CN116183458A - Shale oil effective porosity determination method - Google Patents
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- 239000003079 shale oil Substances 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 48
- 239000011148 porous material Substances 0.000 claims abstract description 102
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 67
- 238000002474 experimental method Methods 0.000 claims abstract description 39
- 238000001228 spectrum Methods 0.000 claims abstract description 38
- 239000003350 kerosene Substances 0.000 claims abstract description 27
- 238000005481 NMR spectroscopy Methods 0.000 claims abstract description 24
- 238000005303 weighing Methods 0.000 claims abstract description 15
- 238000004891 communication Methods 0.000 claims abstract description 12
- 238000011160 research Methods 0.000 claims abstract description 10
- 239000011435 rock Substances 0.000 claims abstract description 10
- 238000005119 centrifugation Methods 0.000 claims abstract description 7
- 238000002791 soaking Methods 0.000 claims abstract 2
- 238000002459 porosimetry Methods 0.000 claims 1
- 238000011161 development Methods 0.000 abstract description 9
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 14
- 229910052753 mercury Inorganic materials 0.000 description 14
- 238000002347 injection Methods 0.000 description 7
- 239000007924 injection Substances 0.000 description 7
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- 239000005416 organic matter Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 239000011800 void material Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 235000011850 desserts Nutrition 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000001225 nuclear magnetic resonance method Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
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- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/088—Investigating volume, surface area, size or distribution of pores; Porosimetry
- G01N15/0893—Investigating volume, surface area, size or distribution of pores; Porosimetry by measuring weight or volume of sorbed fluid, e.g. B.E.T. method
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Abstract
The invention provides a shale oil effective porosity determination method, which comprises the following steps: selecting shale rock samples of a research area, and weighing dry weight of a core; vacuumizing the shale sample block, and performing high-pressure saturated kerosene; weighing the sample in air and soaking in kerosene; calculating the volume and the porosity value of shale communication pores; performing nuclear magnetic resonance experiments on shale samples to obtain shale T2 spectrum and nuclear magnetic signal quantity in shale core saturation state; carrying out a centrifugal experiment and a nuclear magnetic resonance experiment on a shale sample to obtain a core T2 spectrum after centrifugation; comparing the T2 spectrum curves of the shale in a saturated state and a centrifugal state, and determining a movable lower limit of a pore; counting nuclear magnetic signal quantity which is more than or equal to the movable lower limit of the pore under the shale saturation state; and calculating the effective pore volume and the effective porosity according to the ratio of the nuclear magnetic signal quantity of the front and the rear times. The method can characterize the pores for occurrence and use, and accurately measure the shale oil pores which can contribute to shale oil development.
Description
Technical Field
The invention relates to the technical field of shale oil exploration and development, in particular to a shale oil effective porosity determination method.
Background
Shale is relatively compact sandstone, micro-nano scale pores are developed in a large quantity, organic pores and inorganic pores exist, not all the used pores can contribute in the shale oil development process, a part of the pores with small size are ineffective pores in the shale oil development process, and the rest of the pores are effective pores for shale development. The effective pore volume of the shale oil is accurately represented, the effective porosity of the shale oil is clarified, and the method has important significance for productivity prediction of the shale oil, optimization of development technology, selection of reservoir desserts and the like.
The Chinese patent application CN 109285137A discloses a method and a device for acquiring shale porosity, wherein a scanning electron microscope is utilized to scan a core sample to obtain a scanning electron microscope image of the core sample, the scanning electron microscope image is subjected to gray scale treatment, the image subjected to gray scale treatment is subjected to binary treatment according to a preset gray scale threshold interval of each component to obtain a binary image of each component, wherein each component comprises organic matter pores, organic matters, inorganic mineral pores and inorganic minerals, the organic matter porosity, the inorganic mineral porosity and the total porosity are calculated and obtained according to the pixel number of each component of the binary image of each component, and the contribution of the organic matter pores and the contribution of the inorganic mineral pores are calculated and obtained according to the organic matter porosity, the inorganic mineral porosity and the total porosity, so that the contribution of different types of shale pores can be acquired, and further an evaluation basis is provided for the follow-up accurate evaluation of oil and gas reserves. The method mainly comprises the steps of obtaining shale pictures through a scanning electron microscope, and identifying pores in the pictures, wherein the method cannot identify pores of a three-dimensional sample, and meanwhile, connectivity among the pores cannot be characterized.
