CN117709125B - Shale oil and gas reservoir volume fracturing design method capable of preventing fault activation - Google Patents
Shale oil and gas reservoir volume fracturing design method capable of preventing fault activation Download PDFInfo
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- CN117709125B CN117709125B CN202410065340.6A CN202410065340A CN117709125B CN 117709125 B CN117709125 B CN 117709125B CN 202410065340 A CN202410065340 A CN 202410065340A CN 117709125 B CN117709125 B CN 117709125B
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 230000004913 activation Effects 0.000 title claims abstract description 24
- 239000003079 shale oil Substances 0.000 title claims abstract description 19
- 238000010276 construction Methods 0.000 claims abstract description 85
- 238000004364 calculation method Methods 0.000 claims abstract description 12
- 239000012530 fluid Substances 0.000 claims description 20
- 238000006073 displacement reaction Methods 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 12
- 230000009471 action Effects 0.000 claims description 8
- 238000002347 injection Methods 0.000 claims description 8
- 239000007924 injection Substances 0.000 claims description 8
- 239000011435 rock Substances 0.000 claims description 8
- 238000010008 shearing Methods 0.000 claims description 5
- 241001181114 Neta Species 0.000 claims description 4
- 230000007547 defect Effects 0.000 abstract description 2
- 230000003213 activating effect Effects 0.000 abstract 1
- 230000002452 interceptive effect Effects 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000035699 permeability Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Abstract
The invention discloses a shale oil and gas reservoir volume fracturing design method for preventing fault activation, and belongs to the technical field of hydraulic fracturing; according to the method, the defect that the fault is not activated only by changing the position of a horizontal well, but not technical guidance can be provided for the fracturing design of a horizontal well which passes through the fault is overcome, and the fault is predicted and avoided in advance by reasonable arrangement and calculation of construction parameters, so that a new solution is provided for preventing the fault from activating and interfering with fracturing operation.
Description
Technical Field
The invention relates to the technical field of hydraulic fracturing, in particular to a shale oil and gas reservoir volume fracturing design method for preventing fault activation.
Background
Hydraulic fracturing is a technique for fracturing a formation by injecting a high pressure fluid into the formation to reform the formation permeability and increase productivity. Shale oil and gas reservoirs generally have low-pore and ultra-low permeability physical properties, and can be put into production only after large-scale hydraulic fracturing is carried out. The horizontal well segmented multi-cluster fracturing is a main technical means for implementing volume fracturing transformation of shale oil and gas reservoirs, and field practice shows that when a fracturing segment adjacent to a fault is transformed, a large amount of fracturing fluid enters the fault to increase pore pressure to induce the fault to activate so as to cause fault sliding, and the fault sliding causes sleeve shearing deformation so as to influence fracturing construction. In order to avoid the fault activation caused by the intersection of hydraulic cracks and faults in the construction process, the prior art provides a method for evaluating the fault avoidance safety distance in the hydraulic fracturing process based on ground stress, which can effectively evaluate whether the faults are activated in the hydraulic fracturing process and the hydraulic fracturing safety avoidance well position distance, but only can change the horizontal well position before drilling to avoid the faults, and when the horizontal well passes through the faults, whether the faults are activated cannot be judged, and accurate and proper engineering parameters cannot be provided for site construction, so that guidance cannot be provided for the shale oil and gas reservoir volume fracturing scheme design. Therefore, there is a need to propose a shale reservoir volume fracturing design method that prevents fault activation.
Disclosure of Invention
The invention aims to provide a shale oil and gas reservoir volume fracturing design method for preventing fault activation, which is used for optimizing shale oil and gas reservoir volume fracturing design, firstly determining the avoiding distance of adjacent perforation clusters according to well cementation quality, calculating and judging whether a hydraulic fracture is intersected with a fault, calculating whether the hydraulic fracture is activated after the hydraulic fracture is intersected with the fault in the intersecting condition, and setting a safe fracturing construction parameter value to prevent the fault from being activated in the hydraulic fracturing construction process and protect a construction pipeline.
