Method and system for detecting diffusion radius of slurry in fracture network

Abstract

The invention discloses a method and a system for detecting the diffusion radius of slurry in a fracture network, and relates to the technical field of diffusion radius detection methods, and the method comprises the following steps: marking the flow velocity, the flow direction and the flow area of the slurry in a corresponding flow node based on analysis of each flow condition; in each flow node, the flow state of the slurry at the flow node is determined according to the flow speed, the flow direction and the flow area of the slurry, and the diffusion distribution diagram of the slurry is determined based on the flow state of the slurry at the flow node, the position of the flow node and the crack track, so that the accuracy of the diffusion distribution diagram of the slurry is improved. Therefore, the diffusion radius of the slurry is determined according to the diffusion area of the slurry at each flow node, the position of the flow node and the final flow position of the slurry, overall consideration of the diffusion area of the slurry at each flow node, the position of the flow node and the final flow position of the slurry is realized, and the detection accuracy of the diffusion radius of the slurry is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of methods for detecting diffusion radius, and in particular to a method and system for detecting the diffusion radius of slurry in a fracture network. Background Art

[0002] With the development of science and technology, slurry is a fluid material with fluidity, usually composed of a mixture of solid particles and liquid. The main component of slurry is liquid, usually water or other organic solvents. The liquid matrix provides the slurry with fluidity, enabling it to diffuse within the cracks. In existing technologies, the flow trajectory of the slurry is collected and the diffusion radius of the slurry is detected based on the flow trajectory. This does not take into account the flow conditions of the slurry at each flow node, affecting the accuracy of the slurry diffusion distribution map and resulting in low accuracy in the detection of the slurry diffusion radius. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art. The present invention provides a method and system for detecting the diffusion radius of slurry in a fracture network.

[0004] An embodiment of the present invention provides a method for detecting the diffusion radius of slurry in a fracture network, comprising: In the fracture network, the fracture distribution map is determined based on the detection of the rock mass, and the corresponding fracture trajectory is determined according to the identification of the fracture distribution map; When the slurry enters the rock mass, it flows along the fracture trajectory and marks the flow conditions of multiple flow nodes in the fracture trajectory. Based on the analysis of each flow condition, the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node are marked; At each flow node, the flow state of the slurry at the flow node is determined according to the flow velocity, flow direction, and flow area of ​​the slurry, and a diffusion distribution map of the slurry is determined based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; In the diffusion distribution diagram of the slurry, mark the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry; The diffusion radius of the slurry is determined according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry.

[0005] An embodiment of the present invention provides a system for detecting the diffusion radius of slurry in a fracture network. The system for detecting the diffusion radius of slurry in a fracture network is applied to the above-mentioned method for detecting the diffusion radius of slurry in a fracture network. The system for detecting the diffusion radius of slurry in a fracture network includes: A fracture trajectory module is used to determine the distribution map of fractures in the fracture network based on the detection of the rock mass, and to determine the corresponding fracture trajectory according to the identification of the fracture distribution map; An analysis module is used to analyze the flow of slurry along the fracture trajectory when the slurry enters the rock mass, mark the flow conditions of multiple flow nodes in the fracture trajectory, and mark the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node based on the analysis of each flow condition; a diffusion distribution map module for determining, in each flow node, the flow state of the slurry at the flow node according to the flow velocity, flow direction, and flow area of ​​the slurry, and determining a diffusion distribution map of the slurry based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; A marking module is used to mark the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry in the diffusion distribution diagram of the slurry; The diffusion radius module is used to determine the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry.

[0006] Compared with the prior art, the present invention has the following beneficial effects: In an embodiment of the present invention, through the method in the embodiment of the present invention, the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node are marked based on the analysis of each flow condition; in each flow node, the flow state of the slurry at the flow node is determined according to the flow velocity, flow direction and flow area of ​​the slurry, and the diffusion distribution map of the slurry is determined based on the flow state of the slurry at the flow node, the position of the flow node and the crack trajectory. The flow conditions of multiple flow nodes are introduced, and the overall consideration of the flow state of the slurry at the flow node, the position of the flow node and the crack trajectory is compatible, thereby improving the accuracy of the diffusion distribution map of the slurry.

[0007] Therefore, in the diffusion distribution diagram of the slurry, the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry are marked; the diffusion radius of the slurry is determined based on the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry, thereby realizing the overall consideration of the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry, and improving the detection accuracy of the diffusion radius of the slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 1 is a schematic flow chart of a method for detecting the diffusion radius of slurry in a fracture network according to an embodiment of the present invention; Figure 2 1 is a flow chart of step S11 in the method for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention; Figure 3 3 is a flow chart of step S12 in the method for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention; Figure 4 3 is a flow chart of step S13 in the method for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention; Figure 5 1 is a flow chart of step S14 in the method for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention; Figure 6 3 is a flow chart of step S15 in the method for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention; Figure 7 Schematic diagram of the structural composition of a system for detecting the diffusion radius of slurry in a fracture network in an embodiment of the present invention. DETAILED DESCRIPTION

[0009] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0010] See also Figures 1 to 7 A method for detecting the diffusion radius of slurry in a fracture network is applied to the detection scenario of the diffusion radius of slurry. The method for detecting the diffusion radius of slurry in a fracture network includes: Step S11: in the fracture network, a fracture distribution map is determined based on the detection of the rock mass, and corresponding fracture trajectories are determined according to the identification of the fracture distribution map; Step S12: When the slurry enters the rock mass, the slurry flows along the fracture trajectory, and the flow conditions of multiple flow nodes in the fracture trajectory are marked. Based on the analysis of each flow condition, the flow velocity, flow direction, and flow area of ​​the slurry at the corresponding flow node are marked; Step S13: In each flow node, the flow state of the slurry at the flow node is determined according to the flow velocity, flow direction, and flow area of ​​the slurry, and a diffusion distribution map of the slurry is determined based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; Step S14: marking the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry in the diffusion distribution diagram of the slurry; Step S15: determining the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node, and the final flow position of the slurry; refer to Figure 2 In step S11, the specific steps are: S111: collecting rock mass in the fracture network and performing real-time detection on the rock mass to output a fracture distribution map, determining multiple sub-fracture features based on the identification of the fracture distribution map, and marking the characteristic shapes and positions of the multiple sub-fracture features; S112: Determine the transition area between two adjacent sub-crack features based on the positions of multiple sub-crack features, determine the connected trajectory presented by the transition area based on the regional morphology of each transition area and the characteristic morphology of the corresponding two sub-crack features, determine the corresponding crack trajectory based on the synthesis of each connected trajectory, the characteristic morphology and positions of multiple sub-crack features, and present the crack trajectory in the crack distribution map.

[0011] In an embodiment of the present application, rock mass in a fracture network is collected and specific physical methods are used to detect fractures inside the rock mass. The method selected depends on the size and depth of the fractures, the characteristics of the rock mass itself, and the accuracy requirements of the detection. The detection process requires real-time data recording, that is, data collection and preliminary processing are carried out continuously to timely detect problems or adjust detection parameters. At the same time, geological radar (GPR) scanning or ultrasonic imaging is introduced.

[0012] For geological radar (GPR) scanning, the GPR antenna is placed close to the rock surface (such as the side of the core or the rock wall) for scanning. The GPR transmits electromagnetic waves, which reflect echoes when encountering interfaces with different dielectric constants (such as fracture surfaces, because the fractures contain air or water, which is different from the rock matrix). The receiver records the time and intensity of the echo. The GPR equipment can usually display a preliminary profile in real time, allowing the operator to observe whether there is a clear reflection signal (corresponding to the fracture). The resulting time-depth profile shows the strength and location of the reflection signal.

[0013] For ultrasonic imaging, an array of transmitters and receivers is placed on the surface of a rock core or block. Ultrasonic pulses are emitted, and the arrival time and energy attenuation of the sound waves along different paths through the rock mass are recorded. Cracks significantly increase the propagation time and attenuation of the sound waves. Modern ultrasonic testing systems can quickly calculate and display the distribution of wave velocity or attenuation, resulting in a two-dimensional or three-dimensional distribution of the sound wave velocity or attenuation. The original detection data usually contains noise and artifacts, and requires coordinate transformation and slicing processing to generate a clear crack distribution map. The goal of preprocessing is to enhance the crack signal, suppress noise, and convert the data into a format suitable for subsequent analysis (such as two-dimensional slice maps and three-dimensional volume data). At this time, filtering algorithms (such as median filtering and Gaussian filtering) are used to remove high-frequency noise or background interference, and contrast stretching, histogram equalization and other methods are used to highlight the crack characteristics. Ensure that the coordinate system of different scanning positions or different types of data (such as those combined with surface mapping) is consistent; reasonably fill in the data missing areas, and output one or more images / data sets to intuitively or numerically show the approximate location and morphology of the cracks in the rock mass. For example, on the GPR profile, the crack appears as a continuous strong reflection strip; in the ultrasonic map, it appears as a low-velocity area; in the ERT map, it appears as a high or low resistivity strip.

