CN115324556A

CN115324556A - Comprehensive prediction method for fracture-induced deformation risk level of oil-gas casing

Info

Publication number: CN115324556A
Application number: CN202110454838.8A
Authority: CN
Inventors: 陈明忠; 朱炬辉; 马思平; 石孝志; 齐天俊; 邹龙庆; 殷晟
Original assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Current assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2022-11-11

Abstract

The invention provides a comprehensive prediction method for the fracture-induced deformation risk level of an oil-gas casing, which comprises the following steps: establishing a block fine geostress field; establishing a geological-fracturing engineering-cement sheath-casing integrated finite element model, and calculating the initial stress distribution of the casing string before fracturing; calculating the variation of the ground stress field after the reservoir fracturing and the stress distribution of the casing column; performing casing deformation analysis of the horizontal well by combining geology, well cementation and casing; predicting the position of the casing deformation induced by the fracturing according to the casing deformation analysis result; and defining risk factors influencing the deformation of the casing, and judging the risk level of the fracture-induced casing deformation according to the number of the risk factors existing in the casing. The method can identify and determine the size of the existing deformation risk of the casing before and during fracturing and predict the region position of the risk point.

Description

Comprehensive prediction method for fracture-induced deformation risk level of oil-gas casing

Technical Field

The invention relates to the technical field of shale gas development, in particular to a comprehensive prediction method for the deformation risk level of a fracturing-induced oil-gas casing.

Background

Shale gas geological structures in high stress areas such as Sichuan basins and similar structures in China are complex, the maximum horizontal main stress of a reservoir is close to or even higher than the pressure of overlying rocks, the probability of casing deformation is relatively high under the influence of various factors and multi-factor superposition, and the fracturing process is the most intuitive embodiment.

In the prior art, although research on related casing deformation is carried out at home and abroad, single factors are mostly adopted, geological factors are emphasized, design factors are emphasized, the formed conclusion is single and limited, and the accuracy of predicting the casing deformation position is not high. For example, patent application publication No. CN 105760564A, entitled method and apparatus for analyzing casing failure in 2016, 7, 13, describes a method and apparatus for analyzing casing failure in an oil reservoir, which determines information of a risk high-occurrence region of a casing of a target oil and gas well according to seismic parameters and engineering parameters, thereby obtaining dynamic changes of geostress and deformation conditions of a rock stratum in a fracturing process of a stratum belonging to the risk high-occurrence region of the casing, and determining the production state of casing deformation. Although the method can be used for analyzing the failure of the oil layer casing under the condition of large-scale segmental volume fracturing, the method is not suitable for predicting the casing deformation generated in the fracturing reformation of the shale reservoir. A method for predicting sleeve change points by using seismic data is disclosed in patent application document CN 110485993A, which is published on 11/12/2019, and the method comprises the steps of performing high-resolution processing and fine horizon comparison on the seismic data, then obtaining formation curvature, calculating amplitude difference and micro-amplitude folding amount, finally picking up possible sleeve change point positions and micro-amplitude folding degree from the micro-amplitude folding amount data according to well track coordinates, and extracting the micro-amplitude folding amount along a horizontal well track to obtain a casing point prediction result. Although the method can quickly process the seismic data to predict the casing change point of the horizontal well, the analyzed logging data is single, the seismic data is easily interfered by geological factors, the analysis result has certain errors, and the accuracy of predicting the casing change point cannot be judged.

The mining scale of shale gas in a high geostress area is not very large internationally, and related researches on the fracturing induced casing deformation in the area are less, so that the accuracy of predicting the casing deformation is low.

Therefore, it is necessary to form a comprehensive prediction method capable of identifying and determining the size of the existing casing deformation risk and determining the region position of the risk point before the fracturing construction, so as to provide feasible technical measures and develop a casing deformation prediction and prevention technical scheme.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide an integrated prediction method that can predict the risk level of fracture-induced deformation of a hydrocarbon casing before and during fracturing.

In order to achieve the purpose, the invention provides a comprehensive prediction method of the fracture-induced deformation risk level of a hydrocarbon casing, which comprises the following steps: acquiring a single-well geological analysis result and a maximum horizontal principal stress direction angle based on the logging data of a target block, and establishing a block fine geostress field; establishing a geological-fracturing engineering-cement sheath-casing integrated finite element model based on the block fine geostress field, and performing three-dimensional finite element deformation and stress analysis on the casing string in the full horizontal section of the horizontal well to obtain the initial stress distribution of the casing string before fracturing; carrying out three-dimensional finite element deformation and stress analysis on the casing string subjected to reservoir fracturing, calculating the change of a ground stress field caused by fracturing, and finding out the position distribution of applying a shear load to the casing string; performing geological-well cementation-casing combined integrated casing deformation analysis on the horizontal well, wherein the analysis comprises gamma curve distribution analysis on a horizontal section of a well track, well cementation quality and sound amplitude curve distribution analysis on the horizontal section of the well track, fracturing construction pressure curve analysis on the horizontal section of the well track, microseism monitoring result analysis on the horizontal well and simulation calculation of the change analysis of the shearing force outside a shaft of the horizontal section of the well track; predicting the positions of the fracture-induced casing deformation according to the casing deformation analysis result, wherein the positions of the casing deformation comprise the positions of local abnormal bulges of a gamma curve, the positions of well cementation homogeneity abnormity, the maximum shear load point caused by a fracture section where a construction pressure peak value is positioned, and the outer edge of a stratum fracture area caused by fracturing; judging the risk level of the deformation of the casing induced by the fracturing according to the number of risk factors existing in the casing, wherein the risk factors comprise a fracturing construction pressure curve sand blocking peak, natural gamma local abnormal change, well cementation homogeneity local abnormal change and the overlapping of a defect point of the natural gamma local abnormal change and a defect point of the well cementation homogeneity local abnormal change; for the casings with the same size, when the thickness of the casing is less than 11mm, the number of risk factors is 0, the risk level is none, when the number of risk factors is 1, the risk level is the first level (or called as medium), when the number of risk factors is 2, the risk level is the second level (or called as large), when the number of risk factors is 3 or 4, the risk level is the third level (or called as large), and the third level is higher than the first level; when the thickness of the casing is larger than 11mm, the risk factor number is 0, the risk level is none, when the risk factor number is 1, the risk level is the first level (or called as medium), when the risk factor number is 2 or 3, the risk level is the second level (or called as large), when the risk number is 4, the risk level is the third level (or called as large), and the third level is higher than the second level and is higher than the first level. Equivalently, when the fracture inducing casing deformation risk level is judged by the number of risk factors present in the casing, the greater the number of risk factors, the higher the fracture inducing casing deformation risk, at a predetermined casing size and thickness.

In an exemplary embodiment of the invention, said establishing a block-wise stress field may comprise the steps of: according to a technical method of 'well-seismic combination', on the basis of seismic wave data, a three-dimensional geological model of a target block is established by combining single-well horizon information; calculating rock mechanical parameters according to the logging data of a single well in the target block, and performing single-well geomechanical analysis on other logging data and the rock mechanical parameters to obtain a single-well geomechanical analysis result; comprehensively analyzing information of a world stress map, single well measurement information of existing wells and horizontal well fracturing microseism monitoring information in a target block to obtain a maximum horizontal principal stress direction angle in the target block; introducing a three-dimensional geological model, establishing a finite element model of the geostress field of a target block, verifying the simulation result of the geostress field of the target block based on the single well geological analysis result and the actual measurement result of the microseism of the existing well during the fracturing construction period, and constructing a block fine geostress field by solving the numerical value of the geostress field qualified through verification.

In an exemplary embodiment of the present invention, the building a three-dimensional geological model of the target block based on the seismic wave data and in combination with the single-well horizon information may include: and establishing the grid geometric dimension of a geological model according to the three-dimensional seismic wave data, dividing the stratum and defining the size of grid units of each stratum, wherein the grid units of the stratum where the reservoir is located are smaller than those of other strata.

In an exemplary embodiment of the present invention, a ratio of the grid cell thickness of the formation in which the reservoir is located to the grid cell thickness of the other formation may be 1:18 to 1:30.

in an exemplary embodiment of the invention, the other well log data may include gamma ray, compressional acoustic time length and density of the formation, and the rock mechanics parameters may include Young's modulus, poisson's ratio, cohesion and internal friction angle.

In an exemplary embodiment of the invention, the single well geological analysis may include geostress results obtained by indirect analysis using other well log data and geostress results obtained by direct calculation using rock mechanics parameters.

In an exemplary embodiment of the present invention, the comprehensively analyzing information of the world stress map, information of single well survey of existing wells, and information of horizontal well fracture micro-seismic monitoring in the target block to obtain a maximum horizontal principal stress direction angle in the target block may include: judging the maximum horizontal principal stress direction angle of the area to which the target block belongs by using a world stress map, and determining the interval range to which the maximum horizontal principal stress direction angle in the target block belongs; according to the information measured by the single well, the range of the maximum horizontal principal stress direction angles of different structural parts in the target block is judged, and the change rule of the maximum horizontal principal stress direction angles in the target block along with the terrain is determined; and analyzing the microseism monitoring information, verifying and correcting the value of the maximum horizontal principal stress direction angle in the target block summarized by using the world stress map and the single-well measurement information by combining the analysis result of the microseism monitoring information, and/or supplementing and correcting the value of the maximum horizontal principal stress direction angle in the target block of the leakage area lost by using the world stress map and the single-well measurement information.

In an exemplary embodiment of the present invention, the establishing a ground stress field finite element model of the target block may include: setting units adopted by a geological model grid as three-dimensional 8-node linear units, setting the load of a ground stress field finite element model as a gravity load, setting boundary conditions of four sides and the bottom of the ground stress field finite element model as normal displacement constraints, setting boundary conditions of the top of the ground stress field finite element model as free boundaries, and setting initial ground stress parameters and initial pore pressure parameters as initial conditions, wherein the initial ground stress parameters comprise three-axis ground stress main components and a maximum horizontal main stress direction angle obtained by single-well geomechanical analysis.

