阅读说明：本技术 一种利用核磁共振测量岩心物性的方法 (Method for measuring physical properties of rock core by using nuclear magnetic resonance ) 是由 杨培强 张政 燕军 华帅 陈会会 朱莹莹 于 2020-07-27 设计创作，主要内容包括：本发明公开了一种利用核磁共振测量岩心物性的方法,包括调试核磁共振参数；将现场取得的岩心迅速进行新鲜样品取样,进行核磁共振新鲜样测量；进行饱水处理,进行核磁共振饱水样测量；测量样品的质量、体积和密度；将样品冷冻后粉碎；将样品与过量饱和氯化锰溶液混合后密封,放入核磁共振设备进行核磁共振饱猛样测量；分别进行核磁共振水定标和油定标；对测试结果进行数据处理,得到岩心物性。与传统方法相比,本发明准确性高,稳定性好,同时检测速度快,成本低,适用于各种环境下现场岩心物性的快速检测。(The invention discloses a method for measuring the physical property of a rock core by utilizing nuclear magnetic resonance, which comprises the steps of debugging nuclear magnetic resonance parameters; rapidly sampling a fresh sample of the rock core obtained on site, and measuring the fresh sample by nuclear magnetic resonance; carrying out water saturation treatment, and carrying out nuclear magnetic resonance water saturation sample measurement; measuring the mass, volume and density of the sample; freezing and crushing a sample; mixing the sample with an excessive saturated manganese chloride solution, sealing, and placing into a nuclear magnetic resonance device for measuring the saturated sample of the nuclear magnetic resonance; respectively carrying out nuclear magnetic resonance water calibration and oil calibration; and (4) carrying out data processing on the test result to obtain the physical property of the rock core. Compared with the traditional method, the method has the advantages of high accuracy, good stability, high detection speed and low cost, and is suitable for rapidly detecting the physical properties of the core on site in various environments.)

1. A method for measuring the physical property of a rock core by utilizing nuclear magnetic resonance is characterized by comprising the following steps:

s1: taking a rock core sample, carrying out nuclear magnetic resonance fresh sample measurement, and measuring a fresh sample T₂A spectrogram;

s2: carrying out water saturation treatment on the rock core sample, then carrying out nuclear magnetic resonance water saturation sample measurement, and measuring a water saturation sample T₂A spectrogram;

s3: measuring the mass, volume and density of the saturated water sample;

s4: freezing the saturated water sample and then crushing;

s5: performing manganese saturation treatment on the crushed sample, then performing nuclear magnetic resonance manganese saturation sample measurement, and measuring a manganese saturation sample T₂A spectrogram;

s6: respectively carrying out nuclear magnetic resonance water calibration and oil calibration;

s7: and (4) carrying out data processing on the test result to obtain the physical property of the rock core.

2. The method for measuring the physical properties of the core as recited in claim 1, wherein the measured indicators of the physical properties of the core are one or more of nuclear magnetic porosity, oil saturation, original water saturation, loss, SDR permeability and pore size distribution.

3. The method for measuring core properties according to claim 2,

the nuclear magnetic porosity (%): phi is a_nmr＝(V_{Total water}+V_{Total oil})/V_{Sample (I)}×100％；

The original water saturation (%): s_w＝V_{Original water}/(V_{Total water}+V_{Total oil})×100％；

The escape amount (%): s_{Loss of function}＝V_{Escape water}/(V_{Total water}+V_{Total oil})×100％；

The oil saturation (%): and S. Is equal to V_{Total oil}/(V_{Total water}+V_{Total oil})×100％；

Wherein said V_{Total water}Is saturated with water sample total water volume, V_{Total oil}Is the total oil volume, V, of the core sample_{Sample (I)}Is a water-saturated volume, V_{Original water}Total water volume, V, of core sample before saturation_{Escape water}The total water volume of the water saturated sample-the total water volume of the core sample before water saturation.

4. The method for measuring core properties according to claim 2, wherein the SDR permeability:wherein, T_2gIs nuclear magnetic resonance T₂Geometric mean value, C_s1The model parameters are different according to the rock sample of the corresponding region.

5. The method of measuring core properties according to claim 2, wherein the pore size distribution comprises a median pore size radius: r is_c＝ρ₂×T₂X 3, wherein, T₂For transverse relaxation time, p₂Is the transverse surface relaxation strength of the rock.

