CN112100941A - High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method - Google Patents

High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method Download PDF

Info

Publication number
CN112100941A
CN112100941A CN202010985111.8A CN202010985111A CN112100941A CN 112100941 A CN112100941 A CN 112100941A CN 202010985111 A CN202010985111 A CN 202010985111A CN 112100941 A CN112100941 A CN 112100941A
Authority
CN
China
Prior art keywords
fracture
fluid
thermo
solid coupling
cavity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010985111.8A
Other languages
Chinese (zh)
Inventor
姚军
张旭
黄朝琴
巩亮
刘文政
杨文东
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China University of Petroleum East China
Original Assignee
China University of Petroleum East China
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China University of Petroleum East China filed Critical China University of Petroleum East China
Priority to CN202010985111.8A priority Critical patent/CN112100941A/en
Publication of CN112100941A publication Critical patent/CN112100941A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/18—Network design, e.g. design based on topological or interconnect aspects of utility systems, piping, heating ventilation air conditioning [HVAC] or cabling
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
    • G06F2111/10—Numerical modelling
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/08—Fluids
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Evolutionary Computation (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Pure & Applied Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mathematical Physics (AREA)
  • Computing Systems (AREA)
  • Algebra (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Computational Mathematics (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)

Abstract

The invention discloses a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method, which comprises the following steps of: acquiring the geometric information of cracks and karst caves of a high-temperature fracture-cave reservoir stratum, and generating a discrete fracture-cave model meeting fractal and power law distribution; establishing a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling mathematical model and a numerical calculation method, and carrying out thermo-fluid-solid coupling numerical simulation on a discrete fracture-cavity model meeting fractal power law distribution. The method provided by the invention can better simulate the energy and quality transmission rule of the high-temperature fracture-cavity reservoir under the comprehensive consideration of the geometrical property of a discrete fracture-cavity network and the thermo-fluid-solid coupling effects such as seepage-free flow coupling, local non-thermal equilibrium effect, fracture nonlinear shear-expansion deformation and the like, is suitable for practical application, predicts the development dynamics of the high-temperature fracture-cavity reservoir and determines the main factors influencing the development dynamics of the high-temperature fracture-cavity reservoir.

