A method and device for determining spontaneous imbibition performance of a reservoir

Abstract

The present application relates to the field of oil and gas field exploration, and particularly relates to a method and device for determining spontaneous imbibition performance of reservoirs. The method comprises segmenting a core according to a preset interval; determining initial overall oil content of the core and initial segmented oil content of the core before spontaneous imbibition; determining current overall oil content of the core and current segmented oil content of the core at different spontaneous imbibition times; determining spontaneous imbibition oil production and spontaneous imbibition efficiency of each segment of the core at different spontaneous imbibition time periods according to the initial segmented oil content and the current segmented oil content of the core; determining spontaneous imbibition contribution rate of each segment of the core at different spontaneous imbibition time periods according to the initial overall oil content, the current overall oil content and the spontaneous imbibition oil production of each segment of the core; and determining spontaneous imbibition performance of each segment of the core according to the spontaneous imbibition efficiency and the spontaneous imbibition contribution rate. The present application segments the core and calculates spontaneous imbibition performance of each segment of the core, thereby providing a basis for optimizing construction parameters.

Description

Technical Field

[0001] This article relates to the field of oil and gas field exploration, and in particular to a method and apparatus for determining the spontaneous permeation performance of reservoirs. Background Technology

[0002] Shale oil extraction, as an important technology in oil and gas field development, has been widely applied in oil and gas fields worldwide. Shale oil refers to liquid hydrocarbons existing in organic-rich shale formations in various forms, including free, adsorbed, and dissolved states, and is a typical type of self-generated and self-storing in-situ accumulated oil and gas. However, shale oil reservoirs are characterized by low porosity, low permeability, and high capillary forces, making it difficult to utilize the oil within the pores. The spontaneous adsorption induced by high capillary forces allows water to spontaneously displace the oil, which is a crucial mechanism in shale oil extraction. Therefore, efficient spontaneous adsorption capacity of shale oil is of great significance for shale reservoir development research.

[0003] However, due to the low porosity and low permeability of shale oil reservoirs, the volume of oil produced by spontaneous seepage is very small. The existing methods for evaluating the spontaneous seepage performance of shale reservoirs have the following problems: (1) Existing technologies use measuring instruments such as measuring cylinders to measure the amount of oil produced by seepage, which has a large error and cannot reflect the real-time seepage process; (2) Existing technologies can only simulate the static seepage process under normal temperature and pressure, and cannot simulate the dynamic seepage process under formation conditions.

[0004] To address the problems of large measurement errors in oil absorption and the inability to simulate dynamic absorption processes in existing technologies, a method for determining the spontaneous absorption performance of reservoirs is needed. Summary of the Invention

[0005] To address the problems of the prior art, this embodiment provides a method, apparatus, computer equipment, and computer storage medium for determining the spontaneous permeation performance of a reservoir.

[0006] This article provides a method for determining the spontaneous adsorption performance of a reservoir, including:

[0007] The core sample is segmented according to a preset interval;

[0008] The initial overall oil content and the initial segmental oil content of the core before spontaneous infiltration were determined respectively.

[0009] Determine the current overall oil content and the current segmental oil content of the core at different spontaneous infiltration times;

[0010] Based on the initial segment oil content and the current segment oil content of the core, determine the spontaneous oil recovery rate and spontaneous oil recovery efficiency of each core segment during different spontaneous adsorption time periods.

[0011] Based on the initial overall oil content of the core, the current overall oil content, and the spontaneous seepage recovery of each core segment, determine the spontaneous seepage contribution rate of each core segment during different spontaneous seepage time periods.

[0012] The spontaneous absorption performance of each core segment was determined based on the spontaneous absorption efficiency and spontaneous absorption contribution rate.

[0013] According to one aspect of the embodiments herein, determining the spontaneous adsorption efficiency of each core segment includes:

[0014] The spontaneous absorption rate of each core segment is determined using the following formula: Where η1 is the spontaneous absorption rate of each core segment, x represents a certain location in a core segment, Δx represents the unit length, t represents the spontaneous absorption time, and t0 represents the initial time before spontaneous absorption. f represents the oil signal amplitude at a certain location x in the core at the initial time t0. t (x) represents the signal amplitude at a certain location x in the core under an absorption time t. This represents the sum of T2 spectral signals corresponding to a certain segment of the core at an initial time t0, i.e., the oil content of that core segment, ∑f t (x)×Δx represents the sum of the T2 spectrum signal quantities corresponding to a certain segment of the core at an absorption time t, i.e., the oil content of a certain core segment. This represents the difference in oil content of a certain core segment within the spontaneous infiltration time period t.

[0015] According to one aspect of the embodiments herein, determining the spontaneous permeation contribution rate of each core segment includes:

[0016] The spontaneous permeation contribution rate of the entire core was determined using the following formula: Where η is the spontaneous adsorption contribution rate of the entire core, x represents a certain location on the core, Δx represents the unit length, t represents the spontaneous adsorption time, t0 represents the initial time before spontaneous adsorption, and l is the total length of the core. f represents the oil signal amplitude at a certain location x in the core at the initial time t0. t (x) represents the signal amplitude at a certain location x in the core under an absorption time t. This represents the total T2 spectral signal quantity of the entire core at the initial time t0, i.e., the oil content of the entire core, ∑f t (l)×Δx represents the sum of the T2 spectrum signal quantities corresponding to a certain period of permeation time t, that is, the oil content of the entire core. This represents the difference in oil content at a certain point within the spontaneous percolation time period t.

