalytic decomposition fluid used is 5 m³.

(5) Slick Water B

The slick water B is used to drive hydrogen peroxide and catalyst into the interior of fractures to avoid the wellbore being affected by oxidation-induced rock burst and protect the integrity of the wellbore.

$V_5=2\mathrm{LHW}+\frac{{\left(D-2\delta \right)}^2}{4}\pi h$

In the formula, V₅ represents a volume of the slick water B, m³.

Other parameters are the same as those of the slick water A, and the amount of the slick water B used is 136 m³.

According to the calculation method provided by the present invention, the total amount of fracturing fluid used in oxidation-induced rock burst is 373 m³, and a fracture network caused by oxidation-induced rock burst is generated at a location 70 m from each of two wings of the wellbore, with the radius of the fracture network being 8.5 m.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that the technical solutions recited in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, all of which should be included within the scope of the claims and specification of the present invention.

Claims

1. A method of a shale gas reservoir stimulation by an oxidation-induced rock burst, comprising: V 1 = α ( 2 ⁢ LHW + ( D - 2 ⁢ δ ) 2 4 ⁢ π ⁢ h ) formula ⁢ ( 1 )

performing a hydraulic fracturing stimulation on a shale gas well to be fractured;

during the hydraulic fracturing stimulation, successively pumping a first slick water, an oxidizing fluid, a glue liquid-containing slick water, a catalytic decomposition fluid, and a second slick water in a form of a liquid slug;

wherein an amount of the first slick water injected is calculated according to formula (1):

in the formula (1), V1 represents a volume of the first slick water; α represents a leakage coefficient, set as 1.0-1.5; D represents an outer diameter of a casing; δ represents a wall thickness of the casing; h represents a well depth; L represents a burst point depth; H represents a height of a major fracture of the hydraulic fracturing stimulation; and W represents a width of the major fracture of the hydraulic fracturing stimulation.

2. (canceled)

3. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 1, wherein the oxidizing fluid is a mixture of hydrogen peroxide and dilute hydrochloric acid.

4. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 3, wherein a mass of the hydrogen peroxide injected and a radius of the oxidation-induced rock burst are calculated according to formula (2): 2 ⁢ ϕ ⁢ π ⁢ r 3 ( P O + σ ) = Z m ⁢ R ⁡ ( 2 ⁢ P o ⁢ ϕ ⁢ π ⁢ r 3 Z o ⁢ RT o + m 2 ⁢ M H ⁢ 2 ⁢ O ⁢ 2 ) ⁢ ( 16 ⁢ qm 136 ⁢ CM CH ⁢ 4 ( 2 ⁢ P o ⁢ ϕ ⁢ π ⁢ r 3 Z o ⁢ RT o + m 2 ⁢ M H ⁢ 2 ⁢ O ⁢ 2 ) + T o ) formula ⁢ ( 2 )

in the formula (2), Po represents an original formation pressure; σ represents a tensile strength of a rock; ϕ represents a porosity of a tight gas layer; r represents the radius of the oxidation-induced rock burst; R represents an ideal gas constant; Zo represents a gas compression factor before the oxidation-induced rock burst; Zm represents a gas compression factor after the oxidation-induced rock burst; To represents an original formation temperature, K; m represents the mass of the hydrogen peroxide injected; MH2O2 represents a molar mass of the hydrogen peroxide; MCH4 represents a molar mass of methane; C represents a specific heat capacity of methane; and q represents a calorific value of methane when a product is a gaseous water.

5. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 4, wherein according to the formula (2) of the mass of the hydrogen peroxide injected and the radius of the oxidation-induced rock burst, the mass m of the hydrogen peroxide injected is given to yield a one-dimensional higher-order equation of the radius r of the oxidation-induced rock burst, the one-dimensional higher-order equation of the radius r of the oxidation-induced rock burst is solved to obtain the radius r of the oxidation-induced rock burst;

alternatively, according to the formula (2) of the mass of the hydrogen peroxide injected and the radius of the oxidation-induced rock burst, the radius r of the oxidation-induced rock burst is given to yield a one-dimensional higher-order equation of the mass m of the hydrogen peroxide injected, the one-dimensional higher-order equation of the mass m of the hydrogen peroxide injected is solved to obtain the mass m of hydrogen peroxide injected.

6. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 1, wherein an amount of the glue liquid-containing slick water injected is greater than an effective volume of a wellbore.

7. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 1, wherein an amount of the glue liquid-containing slick water injected is calculated according to formula (3): V 2 = β ⁢ ( D - 2 ⁢ δ ) 2 4 ⁢ π ⁢ h formula ⁢ ( 3 )

in the formula (3), V2 represents a volume of the glue liquid-containing slick water; β represents a safety factor, set as 1.0-1.5. D represents the outer diameter of the casing; δ represents the wall thickness of the casing; and h represents the well depth.

8. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 1, wherein the catalytic decomposition fluid is prepared by adding a catalytic decomposition agent into a third slick water, the catalytic decomposition agent comprises sodium hydroxide and manganese dioxide.

9. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 4, wherein an amount of the catalytic decomposition fluid injected is calculated according to formula (4): V 4 = m 0.2 ρ formula ⁢ ( 4 )

in the formula (4), V4 represents a volume of the catalytic decomposition fluid; ρ represents a density of a third slick water; and m represents the mass of the hydrogen peroxide injected.

10. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 1, wherein the second slick water is used to seal and isolate the oxidizing fluid to make a local burst in shale hydraulic fractures occur away from an end of a wellbore and protect an integrity of the wellbore; V 5 = 2 ⁢ LHW + ( D - 2 ⁢ δ ) 2 4 ⁢ π ⁢ h formula ⁢ ( 5 )

an amount of the second slick water injected is calculated according to formula (5):

in the formula (5), V5 represents a volume of the second slick water; D represents the outer diameter of the casing; δ represents the wall thickness of the casing; h represents the well depth; L represents the burst point depth; H represents the height of the major fracture of the hydraulic fracturing stimulation; and W represents the width of the major fracture of the hydraulic fracturing stimulation.

11. The method of the shale gas reservoir stimulation by the oxidation-induced rock burst according to claim 6, wherein the amount of the glue liquid-containing slick water injected is calculated according to formula (3): V 2 = β ⁢ ( D - 2 ⁢ δ ) 2 4 ⁢ π ⁢ h formula ⁢ ( 3 )

in the formula (3), V2 represents a volume of the glue liquid-containing slick water; β represents a safety factor, set as 1.0-1.5. D represents the outer diameter of the casing; δ represents the wall thickness of the casing; and h represents the well depth.