A method and system for analyzing oil and gas well instability during simultaneous kerosene and oil production

Abstract

This application relates to the technical field of coal mine exploitation, and provides a method and system for analyzing the instability of oil and gas wells during co-mining of coal and oil. In this method, for oil and gas wells under non-mining conditions, when the actual dip angle β of the weak plane of the oil and gas well rock formation is greater than the critical dip angle of the weak plane of the oil and gas well rock formation, the ultimate horizontal stress σ1 of the oil and gas well rock formation under non-mining conditions obtained based on the pre-constructed Jaeger weak plane correction model is compared with the measured horizontal stress σ′1 in the rock formation where the oil and gas well is located, and the instability of the oil and gas well is judged according to the comparison result; for oil and gas wells under mining conditions, the stability of the oil and gas well is evaluated according to the constructed instability discrimination model of the oil and gas well under mining conditions. By analyzing the influence of the cohesion of the weak plane on the mechanical behavior of the rock formation under biaxial and triaxial stress conditions, the stability of the gas well is evaluated, and further guidance is provided for the prediction and evaluation of the stability of oil and gas wells and the drilling design of oil and gas wells under the condition of co-mining of coal and oil.

Description

Technical Field

[0001] The present application relates to the technical field of coal mining, and in particular to a method and system for analyzing instability of oil and gas wells during simultaneous coal and oil mining. Background Art

[0002] Gas wells are conduits for the extraction of hydrocarbon resources deep in the earth, such as coalbed methane, shale gas, sandstone gas, and shale oil, and it is very important to prevent gas well instability. In some sedimentary basins, coal coexists with these hydrocarbon resources, and in most cases the coal seams are located above the gas reservoirs. Coal seam mining causes stratum movement, especially when high-intensity mining methods such as longwall mining are used, which can cause damage to gas wells. The vulnerability of gas well instability can endanger gas production, or cause gas well seal failure, or even leak explosive gas into the mining space. When the mine working face approaches the gas well, the gas well is usually sealed to prevent gas from leaking into the mined space, and the instability of the gas well is prevented by improving the stability of the gas well that penetrates the coal seam.

[0003] Gas well instability can be classified into four types: shear, deformation, tension and compression, corresponding to different mechanisms of formation deformation caused by coal mining. Under the influence of longwall mining, the formation deforms both downward and horizontally, which are defined as conventional settlement and unconventional settlement, respectively. Unconventional settlement is a response to shear displacement or slip at weak surfaces in stratified formations and may cause the most serious damage to the wellbore of the gas well. Shear displacement or slip at weak surfaces usually occurs under low friction coefficients or low normal stresses acting on the weak surfaces. In addition, horizontal displacement of the formation is not only related to low friction and low normal stresses, but also to the horizontal stress release effect caused by the formation of nearby longwall goafs. In this case, the horizontal displacement can extend far in the horizontal direction, deep into the overburden and away from the goaf.

[0004] Conventional subsidence threatens the integrity of gas wells by introducing separation or compression of bedding planes. Separation and compression of bedding planes are mainly affected by rock properties, stratigraphic structure, and the stress state caused by mining activities. Beddings containing strong bedding planes usually deform as units or groups. In theory, the location of bedding plane separation above the goaf can be evaluated based on the typical three-zone theory (caving zone, crushing zone, deformation zone). Under the support stress caused by excavation, the strength of bedding planes not only determines the overall strength of the layered rock, but has also been shown to change the instability type of the layered rock from tension to shear.

[0005] At the same time, lamination is another major factor threatening the protection of gas wells. The increase in the vertical load of the well column caused by the addition of the support load usually causes axial compression of the gas well along with the deformation of the layered strata, especially in the case of different bedding stiffness. Especially under high vertical loads, shear bands accompanied by compaction may form at the bedding plane. When this happens, it will cause axial deformation together with the shear displacement of the bedding plane. Summary of the invention

[0006] The purpose of the present application is to provide a method and system for analyzing oil and gas well instability during simultaneous production of kerosene and oil, so as to solve or alleviate the problems existing in the above-mentioned prior art.