[0017] According to one aspect of the embodiments herein, determining the spontaneously absorbed oil production of each core segment within different spontaneous absorption time periods, based on the initial segment oil content and the current segment oil content, includes: determining the change in oil content of each core segment within the spontaneous absorption time period based on the initial segment oil content and the current segment oil content, wherein the change in oil content is the spontaneously absorbed oil production of each core segment.

[0018] According to one aspect of the embodiments herein, determining the spontaneous absorption performance of each core segment based on spontaneous absorption efficiency and spontaneous absorption contribution rate includes: when the spontaneous absorption efficiency is greater than a first preset threshold and the spontaneous absorption contribution rate is greater than a second preset threshold, the spontaneous absorption performance of that core segment is determined to be excellent.

[0019] According to one aspect of the embodiments herein, determining the initial overall oil content of the core before spontaneous infiltration and the initial segmented oil content of the core includes: determining the initial overall oil content of the core based on the sum of nuclear magnetic resonance T2 spectrum signal energies corresponding to the overall length of the core before spontaneous infiltration; and determining the initial segmented oil content of the core based on the sum of nuclear magnetic resonance T2 spectrum signal energies corresponding to the lengths of the segmented core before spontaneous infiltration.

[0020] According to one aspect of the embodiments herein, determining the current overall oil content and the current segmental oil content of a core at different spontaneous adsorption times includes: determining the spontaneous adsorption time; determining the current overall oil content of the core based on the total energy of the nuclear magnetic resonance T2 spectrum signal corresponding to the overall length of the core at the spontaneous adsorption time; selecting a core segment after a certain segment, and determining the current segmental oil content of the core based on the total energy of the nuclear magnetic resonance T2 spectrum signal corresponding to the length of the core segment after the spontaneous adsorption time.

[0021] This embodiment also provides a device for determining the spontaneous oil absorption performance of a reservoir. The device includes: a core segmentation unit for segmenting the core according to a preset interval; an initial oil content determination unit for determining the initial overall oil content of the core before spontaneous absorption and the initial segmented oil content of the core; a current oil content determination unit for determining the current overall oil content of the core and the current segmented oil content of the core at different spontaneous absorption times; and a spontaneous absorption efficiency determination unit for determining the efficiency of the spontaneous absorption based on the initial segmented oil content of the core. The system includes a first unit for determining the spontaneous oil recovery and spontaneous absorption efficiency of each core segment within different spontaneous absorption time periods, based on the initial overall oil content, the current overall oil content, and the spontaneous oil recovery of each core segment; and a second unit for determining the spontaneous absorption performance of each core segment based on the spontaneous absorption efficiency and the spontaneous absorption contribution rate.

[0022] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for determining the spontaneous permeation performance of a reservoir.

[0023] This embodiment 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 method for determining the spontaneous permeation performance of the reservoir.

[0024] This scheme simulates the dynamic permeation process of shale oil under formation conditions, and divides the core into segments to determine the permeation performance of each segment. The calculation results are accurate, providing a basis for the selection of shale oil reservoir fluids and the optimization of construction parameters, and is suitable for large-scale promotion and application. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments or prior art described herein, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this article. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The diagram shown is a schematic diagram of a reservoir spontaneous percolation simulation device according to an embodiment of this paper;

[0027] Figure 2 This is a flowchart illustrating a method for determining the spontaneous permeation performance of a reservoir, as described in this embodiment.

[0028] Figure 3 The diagram shown is a flowchart of a method for determining the initial overall oil content and the initial segmented oil content according to an embodiment of this paper.

[0029] Figure 4 The diagram shown is a flowchart of a method for determining the current overall oil content and the current segment oil content according to an embodiment of this article.

[0030] Figure 5 The image shown is a schematic diagram of a segmented T2 spectrum of a core sample according to one embodiment of this paper.

[0031] Figure 6 The image shown is a schematic diagram of a nuclear magnetic resonance T2 spectrum according to an embodiment of this paper;

[0032] Figure 7 The diagram shown is a schematic representation of a reservoir spontaneous permeation performance determination device according to an embodiment of this paper.

[0033] Figure 8The diagram shown is a structural schematic of a computer device according to an embodiment of this article.

