Multi-scale three-dimensional geologic automatic modeling method for formally expressing stratigraphic sequence

Abstract

A multi-scale three-dimensional geologic automatic modeling method for formally expressing stratigraphic sequences comprises the following steps: S1, performing scale classification on multi-source geologic data and respectively applying the multi-source geologic data to subsequent three-dimensional modeling tasks of geologic structures of various scales; s2, respectively establishing a three-dimensional model of each stratum interface of the regional scale, the engineering scale and the outcrop scale; s3, introducing a concept of a directed curved surface, wherein the curved surface can be converted into a corresponding equivalent entity according to positive and negative directions; s4, the stratigraphic sequence is subjected to formalized expression with the stratigraphic interface models of all scales as basic variables, automatic classification modeling of multiple geologic bodies according to the corresponding stratigraphic sequence constraints is achieved, and fusion of multi-scale geologic models is achieved, the modeling method can achieve objective formalized logic expression of the stratigraphic sequence constraints in the modeling process, and the modeling efficiency is improved. The defect that precision and efficiency are low when the existing research expresses the complex interlayer contact relation of the multi-scale geologic structure is overcome, and automatic classification modeling of the multi-scale geologic structure is achieved.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional geological modeling, and in particular to a multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequences. Background Art

[0002] In the field of three-dimensional geological modeling, the model expression of complex interlayer contact relationships of multi-scale geological structures, such as conformity and unconformity relationships between multiple geological bodies, fault dislocation, fracture development, intrusion and erosion, etc., has always been an important factor affecting modeling accuracy and efficiency. Existing studies generally adopt an interactive modeling method driven by expert knowledge, which realizes the model expression of complex interlayer contact relationships at multiple scales by "cutting and shaping" the geological body model. However, this method involves a large number of interactive model pruning operations when expressing complex interlayer contact relationships between multiple geological bodies, which has a large subjective factor and low efficiency. Since the interlayer contact relationship is essentially a manifestation of stratigraphic sequence logic, the reason why the existing interactive multi-scale geological body modeling method with the dominant idea of ​​"first building a model and then cutting and shaping" has not achieved automatic modeling is that there is a lack of an objective quantitative expression method for stratigraphic sequence logic, resulting in the failure to form corresponding modeling rules for stratigraphic sequence constraints, which in turn leads to the failure of different geological bodies to be automatically classified and modeled according to the corresponding modeling rules and to automatically express interlayer contact relationships, so interactive cutting and shaping are required again after obtaining the preliminary modeling results. Summary of the invention

[0003] The purpose of the present invention is to address the problems of low accuracy and efficiency of existing interactive three-dimensional geological modeling methods driven by expert knowledge when modeling multi-scale complex interlayer contact relationships, and to propose a multi-scale three-dimensional geological automatic modeling method that formally expresses stratigraphic sequences to achieve automatic classification modeling of multi-scale geological structures.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequences, comprising the following steps:

[0006] S1. Scale classification of multi-source geological data and application to subsequent 3D modeling tasks of geological structures at different scales;

[0007] S2. Establish three-dimensional models of stratigraphic interfaces at regional scale, engineering scale and outcrop scale respectively;

[0008] S3. Introduce the concept of directed surface. Each stratum interface has both positive and negative directions, and the surface can be converted into the corresponding equivalent entity according to the positive direction.

[0009] S4. Taking the stratigraphic interface models of various scales as basic variables, the stratigraphic sequence is formally expressed in the form of a directed stratigraphic surface Boolean logic sequence to obtain modeling rules for the unique expression of each stratum, realize automatic classification and modeling of multiple geological bodies according to the corresponding stratigraphic sequence constraints, and realize the fusion of multi-scale geological models.

[0010] In the step S2, the regional scale geological structures include cover layers, rock layers, folds, and faults; the engineering scale geological structures include lenses, fracture zones, pinch-out interlayers, intrusive erosion, and karst; and the outcrop scale geological structures include rock mass structural surfaces and fissures;

[0011] The interface characteristics of the regional scale geological structure in the S2 step are usually single-valued or multi-valued continuous surfaces, which can be modeled by a grid modeling method based on spatial coordinate weighting (such as inverse distance weighting, natural neighbor interpolation, Kriging method, etc.) or a surface modeling method based on function surface (such as non-uniform rational B-spline, polynomial interpolation, minimum curvature interpolation, etc.).

[0012] The interface of the engineering-scale geological structure in step S2 is characterized by a high-genus surface with relatively discrete distribution and multiple internal "hollowings", which can be modeled by an implicit surface modeling method or a subdivision surface method;

[0013] The fracture structural surface characteristics at the outcrop scale in the S2 step are randomly distributed in large quantities and can be modeled using a discrete fracture network modeling method.