In an exemplary embodiment of the invention, verifying a simulation result of a target block geostress field based on a single well geological analysis result and a microseism actual measurement result of an existing well during fracturing construction, and constructing a block fine geostress field by using a numerical solution of the qualified geostress field, may include: for each single well of the target block, respectively utilizing the crustal stress result obtained by indirectly analyzing other logging data and the crustal stress result obtained by directly calculating rock mechanical parameters as initial crustal stress parameters to carry out numerical simulation on the crustal stress field of the target block to obtain a corresponding crustal stress field numerical solution; and comparing the two kinds of numerical solutions of the geostress field with the errors of the actual measurement values of the geostress field of the existing well fracturing construction, and taking the numerical solution with a smaller error with the actual measurement values of the geostress field as the block fine geostress field.

In an exemplary embodiment of the present invention, the local abnormal protrusion of the gamma curve may be determined according to a local gamma value greater than 200GAPI.

In an exemplary embodiment of the present invention, the determination criterion of the well cementation homogeneity abnormality may be that the local acoustic amplitude is higher than the interface with poor cement cementation and the result of the local evaluation of the well cementation quality is poor.

In an exemplary embodiment of the invention, the maximum shear load point caused by the fracture zone where the construction pressure peak value is located may be determined according to that the amplitude of the pressure curve surge or dip is greater than 10MPa/min, and the pressure curve is not a straight line.

In an exemplary embodiment of the invention, the location of the fracture of the formation caused by the fracture may be determined by pre-fracture geological data and/or numerical simulation of the reservoir fracture.

In an exemplary embodiment of the invention, the level of the fracture-induced casing deformation risk level may be increased when the defect point of the local abnormal change in natural gamma and/or the defect point of the local abnormal change in well cementation homogeneity is located in a fracture-induced formation fracture zone.

In an exemplary embodiment of the invention, the risk factor of the casing comprises a sand blocking peak of a fracturing construction pressure curve, and when the number of the risk factors is multiple, the grade of the fracture-induced casing deformation risk level can be reduced by optimizing fracturing construction parameters.

In an exemplary embodiment of the invention, when the risk level is zero, the probability of casing deformation occurring may be predicted to be 0; when the risk degree is the first level, the probability of deformation of the casing is predicted to be less than or equal to 20 percent; when the risk degree is the second level, the probability of deformation of the sleeve is predicted to be between 20 and 50 percent; the risk level is third, the probability of casing deformation is predicted to be greater than 50%.

Advantageous effects and advantages of the present invention compared to the prior art may include at least one of the following:

(1) The method comprises the steps of respectively inputting logging data of a single well and rock mechanical parameters into an earth stress field model for simulation calculation, and repeatedly comparing and verifying a simulation result with microseism data in the process of really implementing fracturing, so that a fine earth stress field capable of relatively truly reproducing earth stress field distribution and fracture trend of a target block is obtained;

(2) According to the method, the block fine geostress field is used as input data for subsequent fracturing and casing deformation simulation, uncertainty of model input parameters caused by large logging data error or insufficient actual measurement parameters in the prior art is eliminated, the precision of the input geostress field is ensured, and the accuracy of predicting the casing deformation position by using a geological-fracturing engineering-cement sheath-casing integrated finite element model is improved;

(3) According to the method, various factors of casing deformation are organically linked, comprehensive integrated analysis is carried out, the casing deformation position induced by fracturing in a high geostress area can be predicted, the prediction result is consistent with more than 85% of fracturing casing deformation cases, and the accuracy is high;

(4) The method can find the deformation risk signs of the casing in time before and during the fracturing construction, and predict the deformation risk degree of the casing at the fracturing section;

(5) The method can qualitatively judge the risk degree of the deformation of the casing according to the number of risk factors.

Drawings

FIG. 1 illustrates a computational flow diagram of a method for integrated prediction of fracture induced deformation risk level of a hydrocarbon casing in an exemplary embodiment of the invention.

Fig. 2 shows a computational flow diagram for establishing a block-fine ground stress field in an exemplary embodiment of the invention.

Fig. 3 illustrates a structural schematic of a three-dimensional geological model of the weirs 202 patch in an exemplary embodiment of the invention.

FIG. 4A shows a well log data plot of a Wen 202 vertical well in an exemplary embodiment of the invention; FIG. 4B shows a rock mechanics parameter plot for a Wei 202 vertical well in an example embodiment of the invention.

FIG. 5 illustrates a plot of the results of a single well geological analysis of the Wen 202 vertical well in an exemplary embodiment of the invention.

FIG. 6 illustrates a maximum horizontal principal stress direction angle distribution plot over 13 individual wells in a Wedney zone in an exemplary embodiment of the invention.

FIG. 7A is a chart illustrating microseismic information for a well region of a Weir 202 in an exemplary embodiment of the invention; FIG. 7B shows a plot of microseismic information for a Welch 204 well zone in an exemplary embodiment of the invention; FIG. 7C illustrates a plot of fracture microseismic information for a Wei 202H10-3 horizontal well in an exemplary embodiment of the invention; FIG. 7D illustrates microseismic survey information for the Weir 204H1-5 in an exemplary embodiment of the invention.

FIG. 8 illustrates a ground stress field finite element model grid diagram for the Wei 202 block in an exemplary embodiment of the invention.

Fig. 9 shows a maximum horizontal principal compressive stress direction distribution plot in a wufeng-roman group formation for a weiqi 202 block in an example embodiment of the invention.

FIG. 10A shows a quincunx set of Wei 202 blocks-the minimum horizontal principal stress direction profile in a Longma stream formation in an exemplary embodiment of the invention; FIG. 10B shows the median principal stress direction profile in a Wufeng group-Longmaxi formation for a Wei 202 block; fig. 10C shows a three-dimensional vector direction distribution plot of the median principal stress in a wufeng group-romaji stream formation for the weiqi 202 block.

FIG. 11 illustrates a three-dimensional numerical solution cloud of the stress field of a Wei 202 vertical well reservoir unit in an exemplary embodiment of the invention.

FIG. 12 illustrates a casing loss curve and gamma log plot in an exemplary embodiment of the invention.

FIG. 13 illustrates a cementing quality tone and evaluation chart in an exemplary embodiment of the present invention.

Fig. 14 shows a construction pressure profile of a solar construction area in an exemplary embodiment of the invention.

Fig. 15 illustrates a well ant body diagram in an exemplary embodiment of the invention.

Fig. 16 shows a graph of the risk level of casing deformation in an exemplary embodiment of the invention.

Figure 17 shows a construction pressure profile for a remote area in an example embodiment of the invention.

Detailed Description

Hereinafter, the comprehensive prediction method of the fracture-induced deformation risk level of the oil and gas casing according to the invention will be described in detail with reference to the exemplary embodiments and the accompanying drawings.

In an exemplary embodiment of the invention, a method for comprehensive prediction of fracture-induced deformation risk level of a hydrocarbon casing is provided.

In the present embodiment, fig. 1 is a calculation flow chart of a comprehensive prediction method of fracture-induced deformation risk level of a hydrocarbon casing. As shown in FIG. 1, a comprehensive prediction method of the fracture-induced deformation risk level of a hydrocarbon casing may include the following steps:

s1, acquiring a single-well geological analysis result and a maximum horizontal principal stress direction angle based on logging data of a target block, and establishing a block fine geostress field.

Here, as shown in fig. 2, the analyzing the log data of the target block and establishing the block-based fine geostress field may include the following steps:

and S11, establishing a three-dimensional geological model of the target block by combining single-well horizon information on the basis of seismic wave data according to a well-seismic combination technical method (namely, combination of well logging and seismic).

Specifically, the overall geometric shape and the grid size of the target block can be constructed on the basis of three-dimensional seismic wave data by combining the structural fluctuation characteristics of the target block, then the horizon information of the target block can be demarcated by combining the single-well horizon information of the existing well of the target block, the geometric shape and the grid size of the stratum where the reservoir is located and other strata outside the reservoir are determined, and the three-dimensional geological model of the target block is obtained.

Here, the specific implementation of building the three-dimensional geological model of the target block may include: and establishing the grid geometric dimension of a geological model according to the three-dimensional seismic wave data, dividing the stratum and defining the size of grid units of each stratum, wherein the grid units of the stratum where the reservoir is located are smaller than those of other strata. The ratio of the grid cell thickness of the stratum where the reservoir is located to the grid cell thickness of the other strata may be 1:18 to 1:30. for example, the grid cell thickness of the other strata may be 20 times the grid cell thickness of the strata in which the reservoir is located.

The field application of the Wei 202 block of shale gas in Wenyuan region is taken as an example for explanation.

The ground and belly structure in the shale gas three-dimensional block in the West region is consistent in structure, simple in structure, high in northwest, low in southeast and near in east-west direction of the axis. The north part of the three-dimensional block mainly has Wei I high points, and the south part is a south wing of a Wei Yuan structure, so that faults are rare and fault fall is small. The structure of shale between limbs in the group of shaxi temple of the Jurassic system is known as follows: the three-dimensional block has simple structure and no fault development, the central north part is a Wei I high point of a Wei far structure, three secondary high points exist on the Wei I high point, and the axial direction is in the east-west direction; the south of the three-dimensional area is a Weiyuan south wing. The structure pattern of the abdomen is roughly consistent with the ground surface, but the local structure details have certain changes, folds are relatively enhanced, and faults are relatively developed. And because the fault throw is small, the influence on the initial ground stress field distribution is small. In addition, because the fault drop is small, the difficulty of identifying the fault through seismic wave data is large, and some faults with small drop are difficult to identify.