[0034] Explanation of symbols in the attached drawings:

[0035] 101. Nuclear magnetic resonance (NMR) equipment;

[0036] 102. Core holder;

[0037] 1021. Core sleeve;

[0038] 1022. Heating jacket;

[0039] 1023. Temperature sensor;

[0040] 1024. Confining pressure loading space;

[0041] 1025. Pressure sensor;

[0042] 1026. Liquid storage space;

[0043] 103. Injection pipeline;

[0044] 104. Intermediate container;

[0045] 105. Constant speed and constant pressure pump;

[0046] 106. Core sample;

[0047] 701. Core segmentation unit;

[0048] 702. Initial oil content determination unit;

[0049] 703. Current oil content determination unit;

[0050] 704. Unit for determining spontaneous absorption efficiency;

[0051] 705. Unit for determining the contribution rate of spontaneous infiltration;

[0052] 706. Unit for determining spontaneous permeation performance;

[0053] 802. Computer equipment;

[0054] 804, Processor;

[0055] 806. Memory;

[0056] 808. Drive mechanism;

[0057] 810. Input / Output Module;

[0058] 812. Input devices;

[0059] 814. Output devices;

[0060] 816. Presentation equipment;

[0061] 818. Graphical User Interface;

[0062] 820. Network interface;

[0063] 822. Communication link;

[0064] 824. Communication bus. Detailed Implementation

[0065] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments herein will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments herein, and not all of the embodiments. Based on the embodiments herein, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this document.

[0066] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings herein are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0067] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel.

[0068] It should be noted that the method for determining the spontaneous permeability of reservoirs presented in this paper can be used in the field of oil and gas exploration, as well as in other fields. This paper does not limit the application fields of the method and device for determining the spontaneous permeability of reservoirs.

[0069] During hydraulic fracturing, fractures are formed in the rock formation under the action of fracturing fluid. The fracturing fluid comes into contact with the rock matrix, causing changes in the physical properties of the rock. The interaction between the rock and the fluid allows the fluid to penetrate the rock matrix, a phenomenon known as percolation. Percolation typically reduces the flowback rate of fracturing fluid and can also alter the permeability of the rock reservoir, significantly impacting the production capacity of gas wells.

[0070] Generally, factors affecting permeation include, but are not limited to: reservoir rock pore structure, rock mineral composition, rock bedding, and fluid properties.

[0071] like Figure 1 The diagram shown is a schematic representation of a reservoir spontaneous adsorption simulation device according to an embodiment of this paper. This simulation device is as follows... Figure 1 As shown, the system includes an NMR device 101, a core holder 102, an injection pipeline 103, an intermediate container 104, and a constant-speed, constant-pressure pump 105. The NMR device 101 is used to acquire oil signal quantities in the core 106 of the rock in the core holder 102 in real time. The core holder 102 is used to hold the core 106. After the core 106 is saturated according to its initial oil and water content, it is placed in a core sleeve 1021. A heating sleeve 1022 is provided on the outside of the core holder 102. A temperature sensor 1023 is installed between the heating sleeve 1022 and the shell of the core holder 102, and the temperature sensor 1023 is used to measure the temperature of the core 106 in real time. A confining pressure loading space 1024 is provided inside the core holder 102. A pressure sensor 1025 is installed in the confining pressure loading space 1024, and the pressure sensor 1025 is used to measure the confining pressure on the core 106 in real time. The core holder 102 has an internal injection liquid storage space 1026 to ensure full contact between the injected liquid and the core end face, and uniform self-priming. The injection line 103 is used to inject the displacement liquid into the core end face. The intermediate container 104 is used to hold the prepared displacement liquid, which is heavy water or a heavy water solution prepared according to the on-site fracturing formula. The constant speed and pressure pump 105 is used to displace the liquid in the intermediate container 104 and provide a constant displacement speed or displacement pressure.

[0072] A cylindrical core sample was selected from the well to establish initial oil content and water saturation. The core sample was then placed in the core holder 102. Heavy water or a heavy water solution prepared according to the on-site fracturing formula was selected as the test liquid. The test liquid was placed in an intermediate container 104 and pumped into the core holder 102 using a constant speed and pressure pump 105. The core sample was heated by a heating jacket 1022 and pressurized by a confining pressure pump to simulate the formation conditions and conduct a reservoir spontaneous permeation simulation test.

[0073] Figure 2 The diagram shows a flowchart of a method for determining the spontaneous adsorption performance of a reservoir, as described in this embodiment. This method is applied to... Figure 1 The reservoir spontaneous adsorption simulation device includes the following steps:

[0074] Step 201: Segment the core according to a preset interval. In this step, the core in the reservoir spontaneous permeation simulation device has a certain length. For example, the core length is 60 mm. The core is evenly divided into multiple core segments of the same length according to a preset interval. For example, with a preset interval of 5 mm, the complete core is divided into 12 core segments, each core segment being 5 mm in length.

[0075] Step 202: Determine the initial overall oil content and the initial segmented oil content of the core before spontaneous adsorption. In this step, the initial overall oil content of the core before spontaneous adsorption is: the initial oil content of the entire core before spontaneous adsorption. The initial segmented oil content of the core is: the initial oil content of the segmented core before spontaneous adsorption. For example, in the reservoir spontaneous adsorption simulation device, the core length is 60mm, and the oil content of this core is 500ml. Then the initial overall oil content of the core before spontaneous adsorption is 500ml. As another example, if the segmented core is 5mm long, and this core segment is distributed in the 0-5mm position of the 60mm core, and the oil content of this core segment is 80ml, then the initial segmented oil content of the core is 80ml.

