Underground fluid migration accurate inversion method and system based on Beidou satellite observation

Abstract

The invention discloses an accurate inversion method and system for underground fluid migration based on Beidou satellite observation. According to the method, the surface radar image is obtained from the Beidou satellite, accurate inversion of the actual displacement condition of the target stratum and the underground fluid migration condition can be achieved after geological exploration is completed, and the accuracy of sensing the underground fluid migration condition is improved. Regional stratum information is obtained through a geological exploration means, and after a Beidou satellite obtains an earth surface radar image, the data are transmitted to the system; the system carries out preprocessing, interference factors are eliminated, and a digital elevation model is generated; the system takes a digital elevation model as a calculation model, a finite element method is adopted to accurately calculate the model, the accurate value of each stratum displacement is obtained, and a corresponding result and a cloud picture are generated; and a sensing unit of the system judges the migration condition of the underground fluid according to the displacement of each stratum to generate a corresponding result and a cloud picture.

Description

Technical Field

[0001] The present invention relates to the field of satellite observation and numerical simulation, and in particular to an accurate inversion method and system for underground fluid migration based on Beidou satellite observation. Background Art

[0002] The migration process of underground fluids has important application value in the fields of geological disaster warning, groundwater resource management, oil and gas development, etc. In the existing technology, the monitoring of underground fluid migration through ground measurement and traditional satellite positioning systems has the problems of insufficient accuracy and delayed data processing. In addition, the traditional methods are not adaptable to complex geological conditions during the inversion process, and it is difficult to accurately describe the underground fluid migration process. Therefore, there is an urgent need for a high-precision underground fluid migration inversion method that can adapt to complex geological conditions.

[0003] With the development of global satellite navigation technology, especially the widespread application of the BeiDou Satellite Navigation System (BDS) independently developed by China, new technical means have been provided for the monitoring and analysis of underground fluid migration. The BeiDou satellite system has the advantages of wide coverage, high positioning accuracy, and strong real-time performance. The use of BeiDou satellites can overcome the shortcomings of traditional monitoring methods. By combining surface and underground sensors, high-precision monitoring and analysis of underground fluid migration can be achieved.

[0004] The finite element method is a mature numerical calculation method that is widely used in engineering analysis and scientific computing. By dividing the continuous medium into discrete finite elements, the finite element method can efficiently solve the distribution and changes of physical quantities in complex areas. Combined with the high-precision surface displacement data of the Beidou satellite, the finite element method can accurately simulate and invert the migration process of underground fluids.

[0005] Chinese patent CN104239406B discloses a groundwater monitoring method and system based on the global navigation satellite system (GNSS). The system includes multiple GNSS monitoring stations deployed in the monitoring area, and uses GNSS satellite positioning data combined with geological models and hydrological models to accurately monitor the dynamic changes of groundwater through inversion algorithms. The method uses GNSS high-precision positioning data to monitor surface deformation, thereby indirectly inferring groundwater level changes, and simulates and predicts groundwater migration based on this data. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a precise inversion method and system for underground fluid migration based on Beidou satellite observation.

[0007] The system of the present invention comprises a storage unit, a preprocessing unit, a computing unit and a sensing unit.

[0008] The storage unit stores radar images transmitted by Beidou satellites and stratum information obtained from geological exploration; The preprocessing unit preprocesses the radar images transmitted from the Beidou satellite and the stratum information obtained by geological exploration in the storage unit to generate a digital elevation model; The calculation unit uses the digital elevation model as an analysis model, uses a finite element method to accurately calculate the displacement of the target stratum, and generates corresponding results and cloud maps; The sensing unit determines the migration of underground fluid according to the target stratum displacement in the storage unit, and generates corresponding results and cloud maps.

[0009] The method of the present invention comprises the following steps: Step 1: Use Beidou satellite to obtain surface elevation; Step 2: Use geological exploration to obtain geological data and generate a digital elevation model; Step 3, accurately calculating the displacement of the target stratum according to the actual displacement of the surface; Step 4: Determine the migration of underground fluids based on the displacement of the target formation.