Description

High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method
Technical Field
The invention relates to the field of geothermal field numerical simulation, in particular to a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method.
Background
Aiming at potential energy crisis and environmental problems, renewable energy geothermal resources which are huge in resource consumption, strong in sustainability and environment-friendly are used as solutions for replacing fossil energy. The high-temperature fracture-cave carbonate reservoir consists of a bedrock system, a fracture system and a karst cave system, and belongs to one of geothermal resources. Due to tectonic movement and the erosion effect of the paleo-karst, well-developed cracks (distributed in a disconnected or connected mode) and caverns (isolated or connected with the cracks and with diameters ranging from centimeters to meters) have obvious multi-scale property.
The heat transfer process of the fracture-cavity reservoir is mainly controlled by fluid flow, and natural fractures and karst caves of the fracture-cavity reservoir are complex in geometric shapes and are main channels for fluid flow of underground rock masses. The fluid flow capacity mainly depends on the connectivity of a fracture-cavity network and the flow conductivity of fracture-cavity units, the connectivity of the fracture-cavity network is controlled by the geometric distribution of the fracture-cavity, and the flow conductivity of the fracture-cavity units, particularly the fracture units, is influenced by geomechanical action. The geometrical complexity of the fracture-cavity network is represented through the size, density, trend, opening and distribution of the fracture-cavity, and a discrete fracture-cavity system generated based on the random and statistical properties met by the characteristic parameters of the fracture-cavity network can well represent the natural fracture-cavity network and research the influence of uncertainty on the flow heat transfer of a high-temperature reservoir. Under the circulation action of cold fluid in a reservoir, the balance of a pressure field, a temperature field and a stress field of a high-temperature reservoir is damaged, and in addition, strong local stress disturbance can be generated due to the existence of a fracture-cavity network, so that variable tangential and normal stresses are generated on fracture surfaces with different sizes and trends, and different fracture stress responses are caused, including opening, closing, sliding and shear-swelling processes. And the flow conductivity of the crack depends on the opening of the crack, so the energy and mass transmission of the porous medium of the crack can be seriously influenced by the thermo-hydro-solid coupling process. Therefore, in order to develop a high-temperature fracture-cavity reservoir efficiently, it is necessary to comprehensively consider the geometric attributes of the fracture-cavity network and the thermo-fluid-solid coupling effect and establish an accurate thermo-fluid-solid coupling numerical simulation method and technology.
Disclosure of Invention
The invention aims to provide a method and a technology for numerical simulation of a high-temperature fracture-cavity reservoir, which are used for establishing a thermal fluid-solid coupling numerical simulation method based on a discrete fracture-cavity network model by considering the geometric attributes of the discrete fracture-cavity network, seepage-free flow coupling, local non-thermal equilibrium effect and fracture nonlinear shear-swelling deformation so as to disclose the energy and mass transmission mechanism of the high-temperature fracture-cavity reservoir.
To achieve the above object, the present invention provides the following method:
a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method is characterized by comprising the following steps:
s1, acquiring geometric information of the high-temperature fracture-cave reservoir fracture and the karst cave, and determining the power law length index and fractal dimension of the fracture and the karst cave;
step S2, establishing a discrete slot network model according to the power law length index and the fractal dimension;
s3, establishing a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling mathematical model and a thermo-fluid-solid coupling model calculation method;
and step S4, carrying out thermal fluid solid coupling numerical simulation on the discrete slot hole model according to the mathematical model and the thermal fluid solid coupling model calculation method.
Preferably, the step S2 includes the steps of:
s2.1, determining the length distribution of the fracture karst cave: selecting a size change increment of the fracture and cave within the size range of the fracture and cave, and determining the length of the fracture and the karst cave and the number of the corresponding fracture and cave within the size increment range according to the power law length index;
s2.2, determining the distribution of the central points of the slots: generating a slot center with fractal space density distribution based on a multiplication cascade process;
s2.3, generating a discrete fracture model and a discrete karst cave model meeting the acquired geometric information of the fracture cave by a Monte Carlo method;
and S2.4, judging the intersection condition of the cracks and the karst caves, and generating a corrected crack karst cave network model.
Preferably, the increment of the size change of the slotted holes is the increment of the size change of the slotted holes in the size range of the slotted holes, and the total number of the increment of the size change of the slotted holes divided in the size range of the slotted holes is 20-30.
Preferably, the specific steps of the multiplication cascade process are: creating a cell containing N subregions, randomly distributing a probability to each subregion in the cell, then iterating to generate a fractal probability field following a multiplication cascade process, repeating the process to generate the fractal probability field after continuously iterating for N times, and determining the position of the central point of the slot-hole network according to the fractal probability field.
