Oil reservoir well pattern streamline calculation method

Abstract

The invention belongs to the field of oil reservoir well pattern streamline calculation, and particularly relates to an oil reservoir well pattern streamline calculation method. The method comprises the steps of obtaining oil reservoir data, grouping fault data, creating polygon objects, combining polygons to form an integral polygon combination, constructing a spatial index structure to search for nearby points, calculating main flow lines and branch flow lines, considering the influence of faults at the same time, and extracting rule flow lines and thinning flow lines according to rules. According to the oil reservoir well pattern streamline calculation method based on the fault data, the complex form and distribution of the fault are fully considered, and the calculation precision and efficiency are improved.

Description

Technical Field

[0001] The invention belongs to the field of oil reservoir well pattern streamline calculation, and in particular relates to an oil reservoir well pattern streamline calculation method. Background Art

[0002] With the growing global demand for energy, oilfield development plays a vital role. In order to achieve efficient oil and gas production, accurate calculation of reservoir well network streamlines has become a key link. Reservoir well network streamlines refer to the fluid flow path between oil wells and water wells during oilfield development. It has a vital guiding significance for optimizing well network layout, improving oil and gas recovery, and formulating reasonable development strategies.

[0003] The traditional method for calculating the streamline of oil reservoir well pattern has achieved good results in many cases, but the shortcomings of the existing method for calculating the streamline of oil reservoir well pattern include the following aspects: (1) Insufficient ability to handle complex geological conditions: Existing technologies are often unable to cope with complex geological conditions, especially when faults are diverse and irregularly distributed. Faults, as fractures and dislocations of underground rocks, have a profound impact on the migration and accumulation of oil and gas. The complex morphology and distribution of faults make traditional calculation methods insufficient in terms of accuracy and efficiency.

[0004] (2) Lack of effective use of fault data: Existing technologies fail to fully consider the impact of faults on well network streamlines, resulting in inaccurate understanding of oil and gas flow patterns and certain limitations in the formulation of optimized development plans.

[0005] (3) The spatial index structure is not efficient enough: The existing spatial index structure has low query efficiency and accuracy when processing large-scale well network data, and cannot meet the high precision requirements of modern oilfield development.

[0006] (4) The streamline thinning method is not perfect: In the process of streamline thinning, the existing technology fails to effectively construct a unique streamline for the entire layer system, resulting in unclear streamline diagrams and affecting the formulation of development strategies.

[0007] As oilfield development continues to deepen, the requirements for the precision of reservoir description are getting higher and higher. It is necessary to consider the impact of faults on well network streamlines more accurately in order to better grasp the flow laws of oil and gas and optimize development plans. In addition, with the continuous development of computer technology and mathematical algorithms, new possibilities have been provided for solving complex reservoir well network streamline calculation problems. Therefore, developing a method and system that can efficiently and accurately calculate reservoir well network streamlines based on fault data has become a technical problem that needs to be solved urgently in the field of oilfield development. Summary of the invention

[0008] In view of the above technical problems, the present invention proposes a method for calculating streamlines in oil reservoir well patterns. The method includes obtaining well data and fault data, grouping fault data, creating polygon objects, merging these polygons to form an overall polygon combination, constructing a spatial index structure to find nearby points, calculating mainstream and branch streamlines, considering the influence of faults, and extracting regular streamlines and thinning streamlines according to rules.

[0009] The present invention is achieved through the following technical solutions: A method for calculating oil reservoir well pattern streamlines, the method comprising the following steps: (1) Read well data and fault data; (2) retaining the fault data within the coordinate range of the well data according to the coordinate range of the well data; (3) grouping the fault data filtered in step (2), combining the x-coordinates and y-coordinates corresponding to the same fault number into coordinate pairs, and converting the coordinate pairs of each fault into polygons, and creating a polygon combination containing all polygons; (4) Constructing spatial index structure; (5) Using the spatial index, calculate the distance between each oil well point and the adjacent water well point, and filter out the adjacent water well points within a specified range for each oil well point, or calculate the distance between each water well point and the adjacent oil well point, and filter out the adjacent oil well points within a specified range for each water well point; obtain the well layout pattern and well spacing range.

[0010] (6) Calculating the main flow line and the branch flow line according to the well layout and the well spacing range. During the calculation of the main flow line and the branch flow line, determine whether the main flow line and the branch flow line intersect, and exclude the intersecting part to obtain the global streamline without the influence of the fault; (7) The global streamlines obtained in step (6) are subjected to standardized screening to perform streamline thinning and construct a unique streamline for the entire layer system.

