US2024044237A1PendingUtilityA1
Method of shale gas reservoir stimulation by oxidation-induced rock burst
Est. expirySep 8, 2041(~15.1 yrs left)· nominal 20-yr term from priority
E21B 43/27E21B 49/00E21B 43/263E21B 43/26
37
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Claims
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.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method of a shale gas reservoir stimulation by an oxidation-induced rock burst, comprising:
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):
V
1
=
α
(
2
LHW
+
(
D
-
2
δ
)
2
4
π
h
)
formula
(
1
)
in the formula (1), V 1 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), P o 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; Z o represents a gas compression factor before the oxidation-induced rock burst; Z m represents a gas compression factor after the oxidation-induced rock burst; T o represents an original formation temperature, K; m represents the mass of the hydrogen peroxide injected; M H2O2 represents a molar mass of the 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 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), V 2 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), V 4 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;
an amount of the second slick water injected is calculated according to formula (5):
V
5
=
2
LHW
+
(
D
-
2
δ
)
2
4
π
h
formula
(
5
)
in the formula (5), V 5 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), V 2 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.Join the waitlist — get patent alerts
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