Classification method of bedrock heat storage ground and heat field in broken basin, electronic equipment and medium

Abstract

The invention discloses a classification method for a bedrock heat storage geothermal field in a broken basin, electronic equipment and a medium. The method comprises the following steps: compiling a geologic section of a trunk of the basin, and identifying a geologic structure type of a geothermal field in the broken basin; establishing a geothermal field geologic model, and compiling an actually measured formation temperature change curve traversing a geothermal field heat storage top surface depth line to obtain a geothermal profile; numerical simulation is carried out on the geothermal field geologic model, and thermophysical parameters are determined; carrying out heat conduction numerical simulation on the geological section of the basin trunk; different geothermal field bed rock heat storage top surface stratum temperatures are determined, and geothermal anomaly is analyzed; and establishing a geothermal field classification system table, making a judgment map, and dividing the type of each geothermal field in the broken basin. According to the method, the tectonic deformation style is introduced into geothermal field type division, so that spatial distribution of heat storage of bedrock of different tectonic zones is distinguished, the heat storage temperature range is effectively predicted, and the quality of geothermal resources and the development prospect of the geothermal resources can be quickly judged.

Description

Technical Field

[0001] The present invention relates to the field of geothermal exploration and development, and more specifically, to a classification method, electronic equipment and medium for bedrock heat reservoir geothermal fields in a fault basin. Background Art

[0002] The bedrock carbonate reservoirs in the fault basins have become the first choice for geothermal exploration and development due to their high temperature, large water volume, and easy recharge. At present, my country has developed geothermal heating areas of bedrock reservoirs in more than 20 urban areas in Tianjin, Hebei, Shandong, and Shanxi, covering an area of ​​more than 60 million square meters. However, for my country's vast Neogene fault basins, both development practice and theoretical understanding are still in the initial stage. It is urgent to explore a set of practical bedrock reservoir geothermal field classification methods to quickly determine the quality of geothermal resources in the target area and its development prospects.

[0003] At present, there are few studies on the classification of geothermal reservoirs in bedrock carbonate rocks in fault basins. For example, Zhou Ruiliang et al. (1989) divided geothermal fields in a basin into five categories: deep circulation hot spring type geothermal fields in basin edge faults, shallow buried convection type low-temperature geothermal fields in basin edge bedrock, medium-temperature geothermal fields with high uplift and high bulge convection-conduction type in bedrock within the basin, medium-high temperature geothermal fields with low bulge convection-conduction type in bedrock within the basin, and high-temperature and high-pressure geothermal fields with deep depression and deep sag conduction type in the basin based on the genesis of the geothermal fields, the structural characteristics of the distribution area, the reservoir-caprock combination, the reservoir and bedrock burial depth, and the reservoir hot water temperature; Zhao Yonggang et al. (2019) divided geothermal fields in a basin into five categories based on the geothermal fields of carbonate rocks. Based on the product of the reservoir coefficient (ratio of permeability to porosity) and thermal property parameters (thermal conductivity, specific heat capacity and thermal diffusivity), carbonate geothermal reservoirs are divided into three categories, of which Class I reservoirs are high-quality reservoirs, Class II reservoirs are second, and Class III reservoirs are the worst; Zheng Ronghua et al. (2019) divided carbonate thermal reservoirs into four categories: layer-controlled type, layered type, quasi-layered type, and fault zone (group) type based on a large amount of geothermal formation profile measured data and pumping test data, as well as resistivity curve morphological characteristics. These classification methods mostly focus on the heat transfer mode of geothermal fields, the thermal and electrical properties of reservoirs, and lack a classification method for rapid and effective evaluation of bedrock carbonate thermal reservoirs as the exploration target layer.

[0004] There is a need to develop a classification method, electronic equipment and media for bedrock thermal reservoir geothermal fields in fault basins.

[0005] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0006] The present invention proposes a classification method, electronic equipment and medium for bedrock heat reservoir geothermal fields in fault basins, which introduces structural deformation patterns into the classification of geothermal field types, thereby distinguishing the spatial distribution of bedrock heat reservoirs in different structural belts and effectively predicting the temperature range of the heat reservoir, so as to quickly determine the quality of its geothermal resources and its development prospects.