Preferably, the step S3 includes: establishing a stress field equation for considering the influence of fluid pressure and thermal stress; establishing a seepage field equation and a temperature field equation and constructing a thermo-fluid-solid coupling model; establishing a crack deformation equation for considering the influence of nonlinear crack closure and shear expansion effect on the opening; and establishing a total balance equation based on a small deformation assumption of the stress action deformation quantity and a quasi-static assumption that the thermo-hydro-solid coupling model is always in a mechanical balance state.
Preferably, the seepage field equation comprises: the method comprises the following steps of a matrix, cracks and cave internal flow mass conservation equation, a matrix and crack internal Darcy flow equation, a cave internal N-S flow equation and seepage and free flow region expansion BJS coupling boundary conditions.
Preferably, the temperature field equation comprises: the energy conservation equation in the matrix, the cracks and the karst caves and the local non-heat balance heat exchange equation at the interfaces of the matrix, the cracks and the karst caves.
Preferably, the step S4 includes:
s4.1, performing thermal fluid-solid coupling numerical simulation on the high-temperature fracture-cavity reservoir based on the thermal fluid-solid attribute parameters of the high-temperature fracture-cavity reservoir by combining a discrete fracture-cavity model, a high-temperature fracture-cavity reservoir thermal fluid-solid coupling mathematical model and a method for calculating a thermal fluid-solid coupling model;
and S4.2, outputting a thermo-fluid-solid coupling numerical simulation result, wherein the thermo-fluid-solid coupling numerical simulation result comprises reservoir temperature, pressure, stress, fracture opening distribution, outlet flow and a temperature curve.
Preferably, the high-temperature fracture-cavity reservoir and fluid property parameters include: matrix and fracture porosity, permeability, specific heat capacity, heat conduction coefficient, water storage coefficient, heat exchange coefficient, Young modulus of the matrix, Poisson's ratio, initial opening degree of the fracture, shear/normal stiffness, static/dynamic friction coefficient, cohesion, maximum fracture closure, expansion angle and reservoir fluid physical property parameters.
The invention has the following technical effects:
1. the method can actually represent the discrete fracture-cavity network geometric model, systematically study the influence of the geometric attributes of the discrete fracture-cavity network model on the energy and mass transmission process of the high-temperature fracture-cavity reservoir and determine the influence degree, and is suitable for practical application;
2. the method can simulate the influence of the thermo-hydro-solid coupling effect of the high-temperature fracture-cavity reservoir on the energy and mass transmission process of the high-temperature fracture-cavity reservoir and determine the influence degree;
3. the method can comprehensively research the influence of the geometric connectivity and the thermo-hydro-solid coupling effect of the fracture-cavity network on the energy and mass transmission process of the high-temperature fracture-cavity reservoir and determine main control influence factors.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below.
FIG. 1 is a schematic diagram of the steps of the numerical simulation method of the high-temperature fracture-cavity reservoir according to the present invention;
FIG. 2 is a schematic diagram illustrating a process of determining fracture-cavern center point fractal distribution based on a multiplication cascade process according to the present invention;
FIG. 3 is a schematic diagram of a geometric model of a discrete fracture network according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a geometric model of a discrete karst cave network according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a geometric model of a discrete slot-and-hole network according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating an iterative solution of the thermo-fluid-solid coupling model according to the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. But the embodiments of the present invention are not limited thereto.
As shown in fig. 1, the invention provides a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method, which comprises the following specific steps:
and S1, acquiring the high-temperature fracture-cavity reservoir fracture and karst cave geometric information.
S1.1, acquiring the geometrical information of the fractures and the karst caves of the high-temperature fracture-cavity reservoir according to the actual geological data or the existing geological model data of the high-temperature fracture-cavity reservoir: the fracture geometric information comprises fracture position, size, density, trend and opening degree; the karst cave geometric information comprises the shape, position, size, density and trend of the karst cave;
s1.2, according to the geometrical information of the cracks and the karst caves, carrying out interval division on the sizes of the cracks and the karst caves, determining the number N (l) of the cracks and the karst caves in each size interval [ l, l + dl ], and determining a power law length index a through a frequency distribution function N (l);
N(l)＝αl-adl (1)
wherein l is the size of the crack or the karst cave, dl is the change increment of the size of the crack or the karst cave (dl < < l), alpha is a density constant, and a is a power law length index.
S1.3, determining the fractal dimension D of the crack and the karst cave by a box counting method according to the information of the position, the size, the trend and the like of the crack and the karst cave; the box counting method is to divide a model area by a square box with the side length r, determine the total number N (r) of the centers of cracks or karsts in the small square box, and specifically comprises the following steps:
Figure BDA0002688965560000061
and S2, generating a discrete slot and hole network model meeting fractal slot and hole center distribution and power law slot and hole length distribution according to the slot and hole network geometric information.
S2.1, determining the length distribution of the fracture karst cave: and selecting a proper change increment of the size of the slot in the size range of the slot, and determining the number of the slots and the karst caves in the range of the lengths [ l, l + dl ] according to the frequency distribution function N (l) and the power law index a obtained in the step S1.
S2.2, determining the distribution of the central points of the fracture karst caves: and generating a slot center with fractal space density distribution based on a multiplication cascade process. The multiplication cascade process generates point fractal distribution through iteration and multiplication random process. The method comprises the following specific steps: creating a cell comprising n subregions and randomly assigning a probability p to each subregion in the celli}i＝1,2…n，pi∈[0,1]As shown in fig. 2(a), (n ═ 4). Secondly, iterating to generate a fractal probability field following a multiplication cascade process, for example, subdividing each subregion into n equal subregions through a first iteration process to obtain a fractal probability field containing n2Sub-region cells, each new sub-region being re-randomly assigned a probability pi}i＝1,2…nThe probability of the sub-region is the same probability as the probability, and the probability of the sub-region is the newly allocated probability multiplied by the probability of the parent domain, as shown in fig. 2 (b); by analogy, a fractal probability field after continuous iteration for N times can be generated. Finally, the position of the central point of the slot-hole network is determined according to the fractal probability field, as shown in fig. 2(c), where the iteration number N is 6. Satisfy fractal dimension Dq and probability { p of final probability fieldi}i＝1,2…nSatisfies the relation:
Figure BDA0002688965560000071
where l is the ratio of the parent domain size to each child domain size.
When q is 1, probability set { pi}i＝1,2…nThe sum of the elements is equal to 1.
And S2.3, generating a discrete fracture model and a discrete karst cave model meeting the acquired geometric information of the fracture cave by a Monte Carlo method. The discrete fracture model and the discrete cave model obtained in this example are shown in fig. 3 and 4, respectively.
S2.4, judging the intersection condition of the cracks and the karst caves, wherein the generated new model is a corrected crack karst cave network model: and circulating all cracks and karst caves, reading the geometric information of the cracks and the karst caves, judging whether the cracks and the karst caves are intersected and the position relation between the crack segmented sections by the karst caves and the karst caves, and deleting the crack karst cave network model if the cracks are judged to be in the karst caves. And obtaining a corrected crack karst cave network model according to the corrected crack karst cave. The fracture and cave network model obtained by the embodiment of the invention is specifically shown in fig. 5.
S3, establishing high-temperature fracture-cavity reservoir thermo-fluid-solid coupling mathematical model and numerical calculation method
S3.1, establishing a stress field equation: considering the influence of fluid pressure and thermal stress, establishing an effective stress equation; considering the influence of nonlinear crack closure and shear expansion effect on the opening; and establishing a total balance equation based on the small deformation with the stress action deformation quantity far smaller than the size of the original model and the quasi-static assumption that the thermo-hydro-solid coupling model is always in a mechanical balance state. The stress field equation includes: the method comprises the following steps of (1) a total balance equation, a crack opening deformation equation, a crack normal nonlinear deformation equation and a crack tangential shear expansion equation:
the overall equilibrium equation:
▽·σp+ρeffg＝0
σ'＝σp+(αBpp+K'αTTs)I (4)
σp＝C:s
where σ' and σpTotal stress tensor and effective stress tensor, ρeff＝(1-)ρs+ρfEffective density of porous media determined by volume average, ρ density "s "and" f "denote solid and fluid, respectively, as the porosity of the matrix, alphaBAs coefficient of Biot, ppIs the porous medium pressure, I is the unit tensor, C is the fourth order elastic tensor,
Figure BDA0002688965560000081
is the strain tensor, usIs the solid displacement;
fracture opening deformation equation:
df＝df0+vs+vn (5)
wherein d isfoIs the initial crack opening, vnNormal deformation caused by normal stress, vsThe shear expansion caused by shear displacement;
fracture normal nonlinear deformation equation:
Figure BDA0002688965560000082
wherein sigma'n＝σn-αBppEffective normal stress, Kn0Initial normal stress stiffness, vmMaximum fracture closure;
fracture tangential shear swell equation:
Figure BDA0002688965560000091
Figure BDA0002688965560000092
wherein tau issFor shear stress, τRShear strength, c cohesion, psi Friction Angle, mu Friction coefficient, usFor shear displacement, upIn order to obtain the peak shear displacement,
Figure BDA0002688965560000093
angle of expansion, KsCrack tangential stiffness.
S3.2, establishing a seepage field equation: the fluid seepage system consists of a bedrock seepage system, a fracture seepage system and a karst cave seepage system, wherein the bedrock and the fracture system are seepage areas, the flow meets Darcy' S law, the influence of a thermo-hydro-solid coupling seepage mechanism is considered, the relation between the fracture permeability and the fracture opening degree in the fracture system meets cubic law, the karst cave system is a free flow area, and the flow adopts an N-S equation; and the two regions are coupled by adopting an extended BJS condition. The seepage field equation includes: the method comprises the following steps of (1) a conservation equation of flow quality in a matrix, a crack and a karst cave, a Darcy flow equation in the matrix and the crack, an N-S flow equation in the karst cave and an expansion BJS coupling boundary condition of a seepage and free flow region, wherein the method specifically comprises the following steps:
mass conservation equation in the matrix:
Figure BDA0002688965560000094
wherein S is the water storage coefficient of the porous medium, t is time, vpFlow velocity in the matrix, e volume strain, and Q source-sink term;
the conservation of mass equation in the fracture:
Figure BDA0002688965560000101
wherein d isfIs the opening of the fracture, SfWater storage coefficient for cracks, vfFlow velocity in the fracture, efFracture volume strain, QfIs a source and sink item;
mass conservation equation in karst cave:
Figure BDA0002688965560000102
wherein u isfIs the free flow region fluid velocity;
intrastromal darcy flow equation:
Figure BDA0002688965560000103
wherein k is the matrix permeability, μ is the hydrodynamic viscosity, and g is the acceleration of gravity;
darcy flow equation in fracture:
Figure BDA0002688965560000104
wherein
Figure BDA0002688965560000105
The gradient operator along the tangential direction of the fracture,
Figure BDA0002688965560000106
is the crack permeability;
N-S flow equation in the karst cave:
Figure BDA0002688965560000107
wherein sigmaf＝-pfI+2μfIn order to be the cauchy stress tensor,
Figure BDA0002688965560000108
to strain rate tensor, pfIs the fluid pressure in the karst cave;
seepage and free flow region extension BJS coupling boundary condition:
Figure RE-GDA0002741711550000111
wherein n and tau represent normal and tangential unit vectors of porous medium and karst cave interface, vpThe fluid velocity beta of the porous medium is the interfacial tangential resistance coefficient.
S3.3, establishing a temperature field equation: the energy transmission considers two modes of heat conduction and heat convection, considers the influence of rock deformation and fluid flow, establishes an energy conservation equation in the matrix, the cracks and the karst caves, and establishes a heat exchange equation among the matrix, the cracks and the karst caves according to a rock-fluid local non-heat balance theory. The temperature field equation includes: the energy conservation equation in the matrix, the cracks and the karst caves is as follows:
energy conservation equation in the matrix:
Figure BDA0002688965560000112
energy conservation equation in the crack:
Figure BDA0002688965560000113
energy conservation equation in karst cave:
Figure BDA0002688965560000114
wherein, (rho C)eff＝(1-)ρsCs+ρfCfAnd λeff＝(1-)λs+λfEffective specific heat and effective heat transfer coefficient based on volume average, T is temperature, v is fluid velocity, rho is density, C is specific heat capacity, lambda is heat transfer coefficient, matrix porosity, q isfIs a heat source sink, qf＝h(Ts-Tf) Based on Newtonian heat exchange formula, the local non-heat balance heat exchange quantity between the fracture fluid and the bedrock in unit area, h heat exchange coefficient and TvAnd (3) the temperature of fluid in the karst cave, wherein A is the interface area of the porous medium and the karst cave.
S3.4, constructing a heat-fluid-solid coupling model calculation method: as shown in fig. 6, the discrete slot hole thermo-hydro-solid coupling mathematical model is solved by using a finite element method. The matrix and the crack system adopt a standard Galerkin finite element method, the karst cave system adopts a Taylor-Hood mixed element method, and the crack adopts dimensionality reduction treatment. Carrying out full-implicit solution on the temperature field, the seepage field and the stress field by adopting a Newton iteration method; for the integral thermo-hydro-solid coupling model, the seepage field and the temperature field are solved simultaneously, then the stress field is solved according to the calculated pressure and temperature, relevant parameters in the model are updated according to the effective stress, and the seepage field and the temperature field are solved again until the stress field, the temperature field and the seepage field all meet the requirement of iterative solution Newton-Raphson.
And S4, performing the thermo-fluid-solid coupling numerical simulation on the discrete fracture-cave model meeting the fractal power law distribution.
S4.1, performing high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation based on reservoir and fluid property parameters including matrix and fracture porosity, permeability, specific heat capacity, heat conduction coefficient, water storage coefficient, heat exchange coefficient, Young modulus of the matrix, Poisson' S ratio, initial opening degree of the fracture, shear/normal stiffness, static/dynamic friction coefficient, cohesive force, maximum fracture closure amount, expansion angle and reservoir fluid physical property parameters by combining the discrete fracture-cavity model in the step S2, the mathematical model in the step S3 and a numerical calculation method;
and S4.2, outputting numerical simulation results including reservoir temperature, pressure, stress, fracture opening distribution, outlet flow and temperature curves.
The method can actually represent the discrete fracture-cavity network geometric model, systematically study the influence of the geometric attributes of the discrete fracture-cavity network model on the energy and mass transmission process of the high-temperature fracture-cavity type fracture reservoir and determine the influence degree. The influence of the thermo-fluid-solid coupling effect of the high-temperature fracture-cavity reservoir on the energy and mass transmission process of the high-temperature fracture-cavity reservoir can be simulated, and the influence degree of the thermo-fluid-solid coupling effect of the high-temperature fracture-cavity reservoir can be determined. The method can comprehensively research the influence of the geometric connectivity and the thermo-hydro-solid coupling effect of the fracture-cavity network on the energy and mass transmission process of the high-temperature fracture-cavity reservoir and determine main control influence factors.

