Method and device for determining relaxation rate of rock surface and computing equipment

Abstract

The invention discloses a method and a device for determining the relaxation rate of a rock surface and computing equipment. The method comprises the following steps: acquiring a rock core serving as a sample; acquiring basic data of the rock core; calculating the specific surface area of the rock core based on the basic data of the rock core, and recording rock core mass in a rock core saturation state; the rock core is subjected to multiple times of centrifugal treatment, the rock core mass after each time of centrifugation and the T2 cutoff value after each time of centrifugation are recorded, and the mass difference between the rock core mass when the rock core is in the saturated state and the rock core mass after each time of centrifugal treatment is calculated; fitting the mass difference after each centrifugal treatment with the corresponding T2 cut-off value to obtain the T2 cut-off value of the rock core in a saturated state; and calculating the surface relaxation rate of the rock core based on the specific surface area of the rock core and the T2 cut-off value of the rock core in the saturated state. According to the method, the surface relaxation rate of the rock is determined by combining the low-field nuclear magnetic instrument and the specific surface area instrument, so that the surface relaxation rate of the heterogeneous sandstone is measured more accurately, simply and conveniently.

Description

Technical Field

[0001] The present invention relates to a method for determining the relaxation rate of a rock surface, and in particular to a method, a device, a computing device and a computer storage medium for determining the relaxation rate of a rock surface. Background Art

[0002] Among various rocks, the heterogeneity of sandstone is a common characteristic of oil reservoirs. As a common and important reservoir type, the accurate determination of its physical properties is extremely critical for the evaluation and production of oil and gas reservoirs. However, the existing average value method and specific surface area method widely used to determine the rock surface relaxation rate have many shortcomings.

[0003] The characteristic of the average value method is that it is based on the consideration of the overall physical properties of the core. It assumes that the core is a relatively uniform system, and uses the relationship between macroscopic physical quantities to deduce the surface relaxation rate. Its calculation parameters need to be determined by the average pore radius of the core through the mercury injection method. This method can only obtain an average result, and cannot consider the differences in surface relaxation rates caused by factors such as different positions and different pore structures inside the core. The pore structure inside the core is often complex and diverse, so this method cannot accurately describe the local characteristics of the core. Therefore, the average value method is more suitable for the measurement of large-pore cores with strong homogeneity, and has great limitations for inhomogeneous cores. In addition to the principle, the most prominent problem in actual measurement is that the mercury injection experiment requires mercury to be continuously injected into the core at different pressures, so it will cause irreversible damage to the core, and the risks of mercury to the environment and human health are unpredictable.

[0004] The specific surface area method determines the specific surface area of ​​the core through a gas absorption experiment, and then calculates the surface relaxation rate of the core by comparing and analyzing it with the logarithmic average value of T2. Its principle can better take into account the influence of microscopic factors inside the core on the relaxation process, and is more suitable for cores with tiny pore structures. However, this principle is based on the assumption that the surface properties of the core are uniform, while the actual core surface often has changes in mineral composition, roughness, etc., so the calculated value of the surface relaxation rate will have a large deviation. In addition, the gas adsorption method for measuring the specific surface area requires grinding the core, which also causes damage to the rock sample. Moreover, the experimental operation is relatively complicated and requires high experience and ability of the experimenter, which also leads to uncertainty in the experimental results.

[0005] Therefore, a simple, efficient and environmentally friendly method is urgently needed to determine the relaxation rate of heterogeneous rock surfaces to meet the ever-evolving needs of geological exploration and oil and gas resource development and provide more powerful technical support for research and practice in related fields. Summary of the invention

[0006] In view of the above problems, the present invention is proposed to provide a method, apparatus, computing device and computer storage medium for determining the relaxation rate of a rock surface that overcome the above problems or at least partially solve the above problems.

