CN113969782A - Method for predicting anisotropic fracture pressure and method for preventing formation fracture - Google Patents
Method for predicting anisotropic fracture pressure and method for preventing formation fracture Download PDFInfo
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Abstract
The invention provides a method for predicting anisotropic fracture pressure and a method for preventing stratum fracture. A method for predicting anisotropic burst pressure, comprising: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model; determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth; determining the effective stress of a target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress; determining the uniaxial compressive strength of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength; and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model. The present embodiment can accurately predict the fracture pressure of the target layer in consideration of anisotropy.
Description
Technical Field
The invention relates to the fields of geomechanics and logging engineering, in particular to a prediction method of anisotropic fracture pressure and a method for preventing stratum fracture.
Background
The stratum fracture pressure is an important basis for reasonably determining the well structure, safely drilling, determining the fracturing construction pressure and the like. The parameter can be obtained by indoor rock mechanics experiment or hydraulic fracturing construction in oil and gas well site, and the stratum fracture pressure can be extracted from logging data. At present, the method and the technology for estimating the fracture pressure of the sand shale profile stratum by using logging information are mature. However, since anisotropy exists widely in the stratum, and the strength of different structural parts under the action of the structural stress is difficult to determine, the measurement of the minimum level principal stress and the tensile strength of the rock mass is difficult, so that the fracture pressure calculated by using logging data is inaccurate.
Many prediction models for formation fracture pressure have been reported at home and abroad, including Eaton models, Anderson models, Huangronzun models and the like. However, these models have specific applicable conditions, and the assumptions of the existing prediction models for anisotropic reservoirs (such as shale gas reservoirs) include that the overlying pressure gradient is constant, the tensile strength is 0, the horizontal structural principal stress is uniform, and the rock is isotropic, which is not true. For example, the huangrong goblet model is an advanced fracture pressure prediction model, which considers the influences of pore pressure, rock tensile strength, tectonic stress, borehole wall stress concentration and the like, and is an isotropic prediction model, but the huangrong goblet model does not consider the anisotropy of the rock and is theoretically inapplicable for the reservoir with anisotropic development, such as a shale gas reservoir.
Therefore, it is necessary to establish a fracture pressure prediction model considering rock anisotropy.
Disclosure of Invention
The invention mainly aims to provide a method for predicting anisotropic fracture pressure and a method for preventing stratum from fracturing, so as to solve the problem of predicting the fracture pressure under the condition of considering rock anisotropy.
In a first aspect, an embodiment of the present application provides a method for predicting an anisotropic fracture pressure, including the steps of: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model; determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth; determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir; determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir; and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
In one embodiment, the anisotropic burst pressure prediction model is expressed as:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
In one embodiment, determining overburden pressure for a target reservoir includes:
determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
In one embodiment, determining the effective stress of the target reservoir based on the compressional velocity of the target reservoir comprises:
determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively, the effective stress and the seismic velocity of the target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress.
In one embodiment, determining the pore pressure of the target reservoir from the overburden pressure and the effective stress of the target reservoir comprises: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir and σ is the effective stress of the target reservoir.
In one embodiment, determining the uniaxial compressive strength of the target reservoir based on the shale content of the target reservoir comprises:
determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
the method comprises the following steps of A, obtaining a reservoir stratum, wherein UCS is the uniaxial compressive strength of the target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is the empirical coefficient for the tensile strength of the target reservoir.
In a second aspect, embodiments of the present application provide a method of preventing formation fracturing while drilling, comprising the steps of: predicting the anisotropic fracture pressure of the target reservoir according to the anisotropic fracture pressure prediction method; determining a fracture pressure coefficient of the target reservoir according to the anisotropic fracture pressure of the target reservoir; determining the maximum mud density of the injected mud during drilling according to the corresponding relation between the fracture pressure coefficient of the target reservoir and the maximum mud density; the density of the injected mud is controlled to not exceed the maximum mud density while drilling to prevent formation fracture.