From the field data, the length of the Wei 202 block is 19km, and the width is 13.5km. According to the three-dimensional seismic wave data, establishing a three-dimensional geological model of the Wei 202 area, and combining a stratum sequence of a single-well region, dividing the geological model into 7 layers, wherein the layers are as follows from top to bottom: the ground level to the bottom boundary of the Jialing river group, the bottom boundary of the Jialing river group to the bottom boundary of the Feixuan group, the bottom boundary of the Feixuan group to the bottom boundary of the Tsiang river, the bottom boundary of the Tsiang river to the bottom boundary of the Tsiang river group, the bottom boundary of the Tsiang river to the bottom boundary of the Wufeng group (including the Longmaxi group stratum), the bottom boundary of the Wufeng group to the bottom boundary of the Hanwujia system, and the bottom boundary of the Hanwujia system to the elevation-5500 m. Wherein the reservoir is located in a quintet-romajxi group formation.

Considering the optimization of the finite element calculation amount, a denser grid is divided in a quincunx-ramus stratum (namely, a stratum where a reservoir is located) compared with grids of other strata. Namely, the grid of the five-peak group-Longxi group stratum is 20 layers, the minimum unit thickness is 1 meter, and other strata adopt larger unit size. The geological model for the Wen 202 block uses a total of cells 121068. Due to the influence of the formation degradation phenomenon, no distinction is made between the quintet group and the romanxi group, and the two groups are regarded as a formation together.

Fig. 3 shows a three-dimensional geological model diagram (depth units, meters) of the weiqi 202 block, showing the geometry and grid of the reservoir in a northwest high-southeast low configuration. In the figure, grids with different depths from top to bottom respectively represent the ground to the Jialin river group bottom boundary, the Jialin river group bottom boundary to the Feixian group bottom boundary, the Feixian group bottom boundary to the TJ bottom boundary, the TJ bottom boundary to the TJ bottom boundary (including the Longmaxi group stratum), the TJ bottom boundary to the TJ bottom boundary, and the TJ bottom boundary to the elevation-5500 m.

And S12, calculating rock mechanical parameters according to the logging data of the single well in the target block, and performing single-well geomechanical analysis on other logging data and rock mechanical parameters to obtain a single-well geological analysis result.

The other well log data may include gamma rays, compressional sonic time duration, and density of the formation. The rock mechanics parameters include young's modulus, poisson's ratio, cohesion (cohesion), and internal friction angle. And calculating rock mechanical parameters such as Young modulus and the like according to the acoustic logging data by adopting an empirical formula and a related calculation principle. For example, the rock mechanical parameters such as young's modulus can be calculated using the following correlation equations (equation (1) to equation (4)).

E＝10 ³ ρ _b ·[3(V _s /V _p ) ² -4]/Vs ² [(V _s /V _p ) ² -1]Formula (1)

v＝0.5[(V _s /V _p ) ² -2]/[(V _s /V _p ) ² -1]Formula (2)

C＝4.69433×10 ⁷ V _p ⁴ ρ _b [(1+v)/(1-v)](1-2v)(1+0.78V _sh ) Formula (3)

Wherein E is Young's modulus, MPa; ρ is a unit of a gradient _b Is rock density, g/cm ³ (ii) a Vs is longitudinal wave, us/m; vp is transverse wave us/m; v is Poisson's ratio, dimensionless; c is cohesive force, MPa; v _sh Is the mud content,%;

is the internal friction angle, degree.

The single well geological analysis results may include geostress results obtained by indirect analysis using other well log data and geostress results obtained by direct calculation using rock mechanics parameters. The geostress results obtained from indirect analysis using other logging data may include maximum horizontal principal stress obtained from indirect analysis using other logging data, minimum horizontal principal stress obtained from indirect analysis using other logging data, vertical principal stress obtained from indirect analysis using other logging data, and formation pore pressure obtained from indirect analysis using other logging data. The geostress analysis result obtained by directly calculating the rock mechanical parameters comprises maximum horizontal principal stress obtained by directly calculating the rock mechanical parameters, minimum horizontal principal stress obtained by directly calculating the rock mechanical parameters, vertical principal stress obtained by directly calculating the rock mechanical parameters and formation pore pressure obtained by directly calculating the rock mechanical parameters.

The field application of the Wei 202 block of shale gas in the Wenqian area is still taken as an example for illustration.

Fig. 4A, 4B, and 5 are single-well geomechanical analysis results obtained after performing single-well geomechanical analysis on the weizi 202 zone by using the method of step S12. Fig. 4A and 4B show logging data of a certain vertical well in the area 202 and rock mechanical parameters calculated according to the acoustic logging data, respectively. The lower well path of this well has a maximum dip angle of 8.6 degrees. The left column of FIG. 4A is the gamma ray (in: API) of the formation, the left two columns is the compressional sonic time duration DC (in: microseconds/feet), the left three columns is the borehole diameter (in: inches), the right one column is the density (in: g/cc), and the right two columns is the sonic time duration (in: milliseconds/feet). The left column of FIG. 4B is a plot of the modulus of elasticity (in Mpsi) for the lower well section of Wei 202, the left two columns are plots of the Poisson ratio, the right one is the bond strength (in MPa) of the formation material, and the right two columns are the internal friction angles (in degrees), where bond strength and internal friction angles are the primary parameters used to calculate collapse pressure from Mohr-Coulomb conditions.

FIG. 5 is a single well geological analysis of the West 202 vertical well, wherein the left column of FIG. 5 is a display of the principal components of geostress in the form of engineering gradients for the West 202 vertical well analysis, and the right column of FIG. 5 is a full-scale display of the results of the single well geostress analysis. In the figure, the graph corresponding to the curve a is a line segment ShG Elastic (w 202), the graph corresponding to the curve B is a line segment ShG-OBG (w 202), the graph corresponding to the curve c is a line segment SFG Mohr-Coulomb (w 202), the graph corresponding to the curve D is a line segment PP dt E3 (w 202), the graph corresponding to the curve E is a line segment OBG rhob (w 202), the graph corresponding to the point a is a square shin (w 202), the graph corresponding to the point B is a square block SHmax (w 202), the graph corresponding to the point D is a square block PP (w 202), and the graph corresponding to the point E is a square block OBG-m (w 202).

The icons of the curves in fig. 5 represent the following meanings: curve OBG rhob (i.e., curve E) represents the calculated (i.e., directly calculated using the rock mechanics parameters) vertical stress (i.e., overburden pressure), and square OBG-m (i.e., point E) represents the measured and analyzed (i.e., indirectly analyzed using other well log data) vertical stress; the curve ShG Elastic (i.e. curve a) represents the calculated (i.e. directly calculated using the rock mechanics parameters) minimum level principal stress, and the block ShGmin (i.e. point a) represents the minimum level principal stress measured by the hydraulic fracturing method (i.e. indirectly analyzed using other logging data); the curve SHG-OBG (i.e. curve B) represents the calculated maximum horizontal principal stress (i.e. directly calculated using the rock mechanics parameters), and the block SHmax (i.e. point B) represents the maximum horizontal principal stress obtained by measurement analysis (i.e. indirectly analyzed using other well log data); the curve PP dt e3 (i.e., curve D) represents the calculated (i.e., directly calculated using the rock mechanics parameters) formation pore pressure, and the block PP (i.e., point D) represents the formation pore pressure measured and analyzed (i.e., indirectly analyzed using other well log data). The curve SFG Mohr-Coulomb (i.e. curve c) represents the collapse pressure calculated from the molar Coulomb plastic yield condition (i.e. directly calculated using the rock mechanics parameters), i.e. the lower limit of the mud density window.

It can be seen that the value of the square OBG-m (i.e. the vertical stress obtained by indirect analysis of other logging data) is significantly smaller than that of the curve OBG (i.e. the vertical stress obtained by direct calculation of the rock mechanics parameters), with a relative error of about 10%. The value of the curve SHG at a depth of about 2560 m vertical (i.e. the maximum horizontal principal stress obtained by direct calculation using the rock mechanics parameters) coincides with the value of the block SHG-max (i.e. the maximum horizontal principal stress obtained by indirect analysis using other well log data), indicating that the SHG curve results are reasonable. The ShG curve is reasonable when the value of the ShG curve at a depth of about 2560 m vertical (i.e., the minimum level principal stress obtained by direct calculation using the rock mechanics parameters) coincides with the value of the ShGmin block (i.e., the minimum level principal stress obtained by indirect analysis using other well log data). The value of the curve PP at a depth of about 2560 m from the vertical (i.e., the formation pore pressure obtained by direct calculation using the rock mechanics parameters) coincides with the value of the square PP (i.e., the formation pore pressure obtained by indirect analysis using other logging data), indicating that the PP curve results are reasonable.

From the single well geomechanical results of fig. 5, it can be considered that: the magnitude of the vertical stress in the formation near the Wen 202 vertical well is centered among the three principal stress components and thus belongs to the "walk-slip fault stress Format".

And S13, comprehensively analyzing information of a World Stress Map (WSM), single well measurement information of existing wells and horizontal well fracturing microseism monitoring information in the target block, and obtaining the maximum horizontal principal Stress direction angle in the target block.

Here, the specific implementation of the integrated analysis of the information of the world stress map, the single well measurement information of the existing well, and the horizontal well fracture microseism monitoring information in the target block refers to: firstly, judging the maximum horizontal principal stress direction angle of the area to which the target block belongs by utilizing a world stress map, and determining the interval range to which the maximum horizontal principal stress direction angle in the target block belongs; then, according to the information measured by the single well, the interval range of the maximum horizontal principal stress direction angles of different structural parts in the target block is judged, and the change rule of the maximum horizontal principal stress direction angles in the target block along with the terrain is determined; and finally, analyzing the microseism monitoring information, and verifying and correcting the value of the maximum horizontal principal stress direction angle in the target block summarized by the two kinds of information by combining the analysis result of the microseism monitoring information, or supplementing the value of the maximum horizontal principal stress direction angle in the target block of some areas missed by the two kinds of information.

In this embodiment, the analyzing the microseismic monitoring information may include: judging the position of a horizontal well in a target block, which appears in a single-color strip-shaped distribution, in a microseism event point to be a seam network strip generated by the same fracturing segment, and judging the direction angle of the seam network strip to be the direction angle of the maximum horizontal principal stress of the position; determining the position of a color strip which consists of a plurality of colors and is distributed beyond the range of a reservoir layer in the micro-seismic event points of the horizontal well in the target block as the position of a natural fracture; and judging the condition that micro-seismic response points appear in the micro-seismic event points of the horizontal well in the target block and are distributed in a sheet or a ball shape as that the maximum horizontal principal stress directionality of the position is not obvious, and the direction of the minimum horizontal principal stress is close to the direction of the vertical principal stress.

Information display in the world stress map WSM: the regional geostress format of the Sichuan basin is characterized by mainly taking stress modes of a thrust fault and a slip fault. The direction of the maximum horizontal principal stress in the region is mainly east-west, and other directions such as northeast-southwest and northwest-southeast are also present.

Fig. 6 shows the distribution of the maximum principal stress directions of the reservoir quincunx group-the roman group on the single well site of 13 wells in the wegener region. The information integrates the stress azimuth analysis results of microseism monitoring, cross dipole array acoustic logging analysis and the like. The first dashed left line a in fig. 6 refers to a location at an altitude of-1400 m, the second dashed line B refers to a location at an altitude of-2400 m, and the third dashed line C refers to a location at an altitude of-3100 m. As shown in fig. 6, the information of the single well measurement shows: the maximum horizontal main stress shows a regular variation trend at different structural parts in the block. The whole weiyuan shale gas block can be divided into: a top flat zone between the upper left boundary to the dotted line a, a middle steep sloped zone between the dotted line a and the dotted line B, a lower right flat sloped zone between the dotted line B and the dotted line C, and a near dimpled flat zone between the dotted line C and the lower right boundary. The maximum horizontal principal stress direction angle of the top gentle band is 130 degrees, the maximum horizontal principal stress direction angle of the middle steep inclined band is 95-105 degrees (variation range is 10 degrees), the maximum horizontal principal stress direction angle of the right lower gentle inclined band is 85-95 degrees (variation range is 10 degrees), and the maximum horizontal principal stress direction angle of the near depression gentle band is 65-95 degrees (variation range is 30 degrees). From the above information it can be seen that: the maximum horizontal stress change in the quincunx-roman group of the reservoir in the veremote zone is complex, and not only changes along with the horizontal position (from 130 degrees to 65 degrees to 90 degrees), but also changes along with the depth in the reservoir by 30 degrees.

Fig. 7A, 7B, 7C and 7D are microseismic monitoring information of existing horizontal wells in the wegener block section. FIG. 7A is the microseismic information for the Welch 202 well, FIG. 7B is the microseismic information for the Welch 204 well, FIG. 7C is the fracture microseismic information for the Welch 202H10-3 horizontal well, and FIG. 7D is the microseismic monitoring information for the Welch 204H 1-5.

Since the location of the microseismic event point depends on both the direction of the maximum principal stress and the natural fracture distribution, the different colors in fig. 7A, 7B, 7C and 7D represent microseismic events generated at different times/fracture stages. When each color is distributed in a single color strip shape, the color is the slotted net strip generated by the same fracturing segment, and the direction angle of the slotted net strip is the direction angle of the maximum horizontal principal stress at the position. The solid line segments in fig. 7A, 7B, 7C and 7D are drawn according to this principle, which represents the direction of the maximum horizontal principal stress here. When the colored band representing the microseismic event is composed of multiple colors and the event points are distributed beyond the reservoir, this colored band represents the location of the natural fracture, represented by the dashed line segment in fig. 7A, 7B, 7C and 7D.

That is, in fig. 7A, 7B, 7C, and 7D, the solid line segments represent the direction of the maximum horizontal principal stress at the seam web strip produced by the same fracture section, and the dashed line segments represent the location of the natural fracture. In labeling the natural fracture locations denoted by the dashed line segments in FIG. 7A, reference is made to the microseismic event distributions in FIGS. 7C and 7D. It can be seen from FIG. 7D that the microseismic event point is beyond the target interval box and is a natural fracture related event. The azimuth of a natural fracture depends on the direction of movement of the geological formation, often does not coincide with the existing principal stress azimuth of the formation, and generally has no clear analytical relationship.

In addition, in fig. 7A, 7B, 7C, and 7D, the microseismic response points are clustered, indicating that the maximum horizontal principal stress is not significant in directionality, and the two principal stresses (the minimum horizontal principal stress and the vertical principal stress) are close in direction. As shown in the figure, the horizontal well fracturing micro-seismic monitoring information in the target block is displayed: the direction of the maximum main stress in the middle part of the block mainly runs along the east-west direction; the directions of the maximum main stress at the positions of two sides in the block deviate upwards from the respective two sides; on the left side of the sector 202, the azimuth angle may be up to 110 °.

The microseismic event points in the dashed circle in fig. 7A are distributed in a sheet-like fashion, indicating that the two horizontal principal stresses therein are of similar magnitude and have no clearly predominant principal stress direction. This is consistent with the single well maximum horizontal principal stress direction angle information in FIG. 6, where the principal stress direction angle of FIG. 6 varies over a wide range, the microseismic events are distributed in the form of sheets/clusters, with no apparent horizontal principal direction.

And S14, introducing a three-dimensional geological model, establishing a ground stress field finite element model of the target block, verifying a simulation result of the ground stress field of the target block based on a single well geological analysis result and a microseism actual measurement result of the existing well during fracturing construction, and solving the verified and qualified ground stress field value to construct a block fine ground stress field.

Specifically, the triaxial geostress principal component obtained from the single-well geological analysis result in step S12 and the maximum horizontal principal stress direction angle obtained from the analysis in step S13 are input as model setting parameters to the three-dimensional geological model of the target block obtained in step S11, and a geostress field finite element model of the target block can be established; and then carrying out the numerical simulation of the geostress field of the target block, comparing and verifying the numerical simulation result of the geostress field with the actual measurement result of the micro earthquake of the existing well during the fracturing construction period and the geological analysis result of the single well, adjusting the setting parameters of the model, taking the finite element model of the geostress field after the verification is qualified as the numerical model capable of truly simulating the geostress field of the target block, and obtaining the three-dimensional fine geostress field numerical solution of the target block which can be used as the input data of the follow-up fracturing and casing deformation simulation.

For example, the specific implementation of establishing the finite element model of the ground stress field of the target block may include: the units adopted by the geological model grid are three-dimensional 8-node linear units. The stratum where the reservoir is located is set as a C3D8 RP-pore pressure coupling unit, and other strata are set as C3D8R displacement units. Wherein C3D8RP and C3D8R refer to the cell type in the software Abaqus, C represents a solid cell, 3D represents three dimensions, 8 is the number of nodes this cell has, R refers to this cell being a reduced integral cell, and P refers to the three-line pore pressure. The model load was set as the gravity load. Boundary conditions of four sides and the bottom of the model are set as normal displacement constraints, and boundary conditions of the top are set as free boundaries. The initial conditions input initial stress parameters and initial pore pressure parameters, wherein the initial stress parameters include a principal component of triaxial stress (i.e., maximum horizontal principal stress, minimum horizontal principal stress, and vertical principal stress) and a maximum horizontal principal stress orientation angle.

And respectively inputting the geostress result obtained by indirectly analyzing other logging data and the geostress result obtained by directly calculating rock mechanical parameters as initial geostress parameters for each single well of the target block, and carrying out numerical simulation on the geostress field of the target block to obtain a corresponding geostress field numerical solution. And then comparing the two kinds of numerical solutions of the geostress field with the errors of the actual measured values of the geostress field of the existing well fracturing construction, constructing the numerical solution with smaller error with the actual measured values of the geostress field into a block fine geostress field, and using the block fine geostress field as input data of subsequent fracturing and casing deformation simulation.

For example, whether the maximum horizontal principal stress direction distribution of the reservoir obtained by the two simulations accords with the micro-seismic actual measurement result of the existing well during the fracturing construction period, whether the stress format of the reservoir accords with the single-well geomechanical analysis result, whether the geostress field distribution rule of the reservoir accords with the micro-seismic actual measurement result of the existing well during the fracturing construction period, and the like can be contrastively analyzed, the geostress analysis result with smaller error in the two simulations is judged to be more suitable to be set as the simulation parameter of the block geostress field for reproducing the actual fracturing construction process, and the obtained geostress field numerical solution is more suitable to be used as the input data of the subsequent fracturing and casing deformation simulation. Considering that the main purpose of the model numerical result is to perform subsequent casing deformation prediction caused by fracturing, the model parameter preparation mainly emphasizes that the minimum principal stress result of the numerical solution is close to the measured value, namely, the rationality of the model is ensured by using the principle of preferentially ensuring that the minimum principal stress result of the numerical solution is closest to the measured value and considering that the numerical solution of the direction angle of the maximum horizontal principal stress is consistent with the middle value trend of the measured value.