[0076] In this step, the initial overall oil content and initial segmental oil content of the core before spontaneous adsorption can be obtained through NMR analysis. Specifically, the initial overall oil content of the core before spontaneous adsorption can be obtained by performing NMR analysis on the core. Specifically, the initial overall oil content of the core before spontaneous adsorption, i.e., the initial oil content of the entire core, is calculated from the corresponding NMR T2 spectrum of the core before spontaneous adsorption. The specific methods for calculating the initial overall oil content and initial segmental oil content of the core before spontaneous adsorption can be found in [link to relevant documentation]. Figure 4 And its corresponding description.

[0077] Step 203: Determine the current overall oil content and the current segmented oil content of the core at different spontaneous adsorption times. In this step, when spontaneous adsorption occurs in the core, the oil content of both the overall core and the segmented core segments will change. Specifically, in the reservoir spontaneous adsorption simulation device, during the spontaneous adsorption process, the displacing fluid / heavy water is gradually adsorbed into the core. The displacing fluid replaces the crude oil in the core, and the oil in the core is displaced by the displacing fluid. The oil content of the core and core segments will gradually decrease, and the oil signal measured by the NMR equipment will also decrease accordingly. Furthermore, the oil content of the core and core segments at different locations will vary at different spontaneous adsorption times. In this step, the current overall oil content of the core at different spontaneous adsorption times is: the oil content of the complete core at different spontaneous adsorption times during the spontaneous adsorption process; the current segmented oil content of the core is: the oil content of the segmented core at different spontaneous adsorption times during the spontaneous adsorption process.

[0078] Step 204: Based on the initial segment oil content and the current segment oil content of the core, determine the spontaneous adsorption oil recovery and spontaneous adsorption efficiency of each core segment within different spontaneous adsorption time periods. In this step, the spontaneous adsorption oil recovery of each core segment is: the amount of oil recovered from the segmented core segment within the spontaneous adsorption time period; the spontaneous adsorption efficiency of each core segment is: the ratio of the amount of oil recovered from the segmented core segment to the initial oil content of that core segment within the spontaneous adsorption time period. The spontaneous adsorption efficiency of the core may differ at different locations or within different core segments.

[0079] Step 205: Based on the initial overall oil content of the core, the current overall oil content, and the spontaneous seepage recovery of each core segment, determine the spontaneous seepage contribution rate of each core segment within different spontaneous seepage time periods. In this step, the spontaneous seepage contribution rate of each core segment is: the ratio of the spontaneous seepage recovery of the segmented core segment to the spontaneous seepage recovery of the entire core within the spontaneous seepage time period. In this step, the larger this ratio, the larger the spontaneous seepage contribution rate of the core segment; the smaller the ratio, the smaller the spontaneous seepage contribution rate of the core segment.

[0080] Step 206: Determine the spontaneous adsorption performance of each core segment based on the spontaneous adsorption efficiency and spontaneous adsorption contribution rate. In this step, the spontaneous adsorption performance of the core segment can be determined by combining the spontaneous adsorption efficiency and spontaneous adsorption contribution rate. For example, shale has a multi-scale pore structure. By analyzing the spontaneous adsorption performance of the core segment, the porosity characteristics and pore distribution of different core segments can be further determined, which further helps in the selection of shale reservoir fluids and the optimization of construction parameters, and has guiding significance for actual engineering operations.

[0081] In some embodiments of this specification, when the spontaneous adsorption efficiency is greater than a first preset threshold and the spontaneous adsorption contribution rate is greater than a second preset threshold, the spontaneous adsorption performance of the core segment is determined to be excellent. For example, if the first preset threshold is 50% and the second preset threshold is 60%, then if the spontaneous adsorption efficiency and spontaneous adsorption contribution rate of a certain core segment are greater than 50% and 60%, respectively, the spontaneous adsorption of the core segment can be determined to be excellent, which can guide the study of the core segment at that location during actual oil and gas field exploration. In some embodiments of this specification, the values ​​of the first preset threshold and the second preset threshold can be the same. This application can also determine the spontaneous adsorption performance of the core or core segment using other methods based on the spontaneous adsorption efficiency and spontaneous adsorption contribution rate of the core or core segment. This application does not limit the method for determining and evaluating the spontaneous adsorption performance of the core or core segment.

[0082] In some embodiments of this specification, determining the spontaneous adsorption efficiency of each core segment includes: determining the spontaneous adsorption rate of each core segment using the following formula:

[0083] Where η1 is the spontaneous absorption rate of each core segment, x represents a certain location in a core segment, Δx represents a very small unit of length, t represents the spontaneous absorption time, and t0 represents the initial time before spontaneous absorption. f represents the oil signal amplitude at a certain location x in the core at the initial time t0. t (x) represents the signal amplitude at a certain location x in the core under an absorption time t. This represents the sum of T2 spectral signals corresponding to a certain segment of the core at an initial time t0, i.e., the oil content of that core segment, ∑f t (x)×Δx represents the sum of the T2 spectrum signal quantities corresponding to a certain segment of the core at an absorption time t, i.e., the oil content of a certain core segment. This represents the difference in oil content of a certain core segment within the spontaneous infiltration time period t.

[0084] in, This represents the oil signal amplitude at a certain location x in the core at the initial time t0. t (x) represents the signal amplitude at a specific location x in the core at a permeation time t. Here, a specific location in the core can also represent a segment of the core's length. For example, if the overall core length is 60 mm and x is 20, it can represent a segment within the 0-20 mm length range or a segment within the 20-40 mm length range. The value of x representing a specific segment of the core can be determined based on the upper and lower limits of the integral of the spontaneous permeation rate calculation formula η1.