[0007] In a first aspect, an embodiment of the present disclosure provides a method for classifying bedrock thermal reservoir geothermal fields in a fault basin, comprising:

[0008] Prepare the main geological profile of the basin and identify the geological structure types of geothermal fields in the fault basin;

[0009] Establish a geothermal field geological model, compile a measured stratum temperature change curve across the top depth line of the geothermal field heat reservoir, and obtain a geothermal profile;

[0010] Performing numerical simulation on the geological model of the geothermal field to determine the thermophysical parameters;

[0011] Conduct numerical simulation of heat conduction in the main geological section of the basin;

[0012] Determine the top surface temperature of bedrock thermal reservoirs in different geothermal fields and analyze geothermal anomalies;

[0013] Establish a geothermal field classification system table, make a judgment map, and classify the types of geothermal fields in the fault basin.

[0014] Preferably, the main geological profile of the basin is compiled to identify the geological structure types of geothermal fields in the fault basin, including:

[0015] Based on the interpretation results of seismic survey lines, the main geological profile of the basin is compiled to determine the boundaries of different structural deformation units in the basin, that is, the boundaries of different geothermal fields;

[0016] Based on the interpretation results of seismic profiles, identify the structural style of the geothermal field and summarize its spatial distribution characteristics;

[0017] Combined with drilling stratification data, the geological structure types of geothermal fields are divided according to the development layer, burial depth and spatial distribution characteristics of the bedrock heat reservoir.

[0018] Preferably, establishing a geothermal field geological model includes:

[0019] For bedrock thermal reservoirs, the geothermal field geological model is described according to the three-layer structure of reservoir, surrounding rock and caprock.

[0020] Preferably, compiling a geothermal profile comprises:

[0021] According to the drilling data, geological structure and regional geothermal gradient variation law, a measured stratum temperature variation curve crossing the top depth line of the geothermal field heat reservoir is compiled to obtain the geothermal profile.

[0022] Preferably, performing numerical simulation on the geothermal field geological model includes:

[0023] Gridding the geothermal field geological model, and then performing initial assignment of thermal conductivity to obtain a numerical model;

[0024] The boundary conditions of the numerical model are set, and the finite element numerical analysis method is used to solve the two-dimensional steady-state heat conduction equation without internal heat source, and the distribution characteristics of the geothermal field temperature field are obtained by forward modeling.

[0025] Preferably, the two-dimensional steady-state heat conduction equation without internal heat source is:

[0026] K ▽ 2 T=0

[0027] Where K is the diffusion rate, ▽ 2 is the Laplace operator, and T is the distribution function of temperature in the medium (relative to position and time).

[0028] Preferably, determining the thermophysical property parameters comprises:

[0029] The depth of the top surface of the bedrock heat reservoir of the geothermal field is selected as the baseline, and the lateral variation curve of the formation temperature of the depth line is output and compared with the measured formation temperature variation curve. If the conformity rate is less than the set threshold, the value of the thermophysical parameter is adjusted until the conformity rate of the simulated lateral variation curve of the formation temperature and the measured formation temperature variation curve reaches the set threshold. The thermophysical parameter at this time is the thermophysical parameter suitable for the simulation analysis of the entire basin.

[0030] Preferably, the heat conduction numerical simulation of the main geological section of the basin includes:

[0031] Gridding the geothermal geological profile, assigning thermal conductivity, and obtaining a numerical model of the main geological profile;

[0032] Digital simulation of heat conduction is carried out according to boundary conditions, and the distribution map of geothermal field of main geological section is output.

[0033] In a second aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0034] A memory storing executable instructions;

[0035] A processor runs the executable instructions in the memory to implement the classification method of bedrock thermal reservoir geothermal fields in fault basins.

[0036] In a third aspect, the embodiments of the present disclosure further provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for classifying bedrock thermal reservoir geothermal fields in a fault basin.

[0037] Its beneficial effects are:

[0038] The present invention can comprehensively grasp the geothermal resource quality of bedrock heat reservoirs in geothermal fields in a widely deformed fault basin, and effectively predict the buried depth and temperature range of the heat reservoirs, which has important guiding significance for the determination of geothermal exploration target areas in fault basins and the economic evaluation of geothermal projects.

[0039] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0041] Figure 1 A flow chart showing the steps of a method for classifying a bedrock thermal reservoir geothermal field in a fault basin according to an embodiment of the present invention.

[0042] Figure 2 A schematic diagram showing the identification of geological structure types of geothermal fields in a fault basin according to an embodiment of the present invention is shown.

[0043] Figure 3a , Figure 3b , Figure 3c A three-layer geological structure model of a typical geothermal field, a numerical simulation model, and a schematic diagram comparing the simulation and actual measurement of geothermal anomalies of a thermal reservoir according to an embodiment of the present invention are respectively shown.