The Chinese patent application CN 106483056B discloses a shale porosity measurement method and a shale porosity measurement device based on longitudinal wave velocity, and aims to solve the problems that a conventional rock porosity measurement method needs measurement media and the measurement media cannot fill all pores of shale; the device consists of a pressurizing system, an acoustic wave emission system, an acoustic wave acquisition system and a data processing system, wherein the pressurizing system of the device is controlled by a computer to realize automatic pressurization; after the pressure is set by the pressurizing system, the pressurizing pump can realize automatic pressurizing, the degree of automation is high, and the labor intensity of operators is reduced. The method and apparatus do not characterize the effective porosity of shale.
Chinese patent application CN 110849785A discloses a method for characterizing shale pore connectivity by multiple mercury intrusion experiments, comprising the steps of: s1, weighing a sample with a certain weight, and preprocessing the sample; s2, carrying out a first mercury injection experiment on the sample subjected to pretreatment in the step S1, and respectively obtaining first incremental mercury injection volumes corresponding to different pore diameters of the sample after the first mercury injection experiment is finished; s3, carrying out a second mercury injection experiment on the sample subjected to the first mercury injection experiment in the S2, and respectively obtaining second incremental mercury injection volumes corresponding to different pore diameters of the sample after the second mercury injection experiment is finished; s4, performing difference treatment on the first increment mercury inlet volume obtained in the S2 and the second increment mercury inlet volume obtained in the S3 according to the same pore diameter to obtain residual mercury quantity with the same pore diameter after two mercury pressing experiments, wherein the residual mercury quantity is used for representing pore connectivity of a sample. The method can obtain the communication pores of the shale sample, but cannot obtain the available effective pores.
Currently, tests on shale porosity mainly comprise helium pore method and fluid saturation method, tests on shale pore structure mainly comprise mercury compression method, nitrogen adsorption method and nuclear magnetic resonance method, the above methods can be used for characterizing the communicated pore volume or porosity in shale oil samples, but effective pore volume or porosity capable of contributing to shale development cannot be characterized, and meanwhile, the research on a system for shale oil effective porosity is less and the mature methods are less.
The prior art is greatly different from the method, the technical problem to be solved by the method is not solved, and a novel method for measuring the effective porosity of shale oil is invented.
Disclosure of Invention
The invention aims to provide an accurate shale oil effective porosity determination method for determining shale oil effective communication pores.
The aim of the invention can be achieved by the following technical measures: the method for measuring the effective porosity of the shale oil comprises the following steps:
step 1, selecting shale rock samples of a certain research area, and weighing dry weight of a core;
step 2, vacuumizing the shale sample block, and performing high-pressure saturated kerosene;
step 3, weighing the shale sample saturated under high pressure in air and immersing the shale sample in kerosene;
step 4, calculating the volume and the porosity value of the shale communication pores;
step 5, performing nuclear magnetic resonance experiments on shale samples to obtain shale T2 spectrum and nuclear magnetic signal quantity in shale core saturation state;
step 6, carrying out a centrifugal experiment and a nuclear magnetic resonance experiment on the shale sample to obtain a core T2 spectrum after centrifugation;
step 7, comparing T2 spectrum curves of shale in a saturated state and a centrifugal state, and determining a movable lower limit of a pore;
step 8, counting nuclear magnetic signal quantity which is more than or equal to the movable lower limit of the pore under the shale saturation state;
and 9, calculating the effective pore volume and the effective porosity according to the ratio of the nuclear magnetic signal quantity of the front nuclear magnetic resonance twice.
The aim of the invention can be achieved by the following technical measures:
in the step 1, selecting a shale rock sample of a certain research area, weighing a columnar shale core by using an electronic balance to obtain the dry sample weight m of the shale core g 。
In step 2, the shale sample is vacuumized, vacuumized for 2 hours at a vacuum degree of-0.1 MPa, and then high-pressure saturated kerosene is carried out on the shale sample, and the shale sample is saturated with the high-pressure saturated kerosene for 24 hours at 30 MPa.
