A three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fracture-vug body

Abstract

The present application relates to the technical field of oil and gas exploration and development, and particularly discloses a three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fracture-vug body, which is based on the pore thermal-elasticity mechanics theory and the near-state of pore fluid in the overpressure system of deep carbonate rock formation, and establishes a pore pressure prediction model for the carbonate rock formation by considering the fracture-vug development interpreted by imaging logging; by introducing the empirical coefficient of pore pressure in the target area, a pore pressure prediction model suitable for the target area is obtained; the pore pressure prediction model for the target area establishes an initial three-dimensional pore pressure body, and constructs a fracture body and a three-dimensional temperature field for the target area, and the initial three-dimensional pore pressure body is corrected by the fracture body and the three-dimensional temperature field in turn. The present application solves the problems of low prediction accuracy in fracture development zone and neglecting the non-uniform distribution of formation temperature field in space and its continuous influence on pore pressure by conventional methods, and improves the pore pressure prediction accuracy for carbonate rock formation.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration and development technology, specifically relating to a three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fractured cavity. Background Technology

[0002] Carbonate formations are rich in oil and gas resources, but their strong heterogeneity (especially the development of fractures and caverns) makes formation pore pressure prediction a global challenge. Traditional prediction methods (Eaton method, Bowers method) are based on the undercompaction theory of clastic rocks, which results in large errors when applied to carbonate formations, making them unsuitable. While current 3D seismic prediction technology can achieve pre-drilling prediction, its low resolution fails to capture local pressure abrupt changes caused by fracture development, leading to generally low prediction values ​​in fracture zones and posing significant risks to drilling safety. Secondly, existing formation pressure prediction technologies lack effective models for overpressure mechanisms such as fluid expansion in carbonate formations and neglect the impact of fracture development, a key geological factor, on pore pressure. Furthermore, existing 3D pore pressure prediction methods often ignore the spatial non-uniform distribution of the formation temperature field and its continuous influence on pore pressure, especially in areas with active thermal fluids in carbonate rocks, where temperature changes significantly alter pore pressure distribution. Therefore, we propose a 3D pre-drilling pore pressure prediction method that considers the temperature field and fracture / cavity structures. Summary of the Invention

[0003] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a three-dimensional pre-drilling prediction method for pore pressure that considers temperature field and fracture cavities. This method can solve the problem that conventional seismic prediction methods cannot accurately predict local pore pressure in fracture development zones, thereby improving the prediction accuracy of pore pressure in carbonate rock formations.

[0004] The technical solution adopted in this invention is: a three-dimensional pre-drilling prediction method considering temperature field and pore pressure in fractured cavities, comprising the following steps:

[0005] Step 1: Based on the theory of porosity thermoelasticity, the effect of temperature is considered in the stress-strain constitutive equation of saturated fluid porous media to establish a linear porosity thermoelastic constitutive equation.

[0006] ,

[0007] in, For the corresponding force tensor of the solid; Lamé coefficient; The symbol for the Kronecker function; For solid strain; For the corresponding shear modulus; The strain of the fluid in the pores; The bulk modulus of the rock; The coefficient of thermal expansion of the rock skeleton represents the amount of stress change caused by a change in the rock skeleton under a unit temperature. Formation temperature; Formation pore pressure; These are the material constitutive coefficients; The Biot modulus characterizes the ease with which a pore fluid can be compressed under stress. The coefficient of thermal expansion of pore fluid is used to characterize the pressure change caused by a unit temperature change in rock pore fluid.

[0008] Since the pore fluid in the overpressure system of deep carbonate formations is in a nearly closed state, i.e., considered as an undrained system, the change in fluid volume within the carbonate rock is zero. Therefore, the constitutive coefficient of the material and the thermal expansion coefficient of the pore fluid are not considered when calculating the formation pore pressure. ,but

[0009] ,

[0010] Among them, solid strain Constitutive coefficient of material ,but

[0011] ,

[0012] in, For Biot coefficient, For the confining pressure of the rock, The bulk modulus of saturated rock;

[0013] Biot modulus ;

[0014] Because carbonate rocks have a strong rigid framework, i.e., the bulk modulus of the rock matrix is... Much greater than the bulk modulus of saturated rock and the bulk modulus of the mixed fluid The simplified formula for calculating the Biot modulus is:

[0015]

[0016] in, Porosity The bulk modulus of the mixture fluid. Bulk modulus of the rock matrix;

[0017] Among them, the Biot coefficient ,but

[0018]

[0019] in, The bulk modulus of the rock skeleton;

[0020] Step 2: Considering the fracture and vulcanization development interpreted by imaging logging, fit the relationship between the porosity compliance factor and the fracture and vulcanization development index to obtain...