[0044] Figure 4a , Figure 4b Schematic diagrams of a numerical model of a main geological profile and a geothermal field simulation result according to an embodiment of the present invention are respectively shown.

[0045] Figure 5a , Figure 5b Schematic diagrams of the main section thermal reservoir formation temperature and the cap layer geothermal gradient distribution curves according to an embodiment of the present invention are respectively shown.

[0046] Figure 6A simplified diagram for distinguishing the types of geothermal fields in bedrock thermal reservoirs of sedimentary basins according to an embodiment of the present invention is shown.

[0047] Figure 7 A plan distribution diagram of geothermal field types in bedrock thermal reservoirs of a sedimentary basin according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0049] The present invention provides a classification method for bedrock thermal reservoir geothermal fields in a fault basin, comprising:

[0050] Prepare the main geological profile of the basin and identify the geological structure types of geothermal fields in the fault basin;

[0051] Establish a geothermal field geological model, compile a measured stratum temperature change curve across the top depth line of the geothermal field heat reservoir, and obtain a geothermal profile;

[0052] Conduct numerical simulation on the geological model of geothermal field and determine the thermophysical parameters;

[0053] Conduct numerical simulation of heat conduction in the main geological section of the basin;

[0054] Determine the top surface temperature of bedrock thermal reservoirs in different geothermal fields and analyze geothermal anomalies;

[0055] Establish a geothermal field classification system table, make a judgment map, and classify the types of geothermal fields in the fault basin.

[0056] In one example, the main geological section of the basin was compiled to identify the geological structure types of geothermal fields in the fault basin, including:

[0057] Based on the interpretation results of seismic survey lines, the main geological profile of the basin is compiled to determine the boundaries of different structural deformation units in the basin, that is, the boundaries of different geothermal fields;

[0058] Based on the interpretation results of seismic profiles, identify the structural style of the geothermal field and summarize its spatial distribution characteristics;

[0059] Combined with drilling stratification data, the geological structure types of geothermal fields are divided according to the development layer, burial depth and spatial distribution characteristics of the bedrock heat reservoir.

[0060] In one example, building a geologic model of a geothermal field includes:

[0061] For bedrock thermal reservoirs, the geological model of the geothermal field is described according to the three-layer structure of reservoir, surrounding rock and cap rock.

[0062] In one example, compiling a geothermal profile includes:

[0063] Based on the drilling data, geological structure and regional geothermal gradient variation law, a measured stratum temperature variation curve crossing the top depth line of the geothermal field heat reservoir is compiled to obtain the geothermal profile.

[0064] In one example, performing numerical simulations on a geothermal field geological model includes:

[0065] The geothermal field geological model is gridded, and then the initial value of thermal conductivity is assigned to obtain the numerical model;

[0066] The boundary conditions of the numerical model are set, and the finite element numerical analysis method is used to solve the two-dimensional steady-state heat conduction equation without internal heat source, and the distribution characteristics of the geothermal field temperature field are obtained by forward modeling.

[0067] In one example, the two-dimensional steady-state heat conduction equation without internal heat source is:

[0068] K ▽ 2 T=0

[0069] Where K is the diffusion rate, ▽ 2 is the Laplace operator, and T is the distribution function of temperature in the medium (relative to position and time).

[0070] In one example, determining the thermophysical property parameter includes:

[0071] The depth of the top surface of the bedrock heat reservoir of the geothermal field is selected as the baseline, and the lateral variation curve of the formation temperature of the depth line is output and compared with the measured formation temperature variation curve. If the coincidence rate is less than the set threshold, the value of the thermophysical parameter is adjusted until the coincidence rate of the simulated lateral variation curve of the formation temperature and the measured formation temperature variation curve reaches the set threshold. The thermophysical parameters at this time are the thermophysical parameters suitable for the simulation analysis of the entire basin.

[0072] In one example, numerical simulation of heat conduction in the main geological section of a basin includes:

[0073] Grid processing is performed on the geothermal geological profile, thermal conductivity is assigned, and the numerical model of the main geological profile is obtained;

[0074] Digital simulation of heat conduction is carried out according to boundary conditions, and the distribution map of geothermal field of main geological section is output.