[0014] In the step S3, the surface is converted into the corresponding equivalent entity according to the positive direction according to the conversion principle:

[0015] 1) The shape and positive direction of the directed surface are consistent with the shape and positive direction of the corresponding boundary surface of the equivalent entity;

[0016] 2) The positive direction of all boundary surfaces of the equivalent entity is outward.

[0017] The specific process of realizing automatic classification modeling of multiple geological bodies according to corresponding stratigraphic sequence constraints and realizing the fusion of multi-scale geological models in step S4 includes:

[0018] 1) Stratigraphic sequence interpretation and modeling variable determination;

[0019] 2) Setting Level I constraints - geological age and stratigraphic category;

[0020] 3) Setting Level II constraints—faults and intrusion erosion;

[0021] 4) Set up level III constraint—fracture structural surface.

[0022] The beneficial effects of the present invention are as follows: the modeling method of the present invention can realize the objective formalized logical expression of stratigraphic sequence constraints in the modeling process, overcome the shortcomings of existing research in terms of low accuracy and efficiency in expressing complex interlayer contact relationships of multi-scale geological structures, and realize automatic classification modeling of multi-scale geological structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the conversion between the directed surface and the equivalent entity of the present invention;

[0024] Figure 2 It is a directed ground-level Boolean logic operation diagram of the present invention;

[0025] Figure 3 A diagram of a Boolean logic sequence method for formally expressing a stratigraphic sequence of the present invention;

[0026] Figure 4 This is an automatically updated diagram of the multi-scale geological model of the present invention.

[0027] Figure 5 It is a practical application flow chart of the multi-scale three-dimensional geological automatic modeling of the present invention;

[0028] The following is a detailed description of the embodiments of the invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0030] A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequences, comprising the following steps:

[0031] S1. Scale classification of multi-source geological data and application to subsequent 3D modeling tasks of geological structures at different scales;

[0032] S2. Establish three-dimensional models of stratigraphic interfaces at regional scale, engineering scale and outcrop scale respectively;

[0033] Regional-scale geological structures include cover layers, rock layers, folds, and faults; engineering-scale geological structures include lenses, fracture zones, pinch-out interlayers, intrusive erosion, and karst; outcrop-scale geological structures include rock mass structural surfaces and fissures;

[0034] The interface characteristics of regional-scale geological structures are usually single-valued or multi-valued continuous surfaces, which can be modeled using grid modeling methods based on spatial coordinate weighting (such as inverse distance weighting, natural neighbor interpolation, Kriging, etc.) or surface modeling methods based on function surfaces (such as non-uniform rational B-splines, polynomial interpolation, minimum curvature interpolation, etc.).

[0035] The interface of the scale geological structure is characterized by a high-genus surface with relatively discrete distribution and multiple internal "hollowings", which can be modeled by implicit surface modeling method or subdivision surface method;

[0036] The fracture structural surfaces at the outcrop scale are characterized by a large number of random distributions, which can be modeled using the discrete fracture network modeling method.

[0037] S3. Introduce the concept of directed surface. Each stratum interface has both positive and negative directions, and the surface can be converted into the corresponding equivalent entity according to the positive direction.

[0038] In conventional three-dimensional geological modeling methods, geological body models are obtained through interactive modeling operations such as cutting, segmentation, combination, and Boolean operations between multiple stratigraphic (fault) planes and rectangular modeling areas. The more complex the interlayer contact relationship is, the more interactive modeling operations are required for the geological body. Specifically, in the modeling process, a geological body will be divided by a stratigraphic layer once to obtain two adjacent sub-geological bodies. At this time, geological engineers need to judge the stratigraphic category of each sub-geological body and whether subsequent shaping operations are required based on the stratigraphic sequence. The more complex the interlayer contact relationship is, the more subjective judgment and shaping work will be required for the geological body, which will lead to problems such as the modeling results are not closed and the stratigraphic boundaries are not close. If each modeling operation can only obtain one target sub-geological body according to the modeling expectation, then by setting a specific modeling operation sequence and forming corresponding modeling rules, different geological bodies can be automatically classified and modeled, reducing subjective manual intervention, and ensuring that the modeling results are closed and the boundaries are closely fitted. Therefore, in order to achieve the above goals, the concept of directed surfaces is first introduced, stipulating that in the three-dimensional geological modeling process, any spatial surface has positive and negative directions, and the surface can be converted into a corresponding equivalent entity according to the positive direction.

[0039] The conversion principles between directed surfaces and equivalent solids are as follows and Figure 1 As shown:

[0040] 1) The shape and positive direction of the directed surface are consistent with the shape and positive direction of the corresponding boundary surface of the equivalent entity;

[0041] 2) The positive direction of all boundary surfaces of the equivalent entity is outward.