[0021] ,

[0022] in, Pore ​​compliance factor This refers to the crack development index. is the cave development index, where a, b, and c are all fitting coefficients;

[0023] The relationship between the bulk modulus of the rock skeleton and the bulk modulus of the rock matrix can then be obtained through the porosity compliance factor.

[0024] ;

[0025] Step 3: Establish a pore pressure prediction model for carbonate rock formations that considers the effects of pore structure and temperature, based on Steps 1 and 2, to provide a basis for... After deformation, the result is

[0026]

[0027] Step 4: For the target area to be predicted, the elasticity change term in Step 3 can be rewritten to obtain...

[0028] ,

[0029] in, It is a composite elastic parameter, which incorporates the elastic properties of the rock skeleton and pore fluid;

[0030] Since the theoretical model is derived based on the linear elastic relationship of porous media, actual formation rocks often exhibit nonlinear elastic properties and energy dissipation. Therefore, to better apply this pore pressure prediction theoretical model, it is necessary to correct its calculation errors by introducing empirical coefficients for pore pressure in the target region to be predicted. empirical coefficient The pore pressure prediction model is obtained by back-calculating the measured pore pressure values ​​within the target area, thus yielding a model suitable for the target area.

[0031] ;

[0032] Step 4: Process all drilled wells in the target area according to the pore pressure prediction model of the target area to obtain the pore pressure data of each drilled well.

[0033] Step 5: Based on single-well pore pressure data, combined with seismic data, stacked velocity spectrum data, stratigraphic data and well logging data in the target area, three-dimensional interpolation is performed using the effective stress method to obtain the initial three-dimensional pore pressure volume, which is used for three-dimensional prediction of the target area.

[0034] Step 6: Obtain the fracture development index volume of the target area, and obtain the fracture correction coefficient by comparing the formation pore pressure coefficient, fracture development index and single well pore pressure data before fracture correction through regression analysis. Then, correct the initial three-dimensional pore pressure volume using the fracture development volume and the fracture correction coefficient.

[0035] Step 7: Establish a three-dimensional temperature field in the target area, and obtain the temperature-pressure coupling coefficient by regression fitting of the measured pore pressure of each drilled well in the target area with the corresponding temperature data at the time of measurement. Then, use the temperature-pressure coupling coefficient in the three-dimensional temperature field to perform a second correction on the initial three-dimensional pore pressure body after the first correction by the fracture development body and the fracture correction coefficient. After correction, obtain the three-dimensional pore pressure body that reflects the influence of fracture development and temperature field in the target area.

[0036] Step 8: Predict the pre-drilling pore pressure at the well site in the target area by using a three-dimensional pore pressure body that reflects the influence of fracture development and temperature field in the target area.

[0037] Preferably, obtaining the crack development index in step 6 includes the following steps:

[0038] Step A1: Interpret fractures using a combined well-seismic analysis, obtain fracture density for each well using imaging logging, and calculate the fracture development index for each well. The calculation formula is as follows:

[0039]

[0040] in, For well depth Crack development density at the location, For well depth Fracture density at a point half the length of the well section pointing upwards or to the left. For well depth Fracture density at a point half the length of the well section pointing downwards or to the right. The length of the well section. For well depth Crack development index at the location, To achieve the minimum crack development density, This represents the maximum crack development density.

[0041] Step A2: Obtain the three-dimensional fracture structure of the target area using seismic data from the target area;

[0042] Step A3: The fracture development index of a single well is obtained by co-kriging interpolation and the lateral distribution of the three-dimensional fracture body constrained interpolation results.

[0043] Preferably, in step 6, the initial three-dimensional pore pressure body is corrected once using the fracture development body and the fracture correction coefficient as follows:

[0044] ,

[0045] in, Pore ​​pressure before crack repair Pore ​​pressure after crack repair This is the crack correction factor. This represents the crack development index.