[0014] Cracks are separated from the background rock mass using methods such as threshold segmentation (setting an intensity or velocity threshold, and areas above / below the threshold are considered to be cracks), edge detection (such as the Canny operator, detecting edges with obvious brightness changes in the image), and region growing (starting from a seed point, merging adjacent areas with similar attributes). For each segmented crack area, its geometric features are calculated. For example, the minimum enclosing rectangle or convex hull is used to approximate the boundary of the crack, and its area, perimeter, length, width (short axis length), direction (long axis angle), etc. are calculated. A list of "sub-crack features" is then output, each of which is associated with its position in the image / data (such as the center coordinates (x, y, z)) and morphological parameters (such as length, width, direction).

[0015] The attribute information of the sub-crack features extracted in the previous step is recorded in a structured manner to form data that can be recognized and processed by computer programs, so that each sub-crack can be uniquely identified and referenced in subsequent analysis; the labels need to be standardized to ensure that the attributes of all sub-crack features are recorded in a unified manner; a database, structured array, or object list can be used for storage, and a sub-crack feature matching table is output, where each row / element represents a sub-crack feature and contains its ID, location coordinates, length, width, direction, and other fields; the sub-crack feature matching table is shown in Table 1.

[0016]

[0017] Furthermore, the transition area between two adjacent sub-crack features is determined according to the positions of multiple sub-crack features, the connected trajectory presented by the transition area is determined according to the regional morphology of each transition area and the characteristic morphology of the corresponding two sub-crack features, and the corresponding crack trajectory is determined according to the synthesis of each connected trajectory, the characteristic morphology and positions of multiple sub-crack features. The crack trajectory is presented in the crack distribution map, which is compatible with the overall consideration of the synthesis of each connected trajectory, the characteristic morphology and positions of multiple sub-crack features, thereby ensuring the accuracy of the corresponding crack trajectory.

[0018] At this time, the positions of multiple sub-crack features are introduced, and the positions of multiple sub-crack features are compared. At the same time, a spatial proximity analysis algorithm (such as based on a distance matrix or Voronoi diagram) can be used to identify potential adjacent sub-crack pairs; the transition area can be preliminarily defined as a line segment with the center points of the two sub-cracks as endpoints, or an area obtained by interpolation based on the edge morphology of the sub-cracks.

[0019] The regional morphology of each transition region and the characteristic morphology of the corresponding two sub-crack features are introduced. The characteristic morphology of the sub-crack features refers to the geometric properties of the sub-crack itself, such as direction, inclination, width, roughness, etc. The regional morphology of each transition region refers to the geometric shape of the transition region itself; at the same time, geometric analysis (such as calculating the angle between the characteristic direction vectors of the two sub-cracks, if the angle is too large, it is considered to be disconnected), morphological operations (such as dilation and erosion operations to simulate the connectivity of the channel), or more complex network analysis algorithms (such as Dijkstra algorithm to find the shortest connected path, considering morphological resistance) are used; the connected trajectory can be represented as a series of point coordinates, a line segment, or given certain attributes (such as connectivity probability, estimated width).

[0020] All confirmed connected trajectories are connected to the original sub-fracture features to form a complete, continuous fracture trajectory. A fracture trajectory consists of one or more sub-fracture features and one or more connected trajectories between them. At this time, graph theory methods can be used to treat sub-fracture features as nodes and connected trajectories as edges to construct a fracture network diagram. Continuous trajectories are then identified through path search algorithms (such as depth-first search (DFS) and breadth-first search (BFS). Geometric modeling tools (such as CAD software or GIS software) can also be used to manually or semi-automatically connect sub-fractures and connected trajectories. At the same time, the fracture trajectory is presented in the fracture distribution map, and the final determined fracture trajectory is superimposed or merged onto the originally generated fracture distribution map for intuitive viewing and analysis. At this time, the fracture trajectory (usually represented as a line or polygon) is plotted on a two-dimensional or three-dimensional fracture distribution map (including sub-fractures, rock mass background, etc.) using drawing software (such as Matplotlib, ParaView, ArcGIS, QGIS). Different colors or line types can be set to distinguish different fracture trajectories.

[0021] Optionally, assume that there is a two-dimensional core slice image (from S111's GPR or ultrasonic scanning). After processing by S111, the following two sub-fracture features (A1 and A2) are obtained: Sub-fracture feature A1: Position: center point coordinates (5.0 cm, 10.0 cm); shape: approximately horizontal, length 9.0 cm, width 0.5 cm, direction angle 0 degrees (horizontal to the right); Sub-fracture feature A2: Position: center point coordinates (5.0 cm, 20.0 cm); shape: approximately horizontal, length 8.0 cm, width 0.4 cm, direction angle 0 degrees (horizontal to the right).

[0022] Calculate the distance between the center points of A1 and A2: sqrt((5.0-5.0)²+(20.0-10.0)²)=10.0cm; assuming that the "adjacent" threshold is set to 1.5 times the maximum size of the sub-crack (A1 length 9cm, A2 length 8cm), that is, max(9,8) 1.5=13.5cm; because 10.0cm<13.5cm, A1 and A2 are considered to be adjacent; the transition area can be preliminarily defined as the vertical line segment connecting the center of A1 (5.0, 10.0) and the center of A2 (5.0, 20.0), or, considering the width of the sub-cracks, as a vertical strip area centered on this line segment and with a width equal to the average width of the two sub-cracks (about 0.45cm).

[0023] Check the morphology of the transition region (vertical line segment / band-shaped area) and the characteristic morphology of the two sub-cracks (both are horizontal); although the two sub-cracks are both horizontal, they are aligned in the vertical direction (same x-coordinate), and the transition region is vertical, which indicates that there is a continuous channel between them: extending horizontally for a while, then extending vertically upward for a while, and then extending horizontally again; therefore, it is determined that there is a connected trajectory, which can be represented as: from the right endpoint of A1 (14.0,10.0) > upward to (14.0,20.0) > to the right endpoint of A2 (14.0,20.0); or more simply, represented as a vertical line segment connecting the center points of A1 and A2, and marked as valid connection.

[0024] Now, combining sub-cracks A1 and A2, and the connecting trajectory (vertical line segment) between them, forms a complete crack trajectory, which consists of three parts: the horizontal part of A1, the vertical connecting part in the middle, and the horizontal part of A2. This trajectory can be represented as a series of continuous coordinate points, for example: (0.5, 10.0)>…>(14.0, 10.0)>(14.0, 20.0)>…>(13.0, 20.0).

[0025] Return to the original two-dimensional fracture distribution map (showing the rectangular areas A1 and A2, and the background of the rock mass); use drawing software to plot the complete fracture trajectory determined above (for example, represented by the thick blue line) on this map; the final map will clearly show that the two horizontal fracture areas (A1 and A2) are connected by a vertical line segment, forming a continuous fracture trajectory extending from the lower left to the upper right (or vice versa, depending on the fracture direction).

[0026] refer to Figure 3 In step S12, the specific steps are: S121: marking the fracture trajectory and the outer contour of the rock mass, and determining the injection port of the rock mass based on the matching of the fracture trajectory and the outer contour of the rock mass. The slurry enters the rock mass along the injection port and flows along the fracture trajectory. S122: In the fracture trajectory, multiple bending regions are determined based on autonomous identification of the fracture trajectory, and corresponding intersections are identified based on the detection of the multiple bending regions, and the intersections are used as flow nodes in the fracture trajectory. At this time, the fracture trajectory is marked with multiple flow nodes, each of which is passed by the slurry, and the flow conditions of each flow node are recorded; S123: Analyze the flow conditions of each flow node, and determine multiple parameters of the slurry at the corresponding flow node based on the analysis of the flow conditions of each flow node. At this time, the multiple parameters include flow velocity, flow direction, and flow area.

[0027] In an embodiment of the present application, the fracture trajectory is marked, and the continuous fracture trajectory (consisting of multiple sub-fracture features) identified in S11 is represented in a clear manner, which is usually done in a coordinate system (for example, a two-dimensional plane coordinate system xy or a three-dimensional coordinate system xyz); marking can be drawing lines on a digital map, or marking the path of the fracture on a physical model with colors, markers, etc.; the representation of the fracture trajectory needs to include its geometric information, such as the coordinates of the starting point, end point, and intermediate point, as well as the direction of the trajectory (which can be represented by angles or vectors).

[0028] Mark the outline of the rock mass. The outline of the rock mass refers to the boundary of the rock mass in space. Similarly, this outline also needs to be marked in the same coordinate system as the fracture trajectory. For two-dimensional cases, the outline is usually a closed polygon; for three-dimensional cases, it is a polyhedron or surface. The marking method can be drawing boundary lines, scanning the outline data point cloud, etc.