[0085] In some embodiments of this specification, the difference in oil content between the initial time and the percolation time of a core segment is the amount of oil percolated by that core segment within the percolation time t. In some embodiments of this specification, determining the spontaneous percolation oil recovery of each core segment within different spontaneous percolation time periods, based on the initial segment oil content and the current segment oil content, includes: determining the change in oil content of each core segment within the spontaneous percolation time period based on the difference between the initial segment oil content and the current segment oil content; this change in oil content is the spontaneous percolation oil recovery of each core segment. For example, if the initial segment oil content of the 0-20mm segment of the core is 100ml, and the current segment oil content of the core is 90ml after a spontaneous percolation time of 2 hours, then the spontaneous percolation oil recovery of that core segment within 2 hours is the difference between the initial segment oil content and the current segment oil content, which is 10ml.

[0086] The spontaneous adsorption rate of a core segment can be determined by comparing the amount of oil adsorbed within an adsorption time t with the oil content at the initial moment of that core location. The adsorption rate varies at different adsorption times and at different core locations. A higher spontaneous adsorption rate indicates stronger oil adsorption capacity in that core segment; conversely, a lower rate indicates weaker adsorption capacity.

[0087] Specifically, the oil signal amplitude at a certain location x in the core at the initial time t0 and the signal amplitude at a certain location x in the core at the infiltration time t can be obtained from the oil signal variation curves at different infiltration times and different core locations. For example... Figure 5 The diagram shown illustrates a segmented T2 spectrum of a core sample according to an embodiment of this paper. This segmented T2 spectrum can detect the T2 spectral signal intensity at different segments of the core. Specifically, core samples at different locations at different times exhibit different oil volume signal amplitudes. Changes in signal intensity can be acquired by nuclear magnetic resonance (NMR) equipment and displayed as a continuous curve. Furthermore, signal intensity can reflect the oil volume, and there is a positive correlation between signal intensity and oil volume. Figure 5 The horizontal axis represents the core length, and the vertical axis represents the oil content signal amplitude measured by NMR at different locations and times within the core. The figure includes the oil-bearing signal amplitude curves of the entire 60mm core and at various locations at four different time points: 0 hours, 2 hours, 8 hours, and 142 hours. 0 hours represents the initial time before seepage or moment zero; 2 hours, 8 hours, and 142 hours represent 2 hours, 8 hours, and 142 hours of seepage, respectively.

[0088] As shown in the figure, the oil signal amplitude curve within 0-2 hours of core seepage differs significantly from the initial oil signal amplitude, indicating a rapid seepage rate. When the seepage front reaches 23.5 mm from the liquid surface, the oil content in the lower part of the core changes noticeably. Specifically, after 2 hours of seepage, the oil signal amplitude varies at different locations within the core. For example, within a 1-20 mm length segment of the core, the current oil signal amplitude after 2 hours of seepage differs considerably from the initial oil signal amplitude. Specifically, at a core location approximately 20 mm in diameter, after 2 hours of seepage, the current oil volume corresponds to an oil signal amplitude of approximately 6000 a.u., compared to approximately 7200 a.u. at the initial time. This indicates a significant difference in signal amplitude between the initial and current values ​​at this core location after 2 hours of seepage. At a core location 30 mm in diameter, after 2 hours of seepage, the current oil volume corresponds to an oil signal amplitude of approximately 6300 a.u., almost identical to the initial value at this core location. Furthermore, within a core length range of approximately 23 mm to 35 mm after 2 hours of seepage, the oil signal amplitude is almost equal to the initial value within the same core length range. Therefore, it can be concluded that after 2 hours of seepage, a certain amount of oil was seeped from the core within a length range of 1 to 23.5 mm. With a seepage time of 2 hours, almost no oil seeped from the core within a length range of 23.5 mm to 35.5 mm, almost identical to the oil content at the initial time. After 8 hours and 142 hours of seepage, the oil signal curves showed similar changes with core length, with minimal differences. This indicates that the seepage rate almost decreased to zero during the 8-142 hour seepage process. At the seepage front reaching 55 mm from the liquid surface, the oil content in the core changed little. The main changes in oil content occurred between 25 and 50 mm.

[0089] Depend on Figure 2 It can be seen that the spontaneous absorption rate of a core segment can be determined by the ratio of the amount of oil absorbed within the absorption time t to the oil content at the initial moment of that core location. Figure 5 Taking infiltration times of 2 hours and 8 hours as examples, the infiltration rate of the 1-20mm core segment was 70.24% within 2 hours, significantly higher than the 27.64% infiltration rate of the same core segment within 2-8 hours. The infiltration rate of the 1-20mm core segment within 2 hours was also higher than that of the 23-35mm core segment within 8 hours.