[0046] Preferably, in step 7, the initial three-dimensional pore pressure body, after being corrected once by the fracture development body and the fracture correction coefficient, is further corrected using the temperature-pressure coupling coefficient in the three-dimensional temperature field as follows:

[0047] ,

[0048] in, The three-dimensional pore pressure is corrected for cracks and temperature. Pore ​​pressure after crack repair This is the temperature-pressure coupling coefficient. This represents the formation temperature at the corresponding spatial point within the target region. The average ground temperature of the target area.

[0049] The beneficial effects of this invention are as follows: Based on the theory of pore thermoelasticity and combined with the main controlling factors of carbonate rock overpressure formations, this invention constructs a pore pressure prediction model suitable for carbonate rock formations. It fully considers the influence of fracture development and temperature on the prediction of pore pressure in carbonate rock formations, introduces the fracture development index and temperature-pressure coupling coefficient, further improves the prediction accuracy of pore pressure in carbonate rock formations, and combines the effective stress method to obtain the initial pore pressure volume of the target area, realizing the transformation from one-dimensional prediction to multi-dimensional prediction of pore pressure in carbonate rock formations. Attached Figure Description

[0050] Figure 1 This is a flowchart of the present invention;

[0051] Figure 2 This is a comparison chart of the predicted pore pressure profile of a single well in an embodiment of the present invention.

[0052] Figure 3 This is a high-precision velocity volume result diagram in an embodiment of the present invention;

[0053] Figure 4 This is a planar prediction result of the crack development index, taking the Feixianguan Formation as an example in this embodiment of the invention;

[0054] Figure 5 This is a diagram showing the three-dimensional pore pressure plane prediction results before and after correction, taking the Feixianguan Formation as an example in this embodiment of the invention. Detailed Implementation

[0055] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0056] Example

[0057] like Figure 1 As shown, the three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fractured cavity provided in this embodiment includes the following steps:

[0058] Step 1: Based on the theory of porosity thermoelasticity, the effect of temperature is considered in the stress-strain constitutive equation of saturated fluid porous media to establish a linear porosity thermoelastic constitutive equation.

[0059] ,

[0060] in, For the corresponding force tensor of the solid; Lamé coefficient; The symbol for the Kronecker function; For solid strain; For the corresponding shear modulus; The strain of the fluid in the pores; The bulk modulus of the rock; The coefficient of thermal expansion of the rock skeleton represents the amount of stress change caused by a change in the rock skeleton under a unit temperature. Formation temperature; Formation pore pressure; These are the material constitutive coefficients; The Biot modulus characterizes the ease with which a pore fluid can be compressed under stress. The coefficient of thermal expansion of pore fluid is used to characterize the pressure change caused by a unit temperature change in rock pore fluid.

[0061] Since the pore fluid in the overpressure system of deep carbonate formations is in a nearly closed state, i.e., considered as an undrained system, the change in fluid volume within the carbonate rock is zero. Therefore, the constitutive coefficient of the material and the thermal expansion coefficient of the pore fluid are not considered when calculating the formation pore pressure. ,but

[0062] ,

[0063] Among them, solid strain Constitutive coefficient of material ,but

[0064] ,

[0065] in, For Biot coefficient, For the confining pressure of the rock, The bulk modulus of saturated rock;

[0066] Biot modulus ;

[0067] Because carbonate rocks have a strong rigid framework, i.e., the bulk modulus of the rock matrix is... Much greater than the bulk modulus of saturated rock and the bulk modulus of the mixed fluid The simplified formula for calculating the Biot modulus is:

[0068]

[0069] in, Porosity The bulk modulus of the mixture fluid. Bulk modulus of the rock matrix;

[0070] Among them, the Biot coefficient ,but

[0071]

[0072] in, The bulk modulus of the rock skeleton;

[0073] Step 2: Considering the fracture and vulcanization development interpreted by imaging logging, fit the relationship between the porosity compliance factor and the fracture and vulcanization development index to obtain...

[0074] ,

[0075] in, Pore ​​compliance factor This refers to the crack development index. is the cave development index, where a, b, and c are all fitting coefficients;

[0076] The relationship between the bulk modulus of the rock skeleton and the bulk modulus of the rock matrix can then be obtained through the porosity compliance factor.