[0029] Placing the fracture trajectories and rock mass contours in the same spatial framework (coordinate system) ensures that the spatial relationship between them is accurate, just like drawing both the roads (fracture trajectories) and the boundaries of the map or specific areas (rock mass contours) on a map.

[0030] Alternatively, assume there is a laboratory square core sample with a side length of 10 cm. Through CT scanning and S11 processing, several major fractures in the core have been identified. One of the major fracture trajectories can be represented as a series of points: starting from (1,2), passing through (3,4), (5,5), (7,4), and ending at (9,2). The outer contour of the core is a square, whose boundaries are defined by the points (0,0), (10,0), (10,10), (0,10).

[0031] Marking process: On a 10cmx10cm coordinate paper, or in the drawing area of ​​a CAD / GIS software; use a red line segment to connect the points (1,2), (3,4), (5,5), (7,4), (9,2) in sequence. This is the marked fracture trajectory; use a black line segment to connect the points (0,0), (10,0), (10,10), (0,10) and back to (0,0). This is the marked rock mass outline. Now, there is a clear visual representation: within the boundary of a black square, there is a red fracture line that runs diagonally from the lower left to the upper right.

[0032] Find the intersection or contact point between the fracture trajectory and the rock mass contour; because the injection port must be a point on the rock mass surface (on the contour), and this point must be the starting point of the fracture trajectory or a point that can be directly connected to the fracture trajectory; the most direct case is that the starting point of the fracture trajectory is exactly on the rock mass contour; if the fracture trajectory is completely inside the rock mass, then the injection port is the point on the rock mass contour closest to this fracture trajectory, or it is necessary to artificially set a point on the contour as the entrance, and assume that the slurry can enter from here and connect to the nearest fracture; once a matching point is found, this point is defined as the injection port; it represents the physical entrance for the slurry to enter the fracture network inside the rock mass from the outside.

[0033] The slurry is pumped or poured into the rock surface through an injection port (a physical opening such as a drill hole, crack, or pre-set inlet). Since cracks are relatively weak and more permeable areas in the rock mass, the slurry will preferentially move along these connected channels (i.e., marked crack trajectories) rather than uniformly penetrating the entire rock matrix (unless the matrix is ​​also permeable). This process is affected by many factors, including the geometry of the cracks (width, roughness), the physical properties of the slurry (viscosity, density), and pressure differences.

[0034] Optionally, the injection port has been determined to be (1,0); a small hole is drilled at the (1,0) position of the core sample, which is the physical injection port; the configured slurry (such as a low-viscosity fluorescent liquid for subsequent observation) is injected from the hole (1,0) through a syringe or pump; it is observed that the slurry does not diffuse evenly into the core, but moves upward rapidly because there is a crack above; it first fills the small hypothetical vertical channel from (1,0) to (1,2) (if it exists), and then reaches the starting point of the crack (1,2); after reaching (1,2), the slurry begins to flow along the previously marked red crack trajectory: first moves to the upper right to (3,4), then continues to (5,5), then to (7,4), and finally to (9,2); during this flow process, the slurry mainly fills the space in the crack, and its front moves along the direction of the crack.

[0035] Furthermore, in the fracture trajectory, multiple bending areas are determined based on the autonomous identification of the fracture trajectory, and the corresponding intersections are identified based on the detection of multiple bending areas, and the intersections are used as flow nodes in the fracture trajectory. At this time, the fracture trajectory is marked with multiple flow nodes, each flow node is passed by the slurry, and the flow conditions of each flow node are recorded, which is compatible with the overall consideration of the autonomous identification of the fracture trajectory and ensures the accuracy of multiple bending areas.

[0036] At this time, the crack trajectory is introduced and the crack trajectory is autonomously identified. The bending area refers to the local area where the direction of the crack trajectory changes significantly, which usually corresponds to the place where the curvature of the trajectory changes greatly, or the place where the tangent direction of the trajectory changes significantly, thereby outputting the position information of the bending area, such as the coordinates of the center point of the area, or the range of trajectory segments covered by the area; optionally, the angle between adjacent segments on the trajectory is calculated, and an angle change threshold is set (for example, greater than 30 degrees or 45 degrees). The area near the connection point where the angle exceeds the threshold is the bending area.

[0037] Further analysis is performed on the bend area identified in the previous step; the focus is not on the bend itself, but whether the bend area intersects with other crack trajectories; Further analysis is performed on the bend area identified in the previous step; the focus is not on the bend itself, but whether the bend area intersects with other crack trajectories; Determine whether the bend area (or the trajectory segment near it) overlaps or is very close to other parts of the trajectory in spatial coordinates; Confirm that the overlapping or close parts do represent that the cracks are connected, rather than just overlapping in projection or very close but not connected; Optionally, geometric calculations can be used, such as line segment intersection algorithms, point and line segment distance calculations, etc.; For complex networks, more advanced graph theory algorithms are required to detect node connections; Clearly identify which bend areas are also intersections of crack trajectories, and record the precise coordinates of these intersections.

[0038] The intersections identified in the previous step are formally defined as "flow nodes". These nodes are considered to be key points on the slurry flow path because: flow direction changes: when the slurry reaches the intersection, it will choose to continue flowing in the original direction or turn into another fracture based on factors such as the width, roughness, and pressure of the fracture; flow resistance changes: the complex geometry of the intersection causes the local flow resistance to increase or decrease; flow velocity / flow distribution: if the intersection connects multiple fractures, the slurry flow will be distributed here.

[0039] The locations of these flow nodes are clearly marked on the digital or physical model of the fracture trajectory, for example, by using special symbols (such as circles or squares) on the digital map or by using a marker pen on the physical model; the fracture trajectory map now includes clearly marked flow nodes.

[0040] At the same time, in actual slurry injection experiments or simulations, the slurry will flow along the fracture trajectory and will inevitably pass through the previously defined flow nodes. This is based on the assumption of the connectivity of the fracture network. When the slurry front reaches each flow node, it is necessary to record the state of the node at that moment or the relevant flow information. The recording method depends on the monitoring method: Experimental monitoring: Measure at or near the node through sensors (such as pressure sensors, flow meters, optical markers), for example, record the time when the slurry arrives at the node, the instantaneous pressure at the node, the pressure difference before and after the node, etc.; Numerical simulation: The simulation software will automatically calculate and record the state of the slurry at the node, such as flow rate, flow direction, pressure, concentration, etc. Furthermore, it outputs a flow node record table, which lists the number and position of each flow node, as well as various monitoring data when the slurry passes through the node.

[0041] Alternatively, assume that there is a two-dimensional rock model with the following fracture trajectory (represented by points connected by line segments): starting point A(1,2)>B(3,4)>C(5,5)>D(7,4)>E(9,2)>F(9,0); and, assume that between points C and D, there is a fracture branch starting from G(6,3) and connecting to point D; so the complete trajectory contains the main trajectory ABCDEF and the branch GD.

[0042] Trajectory: AB segment goes to the upper right, BC segment continues to go to the upper right but the slope becomes gentler, CD segment goes to the lower right, DE segment continues to go to the lower right but the slope becomes gentler, and EF segment goes vertically downward; the direction at point B does not change much, point C changes from the upper right to the lower right, and the angle changes significantly (for example, more than 45 degrees); the direction at point D does not change much, point E changes from the lower right to vertically downward, and the angle changes significantly; points C and E are identified as bending areas; although C and E are not intersections, point D is the connection point between the main trajectory CDE and the branch GD, and is an intersection; point D is identified as an intersection.

[0043] Mark point D as a flow node. Although C and E are also inflection points, according to the description of this step, the "intersection" is mainly defined as a flow node. If the inflection point is also important, it can be supplemented in subsequent steps and only point D is defined as a flow node. On the trajectory diagram, point D is marked (for example, a circle is drawn). The slurry is injected from point A and flows along ABCDEF. When the slurry front reaches point D, the flow node record table is collected. The flow node record table is shown in Table 2:

[0044] Therefore, the flow conditions of each flow node are analyzed, and multiple parameters of the slurry at the corresponding flow node are determined based on the analysis of the flow conditions of each flow node. At this time, the multiple parameters include flow velocity, flow direction and flow area, which are compatible with the overall consideration of the analysis of the flow conditions of each flow node, ensuring the accuracy of multiple parameters of the slurry at the corresponding flow node.

