JP2007132795A - Vitrinite reflectance measuring method, and vitrinite reflectance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vitrinite reflectance measuring method and a device capable of measuring a reflectance surely without destroying a coal-including rock sample, concerning a vitrinite particle included in the coal-including rock sample, even if it is a fine particle. <P>SOLUTION: In this vitrinite reflectance measuring method, the coal-including rock sample is polished to form an observation surface, and a square part carrying particle having a square shape partitioned by two projecting sides on the inside, exposed on the observation surface observed with a magnification of 200-1,000 times is discriminated as the vitrinite particle, and the reflectance on the surface domain is measured. In the vitrinite reflectance measuring device, which is used for the measuring method and equipped with a photodiode as a photometric means, the diameter of vertical illumination light can be adjusted below 75 μm, and the diameter of a photometric area can be adjusted below 10 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for measuring the reflectance of vitrinite contained in a coal-containing rock sample and a measuring apparatus used in the method.

  For example, in order to estimate the amount of uplift in the formation or the maturity of fossil fuel in the formation, the geological structure has been used in the past by using physicochemical changes in rocks such as sedimentary rocks. The temperature environment received (hereinafter, also simply referred to as “old-earth temperature environment”) and its change are estimated. And when the temperature range related to the paleothermal environment to be estimated is, for example, about several tens of degrees Celsius to 300 ° C, the paleothermal environment is measured by measuring the reflectance of vitrinite contained in the geological body, It is widely known that it can be estimated effectively.

Vitrinite is a major component of the organic matter that makes up coal, and is therefore a group of microstructure components present in almost all coal. Vitrinite is mainly derived from the woody part of the plant, but since it is in a gelled state due to its thermoplasticity, for example, the source plant tissues such as cell cells and conduits are decomposed into a homogeneous state. In the observation of vitrinite, it looks grayish white under reflected light, and as the coalization progresses, the reflectance becomes higher and the color becomes lighter.
This vitrinite reflectance is widely used in the coal and coke industry as an important indicator of coal quality (see, for example, Patent Document 1), and a method for measuring such a vitrinite reflectance is in accordance with JIS M 8816: 1992. It has been standardized.

In JIS M 8816: 1992, an appropriate amount of a coal-containing rock sample is pulverized as a sample to be measured, and fine particles having a particle size of 75 μm or less are separated from the pulverized material by, for example, a heavy liquid separation method. Larger coal particles are obtained, briquettes are created by embedding the coal particles in a light-transmitting resin such as acrylic resin, and the surface to be observed is formed by polishing the briquettes and equipped with an epi-illumination mechanism. The reflectance of the surface region related to vitrinite exposed on the surface to be observed is measured using the measuring device.
Here, “particle size” for a certain particle means the diameter of the smallest circle that can contain the particle.

  However, coal is made of maceral which is various constituents such as vitrinite and inertite, and the coal particles separated from the coal-containing rock sample contain a lot of other various particles besides vitrinite. For this reason, when measuring the reflectance of vitrinite particles, it is necessary to determine in advance the vitrinite particles in the coal particles.

  As described above, in vitrinite, source plant tissues such as cell cells and conduits are lost and become homogeneous, but such source plant tissues remain in other fine tissue components or component groups. Therefore, in the conventional measurement of vitrinite reflectance, using the difference in the presence of the source plant tissue, a particle in which the source plant tissue is not observed is found by observation with a microscope, and the work of discriminating it as vitrinite particles is performed. Has been done. And the reflectance measurement is performed about the vitrinite particle discriminated or recognized by this discrimination | determination work.

  However, in the conventional method, for fine coal particles having a particle size of 75 μm or less, the size of the fine coal particles is smaller than that of the source plant tissue, so that it is practically impossible to visually recognize the source plant composition. Because it is possible, it is not possible to distinguish even when a certain fine coal particle is a vitrinite particle. This means that, in the end, the vitrinite reflectance measurement cannot be actually performed for the fine coal particles having a particle size of 75 μm or less contained in the coal-containing rock sample. For such a coal-containing rock sample, There is a problem that it is impossible to obtain information for estimating the paleothermal environment for the geological body from which it originates.

Further, in the conventional measurement method, it is necessary to pulverize the coal-containing rock sample, but since the coal-containing rock sample is destroyed by this pulverization, the state of production of the coal-containing rock sample is lost. It is not possible to obtain environmental information relating to the state of production of vitrinite particles that have been subjected to reflectance measurement.
In addition, since the method for preparing the briquette as an observation sample has a step of pulverizing the coal-containing rock sample and selecting particles having a relatively large particle size, the reflectance value obtained is the same for the entire coal-containing rock sample. Therefore, there is a problem that the geological body from which the coal-containing rock sample is derived cannot be subjected to mapping of temperature distributions related to different paleo-temperature environments on a minute scale of, for example, a millimeter unit. is there.