[0010] The beneficial effects of the present invention are as follows: the present invention obtains stratum information through geological exploration means, uses Beidou satellites to obtain surface radar images, combines surface displacement monitoring technology, and uses the finite element method in the system to accurately solve the digital elevation model, thereby achieving accurate acquisition of underground fluid migration conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A flow chart of a method for accurate inversion of underground fluid based on Beidou satellite observation according to the present invention; Figure 2 This is a composition diagram of the underground fluid precise inversion system based on Beidou satellite observation of the present invention; Figure 3 A flow chart for obtaining surface elevation using BeiDou satellites; Figure 4 Flowchart for generating digital elevation models for obtaining geological data using geological exploration; Figure 5 It is a schematic diagram of the location of the surface, various intermediate strata and target strata; Figure 6 A flow chart for the calculation unit to accurately calculate the displacement of the target stratum based on the actual displacement of the surface; Figure 7 Flowchart for determining target formation plume migration for the sensing unit; Figure 8 Schematic diagram of underground fluid migration under injection and production conditions. DETAILED DESCRIPTION

[0012] The present invention will be further described below with reference to the embodiments.

[0013] The main technical concept of the present invention is as follows: the underground fluid precise inversion system of the present invention mainly includes a storage unit, a preprocessing unit, a computing unit and a sensing unit. After the Beidou satellite acquires the surface radar image, the image is transmitted to the system, and the system preprocesses the image to eliminate interference factors such as atmospheric effect and terrain effect, and obtains the surface elevation data. The lithology information of each stratum is acquired by means of geological exploration, and the stratum information is stored in the storage unit of the system. The system establishes a digital elevation model based on the surface elevation information and the stratum information. Based on the digital elevation model, the system uses the finite element method to accurately solve the displacement of each stratum and generate corresponding results and cloud maps. According to the displacement of the target stratum, the sensing unit determines the migration of the underground fluid and finally generates a cloud map of the migration of the underground fluid. The present invention uses Beidou satellite monitoring surface technology to accurately determine the migration of underground fluids by monitoring the surface displacement, aiming to further improve the accuracy of sensing the migration of underground fluids.

[0014] like Figure 1 As shown, the main steps of the underground fluid accurate inversion method based on Beidou satellite observation in this application include the following: Use Beidou satellite to obtain surface elevation; Using geological surveys to obtain geological data, the system generates digital elevation models; Accurately calculate the displacement of the target stratum based on the actual displacement of the surface; The migration of underground fluids is determined based on the displacement of the target formation.

[0015] like Figure 2 As shown, the underground fluid precise inversion system based on Beidou satellite observation of the present application includes a storage unit, a preprocessing unit, a computing unit and a sensing unit.

[0016] The Beidou satellite can obtain radar images of a specified area at different times and send them to the system. At the same time, it can obtain the stratigraphic information of the area through geological exploration, and the stratigraphic information is stored in the system.

[0017] The storage unit stores radar images transmitted by Beidou satellites, stratigraphic information obtained from geological exploration, corresponding results and cloud maps preprocessed by the preprocessing unit, corresponding results and cloud maps calculated by the calculation unit, and corresponding results and cloud maps processed by the perception unit.

[0018] The preprocessing unit preprocesses the radar images transmitted by the Beidou satellite and the stratigraphic information obtained by geological exploration in the storage unit to generate a digital elevation model; the preprocessing unit includes a surface elevation processing module and a stratigraphic information processing module. The stratigraphic information processing module is used to import stratigraphic information and process the stratigraphic information into physical information required by the subsequent finite element model.

[0019] The calculation unit uses the digital elevation model in the storage unit as the analysis model, utilizes the finite element method to accurately calculate the displacement of the target stratum, and generates corresponding results and cloud maps.

[0020] The sensing unit determines the migration of underground fluid according to the target stratum displacement in the storage unit, and generates corresponding results and cloud maps.

[0021] In one example, Figure 3 As shown in the figure, in the process of using Beidou satellite to obtain surface elevation, the main steps include the following: Acquire radar images: The system receives radar images of the designated area at different times from Beidou satellites and stores them in the storage unit.

[0022] Generate interference map: The surface elevation processing module performs interference processing on radar images of the specified area at different times to generate an interference map, and stores it in the storage unit; the interference map mainly reflects surface deformation, terrain effect and atmospheric effect.