[0075] Specifically, for a sedimentary basin composed mainly of solid rock, heat conduction is the main mode of heat transfer. Therefore, when the heat flow of the basin basement is determined, the main factor restricting the difference in heat conduction between different tectonic zones in the basin is the magnitude of thermal conductivity. The predecessors first used statistical methods to summarize that the surface heat flow and shallow geothermal gradient in the uplift area of ​​the basin are higher than those in the depression area, and the amplitude can reach 30% to 40% of the average value, thus forming a local geothermal anomaly area; and attributed this phenomenon to the heat flow disturbance caused by the high-conductivity bedrock bulge, that is, the heat flow undergoes "thermal refraction" and "heat flow redistribution" during the conduction process. In fact, in addition to the necessary condition of high-conductivity bedrock bulge, the formation of shallow geothermal anomalies is also related to factors such as the thermal sealing ability of the cap rock, the amplitude of the bedrock bulge, and the thermal conductivity ratio between the bedrock and the cap rock. In order to further quantitatively characterize the relationship between shallow geothermal anomalies and their influencing factors, many scholars have conducted fruitful explorations with the help of numerical simulations, and have achieved semi-quantitative results such as "asymmetric mirror image of geothermal field" and "depth of thermal conductivity equilibrium line" in uplift zones. In order to effectively guide production practice with these results, we have invented a geothermal field classification method that combines the differences in structural deformation styles of non-tectonic zones in the basin to semi-quantitatively characterize the relationship between the size of thermal anomalies in different tectonic zones and their bedrock geological structures (including uplift morphology and cover thickness, etc.), providing a basis for selecting favorable zones for bedrock thermal reservoirs in a basin.

[0076] Based on the interpretation results of multiple seismic survey lines, one or several geological profiles that cross the entire fault basin and can reflect the main deformation characteristics are compiled to determine the boundaries of different structural deformation units in the basin, that is, the boundaries of different geothermal fields. According to the interpretation results of seismic profiles, the structural deformation styles of different geothermal fields are identified, such as (semi) grabens, (semi) horsts, slope belts, basin margin fault uplift belts, etc., and their spatial distribution characteristics are summarized. Combined with drilling stratification data, according to the development layer of bedrock heat reservoirs, burial depth and spatial distribution characteristics of bedrock heat reservoirs, the geological structure types of bedrock heat reservoirs in different geothermal fields are divided, such as bulges, depressions, gentle slopes, uplifts, etc.

[0077] Select a geothermal field with a high degree of exploration in the fault basin (such as a certain uplift zone in the geothermal geological profile that crosses the entire fault basin), and characterize the geological model according to the three-layer structure of reservoir, surrounding rock and cap rock for the bedrock (carbonate rock) heat reservoir. Use drilling temperature measurement and other data, combined with the geological structure and regional geothermal gradient change law, to compile a formation temperature change curve that crosses the top depth line of the heat reservoir of a typical geothermal field, which is used as the test condition for the simulation of the geothermal field of a typical geothermal field.

[0078] For the selected geothermal field, according to the thickness of each stratum interpreted by the seismic profile, the three-layer geological structure of the cap rock, surrounding rock, and (bedrock) reservoir is gridded, and the initial thermal conductivity is assigned according to the average thermal conductivity of the stratum, which are k1 , k 2 , k 3 . Set the boundary conditions of the above typical numerical model, such as the average surface temperature T 0 , uniform heat flow q of the base, simulation time length t, etc., the finite element numerical analysis method is used to solve the two-dimensional steady-state heat conduction equation without internal heat source, and the distribution characteristics of the current ground (layer) temperature (degree) field of the typical geothermal field can be obtained by forward modeling. The depth of the top surface of the bedrock heat reservoir of the typical geothermal field is selected as the baseline, and the lateral change curve of the formation temperature of the depth line is output and compared with the measured formation temperature change curve of the same depth. If the conformity rate is less than the set threshold, the values ​​of the thermal physical parameters of the cap rock, surrounding rock, and reservoir are adjusted respectively, that is, k 1 , k 2 , k 3 The size of k is re-simulated, output, and compared until the coincidence rate between the simulated lateral change curve of the formation temperature and the measured curve reaches or exceeds the set threshold. 1 , k 2 , k 3 The value of is the thermophysical property parameter applicable to the simulation analysis of the entire basin.

[0079] The numerical simulation of heat conduction in the main geological profile of the basin is carried out in three steps: (1) Numerical processing of the main geological profile: for one or several geothermal geological profiles that cross the basin, gridding is performed according to the three-layer geological structure of the cap rock, surrounding rock, and (bedrock) heat reservoir, and the thermal conductivity is assigned according to the main thermophysical parameters of each geological structure layer determined in step 3, namely, k 1 , k 2 , k 3 ; (2) Numerical simulation of heat conduction: Based on the boundary conditions of the set numerical model and the digital simulation equation of heat conduction, use a computer to perform simulation operations; (3) Result output: In the calculation results, the distribution map of the current ground (layer) temperature (degree) field of the main geological section is output.

[0080] Determination of the top surface stratum temperature of bedrock heat reservoirs in different geothermal fields and analysis of geothermal anomalies. (1) Compilation of stratum temperature curve: Based on the current stratum (stratum) temperature (degree) field data of the main geological profile, the stratum temperature T on the top surface depth line of the bedrock heat reservoir in different geothermal fields (third / fourth level structural units) is compiled. 储 (2) Compilation of the geothermal gradient curve of the cap layer: Based on the value revealed by the top surface temperature curve of the thermal reservoir compiled in the previous step, and the average surface temperature T 0 In contrast, the geothermal gradient G of the thermal cap layer is compiled 盖 The lateral variation curve G 盖 =(T 储 -T 0 ) / H 盖, H 盖 is the thickness of the caprock. (3) Geothermal anomaly analysis: Based on the G 盖 The value of the basin's average geothermal gradient G 0 By comparison, the geothermal gradient anomaly of the thermal cover layer is calculated as △G = G 盖 -G 0 , and from this, the top surface strata of the heat reservoir relative to G 0 Abnormal temperature △T 储 =△G*H 盖 .

[0081] Establish a geothermal field classification system table and make a simple judgment map. First, it is divided into five categories. The naming is based on the structural style of the geological structure of the geothermal field and the structural deformation location of the bedrock thermal reservoir. It is divided into five categories: convex type, concave type, gentle slope type, basin edge convex type, and uplift type; then it is subdivided into 8 small categories. For the convex geothermal field, it is further subdivided into high convex type, medium convex type and low convex type according to the thickness of the cap layer and the height of the bedrock convexity, as well as the resulting changes in the cap layer geothermal gradient and the thermal reservoir geothermal anomaly (that is, the difference from the normal background value); similarly, for the uplift geothermal field, with the thinning of the cap layer thickness and the reduction of thermal sealing performance, The resulting caprock geothermal gradient and thermal reservoir geothermal are both negative anomalies (i.e., less than the normal background value). According to the size of the negative anomaly, they are further subdivided into two subcategories: shallow buried and exposed. A judgment table is established. For the 8-subcategory classification scheme, based on the analysis conclusions, four factors, namely, caprock thickness, bedrock uplift amplitude, caprock geothermal gradient, and thermal reservoir geothermal anomaly, are considered to establish a basis for determining different types of geothermal fields. A simple judgment diagram is prepared: on the bedrock thermal reservoir temperature-depth diagram, the change in caprock geothermal gradient is used as the main basis for judgment, combined with the size of the caprock thickness and the difference in background values, a simple judgment diagram for thermal reservoir classification is compiled.

[0082] Classify the types of geothermal fields in the fault basin. On the cross-section, identify the geothermal field types in different structural belts in the cross-section according to the bedrock thermal reservoir structure style, geological structure type, thermal reservoir top surface burial depth, and caprock geothermal gradient; compile a planar distribution map of geothermal field types in the entire fault basin based on the distribution of geothermal field types on the main section.

[0083] The present invention also provides an electronic device, which includes: a memory storing executable instructions; a processor, which runs the executable instructions in the memory to implement the above-mentioned classification method of bedrock heat reservoir geothermal fields in fault basins.

[0084] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned classification method for bedrock thermal reservoir geothermal fields in fault basins.

[0085] To facilitate understanding of the solutions and effects of the embodiments of the present invention, three specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0086] Example 1

[0087] Figure 1 A flow chart showing the steps of a method for classifying a bedrock thermal reservoir geothermal field in a fault basin according to the present invention.

[0088] like Figure 1 As shown, the classification method of the bedrock heat reservoir geothermal field in the fault basin includes: step 101, compiling the main geological profile of the basin, and identifying the geological structure type of the geothermal field in the fault basin; step 102, establishing a geothermal field geological model, compiling a measured formation temperature change curve that crosses the top depth line of the geothermal field heat reservoir, and obtaining a geothermal profile; step 103, performing numerical simulation on the geothermal field geological model, and determining thermophysical parameters; step 104, performing numerical simulation of heat conduction of the main geological profile of the basin; step 105, determining the formation temperature of the top surface of the bedrock heat reservoir of different geothermal fields, and analyzing geothermal anomalies; step 106, establishing a geothermal field classification system table, making a judgment diagram, and dividing the types of various geothermal fields in the fault basin.

[0089] Figure 2 A schematic diagram showing the identification of geological structure types of geothermal fields in a fault basin according to an embodiment of the present invention is shown.

[0090] Based on the interpretation results of multiple seismic survey lines, we compile one or several geological profiles that cross the entire fault basin and can reflect the main deformation characteristics, and determine the boundaries of different structural deformation units in the basin, that is, the boundaries of different geothermal fields. Based on the interpretation results of seismic profiles, we identify the structural deformation styles of different geothermal fields, such as (semi) grabens, (semi) horsts, slope zones, basin margin fault uplift zones, etc., and summarize their spatial distribution characteristics. Combined with drilling stratification data, according to the development layer of the bedrock heat reservoir, burial depth and spatial distribution characteristics of the bedrock heat reservoir, the geological structure types of bedrock heat reservoirs in different geothermal fields are divided, such as bulges, depressions, gentle slopes, uplifts, etc. Figure 2 shown.

[0091] Figure 3a , Figure 3b , Figure 3c A three-layer geological structure model of a typical geothermal field, a numerical simulation model, and a schematic diagram comparing the simulation and actual measurement of geothermal anomalies of a thermal reservoir according to an embodiment of the present invention are respectively shown.

[0092] Select a geothermal field with a high degree of exploration in the fault basin (such as a certain uplift zone in the geothermal geological profile that crosses the entire fault basin), and characterize the geological model according to the three-layer structure of reservoir, surrounding rock and cap rock for the bedrock (carbonate rock) thermal reservoir, such as Figure 3a Using drilling temperature measurement data, combined with geological structure and regional geothermal gradient change law, a formation temperature change curve across the top depth line of the heat reservoir in a typical geothermal field is compiled as a test condition for the simulation of the geothermal field in a typical geothermal field.

[0093] For the selected geothermal field, according to the thickness of each stratum interpreted by the seismic profile, the three-layer geological structure of the cap rock, surrounding rock, and (bedrock) reservoir is gridded, and the initial thermal conductivity is assigned according to the average thermal conductivity of the stratum, which are k 1 , k 2 , k 3 , distinguished by different colors, such as Figure 3b shown.

[0094] Set the boundary conditions of the above typical numerical model, such as the average surface temperature T 0 , uniform heat flow q of the basement, simulation time length t, etc., the finite element numerical analysis method is used to solve the two-dimensional steady-state heat conduction equation without internal heat source, and the distribution characteristics of the current ground (layer) temperature (degree) field of the typical geothermal field can be obtained by forward modeling. The depth of the top surface of the bedrock heat reservoir of the typical geothermal field is selected as the baseline, and the lateral change curve of the formation temperature of the depth line is output and compared with the measured formation temperature change curve of the same depth. If the conformity rate is less than 85%, the values ​​of the thermal physical parameters of the cap rock, surrounding rock, and reservoir are adjusted respectively, that is, k 1 , k 2 , k 3 The size of k is re-simulated, output, and compared until the simulated lateral variation curve of the formation temperature and the measured curve are consistent with each other by 85% or more. 1 , k 2 , k 3 The value of is the thermophysical parameter applicable to the simulation analysis of the entire basin, such as Figure 3c shown.

[0095] Figure 4a , Figure 4b Schematic diagrams of a numerical model of a main geological profile and a geothermal field simulation result according to an embodiment of the present invention are respectively shown.

[0096] The numerical simulation of heat conduction in the main geological profile of the basin is carried out in three steps: (1) Numerical processing of the main geological profile: for one or several geothermal geological profiles that cross the basin, gridding is performed according to the three-layer geological structure of the cap rock, surrounding rock, and (bedrock) heat reservoir, and the thermal conductivity is assigned according to the main thermophysical parameters of each geological structure layer determined in step 3, namely, k 1 , k 2 , k 3 ,like Figure 4a (2) Numerical simulation of heat conduction: According to the boundary conditions of the numerical model and the digital simulation equation of heat conduction, the computer is used to perform simulation calculations; (3) Result output: In the calculation results, the distribution map of the current ground (layer) temperature (degree) field of the main geological section is output, as shown in Figure 4b shown.

[0097] Figure 5a , Figure 5b Schematic diagrams of the main section thermal reservoir formation temperature and the cap layer geothermal gradient distribution curves according to an embodiment of the present invention are respectively shown.