[0011] Further, in step (1), the well data includes the well number, the target layer abscissa, the target layer ordinate, and the well type; The slice data includes a slice number, an x ​​coordinate corresponding to each slice number, and a y coordinate corresponding to each slice number.

[0012] Further, step (2) is specifically as follows: filter the fault data and only retain the fault data whose x coordinate is within the range of [min_x, max_x] and whose y coordinate is within the range of [min_y, max_y]. Wherein, min_x is the minimum value of the horizontal coordinate of the target layer in the well data, and max_x is the maximum value of the horizontal coordinate of the target layer in the well data; min_y is the minimum value of the vertical coordinate of the target layer in the well data, and max_y is the maximum value of the vertical coordinate of the target layer in the well data.

[0013] Furthermore, step (3) is specifically as follows: The fault data filtered in step (2) are grouped according to the fault number, and the x-coordinate and y-coordinate corresponding to the same fault number are respectively combined into coordinate pairs. Based on the geometric principle, the coordinate pair of each fault is converted into a polygon object; According to the geometric method, all polygon objects corresponding to all faults are merged into an integral polygon combination containing all polygons.

[0014] Furthermore, an R-tree spatial index structure is used in step (4).

[0015] Furthermore, in step (5), when the well layout method adopted is the four-point method, the five-point method, the nine-point method, or the seven-point method, for each oil well point located in the polygon combination, the spatial index structure is used to query the nearby adjacent oil well points and adjacent water well points, the distance between each oil well point and the adjacent water well point is calculated, and the distance is compared with the preset distance range, and the adjacent water well points of each oil well point within the specified range are screened out to obtain the well layout method and the well spacing range; When the well layout method adopted is the inverse four-point method, the inverse seven-point method, or the inverse nine-point method, for each water well point located within the polygon combination, the spatial index structure is used to query nearby adjacent oil well points and adjacent water well points, and the distance between each water well point and the adjacent oil well point is calculated and compared with the preset distance range. The adjacent oil well points of each water well point within the specified range are screened out to obtain the well layout method and the well spacing range.

[0016] Furthermore, in step (6), the method for determining whether the main flow line and the branch flow line intersect is: Define the two points of the main flow line segment as and , the polygon formed by the flow dividing lines is expressed as ,in , represents a closed polygon; For line segments and the edges of polygon V , determine whether they intersect by calculating the intersection point: If the line segment If the intersection point of the line segment and the edge of the polygon is within the parameter range of the line segment and the edge, then they intersect. Let the line segment The parametric equation is: , ; in, , ; Sides of polygon V The parametric equation is: , ; in, , , ; If there exist t and s such that: ; Then the line segment and the edges of polygon V intersect.

[0017] Furthermore, in step (7), the standardized screening of the global streamlines is specifically performed as follows: Select the streamlines that meet the following two rules from the global streamlines as standard streamlines. The first rule is: the distance from the center point to the surrounding points meets the preset distance; The second rule is: use a contraction formula to reduce the area of ​​the closed graphic region formed by the surrounding points, excluding combinations where the center point is at the boundary of the closed graphic region and the distance from the center point to the surrounding points meets the preset distance; wherein the contraction formula is as follows: ; ; Among them, point Yes The coordinates after shrinkage, Yes With the previous point The angle between the line between and the positive x-axis is, ; The unit of contraction.

[0018] Beneficial technical effects of the present invention: The present invention proposes a method for calculating reservoir well pattern streamlines based on fault data, which fully considers the complex morphology and distribution of faults and improves the accuracy and efficiency of calculation.

[0019] The present invention adopts an efficient spatial index structure such as an R-tree, which can quickly search for nodes within a range, thereby improving query efficiency and accuracy.

[0020] The present invention supports a variety of well layout methods, can perform flexible calculations according to different well network layouts, and has stronger applicability.

[0021] The present invention introduces a method of streamline thinning and standardized screening, constructs a unique streamline for the entire layer system, makes the streamline diagram clearer, and facilitates the formulation of a reasonable development strategy.

[0022] The present invention fully considers the influence of faults when calculating the main flow line and the branch flow line, thereby ensuring the accuracy and reliability of the streamline calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for calculating a well pattern streamline in an oil reservoir according to an embodiment of the present invention; Figure 2 It is a global streamline diagram of the five-point method in an embodiment of the present invention; Figure 3 The five-point method standard streamline and global streamline diagram in the embodiment of the present invention; Figure 4 It is the standard streamline of the five-point method in the embodiment of the present invention; Figure 5 It is the streamline thinning by five-point method in the embodiment of the present invention; Figure 6 It is a global streamline diagram of the four-point method in an embodiment of the present invention; Figure 7 This is a streamline diagram thinned out using the four-point method in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. Those skilled in the art can fully understand the present invention without the description of these details.

