River channel small layer porosity map drawing device and method

Abstract

The invention belongs to the technical field of oil and gas field development, and particularly relates to a river channel small layer porosity map drawing device and method. The method comprises the steps of firstly collecting well drilling single well data in an area and single sand body depth data in a target interval; according to the well drilling data and the single sand body depth data, inclined depth top and bottom depths and an average porosity value of the single sand body are extracted; calculating the average porosity value of the small-layer sand body according to the inclined depth top and bottom depths and the average porosity value of the single sand body; collecting a riverway contour map of a target interval, and drawing riverway boundaries according to the riverway contour map; and drawing a porosity graph based on the average porosity value of the small-layer sand body by taking the well data as a control point and the riverway boundary as a range. The method effectively solves the problem that the contour is not matched with the contour of the river channel when geologists describe the plait river small-layer porosity graph. Due to the characteristics of simplicity, practicability, accurate calculation result, high operability and the like, the method has important significance in high-development-degree and dense-well-pattern areas.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas field development, and particularly relates to an apparatus and method for drawing the porosity map of a small channel layer. Background Art

[0002] In recent years, tight gas has gradually attracted people's attention. However, due to the long diagenetic process of deep tight reservoirs, the rock debris components are in close contact, and most of the pores are filled with cementing materials, resulting in a reduction in pores and a generally poor pore structure, making research extremely difficult. Pores, as the space for storing oil and gas in reservoirs, their development degree determines the potential of reservoirs to store oil and gas, and greatly affects the development characteristics of "sweet spots" in tight sandstones. It is the focus of oil and gas exploration and development at home and abroad in recent years. In addition, during the development of gas fields, the encountered reservoirs are becoming more and more complex. Originally, adjacent wells encountered thick channel sand bodies, but now adjacent wells encounter inter-channel mudstones. This extremely fast phase change characteristic brings great challenges to well placement, especially the large-scale implementation of horizontal wells. The reason is that the spatial stacking law of channel sand bodies and reservoir physical properties have not been clarified. Therefore, during the process of oil and gas field development, there is an urgent need for a map that can reflect the adaptation between channels and porosity to guide the effective development of gas fields.

[0003] For example, the Chinese patent application document with the publication number CN115639126A discloses a method for calculating the porosity of a glutenite reservoir. It is proposed to establish a porosity model for the glutenite reservoir according to lithology categories, use the multiple linear regression method to establish a porosity calculation model, make full use of multiple logging information to optimize the logging response curves sensitive to porosity, and strengthen the concept of "lithology calibration logging technology" to overcome the dependence of the volume model on skeleton parameters. However, it does not consider the research method from point to surface, and problems such as the mismatch between the boundary of the reservoir physical property map and the geological channel contour may occur when drawing the porosity map in the later stage. Summary of the Invention

[0004] The purpose of the present invention is to provide an apparatus and method for drawing the porosity map of a small channel layer, so as to solve the problem that the contour of the porosity map of a braided river small layer drawn by geological personnel does not match the channel contour.

[0005] To solve the above technical problems, the present invention provides a method for drawing the porosity map of a small channel layer. First, collect the single-well data of the completed wells in the area and the depth data of single sand bodies in the target interval; according to the completed well data and the depth data of single sand bodies, extract the top, bottom depths and average porosity values of the single sand bodies; according to the top, bottom depths and average porosity values of the single sand bodies, calculate the average porosity value of the small layer sand bodies; collect the channel isoline map of the target interval, and outline the channel boundary according to the channel isoline map; based on the average porosity value of the small layer sand bodies, draw the porosity map with well data as control points and the channel boundary as the range.

[0006] The beneficial effects of the above technical solution are as follows: The present invention discovers that when there is a problem that the contour of the porosity map of a braided river sub-layer does not match the channel contour during the drawing of the porosity map by geological personnel, the problem of the mismatch between the contour of the porosity map and the channel contour can be solved by adding channel boundary data during the drawing of the porosity map. The present invention first collects the channel isoline map of the target interval to outline the channel boundary, and then uses the well data as control points and the channel boundary as the range to draw the porosity map. Therefore, the present invention is simple and practical, the calculation result is accurate, and the operability is strong, which is of great significance for areas with high development degree and dense well patterns.

[0007] Further, the steps for calculating the average porosity value of the sub-layer sand body in step 3) are as follows: First, calculate the length of a single sand body, which is the difference between the inclined bottom depth and the inclined top depth of the single sand body; then, use the length of each set of single sand bodies in each section of the target interval as the weight to perform weighted summation on the average porosity of the single sand body; finally, divide the result of the weighted summation by the sum of the lengths of each section of the single sand body to obtain the average porosity value of the sub-layer sand body.

[0008] The beneficial effects of the above technical solution are as follows: When calculating the average porosity value of the sub-layer sand body, the present invention calculates the length of each set of single sand bodies in each section. The length of a single sand body is equal to the difference between the inclined bottom depth and the inclined top depth. After accumulating the product results of the length of each set of single sand bodies in each section of the target interval and the average porosity of the single sand body and then dividing by the sum of the lengths of each section of the single sand body, the average porosity value of the sub-layer sand body is calculated more accurately, and the calculation process is simple.

[0009] Further, each section of the target interval refers to the single sand body section obtained by removing the ineffective reservoir by setting a minimum porosity value.

[0010] The beneficial effects of the above technical solution are that when calculating the average porosity of the sub-layer sand body, the present invention removes the single sand body section of the ineffective reservoir by setting a minimum porosity value, filters out the influence of the single sand body section of the ineffective reservoir on the calculation of the average porosity value of the sub-layer sand body, reduces the calculation error, and makes the calculation result accurate.

[0011] Further, outlining the channel boundary in step 4) means outlining the contour line according to the k-meter isoline outside the river in the target interval, where 0 ≤ k ≤ 20.

[0012] The beneficial effects of the above technical solution: The present invention outlines the contour line according to the k-meter isoline outside the river in the target interval, which can clearly and truly reflect the contour of the channel boundary.

[0013] Further, the completed well in step 1) refers to a completed well in which the vertical well section or the deviated well section penetrates the target interval and has logging data and stratigraphic correlation layering.

[0014] Beneficial effects of the above technical solution: The present invention draws a map for a completed well that penetrates the target layer in the vertical well section or inclined well section and has logging data and formation correlation stratification, which can reflect the distribution of the actual completed well, and improves the accuracy and effectiveness of the river channel small-scale porosity map.

[0015] Further, the single-well data in step 1) refers to data including well coordinates, elevation, trajectory, and curve data.

[0016] Beneficial effects of the above technical solution: The single-well data file in the present invention refers to a file including well coordinates, elevation, trajectory, and curve data. The data types in this file completely include the relevant data of the well, improving the accuracy and integrity of well drawing when drawing the porosity map.

[0017] Further, the single sand body depth data in step 1) refers to the vertical depth position and thickness data of each single-layer continuous reservoir determined based on core data and logging curves.

[0018] Beneficial effects of the above technical solution: The single sand body depth data in the present invention refers to the vertical depth position and thickness data of each single-layer continuous reservoir determined based on core data and logging curves. The data types in this file completely include the relevant data of the single sand body depth data, improving the accuracy of calculating the average porosity result for drawing the porosity map.

[0019] To solve the above technical problems, the present invention also provides a device for drawing a river channel small-layer porosity map, including a memory and a processor. The processor is used to execute computer program instructions stored in the memory to implement the method for drawing a river channel small-layer porosity map in any one of the above steps.

[0020] Beneficial effects of the above technical solution: This device mainly implements the method for drawing a river channel small-layer porosity map. The beneficial effects of the method for drawing a river channel small-layer porosity map have been discussed in the above steps and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flowchart of the method for drawing a braided river small-layer porosity map of the present invention;

[0022] Figure 2 is a well location map of a certain well area in the basin of the present invention;

[0023] Figure 3 is a logging curve map of the single sand body of the target layer He 1-3 section of Well X;

[0024] Figure 4 is a porosity map of the target layer He 1-3 section of a certain well area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Example of a method for drawing the porosity map of small layers in a river channel:

[0027] The overall process of this embodiment is as follows: As Figure 1 shown, collect the single-well data of the completed wells in the area and the depth data of single sand bodies in the target interval; according to the single-well data of the completed wells and the depth data of single sand bodies, extract the dip-top, dip-bottom depths and average porosity values of the single sand bodies; according to the dip-top, dip-bottom depths and average porosity values of the single sand bodies, calculate the average porosity value of the small-layer sand bodies; collect the river-channel isopach map of the target interval, and outline the river-channel boundary according to the river-channel isopach map. Taking the well data as control points and the river-channel boundary as the range, draw the porosity map of the small-layer sand bodies.

[0028] This embodiment is based on the Shiwen software for research, which is a relatively optimal implementation method, but not limited to this software only. Among them, the Shiwen software is a geological research platform for oil and gas exploration and development. The method steps for drawing the porosity map of small layers in a river channel of the present invention are as follows:

[0029] Step 1: Collect the single-well data of the completed wells in the area and the depth data of single sand bodies in the target interval;

[0030] Among them, the completed wells include the completed wells with the vertical well section or the deviated well section penetrating the target interval and having well logging data and stratigraphic correlation layering; the depth data of single sand bodies include the vertical depth position and thickness data of each single continuous reservoir determined by core data and well logging curves. The single-well data refers to the well coordinates, elevation, trajectory, and curve data. Save the single-well data in the format of the internal swi file of the Shiwen software (the swi file is a specific format file for the Shiwen software to manage the loaded single-well data, and this file is only applicable to the Shiwen software and does not support other software). Finally, load all the swi files of the completed wells in the area into the Shiwen library (the Shiwen library is the comprehensive management of geological data by the Shiwen software).

[0031] Step 2: According to the completed well data and the depth data of single sand bodies, extract the dip-top, dip-bottom depths and average porosity values of the single sand bodies;

[0032] Through the function of exporting sand body curve data in the Shiwen software, retrieve the dip-top, dip-bottom depths and average porosity values of the corresponding single sand bodies.

[0033] Step 3: According to the dip-top, dip-bottom depths and average porosity values of the single sand bodies, calculate the average porosity value of the small-layer sand bodies.

[0034] Calculate the average porosity value of small-layer sand bodies by means of macros in an Excel spreadsheet. The specific steps are as follows: ① Calculate the length of a single sand body, which is the difference between the inclined bottom depth and the inclined top depth of the single sand body; ② Set the minimum porosity value to remove invalid reservoir single sand body segments, generally setting the minimum porosity to 2 (%) ; ③ Use the length of each set of single sand bodies in each section of the target layer as the weight to perform a weighted sum of the average porosity of the single sand bodies, and divide the result of the weighted sum by the sum of the lengths of each section of the single sand bodies. The formula is as follows:

[0035] ω = φ 1 ×h 1 + φ 2 ×h 2 + ··· + φ n ×h n

[0036] φ = ω / (h 1 + h 2 + ··· h n )

[0037] In the formula: φ 1 is the average porosity of the single sand body in the first section of the target layer segment; h 1 is the length of the single sand body in the first section of the target layer segment; φ 2 is the average porosity of the single sand body in the second section of the target layer segment; h 2 is the length of the single sand body in the second section of the target layer segment; φ n is the average porosity of the single sand body in the nth section of the target layer segment; h n is the length of the single sand body in the nth section of the target layer segment; ω is the weighted combined calculation value; φ is the average porosity value of the reservoir in the target layer segment.

[0038] Step 4: Collect the channel contour map of the target layer segment and outline the channel boundary;

[0039] Consider the following factors: ① The mapping habit of geological maps, where the contour value is an integer; ② The porosity of reservoir rocks ranges from 1 to 40, and the effective value of k ranges from 0 ≤ k ≤ 20. Combining with the low-porosity and low-permeability physical properties of the study area, the porosity ranges from 1 to 18. Therefore, outlining the channel boundary means outlining the contour line according to the 2m contour line of the river in the target layer segment. The river in the target layer segment refers to the channel sand thickness map that conforms to the actual underground situation drawn by geological personnel through long-term geological research in this area.

[0040] Step 5: Based on the well data as control points and the channel boundary as the range, draw a porosity map based on the average porosity value of the small-layer sand bodies;

[0041] Among them, the porosity map is drawn by using Shuanghu software, with well data as control points and river channel boundaries as the scope, and the porosity map is drawn based on the average porosity value of the small layer sand body. The porosity map means that the porosity value at the well point position is plotted in accordance with the corresponding well data; the contour interval of the map is 2, and the interval is 1.

[0042] Taking a certain well area in a certain basin as an example, the present embodiment will be further described in detail below.

[0043] Among them, river channels are divided into braided rivers, meandering rivers, straight rivers, network rivers, seasonal rivers, etc. relatively speaking. The outlines of braided rivers, meandering rivers, and straight rivers are clear and easy to depict. Therefore, taking a certain well area in a certain basin and a braided river as an example, the present embodiment will be further described in detail below. Taking a certain well area in a certain basin as an example, there are 164 completed wells in the well area, such as Figure 2 . Since the efficient development, the geological understanding has been continuously deepened, and a fine contour map of the thickness of the braided river sand body has been drawn in the well area. On this basis, the porosity map of the target layer He 1-3 section is drawn by applying the method of the present invention.

[0044] Collect the single well data sorted out after the completion of the previous 164 single wells and the depth data of the single sand body within the target layer He 1-3 section.

[0045] According to the completed well data and the depth data of the single sand body, extract the top and bottom depths of the inclined depth of the single sand body and the average porosity value;

[0046] Taking Well X as an example, there are 5 sets of single sand bodies developed in the He 1-3 section. After running, the average porosity of the target layer He 1-3 section is 10.8%, as shown in Table 1, Figure 3 as shown.

[0047] Table 1 Statistical table of the average porosity of the He 1-3 section of Well X

[0048]

[0049] Taking the boundary of the braided river channel in the target layer He 1-3 section as the scope, and taking the average porosity calculated in the above steps of 164 wells as control points, draw a porosity map in professional software, as shown in Figure 4 as shown.

[0050] An embodiment of a device for drawing the porosity map of a small layer of a river channel:

[0051] An embodiment of a device for drawing a porosity map of a small layer of a river channel according to the present invention includes a memory, a processor, and an internal bus. The processor and the memory complete mutual communication and data interaction through the internal bus. The memory includes at least one software function module stored in the memory. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, and implements a method for a device for drawing a porosity map of a small layer of a river channel introduced in the method embodiment of the present invention. Among them, the processor can be a processing device such as a microprocessor MCU or a field programmable gate array FPGA. The memory can be various memories that store information in an electrical energy manner, such as RAM, ROM, etc.

Claims

1. A method for drawing the porosity map of small layers in a river channel, characterized in that: It includes the following steps: 1) Collect the single-well data of the completed wells in the area and the depth data of single sand bodies in the target interval; 2) According to the completed well data and the depth data of single sand bodies, extract the dip-top, bottom depth and average porosity value of the single sand body; 3) According to the dip-top, bottom depth and average porosity value of the single sand body, calculate the average porosity value of the small layer sand body; 4) Collect the river channel isoline map of the target interval, and outline the river channel boundary according to the river channel isoline map; 5) Taking the well data as control points and the river channel boundary as the range, draw the porosity map according to the average porosity value of the small layer sand body.

2. The method for drawing the porosity map of small layers in a river channel according to claim 1, characterized in that: The step of calculating the average porosity value of the small layer sand body in step 3) is to first calculate the length of the single sand body, and the length of the single sand body is the difference between the dip-bottom depth and the dip-top depth of the single sand body; then use the length of each set of single sand bodies in each section of the target interval as the weight to perform weighted summation on the average porosity of the single sand body; finally, divide the result of the weighted summation by the sum of the lengths of each section of the single sand body to obtain the average porosity value of the small layer sand body.

3. The method for drawing the porosity map of small layers in a river channel according to claim 2, characterized in that: The target interval refers to the single sand body section obtained by removing the ineffective reservoir by setting the minimum porosity value.

4. The method for drawing the porosity map of small layers in a river channel according to any one of claims 1 to 3, characterized in that: The outlining of the river channel boundary in step 4) refers to outlining the contour line according to the k-meter isoline outside the river in the target interval, where 0 ≤ k ≤ 20.

5. The method for drawing the porosity map of small layers in a river channel according to claim 1, characterized in that: The completed well in step 1) refers to a completed well in which the vertical well section or the deviated well section penetrates the target interval and has logging data and stratigraphic correlation layering.

6. The method for drawing the porosity map of small layers in a river channel according to claim 1, characterized in that, The single-well data in step 1) refers to data including well coordinates, elevation, trajectory and curves.

7. The method for drawing the porosity map of small layers in a river channel according to claim 1, characterized in that, The depth data of the single sand body in step 1) refers to the vertical depth position and thickness data of each single-layer continuous reservoir determined based on core data and logging curves.

8. A device for drawing the porosity map of small layers in a river channel, including a memory and a processor, characterized in that: The processor is used to execute the computer program instructions stored in the memory to implement the method for drawing the porosity map of small layers in a river channel according to any one of claims 1 to 7.

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