[0098] Determination of the top surface stratum temperature of bedrock heat reservoirs in different geothermal fields and analysis of geothermal anomalies. (1) Compilation of stratum temperature curve: Based on the current stratum (stratum) temperature (degree) field data of the main geological profile, the stratum temperature T on the top surface depth line of the bedrock heat reservoir in different geothermal fields (third / fourth level structural units) is compiled. 储 The lateral variation curve of Figure 5a (2) Compilation of the geothermal gradient curve of the cap layer: Based on the value revealed by the top surface temperature curve of the thermal reservoir compiled in the previous step, and the average surface temperature T 0 In contrast (such as North China T 0 =15℃), and the geothermal gradient G of the thermal cap layer is compiled 盖 The lateral variation curve G 盖 =(T 储 -T 0 ) / H 盖 , H 盖 is the thickness of the cap layer, such as Figure 5b (3) Geothermal anomaly analysis: According to the G 盖 The value of the basin's average geothermal gradient G 0 In contrast, North China 0 =3.0℃ / l00m, and the geothermal gradient anomaly of the thermal cover layer is calculated as △G=G 盖 -G 0 , and from this, the top surface strata of the heat reservoir relative to G 0 Abnormal temperature △T 储 =△G*H 盖 .

[0099] Figure 6 A simplified diagram for distinguishing the types of geothermal fields in bedrock thermal reservoirs of sedimentary basins according to an embodiment of the present invention is shown.

[0100] A geothermal field classification system table was established, and a simple judgment chart was made. First, it was divided into five categories. The naming was based on the structural style of the geological structure of the geothermal field and the structural deformation location of the bedrock thermal reservoir. It was divided into five categories: convex type, concave type, gentle slope type, basin edge convex type, and uplift type, as shown in Table 1; then it was subdivided into 8 small categories. For the convex geothermal field, it was further subdivided into three small categories: high convex type, medium convex type, and low convex type, based on the thickness of the cap layer and the height of the bedrock convexity, as well as the resulting changes in the cap layer geothermal gradient and the thermal reservoir geothermal anomaly (i.e., the difference from the normal background value); similarly, for For uplift geothermal fields, as the thickness of the cap layer decreases and the thermal sealing performance decreases, the resulting cap layer geothermal gradient and thermal reservoir geothermal are both negative anomalies (i.e., less than the normal background value). According to the size of the negative anomaly, they are further subdivided into two subcategories: shallow buried type and exposed type, as shown in Table 1. A judgment table is established. For the classification scheme of the eight subcategories, based on the analysis conclusions, considering four factors such as cap layer thickness, bedrock uplift amplitude, cap layer geothermal gradient, and thermal reservoir geothermal anomaly, the judgment basis for different types of geothermal fields is established, as shown in Table 1. For example, according to the cap layer geothermal gradient (G 盖 / ℃ / l00m) from large to small are: high uplift type 5.0~11.0, medium uplift type 4.0~5.0, low uplift type 3.5~4.0, depression type 3.0~3.5, gentle slope type 2.5~3.0, basin edge broken uplift type 2.0~2.5, shallow buried type 1.5~2.0 and exposed type <1.5; make a simple judgment map: on the bedrock thermal reservoir temperature-depth map, take the change of caprock geothermal gradient as the main judgment basis, combine the caprock thickness and background value difference, compile a simple judgment diagram for thermal reservoir classification, such as Figure 6 shown.

[0101] Table 1

[0102]

[0103]

[0104] Figure 7 A plan distribution diagram of geothermal field types in bedrock thermal reservoirs of a sedimentary basin according to an embodiment of the present invention is shown.

[0105] Classify the types of geothermal fields in the fault basin. On the cross-section diagram, according to the bedrock thermal reservoir structural style, geological structure type, thermal reservoir top surface burial depth, and caprock geothermal gradient expressed in Table 1, identify the geothermal field types in different structural belts in the cross-section diagram, such as Figure 5bAs shown; According to the distribution of geothermal field types on the main section, a planar distribution map of geothermal field types in the entire fault basin is compiled, as shown in Figure 7 shown.