In one embodiment, determining a fracture pressure coefficient from the anisotropic fracture pressure of the target reservoir comprises: the ratio of the anisotropic fracture pressure to the hydrostatic pressure of the target reservoir is determined as the fracture pressure coefficient.
In a third aspect, embodiments of the present application provide a storage medium storing a computer program which, when executed by a processor, implements the steps of the method for predicting an anisotropic fracture pressure as described above or the method for preventing formation fractures while drilling as described above.
In a fourth aspect, embodiments of the present application provide a computer apparatus comprising a processor and a storage medium having program code stored thereon, which when executed by the processor, implement the steps of the method of predicting anisotropic fracture pressure as described above or the method of preventing formation fractures while drilling as described above.
In a fifth aspect, an embodiment of the present application provides an apparatus for predicting an anisotropic burst pressure, including: the model establishing module is used for establishing an anisotropic fracture pressure prediction model of the target reservoir based on the Huangronzun model according to the elastic stiffness matrix describing the anisotropy of the rock; the overburden pressure determining module is used for determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth; the pore pressure determining module is used for determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir based on the Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir; the tensile strength determining module is used for determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir; and the fracture pressure determining module is used for determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
The invention considers the anisotropy into a Huangrong bottle fracture pressure model and establishes a more comprehensive shale anisotropy fracture pressure prediction model. The method provides basis for reasonably determining the well structure, safely drilling, determining the fracturing construction pressure and the like.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, it should be apparent that the drawings in the following description are only some embodiments of the present disclosure, and the accompanying drawings that form a part of this application and are included to provide further understanding to those skilled in the art, and the illustrative embodiments of the present disclosure and the description thereof are used to explain the present disclosure and do not constitute a limitation of the present disclosure, in which:
FIG. 1 is a flow chart of a method of predicting anisotropic burst pressure according to an exemplary embodiment of the present application;
FIG. 2 is a graph showing the results of the anisotropic burst pressure prediction method and Huangronzun model for a well;
fig. 3 is a schematic structural diagram of an anisotropic burst pressure prediction apparatus according to an exemplary embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Example one
Fig. 1 is a flowchart of a method of predicting anisotropic burst pressure according to an exemplary embodiment of the present application. As shown in fig. 1, the present embodiment provides a method for predicting an anisotropic rupture pressure, including the following steps:
s100: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model;
s200: determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
s300: determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
s400: determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
s500: and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
The invention considers the anisotropy into a Huangrong bottle fracture pressure model and establishes a more comprehensive shale anisotropy fracture pressure prediction model. The model can accurately predict and consider the target layer fracture pressure of anisotropy, and provides basis for reasonably determining a well structure, safely drilling, determining the fracturing construction pressure and the like.
Example two
As shown in fig. 1, the method for predicting an anisotropic fracture pressure provided in this embodiment may be specifically implemented by the following steps:
s100: and establishing an anisotropic fracture pressure prediction model of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock based on the Huangrong model.
The expression for the anisotropic burst pressure prediction model may be:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpRepresenting the pore pressure of the target reservoir, C13 and C33 are elements of an elastic stiffness matrix describing rock anisotropy, k is a formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
S200: and determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth.
Determining overburden pressure of a target reservoir may include: determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
In actual logging, the density curve is not always available in the whole well section, and the density curve of a shallow stratum is often lost. The density of the shallow stratum can be complemented by an empirical formula of density variation with depth, such as an Amoco empirical formula, or given an empirical value according to regional conditions.
Analyzing conditions such as geological background, lithology characteristics, well logging curves and the like of the work area, measuring the depth, longitudinal wave speed and well logging curves of the target reservoir, and explaining the well logging curves to obtain parameters such as the change of the density of the target reservoir along with the depth, the shale content of the target reservoir and the like.
S300: and based on the Eaton method, determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir.