[0007] According to one aspect of the present invention, there is provided a method for determining a relaxation rate of a rock surface, the method comprising:

[0008] Obtaining rock cores as samples;

[0009] Obtain basic data of cores;

[0010] Calculate the core specific surface area based on the core basic data and record the core mass when the core is in a saturated state;

[0011] The core was centrifuged several times, and the core mass after each centrifugation and the T after each centrifugation were recorded. 2截止值 , calculate the mass difference between the core mass at saturation and the core mass after each centrifugation treatment;

[0012] The mass difference after each centrifugation treatment is compared with the corresponding T 2截止值 After fitting, the T of the core in saturated state is obtained. 2截止值 ;

[0013] Based on the core specific surface area and the T 2截止值 Calculate the surface relaxation rate of the core.

[0014] In an optional embodiment, obtaining a core as a sample further comprises: washing oil, washing salt and drying the selected core to obtain a core as a sample;

[0015] Obtaining the basic data of the core further includes: measuring the diameter and length of the core, and calculating the cross-sectional area of ​​the core.

[0016] In an optional embodiment, calculating the core specific surface area based on the basic data of the core and recording the core mass when the core is in a saturated state further includes:

[0017] The specific surface area meter is used to measure some parameters used to calculate the specific surface area of ​​the core, including: the viscosity of the gas passing through the core, the flow rate of the gas passing through the core, and the height difference of the water column at both ends of the core at the flow rate;

[0018] Use a vacuum pressurized saturation device to saturate the core and record the core mass when it is in a saturated state;

[0019] Use a low-field nuclear magnetic resonance to scan the saturated core and calculate the core porosity;

[0020] The core specific surface area is calculated based on the core basic data, core porosity and some parameters.

[0021] In an optional embodiment, the multiple centrifugation treatments on the core further include:

[0022] The saturated core is centrifuged multiple times using a constant temperature centrifuge, wherein the centrifugal speed range is: 3000-5000 rpm, and the single centrifugation time is 5-20 minutes.

[0023] In an optional embodiment, the T after each centrifugation is recorded. 2截止值 Further including:

[0024] The T2 spectrum corresponding to each centrifugation treatment was measured using a low-field nuclear magnetic resonance instrument to obtain the T 2截止值 .

[0025] In an optional embodiment, the mass difference after each centrifugation is compared with the corresponding T 2截止值 After fitting, the T of the core in saturated state is obtained. 2截止值 Further including:

[0026] The mass difference after each centrifugation treatment Δm i The corresponding T 2截止值 Perform linear fitting processing, the specific formula is:

[0027] f(Δm i )=kΔm i +t

[0028] Where, f(Δm i ) is Δm i The corresponding T 2截止值 , k and t are the parameters to be fitted;

[0029] When Δm i =0, f(Δm i ) on the y-axis is the T value of the core in the saturated state. 2截止值 .

[0030] In an optional embodiment, based on the core specific surface area and the T of the core in a saturated state, 2截止值 Calculation of the surface relaxation rate of the core further includes:

[0031] According to the formula Calculate the surface relaxation rate of the core, where ρ is the surface relaxation rate, S b is the core specific surface area, T 2cutoff is the T of the core in saturated state 2截止值 .

[0032] According to another aspect of the present invention, there is provided an apparatus for determining a relaxation rate of a rock surface, comprising:

[0033] An acquisition module is used to acquire a core as a sample and obtain basic data of the core;

[0034] A first calculation module is used to calculate the specific surface area of ​​the core based on the basic data of the core;

[0035] A centrifugal processing module, used for performing multiple centrifugal processing on the core;

[0036] The recording module is used to record the core mass when the core is in a saturated state, the core mass after each centrifugal treatment, and the T after each centrifugal treatment. 2截止值 ;

[0037] The second calculation module is used to calculate the mass difference between the core mass in the saturated state and the core mass after each centrifugation treatment, and to compare the mass difference after each centrifugation treatment with the corresponding T 2截止值 The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 ;

[0038] The third calculation module is used to calculate the core specific surface area and the T of the core in a saturated state. 2截止值 Calculate the surface relaxation rate of the core.

[0039] According to another aspect of the present invention, there is provided a computing device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus;

[0040] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned method for determining the relaxation rate of the rock surface.