6. The method for measuring the physical properties of the core as claimed in claim 1, wherein the water saturation treatment in step S2 is to immerse a fresh sample in water for 1-2 hours, and remove surface floating water after taking out.

7. The method for measuring core properties according to claim 1, wherein the sample is frozen by using liquid nitrogen in step S4 for 5-10min, and then crushed into pieces with a particle size of 1mm or less;

in the saturated manganese treatment in the step S5, the sample is mixed with an excessive saturated manganese chloride solution for 1-2 hours and then sealed.

8. The method for measuring the physical properties of the core according to any one of claims 1 to 7, wherein the water calibration in step S6 is to prepare a series of standard nuclear magnetic resonance samples with different volumes of water, perform the nuclear magnetic resonance measurement on each standard sample, prepare a nuclear magnetic water calibration curve after measuring the nuclear magnetic resonance signal, and obtain a standard curve equation;

the oil calibration is to prepare a series of nuclear magnetic resonance standard samples of crude oil with different volumes by using the crude oil on site, perform nuclear magnetic resonance measurement on each standard sample, prepare a nuclear magnetic oil calibration curve after measuring a nuclear magnetic resonance signal, and obtain a standard curve equation of the nuclear magnetic oil calibration curve.

9. The method for measuring core properties according to claim 8, wherein the series of nmr standard samples of different volumes of water is 0.01ml, 0.03ml, 0.05ml, 0.07ml, 0.1ml of water;

the series of nuclear magnetic resonance standard samples of crude oil with different volumes are 0.01ml, 0.03ml, 0.05ml, 0.07ml and 0.1ml of crude oil.

10. The method for measuring physical properties of a core as claimed in claim 1, wherein the mass, volume and density are measured using a density balance in step S3.

Technical Field

The invention relates to the field of core physical property detection, in particular to a method for measuring core physical property by utilizing nuclear magnetic resonance.

Background

According to the requirements of geological exploration work or engineering, a cylindrical rock sample, namely a rock core, is taken out from a hole by using an annular rock core drill and other coring tools. The core is important physical geological data for researching and knowing underground geology and mineral production conditions, and the physical parameters to be measured by the core comprise T₂Relaxation spectrum, porosity, permeability, pore size distribution and oil saturation;

the prior art can be divided into direct measurements (laboratory measurements) and indirect measurements (various geophysical logging methods), however both methods have disadvantages.

The laboratory measurement method applied to the coring site mainly has the following problems:

1. time cost is high, test results are delayed: the laboratory measurement needs on-site coring and sending the core to the laboratory for measurement, the sample treatment and measurement period is long, the measurement result lag can reach 1 month, and the requirement of rapidly obtaining physical property parameters on site cannot be met;

2. the method has the advantages that the sample quantity requirement is high, the sample loss is large, the transportation and storage of the sample are difficult, different experiments are needed for measuring various parameters, the sample quantity is high, and the core coring loss is large;

3. the loss of oil, gas and water of the sample is reduced, and the result truth is reduced, namely the loss of oil, gas and water is large in the process from the site to the laboratory of the rock core, and the oil saturation obtained in the laboratory has large deviation;

4. the measurement cost is high, and the laboratory measurement experiment has various types, and the cost is very high when a large quantity of samples are tested by encryption coring.

Geophysical logging methods have the following difficulties:

1. the underground logging measurement conditions are greatly different from the laboratory measurement conditions, such as pressure, temperature, measurement device principle and the like, and meanwhile, a large amount of data processing is needed, so that artificial errors can be caused;

2. the underground geophysical logging cannot simultaneously obtain a plurality of correlated physical parameters;

3. the measurement of downhole logging requires large wireline logging or measurement-while-drilling equipment, which is very costly.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is that the direct measurement method for the physical property of the core in the prior art cannot rapidly measure, has high cost and poor stability, so that the method for measuring the physical property of the core by using nuclear magnetic resonance is provided.

Therefore, the invention adopts the following technical scheme:

the invention provides a method for measuring the physical property of a rock core by utilizing nuclear magnetic resonance, which comprises the following steps:

s1: taking a rock core sample, carrying out nuclear magnetic resonance fresh sample measurement, and measuring a fresh sample T₂A spectrogram;

s2: carrying out water saturation treatment on the rock core sample, then carrying out nuclear magnetic resonance water saturation sample measurement, and measuring a water saturation sample T₂A spectrogram;

s3: measuring the mass, volume and density of the saturated water sample;

s4: freezing the saturated water sample and then crushing;

s5: performing manganese saturation treatment on the crushed sample, then performing nuclear magnetic resonance manganese saturation sample measurement, and measuring a manganese saturation sample T₂A spectrogram;

s6: respectively carrying out nuclear magnetic resonance water calibration and oil calibration;

s7: and (4) carrying out data processing on the test result to obtain the physical property of the rock core.