[0090] In some embodiments of this specification, determining the spontaneous adsorption contribution rate of each core segment includes using the following formula:

[0091] Where η is the spontaneous adsorption contribution rate of the entire core, x represents a certain location on the core, Δx represents a very small unit of length, t represents the spontaneous adsorption time, t0 represents the initial time before spontaneous adsorption, and l is the total length of the core. f represents the oil signal amplitude at a certain location x in the core at the initial time t0. t (x) represents the signal amplitude at a certain location x in the core under an absorption time t. This represents the total T2 spectral signal quantity corresponding to the entire core at the infiltration time t0, i.e., the oil content of the entire core, ∑f t (l)×Δx represents the total T2 spectrum signal quantity corresponding to the entire core at the infiltration time t, that is, the oil content of the entire core. This represents the difference in oil content throughout the entire core sample during the spontaneous infiltration time period t.

[0092] The spontaneous adsorption rate of each core segment is the ratio of the oil recovery rate of that segment to the total oil recovery rate of the entire core at adsorption time t. For example, if l is 60 mm, it represents the length of the entire core. If, at the initial time, the oil content of the entire core... If the current oil content of the whole core is 100ml at an absorption time t, then the absorption oil recovery of the whole core at an absorption time t is determined to be 400ml. The initial spontaneous absorption oil recovery of the 0-20ml core segment at the absorption time is 100ml. Therefore, according to the above formula, the spontaneous absorption contribution rate of this core segment can be calculated as 100 / 400ml = 25%.

[0093] Figure 3 The diagram shown is a flowchart of a method for determining the initial overall oil content and the initial segmented oil content according to an embodiment of this paper. It includes the following steps:

[0094] Step 301: Determine the initial overall oil content of the core based on the NMR T2 spectrum signal corresponding to the overall length of the core before spontaneous adsorption. In some embodiments of this specification, NMR equipment is used to perform NMR testing on the entire core before adsorption until the characteristics of the measured NMR signal spectrum no longer change. Using the NMR signal obtained from the NMR measurement and porosity standard samples, a linear correspondence between the peak area and oil volume in the NMR T2 spectrum of the shale oil reservoir core before adsorption is established. The oil-bearing volume of the core is further determined based on the NMR signal intensity. In some embodiments of this specification, the correspondence between the NMR T2 spectrum area and oil volume is established using the following formula:

[0095] V 油 =α×S 峰

[0096] Among them, V油 S represents the oil-bearing volume in the core, α is a coefficient obtained through porosity calibration, and S 峰 This represents the peak area in the T2 NMR spectrum.

[0097] By measuring the changes in signal amplitude of the core sample at different absorption times using nuclear magnetic resonance (NMR), the distribution of saturated oil in the core sample can be obtained. Furthermore, the pore size and distribution within the core sample can be determined.

[0098] Step 302: Determine the initial oil content of the core segments based on the sum of the T2 spectral signal energies corresponding to the lengths of the segmented cores before spontaneous adsorption. In this step, the core is cut into uniformly long segments, and NMR tests are performed on the segmented cores before adsorption using NMR equipment until the characteristics of the measured NMR signal spectrum no longer change. The initial oil content is determined based on the T2 spectral signal energy corresponding to the segmented core segments and the above formula. This represents the sum of T2 spectrum signals corresponding to a certain segment of the core at the initial time t0, which determines the initial oil content of the core segment.

[0099] Figure 4 The diagram shown is a flowchart of a method for determining the current overall oil content and the current segment oil content according to an embodiment of this paper. The method specifically includes the following steps:

[0100] Step 401: Determine the spontaneous adsorption time. This step determines a spontaneous adsorption time in reservoir spontaneous adsorption simulation tests corresponding to different spontaneous adsorption times. For example, the spontaneous adsorption time is 2 hours.

[0101] Step 402: Based on the sum of the nuclear magnetic resonance T2 spectrum signal energies corresponding to the total length of the core under the spontaneous infiltration time, determine the current overall oil content of the core. The method for determining the current overall oil content of the core in this step is similar to... Figure 3 The method in step 301 is the same. This step will not be described in detail here.

[0102] Step 403: Select a core segment after a certain segmentation. Based on the total energy of the nuclear magnetic resonance T2 spectrum signal corresponding to the length of the core segment after the spontaneous adsorption time, determine the oil content of the current segment of the core. Divide the core into segments and use the aforementioned step 302 to determine the oil content of the core segment under the condition of a spontaneous adsorption time of 2 hours.

[0103] Figure 5 The figure shows a segmented T2 spectrum of a core sample as described in this embodiment. This T2 spectrum displays oil signal quantity curves at different core locations under different permeation times. The figure includes the changes in oil signal quantity at various core locations at the initial time / time zero before permeation, 2 hours after permeation, 8 hours after permeation, and 142 hours after permeation.

[0104] Figure 6 The image shows a schematic diagram of a nuclear magnetic resonance T2 spectrum according to an embodiment of this paper. The horizontal axis of the T2 spectrum represents the relaxation time, and the vertical axis represents the amplitude of the oil quantity signal. Utilizing... Figure 6 The T2 spectrum shown can be used to calculate the degree of core extraction at different permeation times.

[0105] like Figure 7 The diagram shown is a structural schematic of a reservoir spontaneous adsorption performance determination device according to an embodiment of this paper. The basic structure of the device is illustrated in the diagram. The functional units and modules can be implemented using software, general-purpose chips, or specific chips to determine the reservoir spontaneous adsorption performance. The device specifically includes:

[0106] Core segmentation unit 701 is used to segment the core according to a preset interval;

[0107] The initial oil content determination unit 702 is used to determine the initial overall oil content of the core before spontaneous infiltration and the initial segmental oil content of the core, respectively.