[0023] Eliminating terrain effects: The surface elevation processing module generates a reference interference map, differentiates it from the original interference map, obtains a differential interference map, and stores it in a storage unit; the differential interference map mainly reflects surface deformation and atmospheric effects.

[0024] Eliminate atmospheric effects; the surface elevation processing module uses time series analysis to eliminate the influence of atmospheric effects, generate a net surface deformation map, and store it in a storage unit.

[0025] The surface elevation is obtained; the surface elevation processing module performs phase unwrapping on the net surface deformation map, converts it into surface elevation information, and stores it in the storage unit.

[0026] In one example, Figure 4 As shown, in the process of using geological exploration to obtain geological data and systematically generating a digital elevation model, the main steps include the following: Determine the thickness and sequence of the strata; use drilling technology to determine the interface position of each stratum and measure the thickness of each stratum; use logging technology to perform auxiliary measurements to obtain accurate stratum thickness and sequence.

[0027] Determine hydrogeological parameters; obtain the location, thickness and permeability of aquifers and impermeable layers, etc.

[0028] Obtain lithology information of each stratum; determine lithology information of each stratum through drilling technology, such as rock type, mineral composition, porosity and permeability, etc.

[0029] The system generates a digital elevation model based on the actual surface elevation.

[0030] like Figure 5 As shown in the figure, the schematic diagram briefly illustrates the relative positions of the surface, the intermediate strata, and the target strata in three-dimensional space; the target strata contain underground fluids and exist in a flowing state; the actual displacement of the surface will change with the vertical displacement of the target strata. The top surface is the surface, the blue part is the target stratum, and the entire space is divided into grids for accurate finite element solutions.

[0031] In one example, Figure 6 As shown, the calculation unit accurately calculates the displacement of the target stratum according to the actual displacement of the surface, including the following steps: Data preprocessing: taking the digital elevation model as the processing object, coordinate conversion, error correction and data filtering are performed to eliminate systematic errors in the calculation process.

[0032] Meshing and model building: Meshing the underground medium area and building the geometric model and physical model required for finite element analysis.

[0033] Establish finite element equations; solve the displacement of the target stratum based on the actual surface elevation and the lithology data of the intermediate strata, and establish finite element equations.

[0034] Setting boundary conditions and initial conditions; setting boundary conditions and initial conditions of the finite element model.

[0035] Inversion solution: Solve the finite element equation of the target stratum displacement to obtain the actual displacement of the target stratum in three-dimensional space.

[0036] Generate corresponding results; form a displacement cloud map of the target stratum according to the displacement amount of the target stratum, and store it in the storage unit.

[0037] In one example, Figure 7 As shown, the sensing unit determines the migration of underground fluid according to the displacement of the target formation, including the following steps: The sensing unit obtains the displacement amount and displacement cloud map of the target stratum from the storage unit; The sensing unit determines the target stratum displacement mutation area based on the displacement amount of the continuous area combined with the displacement cloud map; The sensing unit determines the current plume spreading area based on the target stratum displacement mutation area; The sensing unit determines the plume migration situation based on the historical plume migration area situation, forms a plume migration cloud map, and stores it in the storage unit.

[0038] like Figure 8 As shown in the figure, the schematic diagram illustrates two migration situations of underground fluid in the target formation. The upper figure shows that after the fluid is injected into the target formation, the fluid migrates in the target formation, and the formation rises upward, causing the surface to rise; the lower figure shows that after the fluid is extracted from the target formation, the fluid migrates in the target formation, and the formation sinks downward, causing the surface to sink. The black arrow indicates the flow direction of the fluid, the dotted line indicates the diffusion range in different time periods (1 year and 10 years), and the horizontal line indicates the position of the formation.

Claims

1. An accurate inversion system for underground fluid migration based on BeiDou satellite observations, characterized in that: It includes a storage unit, a preprocessing unit, a computing unit and a sensing unit; The storage unit stores radar images transmitted by Beidou satellites and stratum information obtained from geological exploration; The preprocessing unit preprocesses the radar images transmitted from the Beidou satellite and the stratum information obtained by geological exploration in the storage unit to generate a digital elevation model; The calculation unit uses the digital elevation model as an analysis model, uses a finite element method to accurately calculate the displacement of the target stratum, and generates corresponding results and cloud maps; The sensing unit determines the migration of underground fluid according to the target stratum displacement in the storage unit, and generates corresponding results and cloud maps.