[0042] According to the principle of equivalent entities, the Boolean segmentation, clipping and combination operations between stratigraphic layers in the 3D geological modeling process can be uniquely converted into Boolean logic between equivalent entities, such as Figure 2 shown.

[0043] S4. Taking the stratigraphic interface models of various scales as basic variables, the stratigraphic sequence is formally expressed in the form of a directed stratigraphic surface Boolean logic sequence to obtain modeling rules for the unique expression of each stratum, realize automatic classification and modeling of multiple geological bodies according to the corresponding stratigraphic sequence constraints, and realize the fusion of multi-scale geological models.

[0044] Based on the conversion principle between directed stratigraphic interfaces and equivalent entities, the stratigraphic layer is used as the input variable, and the stratigraphic sequence is constructed through the Boolean operation logic sequence expression between multiple directed stratigraphic layers, so that multiple geological bodies can be automatically classified and modeled according to the corresponding stratigraphic sequence constraints, and the fusion of multi-scale geological models can be realized. The specific process includes: Figure 3 The 4 steps shown are:

[0045] 1) Stratigraphic sequence interpretation and modeling variable determination

[0046] According to the original geological data obtained (such as geological drilling and geological profiles), the stratigraphic sequence is interpreted. The interpretation content includes geological age and stratigraphic deposition order, judgment of new and old faults, contact relationship between faults and various strata, development of intrusion and erosion, and distribution of fracture structural surfaces. Then, the multi-scale geological modeling task variables are determined according to the interpretation results. Under normal circumstances, the variables can be mainly classified into stratigraphic interfaces, fault planes, intrusion and erosion and other high-deficient geological body boundary surfaces and discrete fracture network DFN models. The geological body modeling rules are expressed through the above variables. Since the stratigraphic evolution process is generally new at the top and old at the bottom, and is accompanied by tectonic activities such as folds, faults, intrusions and erosion, it is also necessary to comply with the laws of stratigraphic evolution when setting modeling rules. The above variables are divided into three levels of constraints, namely, level I constraints - primary structures such as geological age and stratigraphic categories; level II constraints - secondary structures such as faults and intrusions and erosion; level III constraints - DFN model simulation of stratigraphic fracture development. In Figure 3 In the figure, through stratigraphic interpretation, it can be seen that there are four target strata A, B, C, and D in the example area. The stratigraphic order is from new to old, and the corresponding stratigraphic layers are S1, S2, and S3, respectively. There is an intrusive body Es in stratum A; there are two faults F1 and F2, among which strata B, C, and D are affected by fault F1, and strata C and D are affected by fault F2. F1 was formed earlier than F2; fractures are only developed in stratum C.

[0047] 2) Setting Level I constraints - geological age and stratigraphic category

[0048] The stratigraphic plane is the interface between strata. It is used to represent the stratigraphic deposition process of the primary structure in the directed stratigraphic plane Boolean logic sequence method and is the first-level constraint in the modeling process. The stratigraphic plane is obtained by interpolating the original geological data through the corresponding geological interpolation method, and different types of stratigraphic planes can be established according to different engineering requirements, such as geological age, rock and soil attribute category, surrounding rock grade, weathering degree and corresponding various combinations. Let G be the modeling area, Figure 3 Taking the stratigraphic layers S1, S2, and S3 as examples, the modeling rules for stratigraphic layers A, B, C, and D are expressed as follows:

[0049] A is the topmost stratum, involving the stratum S1. The modeling rule can be expressed as the entire modeling area G minus the part below S1. According to the principle of conversion between directed surfaces and equivalent entities, the part below S1 can be expressed as _ S __ 1 _ , that is, the S1 stratigraphic layer with the direction upward. Therefore, the modeling rule of stratigraphic layer A is A=G- _ S __ 1 _ .

[0050] B is in contact with A and C, involving the stratigraphic layers S1 and S2. The modeling rule can be expressed as the entire modeling area G minus the part above S1 and the part below S2, that is,

[0051] C is in contact with B and D, involving the stratigraphic layers S2 and S3. The modeling rule can be expressed as the entire modeling area G minus the part above S1, the part above S2, and the part below S3, that is,

[0052] D is in contact with C, involving the stratigraphic layers S2 and S3. The modeling rule can be expressed as the entire modeling area G minus the part above S1, the part above S2, and the part above S3, that is, D = G- S1 - S2 - S3 .