Claims (9)

1. A high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method is characterized by comprising the following steps:
s1, acquiring geometric information of the high-temperature fracture-cave reservoir fracture and the karst cave, and determining the power law length index and fractal dimension of the fracture and the karst cave;
step S2, establishing a discrete slot network model according to the power law length index and the fractal dimension;
s3, establishing a high-temperature fracture-cavity reservoir thermo-fluid-solid coupling mathematical model and a thermo-fluid-solid coupling model calculation method;
and step S4, carrying out thermal fluid solid coupling numerical simulation on the discrete slot hole model according to the mathematical model and the thermal fluid solid coupling model calculation method.
2. The method for simulating the thermo-fluid-solid coupling numerical value of the high-temperature fracture-cavity reservoir according to claim 1, wherein the step S2 comprises the following steps:
s2.1, determining the length distribution of the fracture karst cave: selecting a size change increment of the fracture and cave within the size range of the fracture and cave, and determining the length of the fracture and the karst cave and the number of the corresponding fracture and cave within the size increment range according to the power law length index;
s2.2, determining the distribution of the central points of the slots: generating a slot center with fractal space density distribution based on a multiplication cascade process;
s2.3, generating a discrete fracture model and a discrete karst cave model meeting the acquired geometric information of the fracture cave by a Monte Carlo method;
and S2.4, judging the intersection condition of the cracks and the karst caves, and generating a corrected crack karst cave network model.
3. The high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method of claim 2, wherein the fracture-cavity size change increment is a fracture-cavity size change increment in a fracture-cavity size range, and the total number of the fracture-cavity size change increments divided in the fracture-cavity size range is 20-30.
4. The high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method of claim 2, wherein the multiplication cascade process comprises the following specific steps: creating a cell containing N subregions, randomly distributing a probability to each subregion in the cell, then iterating to generate a fractal probability field following a multiplication cascade process, repeating the process to generate the fractal probability field after continuously iterating for N times, and determining the position of the central point of the slot-hole network according to the fractal probability field.
5. The method for simulating the thermo-fluid-solid coupling numerical value of the high-temperature fracture-cavity reservoir according to claim 1, wherein the step S3 includes: establishing a stress field equation for considering the influence of fluid pressure and thermal stress; establishing a seepage field equation and a temperature field equation and constructing a thermo-fluid-solid coupling model; establishing a crack deformation equation for considering the influence of nonlinear crack closure and shear expansion effect on the opening; and establishing a total balance equation based on a small deformation assumption of the stress action deformation quantity and a quasi-static assumption that the thermo-hydro-solid coupling model is always in a mechanical balance state.
6. The method for simulating the thermo-fluid-solid coupling numerical value of the high-temperature fracture-cavity reservoir according to claim 5, wherein the seepage field equation comprises: the method comprises the following steps of a matrix, cracks and cave internal flow mass conservation equation, a matrix and crack internal Darcy flow equation, a cave internal N-S flow equation and seepage and free flow region expansion BJS coupling boundary conditions.
7. The high-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method of claim 5, wherein the temperature field equation comprises: the energy conservation equation in the matrix, the cracks and the karst caves and the local non-heat balance heat exchange equation at the interfaces of the matrix, the cracks and the karst caves.
8. The method for simulating the thermo-fluid-solid coupling numerical value of the high-temperature fracture-cavity reservoir according to claim 1, wherein the step S4 includes:
s4.1, performing thermal fluid-solid coupling numerical simulation on the high-temperature fracture-cavity reservoir based on the thermal fluid-solid attribute parameters of the high-temperature fracture-cavity reservoir by combining a discrete fracture-cavity model, a high-temperature fracture-cavity reservoir thermal fluid-solid coupling mathematical model and a method for calculating a thermal fluid-solid coupling model;
and S4.2, outputting a thermo-fluid-solid coupling numerical simulation result, wherein the thermo-fluid-solid coupling numerical simulation result comprises reservoir temperature, pressure, stress, fracture opening distribution, outlet flow and a temperature curve.
9. The method for simulating the thermo-fluid-solid coupling numerical value of the high-temperature fracture-cavity reservoir according to claim 8, wherein the high-temperature fracture-cavity reservoir and fluid property parameters comprise: matrix and fracture porosity, permeability, specific heat capacity, heat conduction coefficient, water storage coefficient, heat exchange coefficient, Young modulus of the matrix, Poisson's ratio, initial opening degree of the fracture, shear/normal stiffness, static/dynamic friction coefficient, cohesion, maximum fracture closure, expansion angle and reservoir fluid physical property parameters.
CN202010985111.8A 2020-09-18 2020-09-18 High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method Pending CN112100941A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010985111.8A CN112100941A (en) 2020-09-18 2020-09-18 High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010985111.8A CN112100941A (en) 2020-09-18 2020-09-18 High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method