[0026] An embodiment of a method for calculating a well pattern streamline in an oil reservoir, such as Figure 1 As shown, the method comprises the following steps: (1) Read well data and fault data; (2) retaining the fault data within the coordinate range of the well data according to the coordinate range of the well data; (3) grouping the fault data filtered in step (2), combining the x-coordinates and y-coordinates corresponding to the same fault number into coordinate pairs, and converting the coordinate pairs of each fault into polygons, and creating a polygon combination containing all polygons; (4) Constructing spatial index structure; (5) Using the spatial index, calculate the distance between each oil well point and the adjacent water well point, and filter out the adjacent water well points within a specified range for each oil well point, or calculate the distance between each water well point and the adjacent oil well point, and filter out the adjacent oil well points within a specified range for each water well point; obtain the well layout pattern and well spacing range.

[0027] (6) Calculating the main flow line and the branch flow line according to the well layout and the well spacing range. During the calculation of the main flow line and the branch flow line, determine whether the main flow line and the branch flow line intersect, and exclude the intersecting part to obtain the global streamline without the influence of the fault; (7) The global streamlines obtained in step (6) are subjected to standardized screening to perform streamline thinning and construct a unique streamline for the entire layer system.

[0028] In step (1) of the present invention, the well data includes the well number, the horizontal coordinate of the target layer, the vertical coordinate of the target layer, and the well type (oil well or water well); the fault data includes the fault number, the x coordinate corresponding to each fault number, and the y coordinate corresponding to each fault number.

[0029] Step (2) of the present invention is specifically as follows: filter the fault data and only retain the fault data whose x coordinate is within the range of [min_x, max_x] and whose y coordinate is within the range of [min_y, max_y]. Wherein min_x is the minimum value of the horizontal coordinate of the target layer in the well data, and max_x is the maximum value of the horizontal coordinate of the target layer in the well data; min_y is the minimum value of the vertical coordinate of the target layer in the well data, and max_y is the maximum value of the vertical coordinate of the target layer in the well data.

[0030] Step (3) of the present invention is specifically as follows: the fault data filtered in step (2) are grouped according to the fault number, the x coordinates and y coordinates corresponding to the same fault number are respectively combined into coordinate pairs, and based on the geometric principle, the coordinate pair of each fault is converted into a polygon object; specifically, for a group of fault coordinate pairs of the same fault, , forming a closed polygon by connecting these points; Based on the geometric method, all polygon objects corresponding to all faults are merged into a whole polygon combination. This process aims to comprehensively consider the influence range of multiple faults and form a complete regional representation.

[0031] In step (4) of the present invention, an R-tree spatial index structure is used. The present invention uses an R-tree to quickly search for nodes within a range. The core idea of ​​the R-tree is to aggregate nodes with similar distances and represent these points as their minimum circumscribed rectangles in the upper layer of the tree. The R-tree accepts a box to be searched, starts searching from the top layer, checks whether each bounding box in the tree intersects with the box to be searched, and continues searching in the sub-bounding boxes of the intersecting bounding boxes. The process is recursively performed until the object at the bottom layer is returned. The use of an efficient spatial index structure such as an R-tree can quickly search for nodes within a range, thereby improving query efficiency and accuracy.

[0032] In step (5), when the well layout method adopted is the four-point method, the five-point method, the nine-point method, or the seven-point method, for each oil well point located in the polygon combination, the spatial index structure is used to query the nearby adjacent oil well points and adjacent water well points, the distance between each oil well point and the adjacent water well point is calculated, and the distance is compared with the preset distance range, and the adjacent water well points of each oil well point within the specified range are screened out to obtain the well layout method and the well spacing range; When the well layout method adopted is the inverse four-point method, the inverse seven-point method, or the inverse nine-point method, for each water well point located within the polygon combination, the spatial index structure is used to query nearby adjacent oil well points and adjacent water well points, and the distance between each water well point and the adjacent oil well point is calculated and compared with the preset distance range. The adjacent oil well points of each water well point within the specified range are screened out to obtain the well layout method and the well spacing range.