2. The precise inversion system for underground fluid migration based on Beidou satellite observation according to claim 1 is characterized in that: The BeiDou satellite acquires radar images of a designated area at different times and sends them to a precise inversion system.

3. The precise inversion system for underground fluid migration based on Beidou satellite observation according to claim 1, characterized in that: The preprocessing unit includes a surface elevation processing module and a stratum information processing module.

4. An accurate inversion method for underground fluid migration based on BeiDou satellite observations, characterized by The method comprises the following steps: Step 1: Use Beidou satellite to obtain surface elevation; Step 2: Use geological exploration to obtain geological data and generate a digital elevation model; Step 3, accurately calculating the displacement of the target stratum according to the actual displacement of the surface; Step 4: Determine the migration of underground fluids based on the displacement of the target formation.

5. The accurate inversion method for underground fluid migration based on Beidou satellite observation according to claim 4 is characterized in that: Step 1 specifically is: 1-1. Obtain radar images: The precise inversion system receives Beidou satellites to obtain radar images of the designated area at different times; 1-1. Generate interference map: The surface elevation processing module performs interference processing on radar images of the specified area at different times to generate interference map; 1-1. Eliminate terrain effect: The surface elevation processing module generates a reference interference map, which is differentiated from the original interference map to obtain a differential interference map; 1-1. Eliminate atmospheric effects; The surface elevation processing module uses time series analysis to eliminate the influence of atmospheric effects and generate a net surface deformation map; 1-5. Obtaining the surface elevation; the surface elevation processing module performs phase unwrapping on the net surface deformation map and converts it into surface elevation information.

6. The accurate inversion method for underground fluid migration based on Beidou satellite observation according to claim 4 is characterized in that: Step 2 is specifically: 2-1. Determine the thickness and sequence of the strata; use drilling technology to determine the interface position of each stratum and measure the thickness of each stratum; use logging technology to perform auxiliary measurements to obtain accurate stratum thickness and sequence; 2-2. Determine hydrogeological parameters; obtain the location, thickness and permeability of aquifers and aquicludes; 2-3. Obtain lithology information of each stratum; determine the lithology information of each stratum through drilling technology; 2-4. Generate a digital elevation model based on the actual surface elevation.

7. The accurate inversion method for underground fluid migration based on Beidou satellite observation according to claim 6 is characterized in that: The lithology information includes rock type, mineral composition, porosity and permeability.

8. The accurate inversion method for underground fluid migration based on Beidou satellite observation according to claim 4 is characterized in that: Step 3 specifically is: 3-1. Data preprocessing: Taking the digital elevation model as the processing object, coordinate conversion, error correction and data filtering are performed to eliminate the systematic errors in the calculation process; 3-2. Meshing and model construction: Meshing the underground medium area and constructing the geometric model and physical model required for finite element analysis; 3-3. Establish finite element equations; solve the displacement of the target stratum based on the actual surface elevation and the lithology data of the intermediate strata, and establish finite element equations; 3-4. Setting boundary conditions and initial conditions; Set the boundary conditions and initial conditions of the finite element model; 3-5. Inversion solution: Solve the finite element equation of the displacement of the target stratum to obtain the actual displacement of the target stratum in three-dimensional space; 3-6. Generate corresponding results; form a displacement cloud map of the target stratum according to the displacement amount of the target stratum.

9. The accurate inversion method for underground fluid migration based on Beidou satellite observation according to claim 4 is characterized in that: Step 4 is as follows: 4-1. Obtain the displacement amount and displacement cloud map of the target stratum; 4-2. Determine the target stratum displacement mutation area based on the displacement amount of the continuous area combined with the displacement cloud map; 4-3. Determine the current plume spreading area based on the target stratum displacement mutation area; 4-4. Determine the plume migration situation based on the historical plume migration area situation and form a plume migration cloud map.

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