In step 3, the shale sample saturated by high pressure is weighed in air to obtain the wet shale sample weight m s The saturated sample is completely soaked in kerosene and weighed, and the mass m is obtained l 。
In step 4, shale pore volume V is calculated p And porosity phi, the calculation formula is:
V p =(m s -m g )/ρ o
wherein: m is m g G, the weight of the shale core dry sample; v (V) p Shale pore volume, cm 3 ;ρ o Is kerosene density, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the Phi is shale porosity,%.
In step 5, nuclear magnetic resonance experiments are carried out on shale samples to obtain shale T2 spectrum and nuclear magnetic signal quantity A in shale core saturation state.
In step 6, a shale sample is subjected to a centrifugal experiment, the shale sample is centrifuged for 30 minutes at a centrifugal speed of 1 ten thousand rpm, and a nuclear magnetic resonance experiment is performed on the centrifuged shale sample to obtain a centrifuged core T2 spectrum.
In step 7, comparing the T2 spectrums in the saturated state and the centrifugal state, analyzing the minimum transverse relaxation time of the two times of T2 spectrum change, and determining the movable lower limit diameter R of shale pores d 。
In step 8, the nuclear magnetic signal quantity A of the pore movable lower limit or more in the saturated state is counted d 。
In step 9, the effective porosity phi is calculated according to the ratio of the nuclear magnetic signal quantity of the front and the back times e And effective pore volume V d 。
In step 9, the calculation formula for calculating the effective porosity and the effective pore volume is:
V d =φ e ×V p
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in a saturated state is dimensionless; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
According to the method for measuring the effective porosity of the shale oil, when the effective porosity of the shale oil is measured, fluid for shale is saturated under a high pressure state to obtain the effective communication pore volume of the shale, then a nuclear magnetic resonance experiment is carried out on a saturated shale sample to obtain a T2 spectrum, a centrifugal experiment is carried out on a shale core under 1 ten thousand revolutions per minute, the nuclear magnetic resonance experiment is carried out on the shale core after centrifugation, the shale nuclear magnetic T2 spectrum under the saturated state and the centrifugal state is compared, the lower limit of the shale pore volume is obtained, the pore volume larger than or equal to the lower limit of the shale pore volume is the effective pore volume of the shale oil, and the effective pore volume divided by the total pore volume is the effective porosity of the shale oil. The invention further subdivides the shale oil communication pores into effective communication pores and ineffective communication pores on the basis of the shale oil communication pores, and accurately determines the shale oil effective communication pores through experimental means such as high-pressure saturation, centrifugation, nuclear magnetic resonance and the like, calculates to obtain the shale oil effective porosity value, and overcomes the defects in the prior art.
Drawings
FIG. 1 is a flow chart of an embodiment of a shale oil effective porosity determination method of the present invention;
FIG. 2 is a graph of shale oil T2 in saturation in accordance with an embodiment of the present invention;
FIG. 3 is a graph of shale oil T2 in a centrifuged state in accordance with an embodiment of the present invention;
fig. 4 is a diagram of a determination of the movable lower limit of shale oil pores in an embodiment of the present invention.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular forms also are intended to include the plural forms unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, and/or combinations thereof.
As shown in fig. 1, fig. 1 is a flow chart of the shale oil effective porosity determination method of the present invention. The method for measuring the effective porosity of the shale oil comprises the following steps:
in step 1, selecting shale rock sample of a certain research area, and utilizing electronic daysWeighing the columnar shale core to obtain the dry sample weight m of the shale core g 。
In step 2, the shale sample is vacuumized, vacuumized for 2 hours at a vacuum degree of-0.1 MPa, and then high-pressure saturated kerosene is carried out on the shale sample, and the shale sample is saturated with the high-pressure saturated kerosene for 24 hours at 30 MPa.
In step 3, the shale sample saturated by high pressure is weighed in air to obtain the wet shale sample weight m s The saturated sample is completely soaked in kerosene and weighed, and the mass m is obtained l 。
In step 4, shale pore volume V is calculated p And porosity phi, the calculation formula is:
V p =(m s -m g )/ρ o
wherein: m is m g G, the weight of the shale core dry sample; v (V) p Shale pore volume, cm 3 ;ρ o Is kerosene density, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the Phi is shale porosity,%.
