Cover layer breakthrough pressure prediction method and device

Abstract

The invention discloses a method and device for predicting the breakthrough pressure of a cap layer, and relates to the technical field of oil exploration and development, and the method comprises the steps: obtaining the breakthrough pressure of a rock core sample of a to-be-detected cap layer region; obtaining the breakthrough pressure of any measuring point in the to-be-measured cover layer area by utilizing the breakthrough pressure of the rock core sample and a preset conversion formula; the preset conversion formula reflects the relationship between the breakthrough pressure, the permeability and the porosity of any measuring point and the breakthrough pressure, the permeability and the porosity of the rock core sample; wherein the permeability and the porosity of any measuring point in the to-be-measured cover layer area and the permeability and the porosity of the rock core sample are known values. According to the method, the cap layer breakthrough pressure of any point of the to-be-measured cap layer area can be rapidly obtained in batches.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration and development technology, and in particular to a method and apparatus for predicting caprock breakthrough pressure. Background Technology

[0002] The sealing capacity of the caprock is a key parameter for evaluating the success or failure of underground natural gas storage facilities and reservoirs. However, how to easily evaluate the direct caprock capacity above the gas storage layer, especially the caprock breakthrough pressure over a large area, is a technical problem that has troubled researchers of large-scale underground gas storage.

[0003] Currently, the method for obtaining caprock breakthrough pressure comes from indoor physical simulation experiments. Specifically, this involves drilling core samples from the caprock and determining the breakthrough pressure of the samples according to existing industry standards. This method is characterized by its applicability to single core sampling points, the requirement of prior drilling and coring, and its long testing time. Furthermore, its testing efficiency is low when measuring caprock breakthrough pressure over a large area. Existing technologies also include methods for predicting caprock breakthrough pressure over large areas using multiple parameters such as well logging data, density, and porosity. However, these existing methods involve complex model building and have poor accuracy. Summary of the Invention

[0004] This invention provides a method for predicting caprock breakthrough pressure, which can quickly and in batches calculate the caprock breakthrough pressure over a large area, while improving the prediction accuracy of caprock breakthrough pressure. The method includes:

[0005] Obtain the breakthrough pressure of core samples from the caprock region to be tested;

[0006] Using the breakthrough pressure of the core sample and a preset conversion formula, the breakthrough pressure at any measuring point in the caprock region to be tested is obtained; the preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample; wherein, the permeability and porosity of any measuring point in the caprock region to be tested, and the permeability and porosity of the core sample are known values.

[0007] This invention also provides a device for predicting caprock breakthrough pressure, used to quickly and batch-calculate caprock breakthrough pressure over a large area, while improving the prediction accuracy of caprock breakthrough pressure. The device includes:

[0008] The sample testing module is used to obtain the breakthrough pressure of core samples from the caprock region to be tested;

[0009] The breakthrough pressure calculation module is used to obtain the breakthrough pressure at any measuring point in the caprock region to be tested using the breakthrough pressure of the core sample and a preset conversion formula. The preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample. The permeability and porosity of any measuring point in the caprock region to be tested, as well as the permeability and porosity of the core sample, are known values.

[0010] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described method for predicting caprock breakthrough pressure.

[0011] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for predicting caprock breakthrough pressure.

[0012] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described method for predicting caprock breakthrough pressure.

[0013] In this embodiment of the invention, the breakthrough pressure of a core sample from the caprock region to be tested is obtained. Using the breakthrough pressure of the core sample and a preset conversion formula, the breakthrough pressure at any measuring point in the caprock region to be tested is obtained. The preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample. The permeability and porosity of any measuring point in the caprock region to be tested, and the permeability and porosity of the core sample, are known values. Compared with existing technologies, this embodiment of the invention, when determining the breakthrough pressure of the caprock, only requires one acquisition and testing of the caprock core sample. It only needs to input the basic parameters of porosity and permeability at any point in the caprock to determine the breakthrough pressure at that point. This allows for the rapid acquisition of massive breakthrough pressure data of the study area in a short time, offering advantages such as speed, low workload, and theoretical support. It is suitable for rapid operational condition evaluation of the breakthrough pressure of caprocks in geological bodies such as gas reservoirs, gas storage facilities, and oil reservoirs, filling a gap in the industry for rapidly obtaining caprock breakthrough pressure fields. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0015] Figure 1 This is a flowchart illustrating the caprock breakthrough pressure prediction method in an embodiment of the present invention.

[0016] Figure 2 This is a diagram of a specific embodiment of the caprock breakthrough pressure prediction method in this invention;

[0017] Figure 3 This is a diagram of a specific embodiment of the caprock breakthrough pressure prediction method in this invention;

[0018] Figure 4 This is a schematic diagram of the caprock breakthrough pressure prediction device in an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0021] The acquisition, storage, use, and processing of data in this application all comply with the relevant provisions of national laws and regulations.

[0022] Currently, the method for obtaining caprock breakthrough pressure comes from indoor physical simulation experiments. Specifically, this involves drilling core samples from the caprock and determining the breakthrough pressure of the samples according to existing industry standards. This method is characterized by its applicability to single core sampling points, the requirement of prior drilling and coring, and its long testing time. Furthermore, its testing efficiency is low when measuring caprock breakthrough pressure over a large area. Existing technologies also include methods for predicting caprock breakthrough pressure over large areas using multiple parameters such as well logging data, density, and porosity. However, these existing methods involve complex model building and have poor accuracy.

[0023] To address the limitations of current methods for predicting caprock breakthrough pressure, this invention, through theoretical derivation, enables the replication of a single breakthrough pressure test result, thereby providing a method for rapidly determining the breakthrough pressure of a large number of caprocks.

[0024] Figure 1 This is a flowchart illustrating the caprock breakthrough pressure prediction method in an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes:

[0025] Step 101: Obtain the breakthrough pressure of the core sample from the caprock region to be tested;

[0026] Step 102: Using the breakthrough pressure of the core sample and the preset conversion formula, obtain the breakthrough pressure at any measuring point in the caprock area to be tested; the preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample; wherein, the permeability and porosity of any measuring point in the caprock area to be tested, and the permeability and porosity of the core sample are known values.

[0027] from Figure 1 As shown in the flowchart, in this embodiment of the invention, the breakthrough pressure of the core sample from the caprock region to be tested is obtained; using the breakthrough pressure of the core sample and a preset conversion formula, the breakthrough pressure at any measuring point in the caprock region to be tested is obtained; the preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample; wherein, the permeability and porosity of any measuring point in the caprock region to be tested, and the permeability and porosity of the core sample are known values. In determining the breakthrough pressure of the caprock, this embodiment of the invention, compared with existing technical solutions, only requires one acquisition and testing of the caprock core sample, and only needs to input the basic parameters of porosity and permeability at any point in the caprock to determine the breakthrough pressure at that point. This allows for the rapid acquisition of massive breakthrough pressure data of the study area in a short time, offering advantages such as speed, low workload, and theoretical support. It is suitable for rapid operational condition evaluation of the breakthrough pressure of caprock in geological bodies such as gas reservoirs, gas storage facilities, and oil reservoirs, filling the industry gap in rapidly obtaining the breakthrough pressure field of caprock.

[0028] The method for predicting caprock breakthrough pressure in the embodiments of the present invention will be explained in detail below.

[0029] First, obtain core samples from the area of ​​the caprock to be tested. During the process, select a suitable location within the caprock area to obtain the core sample. Only one core sample acquisition is required, and only one sample needs to be obtained. During the extraction of the core sample using a core drill bit, minimize disturbance to the core sample and maintain its original state.

[0030] The core samples were then tested and analyzed in the laboratory using standard methods, corresponding to the permeability k. o Porosity φ o The breakthrough pressure p of the core sample was obtained by testing. co .

[0031] Subsequently, for any point in the caprock region to be tested, the corresponding breakthrough pressure is calculated using the conversion method proposed in this embodiment of the invention.

[0032] In one embodiment, obtaining the breakthrough pressure at any measuring point in the cover layer region to be measured using the breakthrough pressure of the core sample and a preset conversion formula may include:

[0033] For any measuring point in the caprock region to be measured, the permeability k at that measuring point is used. i Porosity φ i The breakthrough pressure p of the core sample co The breakthrough pressure at the measuring point is obtained by using a preset conversion formula; the permeability and porosity of the measuring point are calculated in advance based on the difference in well logging data.

[0034] In the geological model, the permeability and porosity at any point are known values, derived from the difference calculation of well logging data. The calculation process is routine and can be directly read from the geological model. The geological model can be pre-constructed using seismic and well logging data from the caprock area to be measured.

[0035] That is, the porosity, permeability and other parameters of the formation used in the embodiments of the present invention are all known and conventional data. The only thing that needs to be tested is the breakthrough pressure of the core sample.

[0036] In one embodiment, the preset conversion formula is expressed as follows:

[0037]

[0038] In the formula, p ci For the breakthrough pressure of the measuring point, k i φ i Permeability and porosity at the measuring points, respectively, k o φ o p co These represent the permeability, porosity, and breakthrough pressure of the core sample, respectively.

[0039] During implementation, select any point in the caprock region to be tested, and the permeability k at that point is... i Porosity φ i It is known that, according to the conversion formula proposed in this invention, the breakthrough pressure p corresponding to this point can be calculated. ci .

[0040] The preset conversion formula has few parameters, is relatively simple, easy to use, and fast to calculate. Moreover, it does not require any regression processing. According to the preset conversion formula proposed in the embodiment of the present invention, the breakthrough pressure at any point in the cover layer region to be tested can be predicted quickly and in large quantities using only the test results of a single breakthrough pressure test, which greatly improves the efficiency and accuracy of breakthrough pressure prediction.

[0041] In one embodiment, the preset conversion formula can be obtained through mathematical fitting and / or machine learning.

[0042] Figure 2 This is a diagram illustrating a specific embodiment of the caprock breakthrough pressure prediction method of the present invention, as shown in the figure. Figure 2 As shown, after obtaining the breakthrough pressure at any measuring point in the cover layer region to be tested in step 102, it may further include:

[0043] Step 201: Based on the breakthrough pressure at each measuring point, draw a breakthrough pressure field distribution map of the cover layer area to be measured.

[0044] In practice, step 102 is programmed to plot the breakthrough pressure at any point, resulting in a breakthrough pressure field distribution map of the caprock region to be tested. The breakthrough pressure field distribution map can distinguish different pressure conditions by color and display pressure values ​​simultaneously. The breakthrough pressure field distribution map can be displayed in two-dimensional or three-dimensional form. In this example, the breakthrough pressure conditions of the caprock region to be tested can be intuitively displayed, allowing users to easily understand the breakthrough pressure situation of the caprock region and improving the user experience.

[0045] Figure 3 This is a diagram illustrating a specific embodiment of the caprock breakthrough pressure prediction method of the present invention, as shown in the figure. Figure 3 As shown, the method includes:

[0046] Step 301: Test the breakthrough pressure of the core sample (corresponding to permeability and porosity);

[0047] Step 302: For the permeability and porosity of any point in the caprock region, the breakthrough pressure of any point in the caprock region is calculated using the preset conversion formula proposed in this embodiment of the invention.

[0048] Step 303: Process step 302 in a programmed manner and draw a distribution map of the breakthrough pressure field in the caprock region.

[0049] When drawing the distribution map of the pressure field in the caprock area, all pressure data are first collected and preprocessed. Preprocessing includes, but is not limited to, outlier removal and interpolation. Based on the geological model, appropriate visualization software is selected to map the pressure values. Finally, different colors are used to represent different pressure levels, and isobars can also be drawn to show the continuous changes in pressure.

[0050] As can be seen, the breakthrough pressure conversion method in this embodiment of the invention only requires testing the breakthrough pressure of one core sample as a seed. Using the conversion method of this embodiment, the breakthrough pressure of any core sample or core sample at any geological location can be quickly determined. The porosity, permeability, and other parameters of the formation used are all known and conventional data.

[0051] The embodiments of this invention are applicable to the quantitative evaluation of the sealing performance of the direct caprock area of ​​gas reservoirs converted into gas storage facilities, oil reservoirs converted into gas storage facilities, and water-bearing reservoirs converted into gas storage facilities. It can quickly obtain massive breakthrough pressure in the study area in a short time, forming a breakthrough pressure field covering the entire area, and providing detailed and scientific sealing support for decision-making experts.

[0052] The following is a comparative example analysis.

[0053] To discuss the feasibility of converting a gas field into a gas storage facility, the sealing performance of the caprock was evaluated. Core samples of light red fine sandstone from the Upper Triassic Yanchang Formation were obtained through drilling. The breakthrough pressure of 8.458 MPa was obtained from the experiment and used as a baseline. In order to predict the breakthrough pressure of the surrounding brownish-red mudstone caprock, a prediction of 12.15 MPa was obtained. This value is close to the experimental value of 12.07 MPa, with a difference of only 6.6%, which is within the acceptable range for sealing performance evaluation.

[0054] This invention also provides a caprock breakthrough pressure prediction device, as described in the following embodiments. Since the principle behind this device is similar to that of the caprock breakthrough pressure prediction method, the implementation of this device can be found in the implementation of the method, and repeated details will not be elaborated further.

[0055] Figure 4 This is a schematic diagram of the caprock breakthrough pressure prediction device in an embodiment of the present invention, as shown below. Figure 4 As shown, the device includes:

[0056] Sample testing module 401 is used to obtain the breakthrough pressure of core samples from the caprock region to be tested.

[0057] The breakthrough pressure calculation module 402 is used to obtain the breakthrough pressure at any measuring point in the caprock region to be tested using the breakthrough pressure of the core sample and a preset conversion formula. The preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample. The permeability and porosity of any measuring point in the caprock region to be tested, as well as the permeability and porosity of the core sample, are known values.

[0058] In one embodiment, the breakthrough pressure calculation module 402 is specifically used for:

[0059] For any measuring point in the caprock area to be tested, the breakthrough pressure of the measuring point is obtained by using the permeability, porosity, breakthrough pressure of the core sample, and a preset conversion formula; wherein, the permeability and porosity of the measuring point are calculated in advance based on the difference in well logging data.

[0060] In one embodiment, the preset conversion formula is expressed as follows:

[0061]

[0062] In the formula, p ci For the breakthrough pressure of the measuring point, k i φ i Permeability and porosity at the measuring points, respectively, k o φo p co These represent the permeability, porosity, and breakthrough pressure of the core sample, respectively.

[0063] In one embodiment, it also includes:

[0064] The pressure field distribution map generation module is used to draw the pressure field distribution map of the cover layer region to be tested based on the breakthrough pressure of any measuring point obtained by the breakthrough pressure calculation module 402 after breakthrough pressure at each measuring point.

[0065] Figure 5 This is a schematic diagram of a computer device in an embodiment of the present invention, such as... Figure 5 As shown, this embodiment of the invention also provides a computer device 500, including a processor 501, a memory 502, and a computer program 503 stored in the memory 502 and executable on the processor 501. When the processor 501 executes the computer program 503, it implements the above-mentioned caprock breakthrough pressure prediction method.

[0066] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for predicting caprock breakthrough pressure.

[0067] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described method for predicting caprock breakthrough pressure.

[0068] In this embodiment of the invention, the breakthrough pressure of a core sample from the caprock region to be tested is obtained. Using the breakthrough pressure of the core sample and a preset conversion formula, the breakthrough pressure at any measuring point in the caprock region to be tested is obtained. The preset conversion formula reflects the relationship between the breakthrough pressure, permeability, and porosity of any measuring point and the breakthrough pressure, permeability, and porosity of the core sample. The permeability and porosity of any measuring point in the caprock region to be tested, and the permeability and porosity of the core sample, are known values. Compared with existing technologies, this embodiment of the invention, when determining the breakthrough pressure of the caprock, only requires one acquisition and testing of the caprock core sample. It only needs to input the basic parameters of porosity and permeability at any point in the caprock to determine the breakthrough pressure at that point. This allows for the rapid acquisition of massive breakthrough pressure data of the study area in a short time, offering advantages such as speed, low workload, and theoretical support. It is suitable for rapid operational condition evaluation of the breakthrough pressure of caprocks in geological bodies such as gas reservoirs, gas storage facilities, and oil reservoirs, filling a gap in the industry for rapidly obtaining caprock breakthrough pressure fields.

[0069] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0071] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0072] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0073] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cap- rock breakthrough pressure prediction method characterized by, The method comprises the following steps: obtaining the breakthrough pressure of a core sample of the to-be-tested caprock region; obtaining the breakthrough pressure of any measuring point of the to-be-tested caprock region by using the breakthrough pressure of the core sample and a preset conversion formula; the preset conversion formula reflects the relationship between the breakthrough pressure, the permeability and the porosity of any measuring point and the breakthrough pressure, the permeability and the porosity of the core sample; wherein the permeability and the porosity of any measuring point of the to-be-tested caprock region and the permeability and the porosity of the core sample are known values.

2. The cap- penetration pressure prediction method of claim 1, wherein, The method for obtaining the breakthrough pressure of any measuring point of the to-be-tested caprock region by using the breakthrough pressure of the core sample and the preset conversion formula comprises the following steps: for any measuring point of the to-be-tested caprock region, the breakthrough pressure of the measuring point is obtained by using the permeability and the porosity of the measuring point, the breakthrough pressure of the core sample and the preset conversion formula; wherein the permeability and the porosity of the measuring point are obtained in advance according to the difference of logging data.

3. The cap- penetration pressure prediction method of claim 2, wherein, The preset conversion formula is as follows: where p ci is the breakthrough pressure at the measurement point, k i , φ i are the permeability and porosity at the measurement point, k o , φ o , p co are the permeability, porosity and breakthrough pressure of the core sample, respectively.

4. The cap- penetration pressure prediction method of claim 1, wherein, After the breakthrough pressure of any measuring point of the to-be-tested caprock region is obtained, the method further comprises the following steps: a breakthrough pressure field distribution map of the to-be-tested caprock region is drawn according to the breakthrough pressure of each measuring point.

5. A cap- breakthrough pressure prediction apparatus characterized by comprising: The method comprises the following steps: a sample testing module is configured to obtain the breakthrough pressure of a core sample of the to-be-tested caprock region; a breakthrough pressure calculation module is configured to obtain the breakthrough pressure of any measuring point of the to-be-tested caprock region by using the breakthrough pressure of the core sample and a preset conversion formula; the preset conversion formula reflects the relationship between the breakthrough pressure, the permeability and the porosity of any measuring point and the breakthrough pressure, the permeability and the porosity of the core sample; wherein the permeability and the porosity of any measuring point of the to-be-tested caprock region and the permeability and the porosity of the core sample are known values.

6. The cap penetration pressure prediction apparatus of claim 5, wherein The breakthrough pressure calculation module is specifically configured to: for any measuring point of the to-be-tested caprock region, the breakthrough pressure of the measuring point is obtained by using the permeability and the porosity of the measuring point, the breakthrough pressure of the core sample and the preset conversion formula; wherein the permeability and the porosity of the measuring point are obtained in advance according to the difference of logging data.

7. The cap penetration pressure prediction apparatus of claim 5, wherein The preset conversion formula is as follows: In the formula, p ci is the breakthrough pressure of the measuring point, k i , φ i are the permeability and porosity of the measuring point, respectively, k o , φ o , p co are the permeability, porosity and breakthrough pressure of the core sample, respectively.

8. The cap penetration pressure prediction apparatus of claim 5, wherein The method further comprises the following steps: a pressure field distribution map generation module is configured to, after the breakthrough pressure calculation module obtains the breakthrough pressure of any measuring point of the to-be-tested caprock region, draw a breakthrough pressure field distribution map of the to-be-tested caprock region according to the breakthrough pressure of each measuring point.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the caprock breakthrough pressure prediction method in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the caprock breakthrough pressure prediction method in any one of claims 1 to 4.

11. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program is executed by the processor to realize the caprock breakthrough pressure prediction method in any one of claims 1 to 4.

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