[0033] In step (5), for each oil well point, the constructed spatial index structure is used to query the neighboring points (including oil wells and water wells) within the specified range. If the four-point rule is used, at least three or more nearest water well points are searched, which is generally 5, and the five-point rule is used to search for at least 4 or more nearest water well points, which is generally 6. Taking the four-point rule as an example, all combinations of three water well points are screened out through the five water well points, and the distance between the oil well point and each neighboring point is calculated and compared with the preset distance range to screen out the points within the specified range until all points in a certain combination meet the preset distance range. For the five-point rule, not only is it necessary to determine whether the distance from each water well point in the combination to the oil well point meets the preset distance, but the four points are also sorted and combined into a closed figure to determine whether the oil well point is within the closed figure (if it is the four-point rule, three surrounding points that meet the conditions must be found, and if it is the seven-point rule, six surrounding points that meet the conditions must be found). If the oil well point is not within the closed graph, this combination is excluded until a combination that meets the conditions is found. If none of them meet the conditions, the oil well point is placed in a special list and finally processed manually.

[0034] The ranking formula is as follows: ; in, for Points and Center Points The angle between the line and the positive x-axis. The point is a boundary point. For example, if the five-point method finds the four nearest well points as boundary points, the boundary points need to be sorted so that the lines connecting the boundary points form a closed quadrilateral figure instead of other crossed figures.

[0035] In step (6) of the present invention, when the well arrangement method adopted is the four-point method, the five-point method, the nine-point method or the seven-point method, the line connecting the water well point to the oil well point is called the main flow line, and the line connecting the closed figure formed by the water well points is called the diversion line; when the well arrangement method adopted is the reverse four-point method, the reverse seven-point method or the reverse nine-point method, the line connecting the oil well point to the water well point is called the main flow line, and the line connecting the closed figure formed by the oil well points is called the diversion line; The method for determining whether the main flow line and the branch flow line intersect is: Define the two points of the main flow line segment as and , the polygon formed by the flow dividing lines is expressed as ,in , represents a closed polygon; For line segments and the edges of polygon V , determine whether they intersect by calculating the intersection point: If the line segment If the intersection point of the line segment and the edge of the polygon is within the parameter range of the line segment and the edge, then they intersect. Let the line segment The parametric equation is: , ; in, , ; Sides of polygon V The parametric equation is: , ; in, , , ; If there exist t and s such that: ; Then the line segment and the edges of polygon V intersect.

[0036] In the present invention, the inverse four-point method and the inverse seven-point rule are used to find oil wells based on the water wells. In the calculation process, the influence of faults is also considered; the determination method is also whether the line segment and the polygon intersect, and finally the global streamline diagram is obtained.

[0037] In step (7) of the present invention, the standardized screening of the global streamlines is specifically as follows: Select the streamlines that meet the following two rules from the global streamlines as standard streamlines. The first rule is: the distance from the center point to the surrounding points meets the preset distance; specifically, the center point generally refers to an oil well, and the surrounding points are water wells, such as the positive four-point method and the positive five-point method; the inverse seven-point method is that the center point is a water well and the surrounding points are oil wells; the preset distance refers to a manually set parameter, such as the distance from the center point to the surrounding points. If the actual distance is greater than the preset distance, the current surrounding point is not a boundary point of the center point polygon; The second rule is: use the contraction formula to reduce the area of ​​the closed figure region formed by the surrounding points, excluding the combination where the center point is at the boundary of the closed figure region and the distance from the center point to the surrounding points meets the preset distance; the purpose of using the contraction formula is to remove the situation where the center point is at the edge of the closed figure.

[0038] The shrinkage formula is as follows: ; ; Among them, point Yes The coordinates after shrinkage, Yes With the previous point The angle between the line between and the positive x-axis is, ; The unit of contraction.

[0039] In step (7), the method of thinning out the streamlines is specifically as follows: the angles of all standard streamlines from oil wells to water wells are stratified to form a number of angle sets, and finally the median of the angle sets is taken to obtain the target angle, which is the final thinned streamline.

[0040] Specifically, even-numbered regular polygons can be deduplicated. For example, a quadrilateral originally has four streamlines corresponding to four angles, but two of the streamlines are repeated, so the two angles can be merged. For example, the five-point well network has four angles. All four angles are searched between 0 and 180 degrees, and then sorted according to the angles, combining the first and second angles, the third and fourth angles to obtain two angle sets; finally, the median of the angle set is taken to obtain two target angles, which are the final thinned streamlines; the effect is as follows: Figure 2-Figure 5 As shown, Figure 5 The two longest lines that intersect each other in the equation are the rarefaction streamlines.