The use of the Eaton method to calculate pore pressure is a widely used method in the industry. Determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir may include: determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively the effective stress and seismic velocity of a target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress, and the value is generally 2. SigmanormalMay be obtained by subtracting the hydrostatic pressure from the overburden pressure, VnormalMay be obtained by constructing a normal compaction trend line,
determining the pore pressure of the target reservoir from the overburden pressure and the effective stress of the target reservoir may include: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir and σ is the effective stress of the target reservoir.
S400: and determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir.
Determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir may include: determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
wherein UCS (Uniaxial Compression Strength) is the uniaxial compressive strength of a target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is an empirical coefficient, depending on the rock type, for the tensile strength of the target reservoir.
S500: and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
The invention considers the anisotropy into a Huangrong bottle fracture pressure model and establishes a more comprehensive shale anisotropy fracture pressure prediction model. The model can accurately predict and consider the target layer fracture pressure of anisotropy, and provides basis for reasonably determining a well structure, safely drilling, determining the fracturing construction pressure and the like.
EXAMPLE III
The method of establishing an anisotropic burst pressure prediction model based on an isotropic Huangronzun model is described in an embodiment.
First, the expression of the Huangrong goblet model for predicting burst pressure is:
wherein, PpIs the pore pressure of the target reservoir, k is the formation stress factor, SvOverburden pressure, S, for a target reservoirtAnd upsilon represents the Poisson ratio as the tensile strength of the target reservoir.
The isotropic assumption of the Huangronzun rupture pressure prediction model is reflected in Poisson ratio upsilon. The elastic stiffness matrix used to describe the isotropy of the rock is:
the elements in the elastic stiffness matrix used to describe the isotropy of the rock are expressed in terms of Lame parameters as follows:
wherein the content of the first and second substances,
thus, in Huangrong goblet model
This equation of connection is generalized to the elastic stiffness matrix used to describe the rock anisotropy. The elastic stiffness matrix for describing the rock anisotropy may be, for example, an orthorhombic crystal anisotropic elastic stiffness matrix:
of course, other forms of anisotropic (e.g., transverse anisotropy) stiffness matrices may be used to arrive at the same conclusion. Since orthorhombic crystal anisotropy is basically sufficient to describe the anisotropic properties in real rocks, we here use the elastic stiffness matrix of orthorhombic crystal anisotropy. Therefore, can be used in Huangrong goblet model
Is replaced by
Thus, the expression for the anisotropic burst pressure prediction model may be:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
Thus, a predictive model of the anisotropic burst pressure is established.
Predicting C in model for anisotropic fracture pressure13And C33The method can be obtained by direct calculation in a well in which the anisotropy measurement is carried out, and can be obtained by modeling an anisotropic rock physical model in a well in which the anisotropy measurement is not carried out.
The method of obtaining C13 and C33 by anisotropic rock physics modeling is illustrated below as Backus average for wells that have not undergone anisotropic measurements.
The well log interpretation results (mineral composition, porosity, saturation) are combined into a plurality of single layer isotropic elastic media based on anisotropic characteristics of the rock in the region of interest. The number of the independent elastic parameters of each single layer is 2, and the independent elastic parameters can be obtained by a theoretical estimation method of the equivalent modulus of the porous elastic material mixture, such as a self-consistent model, a differential equivalent medium model and the like, and the elastic rigidity matrix of each layer is expressed as follows:
where a ═ λ +2 μ, f ═ λ, and d ═ μ. At the long-wave limit, a layered medium composed of multiple layers of isotropic materials, the equivalent medium of which is transversely isotropic, and the equivalent stiffness can be expressed as:
wherein the content of the first and second substances,
A＝<a-f2c-1>+<c-1>-1<fc-1>2
B＝<b-f2c-1>+<c-1>-1<fc-1>2
C＝<c-1>-1
F＝<c-1>-1<fc-1>
D＝<d-1>-1
in the above formula, the brackets<>A weighted average of the bracketed attributes by volume ratio is shown. Thereby obtaining C13And C33：C13＝F，C33＝C。
Example four
The embodiment provides a method for preventing stratum from being fractured during drilling, which comprises the following steps:
the first step, predicting the anisotropic fracture pressure of the target reservoir according to the method for predicting the anisotropic fracture pressure in the first embodiment;
secondly, determining the fracture pressure coefficient of the target reservoir according to the anisotropic fracture pressure of the target reservoir;
thirdly, determining the maximum mud density of the injected mud during drilling according to the corresponding relation between the fracture pressure coefficient of the target reservoir and the maximum mud density;
and fourthly, controlling the density of the injected mud not to exceed the maximum mud density when drilling so as to prevent the stratum from cracking.