[0041] According to another aspect of the present invention, a computer storage medium is provided, in which at least one executable instruction is stored, and the executable instruction enables a processor to perform operations corresponding to the above-mentioned method for determining the relaxation rate of a rock surface.

[0042] According to the method, device, computing device and computer storage medium for determining the relaxation rate of the rock surface of the present invention, a core is obtained as a sample; basic data of the core is obtained; the specific surface area of ​​the core is calculated based on the basic data of the core, and the core mass when the core is in a saturated state is recorded; the core is centrifuged for multiple times, and the core mass after each centrifugation and the T after each centrifugation are recorded. 2截止值 , calculate the mass difference between the core mass at saturation and the core mass after each centrifugation; compare the mass difference after each centrifugation with the corresponding T 2截止值The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 ; Based on the core specific surface area and the core T in saturated state 2截止值 Calculate the surface relaxation rate of the core. The present invention provides a method for accurately and easily determining the surface relaxation rate of heterogeneous rocks (such as sandstone) by combining a low-field nuclear magnetic analyzer and a specific surface area meter. The experimental process is quick and the calculation process is simple. It is not affected by the pore structure of the core, will not damage the core, and will not threaten the environment and personnel health. It provides important rock physical parameters for reservoir evaluation and oil and gas development, helps to deeply understand the reservoir pore structure and fluid distribution characteristics, and provides a scientific basis for improving oil and gas recovery.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0045] Figure 1 A schematic flow chart of a method for determining a rock surface relaxation rate according to Embodiment 1 of the present invention is shown;

[0046] Figure 2 The figure shows the core quality difference and T according to the first embodiment of the present invention. 2截止值 A coordinate diagram for graphically fitting the measurement results;

[0047] Figure 3 A schematic structural diagram of a device for determining a rock surface relaxation rate according to a second embodiment of the present invention is shown; and

[0048] Figure 4 A schematic diagram of the structure of a computing device provided according to a fourth embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0050] In the technical solution of the present invention, a simple, efficient and environmentally friendly method for determining the surface relaxation rate of rocks (especially for heterogeneous sandstones) is provided by using a low-field nuclear magnetic analyzer and a specific surface area analyzer. The principle is to assume that the fluid in the core cannot be driven (this assumption is a macroscopic physical property assumption and does not affect the microscopic properties) and is bound fluid. 2截止值 Alternative T 2对数平均值 The surface relaxation rate of the core is calculated using the relationship between relaxation time, specific surface area and surface relaxation rate.

[0051] Figure 1 FIG. 4 is a flow chart of a method for determining the relaxation rate of a rock surface according to Embodiment 1 of the present invention. Figure 1 As shown, the method includes:

[0052] Step S110, obtaining a core as a sample.

[0053] Specifically, the selected cores are subjected to oil washing, salt washing and drying treatments to obtain cores as samples, to remove residual impurities in the cores, to maintain the purity of the cores in their initial state, and to provide stable samples for subsequent experiments.

[0054] Step S120, obtaining basic data of the core.

[0055] Specifically, obtaining the basic data of the core includes measuring the diameter and length of the core, calculating the cross-sectional area of ​​the core, etc. Among them, the cross-sectional area A of the core is calculated by the formula: A = πd 2 / 4; where A is the cross-sectional area of ​​the core, in square centimeters; d is the diameter of the core, in centimeters;

[0056] To facilitate experimental measurement, it is preferred to select a cylindrical core of universal size, and the size of the core is determined according to the capacity of commonly used equipment. Preferably, the diameter of the core is generally 1 inch or 2 inches, and the length does not exceed 10 centimeters. The specific shape and size of the core can be determined according to actual conditions and is not limited here.

[0057] Step S130, calculating the core specific surface area based on the basic data of the core, and recording the core mass when the core is in a saturated state.

[0058] Specifically, a specific surface area meter is used to measure some parameters used to calculate the specific surface area of ​​the core, and some parameters include: the viscosity of the gas passing through the core, the flow rate of the gas passing through the core, and the height difference of the water column at both ends of the core at the flow rate. Preferably, in this embodiment, the core gas is nitrogen, and the Mallott bottle method is used to measure the specific surface area of ​​the core, which not only maintains the integrity, reusability and repeatability of the core, but also ensures the effective use of experimental data and the continuity of the entire process. In this embodiment, the gas adsorption method is not used to measure the specific surface area because the experimental method is complicated to operate and requires the destruction of the core, and the subsequent nuclear magnetic resonance experimental steps cannot be completed.

[0059] The core is saturated with a vacuum pressure saturation device, and water with appropriate salinity and pressure are selected to saturate the core to eliminate the effects of water sensitivity and stress sensitivity on the core pore structure.

[0060] Record the core mass when the core is in a saturated state to provide basic data for subsequent fitting calculations and to evaluate the relationship between the core mass difference after centrifugation and T 2截止值 relationship.

[0061] Use a low-field nuclear magnetic resonance to scan the saturated core and calculate the core porosity. Preferably, in this embodiment, a Newmai 150 low-field nuclear magnetic resonance is selected to scan the water-saturated core, and the core porosity is obtained by the peak point method or the area method. According to the basic data of the core, the core porosity and some parameters, the core specific surface area is calculated. The method of this embodiment uses the principle of nuclear magnetic resonance to determine the core porosity value, and calculates T 2截止值 to ensure the convenience of experimental operation.

[0062] In this example, the specific surface area S of the core before saturation with water is calculated. b , the calculation formula is:

[0063]

[0064] Among them, S b is the core specific surface area, in centimeters -1 ; φ is the porosity of the core, in decimal; A is the cross-sectional area of ​​the core, in square centimeters; L is the length of the core, in centimeters; Q is the gas flow rate through the core, in cubic centimeters per second; H is the height difference of the water column at both ends of the core corresponding to the flow rate Q, in centimeters; μ is the viscosity of the gas passing through the core, in Pa-seconds.

[0065] Step S140, centrifuge the core several times, and record the core mass after each centrifugation and the T after each centrifugation. 2截止值 , calculate the mass difference between the core mass when the core is in a saturated state and the core mass after each centrifugation treatment.

[0066] Calculate the difference between the mass of the core after saturation and the mass after each centrifugation, Δm i =m0-m i (where i is the number of centrifugation times, and 3≤i),

[0067] Among them, Δm i is the mass difference between the saturated and centrifuged core, in grams; m0 is the mass of the saturated core, in grams; m i is the mass of the core after centrifugation, in grams.

[0068] Specifically, the saturated core was centrifuged multiple times using a constant temperature centrifuge, wherein the centrifugal speed range and the single centrifugal time can be set according to specific needs. In this embodiment, the centrifugal speed range is set to 3000-5000 rpm, and the single centrifugal time is 5-20 minutes. After each centrifugation, the core was weighed and recorded, and the T2 spectrum corresponding to each centrifugal treatment was measured using a low-field nuclear magnetic resonance instrument to obtain T 2截止值 After multiple centrifugation treatments, the mass difference and the corresponding T 2截止值 It can better fit the linear relationship and provide accurate values ​​for the subsequent calculation of rock surface relaxation rate.

[0069] Step S150, comparing the mass difference after each centrifugation with the corresponding T 2截止值 After fitting, the T of the core in saturated state is obtained. 2截止值 .

[0070] The mass difference after each centrifugation treatment Δm i The corresponding T 2截止值 Perform linear fitting processing, the specific formula is:

[0071] f(Δm i )=kΔm i +t

[0072] Where, f(Δm i ) is Δm i The corresponding T 2截止值 , k and t are the parameters to be fitted;

[0073] When Δm i =0, f(Δm i ) on the y-axis is the T value of the core in the saturated state. 2截止值 . Due to T 2截止值 It represents the boundary between movable fluid and bound fluid in the core, so the T of the core in the saturated state is 2截止值 It is impossible to measure and obtain, therefore, it is assumed that all the fluid in the core under saturation is bound fluid, and then the T under this state is deduced through the fitting formula. 2截止值, and then calculate the rock surface relaxation rate.

[0074] Step S160, based on the core specific surface area and the T of the core in a saturated state 2截止值 Calculate the surface relaxation rate of the core.

[0075] Specifically, according to the formula Calculate the surface relaxation rate of the core, where ρ is the surface relaxation rate, S b is the core specific surface area, T 2cutoff is the T of the core in saturated state 2截止值 .

[0076] The method for determining the rock surface relaxation rate of this embodiment will be described below through specific examples.

[0077] First, obtain the core as a sample. Specifically, wash the oil, salt and dry the selected core, and measure the basic parameters of the core. Secondly, calculate. In this example, the length L of the core is 4.980 cm, and the diameter d is 2.516 cm. According to the core cross-sectional area formula, the cross-sectional area A of the core is 4.9693 square centimeters. Thirdly, use a specific surface area meter to measure and calculate the parameters of the specific surface area of ​​the core. In this example, the measuring gas is nitrogen, and the viscosity coefficient μ is 0.0000. 175 Pa·s, the gas flow rate Q through the core is 0.1712 cubic centimeters / second, the height difference H of the water column at both ends of the core under this flow rate is 68 cm, the core is vacuumed and saturated using a vacuum saturation device, and the mass m0 of the saturated core is measured to be 56.7611g. The saturated core is scanned using a Newmai 150 low-field nuclear magnetic spectrometer, and the core porosity φ is obtained by the peak point method to be 11.51%, which is converted to a decimal place of 0.1151, and S is calculated according to the core specific surface area calculation formula b is 2940.1075 cm -1 Finally, the core was centrifuged 10 times at a speed of 5000 rpm for 5-10 minutes. The mass after each centrifugation was recorded and the mass difference and the corresponding T were calculated. 2截止值 , the data are shown in Table 1:

[0078] Table 1

[0079]

[0080] According to the mass difference and T 2截止值 The measurement results are fitted graphically, such as Figure 2 shown.

[0081] Among them, the fitting graph formula is: f(Δm i )=-123.61Δm i +294.1, when Δmi When it is equal to 0, the T of the saturated core 2截止值 It is 294.1 milliseconds.

[0082] According to the formula The surface relaxation rate of the core was calculated to be 11.56 μm / s.

[0083] According to the method for determining the surface relaxation rate of rock in this embodiment, by combining a low-field nuclear magnetic resonance instrument and a specific surface area meter, a method for accurately and conveniently determining the surface relaxation rate of heterogeneous rock (such as sandstone) is provided. The method has a quick experimental process, a simple calculation process, is not affected by the core pore structure, will not damage the core, and will not threaten the environment and personnel health. It provides important rock physical parameters for reservoir evaluation and oil and gas development, helps to deeply understand the reservoir pore structure and fluid distribution characteristics, and provides a scientific basis for improving oil and gas recovery.

[0084] Embodiment 2

[0085] Figure 3 FIG. 3 is a functional structure diagram of a device 300 for determining a rock surface relaxation rate according to a second embodiment of the present invention. Figure 3 As shown, the device 300 includes: an acquisition module 310, a first calculation module 320, a centrifugal processing module 330, a recording module 340, a second calculation module 350 and a third calculation module 360.

[0086] An acquisition module 310 is used to acquire a core as a sample and acquire basic data of the core;

[0087] A first calculation module 320, used to calculate the core specific surface area based on the basic data of the core;

[0088] A centrifugal processing module 330 is used to perform multiple centrifugal processing on the core;

[0089] The recording module 340 is used to record the core mass when the core is in a saturated state, the core mass after each centrifugation process, and the T value after each centrifugation process. 2截止值 ;

[0090] The second calculation module 350 is used to calculate the mass difference between the core mass in the saturated state and the core mass after each centrifugation treatment, and compare the mass difference after each centrifugation treatment with the corresponding T 2截止值 The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 ;

[0091] The third calculation module 360 ​​is used to calculate the core specific surface area based on the core T in the saturated state. 2截止值 Calculate the surface relaxation rate of the core.

[0092] In an optional embodiment, the acquisition module 310 is further used to wash the selected cores with oil, salt and dry them to obtain the cores as samples; measure the diameter and length of the cores, and calculate the cross-sectional area of ​​the cores.

[0093] In an optional embodiment, the first calculation module 320 is further used to use a specific surface area meter to determine some parameters used to calculate the specific surface area of ​​the core, and the some parameters include: the viscosity of the gas passing through the core, the flow rate of the gas passing through the core, and the height difference of the water column at both ends of the core at the flow rate; the recording module is further used to saturate the core using a vacuum pressurized saturation device, and record the core mass when the core is in a saturated state; the first calculation module is further used to use a low-field nuclear magnetic resonance instrument to scan the saturated core and calculate the core porosity; the core specific surface area is calculated based on the basic data of the core, the core porosity and some parameters.

[0094] In an optional embodiment, the centrifugal treatment module 330 is further used to perform multiple centrifugal treatments on the saturated core using a constant temperature centrifuge, wherein the centrifugal speed range is: 3000-5000 rpm, and the single centrifugation time is 5-20 minutes.

[0095] In an optional embodiment, the recording module 340 is further used to measure the T2 spectrum corresponding to each centrifugation treatment using a low-field nuclear magnetic resonance instrument to obtain T 2截止值 .

[0096] In an optional embodiment, the second calculation module 350 is further configured to calculate the mass difference Δm after each centrifugation treatment. i The corresponding T 2截止值 Perform linear fitting processing, the specific formula is:

[0097] f(Δm i )=kΔm i +t

[0098] Where, f(Δm i ) is Δm i The corresponding T 2截止值 , k and t are the parameters to be fitted;

[0099] When Δm i =0, f(Δm i ) on the y-axis is the T value of the core in the saturated state. 2截止值 .

[0100] In an optional implementation, the third calculation module 360 ​​is further configured to calculate Calculate the surface relaxation rate of the core, where ρ is the surface relaxation rate, S bis the core specific surface area, T 2cutoff is the T of the core in saturated state 2截止值 .

[0101] It can be seen that according to the device for determining the surface relaxation rate of rock in this embodiment, by combining a low-field nuclear magnetic resonance instrument and a specific surface area meter, a device is provided for accurately and conveniently determining the surface relaxation rate of heterogeneous rock (such as sandstone). The experimental process is fast, the calculation process is simple, it is not affected by the pore structure of the core, will not cause damage to the core, and will not pose a threat to the environment and personnel health. It provides important rock physical parameters for reservoir evaluation and oil and gas development, helps to deeply understand the reservoir pore structure and fluid distribution characteristics, and provides a scientific basis for improving oil and gas recovery.

[0102] Embodiment 3

[0103] According to a third embodiment of the present invention, a non-volatile computer storage medium is provided. The computer storage medium stores at least one executable instruction. The computer executable instruction can execute the method in any of the above method embodiments.

[0104] Embodiment 4

[0105] Figure 4 A schematic diagram of the structure of a computing device provided according to Embodiment 4 of the present invention is shown. The specific embodiment of the present invention does not limit the specific implementation of the computing device.

[0106] like Figure 4 As shown, the computing device may include: a processor (processor) 402 , a communications interface (Communications Interface) 404 , a memory (memory) 406 , and a communication bus 408 .

[0107] The processor 402, the communication interface 404, and the memory 406 communicate with each other via the communication bus 408. The communication interface 404 is used to communicate with other devices such as a client or other server network elements. The processor 402 is used to execute the program 410, which can specifically execute the relevant steps in the above method embodiment.

[0108] Specifically, the program 410 may include program codes, which include computer operation instructions.