[0007] In order to achieve the above objectives, this application provides the following technical solutions:

[0008] The present application provides an instability analysis method for oil and gas wells during simultaneous production of kerosene and oil, comprising: in response to the oil and gas well being in a non-production condition, comparing the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition obtained based on a pre-constructed Jaeger weak plane correction model with the measured horizontal stress σ′1 of the rock formation of the oil and gas well, and making an instability judgment on the oil and gas well based on the comparison result; in response to the oil and gas well being in a production condition, making an instability judgment on the oil and gas well based on a pre-constructed oil and gas well instability judgment model.

[0009] Preferably, in response to the oil and gas well being located in a non-production condition, the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the production condition obtained based on the pre-constructed Jaeger weak plane correction model is compared with the actually measured horizontal stress σ′1 of the rock formation of the oil and gas well, and the oil and gas well is judged to be unstable based on the comparison result, including: in response to the oil and gas well being located in a non-production condition, the Jaeger weak plane theoretical model is corrected according to multiple groups of physical and mechanical parameters of multiple combined rock samples of the rock formation of the oil and gas well obtained to obtain the Jaeger weak plane correction model; based on the Jaeger weak plane correction model, the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition is determined; in response to the ultimate horizontal stress σ1 of the rock formation of the oil and gas well being greater than the actually measured horizontal stress σ′1 of the rock formation of the oil and gas well, the oil and gas well becomes unstable under the non-production condition.

[0010] Preferably, in response to the oil and gas well being located in a non-production condition, the Jaeger weak plane theoretical model is corrected according to multiple groups of physical and mechanical parameters of multiple combined rock samples of the oil and gas well rock formations to obtain the Jaeger weak plane corrected model, including: in response to the oil and gas well being located in a non-production condition, the actual weak plane inclination β of the oil and gas well rock formation is greater than the theoretical weak plane inclination of the oil and gas well rock formation, fitting the fitting parameter sets of the multiple combined rock samples obtained, constructing a correction function to correct the Jaeger weak plane theoretical model to obtain the Jaeger weak plane corrected model; wherein the fitting parameter set includes the weak plane roughness ratio, bonding strength and vertical stress of each combined rock sample.

[0011] Preferably, according to the formula:

[0012]

[0013] Determine the theoretical weak plane inclination angle β' of the oil and gas well rock formation; where σ3 is the vertical stress of the oil and gas well rock formation; C p is the bonding strength of the oil and gas well rock formation; μ p is the weak surface friction coefficient of the oil and gas well rock formation, C0 is the bedding matrix cohesion of the oil and gas well rock formation; β0 is an intermediate variable, and μ0 is the internal friction coefficient of the bedding matrix of the oil and gas well rock formation.

[0014] Preferably, the Jaeger weak surface correction model is:

[0015] σ1=2C0tanβ+σ3tan 2 β+f(g λ , C p ,σ3)

[0016] Wherein, σ1 is the ultimate horizontal stress of the oil and gas well rock formation; C0 is the bedding matrix cohesion of the oil and gas well rock formation; β is the actual weak surface inclination angle of the oil and gas well rock formation; f(g λ , C p , σ3) is the correction function, g λ is the roughness ratio of the weak surface of the oil and gas well rock formation, C p is the bonding strength of the oil and gas well rock formation, and σ3 is the vertical stress of the oil and gas well rock formation.

[0017] Preferably, the oil and gas well instability discrimination model is:

[0018]

[0019] In the formula, C p is the bonding strength of the oil and gas well rock formation; μ p is the weak surface friction coefficient of the oil and gas well rock formation; σv is the measured vertical stress of the rock formation of the oil and gas well; △σ v is the measured vertical stress change value of the oil and gas well rock formation; E1 and E2 are the elastic moduli of the upper and lower rock formations forming the bedding plane of the oil and gas well rock formation, and E1 <E2;△σ h is the change value of the horizontal stress of the rock formation of the oil and gas well.

[0020] An embodiment of the present application also provides an instability analysis system for oil and gas wells during simultaneous production of kerosene and coal, comprising: a non-production instability judgment unit, configured to, in response to the oil and gas well being in a non-production condition, compare the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition obtained based on a pre-constructed Jaeger weak surface correction model with the measured horizontal stress σ′1 of the rock formation of the oil and gas well, and make an instability judgment on the oil and gas well based on the comparison result; and a production instability judgment unit, configured to, in response to the oil and gas well being in a production condition, make an instability judgment on the oil and gas well based on a pre-constructed oil and gas well instability judgment model.

[0021] Beneficial effects:

[0022] In the instability analysis method for oil and gas wells during simultaneous production of kerosene and oil provided in an embodiment of the present application, for oil and gas wells under non-production conditions, when the actual weak plane inclination angle β of the oil and gas well rock formation is greater than the theoretical weak plane inclination angle of the oil and gas well rock formation, the ultimate horizontal stress σ1 of the oil and gas well rock formation under non-production conditions obtained based on the pre-constructed Jaeger weak plane correction model is compared with the measured horizontal stress σ′1 of the oil and gas well rock formation, and the instability of the oil and gas well is judged based on the comparison result; for oil and gas wells under production conditions, the stability of the oil and gas wells is evaluated based on the constructed oil and gas well instability discrimination model under production conditions, thereby evaluating the stability of the gas well by analyzing the influence of the bedding plane bonding strength on the mechanical behavior of the synthetic layered rock under biaxial and triaxial stress conditions, thereby providing guidance for gas well drilling design based on the bedding plane parameters of the layered formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0024] in:

[0025] Figure 1 A schematic flow chart of an oil and gas well instability analysis method during simultaneous kerosene and oil production according to some embodiments of the present application:

[0026] Figure 2 A schematic diagram of stress changes in surrounding rocks of oil and gas wells under non-mining conditions provided according to some embodiments of the present application;

[0027] Figure 3 A schematic diagram of changes in surrounding rock stress of oil and gas wells caused by longwall mining under mining conditions according to some embodiments of the present application;

[0028] Figure 4 The present invention is a schematic structural diagram of an oil and gas well instability analysis system for simultaneous kerosene and oil production according to some embodiments of the present application. DETAILED DESCRIPTION

[0029] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as a part of an embodiment may be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the embodiments of the present invention should belong to the scope of protection of the embodiments of the present invention.

[0030] In the study of gas well stability, there is a lack of analysis on the interaction between stress changes and bedding plane parameters. The strength parameters of bedding planes, such as tensile strength and bonding strength, significantly affect the instability behavior of layered rocks. However, in existing studies, the influence of bedding plane strength is considered only under uniaxial compression or tensile stress conditions, which is far from the in-situ stress of the protective column near the goaf.

[0031] Based on this, this application specifically analyzes the effect of bedding plane bond strength on the mechanical behavior of synthetic layered rocks under biaxial and triaxial stress conditions (instability stress, instability mode and deformability) to evaluate gas well stability and provide guidance for gas well drilling design based on bedding plane parameters of layered formations. Figures 1 to 3 As shown, the oil and gas well instability analysis method during kerosene and oil production includes:

[0032] Step S101, in response to the oil and gas well being in a non-production condition, the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition obtained based on the pre-constructed Jaeger weak plane correction model is compared with the measured horizontal stress σ′1 of the rock formation of the oil and gas well, and the oil and gas well is judged to be instability based on the comparison result.

[0033] According to the Jaeger weak plane theoretical model, when the weak plane inclination angle of layered rock is 90 degrees, the theoretical strength of layered rock will not increase with the bond strength C pThe weak plane surface geometry does not change, but only depends on the bedding matrix and potential pressure. This is because under ideal conditions, the surface geometry of the weak plane is not taken into account. However, the complex surface geometry of the weak plane includes small-scale roughness components and large-scale waviness components. The interaction of weak plane roughness will affect the strength of the rock mass under shear and compression loads; for example, in a transversely isotropic model, the roughness of the weak plane will lead to an increase in the uniaxial compressive strength of the transversely isotropic model.

[0034] Due to the interaction between the wavyness and roughness on the bedding plane (weak plane), the strength of the layered rock decreases with the bond strength C when the weak plane inclination is close to 90 degrees. p As the roughness increases, the interaction between the roughness and the rock mass affects its mechanical properties by changing the stress distribution in the rock mass under external load. Specifically, according to the formula:

[0035]

[0036] Determine the theoretical weak plane inclination angle β' of the oil and gas well formation. Where σ3 is the vertical stress of the oil and gas well formation; C p is the bonding strength of the oil and gas well rock formation; μ p is the weak surface friction coefficient of the oil and gas well rock formation, C0 is the cohesion of the bedding matrix of the oil and gas well rock formation; p0 is the intermediate variable, μ0 is the internal friction coefficient of the bedding matrix of the oil and gas well rock formation.