[0041] Regular polygons with an odd number of points cannot be deduplicated. If it is a four-point rule, there are three angles, which are combined into three angle sets. Finally, the median of the three angle sets is taken to obtain the three target angles, which are the final thinned streamlines. Figure 6-Figure 7 The corresponding four-point normal streamlines and rarefied streamline diagrams are triangles with three angles.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating oil reservoir well pattern streamlines, characterized in that: The method comprises the following steps: (1) Read well data and fault data; (2) retaining the fault data within the coordinate range of the well data according to the coordinate range of the well data; (3) Grouping the fault data filtered in step (2), combining the x-coordinates and y-coordinates corresponding to the same fault number into coordinate pairs, and converting the coordinate pairs of each fault into polygons, creating a polygon combination containing all polygons; (4) Constructing spatial index structure; (5) Using the spatial index, calculate the distance between each oil well point and the adjacent water well point, and filter out the adjacent water well points within a specified range of each oil well point, or calculate the distance between each water well point and the adjacent oil well point, and filter out the adjacent oil well points within a specified range of each water well point; obtain the well layout method and well spacing range; (6) Calculating the main flow line and the branch flow line according to the well layout and the well spacing range. During the calculation of the main flow line and the branch flow line, determine whether the main flow line and the branch flow line intersect, and exclude the intersecting part to obtain the global streamline without the influence of the fault; (7) The global streamlines obtained in step (6) are subjected to standardized screening to perform streamline thinning and construct a unique streamline for the entire layer system.

2. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: In step (1), the well data includes the well number, the horizontal coordinate of the target layer, the vertical coordinate of the target layer, and the well type; The slice data includes a slice number, an x ​​coordinate corresponding to each slice number, and a y coordinate corresponding to each slice number.

3. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: Step (2) is as follows: filter the slice data and only retain the slice data whose x coordinate is within the range of [min_x, max_x] and whose y coordinate is within the range of [min_y, max_y]; Among them, min_x is the minimum value of the horizontal coordinate of the target layer in the well data, max_x is the maximum value of the horizontal coordinate of the target layer in the well data; min_y is the minimum value of the vertical coordinate of the target layer in the well data, and max_y is the maximum value of the vertical coordinate of the target layer in the well data.

4. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: Step (3) is as follows: The fault data filtered in step (2) are grouped according to the fault number, and the x-coordinate and y-coordinate corresponding to the same fault number are respectively combined into coordinate pairs. Based on the geometric principle, the coordinate pair of each fault is converted into a polygon object; According to the geometric method, all polygon objects corresponding to all faults are merged into an integral polygon combination containing all polygons.

5. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: In step (4), an R-tree spatial index structure is used.

6. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: In step (5), when the well layout method adopted is the four-point method, the five-point method, the nine-point method, or the seven-point method, for each oil well point located in the polygon combination, the spatial index structure is used to query the nearby adjacent oil well points and adjacent water well points, the distance between each oil well point and the adjacent water well point is calculated, and the distance is compared with the preset distance range, and the adjacent water well points of each oil well point within the specified range are screened out to obtain the well layout method and the well spacing range; When the well layout method adopted is the inverse four-point method, the inverse seven-point method, or the inverse nine-point method, for each water well point located within the polygon combination, the spatial index structure is used to query nearby adjacent oil well points and adjacent water well points, and the distance between each water well point and the adjacent oil well point is calculated and compared with the preset distance range. The adjacent oil well points of each water well point within the specified range are screened out to obtain the well layout method and the well spacing range.

7. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: In step (6), the method for determining whether the main flow line and the branch flow line intersect is: Define the two points of the main flow line segment as and , the polygon formed by the flow dividing lines is expressed as ,in , represents a closed polygon; For line segments and the edges of polygon V , determine whether they intersect by calculating the intersection point: If the line segment If the intersection point of the line segment and the edge of the polygon is within the parameter range of the line segment and the edge, then they intersect. Let the line segment The parametric equation is: ， ； in, , ; Sides of polygon V The parametric equation is: ， ； in, , , ; If there exist t and s such that: ； Then the line segment and the edges of polygon V intersect.

8. The method for calculating oil reservoir well pattern streamlines according to claim 1, characterized in that: In step (7), the standardized screening of the global streamlines is specifically as follows: Select the streamlines that meet the following two rules from the global streamlines as standard streamlines. The first rule is: the distance from the center point to the surrounding points meets the preset distance; The second rule is: use the contraction formula to reduce the area of ​​the closed graphic region formed by the surrounding points, excluding the combination where the center point is at the boundary of the closed graphic region and the distance from the center point to the surrounding points meets the preset distance; Wherein, the contraction formula is as follows: ； ； Among them, point Yes The coordinates after shrinkage, Yes With the previous point The angle between the line between and the positive x-axis is, ; The unit of contraction.

Images