In order to achieve the above purpose, the invention provides a shale oil and gas reservoir volume fracturing design method for preventing fault activation, which comprises the following steps:
S1: determining the avoiding distance of adjacent perforation clusters according to the fault development zone and the well cementation quality of the horizontal shaft section to be pressed;
s2: calculating the critical half-seam length and the critical half-seam height of the intersection of the hydraulic fracture and the fault based on the space geometry theory;
S3: according to the construction design, obtaining a design half-seam length and a design half-seam height, and comparing the critical half-seam length with the design half-seam length, the critical half-seam height and the design half-seam height respectively;
when the critical half-seam length and the critical half-seam height are both larger than the designed half-seam length and the designed half-seam height, the hydraulic fracture is not intersected with the fault, and then construction is carried out according to an initial fracturing design scheme; otherwise, the hydraulic fracture is intersected with the fault, and whether the fault is activated after the intersection is needed to be judged;
S4: in the step S3, when the hydraulic fracture intersects with the fault, calculating a critical net pressure value of the hydraulic fracture corresponding to the fault activation, introducing a safety coefficient by combining site construction experience, and calculating a safe construction net pressure value;
s5: calculating a hydraulic fracture net pressure value under the initial fracturing design scheme, comparing the hydraulic fracture net pressure value with a safe construction net pressure value, and executing according to the initial fracturing design scheme when the hydraulic fracture net pressure value is smaller than the safe construction net pressure value; when the net pressure value of the hydraulic fracture is larger than the net pressure value of the safety construction, an initial fracturing design scheme is adjusted;
s6: when the hydraulic fracture net pressure value is larger than the safe construction net pressure value, calculating a safe fracturing construction parameter value corresponding to the safe construction net pressure value in the step S4, and adjusting an initial fracturing design scheme according to the corresponding safe fracturing construction parameter value;
s7: and constructing according to the modified fracturing design scheme.
Preferably, in the step S1, the distance between the intersection point of the fault and the horizontal shaft and the adjacent perforation cluster is set as an avoiding distance, the well cementation quality is determined according to the acoustic amplitude variable density logging result, the avoiding distance is 15m when the well cementation quality is good, the avoiding distance is 20m when the well cementation quality is medium, and the avoiding distance is 25m when the well cementation quality is poor.
Preferably, in the step S2, the process of calculating the critical half-seam length and the critical half-seam height of the hydraulic fracture intersecting the fault is as follows:
based on a space geometric model, a critical half-seam length calculation formula for intersecting the hydraulic fracture and the fault;
Lfcritical＝Dperf tanα(1)
A critical half-seam height calculation formula for intersecting the hydraulic fracture and the fault;
Hfcritical＝Dperf tanγ(2)
in the formula, L fcritical is the critical half-seam length of the hydraulic fracture, and m;
H fcritical is critical half-seam height of the hydraulic fracture, m;
D perf is the evapotranspiration distance, m;
alpha is the included angle between the fault trend and the horizontal shaft;
Gamma is the fault inclination angle, degree.
Preferably, in the step S4, a hydraulic fracture critical net pressure value and a safety construction net pressure value are calculated, and the specific formulas are as follows:
Pneta＝δPnetl(5)
in the formula, P netl is a hydraulic fracture critical net pressure value corresponding to fault activation and MPa;
P neta is the net pressure of safe construction and MPa;
sigma n is normal stress applied to the fault wall surface under the action of three-dimensional ground stress, and MPa;
τ is the shearing stress applied to the fault plane under the action of three-dimensional ground stress, and MPa;
k f is the friction coefficient of the fault wall surface, and is dimensionless;
σ h is the original minimum horizontal ground stress, MPa;
σ H is the original maximum horizontal ground stress, MPa;
σ v is the original vertical ground stress, MPa;
gamma is the fault inclination angle;
Beta is the included angle between the fault trend and the horizontal maximum ground stress, and DEG;
Delta is a safety coefficient, dimensionless.