In step 5, nuclear magnetic resonance experiments are carried out on shale samples to obtain shale T2 spectrum and nuclear magnetic signal quantity A in shale core saturation state.
In step 6, a shale sample is subjected to a centrifugal experiment, the shale sample is centrifuged for 30 minutes at a centrifugal speed of 1 ten thousand rpm, and a nuclear magnetic resonance experiment is performed on the centrifuged shale sample to obtain a centrifuged core T2 spectrum.
In step 7, comparing the T2 spectrums in the saturated state and the centrifugal state, analyzing the minimum transverse relaxation time of the two times of T2 spectrum change, and determining the movable lower limit diameter R of shale pores d 。
In step 8, the nuclear magnetic signal quantity A of the pore movable lower limit or more in the saturated state is counted d 。
In step 9, the effective porosity phi is calculated according to the ratio of the nuclear magnetic signal quantity of the front and the back times e Calculation ofCalculation of effective pore volume V d 。
The effective porosity of shale is calculated, and the calculation formula is as follows:
V d =φ e ×V p
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in a saturated state is dimensionless; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
The following are several specific examples of the application of the present invention.
Example 1
In one embodiment 1 to which the present invention is applied, the shale oil effective porosity determination method comprises:
step 101, selecting a shale rock sample of a certain research area, and weighing a columnar shale core by using an electronic balance to obtain the dry sample weight m of the shale core g ,m g =27.309g。
Step 201, vacuuming the shale sample, vacuuming for 2 hours at a vacuum degree of-0.1 MPa, and then carrying out high-pressure saturated kerosene on the shale sample, and carrying out high-pressure saturated kerosene for 24 hours at 30 MPa.
Step 301, weighing a shale sample saturated under high pressure in air to obtain the wet shale sample weight m s = 27.322, the saturated sample is completely soaked in kerosene and weighed to obtain mass m l =17.577。
Step 401, calculating shale void volume V p And porosity phi, the calculation formula is:
V p =(m s -m g )/ρ o =(27.372-27.039)/0.8088=0.412cm 3
step 501, performing nuclear magnetic resonance experiments on a saturated shale sample to obtain a T2 spectrum of the shale in a core saturated state, see fig. 2, and obtaining shale nuclear magnetic signal quantity a= 1951.69 of the shale in the shale saturated state.
Step 601, performing a centrifugation experiment on a shale sample, centrifuging for 30min at 1 ten thousand rpm, and performing a nuclear magnetic resonance experiment on the centrifuged shale sample to obtain a T2 spectrum in a core centrifugation state, as shown in FIG. 3.
Step 701, comparing T2 spectrums in a saturated state and a centrifugal state, analyzing the minimum transverse relaxation time of the two T2 spectrums, and determining the movable lower limit diameter R of shale pores d =27.83 nm, see fig. 4.
Step 801, counting nuclear magnetic signal quantity Ad= 704.94 of which the diameter is larger than or equal to the movable lower limit diameter of the pore in the saturated state according to a T2 spectrum of the shale core in the saturated state.
Step 901, calculating effective porosity phi according to the ratio of nuclear magnetic signal quantity of front and back times e Calculating the effective pore volume V d 。
The effective porosity of shale is calculated, and the calculation formula is as follows:
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in a saturated state is dimensionless; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
The shale oil of an embodiment of the present invention has an effective porosity size of 1.23%.
Example 2:
in one embodiment 2 to which the present invention is applied, the shale oil effective porosity determination method comprises:
step 101, selecting a shale rock sample of a certain research area, and weighing a columnar shale core by using an electronic balance to obtain the dry sample weight m of the shale core g ,m g =32.083g。
Step 201, vacuuming the shale sample, vacuuming for 2 hours at a vacuum degree of-0.1 MPa, and then carrying out high-pressure saturated kerosene on the shale sample, and carrying out high-pressure saturated kerosene for 24 hours at 30 MPa.
Step 301, weighing a shale sample saturated under high pressure in air to obtain the wet shale sample weight m s = 32.913, the saturated sample is completely soaked in kerosene and weighed to obtain mass m l =22.895。
Step 401, calculating shale void volume V p And porosity phi, the calculation formula is:
V p =(m s -m g )/ρ o =(32.913-32.083)/0.8088=1.027cm 3
step 501, performing nuclear magnetic resonance experiments on a saturated shale sample to obtain a T2 spectrum in a core saturation state, and obtaining shale nuclear magnetic signal quantity A= 1748.22 in the shale saturation state.
And 601, performing a centrifugal experiment on the shale sample, centrifuging for 30min at 1 ten thousand rpm, and performing a nuclear magnetic resonance experiment on the centrifugal shale sample to obtain a T2 spectrum in a core centrifugal state.
Step 701, comparing T2 spectrums in a saturated state and a centrifugal state, analyzing the minimum transverse relaxation time of the two T2 spectrums, and determining the movable lower limit diameter R of shale pores d =21.54nm。
Step 801, counting nuclear magnetic signal quantity Ad= 1496.48 of which the diameter is larger than or equal to the movable lower limit diameter of the pore in the saturated state according to a T2 spectrum of the shale core in the saturated state.
Step 901, calculating effective porosity phi according to the ratio of nuclear magnetic signal quantity of front and back times e Calculate the effective pore volume V d 。
The effective porosity of shale is calculated, and the calculation formula is as follows:
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in a saturated state is dimensionless; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
The shale oil of an embodiment of the present invention has an effective porosity size of 7.10%.
Example 3:
in one embodiment 3 of the present invention, the shale oil effective porosity determination method comprises:
step 101, selecting a shale rock sample of a certain research area, and weighing a columnar shale core by using an electronic balance to obtain the dry sample weight m of the shale core g ,m g =21.2g。
Step 201, vacuuming the shale sample, vacuuming for 2 hours at a vacuum degree of-0.1 MPa, and then carrying out high-pressure saturated kerosene on the shale sample, and carrying out high-pressure saturated kerosene for 24 hours at 30 MPa.
Step 301, weighing a shale sample saturated under high pressure in air to obtain the wet shale sample weight m s =21.72, the saturated sample is fully immersed in kerosene and weighed to obtain mass m l =13.386。
Step 401, calculating shale void volume V p And porosity phi, the calculation formula is:
V p =(m s -m g )/ρ o =(21.72-21.2)/0.8088=0.642cm 3
step 501, performing nuclear magnetic resonance experiments on a saturated shale sample to obtain a T2 spectrum in a core saturation state, and obtaining shale nuclear magnetic signal quantity A= 1086.30 in the shale saturation state.
And 601, performing a centrifugal experiment on the shale sample, centrifuging for 30min at 1 ten thousand rpm, and performing a nuclear magnetic resonance experiment on the centrifugal shale sample to obtain a T2 spectrum in a core centrifugal state.
Step 701, comparing T2 spectrums in a saturated state and a centrifugal state, analyzing the minimum transverse relaxation time of the two T2 spectrums, and determining the movable lower limit diameter R of shale pores d =35.94nm。
Step 801, counting nuclear magnetic signal quantity Ad= 676.15 of which the diameter is larger than or equal to the movable lower limit diameter of the pore in the saturated state according to a T2 spectrum of the shale core in the saturated state.
Step 901, calculating effective porosity phi according to the ratio of nuclear magnetic signal quantity of front and back times e Calculate the effective pore volume V d 。
The effective porosity of shale is calculated, and the calculation formula is as follows:
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in saturation state without causeSecondary times; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
The shale oil of an embodiment of the present invention has an effective porosity size of 3.86%.
According to the method, when the effective porosity of shale is measured, shale communication pores are divided into effective pores and ineffective pores, the lower limit of the pores which can be used by the high-pressure saturation, centrifugal experiment and nuclear magnetic resonance experiment technology is determined, the pores which can be used by the shale are characterized, the shale oil pores which can contribute to shale oil development are accurately measured, and the method provides effective technical support for the preparation of the prediction and development scheme of the lamellar shale oil field productivity.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but although the present invention has been described in detail with reference to the foregoing embodiment, it will be apparent to those skilled in the art that modifications may be made to the technical solution described in the foregoing embodiment, or equivalents may be substituted for some of the technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Other than the technical features described in the specification, all are known to those skilled in the art.
Claims (11)
1. The method for measuring the effective porosity of the shale oil is characterized by comprising the following steps of:
step 1, selecting shale rock samples of a certain research area, and weighing dry weight of a core;
step 2, vacuumizing the shale sample block, and performing high-pressure saturated kerosene;
step 3, weighing the shale sample saturated under high pressure in air and immersing the shale sample in kerosene;
step 4, calculating the volume and the porosity value of the shale communication pores;
step 5, performing nuclear magnetic resonance experiments on shale samples to obtain shale T2 spectrum and nuclear magnetic signal quantity in shale core saturation state;
step 6, carrying out a centrifugal experiment and a nuclear magnetic resonance experiment on the shale sample to obtain a core T2 spectrum after centrifugation;
step 7, comparing T2 spectrum curves of shale in a saturated state and a centrifugal state, and determining a movable lower limit of a pore;
step 8, counting nuclear magnetic signal quantity which is more than or equal to the movable lower limit of the pore under the shale saturation state;
and 9, calculating the effective pore volume and the effective porosity according to the ratio of the nuclear magnetic signal quantity of the front nuclear magnetic resonance twice.
2. The method for measuring effective porosity of shale oil according to claim 1, wherein in step 1, a shale rock sample of a certain research area is selected, and a columnar shale core is weighed by an electronic balance to obtain dry sample weight m of the shale core g 。
3. The method for measuring effective porosity of shale oil according to claim 1, wherein in the step 2, the shale sample is vacuumized, vacuumized for 2 hours at a vacuum degree of-0.1 MPa, and then subjected to high-pressure saturated kerosene, and saturated kerosene is at a high pressure of 30MPa for 24 hours.
4. The method for determining effective porosity of shale oil according to claim 1, wherein in step 3, the shale sample saturated under high pressure is weighed in air to obtain shale wet sample weight m s Fully soaking the shale sample saturated under high pressure in kerosene for weighing to obtain the mass m l 。
5. The shale oil effective porosimetry method according to claim 4, wherein in step 4, shale pore volume V is calculated p And porosity phi, which is calculated byThe formula is:
V p =(m s -m g )/ρ o
wherein: m is m g G, the weight of the shale core dry sample; v (V) p Shale pore volume, cm 3 ;ρ o Is kerosene density, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the Phi is shale porosity,%.
6. The method for determining effective porosity of shale oil according to claim 1, wherein in step 5, nuclear magnetic resonance experiments are performed on shale samples to obtain a shale T2 spectrum and a nuclear magnetic signal quantity a in a shale core saturation state.
7. The method for measuring effective porosity of shale oil according to claim 1, wherein in step 6, a centrifugal experiment is performed on a shale sample, the shale sample is centrifuged for 30 minutes at a centrifugal speed of 1 ten thousand rpm, and a nuclear magnetic resonance experiment is performed on the centrifuged shale sample to obtain a centrifuged core T2 spectrum.
8. The method for determining effective porosity of shale oil according to claim 1, wherein in step 7, the T2 spectra of the saturated state and the centrifugal state are compared, the minimum transverse relaxation time of the two T2 spectra is analyzed, and the movable lower limit diameter R of shale pores is determined d 。
9. The method for measuring effective porosity of shale oil according to claim 1, wherein in step 8, the nuclear magnetic signal quantity a of the pore movable lower limit or more in the statistical saturation state is calculated d 。
10. The method for determining effective porosity of shale oil according to claim 1, wherein in step 9, the ratio of nuclear magnetic signal values is calculated according to the two times of nuclear magnetic signal valuesCalculate the effective porosity phi e And effective pore volume V d 。
11. The method of determining effective porosity of shale oil according to claim 10, wherein in step 9, the calculation formula for calculating the effective porosity and the effective pore volume is:
V d =φ e ×V p
in phi e Effective porosity,%; a, nuclear magnetic signal quantity in a saturated state is dimensionless; a is that d The nuclear magnetic signal quantity is larger than or equal to the movable lower limit diameter in the saturated state, and the dimensionless is realized; phi is shale porosity,%; v (V) d For effective pore volume, cm 3 ;V p Shale pore volume, cm 3 。
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CN117129509B (en) * | 2023-10-27 | 2023-12-26 | 东北石油大学三亚海洋油气研究院 | Method for calculating shale fracture nuclear magnetic resonance logging T2 cut-off value based on KI-CT |
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