[0053] 3) Setting Level II Constraints—Faults and Intrusion Erosion

[0054] Figure 3 In the example area, there is an intrusion Es in the A formation, where the intrusion Es is a high-genus closed surface. Therefore, the modeling rule of the A formation can be expressed as:

[0055] The BCD strata have faults F1F2. According to the old and new order of F1F2, the modeling area can be divided into three parts: F1 upper plate, F1 lower plate-F2 upper plate, F1 lower plate-F2 upper plate. Under normal circumstances, faults will only cause relative displacement of the upper and lower plates, and will not change the original stratigraphic sequence in the plate. Therefore, the stratigraphic sequence constraints of each plate are consistent with the original stratigraphic sequence constraints. Therefore, the modeling rules of the strata in each plate of the fault do not need to be changed, and only the modeling area G needs to be changed. Then, according to the old and new order of the faults, the fault constraints are added to the modeling rules of the strata in each plate, specifically:

[0056] For the F1 hanging wall, the initial modeling area is the entire BCD strata minus the part below fault F1, so the modeling rules for each stratum in the F1 hanging wall can be expressed as

[0057] For the F1 footwall, fault F2 only affects strata CD but not strata B. Therefore, the modeling rules for the F2 upper and lower strata are set according to the method of processing the strata in the F1 upper strata. The modeling rules for the strata in the F2 upper strata are as follows: The modeling rules for each stratum in the F2 footwall are: D=G- S1 - F1 - F2 - S2 - S3 .

[0058] 4) Setting Level III Constraints - Fracture Structural Surfaces

[0059] Finally, add the DFN model constraints. Figure 3 In this example, the fracture only exists in stratum C, so only stratum C needs to be added with fracture constraints, that is, F2 lower plate

[0060] By establishing the above modeling logic, the multi-scale three-dimensional fusion automatic modeling of engineering geology is realized, and automatic updates can be achieved by adjusting the modeling variables at each level, such as Figure 4 shown.

[0061] The actual application process of multi-scale three-dimensional geological automatic modeling according to the present invention is as follows: Figure 5 shown.

[0062] In the description of the invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0064] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be mechanically connected, electrically connected, or able to communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0065] The invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the invention, or they are directly applied to other occasions without improvement, they are all within the scope of protection of the invention.

Claims

1. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence, characterized in that: The following steps are involved: S1. Scale classification of multi-source geological data and application to subsequent 3D modeling tasks of geological structures at different scales; S2. Establish three-dimensional models of stratigraphic interfaces at regional scale, engineering scale and outcrop scale respectively; S3. Introduce the concept of directed surface. Each stratum interface has both positive and negative directions, and the surface can be converted into the corresponding equivalent entity according to the positive direction. S4. Taking the stratigraphic interface models of various scales as basic variables, the stratigraphic sequence is formally expressed in the form of a directed stratigraphic surface Boolean logic sequence to obtain modeling rules for the unique expression of each stratum, realize automatic classification and modeling of multiple geological bodies according to the corresponding stratigraphic sequence constraints, and realize the fusion of multi-scale geological models.

2. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 1, characterized in that: The regional scale geological structures in step S2 include cover layers, rock layers, folds, and faults; Engineering-scale geological structures include lenses, fracture zones, pinch-out interlayers, intrusive erosion, and karst; outcrop-scale geological structures include rock structural surfaces and fissures.

3. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 2, characterized in that: The interface characteristics of the regional scale geological structure in the step S2 are usually single-valued or multi-valued continuous surfaces, which can be modeled by a grid modeling method based on spatial coordinate weighting or a surface modeling method based on a function surface.

4. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 3, characterized in that: The interface of the engineering-scale geological structure in the step S2 is characterized by a high-genus surface with a relatively discrete distribution and multiple internal "hollowings", which can be modeled by an implicit surface modeling method or a subdivision surface method.

5. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 4, characterized in that: The fracture structural surface characteristics at the outcrop scale in the S2 step are randomly distributed in large quantities and can be modeled using a discrete fracture network modeling method.

6. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 5, characterized in that: In the step S3, the surface is converted into the corresponding equivalent entity according to the positive direction according to the conversion principle: 1) The shape and positive direction of the directed surface are consistent with the shape and positive direction of the corresponding boundary surface of the equivalent entity; 2) The positive direction of all boundary surfaces of the equivalent entity is outward.

7. A multi-scale three-dimensional geological automatic modeling method for formally expressing stratigraphic sequence according to claim 6, characterized in that: The specific process of realizing automatic classification modeling of multiple geological bodies according to corresponding stratigraphic sequence constraints and realizing the fusion of multi-scale geological models in step S4 includes: 1) Stratigraphic sequence interpretation and modeling variable determination; 2) Setting Level I constraints - geological age and stratigraphic category; 3) Setting Level II constraints—faults and intrusion erosion; 4) Set up level III constraint—fracture structural surface.

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