Publications (1)

Publication Number Publication Date
CN112100941A true CN112100941A (en) 2020-12-18

Family

ID=73760339

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010985111.8A Pending CN112100941A (en) 2020-09-18 2020-09-18 High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method

Country Status (1)

Country Link
CN (1) CN112100941A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112033812A (en) * 2020-08-12 2020-12-04 成都北方石油勘探开发技术有限公司 Method and system for testing shear-swelling flow conductivity of hydraulic shear fracturing
CN113361127A (en) * 2021-06-24 2021-09-07 北京石油化工学院 Numerical method for simulating transportation process of temporary plugging agent in rough cracks of hot dry rock
CN114048651A (en) * 2021-11-10 2022-02-15 长江大学 Reservoir porous medium temperature coupling model calculation method based on windward GFDM
CN114282451A (en) * 2021-12-22 2022-04-05 中国石油大学(华东) Discrete slot-hole network model connectivity parameter determination method and system
CN115983639A (en) * 2022-12-27 2023-04-18 贵州大学 Evaluation method for water inrush risk of karst aquifer bottom plate
CN116663370A (en) * 2023-07-05 2023-08-29 成都理工大学 Fluid-solid coupling numerical simulation method for deep fracture-cavity type carbonate reservoir
CN117365414A (en) * 2023-09-27 2024-01-09 中国石油大学(北京) Method and device for simulating reservoir fluid-solid damage coupling crack propagation
CN117725632A (en) * 2023-09-22 2024-03-19 中国地震局地球物理研究所 Numerical simulation method for fault nucleation sliding under thermal-water-force multi-field coupling effect