[0045] At this time, the flow conditions of each flow node are collected, and the flow conditions of each flow node include: Time series data: such as the pressure and flow at the node changing with time; event records: such as when the slurry reaches the node and when it starts to diverge; state description: such as the connectivity state at the node (whether all branches are occupied by slurry); at the same time, the original recorded data is processed and interpreted to extract meaningful information, and the basic principles of fluid mechanics (such as conservation of mass, conservation of momentum, conservation of energy, or simplified Darcy's law, Bernoulli equation, etc.) are applied to the flow state at the node; the basic principles of fluid mechanics (such as conservation of mass, conservation of momentum, conservation of energy, or simplified Darcy's law, Bernoulli equation, etc.) are applied to the flow state at the node; based on the recorded data and The model infers the specific behavior of the slurry at the node, for example: flow distribution: if the node is a branch point, analyze the flow ratio of the mainstream and each branch; velocity change: analyze the velocity change of the slurry when approaching and leaving the node; pressure loss: calculate the pressure loss of the slurry when flowing through the node; filling situation: determine whether the crack space at the node has been completely or partially filled with slurry; the output of the analysis is an intermediate result, which provides a basis for calculating the final flow parameters (speed, direction, area). For example, the analysis shows that "at node D, the flow rate of the mainstream is 0.8L / min, flowing to E; the flow rate of branch GD is 0.2L / min, flowing to G; the pressure loss at the node is 0.3MPa".

[0046] The analytical results are combined with the geometric information at the nodes (from S11 and S12) to calculate the specific flow parameters; the flow parameters include: Flow Velocity: The speed of slurry movement in the fracture channel near the node. Calculation method: If the pressure difference Δp before and after the node D and the equivalent permeability k of the fracture section are known, combined with the viscosity μ of the slurry, Darcy's law v=(k / μ) can be used. (Δp / L), where L is the length of the crack; Flow Direction: The main direction of slurry movement at a node. Determination method: The path with the largest flow rate usually represents the mainstream direction. In the example of node D, the flow rate of 0.8 L / min toward E is much greater than the 0.2 L / min toward G, so the mainstream direction is C>D>E. Flow Area: The cross-sectional area of ​​the fracture that the slurry actually occupies or can flow at the node; Determination method: Based on morphological estimation: According to the characteristic morphology of the sub-fracture marked in S11 (such as width and height), assume a shape (such as a rectangular channel) and calculate its cross-sectional area. For example, if the main trajectory near node D is 0.5 cm wide and 0.3 cm high, then the area A = 0.5 cm 0.3cm=0.15cm².

[0047] refer to Figure 4 In step S13, the specific steps are: S131: At each flow node, a flow influence coefficient of the slurry is determined based on the matching between the position of the flow node and the type of the slurry, and a first sub-flow state coefficient is determined based on the flow velocity and flow direction of the slurry. S132: determining a second sub-flow state coefficient according to the flow velocity and flow area of ​​the slurry, and determining the flow state of the slurry at the flow node based on the first sub-flow state coefficient, the second sub-flow state coefficient, the flow influence coefficient of the slurry, and the flow state mapping relationship; S133: Collect the positions of the flow nodes, construct a first distribution map according to the positions of the flow nodes and the fracture trajectories, determine the diffusion distribution map of the slurry based on the synthesis of the first distribution map and the flow state of the slurry at each flow node, and present the diffusion traces of the slurry on the diffusion distribution map of the slurry.

[0048] In the embodiments of the present application, the position of the flow node and the type of slurry are collected. For the position of the flow node, the position of the flow node is not only the coordinates of the node (X, Y, Z), but more importantly, the geological environment and geometric characteristics in which it is located, such as: relative position: the distance from the rock boundary, free surface, impermeable layer (such as dense rock layer); geological structure: whether it is located in a fault zone, a joint-dense area, a stress concentration area, or a contact zone between different rock types; fracture geometry: the fracture width, roughness, and connectivity at the node (how many fractures intersect here).

[0049] Regarding the type of slurry, the type of slurry refers to the physical and chemical properties of the slurry itself, such as: rheological properties: viscosity (Newtonian fluid or non-Newtonian fluid, such as plastic viscosity, yield stress), density; particle properties: particle size distribution, shape; chemical properties: whether it contains additives (such as retarders, early strength agents, plasticizers), pH value, whether chemical reactions will occur; time dependence: changes in viscosity over time (such as thixotropy), setting time.

[0050] Establish association rules or calculation models between node location characteristics and slurry type characteristics. This model aims to quantify how this specific "location-slurry" combination affects the flow behavior of the slurry at the node. This can be based on: numerical simulation: use fluid mechanics software to simulate the flow under different conditions; through the above matching process, calculate the flow influence coefficient. This coefficient is a dimensionless value or a parameter with specific physical meaning. It represents the degree of correction or influence on the flow capacity of the slurry at the current node under the combined action of position and slurry type, so as to output a quantitative value, namely the flow influence coefficient (Flow Influence Coefficient, FIC). For example, FIC can be a value between 0 and 1, where 1 represents standard conditions (such as the node is located inside the rock mass and the slurry has standard viscosity), greater than 1 indicates a stronger promoting or hindering effect, and less than 1 indicates a weaker effect; alternatively, FIC can be a specific physical quantity, such as the corrected effective fracture width, permeability change factor, etc.

[0051] The flow velocity and flow direction of the slurry are introduced. The flow velocity of the slurry (V) is the average flow velocity or maximum flow velocity of the slurry measured or calculated at the flow node (unit: m / s, cm / s, etc.); the flow direction of the slurry (D) is the main movement direction of the slurry at the flow node, which can be an angle (relative to a reference direction, such as the X-axis) or a description (such as "flowing along crack A to node B", "dispersing in multiple directions at the node").

[0052] For the first sub-flow state coefficient, the influence of speed and direction is combined to calculate a first sub-flow state coefficient (FSSC1). This coefficient is intended to quantify the parameters that are determined by speed and direction and reflect the movement trend and kinetic energy state of the slurry at the node; the calculation method can be: FSSC1=w1 f(V)+w2 g(D), where f(V) is a function of velocity (such as V itself, or V squared), g(D) is a function of the degree of directional change or dispersion (such as the turning angle, or the number of branches), and w1 and w2 are weights; the output is a quantitative value, namely the first sub-flow state coefficient (FSSC1), which can reflect the overall motion state of the slurry at the node. For example, high FSSC1 indicates high-speed straight-line flow; medium FSSC1 indicates medium or low speed but obvious turning / dispersion; low FSSC1 indicates low-speed, stable flow (little directional change).

[0053] Optionally, determine the flow influence coefficient (FIC_A) for flow node A: Position matching: located inside the rock mass, but with three intersecting fractures (increasing complexity and promoting diffusion), and fractures 2 and 3 are narrow (hindering flow); Slurry matching: medium viscosity (medium resistance), containing retarders (delaying solidification, which is conducive to flow for a period of time); Taking all factors into consideration, the position of node A and the slurry characteristics cause the slurry to be both dispersed (promoting diffusion) and have a certain viscous resistance (hindering flow) at the node; assuming that through model or empirical judgment, FIC_A=0.8, this means that the comprehensive influence at this node is slightly lower than the standard condition.

[0054] Determine the first sub-flow state coefficient (FSSC1_A): Velocity (V_A): 0.5 cm / s, which is a medium to low flow velocity; Direction (D_A): The slurry undergoes significant turning and dispersion at node A; dispersion and turning usually increase FSSC1; assuming that FSSC1 = w1 V+w2 N_branch, and set w1=1, w2=2 (indicates more attention to direction changes), N_branch=2; FSSC1_A=1 0.5+2 2=4.5.

[0055] For the flow node B, the position matching is: close to the boundary (enhanced boundary effect, such as capillary action), located in the high stress area (stress changes the crack opening, usually reducing the opening and hindering flow); slurry matching: medium viscosity (medium resistance), containing retarder (delayed solidification, which is conducive to flow for a period of time); taking all factors into consideration, proximity to the boundary and high stress area are usually not conducive to slurry flow; assuming FIC_B=0.6, this means that the comprehensive influence at this node is significantly lower than the standard condition, and the flow is more easily hindered.

[0056] Determine the first sub-flow state coefficient (FSSC1_B): Velocity (V_B): 0.2 cm / s, which is a relatively low flow velocity; Direction (D_B): The slurry does not change much in direction at node B, and flows approximately in a straight line. Low velocity and stable direction usually result in a lower FSSC1; use the same schematic formula FSSC1=w1 V+w2 N_branch (assuming N_branch=1, indicating there is only one main path); FSSC1_B=1 0.2+2 1=2.2.

[0057] FIC_A=0.8 and FSSC1_A=4.5 were determined for flow node A, and FIC_B=0.6 and FSSC1_B=2.2 were determined for flow node B. These coefficients quantify the flow influence and initial state at each node, which are determined by the position, slurry type, speed and direction. Node A has a higher FSSC1 due to its dispersion and medium speed, indicating that its motion state is more active (although the speed is not particularly high). Node B has a lower FSSC1 due to its low speed and stable direction. The lower FIC of node B also indicates that its location environment is more unfavorable for flow. This information will be used in the subsequent step S132 to comprehensively determine the overall flow state of each node.