As shown in fig. 1, the method for predicting the anisotropic rupture pressure includes the following steps:
s100: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model;
s200: determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
s300: determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
s400: determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
s500: and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
Specifically, the expression of the anisotropic fracture pressure prediction model is as follows:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
Specifically, the anisotropic fracture pressure prediction model can be established by the following method:
first, the expression of the Huangrong goblet model for predicting burst pressure is:
wherein, PpIs the pore pressure of the target reservoir, k is the formation stress factor, SvOverburden pressure, S, for a target reservoirtAnd upsilon represents the Poisson ratio as the tensile strength of the target reservoir.
The isotropic assumption of the Huangronzun rupture pressure prediction model is reflected in Poisson ratio upsilon. The elastic stiffness matrix used to describe the isotropy of the rock is:
the elements in the elastic stiffness matrix used to describe the isotropy of the rock are expressed in terms of Lame parameters as follows:
wherein the content of the first and second substances,
thus, in Huangrong goblet model
This equation of connection is generalized to the elastic stiffness matrix used to describe the rock anisotropy. The elastic stiffness matrix for describing the rock anisotropy may be, for example, an orthorhombic crystal anisotropic elastic stiffness matrix:
of course, other forms of anisotropic (e.g., transverse anisotropy) stiffness matrices may be used to arrive at the same conclusion. Since orthorhombic crystal anisotropy is basically sufficient to describe the anisotropic properties in real rocks, we here use the elastic stiffness matrix of orthorhombic crystal anisotropy. Therefore, can be used in Huangrong goblet model
Is replaced by
Thus, the expression for the anisotropic burst pressure prediction model may be:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvIs the overburden of a target reservoirFormation pressure, StThe tensile strength of the target reservoir.
Thus, a predictive model of the anisotropic burst pressure is established.
Predicting C in model for anisotropic fracture pressure13And C33The method can be obtained by direct calculation in a well in which the anisotropy measurement is carried out, and can be obtained by modeling an anisotropic rock physical model in a well in which the anisotropy measurement is not carried out.
The method of obtaining C13 and C33 by anisotropic rock physics modeling is illustrated below as Backus average for wells that have not undergone anisotropic measurements.
The well log interpretation results (mineral composition, porosity, saturation) are combined into a plurality of single layer isotropic elastic media based on anisotropic characteristics of the rock in the region of interest. The number of the independent elastic parameters of each single layer is 2, and the independent elastic parameters can be obtained by a theoretical estimation method of the equivalent modulus of the porous elastic material mixture, such as a self-consistent model, a differential equivalent medium model and the like, and the elastic rigidity matrix of each layer is expressed as follows:
where a ═ λ +2 μ, f ═ λ, and d ═ μ. At the long-wave limit, a layered medium composed of multiple layers of isotropic materials, the equivalent medium of which is transversely isotropic, and the equivalent stiffness can be expressed as:
wherein the content of the first and second substances,
A＝<a-f2c-1>+<c-1>-1<fc-1>2
B＝<b-f2c-1>+<c-1>-1<fc-1>2
C＝<c-1>-1
F＝<c-1>-1<fc-1>
D＝<d-1>-1
in the above formula, the brackets<>A weighted average of the bracketed attributes by volume ratio is shown. Thereby obtaining C13And C33：C13＝F，C33＝C。
Specifically, determining overburden pressure of a target reservoir includes:
determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
Specifically, determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir comprises the following steps:
determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively, the effective stress and the seismic velocity of the target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress.
Specifically, determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir comprises the following steps: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir and σ is the effective stress of the target reservoir.
Specifically, determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir comprises the following steps:
determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
the method comprises the following steps of A, obtaining a reservoir stratum, wherein UCS is the uniaxial compressive strength of the target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is the empirical coefficient for the tensile strength of the target reservoir.
Determining a fracture pressure coefficient from the anisotropic fracture pressure of the target reservoir may include: the ratio of the anisotropic fracture pressure to the hydrostatic pressure of the target reservoir is determined as the fracture pressure coefficient.
And determining the maximum mud density during drilling according to the rupture pressure and the rupture pressure coefficient of the target reservoir layer considering anisotropy, and controlling the density of the injected mud not to exceed the maximum mud density in the drilling process so as to prevent stratum rupture in the drilling process and ensure the stability of the well wall.
In an anisotropic stratum, the stratum fracture pressure can be more accurately represented by considering the anisotropic fracture pressure, the prediction precision of the fracture pressure is improved, correct guidance is provided for selecting the mud density, the stability of a well wall in the drilling process is further ensured, and drilling accidents are prevented.
EXAMPLE five
This example is used to verify the advancement of the proposed method for predicting anisotropic burst pressure.
For a certain well, the stratum fracture pressure of the well is predicted by using the anisotropic fracture pressure prediction method and the Huangrong goblet model respectively.
As shown in fig. 1, the step of predicting the anisotropic fracture pressure of the well using the anisotropic fracture pressure prediction method of the present application may include:
s100: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model;
s200: determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
s300: determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
s400: determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
s500: and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
Specifically, the expression of the anisotropic fracture pressure prediction model is as follows:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
Specifically, determining overburden pressure of a target reservoir includes:
determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
Specifically, determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir comprises the following steps:
determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively, the effective stress and the seismic velocity of the target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress.
Specifically, determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir comprises the following steps: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir and σ is the effective stress of the target reservoir.
Specifically, determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir comprises the following steps:
determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
the method comprises the following steps of A, obtaining a reservoir stratum, wherein UCS is the uniaxial compressive strength of the target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is the empirical coefficient for the tensile strength of the target reservoir.
The step of predicting the fracture pressure of the well using the Huangrong goblet model may be performed by substituting the above parameters into the Huangrong goblet model to obtain the formation fracture pressure of the well.
Fig. 2 shows the results of predicting the fracture pressure using the anisotropic fracture pressure prediction method of the present application and the Huangronzun model for a well.
As shown in FIG. 2, the two prediction models predict that the trends of the rupture pressure have obvious difference, and the rupture pressure predicted by the anisotropic rupture pressure prediction method of the application is obviously increased in the high-quality shale section relative to the non-high-quality section.
EXAMPLE six
Fig. 3 is a schematic structural diagram of an anisotropic burst pressure prediction apparatus according to an exemplary embodiment of the present application. As shown in fig. 3, the present embodiment provides an anisotropic burst pressure predicting apparatus 10, including:
the model establishing module 101 is used for establishing an anisotropic fracture pressure prediction model of a target reservoir based on a Huangrong goblet model according to an elastic stiffness matrix describing rock anisotropy;
the overburden pressure determining module 102 is used for determining the overburden pressure of the target reservoir according to the change situation of the density of the target reservoir along with the depth;
the pore pressure determining module 103 is used for determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir based on the Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
the tensile strength determining module 104 is used for determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
and the fracture pressure determination module 105 is used for determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the rock anisotropy, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
In this embodiment, the anisotropic burst pressure prediction apparatus 10 may further include: a processor and a memory, wherein the processor is configured to execute the following program modules stored in the memory: a model building module 101, an overburden pressure determination module 102, a pore pressure determination module 103, a tensile strength determination module 104 and a fracture pressure determination module 105 to accurately predict fracture pressure under consideration of rock anisotropy.
The specific embodiment of the method for predicting the anisotropic burst pressure performed based on the modules is described in detail in the first to third embodiments, and will not be described herein again.
EXAMPLE seven
The present embodiment provides a storage medium storing a computer program, which when executed by a processor, implements the following method steps:
s100: establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model;
s200: determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
s300: determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
s400: determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
s500: and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
Optionally, the expression of the anisotropic fracture pressure prediction model is as follows:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvOverburden pressure, S, for a target reservoirtThe tensile strength of the target reservoir.
Optionally, determining overburden pressure of the target reservoir includes:
determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
Optionally, determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir includes:
determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively, the effective stress and the seismic velocity of the target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress.
Optionally, determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir includes: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir and σ is the effective stress of the target reservoir.
Optionally, determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, including:
determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
the method comprises the following steps of A, obtaining a reservoir stratum, wherein UCS is the uniaxial compressive strength of the target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is the empirical coefficient for the tensile strength of the target reservoir.
Or the steps of a method of preventing formation fracture while drilling:
a first step of predicting the anisotropic fracture pressure of the target reservoir according to the anisotropic fracture pressure prediction method described above;
secondly, determining the fracture pressure coefficient of the target reservoir according to the anisotropic fracture pressure of the target reservoir;
thirdly, determining the maximum mud density of the injected mud during drilling according to the corresponding relation between the fracture pressure coefficient of the target reservoir and the maximum mud density;
and fourthly, controlling the density of the injected mud not to exceed the maximum mud density when drilling so as to prevent the stratum from cracking.
Optionally, determining a fracture pressure coefficient according to the anisotropic fracture pressure of the target reservoir includes: the ratio of the anisotropic fracture pressure to the hydrostatic pressure of the target reservoir is determined as the fracture pressure coefficient.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method or computer program product. Accordingly, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations of methods and computer program products according to embodiments of the invention. It will be understood that each flow of the flowcharts, and combinations of flows in the flowcharts, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows.
Storage media, including permanent and non-permanent, removable and non-removable media, may implement the information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.
Example eight
The present embodiments provide a computer device comprising a processor and a storage medium having stored thereon program code which, when executed by the processor, implements the steps of the method of predicting anisotropic fracture pressure as described above or the method of preventing formation fractures while drilling as described above.
In one embodiment, a computer device includes one or more processors (CPUs), input/output interfaces, a network interface, and memory.
The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or FLASH memory (FLASH RAM). Memory is an example of a computer-readable medium.
The method and system of the present disclosure may be implemented in a number of ways. For example, the methods and systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless specifically stated otherwise. Further, in some embodiments, the present disclosure may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.
It is noted that the terms used herein are merely for describing particular embodiments and are not intended to limit exemplary embodiments according to the present application, and when the terms "include" and/or "comprise" are used in this specification, they specify the presence of features, steps, operations, devices, components, and/or combinations thereof.
It should be understood that the exemplary embodiments herein may be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art, and should not be construed as limiting the present invention.
Claims (11)
1. A method for predicting anisotropic burst pressure, comprising the steps of:
establishing an anisotropic fracture pressure prediction model of a target reservoir according to an elastic stiffness matrix describing the anisotropy of the rock based on a Huangrong model;
determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
determining the effective stress of a target reservoir according to the compressional wave velocity of the target reservoir based on an Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir, and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
and determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
2. The method of predicting anisotropic burst pressure of claim 1, wherein the expression of the anisotropic burst pressure prediction model is:
wherein, PfIndicating the anisotropic fracture pressure, P, of the rockpPore pressure, C, representing the target reservoir13And C33The element of the elastic stiffness matrix to describe the anisotropy of the rock, k being the formation stress coefficient, SvIs the upper part of a target reservoirOverburden pressure, StThe tensile strength of the target reservoir.