Preferably, in the step S5, a specific formula for calculating the net pressure value of the hydraulic fracture under the initial fracturing design scheme is as follows:
In the above formula, P net is the net pressure value of the hydraulic fracture under the initial fracturing design scheme and MPa;
e is the Young's modulus of stratum rock and Pa;
v is the stratum rock poisson ratio, dimensionless;
Q 0 is single-stage injection displacement when the horizontal well is fractured in stages, and m 3/s;
n is the number of single-section perforation clusters in staged fracturing of the horizontal well, and is dimensionless;
Mu is the viscosity of the fracturing fluid and Pa.s;
h f is hydraulic fracture height, m;
t is the total construction time, s.
Preferably, in the step S6, the safe fracturing construction parameters are calculated according to the safe net pressure value calculated in the step S4, and the specific process is as follows:
When the same viscosity fracturing fluid is adopted for construction on site, the safety discharge capacity is obtained, and the specific formula is as follows:
when the same displacement construction is adopted on site, the viscosity of the safe fracturing fluid is calculated, and the specific formula is as follows:
And adjusting an initial fracturing design scheme according to the field condition.
Therefore, the shale oil and gas reservoir volume fracturing design method for preventing fault activation overcomes the defect that the fault is only prevented from being activated by changing the position of the horizontal well in the prior art, but cannot provide guidance for the fracturing design of the horizontal well which passes through the fault, and the problem that the fault is activated can be effectively avoided by reasonably arranging and calculating construction parameters and optimizing the corresponding construction scheme, so that the method has obvious field application effect and good engineering application value.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a flow chart of a shale reservoir volume fracturing design method for preventing fault activation in accordance with the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments, and specific calculation methods adopt the prior art in the field, so that detailed descriptions thereof will not be repeated.
Examples
Referring to fig. 1, the invention provides a shale oil and gas reservoir volume fracturing design method for preventing fault activation, which comprises the following steps:
S1: determining the avoiding distance of adjacent perforation clusters according to the fault development zone and the well cementation quality of the horizontal shaft section to be pressed;
Setting the distance between the intersection point of the fault and the horizontal shaft and the adjacent perforation cluster as an avoiding distance, determining the well cementation quality according to the sound amplitude variable density well logging result, wherein the avoiding distance is 15m when the well cementation quality is good, the avoiding distance is 20m when the well cementation quality is medium, and the avoiding distance is 25m when the well cementation quality is poor;
S2: based on space geometry theory, calculating critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault, and calculating the critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault as follows:
based on a space geometric model, a critical half-seam length calculation formula for intersecting the hydraulic fracture and the fault;
Lfcritical＝Dperftanα(1)
A critical half-seam height calculation formula for intersecting the hydraulic fracture and the fault;
Hfcritical＝Dperftanγ(2)
in the formula, L fcritical is the critical half-seam length of the hydraulic fracture, and m;
H fcritical is critical half-seam height of the hydraulic fracture, m;
D perf is the evapotranspiration distance, m;
alpha is the included angle between the fault trend and the horizontal shaft;
Gamma is the fault inclination angle, degree.
S3: according to the construction design, obtaining a design half-seam length and a design half-seam height, and comparing the critical half-seam length with the design half-seam length, the critical half-seam height and the design half-seam height respectively;
when the critical half-seam length and the critical half-seam height are both larger than the designed half-seam length and the designed half-seam height, the hydraulic fracture is not intersected with the fault, and then construction is carried out according to an initial fracturing design scheme; otherwise, the hydraulic fracture is intersected with the fault, and whether the fault is activated after the intersection is needed to be judged;
S4: in the step S3, when the hydraulic fracture intersects with the fault, calculating a critical net pressure value of the hydraulic fracture corresponding to the fault activation based on a Moire-Coulomb intensity criterion, and introducing a safety coefficient by combining site construction experience to calculate a safe construction net pressure value;
calculating a critical net pressure value of the hydraulic fracture and a safe construction net pressure value, wherein the specific formulas are as follows:
Pneta＝δPnetl(5)
in the formula, P netl is a hydraulic fracture critical net pressure value corresponding to fault activation and MPa;
P neta is the net pressure of safe construction and MPa;
sigma n is normal stress applied to the fault wall surface under the action of three-dimensional ground stress, and MPa;
τ is the shearing stress applied to the fault plane under the action of three-dimensional ground stress, and MPa;
k f is the friction coefficient of the fault wall surface, and is dimensionless;
σ h is the original minimum horizontal ground stress, MPa;
σ H is the original maximum horizontal ground stress, MPa;
σ v is the original vertical ground stress, MPa;
gamma is the fault inclination angle;
Beta is the included angle between the fault trend and the horizontal maximum ground stress, and DEG;
Delta is a safety coefficient, dimensionless.
S5: calculating a hydraulic fracture net pressure value under the initial fracturing design scheme, comparing the hydraulic fracture net pressure value with a safe construction net pressure value, and executing according to the initial fracturing design scheme when the hydraulic fracture net pressure value is smaller than the safe construction net pressure value; when the net pressure value of the hydraulic fracture is larger than the net pressure value of the safe construction, an initial fracturing design scheme is adjusted, and the fracturing scale is reduced;
the specific formula for calculating the net pressure value of the hydraulic fracture under the initial fracturing design scheme is as follows:
In the above formula, P net is the net pressure value of the hydraulic fracture under the initial fracturing design scheme and MPa;
e is the Young's modulus of stratum rock and Pa;
v is the stratum rock poisson ratio, dimensionless;
Q 0 is single-stage injection displacement when the horizontal well is fractured in stages, and m 3/s;
n is the number of single-section perforation clusters in staged fracturing of the horizontal well, and is dimensionless;
Mu is the viscosity of the fracturing fluid and Pa.s;
h f is hydraulic fracture height, m;
t is the total construction time, s.
S6: when the hydraulic fracture net pressure value is larger than the safe construction net pressure value, calculating a safe fracturing construction parameter value corresponding to the safe construction net pressure value in the step S4, wherein the safe parameter value comprises displacement and fracturing fluid viscosity, and the process is as follows:
When the same viscosity fracturing fluid is adopted for construction on site, the safety discharge capacity is obtained, and the specific formula is as follows:
when the same displacement construction is adopted on site, the viscosity of the safe fracturing fluid is calculated, and the specific formula is as follows:
According to the field situation, an initial fracturing design scheme is adjusted, and according to the corresponding safe fracturing construction parameter value, the initial fracturing design scheme is modified;
s7: and constructing according to the modified fracturing design scheme.
In a specific experimental process, actual parameters are adopted for calculation, and the actual parameters are shown in the following table 1:
Table 1 well basic parameter table
| Basic parameters | Value taking | Basic parameters | Value taking |
| Cementing quality | Medium and medium | Fault strike and horizontal shaft angle (°) | 83 |
| Fault inclination angle (°) | 53 | Design half seam length (m) | 180 |
| Injection displacement (m 3/min) | 20 | Design half seam height (m) | 13 |
| Horizontal minimum ground stress (MPa) | 60.6 | Horizontal maximum ground stress (MPa) | 73.5 |
| Vertical ground stress (MPa) | 81 | Number of clusters per segment | 3 |
| Young's modulus (GPa) | 35 | Viscosity of fracturing fluid (mPa. S) | 10 |
| Poisson's ratio | 0.2 | Friction coefficient of fault wall | 0.6 |
| Safety factor | 0.6 | Construction time (min) | 120 |
The experimental calculation is carried out by adopting the parameters, and the process is as follows:
s1: according to the acoustic amplitude variable density logging result, determining that the well cementation quality is medium, and the avoiding distance of adjacent perforation clusters is 20m;
S2: based on space geometry theory, calculating critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault, and calculating the critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault as follows:
based on a space geometric model, a critical half-seam length calculation formula for intersecting the hydraulic fracture and the fault;
Lfcritical＝Dperftanα(1)
A critical half-seam height calculation formula for intersecting the hydraulic fracture and the fault;
Hfcritical＝Dperftanγ(2)
in the formula, L fcritical is the critical half-seam length of the hydraulic fracture, and m;
H fcritical is critical half-seam height of the hydraulic fracture, m;
D perf is the evapotranspiration distance, m;
alpha is the included angle between the fault trend and the horizontal shaft;
Gamma is the fault inclination angle, degree.
According to formulas (1) and (2) and combining parameters in table 1, the included angle between the fault trend and the horizontal shaft is 78 degrees, the fault inclination angle is 45 degrees, and the critical half-seam length is 162m and the half-seam height is 26.5m;
S3: according to the construction design, obtaining a design half-seam length and a design half-seam height, and comparing the critical half-seam length with the design half-seam length, the critical half-seam height and the design half-seam height respectively;
when the critical half-seam length and the critical half-seam height are both larger than the designed half-seam length and the designed half-seam height, the hydraulic fracture is not intersected with the fault, and then construction is carried out according to an initial fracturing design scheme; otherwise, the hydraulic fracture is intersected with the fault, and whether the fault is activated after the intersection is needed to be judged;
according to the parameters in Table 1, the critical half-seam length is smaller than the designed half-seam length, the hydraulic fracture is intersected with the fault, and whether the fault is activated after the intersection is judged;
S4: in the step S3, when the hydraulic fracture intersects with the fault, calculating a critical net pressure value of the hydraulic fracture corresponding to the fault activation, introducing a safety coefficient by combining site construction experience, and calculating a safe construction net pressure value;
calculating a critical net pressure value of the hydraulic fracture and a safe construction net pressure value, wherein the specific formulas are as follows:
Pneta＝δPnetl(5)
in the formula, P netl is a hydraulic fracture critical net pressure value corresponding to fault activation and MPa;
P neta is the net pressure of safe construction and MPa;
sigma n is normal stress applied to the fault wall surface under the action of three-dimensional ground stress, and MPa;
τ is the shearing stress applied to the fault plane under the action of three-dimensional ground stress, and MPa;
k f is the friction coefficient of the fault wall surface, and is dimensionless;
σ h is the original minimum horizontal ground stress, MPa;
σ H is the original maximum horizontal ground stress, MPa;
σ v is the original vertical ground stress, MPa;
gamma is the fault inclination angle;
Beta is the included angle between the fault trend and the horizontal maximum ground stress, and DEG;
Delta is a safety coefficient, dimensionless.
According to the parameters in Table 1, calculating the critical net pressure value of the hydraulic fracture to be 9MPa and the net pressure value of the safe construction to be 5.4MPa;
s5: calculating a hydraulic fracture net pressure value under the initial fracturing design scheme, comparing the hydraulic fracture net pressure value with a safe construction net pressure value, and executing according to the initial fracturing design scheme when the hydraulic fracture net pressure value is smaller than the safe construction net pressure value; when the net pressure value of the hydraulic fracture is larger than the net pressure value of the safe construction, an initial fracturing design scheme is adjusted, and the fracturing scale is reduced;
the specific formula for calculating the net pressure value of the hydraulic fracture under the initial fracturing design scheme is as follows:
In the above formula, P net is the net pressure value of the hydraulic fracture under the initial fracturing design scheme and MPa;
e is the Young's modulus of stratum rock and Pa;
v is the stratum rock poisson ratio, dimensionless;
Q 0 is single-stage injection displacement when the horizontal well is fractured in stages, and m 3/s;
n is the number of single-section perforation clusters in staged fracturing of the horizontal well, and is dimensionless;
Mu is the viscosity of the fracturing fluid and Pa.s;
h f is hydraulic fracture height, m;
t is the total construction time, s.
According to the parameters in table 1, the hydraulic fracture net pressure value under the initial fracturing design scheme is calculated to be 6MPa according to the formula (6), and compared with the safe construction net pressure value, the hydraulic fracture net pressure value under the initial fracturing design scheme is larger than the safe construction net pressure value, so that the initial fracturing design scheme needs to be adjusted;
S6: when the hydraulic fracture net pressure value is larger than the safe construction net pressure value, calculating a safe fracturing construction parameter value corresponding to the safe construction net pressure value in the step S4, wherein the safe parameter value comprises displacement and fracturing fluid viscosity, and the process is as follows:
When the same viscosity fracturing fluid is adopted for construction on site, the safety discharge capacity is obtained, and the specific formula is as follows:
when the same displacement construction is adopted on site, the viscosity of the safe fracturing fluid is calculated, and the specific formula is as follows:
According to the field situation, an initial fracturing design scheme is adjusted, and according to the corresponding safe fracturing construction parameter value, the initial fracturing design scheme is modified; in general field construction, the injection displacement of the fracturing fluid is changed according to the determined viscosity of the fracturing fluid so as to adjust the fracturing design scheme, the safe displacement is calculated according to a formula (7), wherein the net pressure value is the net pressure value of the safe construction, and the safe injection displacement is calculated to be 15.3m 3/min.
S7: and (3) performing construction according to the modified fracturing design scheme, wherein the optimized fracturing design scheme adopts injection displacement of 15.3m 3/min and fracturing fluid viscosity of 10 mPa.s.
Therefore, the shale oil and gas reservoir volume fracturing design method for preventing fault activation can be adopted, shale oil and gas reservoir volume fracturing design can be optimized, firstly, the avoiding distance of adjacent perforation clusters is determined according to well cementation quality, whether hydraulic cracks are intersected with faults or not is calculated and judged, whether the faults are activated after the hydraulic cracks are intersected with the faults or not is calculated under the intersecting condition, and the faults are prevented from being activated in the hydraulic fracturing construction process and construction pipelines are protected by setting safe fracturing construction parameter values.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting it, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that: the technical scheme of the invention can be modified or replaced by the same, and the modified technical scheme cannot deviate from the spirit and scope of the technical scheme of the invention.
Claims (4)
1. A shale oil and gas reservoir volume fracturing design method for preventing fault activation is characterized in that: the method comprises the following steps:
S1: determining the avoiding distance of adjacent perforation clusters according to the fault development zone and the well cementation quality of the horizontal shaft section to be pressed;
S2: based on space geometry theory, calculating critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault, and calculating the critical half-seam length and critical half-seam height of the intersection of the hydraulic fracture and the fault as follows:
based on a space geometric model, a critical half-seam length calculation formula for intersecting the hydraulic fracture and the fault;
Lfcritical＝Dperftanα (1)
A critical half-seam height calculation formula for intersecting the hydraulic fracture and the fault;
Hfcritical＝Dperftanγ (2)
in the formula, L fcritical is the critical half-seam length of the hydraulic fracture, and m;
H fcritical is critical half-seam height of the hydraulic fracture, m;
D perf is the evapotranspiration distance, m;
alpha is the included angle between the fault trend and the horizontal shaft;
gamma is the fault inclination angle;
S3: according to the construction design, obtaining a design half-seam length and a design half-seam height, and comparing the critical half-seam length with the design half-seam length, the critical half-seam height and the design half-seam height respectively;
when the critical half-seam length and the critical half-seam height are both larger than the designed half-seam length and the designed half-seam height, the hydraulic fracture is not intersected with the fault, and then construction is carried out according to an initial fracturing design scheme; otherwise, the hydraulic fracture is intersected with the fault, and whether the fault is activated after the intersection is needed to be judged;
S4: in the step S3, when the hydraulic fracture intersects with the fault, calculating a critical net pressure value of the hydraulic fracture corresponding to the fault activation, introducing a safety coefficient by combining site construction experience, and calculating a safe construction net pressure value;
calculating a critical net pressure value of the hydraulic fracture and a safe construction net pressure value, wherein the specific formulas are as follows:
Pneta＝δPnetl (5)
in the formula, P netl is a hydraulic fracture critical net pressure value corresponding to fault activation and MPa;
P neta is the net pressure of safe construction and MPa;
sigma n is normal stress applied to the fault wall surface under the action of three-dimensional ground stress, and MPa;
τ is the shearing stress applied to the fault plane under the action of three-dimensional ground stress, and MPa;
k f is the friction coefficient of the fault wall surface, and is dimensionless;
σ h is the original minimum horizontal ground stress, MPa;
σ H is the original maximum horizontal ground stress, MPa;
σ v is the original vertical ground stress, MPa;
gamma is the fault inclination angle;
Beta is the included angle between the fault trend and the horizontal maximum ground stress, and DEG;
delta is a safety coefficient, and is dimensionless;
s5: calculating a hydraulic fracture net pressure value under the initial fracturing design scheme, comparing the hydraulic fracture net pressure value with a safe construction net pressure value, and executing according to the initial fracturing design scheme when the hydraulic fracture net pressure value is smaller than the safe construction net pressure value; when the net pressure value of the hydraulic fracture is larger than the net pressure value of the safety construction, an initial fracturing design scheme is adjusted;
s6: when the hydraulic fracture net pressure value is larger than the safe construction net pressure value, calculating a safe fracturing construction parameter value corresponding to the safe construction net pressure value in the step S4, and adjusting an initial fracturing design scheme according to the corresponding safe fracturing construction parameter value;
s7: and constructing according to the modified fracturing design scheme.
2. The shale oil and gas reservoir volume fracturing design method for preventing fault activation according to claim 1, wherein the shale oil and gas reservoir volume fracturing design method is characterized in that: in the step S1, the distance between the intersection point of the fault and the horizontal shaft and the adjacent perforation cluster is set as an avoiding distance, the well cementation quality is determined according to the sound amplitude variable density well logging result, the avoiding distance is 15m when the well cementation quality is good, the avoiding distance is 20m when the well cementation quality is medium, and the avoiding distance is 25m when the well cementation quality is poor.
3. The shale oil and gas reservoir volume fracturing design method for preventing fault activation according to claim 1, wherein the shale oil and gas reservoir volume fracturing design method is characterized in that: in the step S5, a specific formula for calculating the net pressure value of the hydraulic fracture in the initial fracturing design scheme is as follows:
In the above formula, P net is the net pressure value of the hydraulic fracture under the initial fracturing design scheme and MPa;
e is the Young's modulus of stratum rock and Pa;
v is the stratum rock poisson ratio, dimensionless;
Q 0 is single-stage injection displacement when the horizontal well is fractured in stages, and m 3/s;
n is the number of single-section perforation clusters in staged fracturing of the horizontal well, and is dimensionless;
Mu is the viscosity of the fracturing fluid and Pa.s;
h f is hydraulic fracture height, m;
t is the total construction time, s.
4. A shale reservoir volume fracturing design method for preventing fault activation according to claim 3, wherein: in the step S6, the safe fracturing construction parameters are calculated according to the safe net pressure value calculated in the step S4, and the specific process is as follows:
When the same viscosity fracturing fluid is adopted for construction on site, the safety discharge capacity is obtained, and the specific formula is as follows:
when the same displacement construction is adopted on site, the viscosity of the safe fracturing fluid is calculated, and the specific formula is as follows:
And adjusting an initial fracturing design scheme according to the field condition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202410065340.6A CN117709125B (en) | 2024-01-16 | Shale oil and gas reservoir volume fracturing design method capable of preventing fault activation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410065340.6A CN117709125B (en) | 2024-01-16 | Shale oil and gas reservoir volume fracturing design method capable of preventing fault activation |
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| Publication Number | Publication Date |
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| CN117709125A CN117709125A (en) | 2024-03-15 |
| CN117709125B true CN117709125B (en) | 2024-06-25 |
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Non-Patent Citations (2)
| Title |
|---|
| 非均质储层水平井分段压裂设计及应用;王世泽;;钻采工艺;20170325(第02期);全文 * |
| 非常规油气藏缝网压裂裂缝扩展数值模拟研究;许文俊;CNK博士电子期刊;20231015;全文 * |
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