[0058] Furthermore, the second sub-flow state coefficient is determined according to the flow velocity and flow area of ​​the slurry, and the flow state of the slurry at the flow node is determined based on the first sub-flow state coefficient, the second sub-flow state coefficient, the flow influence coefficient of the slurry and the flow state mapping relationship, which is compatible with the overall consideration of the first sub-flow state coefficient, the second sub-flow state coefficient, the flow influence coefficient of the slurry and the flow state mapping relationship, and ensures the accuracy of the flow state of the slurry at the flow node.

[0059] At this time, the flow velocity and flow area of ​​the slurry are introduced. The flow velocity of the slurry (V) is determined from S123 and represents the instantaneous velocity of the slurry when passing through the node. The flow area of ​​the slurry (A) is also determined from S123 and represents the actual flow cross-sectional area occupied by the slurry when passing through the node. This area corresponds to the total cross-sectional area of ​​all fracture channels filled with slurry at the node. The purpose of FSSC2 is to quantify the “throughput capacity” or “blocking potential” of a slurry at a node; the flow velocity and the flow area together determine the instantaneous flow rate of the slurry (Q=V A), but FSSC2 focuses more on the relative relationship between speed and area or their combined impact; optionally, a two-dimensional lookup table of speed and area is established, and FSSC2 is searched according to the input (V, A).

[0060] The first sub-flow state coefficient (FSSC1), the second sub-flow state coefficient (FSSC2) and the flow influence coefficient (FIC) of the slurry were introduced. The first sub-flow state coefficient (FSSC1) comes from S131.2, reflecting the influence of speed and direction; the second sub-flow state coefficient (FSSC2) comes from S132.1, reflecting the influence of speed and area; the flow influence coefficient (FIC) of the slurry comes from S131.1, reflecting the influence of position and slurry type.

[0061] The flow state mapping is a key component that defines how to combine the three coefficients FSSC1, FSSC2, and FIC to map to a specific, descriptive flow state. This mapping can be: The flow state is determined based on the threshold combination of each coefficient. For example, if FIC>threshold and FSSC1<threshold and FSSC2<threshold, the state is "severely obstructed"; if FSSC1>threshold and FSSC2>threshold and FIC<threshold, the state is "rapid diffusion"; the values ​​of FSSC1, FSSC2, and FIC are substituted into the selected "flow state mapping relationship" to calculate the final flow state description and output the flow state (FSS) of the slurry at the flow node.

[0062] A comprehensive flow state is calculated for each flow node (in this example, nodes A and B are both determined to be "stable flow"). This state is the result of a comprehensive evaluation of multiple factors such as the velocity, direction, area, position, and slurry type at the node. This "flow state" will serve as important input information for constructing the diffusion distribution map in the next step S133. For example, for a node in the "significant diffusion" state, when constructing the diffusion map, it is necessary to consider the existence of a wider slurry distribution area around it.

[0063] Therefore, the positions of the flow nodes are collected, and a first distribution map is constructed according to the positions of the flow nodes and the fracture trajectories. The diffusion distribution map of the slurry is determined based on the synthesis of the first distribution map and the flow states of the slurry at each flow node, and the diffusion traces of the slurry are presented in the diffusion distribution map of the slurry. This is compatible with the overall consideration of the synthesis of the first distribution map and the flow states of the slurry at each flow node, thereby ensuring the accuracy of the diffusion distribution map of the slurry. At the same time, the flow conditions of multiple flow nodes are introduced, which is compatible with the overall consideration of the flow state of the slurry at the flow node, the position of the flow node and the fracture trajectory, thereby improving the accuracy of the diffusion distribution map of the slurry.

[0064] At this time, the precise coordinates (X, Y, Z) of each flow node have been determined from S122 or S131, for example, node A is at (2, 3, 1) and node B is at (5, 4, 1.5); construct the first distribution map: input the coordinate list of the flow nodes and the geometric information of the fracture trajectory connecting these nodes (and the endpoints of non-node fracture segments) (usually the starting point, end point, control point, etc. of the line segment or curve); draw the fracture trajectory in two-dimensional or three-dimensional space, usually represented by a line; at the same time, mark the flow nodes at the corresponding positions of the trajectory, which can be distinguished by different symbols (such as circles, squares) or colors, which is like drawing a "skeleton map" of the fracture network; the "first distribution map" is a basic map that includes the geometric morphology of the fracture network and the locations of key flow nodes; it itself does not contain the flow state information of the slurry, but only provides a blueprint of the "pipes" and "valves" (nodes) for the slurry flow.

[0065] Alternatively, assume that there is a fracture network on a two-dimensional plane, with the injection port at coordinate (0,0); flow node A at (2,3) and flow node B at (5,4); the fracture trajectory includes: a straight line segment from (0,0) to (2,3) (reaching node A); two paths branching out from (2,3): a straight line segment from (2,3) to (5,4) (reaching node B); a straight line segment from (2,3) to (3,5) (representing a branch); and a straight line segment extending from (5,4) to (7,5); construct a first distribution diagram, which is to draw these line segments on the two-dimensional plane and mark nodes A and B at (2,3) and (5,4). This diagram shows the path and key turning points of slurry flow.

[0066] The first distribution map and the flow state of the slurry at each flow node are introduced. The first distribution map contains a blueprint of the fracture network and the location of the flow nodes. The flow state of each flow node is obtained from S132, such as "stable flow", "significant diffusion", "blockage" and other qualitative or semi-quantitative states. In this example, nodes A and B are both "stable flow". The flow state information is superimposed or fused onto the first distribution map to reflect the actual distribution and diffusion of the slurry. It is necessary to predefine how different flow states are represented on the map. For example, "stable flow": a specific color (such as blue) is used at the node. Mark, and extend the color along the fracture trajectory segment where the node is located for a distance, indicating that the slurry flows steadily in this direction; the extension distance can be related to the velocity or flow area; "significant diffusion": mark the node with another color (such as red), and draw a semi-transparent area around the node (for example, represented by contour lines or color gradients) to indicate that the slurry diffuses from the node to the surrounding fractures; the size and shape of the area can be related to the diffusion coefficient or flow area; "blockage": use a special mark (such as a red cross) at the node, and indicate that the flow weakens or stops on its upstream trajectory segment.

[0067] According to the status of each node, it is drawn on the first distribution diagram. For example, for node A (stable flow), the blue color is extended along the (0,0)-(2,3) segment and the (2,3)-(5,4) segment; for node B (stable flow), the blue color is extended along the (2,3)-(5,4) segment and the (5,4)-(7,5) segment; if the node A status is "significant diffusion", a red semi-transparent circle will be drawn around the point (2,3); it is also possible to add status attributes to each node and edge in the data structure and record information about the diffusion area; the "slurry diffusion distribution map" is a richer visualization result, which not only shows the fracture network and nodes, but also intuitively demonstrates the flow characteristics, diffusion range and overall distribution pattern of the slurry at different locations.

[0068] The diffusion distribution map of the slurry shows the diffusion trace of the slurry, which includes not only the fracture paths that are clearly filled by the slurry (lines marked with colors), but also the translucent areas drawn around the "significant diffusion" nodes, as well as color gradients or contour lines to indicate the attenuation of the slurry concentration or influence; different colors, transparencies, line thicknesses or textures can be used to distinguish different flow states and diffusion degrees. For example, a thick blue line can be used for high-speed stable flow, a thin blue line for low-speed stable flow, and a red translucent fill for the "significant diffusion" area with a gradient edge; different colors, transparencies, line thicknesses or textures can be used to distinguish different flow states and diffusion degrees. For example, a thick blue line can be used for high-speed stable flow, a thin blue line for low-speed stable flow, and a red translucent fill for the "significant diffusion" area with a gradient edge.

[0069] The final "slurry diffusion distribution map" is an intuitive and information-rich image or data model. It integrates the geometric structure of the fracture network, the location of key nodes, and the flow state of the slurry at these nodes, thus clearly showing how the slurry flows and branches in the fracture network starting from the injection point, and where significant diffusion occurs. This map is an important basis for evaluating the slurry diffusion range, optimizing the grouting process, or analyzing the rock reinforcement effect.

[0070] Optionally, there are blue lines on the path from (0,0) to (2,3) to (5,4) to (7,5), indicating that the slurry flows steadily; there are also blue lines on the path from (2,3) to (3,5); there is a red, translucent, gradient-edged circle around point (3,5) (node ​​C), indicating that the slurry has significantly diffused from here; the figure is labeled, such as "injection port (0,0)", "node A", "node B", "node C", "stable flow path", "diffusion area", etc. This figure intuitively presents the "diffusion traces" of the slurry in the fracture network: it mainly flows along the main fracture channel, but at node C, there is obvious diffusion to the surrounding fractures.

[0071] By combining the positions of flow nodes (first distribution map) with their flow states (from S132), a visual slurry diffusion distribution map was generated. This process converted abstract parameters and states into intuitive spatial distribution information, allowing researchers to clearly see the movement trajectory and diffusion range of the slurry in the fracture network, providing key visual and data analysis support for the final determination of the diffusion radius.