3. The method of claim 1, wherein determining overburden pressure of the target reservoir comprises:
determining overburden pressure for the target reservoir using the formula:
wherein S isv(H) The overburden pressure of a target reservoir is shown, H is the depth of the target reservoir, rho (z) is the density value of the target reservoir with the depth of z along the drilling direction, and g is the gravity acceleration.
4. The method for predicting anisotropic fracture pressure according to claim 1, wherein determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir comprises:
determining the effective stress of the target reservoir using the formula:
σ＝σnormal(V/Vnormal)n
wherein, sigma is the effective stress of the target reservoir, V is the longitudinal wave velocity of the target reservoir, and sigmanormalAnd VnormalRespectively, the effective stress and the seismic velocity of the target reservoir during normal compaction, and n is a parameter describing the sensitivity of the velocity to the effective stress.
5. The method of claim 4, wherein determining the pore pressure of the target reservoir based on the overburden pressure and the effective stress of the target reservoir comprises: determining the pore pressure of the target reservoir using the formula:
Pp＝Sv-σ
wherein, PpPore pressure, S, representing the target reservoirvIs the overburden pressure of the target reservoir, and σ is the target reservoirEffective stress of the layer.
6. The method for predicting anisotropic fracture pressure according to claim 1, wherein determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir comprises:
determining the uniaxial compressive strength of the target reservoir using the formula:
UCS＝a*E*(1-Vsh)+b*E*Vsh
the method comprises the following steps of A, obtaining a reservoir stratum, wherein UCS is the uniaxial compressive strength of the target reservoir stratum, E is the Young modulus, Vsh is the shale content of the target reservoir stratum, and a and b are empirical coefficients;
determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir, comprising: determining the tensile strength of the target reservoir using the formula:
St＝UCS/c
wherein S istC is the empirical coefficient for the tensile strength of the target reservoir.
7. A method of preventing formation fracturing while drilling, comprising the steps of:
the method for predicting anisotropic fracture pressure according to any one of claims 1 to 6, predicting anisotropic fracture pressure of a target reservoir;
determining a fracture pressure coefficient of the target reservoir according to the anisotropic fracture pressure of the target reservoir;
determining the maximum mud density of the injected mud during drilling according to the corresponding relation between the fracture pressure coefficient of the target reservoir and the maximum mud density;
the density of the injected mud is controlled to not exceed the maximum mud density while drilling to prevent formation fracture.
8. The method of preventing formation fractures while drilling according to claim 7, wherein determining a fracture pressure coefficient from the target reservoir's anisotropic fracture pressure comprises:
the ratio of the anisotropic fracture pressure to the hydrostatic pressure of the target reservoir is determined as the fracture pressure coefficient.
9. A storage medium storing a computer program, wherein the computer program, when executed by a processor, performs the steps of the method for predicting an anisotropic fracture pressure according to any of claims 1-6 or the method for preventing formation fractures while drilling according to claim 7 or 8.
10. A computer device comprising a processor and a storage medium storing program code which, when executed by the processor, carries out the steps of the method of predicting anisotropic fracture pressure according to any of claims 1-6 or the method of preventing formation fractures while drilling according to claim 7 or 8.