[0037] When the actual weak plane dip angle β of the oil and gas well rock formation is less than or equal to the theoretical weak plane dip angle β' of the oil and gas well rock formation, the Jaeger weak plane theoretical model can be used to predict the failure of layered rocks; however, when the actual weak plane dip angle β of the oil and gas well rock formation is greater than the theoretical weak plane dip angle β' of the oil and gas well rock formation, due to the interaction between the waviness and roughness on the bedding plane (weak plane), the Jaeger weak plane theoretical model needs to be corrected, and the failure of layered rocks is predicted by the Jaeger weak plane corrected model.

[0038] Specifically, when the oil and gas well is located in a non-production condition, the Jaeger weak plane theoretical model is corrected according to multiple sets of physical and mechanical parameters of multiple combined rock samples of the oil and gas well rock formations, and the Jaeger weak plane correction model is obtained. That is to say, for oil and gas wells under non-production conditions, first, the adjacent rock formations with potential slip instability are sampled (the adjacent rock formations within a diameter of 50 meters with the oil and gas well as the center) to obtain multiple combined rock samples of the oil and gas well rock formations; then, the physical and mechanical parameters of the multiple combined rock samples obtained are measured in the laboratory, including at least the bedding matrix cohesion of the combined rock sample, the actual weak plane inclination of the combined rock sample, the weak plane roughness ratio of the combined rock sample, the bonding strength of the combined rock sample, and the vertical stress of the combined rock sample; then, the fitting parameter sets of the obtained multiple combined rock samples are fitted to obtain the correction function f. Among them, the fitting parameter set is a data set of the weak plane roughness ratio, bonding strength, and vertical stress of each combined rock sample.

[0039] Furthermore, based on the obtained fitting function f(g λ , C p ,σ3) construct the Jaeger weak surface correction model. Specifically, the Jaeger weak surface correction model is:

[0040] σ1=2C0tanβ+σ3tan 2 β+f(g λ , C p ,σ3)

[0041] Where σ1 is the ultimate horizontal stress of the oil and gas well formation; C0 is the cohesion of the bedding matrix of the oil and gas well formation; β is the actual weak surface inclination angle of the oil and gas well formation; f(g λ , C p , σ3) is the roughness ratio of the weak surface to the oil and gas well rock formation g λ , bonding strength C p And the correction function related to the vertical stress σ3.

[0042] Generally, for oil and gas wells with different geological conditions (including at least depth, average density, internal friction angle, etc.), the weak surface roughness ratio g of the oil and gas well rock formation is λ , bonding strength C p , vertical stress σ3 is different. Specifically, according to the formula:

[0043]

[0044] Determine the bond strength C of the rock formation in oil and gas wells p and vertical stress σ3. Where C0 is the cohesion of the bedding matrix of the oil and gas well formation, ρ is the average density of the oil and gas well formation, and g is a constant, g≈9.81m / s 2, h is the depth of the oil and gas well rock formation; φ is the internal friction angle of the oil and gas well rock formation.

[0045] For oil and gas wells with different geological conditions, the average density ρ will vary with depth, lithology, temperature, etc. For surface soil and sediments, ρ = 2000 ~ 2500 kg / m 3 For igneous rocks (such as granite), ρ = 2500 ~ 2800 kg / m 3 For metamorphic rocks (such as gneiss), ρ = 2700 ~ 3000 kg / m 3 For sedimentary rocks (such as limestone and sandstone), ρ = 2200-2800 kg / m 3 .

[0046] The internal friction angle of oil and gas well rock formations usually depends on the type and geology of the rock. For sandstone, φ = 30° ~ 40°, for shale, φ = 20° ~ 30°, for limestone, φ = 25° ~ 35°, for granite, φ = 40° ~ 50°, and for coal seams, φ = 20° ~ 30°.

[0047] Weak surface roughness ratio g of oil and gas well rock formation λ It is the ratio of the average roughness height of the weak surface to its length, reflecting the degree of concavity and convexity of the weak surface of the oil and gas well rock formation. For a smooth weak surface (for example, a flat fault surface), the weak surface roughness ratio g λ <1, for medium roughness weak surface (for example, normal fracture surface of rock formation), the weak surface roughness ratio g λ = 1 to 3, for rough weak surfaces with obvious irregular cracks or faults, the roughness ratio of the weak surface is g λ >3. Roughness ratio of weak surface of oil and gas well rock formation under different geological conditions g λ The roughness ratio of the weak surface of the rock formation in the oil and gas well g is obtained by contact measurement of the rock sample in the laboratory. λ =0.5~1.5.