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112033812B (en) * 2020-08-12 2022-11-08 成都北方石油勘探开发技术有限公司 Method and system for testing shear-swelling flow conductivity of hydraulic shear fracturing
CN112033812A (en) * 2020-08-12 2020-12-04 成都北方石油勘探开发技术有限公司 Method and system for testing shear-swelling flow conductivity of hydraulic shear fracturing
CN113361127A (en) * 2021-06-24 2021-09-07 北京石油化工学院 Numerical method for simulating transportation process of temporary plugging agent in rough cracks of hot dry rock
CN113361127B (en) * 2021-06-24 2022-02-18 北京石油化工学院 Numerical method for simulating transportation process of temporary plugging agent in rough cracks of hot dry rock
CN114048651B (en) * 2021-11-10 2023-08-08 长江大学 Reservoir porous medium flow temperature coupling model calculation method based on windward GFDM
CN114048651A (en) * 2021-11-10 2022-02-15 长江大学 Reservoir porous medium temperature coupling model calculation method based on windward GFDM
CN114282451A (en) * 2021-12-22 2022-04-05 中国石油大学(华东) Discrete slot-hole network model connectivity parameter determination method and system
CN115983639A (en) * 2022-12-27 2023-04-18 贵州大学 Evaluation method for water inrush risk of karst aquifer bottom plate
CN116663370A (en) * 2023-07-05 2023-08-29 成都理工大学 Fluid-solid coupling numerical simulation method for deep fracture-cavity type carbonate reservoir
CN116663370B (en) * 2023-07-05 2023-10-24 成都理工大学 Fluid-solid coupling numerical simulation method for deep fracture-cavity type carbonate reservoir
CN117725632A (en) * 2023-09-22 2024-03-19 中国地震局地球物理研究所 Numerical simulation method for fault nucleation sliding under thermal-water-force multi-field coupling effect
CN117725632B (en) * 2023-09-22 2024-05-31 中国地震局地球物理研究所 Numerical simulation method for fault nucleation sliding under thermal-water-force multi-field coupling effect
CN117365414A (en) * 2023-09-27 2024-01-09 中国石油大学(北京) Method and device for simulating reservoir fluid-solid damage coupling crack propagation

Similar Documents

Publication Publication Date Title
CN112100941A (en) High-temperature fracture-cavity reservoir thermo-fluid-solid coupling numerical simulation method
Aliyu et al. Sensitivity analysis of deep geothermal reservoir: Effect of reservoir parameters on production temperature
Asai et al. Efficient workflow for simulation of multifractured enhanced geothermal systems (EGS)
Aliyu et al. Optimum control parameters and long-term productivity of geothermal reservoirs using coupled thermo-hydraulic process modelling
Fu et al. An explicitly coupled hydro‐geomechanical model for simulating hydraulic fracturing in arbitrary discrete fracture networks
Hayashi et al. Numerical models of HDR geothermal reservoirs—a review of current thinking and progress
Yao et al. Effects of fracture density, roughness, and percolation of fracture network on heat-flow coupling in hot rock masses with embedded three-dimensional fracture network
Ren et al. A fully coupled XFEM-EDFM model for multiphase flow and geomechanics in fractured tight gas reservoirs
Gee et al. Multiscale short-circuiting mechanisms in multiple fracture enhanced geothermal systems
Chen et al. Productivity evaluation of unconventional reservoir development with three-dimensional fracture networks
Shook et al. Use of tracers and temperature to estimate fracture surface area for EGS reservoirs
Xue et al. A fast numerical method and optimization of 3D discrete fracture network considering fracture aperture heterogeneity
Juliusson et al. Optimization of injection scheduling in fractured geothermal reservoirs
Pruess et al. Proximity functions for modeling fluid and heat flow in reservoirs with stochastic fracture distributions
Wang et al. A 3D thermal-poroelastic model for geothermal reservoir stimulation
Jing et al. A 3-D water/rock chemical interaction model for prediction of HDR/HWR geothermal reservoir performance
Karvounis et al. Towards a real-time forecast of induced seismicity for enhanced geothermal systems
Chen et al. Application of the finite volume method for geomechanics calculation and analysis on temperature dependent poromechanical stress and displacement fields in enhanced geothermal system
Wu et al. A New Projection‐Based Integrally Embedded Discrete Fracture Model and Its Application in Coupled Flow and Geomechanical Simulation for Fractured Reservoirs
Wang et al. A 3D thermal-poroelastic model for naturally fractured geothermal reservoir stimulation
Zhang et al. Simulation of flow in multi-scale porous media using the lattice boltzmann method on quadtree grids
Srinivasan et al. Transient flow modeling in fractured media using graphs
Shi et al. Performance analysis of multi-well EGS system based on unique network structure—Voronoi fractures
CN114638137B (en) Hot-dry rock heat production prediction method based on heat-flow-solid-damage coupling
Karvounis et al. Modeling of flow and transport in enhanced geothermal systems

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination