Method for determining change in nanoscale pore structure, and use thereof

Abstract

Disclosed are a method for determining a change in a nanoscale pore structure, and the use thereof. The determination method comprises: a, putting a nanoscale pore structure sample which has been subj

Description

[0002] The present disclosure relates to a method for determining a change in a nanoscale pore structure and use thereof. BACKGROUND ART

[0003] With growing global energy demand and continually improving oil and gas exploitation technology, tight oil and gas resources have become the focus of exploration and exploitation in many countries. The occurrence and seepage of petroleum and natural gas mainly take place in the nanoscale pore and fracture system in tight reservoirs (e.g., shale cores obtained during drilling and extraction). Therefore, it is of great significance for the exploration and exploitation of tight oil and gas to carry out effective and reasonable evaluation and determination for the pore and fracture system of tight reservoirs.

[0004] A porous medium is composed of many pores and a solid matrix in which the pores develop. A specific surface area of a porous medium is the total area of the porous medium per unit of mass. A pore volume is the total volume of pores in a porous medium per unit of mass. A pore size distribution refers to percentages of different levels of pore sizes in a porous medium calculated by number or volume. Microscopic pores of a porous medium may be divided into micropores (<2 nm), mesopores (2-50 nm), and macropores (including pores and fractures of >50 nm). Existing experimental methods for pore characterization of a porous medium include a low temperature nitrogen adsorption method, a mercury intrusion method, etc. Principally, these methods may directly reflect some characteristics of microscopic pores in a porous medium by measured parameters such as the specific surface area, the pore volume and the pore size distribution. A tight reservoir is a porous medium. On the basis of the existing experimental methods for pore characterization, usually the characterization parameters of the microscopic pores in the tight reservoir may be measured under different under experimental conditions, such as different lithological characters, different mesh numbers, and different temperatures and pressures, and compared in transverse and longitudinal directions, thereby indirectly reflecting the influences of different experimental conditions on the microscopic pore structure of the tight reservoir. At present, some typical rock mechanical parameters, such as Young modulus and Poisson's ratio, are often used to evaluate the difficulty level of fracture development in a tight reservoir. However, the above-mentioned methods all overlook errors in qualitative and quantitative researches on microscopic pores of tight reservoirs caused by changes in the pore structure during sample preparation. Therefore, it is of great significance to establish a method capable of determining microscopic pore structure changes of nanoscale pores in a tight reservoir occurring in the structural damage process. SUMMARY Technical Problem

[0005] The present disclosure provides a method for determining a change in a nanoscale pore structure and use thereof. Solutions for the problems Technical solutions

[0006] A method for determining a change in a nanoscale pore structure includes the following steps:

[0007] a, putting a vacuum-degassed sample having a nanoscale pore structure into liquid nitrogen, detecting a nitrogen adsorption quantity of the sample under a plurality of preset pressure values P to obtain an isothermal adsorption curve showing changes of the nitrogen adsorption quantity of the sample with a relative pressure P / Po, where Po is a saturated vapor pressure of nitrogen at an adsorption temperature;

[0008] b, selecting the isothermal adsorption curve within a range of O.O5<P / Po<O.35, obtaining a nitrogen volume Vm needed by monolayer adsorption based on a slope s and an intercept i; calculating a specific surface area (SSA) of the sample by utilizing a Brunauer-Emmett-Teller (BET) specific surface area formula SSA=(Vmxo) / 22400 W, where o is a sectional area of an adsorbed gas, and W is a mass of the vacuum-degassed sample;

[0009] c, calculating volumes of micropores, mesopores and macropores by a non-local density functional theory (NLDFT) method, respectively, and then obtaining a sum and PV of the volumes of the micropores, the mesopores and the macropores in the sample and a change trend of PV with a pulverizing mesh number; and

[0010] d, calculating the values of SSA / PV under different pulverized particle sizes of the sample, and determining the influence of a pulverizing process on the nanoscale pore structure according to an increasing change trend of the value of SSA / PV with a pulverizing mesh number.

[0011] As an embodiment, a temperature for vacuum degassing in step a ranges from 90°C to 120°C.

[0012] As an embodiment, the vacuum degassing in step a lasts for greater than or equal to 9 h.

[0013] As an embodiment, step b may specifically include selecting an isothermal adsorption curve within a range of O.O5<P / Po<O.35 and obtaining the nitrogen volume Vm needed by monolayer adsorption based on the slope s and the intercept i. The selection of the isothermal adsorption curve within the above range can help further reduce the error of the determination method.

[0014] As an embodiment, in step b, a relationship of the Vm to the slope s and the intercept i is: Vm=l / (s+i). A relationship of Vm to the slope s of the isothermal adsorption curve within the range of O.O5<P / Po<O.35 is: s=(C-l) / (Vm*C), where C is a BET constant. A relationship of Vm to the intercept i of the isothermal adsorption curve within the range of O.O5<P / Po<O.35 is: i=l / (Vm><C), where C is a BET constant. Thus, the following formula is derived: Vm=l / (s+i).

[0015] As an embodiment, step c may specifically include selecting values within a range of O.Ol<P / Po<O.995 and obtaining the volumes of the micropores, the mesopores and the macropores from statistics of ASiQ software by the NLDFT method.

[0016] As an embodiment, step d may specifically include determining the change in the nanoscale pore structure in the sample based on the changes of the value of SSA / PV when the pulverized particle size of the sample ranges from 20 mesh to 200 mesh.

[0017] The present disclosure further provides use of the determination method in determining the influence of a sample preparation damage process on a nanoscale pore structure of a tight reservoir. The method for determining a change in a nanoscale pore structure provided in the present disclosure can qualitatively determine microscopic pore structure changes of nanoscale pores in a tight reservoir occurring in the structural damage (sample pulverizing) process based on the changes in SSA / PV of the sample under different pulverized particle sizes by characterizing the parameters such as the specific surface area, the pore volume and the pore size diameter of the microscopic pores of tight rock. Thus, errors of research results caused by changes in the pore structure during sample preparation in traditional methods of qualitative and quantitative researches on nanoscale pores of tight reservoirs can be avoided. If the value of SSA / PV changes significantly with changing pulverizing mesh number, it can be determined that the sample preparation damage process has different degrees of influences on the nanoscale pore structure of the tight reservoir.

[0018] The present disclosure further provides use of the determination method in determining the accuracy of pore structure test characterization data of a tight reservoir sample having a nanoscale pore structure. The magnitude of an error can be determined based on the magnitude of the change rate of SSA / PV, and then the error can be corrected. Thus, the accuracy of the traditional methods of qualitative and quantitative researches on nanoscale pores of tight reservoirs can be improved.

[0019] As an embodiment, when the pulverized particle size of the sample ranges from 20 mesh to 200 mesh, the value of SSA / PV decreases and a correlation coefficient R2 of the value of SSA / PV changing with the pulverizing mesh number is more than or equal to 0.6, indicating that the pore structure test characterization data of the tight reservoir sample having a nanoscale pore structure has a certain error and needs to be corrected. A correlation coefficient R2 may differ for the values of SSA / PV of different samples changing with a pulverizing mesh number, indicating that the value of SSA / PV is also related to the pore type of the sample. The occurrence and seepage of petroleum and natural gas mainly take place in the nanoscale pore and fracture system in a tight reservoir. When the pulverized particle size of the sample ranges from 20 mesh to 200 mesh, the value of SSA / PV decreases and a correlation coefficient R2 of the value of SSA / PV changing with the pulverizing mesh number is more than or equal to 0.6, indicating that an error existing in traditional detection of the pore structure test characterization data of the tight reservoir would affect or even mislead the effective and reasonable evaluation and determination on the pore and fracture system in the tight reservoir, which may go against the effective exploration and exploitation of oil and gas resources. Beneficial Effects of the Present Disclosure Beneficial effects

[0020] As provided in the present disclosure, an isothermal adsorption curve showing changes of the nitrogen adsorption quantity with the relative pressure P / Po is established. The isothermal adsorption within the range of O.O5<P / Po<O.35 is selected, and the nitrogen volume Vm needed by monolayer adsorption is calculated. The specific surface area (SSA) of the sample is then calculated by the BET specific surface area formula. Thus, highly accurate SSA values of the sample under different pulverizing mesh numbers can be obtained. By the NLDFT method, critical P / Po values for micropores, mesopores and macropores are separately collected, so as to obtain the volumes of the micropores, the mesopores and the macropores. Thus, the changes of the volumes of different types of pores in the sample with increasing pulverized particle size are obtained. Finally, the change in the nanoscale pore structure is determined based on the changes of SSA / PV of the sample under different pulverized particle sizes.

[0021] The determination method provided in the present disclosure can accurately detect the SSA and total PV values of the sample under different pulverized particle sizes, and can not only determine the influence of the sample preparation damage process on the nanoscale pore structure in the tight reservoir sample but also accurately determine errors of research results caused by changes in the pore structure during sample preparation in traditional methods of qualitative and quantitative researches on nanoscale pores of tight reservoirs. In short, the determination method is of great significance for the exploration and exploitation of tight oil and gas resources. BRIEF DESCRIPTION OF THE DRAWINGS Description of drawings

[0022] FIG. 1 is a diagram illustrating an isothermal adsorption curve of sample 1 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0023] FIG. 2 is a diagram illustrating an isothermal adsorption curve of sample 2 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0024] FIG. 3 is a diagram illustrating an isothermal adsorption curve of sample 3 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0025] FIG. 4 is a diagram illustrating an isothermal adsorption curve of sample 4 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0026] FIG. 5 is a diagram illustrating an isothermal adsorption curve of sample 5 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0027] FIG. 6 is a diagram illustrating an isothermal adsorption curve of sample 6 under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0028] FIG. 7 is a diagram illustrating a change curve of SSA values of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0029] FIG. 8 is a diagram illustrating an increase rate curve of SSA of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0030] FIG. 9 is a diagram illustrating a change curve of volumes of micropores of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0031] FIG. 10 is a diagram illustrating a change curve of volumes of mesopores of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0032] FIG. 11 is a diagram illustrating a change curve of volumes of macropores of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0033] FIG. 12 is a diagram illustrating a change curve of PV values of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0034] FIG. 13 is a diagram illustrating an increase rate curve of PA values of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure.

[0035] FIG. 14 is a diagram illustrating a change curve of values of SSA / PV of 6 samples under different pulverizing mesh numbers in an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] Embodiments

[0037] 1. Device

[0038] Low temperature nitrogen adsorption apparatus

[0039] 2. Samples

[0040] Shale rock cores are obtained by well drilling, and 6 shale rock core samples are selected, each pulverized into 20 mesh, 80 mesh, and 200 mesh.

[0041] 3. Determination method

[0042] The samples are vacuum-degassed at a temperature of 100°C for 9 h. The mass W of each vacuum-degassed sample is obtained by calculating a difference between the mass of a tube holding the sample after the degassing and the mass of the empty tube before the degassing. The degassed sample is put into liquid nitrogen, and the nitrogen adsorption quantities of the sample under a plurality of preset pressure points are detected to obtain the isothermal adsorption curve of the sample. The isothermal adsorption curves of 6 samples under different pulverizing mesh numbers are as shown in FIG. 1 to FIG. 6.

[0043] The isothermal adsorption curve within a range of 0.1<P / Pq<0.3 is selected, and the nitrogen volume Vm needed by monolayer adsorption is obtained based on a slope s and an intercept i: Vm=l / (s+i). The specific surface area (SSA) of the sample is calculated by utilizing the BET specific surface area formula SSA=(Vmxo) / 22400 W, where g is the sectional area of the adsorbed gas, and W is the mass of the vacuum-degassed sample. The SSA values of 6 samples calculated under different pulverizing mesh numbers are as shown in Table 1, and the change curve of the SSA values of 6 samples under different pulverizing mesh numbers is as shown in FIG. 7.

[0044] Table 1 SSA Values of 6 Samples Under Different Pulverizing Mesh Numbers [Table 1] Sample No. SSA Value (m2 / g) 20 Mesh SSA Value (m2 / g) 80 Mesh SSA Value (m2 / g) 200 Mesh 1 6.897 6.778 6.471 2 8.168 7.223 6.748 3 4.414 7.384 7.212 4 8.18 9.993 6.185 5 2.703 2.186 2.387 6 4.09 4.99 4.413

[0045] Increments and increase rates of SSA of 6 samples with increasing pulverizing mesh number are calculated from the SSA values of the samples under different pulverizing mesh numbers in Table 1. The calculation results are as shown in Table 2, and the increase rate curve of SSA is as shown in FIG. 8.

[0046] Table 2 Increments and Increase Rates of SSA [Table 2] ____________________________________________________________________________ Sample No. Increment of SSAUnder 20-80 Mesh Increment of SSA Under 80-200 Mesh Increase Rate of SSA Under 20-80 Mesh Increase Rate of SSA Under 80-200 Mesh 1 -0.119 -0.307 -1.73% -4.53% 2 -0.945 -0.475 -11.57 -6.58% 3 2.790 -0.172 67.29% -2.33% 4 1.813 -3.808 22.16% -38.11% 5 -0.517 0.201 -19.13% 9.19% 6 0.900 -0.577 22.00% -11.56%

[0047] Values within the range of O.Ol<P / Po<O.995 are selected, and the volumes of the micropores, the mesopores and the macropores in the sample are obtained from statistics of ASiQ software by the NLDFT method, whereby the total PV of the micropores, the mesopores and the macropores in the sample is obtained. In this manner, the volumes and the total PV values of the micropores, the mesopores and the macropores of 6 samples under different pulverizing mesh numbers are calculated. The calculated volume values of the micropores, the mesopores and the macropores are as shown in Table 3. The volume change curve of the micropores is as shown in FIG. 9, while the volume change curve of the mesopores is as shown in FIG. 10 and the volume change curve of the macropores is as shown in FIG. 11. The calculated total PV values are as shown in Table 4, and the change curve of the PV values is as shown in FIG. 12.

[0048] Table 3 Volumes of Micropores, Mesopores and Macropores [Table 3] Sample No. Pulverizing Mesh Number Volume cc / g of Micropores Volume cc / g of Mesopores Volume cc / g of Macropores 1 20 0.00261 0.012181 0.003309 1 80 0.002831 0.013422 0.010147 1 200 0.002505 0.01237 0.006675 2 20 0.003489 0.011512 0.003069 2 80 0.002907 0.014975 0.012348 2 200 0.002646 0.016932 0.016272 3 20 0.001684 0.003281 0.002929 3 80 0.002899 0.011326 0.014595 3 200 0.002899 0.015749 0.013612 4 20 0.003625 0.0047156 0.0029594 4 80 0.003898 0.012406 0.022646 4 200 0.0025 0.019966 0.022064 5 20 0.0007351 0.0032649 0.000752 5 80 0.0007948 0.0052052 0.00671 5 200 0.0008545 0.0054411 0.0066644 6 20 0.001542 0.0054033 0.0017597 6 80 0.001916 0.010672 0.013082 6 200 0.001712 0.012501 0.017957

[0049] Table 4 Total PV values of 6 Samples Under Different Pulverizing Mesh Numbers [Table 4]____________________________________________________________________________ Sample No. PV Value (cc / g) 20 Mesh PV Value (cc / g) 80 Mesh PV Value (cc / g) 200 Mesh 1 0.018100 0.026400 0.02155 2 0.018070 0.030230 0.03585 3 0.007894 0.028820 0.03226 4 0.011300 0.038950 0.04453 5 0.004752 0.012710 0.01296 6 0.008705 0.025670 0.03217

[0050] Increments and increase rates of PV of 6 samples with increasing pulverizing mesh number are calculated from the total PV values of the samples under different pulverizing mesh numbers in Table 3. The calculation results are as shown in Table 5, and the increase rate curve of PV of 6 samples with increasing pulverizing mesh number is plotted, as shown in FIG. 13.

[0051] Table 5 Increments and Increase Rates of PV [Table 5] Sample Increment of PV Increment of PV Increase Rate of PV Increase Rate of PV No. Under 20-80 Mesh Under 80-200 Mesh Under 20-80 Mesh Under 80-200 Mesh 1 0.008300 -0.004850 45.86% -18.37% 2 0.012160 0.005620 67.29% 18.59% 3 0.020926 0.003440 265.09% 11.94% 4 0.027650 0.005580 244.69% 14.33% 5 0.007958 0.000250 167.47% 1.97% 6 0.016965 0.006500 194.89% 25.32%

[0052] As can be seen from the data in Tables 1 and 2 and Tables 4 and 5, and FIG. 7, FIG. 8, FIG. 12 and FIG. 13, changes in SSA and PV in the pore and fracture system of the rock samples with the pulverizing mesh number of the samples increasing from 20 mesh to 80 mesh and then to 200 mesh are as follows:

[0053] 1) SSA does not change a lot, and PV increases greatly. Under experimental conditions, the pulverizing process of the shale rock sample from 20 mesh to 80 mesh and then to 200 mesh causes only a small change in the micropores in the rock sample. The content of the micropores does not change a lot. During sample preparation, the quantity of the mesopores and the macropores in the sample increases with increasing pulverizing mesh number. The increase in the quantity of the macropores may be attributed to: a, the mesopores being damaged and the pores being communicated into the macropores; and b, new fractures being formed such that the previously closed pores are communicated with one another.

[0054] 2) In the pulverizing process from 80 mesh to 200 mesh, the increase rate of PV changes a little as compared with that in the process from 20 mesh to 80 mesh. The damage to the shale rock sample caused by the pulverizing process from 20 mesh to 80 mesh results in a significant increase in communicated pores in the pore and fracture system, causing the PV values to increase significantly. In the damage process from 80 mesh to 200 mesh to the shale rock sample, a few communicated pores are formed, and the micropores do not change a lot. In other words, in the pulverizing process from 20 mesh to 80 mesh, the pore structure of the shale rock sample is basically damaged, and no more new pores and fractures can be formed by continuous pulverization.

[0055] Therefore, with increasing pulverizing mesh number in the sample pulverizing preparation process, new communicated pores are formed in the shale rock sample, and these communicated pores are opened through added micro-fractures. However, such an increasing trend does not continue all through. When the pulverized particle size reaches a particular value, the increase amplitude of the pore volume of the sample is reduced. At this time, the microscopic pore structure of the shale rock sample is basically damaged, resulting in no more pores and fractures formed.

[0056] 3) Statistical analysis is performed on SSA / PV data, and the results are as shown in Table 6.

[0057] Table 6 SSA / PV Values and Change Rates of Samples from 20 Mesh to 80 Mesh and to 200 Mesh [Table 6] ___________________________________________________________________________________ Sample No. SSA / PV Under 20 Mesh SSA / PV Under 80 Mesh SSA / PV Under 200 Mesh Increase Rate of SSA / PV Under 20-80 Mesh Increase Rate of SSA / PV Under 80-200 Mesh 6 381.0497 256.7424 300.2784 -32.6223% 16.9571% 13 452.0199 238.9348 188.2287 -47.1406% -21.2217% 25 559.1589 256.2110 223.5586 -54.1792% -12.7443% 44 723.8938 256.5597 138.8951 -64.5584% -45.8625% 46 568.8131 171.9906 184.1821 -69.7633% 7.0885% 52 469.8449 194.3903 137.1775 -58.6267% -29.4319%

[0058] Change curves of SSA / PV of 6 samples between 80 mesh and 200 mesh are plotted based on the data in Table 6. The change curves of SSA / PV are as shown in FIG. 14.

[0059] From Table 6 and FIG. 14, in the process of increasing the pulverizing mesh number of the sample from 20 mesh to 80 mesh and then to 200 mesh, the value of SSA / PV has a certain correlation to the pulverizing mesh number (with R2 changing within a range of 0.6-0.8), and SSA / PV has a decreasing trend with the pulverizing mesh number. This indicates that the increase of the pulverizing mesh number leads to an increase in communicated pores in the pore system during sample preparation, resulting in formation of new pores and fractures. As a result, the pore volume increases, and damage is caused to the nanoscale pore structure of the shale rock core. The comparison of change rates of SSA / PV values of different types of samples may show that the degree of sample preparation damage causes great errors of traditional pore structure test characterization data, which may affect the results of oil and gas exploration. Thus, the related characterization data needs to be corrected.

[0060] The above detection results further verify the feasibility of using the changes of SSA / PV with the mesh number to determine the change in the microscopic pore structure of the tight reservoir during sample preparation and to determine the accuracy of the accuracy of the pore structure test characterization data of the tight reservoir sample having the nanoscale pore structure.

[0061] The foregoing are merely descriptions of the preferred embodiment of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

17 10241. A method for determining a change in a nanoscale pore structure, comprising the following steps:a, putting a vacuum-degassed sample having a nanoscale pore structure into liquid nitrogen, detecting a nitrogen adsorption quantity of the sample under a plurality of preset pressure values P to obtain an isothermal adsorption curve showing changes of the nitrogen adsorption quantity of the sample with a relative pressure P / Po, the Po being a saturated vapor pressure of nitrogen at an adsorption temperature;b, selecting the isothermal adsorption curve within a range of O.O5<P / Po<O.35, obtaining a nitrogen volume Vm needed by monolayer adsorption based on a slope s and an intercept i; calculating a specific surface area (SSA) of the sample by utilizing a Brunauer-Emmett-Teller (BET) specific surface area formula SSA=(Vmxo) / 22400 W, wherein o is a sectional area of an adsorbed gas, and W is a mass of the vacuum-degassed sample;c, calculating volumes of micropores, mesopores and macropores by a non-local density functional theory (NLDFT) method, respectively, and then obtaining a sum PV of the volumes of the micropores, the mesopores and the macropores in the sample; andd, calculating the values of SSA / PV under different pulverized particle sizes of the sample, and determining the influence of a pulverizing process on the nanoscale pore structure according to an increasing change trend of the value of SSA / PV with a pulverizing mesh number;correcting pore structure test characterization data of the sample having a nanoscale pore structure with an error, when the pulverized particle size of the sample ranges from 20 mesh to 200 mesh, and the value of SSA / PV decreases and a correlation coefficient R2 of the value of SSA / PV changing with the pulverizing mesh number ranges from 0.6 to 0.8.

2. The method according to claim 1, wherein a temperature for vacuum degassing in step a ranges from 90°C to 120°C.

3. The method according to claim 1, wherein the vacuum degassing in step a lasts for greater than or equal to 9 h.

4. The method according to claim 1, wherein step b specifically comprises selecting an isothermal adsorption curve within a range of 0. l<P / Po<O.3 and obtaining the nitrogen volume Vm needed by monolayer adsorption based on the slope s and the intercept i.

5. The method according to claim 1, wherein in step b, a relationship of the Vm to the slope sand the intercept i is: Vm=l / (s+i).17 10246. The method according to claim 1, wherein step c specifically comprises selecting values within a range of O.Ol<P / Po<O.995 and obtaining the volumes of the micropores, the mesopores and the macropores by the NLDFT method.

7. The method according to claim 1, wherein step d specifically comprises determining the change in the nanoscale pore structure in the sample based on the changes of the value of SSA / PV when the pulverized particle size of the sample ranges from 20 mesh to 200 mesh.

8. Use of the method for determining a change in a nanoscale pore structure according to any one of claims 1 to 7 in determining the influence of a sample preparation damage process on a nanoscale pore structure of a tight reservoir.

9. Use of the method for determining a change in a nanoscale pore structure according to any one of claims 1 to 7 in determining the accuracy of pore structure test characterization data of a tight reservoir sample having a nanoscale pore structure.

10. The use according to claim 9, wherein when the pulverized particle size of the sample ranges from 20 mesh to 200 mesh, the value of SSA / PV decreases and a correlation coefficient R2 of the value of SSA / PV changing with the pulverizing mesh number is more than or equal to 0.6, indicating that the pore structure test characterization data of the tight reservoir sample having a nanoscale pore structure has an error and needs to be corrected.

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