[0072] refer to Figure 5 In step S14, the specific steps are: S141: monitoring the flow process of the slurry relative to the rock mass in real time, and recording the diffusion area and diffusion trace of the slurry at each flow node, and determining the diffusion coefficient of each flow node based on the diffusion area and diffusion trace of the slurry at each flow node; S142: sorting the diffusion coefficients of the flow nodes based on the flow sequence of the flow nodes, and determining the diffusion coefficient attenuation of two adjacent flow nodes based on the comparison of the diffusion coefficients of the flow nodes, where the diffusion coefficient attenuation is determined by comparing the diffusion coefficients of the two adjacent flow nodes; S143: Collect the current diffusion position of the slurry relative to the rock mass, determine the diffusible movement amount of the slurry based on the current diffusion position of the slurry relative to the rock mass, the diffusion coefficient of each flow node and the corresponding diffusion coefficient attenuation, and determine the final flow position of the slurry based on the current diffusion position of the slurry relative to the rock mass, the diffusible movement amount of the slurry and the current diffusion direction of the slurry.

[0073] In an embodiment of the present application, the movement trajectory, velocity change, and whether diffusion or blockage occurs in the rock mass fracture network after the slurry is injected from the injection port are continuously and dynamically observed; monitoring means: sensors are buried at key locations of the rock mass (such as near pre-selected flow nodes), for example.

[0074] Resistivity / conductivity sensor: The conductivity of slurry (especially cement-based slurry) is different from that of water. The passage of slurry will change the local conductivity, which can be detected. Acoustic sensor: The flow of slurry or filling of cracks will produce specific acoustic signals (such as friction sound and filling sound). The sensor can capture the changes in these signals. Pressure sensor: The flow of slurry will cause pressure changes. Monitoring pressure helps to judge the flow state. Temperature sensor: Some slurries (such as chemical slurries) will produce exothermic reactions when solidified. Temperature changes can indicate the slurry front. Fiber optic sensing (such as BOTDR / BOTDA): By measuring the changes in the backscattered or Raman scattering signals of light in the optical fiber, the strain and temperature along the optical fiber can be sensed with high precision. Alternatively, assume that grouting is being performed on the surrounding rock of a tunnel. Several key fracture intersections (flow nodes) are pre-identified in the rock mass, and resistivity sensors and acoustic sensors are buried near these nodes. When slurry is injected from the injection port (for example, node A), the system begins real-time monitoring. The resistivity sensor begins to record changes in conductivity, and the acoustic sensor captures the friction sound generated by the flow of slurry. The system records changes in these data over time. For example, the conductivity near node A begins to drop significantly 5 minutes after injection, and the acoustic intensity reaches a peak 8 minutes after injection and then gradually weakens, indicating that the slurry is passing through the node and diffusing outward.

[0075] The diffusion area and diffusion trace of the slurry at each flow node are recorded. The diffusion area refers to the two-dimensional (or three-dimensional) area covered by the slurry at a certain flow node, where, in addition to flowing along the main fracture channel, it also penetrates and diffuses into the surrounding smaller-scale fractures or pores. This usually occurs in areas such as nodes where fractures intersect and the space is relatively complex. The diffusion trace describes the specific pattern or direction preference of the slurry diffusion at the node, for example, whether it diffuses evenly in all directions or mainly diffuses along a specific small fracture direction, and whether the diffusion boundary is clear or fuzzy. This reflects the result of the combined effect of the local geological structure of the node and the slurry properties.

[0076] By analyzing data changes from the sensor network (such as the boundaries of resistivity changes and the distribution of acoustic wave energy), an inversion algorithm is used to estimate the diffusion range and pattern of the slurry. For example, the area where the resistivity decreases significantly can roughly define the diffusion area, and the direction of the largest resistivity gradient indicates the main diffusion direction. The observed diffusion area and trace are quantified. The diffusion area can be expressed in square centimeters (cm²) or square meters (m²). The diffusion trace can be described by a direction vector, a shape description (such as an elliptical or irregular shape), or the main diffusion angle range.

[0077] The diffusion area and diffusion trace of slurry at each flow node are introduced. The diffusion coefficient of each flow node is a dimensionless value or a value with a specific unit, which is used to quantify the "ability" or "tendency" of slurry to diffuse at a flow node. It comprehensively reflects the combined effect of the geological conditions at the node (such as the complexity, connectivity, and porosity of the fractures) and the slurry properties (such as viscosity and particle size). The larger the diffusion coefficient, the more likely the slurry is to diffuse significantly at the node. Optionally, the diffusion coefficient (DC) = k (Diffusion area / reference area)^α (1 Directional factor β); Among them, k, α, and β are constants to be calibrated, the reference area is a standard value (such as 1 cm²), and the directionality factor can be defined based on the number of main directions of the diffusion trace or the range of diffusion angles (for example, the completely isotropic diffusion factor is 0, and the completely unidirectional diffusion factor is 1). This formula or model needs to be calibrated using experimental data or field measurement data to determine the parameter values ​​so that the calculated results are consistent with the actual situation; for each flow node that records the diffusion area and trace, a corresponding diffusion coefficient value is calculated.

[0078] Furthermore, the diffusion coefficients of each flow node are sorted based on the flow sequence of each flow node, and the diffusion coefficient attenuation of two adjacent flow nodes is determined based on the comparison of the diffusion coefficients of each flow node. The diffusion coefficient attenuation is formed by the comparison of the diffusion coefficients of two adjacent flow nodes, which is compatible with the overall consideration of the comparison of the diffusion coefficients of each flow node, and ensures the accuracy of the diffusion coefficient attenuation of two adjacent flow nodes.

[0079] At this time, the flow sequence of each flow node is collected. This sequence is usually formed naturally during the real-time monitoring process. When the slurry reaches a new node, the node is recorded as the next flow node. For example, the slurry first reaches node A, then node B, and then node C, then the flow sequence is A>B>C.

[0080] Once all monitored flow nodes and their corresponding diffusion coefficients (such as DCA, DCB, and DCC calculated in the previous step S141) are determined, these diffusion coefficients can be arranged into a sequence according to the order in which they are actually reached by the slurry. This sequence reflects the changing trend of the diffusion capacity along the main flow path of the slurry. This order helps to identify areas with relatively strong or weak diffusion capacity. For example, if the diffusion coefficients of early nodes are generally higher, it means that the slurry is more likely to diffuse in the early stage of injection; if the diffusion coefficients of later nodes are lower, it means that the diffusion capacity of the slurry is weakened after penetrating into the rock mass.

[0081] In the sorted sequence, two nodes with consecutive positions are adjacent nodes. For example, in the sequence [DCA, DCB, DCC], nodes A and B are adjacent, and nodes B and C are adjacent. The diffusion coefficient attenuation refers to the difference between the diffusion coefficient of the previous node and the diffusion coefficient of the next node. It is usually calculated by subtracting the coefficient of the next node from the coefficient of the previous node, that is, the attenuation is the diffusion coefficient of the previous node - the diffusion coefficient of the next node. The diffusion coefficient attenuation quantifies the degree of weakening of the slurry diffusion ability when it is transferred from one node to the next adjacent node. A positive value indicates that the diffusion ability is indeed weakening, and a negative value indicates that the diffusion ability is increasing or there is a measurement error. The magnitude of the attenuation can help understand the influence of rock properties or fracture characteristics on slurry diffusion.

[0082] Therefore, the current diffusion position of the slurry relative to the rock mass is collected, and the diffusible movement amount of the slurry is determined according to the current diffusion position of the slurry relative to the rock mass, the diffusion coefficient of each flow node and the corresponding diffusion coefficient attenuation. The final flow position of the slurry is determined based on the current diffusion position of the slurry relative to the rock mass, the diffusible movement amount of the slurry and the current diffusion direction of the slurry. This is compatible with the overall consideration of the current diffusion position of the slurry relative to the rock mass, the diffusion coefficient of each flow node and the corresponding diffusion coefficient attenuation, thereby ensuring the accuracy of the diffusible movement amount of the slurry.

[0083] At this time, the current diffusion position of the slurry relative to the rock mass is collected, and the position of the slurry front is determined through a real-time monitoring system (such as a pressure sensor, flow meter, tracer concentration monitoring, or even video monitoring). For example, the end of the fracture segment where the pressure begins to drop significantly or the flow tends to stabilize is recorded, or the position where the tracer concentration reaches a certain threshold is recorded. This is the starting point for future predictions. The more accurate the position, the more reliable the subsequent predicted diffusible movement. Optionally, assume that during the monitoring process, it is recorded that the slurry front has just reached the position of node C. Accurately measure and record the three-dimensional coordinates of node C in the rock mass coordinate system, for example: C (X=5.2m, Y=3.1m, Z=1.8m). This is the current diffusion position.

[0084] The current diffusion position of the slurry relative to the rock mass, the diffusion coefficient of each flow node and the corresponding diffusion coefficient attenuation are introduced. The diffusible movement represents the maximum distance or range that the slurry can continue to move forward from the current diffusion position; it is not a fixed value, but is closely related to the residual energy of the slurry, the rock mass properties and the flow path; the diffusion coefficient (DC) reflects the potential for slurry diffusion at the node, while the attenuation (DCA) reflects the extent to which this potential is lost during the flow process; optionally, predictions can be made based on the attenuation of adjacent nodes; if the slurry reaches point C and is expected to flow to the next node D (assuming it exists), the attenuation from B to C (0.65) can be used to estimate the diffusion potential and subsequent attenuation of point C; if the attenuation tends to be stable or decreases, it means that the slurry can diffuse further; if the attenuation increases, the diffusion distance is limited. This quantity is directly related to how far the slurry can ultimately reach and is a key input for determining the "final flow position".

[0085] At the same time, the final flow position of the slurry is determined based on the current diffusion position of the slurry relative to the rock mass, the diffusible movement amount of the slurry and the current diffusion direction of the slurry; the current diffusion direction is usually determined by the flow direction determined in S122 and S123, especially the flow direction at the current node; it is a main direction and also a diffusion cone containing multiple directions.

[0086] Extend the diffusible movement amount along the current diffusion direction (or within the direction cone) to obtain the position or area where the slurry finally stops. This position is not necessarily a single point, but a small area, representing the final boundary of the slurry front; if the direction is single (for example, along the direction of the fracture CD), the final flow position is the point after moving the diffusible movement amount (0.29m) along the CD direction from the current point C; if the direction is diffuse (for example, node C connects multiple fractures), it is necessary to consider the main diffusion direction, or calculate the regional boundary formed after moving the diffusible movement amount in each direction.

[0087] By integrating the current diffusion position, the diffusion potential of the node (and its attenuation), and the flow direction, the future movement distance of the slurry is predicted (diffusible movement amount), and the expected "final flow position" of the slurry is finally determined. This process combines real-time monitoring data, historical flow information, and rock mass characteristic parameters, providing key endpoint information for subsequent steps (such as determining the diffusion radius in S11); in the above example, based on the position of node C, its diffusion coefficient, and the attenuation from the source point, it is predicted that the slurry can still move about 0.29 meters. Combined with the main flow direction, it is inferred that the final flow position of the slurry is approximately (5.44, 3.26, 1.8) meters. This position will be used to define the diffusion boundary of the slurry.

[0088] refer to Figure 6 In step S15, the specific steps are: S151: collecting the last flow position of the slurry, determining the diffusion area of ​​the slurry based on the synthesis of the last flow position of the slurry and the positions of each flow node, and marking the regional shape of the diffusion area of ​​the slurry; determining a first diffusion range of the slurry based on the regional shape of the diffusion area of ​​the slurry and the positions of each flow node; S152: determining a second diffusion range of the slurry according to the diffusion area of ​​each flow node and the position of each flow node, and determining a diffusion radius of the slurry based on a synthesis of the first diffusion range and the second diffusion range of the slurry; In an embodiment of the present application, the last flow position of the slurry is collected to obtain the precise position of the slurry at the current moment (or the final moment of the simulation) determined in step S14 (especially S143). This position is usually represented by three-dimensional coordinates (x, y, z), representing the spatial point where the slurry front or the last monitored flow node is located. The collection of this position depends on previous real-time monitoring data (such as sensor readings, image analysis results, etc.) and calculations (such as predictions in S143); ensuring the accuracy of this position is crucial for subsequent area definition.

[0089] The flow path of the slurry (formed by a series of flow nodes) and the final position of the slurry are combined to form a spatial "envelope" or "coverage" area. This area includes not only the fracture channels through which the slurry actually flows, but also the space occupied by diffusion at each flow node. It is not a simple line segment, but a geometric body with volume or area (depending on the dimension). Determining this area requires the use of spatial interpolation, polygon / polyhedron fitting, or simulation results based on diffusion models (such as permeability domains).

[0090] Optionally, all sequentially connected flow nodes (such as O>A>B>C) are connected into a main path; considering that the crack itself has a certain width, this main path can be given a width to form a "tubular" area; at each flow node, based on the previously recorded diffusion area or diffusion coefficient, the spatial range occupied by the slurry at the node is estimated (for example, it can be approximated as a sphere or ellipsoid with the node as the center and a radius equal to the equivalent diffusion radius); the above-mentioned "tubular" path and the "diffusion sphere / ellipsoid" of each node are merged to form a continuous, irregular geometric area, which represents the spatial range affected by the slurry in the rock mass.

[0091] After determining the geometry of the diffusion zone, a qualitative or semi-quantitative description is required, which helps to understand the spatial pattern of slurry diffusion, such as whether it extends along a single main fracture, is distributed in multiple branch fractures, or presents a certain symmetrical / asymmetric shape. This description can provide intuitive background information for subsequent engineering analysis. At this time, observe the synthesized diffusion zone graph (which can be a two-dimensional projection or a three-dimensional model) and use text or labels to describe its characteristics, such as: "extending linearly along the main fracture zone, with local expansion at the node", "presenting a dendritic distribution, mainly extending along two branch fractures", "approximately elliptical, with a denser central area", etc.

[0092] Based on the previously determined diffusion area morphology and node positions, a quantitative indicator that can represent the overall diffusion scale of the slurry is defined - the "first diffusion range". This indicator needs to be able to reflect the maximum spatial scale covered by the slurry from the starting point to the end point; since the diffusion area is usually irregular, the definition of the first diffusion range needs to be combined with the regional morphology; common methods include: path length plus node influence method: calculate the total length of the main path, and then add a correction value that reflects the influence of node diffusion (for example, take the average or maximum value of the equivalent diffusion radius of all nodes multiplied by a coefficient).

[0093] Furthermore, the second diffusion range of the slurry is determined based on the diffusion area of ​​each flow node and the position of each flow node, and the diffusion radius of the slurry is determined based on the synthesis of the first diffusion range and the second diffusion range of the slurry. This is compatible with the overall consideration of the synthesis of the first diffusion range and the second diffusion range of the slurry, ensuring the accuracy of the diffusion radius of the slurry. At the same time, it realizes the overall consideration of the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry, further improving the detection accuracy of the diffusion radius of the slurry.

[0094] At this point, the diffusion coefficient of each node has been calculated in S141, which indirectly reflects the diffusion area; now, it is necessary to use the diffusion area information of these nodes more directly; each flow node has a recorded diffusion area (for example, in the example of S141, node O: 5.0m², A: 3.92m², B: 2.8m², C: 1.6m²), this area represents the approximate size of the slurry spreading on the node and its nearby fracture surface; the node position information (coordinates) tells the specific spatial distribution of the slurry diffusion inside the rock mass.

[0095] Although the determination of the second diffusion range is mainly based on area, the location distribution of nodes will indirectly affect how to define this range. For example, if all nodes are concentrated in a small area, even if the individual area is large, the overall "range" is limited; conversely, if the nodes are dispersed, even if the individual area is not large, the overall coverage range is larger; there are many ways to determine the second diffusion range, the core idea is to "equivalent" the diffusion area of ​​each node to a range indicator that can represent the overall lateral diffusion degree; common methods include: weighted averaging of the equivalent radius according to the importance of the node on the path (such as flow rate, pressure, etc.); or, based on the location of all nodes and their diffusion area, calculating the radius / major axis of a minimum enclosing circle or ellipse that can cover all major diffusion areas.

[0096] The first diffusion range and second diffusion range of the slurry are introduced. The first diffusion range (R1): comes from S151, which more reflects the distance the slurry travels along the main path and the end position, combined with the influence of the node, and is a comprehensive linear scale (about 7.78 meters in the example); the second diffusion range (R2): comes from the first part of this step, which mainly reflects the maximum degree of lateral diffusion of the slurry at each node, and is a lateral scale (1.26 meters in the example).

[0097] Alternatively, a single indicator can simultaneously reflect the "depth" of the slurry along the path and the "breadth" of its lateral diffusion; directly taking R1 or R2 is not comprehensive enough; therefore, it is necessary to "synthesize" these two ranges; common methods include: weighted average method: R = α R1+(1-α) R2, where α is a weight coefficient between 0 and 1; the larger α is, the more the diffusion radius focuses on the path length; the smaller α is, the more emphasis is placed on lateral diffusion; the choice of α needs to be determined based on engineering experience or specific requirements.

[0098] Optionally, the first diffusion range R1≈7.78 meters; the second diffusion range R2=1.26 meters; the weighted average method is used to determine the final diffusion radius, and according to engineering experience, the importance of path length (R1) is 4 times that of lateral diffusion (R2); therefore, set α=0.8, (1-α)=0.2; calculate the diffusion radius: R=α R1+(1-α) R2, at this time, R=0.8 7.78+0.2 1.26; R≈6.22+0.25R≈6.47 m. This value takes into account both the longer distance the slurry travels along the main fracture channel (7.78 m) and the significant lateral diffusion occurring at the node (maximum equivalent radius 1.26 m). The weighted average (weighted toward path length) result (6.47 m) is slightly smaller than the first diffusion range, but much larger than the second diffusion range.