[0108] The current oil content determination unit 703 is used to determine the current overall oil content and the current segmental oil content of the core at different spontaneous percolation times.

[0109] The spontaneous permeation efficiency determination unit 704 is used to determine the spontaneous permeation oil production and spontaneous permeation efficiency of each segment of the core during different spontaneous permeation time periods based on the initial segment oil content and the current segment oil content of the core.

[0110] The spontaneous permeation contribution rate determination unit 705 is used to determine the spontaneous permeation contribution rate of each core segment during different spontaneous permeation time periods based on the initial overall oil content of the core, the current overall oil content, and the spontaneous permeation oil production of each core segment.

[0111] The spontaneous permeation performance determination unit 706 is used to determine the spontaneous permeation performance of each core segment based on the spontaneous permeation efficiency and spontaneous permeation contribution rate.

[0112] This scheme simulates the dynamic permeation process of shale oil under formation conditions, and divides the core into segments to determine the permeation performance of each segment. The calculation results are accurate, providing a basis for the selection of shale oil reservoir fluids and the optimization of construction parameters, and is suitable for large-scale promotion and application.

[0113] like Figure 8As shown, a computer device provided in this embodiment is used, wherein the above-described method for determining the spontaneous adsorption performance of a reservoir operates on computer device 802. Computer device 802 may include one or more processors 804, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. Computer device 802 may also include any memory 806 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, memory 806 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory may provide volatile or non-volatile retention of information. Further, any memory may represent a fixed or removable component of computer device 802. In one case, when processor 804 executes associated instructions stored in any memory or combination of memories, computer device 802 may perform any operation of the associated instructions. The computer device 802 also includes one or more drive mechanisms 808 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0114] Computer device 802 may also include an input / output module 810 (I / O) for receiving various inputs (via input device 812) and providing various outputs (via output device 814). A specific output mechanism may include a presentation device 816 and an associated graphical user interface (GUI) 818. In other embodiments, the input / output module 810 (I / O), input device 812, and output device 814 may be omitted, and the device may function solely as a computer device within a network. Computer device 802 may also include one or more network interfaces 820 for exchanging data with other devices via one or more communication links 822. One or more communication buses 824 couple the components described above together.

[0115] Communication link 822 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 822 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0116] Corresponding to Figures 2 to 4 In addition to the methods described above, this embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described methods.

[0117] This embodiment also provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to perform the following: Figures 2 to 5 The method shown.

[0118] It should be understood that in the various embodiments of this document, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0119] It should also be understood that, in the embodiments herein, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0120] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0121] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0122] In the embodiments provided herein, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0123] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described herein, depending on actual needs.

[0124] Furthermore, the functional units in the various embodiments of this document can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0125] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this paper, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this paper. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0126] This document uses specific embodiments to illustrate the principles and implementation methods of this document. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this document. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this document. Therefore, the content of this specification should not be construed as a limitation of this document.

Claims

1. A method for determining the spontaneous permeation performance of a reservoir, characterized in that, The method includes: The core sample is segmented according to a preset interval; The initial overall oil content and the initial segmental oil content of the core before spontaneous infiltration were determined respectively. Determine the current overall oil content and the current segmental oil content of the core at different spontaneous infiltration times; Based on the initial oil content of the core segments and the current oil content of the core segments, the spontaneous oil recovery rate and spontaneous absorption efficiency of each core segment are determined within different spontaneous absorption time periods. Specifically, determining the spontaneous absorption efficiency of each core segment includes using the following formula: = ,in, The spontaneous permeation efficiency of each core segment is given. This indicates a specific location within a certain core sample segment. The unit length is represented by t, and the spontaneous osmosis time is represented by t. Indicates the initial time before spontaneous osmosis. Indicates the initial time A certain location in the rock core The corresponding oil signal amplitude, This indicates the location of a core sample at a given infiltration time t. The corresponding signal amplitude, Indicates the initial time The sum of the T2 spectrum signal corresponding to a certain segment of the lower core indicates the oil content of that core segment. This represents the sum of T2 spectral signals corresponding to a certain segment of the core at an absorption time t, i.e., the oil content of that core segment. This represents the difference in oil content of a certain core segment within the spontaneous infiltration time period t; Based on the initial overall oil content of the core, the current overall oil content, and the spontaneous seepage recovery rate of each core segment, the spontaneous seepage contribution rate of each core segment is determined within different spontaneous seepage time periods. The determination of the spontaneous seepage contribution rate of each core segment includes: The spontaneous permeation contribution rate of the entire core was determined using the following formula: = ,in, The contribution rate of spontaneous permeation to the overall core. This indicates a specific location on the rock core. The unit length is represented by t, and the spontaneous osmosis time is represented by t. Indicates the initial time before spontaneous osmosis. The total length of the core sample. Indicates the initial time A certain location in the rock core The corresponding oil signal amplitude, This indicates the location of a core sample at a given infiltration time t. The corresponding signal amplitude, Indicates the initial time The sum of the T2 spectrum signal corresponding to the entire core, i.e. the oil content of the entire core. This represents the total T2 spectral signal intensity of the entire core at an absorption time t, which is equivalent to the oil content of the entire core. This represents the difference in oil content throughout the entire core during the spontaneous infiltration time period t. The spontaneous absorption performance of each core segment was determined based on the spontaneous absorption efficiency and spontaneous absorption contribution rate.