[0048] Therefore, for oil and gas wells and rock formations under different geological conditions, the fitting function f(g λ , C p The specific expression of σ3) is different and needs to be obtained by parameter fitting after sampling the rock formation of the oil and gas well. The average density of the rock formation in the oil and gas well is ρ = 2500kg / m 3 , bonding strength C = 500Kpa, weak surface inclination angle β = 0°, internal friction angle φ = 30°, the weak surface roughness ratio g λ = 0.7 for oil and gas well formations, the fitting function f(g λ , C p , σ3) is specifically expressed as:

[0049]

[0050] Finally, according to the Jaeger weak plane correction model, the ultimate horizontal stress σ1 of the oil and gas well rock formation (the oil and gas well to be evaluated) under non-production conditions is calculated, and the ultimate horizontal stress σ1 of the oil and gas well rock formation (the oil and gas well to be evaluated) is compared with the measured horizontal stress σ′1 of the oil and gas well rock formation (the oil and gas well to be evaluated) obtained by in-situ ground stress testing, and the oil and gas well (the oil and gas well to be evaluated) is judged to be unstable based on the comparison results. When the ultimate horizontal stress σ1 of the oil and gas well rock formation (the oil and gas well to be evaluated) is greater than the measured horizontal stress σ′1 of the oil and gas well rock formation (the oil and gas well to be evaluated), the oil and gas well (the oil and gas well to be evaluated) is unstable; when the ultimate horizontal stress σ1 of the oil and gas well rock formation (the oil and gas well to be evaluated) is less than or equal to the measured horizontal stress σ′1 of the oil and gas well rock formation (the oil and gas well to be evaluated), the oil and gas well (the oil and gas well to be evaluated) will not be unstable, that is, the wellbore of the oil and gas well (the oil and gas well to be evaluated) is stable.

[0051] Step S102: in response to the oil and gas well being in a production condition, the oil and gas well is judged to be instability based on a pre-built oil and gas well instability judgment model.

[0052] As a typical mechanism of gas well instability, the compression instability of gas wells is closely related to the vertical strain of the formation bedding. The compression instability of layered rocks interacts with the strength of the bedding plane, and the shear-accompanying compression phenomenon only occurs when the bonding strength C p In lower rock layers, this may not only cause gas well instability, but also hinder the flow of underground gas. In underground environments, the strength of bedding planes (weak planes) varies with geological conditions. Usually, when strong rock units are in contact with weak rock units (for example, clay in contact with sandstone), the strength of the bedding planes is low, and the possibility of oil and gas well instability increases.

[0053] Advancement of longwall coal face under mining conditions and its relationship with bond strength C p In the horizontal direction, the coal seam after mining and the roof fall and deformation zone caused by it lose their constraints, and the in-situ horizontal stress decreases significantly, that is, the horizontal stress of the rock formation of the oil and gas well changes (the change value is △σ v ). At this time, the difference in elastic modulus of adjacent rock layers will cause different displacements of different rock layers, thereby generating shear forces between bedding planes. The rock layer where the gas well is located will be shear deformed or even damaged due to bedding plane slippage.

[0054] On the other hand, the support load caused by longwall mining will lead to an increase in vertical stress, that is, the vertical stress of the oil and gas well formation changes (the change value is △σ h), when it is determined that the bedding plane slip occurs, the upper and lower rock layers (elastic moduli are E1 and E2 respectively) of the bedding plane of the oil and gas well rock formation form a bonded cantilever beam, and the potential displacements △L1 and △L2 of the rock units in the two rock layers are respectively:

[0055]

[0056] Where L0 is the horizontal distance between the mining coal seam tunnel and the oil and gas well, and E1 <E2。

[0057] If the gas well slips and becomes unstable, and the horizontal stress acting on the two adjacent rock layers on the bedding plane is completely released, the displacement difference △L between the two adjacent rock layers on the bedding plane is:

[0058]

[0059] Therefore, the shear stress τ on the bedding plane is:

[0060]

[0061] Furthermore, a model for distinguishing oil and gas well instability under mining conditions is established:

[0062]

[0063] In the formula, C p is the bonding strength of the oil and gas well rock formation; μ p is the weak surface friction coefficient of the oil and gas well formation; σ v is the measured horizontal stress of the rock formation in the oil and gas well; △σ v is the measured vertical stress change value of the oil and gas well rock formation; E1 and E2 are the elastic moduli of the upper and lower rock formations forming the bedding plane of the oil and gas well rock formation; △σ h is the horizontal stress change value of the oil and gas well rock formation.