11. An apparatus for predicting an anisotropic fracture pressure, comprising:
the model establishing module is used for establishing an anisotropic fracture pressure prediction model of the target reservoir based on the Huangronzun model according to the elastic stiffness matrix describing the anisotropy of the rock;
the overburden pressure determining module is used for determining the overburden pressure of the target reservoir according to the change condition of the density of the target reservoir along with the depth;
the pore pressure determining module is used for determining the effective stress of the target reservoir according to the compressional wave velocity of the target reservoir based on the Eaton method, and determining the pore pressure of the target reservoir according to the overburden pressure and the effective stress of the target reservoir;
the tensile strength determining module is used for determining the uniaxial compressive strength of the target reservoir according to the shale content of the target reservoir and determining the tensile strength of the target reservoir according to the uniaxial compressive strength of the target reservoir;
and the fracture pressure determining module is used for determining the anisotropic fracture pressure of the target reservoir according to the elastic stiffness matrix describing the anisotropy of the rock, the overburden pressure, the pore pressure and the tensile strength based on the anisotropic fracture pressure prediction model.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080086287A1 (en) * | 2004-12-06 | 2008-04-10 | Shiyu Xu | Integrated Anisotropic Rock Physics Model |
| CN103206206A (en) * | 2012-01-16 | 2013-07-17 | 中国石油化工股份有限公司 | Method for calculating fracture pressure of ultra deep well formations |
| CN103792581A (en) * | 2013-12-31 | 2014-05-14 | 刘致水 | Shale gas reservoir crustal stress logging prediction method based on rock physics model |
| US20150055438A1 (en) * | 2013-08-24 | 2015-02-26 | Schlumberger Technology Corporation | Formation stability modeling |
| US20170321531A1 (en) * | 2014-12-17 | 2017-11-09 | Halliburton Energy Services, Inc. | Geomechanical model of stresses on an orthorhombic media |
| CN108089227A (en) * | 2017-12-12 | 2018-05-29 | 中国石油天然气集团有限公司 | The new formation pore pressure Forecasting Methodology based on three dimensional seismic data |
| CN108952700A (en) * | 2018-08-21 | 2018-12-07 | 西南石油大学 | A kind of anisotropic formation shaft wall fracture pressure determination statement |
| CN111159917A (en) * | 2020-01-06 | 2020-05-15 | 中国石油化工股份有限公司 | Rock physical model-based anisotropic fluid factor construction method |
-
2020
- 2020-07-22 CN CN202010712305.0A patent/CN113969782A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080086287A1 (en) * | 2004-12-06 | 2008-04-10 | Shiyu Xu | Integrated Anisotropic Rock Physics Model |
| CN103206206A (en) * | 2012-01-16 | 2013-07-17 | 中国石油化工股份有限公司 | Method for calculating fracture pressure of ultra deep well formations |
| US20150055438A1 (en) * | 2013-08-24 | 2015-02-26 | Schlumberger Technology Corporation | Formation stability modeling |
| CN103792581A (en) * | 2013-12-31 | 2014-05-14 | 刘致水 | Shale gas reservoir crustal stress logging prediction method based on rock physics model |
| US20170321531A1 (en) * | 2014-12-17 | 2017-11-09 | Halliburton Energy Services, Inc. | Geomechanical model of stresses on an orthorhombic media |
| CN108089227A (en) * | 2017-12-12 | 2018-05-29 | 中国石油天然气集团有限公司 | The new formation pore pressure Forecasting Methodology based on three dimensional seismic data |
| CN108952700A (en) * | 2018-08-21 | 2018-12-07 | 西南石油大学 | A kind of anisotropic formation shaft wall fracture pressure determination statement |
| CN111159917A (en) * | 2020-01-06 | 2020-05-15 | 中国石油化工股份有限公司 | Rock physical model-based anisotropic fluid factor construction method |
Non-Patent Citations (2)
| Title |
|---|
| 马妮，林正良，胡华锋，周单，王世星: "页岩地层的破裂压力地震预测方法", 石油物探, vol. 58, no. 6, 25 November 2019 (2019-11-25), pages 926 - 934 * |
| 黄荣樽: "地层破裂压力预测模式的探讨", 石油大学学报(自然科学版), no. 04, 5 August 1984 (1984-08-05), pages 16 - 28 * |
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