The aim of the single-well geomechanical analysis is to analyze the extension direction of the fracture, and the orientation of the extension of the fracture can be predicted by determining the orientation of the ground stress as the fracture always extends along the direction of the vertical minimum horizontal principal stress. The details of the geological local structure of different well sections are changed to a certain extent, so that the results of the ground stress analysis suitable for simulating the vertical well are different. By taking the crustal stress result obtained by indirectly analyzing other logging data and the crustal stress result obtained by directly calculating rock mechanical parameters as initial crustal stress parameters, numerical simulation of the crustal stress field of a target block is respectively carried out, the simulation accuracy of two groups of crustal stress data can be judged, and therefore crustal stress field simulation initial input parameters which are most suitable for simulating the vertical well are selected. Therefore, for all vertical wells for searching the target block, the ground stress analysis result of the simulation parameters of the block ground stress field which is most suitable for being set to reproduce the actual fracturing construction process (namely the error is minimum) is repeatedly searched, the overall simulation precision of the ground stress field model can be improved, the fine ground stress field is established, and the simulated fracture extension trend is close to the real fracture state during subsequent fracturing and casing deformation simulation.

The maximum horizontal principal stress azimuth of the single-well geological analysis result in step S12 and that in step S13 are input as initial conditions to the ground stress field model of this step.

Table 1 is a list of values of model elastomechanics parameters after integrating the above single well geological analysis results and experience. Wherein the modulus of elasticity varies with depth. The computation model adopts abaqus user subprogram to realize the TVD depth (TVD refers to vertical depth) dependence characteristic.

TABLE 1 tabulation of values of model elastomechanics parameters after synthesis of single well analysis results and experience

According to the method, stratum material parameters (namely rock mechanical parameters) such as Young modulus and initial ground stress related parameters are calculated according to logging data of a single well, uncertainty of model input parameters caused by insufficient measured parameters can be reduced, and accuracy of initial input parameters of a fine ground stress field model is guaranteed.

In addition, the collapse pressure (for example, curve c in fig. 5) calculated according to the molar coulomb plastic yield condition in step S12 may be compared with the simulation result of the ground stress field model in this step, and is not necessarily input into the ground stress field model.

Fig. 8 shows the finite element model mesh of the ground stress field of the wein 202 block from the geological model mesh established in step S11. The adopted units are three-dimensional 8-node linear units, C3D8RP displacement-pore pressure coupling units are arranged in the reservoir, and C3D8R displacement units are arranged outside the reservoir. The long side direction is taken as the x-axis direction. The load of the model is the gravity load. Boundary conditions are normal displacement constraint of four sides and normal displacement constraint of the bottom; the top is the ground, free boundary.

Setting initial conditions by using the three-dimensional finite element mesh model in fig. 8, and establishing a ground stress field finite element model of the target block. The initial conditions included an initial stress field and an initial pore pressure field, where the pore pressure field was only present in the quintet-romaji formation of the target layer, and the pore pressure coefficient of the wei 202 block was 1.4g/cc. Setting of initial earth stress field earth stress component parameter setting of each formation is carried out according to the single well earth stress component given in figure 5.

The distribution of the direction of the maximum horizontal principal compressive stress in the five peak group-romanxi group strata of the wei 202 block obtained by numerical calculation is shown in fig. 9. As seen in fig. 9, the maximum horizontal principal stress in the numerical result is about 130 ° in the principal stress direction of the gentle band at the upper left of the weirs 202 block; the direction of maximum horizontal principal stress at the lower right portion of the block gradually transitions to approximately 90 of the east-west direction. This result corresponds to the analysis of the directional angle measurements given in fig. 6.

Fig. 10A and 10B show the directions of the minimum horizontal principal compressive stress and the intermediate principal stress in the wufeng group-roman group formation of the weiwei 202 zone, respectively, and fig. 10C is a three-dimensional vector direction distribution diagram of the intermediate principal stress. As can be seen from fig. 10A, 10B and 10C, the central principal stress is in a near vertical direction at the bottom right/south east position of the wei 202 block. This indicates that the vertical stress at these locations is the central principal stress component, and the stress pattern belongs to the "slip fault stress pattern". This result is consistent with the single well geomechanical results of figure 5.

Fig. 11 is a three-dimensional numerical solution cloud chart (TVD =2550 m) of the stress field of a unit of a reservoir in a well with a well of wei 202 vertical wells. The unit has a side length of 275 metres. The sign convention in the figures follows that of solid mechanics, i.e. tensile stress is positive and compressive stress is negative. As seen from the figure, the magnitude of the stress gradually increases from northwest to southeast. Meanwhile, table 2 shows the comparison of the numerical solutions and measurements of the stresses in the vertical well of wei 202. As can be seen from table 2, the amplitudes of the two horizontal principal stresses in the numerical result are very close to the measured values, and the error between the vertical stress and the measured values is relatively large, and is 6.37%.

TABLE 2 comparison of the numerical solutions and measurements of the well-ground stress of Wei 202 vertical well

The simulation results are analyzed, and the numerical solution of the magnitude and direction of the main stress is found to have a certain error with the measured value. One reason for this is that the simplified model used for the calculations may deviate from the actual situation in terms of local construction details. In addition, the measured values give a range of principal direction angles, while the principal stress values are values in the average sense. This means that the measured value itself is also an average value, with a margin of error.

Considering that the main purpose of the model numerical result is to predict casing deformation caused by fracturing later, the model parameter preparation mainly emphasizes that the minimum principal stress result of the numerical solution is close to the measured value, namely, the rationality of the model is ensured by using the principle of ensuring that the minimum principal stress result of the numerical solution is closest to the measured value and considering that the numerical solution of the direction angle of the maximum horizontal principal stress is consistent with the middle value trend of the measured value.

Therefore, after comprehensive analysis and consideration, the results of the geostress field numerical values can be constructed into a fine geostress field of the Wei 202 block, so as to be used as input data for subsequent fracturing and casing deformation simulation.

And S2, establishing a geological-fracturing engineering-cement sheath-casing integrated finite element model based on the block fine geostress field, and performing three-dimensional finite element deformation and stress analysis on the casing string in the full horizontal section of the horizontal well to obtain the initial stress distribution of the casing string before fracturing.

Specifically, the method comprises the following steps: and (2) establishing geometric models of a well, a cement sheath and a casing on the basis of the finite element model of the ground stress field of the block in the step (S1), setting model data of fracturing construction, obtaining a finite element model integrating geology-fracturing engineering-the cement sheath-the casing, and taking the numerical simulation result of the ground stress field of the block as input data of fracturing and casing deformation simulation.

For example, creating a geologic-fracturing project-cement sheath-casing integrated finite element model may include the following: the method comprises the steps of firstly establishing a geometric model of a well, then setting model data, wherein the model data comprises reservoir thickness distribution, horizontal section logging data, ground stress field distribution, designed fracturing construction parameters, perforation parameters, formation pressure coefficients, ground stress parameters and rock mechanics parameters, and finally considering multiple materials (including formation materials, cement ring materials and casing materials), multiple geometric shapes (including formation geometric shapes, cement ring geometric shapes and casing geometric shapes), two physical fields of structural deformation and physical seepage, fluid pressure loads, ground stress loads, gravity loads, elastic mechanics models and plastic mechanics models to establish a three-dimensional finite element model of the well. For a geological-fracturing engineering-cement sheath-casing integrated mathematical model for predicting casing deformation, a basic theoretical model is a plastic loading yield criterion of metal, including a Teriscascal (Tresca) yield criterion of formula (5) and a Miss (von Mises) yield criterion of formula (6). Both are yield criteria based on shear strength. In other words, the plastic deformation of the metal material is a shear plastic deformation.

τ _max = K type (5)

(σ ₁ -σ ₂ ) ² +(σ ₂ -σ ₃ ) ² +(σ ₃ -σ ₁ ) ² ＝2σ _s ² ＝6K ² Formula (6)

Wherein σ ₁ ，σ ₂ ，σ ₃ Three principal stresses, MPa, σ _s The yield stress, MPa, K is the shear yield strength, MPa, of the material.

The tensile plasticity of the sleeve appears macroscopically as tensile plastic deformation, but the micro mechanism is shear plastic slippage of the metal crystals. Based on this, considering the environment in which the casing is located, consider: in fracturing operations, there is a significant risk of casing deformation at points along the horizontal section axis where shear loads are greatest around the casing if there are points of failure (e.g., points of failure in gamma, points of poor well cementation). These places are the areas where the shear load is the greatest that should be avoided.

The finally established model of 'geology-fracturing engineering-cement sheath-casing integration' comprises the following components:

1) Multiple materials, multiple geometries;

2) Two physical fields of structural deformation and seepage;

3) Fluid pressure loads, ground stress loads, gravity loads;

4) Elastic mechanical constitutive model and plastic mechanical constitutive model.

The mechanical behavior of this complex model can be summarized by the following equation:

K(u)·u＝F

the variables are defined here as:

k is a system stiffness matrix, and represents the material properties of the model, including elastic and plastic constitutive properties and geometric characteristics; u is a motion vector including the displacement of each point in the model and the pore pressure; f is a load vector representing the various loads involved in the model.

And S3, carrying out three-dimensional finite element deformation and stress analysis on the casing string subjected to reservoir fracturing, calculating the change of a ground stress field caused by fracturing, and finding out the position distribution of applying a shearing load to the casing string.

Specifically, model parameters can be set for a target interval of a casing string in the geological-fracturing engineering-cement sheath-casing integrated finite element model according to designed fracturing construction parameters, numerical simulation of reservoir fracturing is carried out, earth stress field change caused after fracturing construction of the target interval is calculated, and position distribution of applying shear load to the casing is found.

And S4, carrying out geological-well cementation-casing combined integrated casing deformation analysis on the horizontal well, wherein the analysis comprises gamma curve distribution analysis of a horizontal section of the well track, well cementation quality and sound amplitude curve distribution analysis of the horizontal section of the well track, fracturing construction pressure curve analysis of the horizontal section of the well track, microseismic monitoring result analysis of the horizontal well, and simulation calculation of external shearing force change analysis of the shaft of the horizontal section of the well track.

And S5, predicting the position of the casing deformation induced by the fracturing according to the casing deformation analysis result, wherein the casing deformation position comprises the position of a local abnormal bulge of a gamma curve, the position of abnormal well cementation homogeneity, the maximum shear load point caused by a fracturing section where a construction pressure peak value is located, and the outer edge of a stratum fracture area caused by fracturing.

On the basis of a great deal of research, three major influencing factors of fracturing to induce casing deformation are confirmed, namely geological factors, well cementation factors and construction engineering factors.

The geological factors mean that the stratum has asymmetric rigidity and obvious local change, and the casing in the area is subjected to larger external shear force than other positions, so that the casing deformation probability is high. Before fracturing construction, positions with asymmetric stratum rigidity and obvious local change in a horizontal section of a well track can be identified by analyzing a gamma logging curve. For example, when a gamma log curve at the horizontal section of the well track has local abnormal bulges, the information of the characteristic identifier can be considered as the formation rigidity asymmetry and local change abnormality. The local abnormal bulge of the gamma curve can be judged according to the fact that the local gamma value is larger than 200GAPI.

In addition, the outer edge of a stratum fracture area generated by fracturing has the conditions that the stratum rigidity is asymmetric and the local rigidity is obviously changed, and the probability of deformation of the sleeve at the position is high. But this location can only be discovered if the corresponding log data is obtained after the construction (during or after the fracturing construction). Therefore, in order to predict the outer edge of a stratum fracture area generated by fracturing in advance and identify the position where the stratum of the horizontal section of the well track is easy to have asymmetric rigidity and obvious change of local rigidity after fracturing construction, the method can analyze the corresponding casing deformation at the position through numerical simulation of reservoir fracturing at the fracturing construction design stage. Fracture-induced shear-localized zones, which may be considered fracture-induced fracture zones of the formation, may be obtained in the results of numerical simulations of reservoir fracturing. Here, the shear localized zone refers to a region where shear strain is concentrated under the combined action of formation injection pore pressure and an earth stress field, and a casing in the region is subjected to a formation load which is significantly higher than that of other positions, so that the casing in the region is more likely to deform than that of other positions. In order to verify the accuracy and precision value of the shearing localization zone obtained by simulation, the position of the outer edge of a stratum fracture zone generated by fracturing can be analyzed and determined by combining with the microseismic monitoring result of the horizontal well.

For another example, a natural fracture region which may exist may be judged by ant body data, well leakage data and the like in geology before fracturing, and a stratum fracture region which may appear may be judged in advance by the fracture region.

The well cementation factor refers to abnormal well cementation homogeneity, namely that the well cementation quality has large local change and local quality defect points, the well cementation cement in the area is not cemented or partially cemented, and the anti-shearing capability is poor, so that the probability of casing deformation is high. Before fracturing construction, the position of poor cementing quality of a horizontal section of a well track can be identified by analyzing the cementing quality and the sound amplitude curve. For example, when the well cementation quality and the sound amplitude curve of the horizontal section of the well track have local obvious changes of the well cementation sound amplitude, the information of the characteristic identification can be considered as abnormal well cementation homogeneity. The judgment basis of the abnormal well cementation homogeneity can be that the local acoustic amplitude value is higher than an interface with poor cement cementation, and the local evaluation result of the well cementation quality is poor.

The construction engineering factor means that the pressure of the fracturing construction is too large and exceeds the allowable range, and the local external shearing force borne by the casing in the area is obviously higher than that of other positions, so that the probability of casing deformation is high. In the fracturing construction process, the position of the horizontal section of the well track with overlarge construction pressure can be identified by analyzing a fracturing construction pressure curve. For example, when there is a significant local spike in the construction pressure curve, perhaps due to a pressure surge caused by sand plugging, the signature information may be considered as fracturing construction pressure exceeding the allowable range. Here, the peak value of the construction pressure curve means that the pressure is suddenly increased or decreased so that the pressure curve is remarkably fluctuated. The judgment basis of the maximum shearing load point caused by the fracturing section where the peak value of the construction pressure curve is located is that the pressure surge or the shock reduction amplitude is larger than 10MPa/min, and the pressure change curve is not a straight line.

That is, prior to fracture construction, the location of fracture-induced casing deformation may be predicted by:

(1) And analyzing the gamma logging curve of the well track horizontal section of the target well, finding out the position of the well track horizontal section casing string corresponding to the gamma logging curve with the local gamma value larger than 200GAPI, and predicting the position as the position of the fracture-induced casing string deformation.

(2) And analyzing the well cementation quality and the sound amplitude curve of the horizontal section of the well track of the target well, finding out the position of the casing string of the horizontal section of the well track, which has the local sound amplitude higher than the interface with poor cement cementation and corresponds to the local evaluation result of the well cementation quality as the difference, and predicting the position as the position of the deformation of the casing string induced by the fracturing.

(3) The method comprises the steps of utilizing parameters of a fracturing construction design stage to conduct numerical simulation of reservoir fracturing on a target well, calculating the change of a ground stress field caused by fracturing, predicting a shearing localization zone caused by fracturing, and predicting the position of a well track horizontal section casing string corresponding to the shearing localization zone as the position of casing deformation induced by fracturing.

During and after fracturing construction, the Maximum Shear Loading Points (MSLPs) caused by the fracturing section where the construction pressure peak value is located can be found out by analyzing the fracturing construction pressure curve of the well track horizontal section of the target well, and the MSLPs are predicted as the positions where the fracturing induces casing deformation.

For the target well, the positions of the casing deformation possibly occurring can be analyzed and predicted in the four ways before and during fracturing, and the positions of the casing deformation obtained through prediction are calibrated on the casing, so that a prediction map of the positions of the casing deformation induced by fracturing is obtained.

For example, the field application of 204H12-5 well sections of three-dimensional blocks of shale gas in Weekdistance is taken as an example for illustration.

FIG. 12 is a graph of casing loss (i.e., casing deformation) for well 204H12-5 and a gamma ray log analysis. In fig. 12, curve a is the maximum inner diameter, curve b is the average inner diameter, and curve c is the minimum inner diameter. FIG. 13 is a chart of the cementing quality acoustic amplitude and evaluation of well 204H 12-5. Wherein, curve A of FIG. 13 is the pipe collar value, curve B is the well diameter value, and curve C is the natural gamma value.

Prior to the fracturing job, the gamma log of the target well 204H12-5 (as shown in FIG. 12) is analyzed to find: the gamma values at the underground depths of 3100m and 3200m are suddenly increased from 70API to 190API, which indicates that the two points belong to the positions of abnormal bulges of the gamma curve and possibly the positions of deformation of the casing. Meanwhile, the well cementation quality and the sound amplitude curve (shown in figure 13) of the target well 204H12-5 are analyzed to find that: in the depth position after the underground depth of 3200m, the sound amplitude changes locally and obviously, namely the sound amplitude has larger fluctuation, which shows that the outer interface cementing quality of the position has poor homogeneity and is possibly the position of casing deformation. Therefore, the comprehensive well logging data, the natural fracture distribution data, the fracturing construction parameters and other data analysis think that: the stratum rigidity at the position with the underground depth of 3200m is asymmetric, the well cementation quality is poor, the casing deformation is easy to occur, and the position where the casing deformation is induced by fracturing is predicted.

In actual production applications for target well 204H12-5, it was found that the casing string at the predicted location was deformed. As shown in fig. 12, in the region around the downhole depth 3200m, the minimum inner diameter (i.e. curve c), the average inner diameter (i.e. curve b) and the maximum inner diameter (i.e. curve a) of the casing are sharply reduced, i.e. 3200m downhole is the location where casing deformation occurs. In addition, in fig. 13, it can also be seen that the caliper curve (i.e., curve B) changes gently from a gentle up-and-down fluctuation at a depth position 3100m or less downhole, which indicates that casing deformation occurs 3100m or less downhole.

It is demonstrated that the positions of local abnormal bulges of the gamma curve and the positions of the well cementation homogeneity abnormity in the logging data can be predicted as the positions of fracture-induced casing deformation.

Also for example, the field application of a yang 105H3-2 well section in a solar construction area is described as an example.

FIG. 14 is a graph of the 7 th (2935-2855 m downhole) fracture construction of the Wenyang 105H 3-2. In FIG. 14, curve a is the well pressure at yang 105H3-2, curve b is the construction displacement, and curve c is the sand concentration.

During the fracturing construction of the 7 th section (2935-2855 m downhole) of the target well male 105H3-2, analyzing the fracturing construction curve (as shown in FIG. 14) can find that: during the whole construction period, a plurality of abnormal peak values appear in the construction pressure at the position above the dotted line, which shows that the construction pressure of the 7 th section is too large in the construction process and exceeds the allowable range, and the position of the deformation of the sleeve can be formed. Meanwhile, the 7 th section is located in the shearing localization zone range and possibly in the position of casing deformation by utilizing the simulation calculation of the fracturing construction parameter of the 7 th section for the fracturing of the water inlet reservoir and analyzing the simulation result. Therefore, the comprehensive well logging data, the natural fracture distribution data, the fracturing construction parameters and other data analysis think that: the position of the underground depth 2935-2855m is a stratum fracture area caused by fracturing, the construction pressure is too large and exceeds the allowable range, the casing deformation is easy to occur, and the position of the casing deformation induced by fracturing is predicted.

In practical production applications for target well 204H12-5, it was found that the target well encountered a blockage at well depth 2761m when pumping bridge plug at section 8, indicating that the casing at section 7 was deformed.

Therefore, the position of the abnormal sharp peak in the construction pressure curve and the position of the shearing localization zone in the numerical simulation of the reservoir fracturing can be predicted to be the position of the fracturing-induced casing deformation.

As another example, a 202H14-3 well section of a three-dimensional block of shale gas in a Weekremote area is taken as an example for illustration.

Before fracturing construction, the well ant body diagram of the well 202H14-3 can be analyzed to judge a possible natural fracture area, and a possible stratum fracture area is judged in advance through the fracture area. Fig. 15 is a diagram of a well ant body of the well 202H 14-3. As shown in fig. 15, it can be seen that at sections 21-23, locations 3068-3340m downhole (locations of dashed circles) there are natural fracture zones across the wellbore, and the casing at this location is in a formation fracture zone. Meanwhile, by utilizing the simulation calculation of the fracturing construction parameters of the well 202H14-3 for the fracturing of the water-intake reservoir, the 21 st to 23 th sections are found to be positioned in the shearing localized zone range through analysis of simulation results, and the situation that the position of 3068 to 3340m in the underground (namely the position of a dotted circle frame in the figure 15) is the position of a broken zone of a natural fracture zone, so that the deformation of the casing is easy to occur is verified.

In actual production applications of the target well 202H14-3, it was found that after the 10 th interval (i.e., well 4017-4084 m) of the well was completed, the pump bridge was blocked at 3290.81m, indicating that the casing was deformed at the location 3068-3340m downhole.

It is thus demonstrated that the location of the shear-localized zone in the numerical simulation of reservoir fracturing can be predicted as the location of fracture-induced casing deformation.

And S6, defining risk factors influencing casing deformation, and judging the risk level of the casing deformation induced by the fracturing according to the number of the risk factors existing in the casing.

The risk factors comprise a fracturing construction pressure curve sand plugging peak, natural gamma local abnormal change, well cementation homogeneity local abnormal change and the overlapping of a defect point of the natural gamma local abnormal change and a defect point of the well cementation homogeneity local abnormal change. As shown in fig. 16, for the same size of casing (for example, the pipe diameter is 127mm to 146.3 mm), when the thickness of the casing is less than 11mm, and the number of risk factors is 0, the risk level is zero, and the probability of casing deformation is 0; when the number of the risk factors is 1, the risk grade is the first grade (or called as medium grade), and the probability of casing deformation is less than or equal to 20%; when the number of the risk factors is 2, the risk level is the second level (or called as large), and the probability of casing deformation is 20-50%; the risk number is 3 or 4, the risk level is third (or called very large), the probability of casing deformation is over 50%, and the third level is higher than the second level and higher than the first level. For the sleeves with the same size (for example, the pipe diameter is 127 mm-146.3 mm), when the thickness of the sleeve is more than 11mm, and the number of risk factors is 0, the risk level is zero, and the probability of sleeve deformation is 0; when the number of the risk factors is 1, the risk level is the first level (or called as medium), and the probability of casing deformation is less than or equal to 20%; when the number of the risk factors is 2 or 3, the risk level is the second level (or called as large), and the probability of casing deformation is 20-50%; the risk number is 4, the risk level is third (or called very large), the probability of casing deformation is more than 50%, and the third level is higher than the second level and higher than the first level. Equivalently, when the fracture inducing casing deformation risk level is judged by the number of risk factors present in the casing, the greater the number of risk factors, the higher the fracture inducing casing deformation risk, at a predetermined casing size and thickness.

Here, it should be noted that, when the risk factors existing in the casing include the sand plugging peak of the fracture construction pressure curve, and the number of the risk factors is multiple, the level of the risk degree of the fracture-induced casing deformation can be reduced by optimizing the fracture construction parameters. For example, when the casing thickness of the target well is less than 11mm, if the casing of the target well has risk factors including a fracturing construction pressure curve sand plugging peak, a natural gamma local abnormal change and a well cementation homogeneity local abnormal change, the number of the risk factors is 3, and the risk level is very large (i.e. the third level); when fracturing construction is carried out, fracturing construction parameters are optimized to enable the casing to avoid the occurrence of fracturing construction pressure curve sand blocking peaks, risk factors existing in the casing of a target well comprise natural gamma local abnormal changes and well cementation homogeneity local abnormal changes, the number of the risk factors is 2, and the risk grade is large (namely the second grade). That is, the level of risk of fracture-induced casing deformation can be reduced by optimizing fracture construction parameters.

The degree of risk of fracture-induced casing deformation may increase when the points of failure of local abnormal changes in natural gamma and of well-cementation homogeneity are located in the fracture zone of the formation created by the fracture. The location of the fracture zone of the formation created by the fracture may be determined by pre-fracture geological data and/or numerical simulation of the reservoir fracture. For example, when the casing thickness of the target well is less than 11mm, if the risk factors existing in the casing of the target well include local abnormal changes of natural gamma, the number of the risk factors is 1, and the risk level is medium (i.e. the first level); however, when the natural gamma defect point is found to be right in the fracture-induced formation fracture zone (i.e. the shear-localized zone) through numerical simulation, the deformation probability of the casing becomes high, and it should be considered that the number of risk factors is 2 and the risk level is high (i.e. the second stage).

When the defect point of the local abnormal change of the natural gamma and the defect point of the local abnormal change of the well cementation homogeneity are positioned in a stratum fracture area caused by fracturing, a danger factor exists actually, the range of a local shear zone can be controlled and the local shear force can be reduced by reducing the construction pressure and the scale, and therefore the risk of casing deformation is favorably reduced.

In this embodiment, the optimized fracturing construction parameters may include controlling the concentration of the sand-carrying fluid, increasing the viscosity of the working fluid, increasing the volume of the step, and increasing the amount of the low sand concentration 100 mesh silt.

Taking 204H12-5 well section in a remote area as an example, the risk degree analysis of casing deformation (called deformation for short) is carried out.

A graphical analysis of the casing damage (i.e., casing deformation) of the well 204H12-5 is shown below for three factors. Fig. 12 is a graph of casing loss curve and gamma log curve, where curve a in fig. 12 is the maximum inner diameter, curve b is the average inner diameter, and curve c is the minimum inner diameter. FIG. 13 is a graph of the sound amplitude and evaluation of the well cementation quality, curve A of FIG. 13 being the casing collar value, curve B being the hole diameter value, and curve C being the natural gamma value. FIG. 17 is a graph of construction pressure, with the differently-labeled curves of FIG. 17 representing different sections of the construction well.

Before fracturing construction, well logging data of a well 204H12-5 is analyzed, and whether three risk factors of natural gamma local abnormal change, well cementation homogeneity local abnormal change and overlapping of a defect point of the natural gamma local abnormal change and a defect point of the well cementation homogeneity local abnormal change exist in a target well (the well 204H 12-5) or not is judged.

Analyzing the gamma log of the target well 204H12-5 (as shown in FIG. 12) finds that: the gamma values at the downhole depths of 3100m and 3200m suddenly increase from 70API to 190API, which indicates that the two points belong to the positions of abnormal bulges of the gamma curve. That is, the target well has a risk factor of local abnormal change in natural gamma.

Then, the well cementation quality and the sound amplitude curve (as shown in fig. 13) of the target well 204H12-5 are analyzed to find that: in the depth position after the underground depth of 3200m, the sound amplitude changes locally and obviously, namely the sound amplitude fluctuates greatly, which shows that the quality homogeneity of the outer interface cementing at the position is poor. That is, the target well presents a risk factor of local abnormal variation in the homogeneity of the well cementation.

Meanwhile, comparing fig. 12 and fig. 13, it is found that the position of the target well 204H12-5 where the poor cementing quality occurs and the position where the abnormal projection of the gamma curve occurs are both located at the depth position after the downhole depth of 3200 m. That is, the target well has a risk factor that a defective point of a local abnormal change in natural gamma overlaps with a defective point of a local abnormal change in well cementation homogeneity.

Finally, during the fracturing construction process, the construction pressure curve diagram (shown in FIG. 17) of the target well 204H12-5 is analyzed to find that: the construction pressure curve is perfect, and a sharp peak value of pressure which increases sharply does not appear. That is, the target well does not have the risk factor of a fracture construction pressure curve sand plugging peak.

In addition, the mechanical behavior of the casing string was analyzed, the stress distribution of the casing string at the initial installation stage was obtained, and it was confirmed that the casing string was safe under initial loading, and the stress was not a major contributor to casing deformation during later fracturing. That is, the location of the formation fracture zone created by the fracture does not increase the risk of casing deformation.

Therefore, by combining the above information, it can be considered that the target well 204H12-5 includes three risk factors of local abnormal change of natural gamma, local abnormal change of well cementation homogeneity, and overlapping of a defect point of the local abnormal change of natural gamma and a defect point of the local abnormal change of well cementation homogeneity, and the casing thickness of the target well 204H12-5 is less than 11mm, so the casing deformation risk degree grade of the target well 204H12-5 is predicted to be very large (i.e. the third grade), and the probability of casing deformation is predicted to be more than 50%.

In actual production applications for target well 204H12-5, it has been found that the casing string at the predicted location is deformed. As shown in fig. 12, in the region of the downhole depth of 3200m or so, the minimum inner diameter (i.e. curve c), the average inner diameter (i.e. curve b) and the maximum inner diameter (i.e. curve a) of the casing are sharply reduced, i.e. 3200m downhole is the location where casing deformation occurs. In addition, it can also be seen in fig. 13 that the caliper curve (i.e., curve B) changes from gentle to fluctuating at a depth position after 3100m downhole, which indicates casing deformation after 3100m downhole.

Therefore, the method for predicting the risk degree of fracturing-induced casing deformation in the step S6 can predict the risk degree and probability of fracturing-induced casing deformation in advance before and during fracturing construction.

In summary, the beneficial effects and advantages of the invention include at least one of the following:

(1) The method comprises the steps of respectively inputting logging data of a single well and rock mechanical parameters into a ground stress field model for simulation calculation, and repeatedly comparing and verifying a simulation result and microseism data when fracturing is really carried out, so that a fine ground stress field capable of truly reproducing ground stress field distribution and fracture trend of a target block is obtained.