[0064] That is to say, under mining conditions, the target rock formation of the oil and gas well is sampled and tested in the laboratory to obtain the bonding strength C of the rock formation of the oil and gas well. p , weak surface friction coefficient μ p , horizontal stress σ v The elastic modulus E1 and E2 of the two rock layers above and below the bedding plane are measured, and the horizontal stress change value △σ of the rock layer of the oil and gas well caused by mining is obtained by conducting in-situ ground stress test near the wellbore position (within 50m) h and vertical stress change △σ v ; Then, the measured rock formation parameters of the oil and gas wells are substituted into the oil and gas well instability discrimination model under production conditions. When the measured rock formation parameters of the oil and gas wells meet the oil and gas well instability discrimination model under production conditions, the oil and gas wells will remain stable after production occurs, otherwise the oil and gas wells will become unstable after production occurs.

[0065] Therefore, for oil and gas wells under non-production conditions, the Jaeger weak plane theoretical model is corrected through the interaction of bedding plane parameters (bonding strength and weak plane roughness) that affect the instability behavior of layered rocks, so that the corrected Jaeger weak plane correction model can more accurately evaluate the influence of the mechanical behavior of layered rocks (instability stress, instability mode and deformability); at the same time, for oil and gas wells under production conditions, the stability of gas wells is evaluated through the constructed oil and gas well instability discrimination model under production conditions, providing guidance for gas well drilling design according to the bedding plane parameters of layered strata.

[0066] Here, it should be noted that there is no sequential relationship between step S101 and step S102. For oil and gas wells under non-production conditions, instability judgment is performed according to step S101, and for oil and gas wells under production conditions, instability judgment is performed according to step S102.

[0067] like Figure 4 As shown, the embodiment of the present application also provides an oil and gas well instability analysis system during kerosene and oil production, comprising:

[0068] The non-production instability judgment unit 401 is configured to compare the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the production condition obtained based on the pre-built Jaeger weak plane correction model with the measured horizontal stress σ′1 of the rock formation of the oil and gas well in response to the oil and gas well being in the non-production condition, and to judge the instability of the oil and gas well according to the comparison result:

[0069] The production instability judgment unit 402 is configured to make an instability judgment on the oil and gas well based on a pre-built oil and gas well instability judgment model in response to the oil and gas well being in a production condition.

[0070] The system for analyzing instability of oil and gas wells during simultaneous kerosene and oil production provided in the embodiments of the present application can implement the steps and processes of the method for analyzing instability of oil and gas wells during simultaneous kerosene and oil production of any of the above embodiments, and achieve the same technical effects, which will not be described in detail here.

[0071] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0075] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0076] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing instability of oil and gas wells during simultaneous production of kerosene and oil, characterized in that: include: In response to the oil and gas well being in a non-production condition, the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition obtained based on the pre-constructed Jaeger weak plane correction model is compared with the measured horizontal stress σ′1 of the rock formation of the oil and gas well, and the oil and gas well is judged to be unstable according to the comparison result; wherein the Jaeger weak plane correction model is: σ1=2C0tanβ+σ3tan 2 β+f(g λ ,C p ,σ3) Where, C0 is the cohesion of the bedding matrix of the oil and gas well formation; β is the actual weak surface inclination angle of the oil and gas well formation; f(g λ ,C p ,σ3) is the correction function, g λ is the roughness ratio of the weak surface of the oil and gas well rock formation, C p is the bonding strength of the oil and gas well rock formation, σ3 is the vertical stress of the oil and gas well rock formation; In response to the oil and gas well being in a production condition, the oil and gas well is judged to be instability based on a pre-constructed oil and gas well instability discrimination model; wherein the oil and gas well instability discrimination model is: In the formula, μ p is the weak surface friction coefficient of the oil and gas well rock formation; σ v is the measured vertical stress of the rock formation of the oil and gas well; Δσ v is the measured vertical stress change value of the oil and gas well rock formation; E1 and E2 are the elastic moduli of the upper and lower rock formations forming the bedding plane of the oil and gas well rock formation, and E1 <E2;Δσ h is the change value of the horizontal stress of the rock formation of the oil and gas well.

2. The method for analyzing instability of oil and gas wells during simultaneous kerosene and oil production according to claim 1, characterized in that: In response to the oil and gas well being in a non-production condition, the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the production condition obtained based on the pre-constructed Jaeger weak plane correction model is compared with the measured horizontal stress σ′1 of the rock formation of the oil and gas well, and the instability of the oil and gas well is judged according to the comparison result, including: In response to the oil and gas well being in a non-production condition, the Jaeger weak plane theoretical model is corrected according to multiple groups of physical and mechanical parameters of multiple combined rock samples of the oil and gas well rock formations to obtain the Jaeger weak plane corrected model; Based on the Jaeger weak plane correction model, determining the ultimate horizontal stress σ1 of the oil and gas well rock formation under non-mining conditions; In response to the ultimate horizontal stress σ1 of the rock formation of the oil and gas well being greater than the measured horizontal stress σ′1 of the rock formation of the oil and gas well being, the oil and gas well is unstable under non-production conditions.

3. The method for analyzing instability of oil and gas wells during simultaneous kerosene and oil production according to claim 2, characterized in that: In response to the oil and gas well being in a non-production condition, the Jaeger weak plane theoretical model is corrected according to multiple groups of physical and mechanical parameters of multiple combined rock samples of the oil and gas well rock formations to obtain the Jaeger weak plane corrected model, including: In response to the oil and gas well being located in a non-production condition, the actual weak plane inclination angle β of the oil and gas well rock formation is greater than the theoretical weak plane inclination angle of the oil and gas well rock formation, the fitting parameter sets of the multiple combined rock samples obtained are fitted, and the correction function is constructed to correct the Jaeger weak plane theoretical model to obtain the Jaeger weak plane correction model; wherein the fitting parameter set includes the weak plane roughness ratio, bonding strength and vertical stress of each combined rock sample.

4. The method for analyzing instability of oil and gas wells during simultaneous kerosene and oil production according to claim 3, characterized in that: According to the formula: Determine the theoretical weak plane dip angle β' of the oil and gas well rock formation; Wherein, σ3 is the vertical stress of the oil and gas well rock formation; C p is the bonding strength of the oil and gas well rock formation; μ p is the weak surface friction coefficient of the oil and gas well rock formation, and C0 is the bedding matrix cohesion of the oil and gas well rock formation; β0 is an intermediate variable, and μ0 is the friction coefficient within the bedding matrix of the oil and gas well rock formation.

5. An oil and gas well instability analysis system for simultaneous kerosene and oil production, characterized in that: include: The non-production instability judgment unit is configured to compare the ultimate horizontal stress σ1 of the rock formation of the oil and gas well under the non-production condition obtained based on the pre-constructed Jaeger weak plane correction model with the measured horizontal stress σ′1 of the rock formation of the oil and gas well in response to the oil and gas well being in the non-production condition, and to judge the instability of the oil and gas well according to the comparison result; wherein the Jaeger weak plane correction model is: σ1=2C0tanβ+σ3tan 2 β+f(g λ ,C p ,σ3) Where, C0 is the cohesion of the bedding matrix of the oil and gas well formation; β is the actual weak surface inclination angle of the oil and gas well formation; f(g λ ,C p ,σ3) is the correction function, g λ is the roughness ratio of the weak surface of the oil and gas well rock formation, C p is the bonding strength of the oil and gas well rock formation, σ3 is the vertical stress of the oil and gas well rock formation; The mining instability judgment unit is configured to judge the instability of the oil and gas well based on a pre-built oil and gas well instability judgment model in response to the oil and gas well being in a mining condition; wherein the oil and gas well instability judgment model is: In the formula, μ p is the weak surface friction coefficient of the oil and gas well rock formation; σ v is the measured vertical stress of the rock formation of the oil and gas well; Δσ v is the measured vertical stress change value of the oil and gas well rock formation; E1 and E2 are the elastic moduli of the upper and lower rock formations forming the bedding plane of the oil and gas well rock formation, and E1 <E2;Δσ h is the change value of the horizontal stress of the rock formation of the oil and gas well.

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