[0106] This method first identifies the geological structure type of each geothermal field (i.e., each structural deformation unit) in the fault basin by interpreting the seismic profile in the fault basin; then, typical geothermal fields with a high degree of exploration in the basin are selected for heat conduction simulation, and the simulation results are compared with the measured bedrock thermal reservoir formation temperature to determine the thermophysical parameters of the main structural layers in the basin; then, based on the determined thermophysical parameters, the formation temperature field of the main profile of the entire basin is simulated and the degree of geothermal anomaly of different geothermal fields is determined; finally, based on the configuration relationship between the cap rock thickness and the amplitude of the bedrock uplift and the resulting cap rock geothermal gradient and the abnormal size of the thermal reservoir formation temperature, a geothermal field classification system is established to divide the types of geothermal fields in the fault basin.

[0107] Example 2

[0108] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; a processor running the executable instructions in the memory to implement the above-mentioned classification method of bedrock thermal reservoir geothermal fields in the fault basin.

[0109] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0110] The memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0111] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0112] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present disclosure.

[0113] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0114] Example 3

[0115] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for classifying bedrock thermal reservoir geothermal fields in a fault basin.

[0116] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of each embodiment of the present disclosure are executed.

[0117] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0118] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0119] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A classification method for bedrock thermal reservoir geothermal fields in a fault basin, characterized in that: include: Prepare the main geological profile of the basin and identify the geological structure types of geothermal fields in the fault basin; Establish a geothermal field geological model, compile a measured stratum temperature change curve across the top depth line of the geothermal field heat reservoir, and obtain a geothermal profile; Performing numerical simulation on the geological model of the geothermal field to determine the thermophysical parameters; Conduct numerical simulation of heat conduction in the main geological section of the basin; Determine the top surface temperature of bedrock thermal reservoirs in different geothermal fields and analyze geothermal anomalies; Establish a geothermal field classification system table, make a judgment map, and classify the types of geothermal fields in the fault basin.

2. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 1, wherein: Compile the main geological profile of the basin and identify the geological structure types of geothermal fields in the fault basin, including: Based on the interpretation results of seismic survey lines, the main geological profile of the basin is compiled to determine the boundaries of different structural deformation units in the basin, that is, the boundaries of different geothermal fields; Based on the interpretation results of seismic profiles, identify the structural style of the geothermal field and summarize its spatial distribution characteristics; Combined with drilling stratification data, the geological structure types of geothermal fields are divided according to the development layer, burial depth and spatial distribution characteristics of the bedrock heat reservoir.

3. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 1, wherein: Building a geological model of a geothermal field includes: For bedrock thermal reservoirs, the geothermal field geological model is described according to the three-layer structure of reservoir, surrounding rock and caprock.

4. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 1, wherein: Preparation of geothermal profiles includes: According to the drilling data, geological structure and regional geothermal gradient variation law, a measured stratum temperature variation curve crossing the top depth line of the geothermal field heat reservoir is compiled to obtain the geothermal profile.

5. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 1, wherein: The numerical simulation for the geothermal field geological model includes: Gridding the geothermal field geological model, and then performing initial assignment of thermal conductivity to obtain a numerical model; The boundary conditions of the numerical model are set, and the finite element numerical analysis method is used to solve the two-dimensional steady-state heat conduction equation without internal heat source, and the distribution characteristics of the geothermal field temperature field are obtained by forward modeling.

6. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 5, wherein: The two-dimensional steady-state heat conduction equation without internal heat source is: K·▽ 2 T=0 Where K is the diffusion rate, ▽ 2 is the Laplace operator, and T is the distribution function of temperature in the medium.

7. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 1, wherein: Determine the thermal physical parameters including: The depth of the top surface of the bedrock heat reservoir of the geothermal field is selected as the baseline, and the lateral variation curve of the formation temperature of the depth line is output and compared with the measured formation temperature variation curve. If the conformity rate is less than the set threshold, the value of the thermophysical parameter is adjusted until the conformity rate of the simulated lateral variation curve of the formation temperature and the measured formation temperature variation curve reaches the set threshold. The thermophysical parameter at this time is the thermophysical parameter suitable for the simulation analysis of the entire basin.

8. The classification method of bedrock thermal reservoir geothermal fields in a fault basin according to claim 5, wherein: The numerical simulation of heat conduction in the main geological section of the basin includes: Gridding the geothermal geological profile, assigning thermal conductivity, and obtaining a numerical model of the main geological profile; Digital simulation of heat conduction is carried out according to boundary conditions, and the distribution map of geothermal field of main geological section is output.

9. An electronic device, characterized in that: The electronic device comprises: A memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the method for classifying bedrock thermal reservoir geothermal fields in a fault basin according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for classifying bedrock thermal reservoir geothermal fields in a fault basin according to any one of claims 1 to 8.

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