[0077] ;

[0078] Step 3: Establish a pore pressure prediction model for carbonate rock formations that considers the effects of pore structure and temperature, based on Steps 1 and 2, to provide a basis for... After deformation, the result is

[0079]

[0080] Step 4: For the target area to be predicted, the elasticity change term in Step 3 can be rewritten to obtain...

[0081] ,

[0082] in, It is a composite elastic parameter, which incorporates the elastic properties of the rock skeleton and pore fluid;

[0083] Since the theoretical model is derived based on the linear elastic relationship of porous media, actual formation rocks often exhibit nonlinear elastic properties and energy dissipation. Therefore, to better apply this pore pressure prediction theoretical model, it is necessary to correct its calculation errors by introducing empirical coefficients for pore pressure in the target region to be predicted. empirical coefficient The pore pressure prediction model is obtained by back-calculating the measured pore pressure values ​​within the target area, thus yielding a model suitable for the target area.

[0084] ;

[0085] In this embodiment, the Feixianguan Formation carbonate rock overpressure strata in the TH region of the Sichuan Basin were selected as the target area, and the longitudinal wave velocity Vp and transverse wave velocity Vs of the rocks in the target area were measured using an acoustic wave testing system.

[0086] Table 1 shows the basic physical properties of overpressured carbonate rock samples from the Feixianguan Formation in the TH region of the Sichuan Basin.

[0087] Table 1

[0088] strata Diameter / mm Height / mm Density (g / cm3) Porosity / % Permeability / (10-3μm2) Feixian Pass Group 24.66 50.18 2.661 0.613 0.0000158

[0089] Table 2 shows the longitudinal and transverse wave velocities of rock samples from the Feixianguan Formation in the TH area of ​​the Sichuan Basin under different effective stresses.

[0090] Table 2

[0091] Effective stress / MPa <![CDATA[V p / (m / s)]]> <![CDATA[V s / (m / s)]]> E / GPa Poisson's ratio 0 5186.03 2838.24 55.15 0.286 2 5203.24 2857.63 55.813 0.284 5 5211.88 2870.71 56.246 0.282 10 5255.55 2869.4 56.432 0.288 15 5255.55 2901.25 57.386 0.281 20 5264.37 2898.57 57.353 0.282 25 5282.11 2901.25 57.527 0.284 30 5345.12 2920.16 58.429 0.287 35 5372.59 2936.56 59.074 0.287 40 5428.39 2953.15 59.874 0.29 45 5485.35 2954.55 60.202 0.296 50 5475.77 2978.4 60.907 0.29 55 5504.61 2984.06 61.234 0.292 60 5543.53 2986.9 61.519 0.295 65 5543.53 2995.46 61.793 0.294

[0092] Step 4: Process all drilled wells in the target area according to the pore pressure prediction model of the target area to obtain the pore pressure data of each drilled well. In actual operation, it is only necessary to process multiple drilled wells in the target area. That is, in this embodiment, the empirical coefficient of pore pressure in the TH area of ​​the Sichuan Basin is obtained to obtain a pore pressure prediction model suitable for the TH area of ​​the Sichuan Basin. The pore pressure prediction model suitable for the TH area of ​​the Sichuan Basin is used to predict the pore pressure of the Feixianguan Formation, Changxing Formation, Maokou Formation and Qixia Formation of well PT101 in the area, and obtain the pore pressure of each well in these four groups. A high-precision pore pressure prediction curve of well PT101 is obtained, and a pore pressure profile is drawn. The drawn pore pressure profile is compared with the conventional multi-parameter method, such as... Figure 2 As shown;

[0093] Step 5: Based on single-well pore pressure data, combined with seismic data, stacked velocity spectrum data, stratigraphic data, and well logging data within the target area, three-dimensional interpolation is performed using the effective stress method to obtain the initial three-dimensional pore pressure volume. In this embodiment, seismic data, stacked velocity spectrum data, stratigraphic data, and well logging data of the TH region in the Sichuan Basin are acquired. In the geological software, the single-well pore pressure data predicted in Step 4 is used as the basic data. Combined with the seismic data, stacked velocity spectrum data, stratigraphic data, and well logging data of the TH region in the Sichuan Basin, a three-dimensional seismic velocity volume of the TH region in the Sichuan Basin is established, such as... Figure 3 As shown, the effective stress method is then used to perform three-dimensional interpolation to generate the initial three-dimensional pore pressure body;

[0094] Step 6: Obtain the crack development index of the target area, including the following steps:

[0095] Step A1: Interpret fractures using a combined well-seismic analysis, obtain fracture density for each well using imaging logging, and calculate the fracture development index for each well. The calculation formula is as follows:

[0096]

[0097] in, For well depth Crack development density at the location, For well depth Fracture density at a point half the length of the well section pointing upwards or to the left. For well depth Fracture density at a point half the length of the well section pointing downwards or to the right. The length of the well section. For well depth Crack development index at the location, To achieve the minimum crack development density, This represents the maximum crack development density.

[0098] Step A2: Acquire seismic data of the target area, and perform denoising, structural smoothing, and multiple tracking of ant bodies on the seismic data to obtain the three-dimensional fracture body of the target area;

[0099] Step A3: The fracture development index of a single well is obtained by co-kriging interpolation and the lateral distribution results of the three-dimensional fracture body constrained interpolation results are used to obtain the fracture development index volume of the target area.

[0100] In this embodiment, the Feixianguan Formation is used as an example to draw a planar diagram of the crack development index, such as... Figure 4 As shown;

[0101] Step 6 further involves comparing the formation pore pressure coefficient, fracture development index, and single-well pore pressure data before fracture correction, performing regression analysis to obtain the fracture correction coefficient, and then correcting the initial three-dimensional pore pressure body using the fracture development body and the fracture correction coefficient; that is, introducing the fracture development index into the initial three-dimensional pore pressure body, thereby using the fracture development index and the fracture correction coefficient to correct the initial three-dimensional pore pressure body, and obtaining a three-dimensional pore pressure body that can accurately reflect the pressure anomaly in the fracture development zone.

[0102] ,

[0103] in, Pore ​​pressure before crack repair Pore ​​pressure after crack repair This is the crack correction factor. The crack development index;

[0104] Step 7: Based on well logging temperature data, geothermal gradient model, and three-dimensional velocity volume obtained from seismic inversion, establish a three-dimensional temperature field for the target area. Introduce the three-dimensional temperature field into the initial three-dimensional pore pressure volume to achieve spatial coupling correction between the three-dimensional temperature field and the initial three-dimensional pore pressure volume. Obtain the temperature-pressure coupling coefficient by regression fitting of the measured pore pressure and the corresponding temperature data of each drilled well in the target area. Use the temperature-pressure coupling coefficient in the three-dimensional temperature field to perform a second correction on the initial three-dimensional pore pressure volume after the first correction by the fracture development body and fracture correction coefficient. After correction, obtain a three-dimensional pore pressure volume that simultaneously reflects the influence of fracture development and temperature field in the target area.

[0105] ,

[0106] in, The three-dimensional pore pressure is corrected for cracks and temperature. Pore ​​pressure after crack repair This is the temperature-pressure coupling coefficient. This represents the formation temperature at the corresponding spatial point within the target region. The average ground temperature of the target area;

[0107] In this embodiment, the Feixianguan Formation of Well PT101 is used as an example to plot the pore pressure prediction plane before and after correction. The results are as follows: Figure 5 As shown;

[0108] Step 8: Predict the pre-drilling pore pressure at the well site in the target area by using a three-dimensional pore pressure body that reflects the influence of fracture development and temperature field in the target area.

[0109] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and substitutions based on the technical solutions and inventive concepts provided by the present invention should be covered within the scope of protection of the present invention.

Claims

1. A three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fractured cavity, characterized in that: Includes the following steps: Step 1: Based on the theory of pore thermoelasticity, establish the linear pore thermoelastic constitutive equation. ， in, For the corresponding force tensor of the solid, The Lamé coefficient is given. Represents the Kronecker function symbol. For solid strain, For the corresponding shear modulus, The strain of the fluid in the pores. For the bulk modulus of rock, The coefficient of thermal expansion of the rock skeleton. For the formation temperature, For formation pore pressure, The constitutive coefficient of the material. For Biot modulus, The coefficient of thermal expansion of the pore fluid; Based on the fact that the pore fluid in the overpressure system of carbonate formations is in a near-closed state, and the change in fluid volume within the carbonate rock is zero, meaning that fluid strain and the thermal expansion coefficient of the pore fluid are not considered when calculating formation pore pressure, then... ， Among them, solid strain Constitutive coefficient of material ,but ， in, For Biot coefficient, For the confining pressure of the rock, The bulk modulus of saturated rock; Since carbonate rocks have a strong rigid framework, the formula for calculating the Biot modulus can be simplified to: in, Porosity The bulk modulus of the mixture fluid. Bulk modulus of the rock matrix; Among them, the Biot coefficient ,but in, The bulk modulus of the rock skeleton; Step 2: Considering the fracture and vulcanization development interpreted by imaging logging, fit the relationship between the porosity compliance factor and the fracture and vulcanization development index to obtain... ， in, Pore ​​compliance factor This refers to the crack development index. is the cave development index, where a, b, and c are all fitting coefficients; The relationship between the bulk modulus of the rock skeleton and the bulk modulus of the rock matrix can then be obtained through the porosity compliance factor. ； Step 3: Establish a pore pressure prediction model for carbonate rock formations that considers the effects of pore structure and temperature, based on Steps 1 and 2, to provide a basis for... Step 4: For the target area to be predicted, the elasticity change term in Step 3 can be rewritten to obtain... ， in, For composite elastic parameters; Introduce empirical coefficients for pore pressure within the target region to be predicted. A pore pressure prediction model suitable for the target region is obtained. ； Step 4: Process all drilled wells in the target area according to the pore pressure prediction model of the target area to obtain the pore pressure data of each drilled well. Step 5: Based on the pore pressure data of a single well, combined with seismic data, stacked velocity spectrum data, stratigraphic data and well logging data in the target area, three-dimensional interpolation is performed using the effective stress method to obtain the initial three-dimensional pore pressure volume; Step 6: Obtain the fracture development index volume of the target area, and obtain the fracture correction coefficient by comparing the formation pore pressure coefficient, fracture development index and single well pore pressure data before fracture correction through regression analysis. Then, correct the initial three-dimensional pore pressure volume using the fracture development volume and the fracture correction coefficient. Step 7: Establish a three-dimensional temperature field in the target area, and obtain the temperature-pressure coupling coefficient by regression fitting of the measured pore pressure of each drilled well in the target area with the corresponding temperature data at the time of measurement. Then, use the temperature-pressure coupling coefficient in the three-dimensional temperature field to perform a second correction on the initial three-dimensional pore pressure body after the first correction by the fracture development body and the fracture correction coefficient. After correction, obtain the three-dimensional pore pressure body that reflects the influence of fracture development and temperature field in the target area. Step 8: Predict the pre-drilling pore pressure at the well site in the target area by using a three-dimensional pore pressure body that reflects the influence of fracture development and temperature field in the target area.

2. The three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fracture cavity as described in claim 1, characterized in that: Step 6, obtaining the crack development index, includes the following steps: Step A1: Interpret fractures using a combined well-seismic analysis, obtain fracture density for each well using imaging logging, and calculate the fracture development index for each well. The calculation formula is as follows: in, For well depth Crack development density at the location, For well depth Fracture density at a point half the length of the well section pointing upwards or to the left. For well depth Fracture density at a point half the length of the well section pointing downwards or to the right. The length of the well section. For well depth Crack development index at the location, To achieve the minimum crack development density, This represents the maximum crack development density. Step A2: Obtain the three-dimensional fracture structure of the target area using seismic data from the target area; Step A3: The fracture development index of a single well is obtained by co-kriging interpolation and the lateral distribution of the three-dimensional fracture body constrained interpolation results.

3. A three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fractured cavity as described in claim 1 or 2, characterized in that: In step 6, the initial three-dimensional pore pressure volume is corrected using the fracture development body and the fracture correction factor as follows: ， in, Pore ​​pressure before crack repair Pore ​​pressure after crack repair This is the crack correction factor. This represents the crack development index.

4. The three-dimensional pre-drilling prediction method for pore pressure considering temperature field and fractured cavity as described in claim 3, characterized in that: In step 7, the initial three-dimensional pore pressure volume, after being corrected once by the fracture development body and the fracture correction coefficient, is further corrected using the temperature-pressure coupling coefficient in the three-dimensional temperature field as follows: ， in, The three-dimensional pore pressure is corrected for cracks and temperature. Pore ​​pressure after crack repair This is the temperature-pressure coupling coefficient. This represents the formation temperature at the corresponding spatial point within the target region. The average ground temperature of the target area.

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