[0099] See also Figure 7 , Figure 7 Schematic diagram of the structure of a system for detecting the diffusion radius of slurry in a fracture network according to an embodiment of the present invention; the system for detecting the diffusion radius of slurry in a fracture network comprises: A fracture trajectory module 21 is used to determine a fracture distribution map in a fracture network based on detection of the rock mass, and to determine a corresponding fracture trajectory according to the identification of the fracture distribution map; The analysis module 22 is used to analyze the flow of the slurry along the fracture trajectory when the slurry enters the rock mass, mark the flow conditions of multiple flow nodes in the fracture trajectory, and mark the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node based on the analysis of each flow condition; a diffusion distribution diagram module 23 for determining, in each flow node, the flow state of the slurry at the flow node according to the flow velocity, flow direction, and flow area of ​​the slurry, and determining a diffusion distribution diagram of the slurry based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; a marking module 24 for marking the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry in the diffusion distribution diagram of the slurry; The diffusion radius module 25 is used to determine the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry.

[0100] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for detecting the diffusion radius of slurry in a fracture network, characterized in that: include: In the fracture network, the fracture distribution map is determined based on the detection of the rock mass, and the corresponding fracture trajectory is determined according to the identification of the fracture distribution map; When the slurry enters the rock mass, it flows along the fracture trajectory and marks the flow conditions of multiple flow nodes in the fracture trajectory. Based on the analysis of each flow condition, the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node are marked; At each flow node, the flow state of the slurry at the flow node is determined according to the flow velocity, flow direction, and flow area of ​​the slurry, and a diffusion distribution map of the slurry is determined based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; In the diffusion distribution diagram of the slurry, mark the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry; The diffusion radius of the slurry is determined according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry.

2. The method for detecting the diffusion radius of slurry in a fracture network according to claim 1, characterized in that: The method of determining a distribution map of cracks in a crack network based on detection of a rock mass and determining corresponding crack trajectories based on identification of the crack distribution map includes: Collect rock mass in the fracture network and perform real-time detection on the rock mass to output a fracture distribution map, determine multiple sub-fracture features based on the identification of the fracture distribution map, and mark the characteristic morphology and position of the multiple sub-fracture features; The transition area between two adjacent sub-crack features is determined according to the positions of multiple sub-crack features, the connected trajectory presented by the transition area is determined according to the regional morphology of each transition area and the characteristic morphology of the corresponding two sub-crack features, and the corresponding crack trajectory is determined according to the synthesis of each connected trajectory, the characteristic morphology and positions of multiple sub-crack features, and the crack trajectory is presented in the crack distribution map.

3. The method for detecting the diffusion radius of slurry in a fracture network according to claim 1, characterized in that: When the slurry enters the rock mass, the slurry flows along the fracture trajectory, and the flow conditions of multiple flow nodes in the fracture trajectory are marked. Based on the analysis of each flow condition, the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node are marked, including: Marking the fracture trajectory and the outer contour of the rock mass, and determining the injection port of the rock mass based on the matching of the fracture trajectory and the outer contour of the rock mass. The slurry enters the rock mass along the injection port and flows along the fracture trajectory. In the fracture trajectory, multiple bending regions are determined based on the autonomous identification of the fracture trajectory, and the corresponding intersections are identified based on the detection of multiple bending regions, and the intersections are used as flow nodes in the fracture trajectory. At this time, the fracture trajectory is marked with multiple flow nodes, each of which is passed by the slurry, and the flow conditions of each flow node are recorded; The flow conditions of each flow node are analyzed, and multiple parameters of the slurry at the corresponding flow node are determined based on the analysis of the flow conditions of each flow node. At this time, the multiple parameters include flow velocity, flow direction and flow area.

4. The method for detecting the diffusion radius of slurry in a fracture network according to claim 1, characterized in that: The method of determining the flow state of the slurry at each flow node according to the flow velocity, flow direction and flow area of ​​the slurry, and determining the diffusion distribution map of the slurry based on the flow state of the slurry at the flow node, the position of the flow node and the fracture trajectory, includes: At each flow node, the flow influence coefficient of the slurry is determined according to the matching between the position of the flow node and the type of the slurry, and at the same time, the first sub-flow state coefficient is determined according to the flow velocity and flow direction of the slurry; The second sub-flow state coefficient is determined according to the flow velocity and flow area of ​​the slurry, and the flow state of the slurry at the flow node is determined based on the first sub-flow state coefficient, the second sub-flow state coefficient, the flow influence coefficient of the slurry and the flow state mapping relationship.

5. The method for detecting the diffusion radius of slurry in a fracture network according to claim 4, characterized in that: The method further comprises: determining the flow state of the slurry at each flow node according to the flow velocity, flow direction and flow area of ​​the slurry, and determining the diffusion distribution map of the slurry based on the flow state of the slurry at the flow node, the position of the flow node and the fracture trajectory; The positions of the flow nodes are collected, and a first distribution map is constructed according to the positions of the flow nodes and the fracture trajectories. The diffusion distribution map of the slurry is determined based on the synthesis of the first distribution map and the flow state of the slurry at each flow node, and the diffusion traces of the slurry are presented in the diffusion distribution map of the slurry.

6. The method for detecting the diffusion radius of slurry in a fracture network according to claim 1, characterized in that: In the diffusion distribution diagram of the slurry, the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry are marked, including: Monitor the flow of slurry relative to the rock mass in real time, record the diffusion area and diffusion trace of the slurry at each flow node, and determine the diffusion coefficient of each flow node based on the diffusion area and diffusion trace of the slurry at each flow node; The diffusion coefficients of the flow nodes are sorted based on the flow sequence of the flow nodes, and the diffusion coefficient attenuation of two adjacent flow nodes is determined based on the comparison of the diffusion coefficients of the flow nodes. The diffusion coefficient attenuation is determined by comparing the diffusion coefficients of the two adjacent flow nodes.

7. The method for detecting the diffusion radius of slurry in a fracture network according to claim 6, characterized in that: The diffusion distribution diagram of the slurry marks the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry, and further includes: The current diffusion position of the slurry relative to the rock mass is collected, and the diffusible movement amount of the slurry is determined based on the current diffusion position of the slurry relative to the rock mass, the diffusion coefficient of each flow node and the corresponding diffusion coefficient attenuation. The final flow position of the slurry is determined based on the current diffusion position of the slurry relative to the rock mass, the diffusible movement amount of the slurry and the current diffusion direction of the slurry.

8. The method for detecting the diffusion radius of slurry in a fracture network according to claim 1, characterized in that: Determining the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node, and the final flow position of the slurry includes: The final flow position of the slurry is collected, the diffusion area of ​​the slurry is determined based on the synthesis of the final flow position of the slurry and the positions of each flow node, and the regional morphology of the diffusion area of ​​the slurry is marked; the first diffusion range of the slurry is determined based on the regional morphology of the diffusion area of ​​the slurry and the positions of each flow node.

9. The method for detecting the diffusion radius of slurry in a fracture network according to claim 8, characterized in that: The method of determining the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry further includes: The second diffusion range of the slurry is determined according to the diffusion area of ​​each flow node and the position of each flow node, and the diffusion radius of the slurry is determined based on the synthesis of the first diffusion range and the second diffusion range of the slurry.

10. A system for detecting the diffusion radius of slurry in a fracture network, characterized in that: The system for detecting the diffusion radius of slurry in a fracture network is applied to the method for detecting the diffusion radius of slurry in a fracture network as claimed in any one of claims 1 to 9, and the system for detecting the diffusion radius of slurry in a fracture network comprises: A fracture trajectory module is used to determine the distribution map of fractures in the fracture network based on the detection of the rock mass, and to determine the corresponding fracture trajectory according to the identification of the fracture distribution map; An analysis module is used to analyze the flow of slurry along the fracture trajectory when the slurry enters the rock mass, mark the flow conditions of multiple flow nodes in the fracture trajectory, and mark the flow velocity, flow direction and flow area of ​​the slurry at the corresponding flow node based on the analysis of each flow condition; a diffusion distribution map module for determining, in each flow node, the flow state of the slurry at the flow node according to the flow velocity, flow direction, and flow area of ​​the slurry, and determining a diffusion distribution map of the slurry based on the flow state of the slurry at the flow node, the position of the flow node, and the fracture trajectory; A marking module is used to mark the diffusion area of ​​the slurry at each flow node and the final flow position of the slurry in the diffusion distribution diagram of the slurry; The diffusion radius module is used to determine the diffusion radius of the slurry according to the diffusion area of ​​the slurry at each flow node, the position of the flow node and the final flow position of the slurry.

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