[0109] The processor 402 may be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The one or more processors included in the computing device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0110] The memory 406 is used to store the program 410. The memory 406 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0111] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0112] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: that the claimed invention requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0113] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0114] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0115] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A method for determining the relaxation rate of a rock surface, characterized in that The method comprises: Obtaining rock cores as samples; Acquiring basic data of the core; Calculating the core specific surface area based on the basic data of the core, and recording the core mass of the core in a saturated state; The core was centrifuged several times, and the core mass after each centrifugation and the T after each centrifugation were recorded. 2截止值 , calculating the mass difference between the core mass of the core in a saturated state and the core mass after each centrifugation treatment; The mass difference after each centrifugation treatment is compared with the corresponding T 2截止值 The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 ; Based on the specific surface area of ​​the core and the T 2截止值 The surface relaxation rate of the core was calculated.

2. The method according to claim 1, characterized in that The obtaining of the core as a sample further comprises: washing the selected core with oil, washing the salt and drying the core to obtain the core as a sample; The obtaining of the basic data of the core further includes: measuring the diameter and length of the core, and calculating the cross-sectional area of ​​the core.

3. The method according to claim 1, characterized in that The calculating the core specific surface area based on the basic data of the core and recording the core mass of the core in a saturated state further includes: Using a specific surface area meter to measure some parameters used to calculate the specific surface area of ​​the core, the parameters include: viscosity of the gas passing through the core, flow rate of the gas passing through the core, and height difference of water columns at both ends of the core at the flow rate; Utilizing a vacuum pressurized saturation device to saturate the core, and recording the core mass of the core in a saturated state; Use a low-field nuclear magnetic resonance to scan the saturated core and calculate the core porosity; The core specific surface area is calculated according to the basic data of the core, the core porosity and the partial parameters.

4. The method according to claim 1, characterized in that: The centrifugal treatment of the core for multiple times further comprises: The saturated core is centrifuged multiple times using a constant temperature centrifuge, wherein the centrifugal speed range is: 3000-5000 rpm, and the single centrifugation time is 5-20 minutes.

5. The method according to claim 1, characterized in that Record the T after each centrifugation 2截止值 Further including: The T2 spectrum corresponding to each centrifugation treatment was measured using a low-field nuclear magnetic resonance instrument to obtain the T 2截止值 .

6. The method according to claim 1, characterized in that The mass difference after each centrifugation treatment is compared with the corresponding T 2截止值 The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 Further including: The mass difference after each centrifugation treatment Δm i The corresponding T 2截止值 Perform linear fitting processing, the specific formula is: f(Δm i )=kΔm i +t Where, f(Δm i ) is Δm i The corresponding T 2截止值 , k and t are the parameters to be fitted; When Δm i =0, f(Δm i ) on the y-axis is the T value of the core in the saturated state. 2截止值 .

7. The method according to claim 1, characterized in that The core specific surface area and the T of the core in a saturated state are 2截止值 Calculating the surface relaxation rate of the core further comprises: According to the formula The surface relaxation rate of the core is calculated, where ρ is the surface relaxation rate, S b is the core specific surface area, T 2cutoff is the T of the core in saturated state 2截止值 .

8. A device for determining the relaxation rate of a rock surface, characterized in that: The device comprises: An acquisition module, used to acquire a rock core as a sample and acquire basic data of the rock core; A first calculation module, used for calculating the core specific surface area based on the basic data of the core; A centrifugal processing module, used for performing multiple centrifugal processing on the core; The recording module is used to record the core mass of the core in a saturated state, the core mass after each centrifugal treatment, and the T after each centrifugal treatment. 2截止值 ; The second calculation module is used to calculate the mass difference between the core mass in the saturated state and the core mass after each centrifugation treatment, and compare the mass difference after each centrifugation treatment with the corresponding T 2截止值 The fitting process is performed to obtain the T of the core in the saturated state. 2截止值 ; The third calculation module is used to calculate the core specific surface area and the T of the core in a saturated state based on the core specific surface area and the T of the core in a saturated state. 2截止值 The surface relaxation rate of the core was calculated.

9. A computing device comprising: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the method for determining the relaxation rate of a rock surface as described in any one of claims 1-7.

10. A computer storage medium, wherein at least one executable instruction is stored in the storage medium, and the executable instruction enables a processor to perform operations corresponding to the method for determining the relaxation rate of a rock surface as described in any one of claims 1 to 7.

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