(2) The method takes the block fine geostress field as the input data of the subsequent fracturing and casing deformation simulation, eliminates the uncertainty of model input parameters caused by large logging data error or insufficient actual measurement parameters in the prior art, ensures the precision of the input geostress field, and improves the accuracy of predicting the casing deformation position by using the geological-fracturing engineering-cement sheath-casing integrated finite element model.

(3) The method organically associates various factors of casing deformation, carries out comprehensive integrated analysis, can predict the casing deformation position induced by the fracturing in the high geostress area, and has high accuracy because the prediction result conforms to more than 85% of fracturing casing deformation cases.

(4) The method can find the casing deformation risk signs in time before and during the fracturing construction, and predict the risk degree of casing deformation at the fracturing section.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A comprehensive prediction method for the risk level of fracturing-induced oil and gas casing deformation is characterized by comprising the following steps:

acquiring a single-well geological analysis result and a maximum horizontal principal stress direction angle based on the logging data of a target block, and establishing a block fine geostress field;

establishing a geological-fracturing engineering-cement sheath-casing integrated finite element model based on the block fine geostress field, and performing three-dimensional finite element deformation and stress analysis on the casing string at the full horizontal section of the horizontal well to obtain the initial stress distribution of the casing string before fracturing;

carrying out three-dimensional finite element deformation and stress analysis on the casing string subjected to reservoir fracturing, calculating the change of a ground stress field caused by fracturing, and finding out the position distribution of applying a shear load to the casing string;

performing geological-well cementation-casing combined integrated casing deformation analysis on the horizontal well, wherein the analysis comprises the gamma curve distribution analysis of a horizontal section of a well track, the well cementation quality and sound amplitude curve distribution analysis of the horizontal section of the well track, the fracturing construction pressure curve analysis of the horizontal section of the well track, the microseism monitoring result analysis of the horizontal well and the simulation calculation of the change analysis of the shearing force outside the shaft of the horizontal section of the well track;

predicting the positions of the fracture-induced casing deformation according to the casing deformation analysis result, wherein the positions of the casing deformation comprise the positions of local abnormal bulges of a gamma curve, the positions of well cementation homogeneity abnormity, the maximum shear load point caused by a fracture section where a construction pressure peak value is positioned, and the outer edge of a stratum fracture area caused by fracturing;

judging the risk level of the deformation of the casing induced by the fracturing according to the number of risk factors existing in the casing, wherein the risk factors comprise a fracturing construction pressure curve sand blocking peak, natural gamma local abnormal change, well cementation homogeneity local abnormal change and the overlapping of a defect point of the natural gamma local abnormal change and a defect point of the well cementation homogeneity local abnormal change; for the casings with the same size, when the thickness of the casing is less than 11mm, the number of risk factors is 0, the risk level is none, when the number of risk factors is 1, the risk level is the first level, when the number of risk factors is 2, the risk level is the second level, when the number of risk factors is 3 or 4, the risk level is the third level, and the third level is higher than the first level; when the thickness of the sleeve is larger than 11mm, when the number of risk factors is 0, the risk level is none, when the number of risk factors is 1, the risk level is the first level, when the number of risk factors is 2 or 3, the risk level is the second level, when the number of risk factors is 4, the risk level is the third level, and the third level is higher than the second level and is higher than the first level.

2. The comprehensive prediction method of the risk level of fracturing-induced hydrocarbon casing deformation according to claim 1, wherein the establishing a block-refined stress field comprises the steps of:

according to a technical method of 'well-seismic combination', on the basis of seismic wave data, a three-dimensional geological model of a target block is established by combining single-well horizon information;

calculating rock mechanical parameters according to the logging data of a single well in the target block, and performing single-well geomechanical analysis on other logging data and rock mechanical parameters to obtain a single-well geomechanical analysis result;

comprehensively analyzing information of a world stress map, single well measurement information of existing wells and horizontal well fracturing microseism monitoring information in a target block to obtain a maximum horizontal principal stress direction angle in the target block;

introducing a three-dimensional geological model, establishing a ground stress field finite element model of a target block, verifying a simulation result of the ground stress field of the target block based on a single well geological analysis result and a microseism actual measurement result of an existing well during fracturing construction, and solving the verified ground stress field value to construct a block fine ground stress field.

3. The method of comprehensively predicting the risk level of fracturing-induced oil and gas casing deformation according to claim 2, wherein the building of the three-dimensional geological model of the target block based on the seismic wave data in combination with single-well horizon information comprises: and establishing the grid geometric dimension of a geological model according to the three-dimensional seismic wave data, dividing the stratum and defining the size of grid units of each stratum, wherein the grid units of the stratum where the reservoir is located are smaller than those of other strata.

4. The method of comprehensively predicting the risk level of fracturing-induced casing deformation according to claim 3, wherein the ratio of the thickness of the grid cells of the formation where the reservoir is located to the thickness of the grid cells of the other formations is 1:18 to 1:30.

5. the method of claim 2, wherein the other well log data includes formation gamma ray, compressional acoustic duration and density, and the rock mechanics parameters include Young's modulus, poisson's ratio, cohesion and internal friction angle.

6. The method of claim 2, wherein the single well geological analysis results include geostress results obtained by indirect analysis using other well logging data and geostress results obtained by direct calculation using rock mechanics parameters.

7. The method of comprehensively predicting the risk level of fracturing induced casing deformation according to claim 2, wherein the comprehensively analyzing information of a world stress map, information of single well measurement of existing wells, and information of monitoring of horizontal well fracturing micro-seismic in a target block to obtain a maximum horizontal principal stress direction angle in the target block comprises:

judging the maximum horizontal principal stress direction angle of the area to which the target block belongs by using a world stress map, and determining the interval range to which the maximum horizontal principal stress direction angle in the target block belongs;

judging the interval range of the maximum horizontal principal stress direction angles of different structural parts in the target block according to the information measured by the single well, and determining the change rule of the maximum horizontal principal stress direction angles in the target block along with the terrain;

and analyzing the microseism monitoring information, verifying and correcting the value of the maximum horizontal principal stress direction angle in the target block summarized by using the world stress map and the single-well measurement information by combining the analysis result of the microseism monitoring information, and/or supplementing and correcting the value of the maximum horizontal principal stress direction angle in the target block of the leakage area lost by using the world stress map and the single-well measurement information.

8. The method of comprehensively predicting the risk level of fracturing-induced casing deformation of a hydrocarbon well according to claim 2, wherein the establishing a finite element model of the ground stress field of the target block comprises: setting units adopted by a geological model grid as three-dimensional 8-node linear units, setting the load of a ground stress field finite element model as a gravity load, setting boundary conditions of four sides and the bottom of the ground stress field finite element model as normal displacement constraints, setting boundary conditions of the top of the ground stress field finite element model as free boundaries, and setting initial ground stress parameters and initial pore pressure parameters as initial conditions, wherein the initial ground stress parameters comprise three-axis ground stress main components and a maximum horizontal main stress direction angle obtained by single-well geomechanical analysis.

9. The comprehensive prediction method for the risk level of fracturing-induced oil-gas casing deformation according to claim 6, wherein the verifying the simulation result of the geostress field of the target block based on the single-well geological analysis result and the actual measurement result of the micro-earthquake of the existing well during the fracturing construction, and the numerically solving of the geostress field qualified for verification into the block fine geostress field comprises:

for each single well of the target block, respectively utilizing the crustal stress result obtained by indirectly analyzing other logging data and the crustal stress result obtained by directly calculating rock mechanical parameters as initial crustal stress parameters to carry out numerical simulation on the crustal stress field of the target block to obtain a corresponding crustal stress field numerical solution;

and comparing the two kinds of numerical solutions of the ground stress field with the errors of the actual measurement values of the ground stress field in the existing well fracturing construction, and taking the numerical solution with a smaller error of the actual measurement values of the ground stress field as the block fine ground stress field.

10. The method of claim 1, wherein the local gamma curve local anomaly projection is determined based on a local gamma value greater than 200GAPI.

11. The comprehensive prediction method for the fracture-induced risk level of deformation of a hydrocarbon casing according to claim 1, wherein the judgment of the well cementation homogeneity abnormality is based on that the local acoustic amplitude value is higher than an interface with poor cement cementation and the local evaluation result of the well cementation quality is poor.

12. The comprehensive prediction method for the risk level of fracturing-induced oil and gas casing deformation according to claim 1, wherein the judgment basis of the maximum shear load point caused by the fracturing section where the construction pressure peak value is located is that the amplitude of sharp increase or sharp decrease of a pressure curve is more than 10MPa/min, and the pressure curve is not a straight line.

13. The method of comprehensively predicting the risk level of fracturing-induced casing deformation of a hydrocarbon casing of claim 1, wherein the location of the fracture-induced formation fracture zone is determined from pre-fracture geological data and/or numerical simulations of the reservoir fracture.

14. The method of claim 1, wherein the fracture-induced casing deformation risk level is increased when the local abnormal change in natural gamma and/or the local abnormal change in well cementation homogeneity at the fracture zone of the formation caused by the fracture.

15. The method of claim 1, wherein the risk factors of the casing include a fracture construction pressure curve sand plugging peak, and when the number of the risk factors is multiple, the level of the fracture-induced casing deformation risk level can be reduced by optimizing fracture construction parameters.

16. The method of comprehensively predicting the risk level of fracturing-induced casing deformation of a hydrocarbon well according to claim 1, wherein the probability of casing deformation is predicted to be 0 when the risk level is zero; when the risk degree is the first level, the probability prediction of casing deformation is less than or equal to 20 percent; when the risk degree is the second level, the probability prediction of casing deformation is 20-50%; the risk level is third level, and the probability of casing deformation is predicted to be more than 50%.