Furthermore, the measurement indexes of the physical properties of the rock core are one or more of nuclear magnetic porosity, oil saturation, original water saturation, escaping quantity, SDR permeability and pore size distribution.

Further, the air conditioner is provided with a fan,

the nuclear magnetic poreDegree (%): phi is a_nmr＝(V_{Total water}+V_{Total oil})/V_{Sample (I)}×100％；

The original water saturation (%): s_w＝V_{Original water}/(V_{Total water}+V_{Total oil})×100％；

The escape amount (%): s_{Loss of function}＝V_{Escape water}/(V_{Total water}+V_{Total oil})×100％；

The oil saturation (%): and S. Is equal to V_{Total oil}/(V_{Total water}+V_{Total oil})×100％；

Wherein said V_{Total water}Is saturated with water sample total water volume, V_{Total oil}Is the total oil volume, V, of the core sample_{Sample (I)}Is a water-saturated volume, V_{Original water}Total water volume, V, of core sample before saturation_{Escape water}The total water volume of the water saturated sample-the total water volume of the core sample before water saturation.

The SDR permeability is as follows:wherein, T_2gIs nuclear magnetic resonance T₂Geometric mean value, C_s1The model parameters are different according to the rock sample of the corresponding region.

The pore size distribution includes a median pore diameter radius: r is_c＝ρ₂×T₂X 3, wherein, T₂For transverse relaxation time, p₂Is the transverse surface relaxation strength of the rock.

Preferably, the water saturation treatment in step S2 is to soak a fresh sample in water for 1-2 hours, and wipe off the surface floating water after taking out.

In step S4, the sample is frozen by using liquid nitrogen for 5-10min, and then the sample is crushed into fragments with the particle size of less than 1 mm.

In the saturated manganese treatment in the step S5, the sample is mixed with an excessive saturated manganese chloride solution for 1-2 hours and then sealed.

The water calibration in the step S6 is to prepare a series of nuclear magnetic resonance standard samples of water with different volumes, nuclear magnetic resonance measurement is carried out on each standard sample, a nuclear magnetic water calibration curve is prepared after a nuclear magnetic resonance signal is measured, and a standard curve equation of the nuclear magnetic water calibration curve is obtained;

the oil calibration is to prepare a series of nuclear magnetic resonance standard samples of crude oil with different volumes by using the crude oil on site, perform nuclear magnetic resonance measurement on each standard sample, prepare a nuclear magnetic oil calibration curve after measuring a nuclear magnetic resonance signal, and obtain a standard curve equation of the nuclear magnetic oil calibration curve.

Further, the series of nmr standard samples containing different volumes of water are 0.01ml, 0.03ml, 0.05ml, 0.07ml, 0.1ml of water;

the series of nuclear magnetic resonance standard samples of crude oil with different volumes are 0.01ml, 0.03ml, 0.05ml, 0.07ml and 0.1ml of crude oil.

Mass, volume and density were measured using a density balance in step S3.

The technical scheme of the invention has the following advantages:

(1) compared with the traditional measuring method, the method has the advantages that the core which is just taken out of the barrel on site is directly used for carrying out rapid nuclear magnetic resonance detection, the fluid escape of the core is small, the measured result is the closest to the original formation physical property parameters, the accuracy is high, meanwhile, the method directly collects the nuclear magnetic resonance signal of the hydrogen-containing fluid in the sample, the resolution ratio of the hydrogen-containing fluid can reach 1mg, the nuclear magnetic resonance signal of the hydrogen-containing fluid can be directly converted into the fluid volume after the standard sample is calibrated, and further, the parameters such as the porosity, the oil saturation, the pore size distribution and the like of the sample are obtained.

(2) The nuclear magnetic resonance test system has good stability of test results, the nuclear magnetic resonance equipment is used for measuring the physical property of the rock core, the nuclear magnetic resonance equipment adopts a permanent magnet and is additionally provided with a shielding shell, the magnet is provided with an independent temperature control module and can keep constant temperature operation at 32 ℃, the host machine adopts an industrial control computer to ensure long-time operation stability, all the equipment can work cooperatively and stably to ensure the stability of the test results under the complex working condition on site, meanwhile, for a sample with the same depth, the nuclear magnetic resonance measurement can be carried out by taking a plurality of parallel samples, the measurement results have good consistency, and the nuclear magnetic resonance test system can be usedIn the same sample, the magnetic resonance can be performed by continuous multiple nuclear magnetic resonance T₂And (4) measuring the spectrum, wherein the deviation of the measurement result of the total nuclear magnetic resonance signal is less than 1%.

(3) The invention greatly reduces the measurement time, and in the nuclear magnetic resonance test, the single nuclear magnetic T₂The spectrum measurement can be completed only in 2-3 min; the on-site rapid sampling is carried out, and the sampling is carried out immediately after the core is taken out of the barrel, so that the minimum fluid loss of the core can be ensured, and the extra water saturation time is reduced; the saturated manganese is crushed after freezing, manganese ions in the powder sample can be diffused completely more quickly and more quickly, and the saturated manganese time is shortened; all links of the whole testing process are buckled, the time consumption for measuring a large number of samples is short, the conventional field coring is taken as an example, and the whole experimental process can be completed in 4 hours on the field.

(4) The invention utilizes the density balance to accurately measure the mass, the volume and the density of the irregular sample, and solves the problem that the conventional method can only measure the regular standard sample; the sample is broken after being frozen, so that the fluid escape in the sample breaking process is avoided; the manganese ions are diffused into the pores more quickly and completely after the sample is broken, and the steps increase the preparation in the testing process, so that the final testing result is more reliable.

(5) The invention uses low-field nuclear magnetic resonance equipment, adopts a 0.5T permanent magnet, has no radiation, is safe to operate and harmless to human bodies, generates no harmful substances in the experimental process, and is economic and environment-friendly; in the field rapid test, only conventional experimental instruments and medicines such as a glass chromatographic bottle, a glass test tube, distilled water, liquid nitrogen, clean alcohol and the like are used, and the whole operation flow is safe and environment-friendly and has no dangerous operation; the equipment and the experiment can meet the test conditions in the on-site board room, and the requirement on the environment is not harsh.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method for measuring the physical properties of a core by using nuclear magnetic resonance in examples 1 and 2 of the present invention;

FIG. 2 is a nuclear magnetic resonance spectrum of sample 1 in example 1 of the present invention;

FIG. 3 is a nuclear magnetic resonance water calibration curve in examples 1 and 2 of the present invention;

FIG. 4 is a nuclear magnetic resonance oil calibration curve in examples 1 and 2 of the present invention;

FIG. 5 is a nuclear magnetic resonance spectrum of sample 2 in example 1 of the present invention;

FIG. 6 is a graph showing a relationship between a pore size distribution and a pore size volume ratio of sample 1 in test example 1 of the present invention;

FIG. 7 is a graph of pore size distribution versus porosity component for sample 1 in test example 1 of the present invention;

FIG. 8 is a histogram of pore size distribution versus pore size volume ratio of sample 1 in test example 1 of the present invention;

FIG. 9 is a cumulative distribution diagram of pore diameters of sample 1 in test example 1 of the present invention;

FIG. 10 is a graph showing a relationship between a pore size distribution and a pore size volume ratio of sample 2 in test example 1 of the present invention;

FIG. 11 is a graph of pore size distribution versus porosity component for sample 2 in test example 1 of the present invention;

FIG. 12 is a histogram of pore size distribution versus pore size volume ratio of sample 2 in test example 1 of the present invention;

FIG. 13 is a cumulative distribution diagram of pore diameters of sample 2 in test example 1 of the present invention;

FIG. 14 is a nuclear magnetic resonance spectrum of sample A1 in test example 2 of the present invention;

FIG. 15 is a nuclear magnetic resonance spectrum of sample A1-1 in test example 2 of the present invention;

FIG. 16 is a nuclear magnetic resonance spectrum of sample A2 in test example 2 of the present invention;

FIG. 17 is a nuclear magnetic resonance spectrum of sample A2-1 in test example 2 of the present invention;

FIG. 18 is a nuclear magnetic resonance spectrum of sample B1 in test example 2 of the present invention;

FIG. 19 is a nuclear magnetic resonance spectrum of sample B2 in test example 2 of the present invention.

Detailed Description

The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.

The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field.

The reagents and instruments used in the present invention were as follows: the micro MR20-0.25V nuclear magnetic resonance instrument is produced by Nymei analytical instruments of Suzhou, the resonance frequency of the instrument is 20.0MHz, the magnet strength is 0.47T, the diameter of a probe coil is 25mm, and the temperature of the magnet is controlled at 32 ℃;

samples 1 and 2 and samples A1, A1-1, A2, A2-1, B1 and B2 in the test examples are all taken from the northern part of the Songliao basin, a section of the Qingshan Kou group;

the rest of the reagents are all standard reagents in the market.

The following specific examples are further illustrative of the present invention, and the examples do not exemplify all the embodiments of the present invention, but only some of the embodiments are exemplified, and the specific examples are as follows:

example 1

The embodiment provides a method for measuring the physical property of a core by using nuclear magnetic resonance, as shown in fig. 1, the specific steps are as follows:

(1) opening a nuclear magnetic resonance analyzer, calibrating frequency, searching pulse width, and setting parameters in analysis software as follows:

SEQ：CPMG；

SF(MHz)：18

O1(Hz)：183676.54；

P1(us)：6.60；

TD：60020；

PRG：3；

TW(ms)：2000.000；

P2(us)：14.00；

T_E(ms)：0.150；

NECH：2000；

SW(KHz)：200；

RFD(ms)：0.080；

RG1(db)：20.0；

DRG1：3；

DR：1

NS：32；

(2) trimming a rock core sample 1 obtained on site by using pliers and scissors, wrapping the rock core sample with a raw material belt, putting the raw material belt into a test tube with the specification of 25mm x 220mm, and performing fresh sample nuclear magnetic resonance measurement to obtain a fresh sample T₂Nuclear magnetic spectrum;

(3) and removing the raw material belt, putting the sample 1 into a sample bag, pouring distilled water to immerse the sample for water saturation treatment, wherein the water saturation time is 1 hour. Taking out the sample 1, slightly wiping off the floating water on the surface of the sample by using toilet paper, coating the sample by using a raw material tape, putting the sample into a test tube for carrying out saturated sample nuclear magnetic resonance measurement, and obtaining a saturated sample T₂Nuclear magnetic spectrum;

(4) taking out the saturated water sample, removing the raw material belt, and measuring the mass m of 12.21g and the volume V of the sample by using a density balance_{Sample (I)}＝4.83cm³And the density rho is 2.52g/cm³；

(5) Putting the saturated water sample into a liquid nitrogen tank, freezing the sample 1 for 5min by using liquid nitrogen, and then quickly breaking and grinding the sample in a special grinding dish to obtain fragments with the particle size of less than 1 mm;

(6) pouring 1000ml of distilled water into a 2000ml beaker, adding 800g of manganese chloride powder into the water, stirring by using a glass rod, fully dissolving, standing, and pouring a supernatant into the beaker to obtain a saturated manganese chloride solution;

(7) pouring the crushed sample 1 into a nuclear magnetic sealed sample injection bottle, pouring saturated manganese chloride solution with about twice the volume of the sample, sealing, oscillating, fully mixing, standing for 2 hours, putting into a nuclear magnetic resonance device for performing the nuclear magnetic resonance measurement of the saturated manganese sample to obtain a saturated manganese sample T₂Nuclear magnetic spectrum, step (2) (3)

(7) The spectrum results are shown in FIG. 2;

(8) taking 0.01ml, 0.03ml, 0.05ml, 0.07ml and 0.1ml of water as water standard samples, respectively, carrying out nuclear magnetic resonance measurement on each water standard sample under the same test parameters, taking the volume of the water in the nuclear magnetic resonance standard samples as an abscissa and the nuclear magnetic resonance signals of the standard samples as an ordinate, drawing a scatter diagram, wherein the data are shown in a table 1:

TABLE 1 NMR Water calibration data

Amount of water ml	Water standard nuclear magnetic signal a.u.
		0.01	437.2998
0.03	1312.651
		0.05	2173.141
0.07	3050.109
		0.1	4352.745

And (3) making a nuclear magnetic water marking line, and performing a unitary linear regression equation to obtain a standard curve equation for converting the nuclear magnetic resonance water signal into the water volume as shown in figure 3: 43492x + 3.5883;

(9) taking 0.01ml, 0.03ml, 0.05ml, 0.07ml and 0.1ml of field crude oil as oil standard samples, carrying out nuclear magnetic resonance measurement on each oil standard sample under the same test parameters, drawing a scatter diagram by taking the volume of oil in the nuclear magnetic resonance standard sample as an abscissa and the nuclear magnetic resonance signal of the standard sample as an ordinate, wherein the data table is shown in table 2:

TABLE 2 NMR oil calibration data

Volume ml of oil	Oil standard nuclear magnetic signal a.u.
		0.01	159.200
0.03	477.600
		0.05	796.000
0.07	1114.400
		0.1	1592.000

Making a nuclear magnetic oil marking line, and as shown in fig. 4, performing a unary linear regression equation to obtain a standard curve equation for converting a nuclear magnetic resonance oil signal into an oil volume; 15920 x.

Example 2

The embodiment provides a method for measuring the physical property of a core by using nuclear magnetic resonance, as shown in fig. 1, the specific steps are as follows:

(1) opening a nuclear magnetic resonance analyzer, calibrating frequency, searching pulse width, and setting parameters in analysis software as follows:

SEQ：CPMG；

SF(MHz)：18

O1(Hz)：183676.54；

P1(us)：6.60；

TD：60020；

PRG：3；

TW(ms)：2000.000；

P2(us)：14.00；

T_E(ms)：0.150；

NECH：2000；

SW(KHz)：200；

RFD(ms)：0.080；

RG1(db)：20.0；

DRG1：3；

DR：1

NS：32；

(2) trimming the core sample 2 obtained on site by using pliers and scissors, wrapping the core sample with a raw material tape, putting the coated core sample into a test tube with the specification of 25mm x 220mm, and performing fresh sample nuclear magnetic resonance measurement to obtain a fresh sample T₂Nuclear magnetic spectrum;

(3) and removing the raw material belt, putting the sample 2 into a sample bag, pouring distilled water to immerse the sample for water saturation treatment, wherein the water saturation time is 2 hours. Taking out the sample 2, slightly wiping off the floating water on the surface of the sample by using toilet paper, coating the sample by using a raw material belt, putting the sample into a test tube for carrying out saturated sample nuclear magnetic resonance measurement, and obtaining a saturated sample T₂Nuclear magnetic spectrum;

(4) taking out the saturated water sample, removing the raw material belt, and measuring the mass m of 10.59g and the volume V of the sample by using a density balance_{Sample (I)}＝4.32cm³Density rho is 2.45g/cm³；

(5) Putting the saturated water sample into a liquid nitrogen tank, freezing the sample 2 for 10min by using liquid nitrogen, and then quickly breaking and grinding the sample in a special grinding dish to obtain fragments with the particle size of less than 1 mm;

(6) pouring 1000ml of distilled water into a 2000ml beaker, adding 800g of manganese chloride powder into the water, stirring by using a glass rod, fully dissolving, standing, and pouring a supernatant into the beaker to obtain a saturated manganese chloride solution;

(7) pouring the crushed sample 2 into a nuclear magnetic sealed sample injection bottle, pouring saturated manganese chloride solution with about twice the volume of the sample, sealing, oscillating, fully mixing, standing for 1 hour, and placing into a nuclear magnetic resonance device for performing the nuclear magnetic resonance measurement of the saturated manganese sample to obtain a saturated manganese sample T₂Nuclear magnetic spectrum, step (2) (3)

(7) The spectrum results are shown in FIG. 5;

(8) (9) same as example 1.

Test example 1

The data measured in examples 1 and 2 were processed as follows:

1. porosity calculation was performed:

the total water semaphore of the sample is water saturation semaphore-manganese saturation semaphore;

the total oil signal amount of the sample is the saturated manganese-like signal amount;

the sample escaping water loss semaphore is the saturated water-like semaphore-fresh-like semaphore;

the original water content semaphore of the sample is fresh-saturated manganese semaphore;

the semaphore data is shown in table 3:

TABLE 3 NMR semaphoric data

Numbering	Water saturation signal	Fresh sample signal volume	Signal quantity of saturated manganese
				Example 1	6651.720298	4769.026303	2150.493551
Example 2	10473.49703	7704.751128	2336.826323

The volumes of water and oil were then calculated according to the scaling equation obtained in the example,

the total water signal quantity of the sample is according to a water calibration equation: and y is 43492x +3.5883, and the total water signal quantity is substituted into y to obtain x, namely the total water volume V of the sample_{Total water}；

The sample escaping water signal quantity is according to the water calibration equation: and y is 43492x +3.5883, and the escaping water signal quantity is substituted into y to obtain x, namely the escaping water volume V of the sample_{Escape water}；

The original water content signal quantity of the sample is according to a water calibration equation: and y is 43492x +3.5883, and the original water content signal quantity is substituted into y to obtain x, namely the original water volume V of the sample_{Original water}；

The total oil signal amount of the sample is according to an oil calibration equation: 15920x, the oil signal is substituted into y to obtain x, i.e. the oil volume V_{Total oil}；

Nuclear magnetic porosity (%): phi is a_nmr＝(V_{Total water}+V_{Total oil})/V_{Sample (I)}×100％。

Original water saturation (%): s_w＝V_{Original water}/(V_{Total water}+V_{Total oil})×100％。

Amount of escape (%): s_{Loss of function}＝V_{Escape water}/(V_{Total water}+V_{Total oil})×100％。

2. And (3) calculating the oil saturation:

oil saturation (%): and S. Is equal to V_{Total oil}/(V_{Total water}+V_{Total oil})×100％。

SDR permeability:

SDR model: by nuclear magnetismPorosity (phi)_nmr)、T₂Geometric mean (T)_2g) Calculating the nuclear magnetic permeability;

in the formula, T_2gIs nuclear magnetic resonance T₂Geometric mean, ms; t is_2iIs the ith NMR transverse relaxation time, ms; phi is a_iAs a corresponding component T_2iThe porosity component,%; phi is a_nmrNuclear magnetic porosity value of sample,%; n is nuclear magnetic resonance T₂Number of samples of the spectrum.

Model parameter C_s1The calculation is carried out by formula statistical analysis;

in the formula:

K₁nuclear magnetic permeability of the SDR model in millidarcy (10)^-3μm²)；

C_s1Model parameters, determined by statistical analysis of experimental measurements of the rock sample in the corresponding region, for samples 1 and 2, C_s1＝200000。

4. Pore size distribution:

transverse relaxation time of hydrogen nuclei in rock pores:

in the formula, T₂Transverse relaxation time, ms; t is_2BIs the volume (free) relaxation time of the fluid, ms; d is the diffusion coefficient, μm²(ms); g is magnetic field gradient, gauss/cm; t is_EIs the echo interval, ms; s is the surface area of the pores; v is the volume of the pores; rho₂Is the transverse surface relaxation strength of the rock, μm/ms. γ is the magnetic spin ratio, which is the ratio between the magnetic moment and the angular momentum of a spin nucleus (spin nuclear).

T_2BThe value of (A) is usually 2-3s, to T₂Much larger, i.e. T_2B>>T₂Thus 1/T in the formula_2BCan be ignored; when the magnetic field is very uniform (corresponding to G being very small), and T_EWhen sufficiently small, the third term on the right side of the equation is also negligible, so:

to obtain T₂The relationship with the aperture rc is:

in the formula: f_sCalled geometric form factor, for spherical pores, F_s＝3；

Namely:

r_c＝ρ₂×T₂×3，

for local area oil shale samples, ρ₂＝10μm/s。

The median pore radius is calculated according to the results shown in fig. 6-13, wherein the pore radius corresponding to the pore radius of 50% is the median nuclear magnetic pore radius when the pore radius is accumulated to 50% on the pore radius accumulation distribution diagram.

Fig. 6 and 10 are pore volume ratio and pore diameter distribution diagrams of samples of examples 1 and 2, wherein the abscissa represents pore diameter and the ordinate represents pore volume ratio.

Fig. 7 and 11 are graphs showing pore size distributions of the porosity components of the samples of examples 1 and 2, with the abscissa showing pore sizes and the ordinate showing porosity components.

Fig. 8 and 12 are bar graphs of pore size distribution of the samples of examples 1 and 2, with pore size on the abscissa and pore volume ratio on the ordinate.

Fig. 9 and 13 are cumulative distributions of pore diameters for the samples of examples 1 and 2, with the abscissa representing the pore diameter and the ordinate representing the cumulative pore volume ratio.

5. And outputting a result:

combining fig. 2 and 5 can obtain:

(1) sample 1 fresh sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007 to 4.553 ms; 2, the relaxation time of the peak is 5.354-91.159 ms;

sample 2 fresh sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007 to 6.295 ms; 2 peak relaxation time: 6.826-29.332 ms;

(2) sample 1 saturated water sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007 to 4.199 ms; 2, the relaxation time of the peak is 8.704-77.526 ms;

sample 2 saturated water sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007 to 6.295 ms; 2 peak relaxation time: 6.826-107.189 ms;

(3) sample 1 manganese saturation sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007 to 4.937 ms; 2 peak relaxation time: 13.049-47.686 ms;

sample 2 manganese saturation sample has 2 peaks, T₂Relaxation times are, 1 peak relaxation time: 0.007-8.026 ms; 2 peak relaxation time: 23.004-65.932 ms;

(4) after calibration is finished, the saturated manganese sample semaphore is used as an oil semaphore and is converted into an oil volume according to an oil calibration equation; subtracting the saturated manganese sample semaphore from the fresh sample semaphore to be used as a water semaphore, and converting the water semaphore into a water volume according to a water scaling equation; the volume of the oil and the volume of the water are the pore volume of the sample, the volume of the sample is measured by a density balance,

dividing the pore volume by the sample volume to obtain the sample porosity;

dividing the oil volume by the pore volume to obtain the oil saturation of the sample;

substituting data according to a formula in the SDR model to calculate the SDR permeability of the sample;

will T₂And (3) converting the relaxation time of the horizontal axis of the spectrum into the pore size, so as to obtain the pore size distribution and the median value of the pore radius of the core sample, as shown in fig. 6-13.

The final results are shown in table 4 below:

table 4 core sample test results

Numbering	Example 1	Example 2
			Fresh sample signal volume	4769.026	7704.751
Saturated water sample semaphore	6651.720	10473.497
			Semblance-like semaphore	2150.493	2336.826
Nuclear magnetic porosity%	4.92	7.71
			Oil saturation%	56.81	44.08
Original water saturation%	25.30	37.03
			The amount of escapement is%	17.89	18.89
SDR Permeability mD	0.76	6.63
			Median pore radius μm	0.013	0.015

Test example 2

The test example is a stability and accuracy test of the present application.

1. Stability of

The 4 samples are newly selected and are marked as samples A1, A1-1, A2 and A2-1, wherein the samples A1 and A1-1 are a group of parallel samples, the samples A2 and A2-1 are a group of parallel samples, the test method is carried out according to the test method in the example 1, the nuclear magnetic resonance spectrograms are respectively obtained and are shown in figures 14-17, and then the core physical properties are calculated according to the method of the test example, and the results are shown in the following table:

TABLE 5 table of the results of the comparative accuracy experiment

Sample numbering	A1	A1-1		A2	A2-1
						Fresh sample signal volume	5461.97486	4793.878465		2391.65248	5583.147865
Saturated water sample semaphore	7138.857754	6265.510457		3534.482254	7755.615673
						Manganese saturation-like signal quantity	1959.026828	1736.371812		1215.183197	2638.369213
Mass g	6.52	5.53		3.59	7.57
						Density g/cm3	2.46	2.44		2.43	2.38
Sample volume cm3	2.65	2.26		1.48	3.18
						Nuclear magnetic porosity%	7.95	8.49		7.42	7.58
Oil saturation%	43.83	44.18		52.13	51.54
						Original water saturation%	38.22	37.95		24.63	25.20
The amount of escapement is%	17.95	17.88		23.24	23.26
						SDR Permeability mD	1.25	1.19		0.91	0.96
Median pore radius um	0.015	0.015		0.013	0.013

As shown in the table above, the physical property data of the core obtained by each group of parallel samples, namely the nuclear magnetic porosity, the oil saturation, the original water saturation, the loss, the permeability and the median value of the pore radius are basically consistent, which shows that the test method of the application has better consistency and strong stability.

2. Accuracy of

Two (2) samples, designated as samples B1 and B2, were again selected and tested according to the test method of example 1 to obtain nmr spectra as shown in fig. 18 and 19, respectively, and then the core properties were calculated according to the method of the test example, and the oil saturations of samples B1 and B2 were tested using the laboratory method chloroform bitumen "a" oil saturation test, with the results shown in the following table:

TABLE 6 table of accuracy comparison experiment results

As can be seen from the above table, in the tests of samples B1 and B2, the test method used in the present application is consistent with the oil content test result of the chloroform bitumen "A" in the traditional laboratory, which indicates that the present application has higher accuracy.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.