2. The method for determining the spontaneous permeation performance of a reservoir according to claim 1, characterized in that, Based on the initial segment oil content and the current segment oil content of the core, the spontaneous oil recovery volume of each core segment during different spontaneous adsorption time periods is determined as follows: Based on the initial segment oil content and the current segment oil content of the core, the change in oil content of each segment of the core during the spontaneous seepage period is determined, and the change in oil content is the spontaneous seepage oil production of each segment of the core.

3. The method for determining the spontaneous permeation performance of a reservoir according to claim 2, characterized in that, The spontaneous adsorption performance of each core segment was determined based on the spontaneous adsorption efficiency and the spontaneous adsorption contribution rate, including: When the spontaneous absorption efficiency is greater than a first preset threshold and the spontaneous absorption contribution rate is greater than a second preset threshold, the spontaneous absorption performance of the core segment is determined to be excellent.

4. The method for determining the spontaneous permeation performance of a reservoir according to claim 1, characterized in that, The initial overall oil content and the initial segmental oil content of the core before spontaneous infiltration were determined separately, including: The initial overall oil content of the core was determined based on the sum of the nuclear magnetic resonance T2 spectrum signal energies corresponding to the overall length of the core before spontaneous infiltration. The initial oil content of the core segments is determined based on the sum of the nuclear magnetic resonance T2 spectrum signal energies corresponding to the lengths of the segmented cores before spontaneous infiltration.

5. The method for determining the spontaneous permeation performance of a reservoir according to claim 1, characterized in that, The current overall oil content and the current segmental oil content of the core were determined at different spontaneous infiltration times, including: Determine the spontaneous absorption time; The current overall oil content of the core is determined based on the sum of the nuclear magnetic resonance T2 spectrum signal energy corresponding to the overall length of the core under the spontaneous infiltration time. Select a core segment after a certain segment, and determine the oil content of the current segment of the core based on the sum of the nuclear magnetic resonance T2 spectrum signal energy corresponding to the length of the core segment after the spontaneous absorption time.

6. A device for determining the spontaneous permeation performance of a reservoir, characterized in that, The device includes: A core segmentation unit is used to segment the core according to a preset interval; The initial oil content determination unit is used to determine the initial overall oil content of the core before spontaneous infiltration and the initial segmental oil content of the core, respectively. The current oil content determination unit is used to determine the current overall oil content and the current segment oil content of the core under different spontaneous permeation times. The spontaneous adsorption efficiency determination unit is used to determine the spontaneous adsorption oil production and spontaneous adsorption efficiency of each core segment within different spontaneous adsorption time periods, based on the initial segment oil content and the current segment oil content. Determining the spontaneous adsorption efficiency of each core segment includes using the following formula: = ,in, The spontaneous permeation efficiency of each core segment is given. This indicates a specific location within a certain core sample segment. The unit length is represented by t, and the spontaneous osmosis time is represented by t. Indicates the initial time before spontaneous osmosis. Indicates the initial time A certain location in the rock core The corresponding oil signal amplitude, This indicates the location of a core sample at a given infiltration time t. The corresponding signal amplitude, Indicates the initial time The sum of the T2 spectrum signal corresponding to a certain segment of the lower core indicates the oil content of that core segment. This represents the sum of T2 spectral signals corresponding to a certain segment of the core at an absorption time t, i.e., the oil content of that core segment. This represents the difference in oil content of a certain core segment within the spontaneous infiltration time period t; The spontaneous adsorption contribution rate determination unit is used to determine the spontaneous adsorption contribution rate of each core segment within different spontaneous adsorption time periods, based on the initial overall oil content, the current overall oil content, and the spontaneous adsorption oil production of each core segment. The determination of the spontaneous adsorption contribution rate of each core segment includes: The spontaneous permeation contribution rate of the entire core was determined using the following formula: = ,in, The contribution rate of spontaneous permeation to the overall core. This indicates a specific location on the rock core. The unit length is represented by t, and the spontaneous osmosis time is represented by t. Indicates the initial time before spontaneous osmosis. The total length of the core sample. Indicates the initial time A certain location in the rock core The corresponding oil signal amplitude, This indicates the location of a core sample at a given infiltration time t. The corresponding signal amplitude, Indicates the initial time The sum of the T2 spectrum signal corresponding to the entire core, i.e. the oil content of the entire core. This represents the total T2 spectral signal intensity of the entire core at an absorption time t, which is equivalent to the oil content of the entire core. This represents the difference in oil content throughout the entire core during the spontaneous infiltration time period t. The spontaneous absorption performance determination unit is used to determine the spontaneous absorption performance of each core segment based on the spontaneous absorption efficiency and spontaneous absorption contribution rate.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method described in any one of claims 1-5.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1-5.

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