  On the other hand, when a coal-containing rock sample is used as it is as a sample corresponding to a briquette without being crushed, in practice, a highly reflective substance other than vitrinite, such as pyrite, has a considerably high density on the observed surface of the sample. Often exposed. When the reflectance measurement for such a sample is performed by a conventional epi-illumination type reflectance measurement apparatus, it is difficult to accurately measure the reflectivity of minute vitrinite particles because the diameter of the epi-illumination light is large. There is a problem that. This is because even if the photometric area is reduced, the reflected light from the highly reflective substance acts as background light having a large light intensity with respect to the measured reflected light by vitrinite. This is because the reflectance cannot be measured accurately.

Japanese Patent Laid-Open No. 7-253398

  The present invention has been made on the basis of the above circumstances. The purpose of the present invention is to obtain a vitrinite particle contained in a coal-containing rock sample even when the coal-containing rock sample is a fine particle. It is an object of the present invention to provide a vitrinite reflectance measuring method and apparatus capable of reliably measuring the reflectance without breaking.

The vitrinite reflectance measuring method of the present invention is a method for measuring the reflectance of vitrinite contained in a coal-containing rock sample,
Polishing a coal-containing rock sample to form an observation surface,
Observing the surface to be observed at a magnification of 200 to 1000 times, distinguishing the corner-containing particles having an angular shape defined by two inwardly convex sides exposed on the surface to be observed as vitrinite particles,
The reflectance in the surface area of the discriminated vitrinite particle is measured.
In this method, the corner-containing particles may have a particle size of 75 μm or less.

The vitrinite reflectance measuring device of the present invention is a measuring device used in the above-described vitrinite reflectance measuring method,
A photodiode is provided as a photometric means,
The diameter of the incident light can be 75 μm or less, and the diameter of the photometric area can be 10 μm or less.

  According to the vitrinite reflectance measuring method of the present invention, in the coal particles contained in the coal-containing rock sample, most of the vitrinite particles are coal because the vitrinite as a measurement target is a substance having high thermoplasticity. In the flat surface formed by polishing the contained rock sample, it has a unique shape characteristic that can be referred to as “square shape”, but the maceral constituent particles such as inertite other than vitrinite are composed of Paying attention to the fact that the material has low thermoplasticity and does not have such an angular shape, the corner-containing particles are discriminated as vitrinite particles depending on the presence or absence of the angular shape, and the discriminated vitrinite particles Since the reflectance of the surface is measured, even for fine vitrinite particles having a particle size of 75 μm or less, for example. It is possible to reliably determine when is Torinitto particles, it is possible to reliably perform the vitrinite reflectance measurements of interest.

  Further, according to the vitrinite reflectance measurement method of the present invention, it is only necessary to polish the rock sample to form the surface to be observed. Therefore, the rock sample contained in the vitrinite particles to be subjected to reflectance measurement is crushed or destroyed. Is essentially unnecessary, and therefore the state of occurrence of the rock sample containing the vitrinite particles to be subjected to reflectance measurement is preserved as it is, so that the desired reflectance measurement can be performed non-destructively, In addition to the basic information (main information) obtained by measuring the reflectance of the vitrinite particles, environmental information that reinforces and complements the information can be easily acquired as incidental information, thereby measuring the reflectance of the vitrinite particles. The significance of the basic information obtained by this can be drastically increased.

Hereinafter, the vitrinite reflectance measuring method of the present invention will be described in detail.
FIG. 1 is an explanatory view schematically showing a typical example of an observation surface formed on a coal-containing rock sample, and FIG. 2 is an enlarged explanatory view for explaining a square shape in vitrinite particles.

  In the vitrinite reflectance measuring method of the present invention, a flat polished surface is formed by polishing a coal-containing rock sample, and this polished surface is used as a surface to be observed under a condition of 200 to 1000 times magnification with a microscope. A coal particle having at least one shape (this is referred to as a “corner shape”) in which a corner portion defined by two inwardly convex sides is formed in the contour on the observed surface. Is identified as “vitrinite particles”, and the reflectance of the vitrinite particles determined in this determination work is measured by the surface area exposed on the surface to be observed.

  Here, the “observed surface” is a flat surface including a surface on which the measurement of vitrinite reflectance is actually performed, and this observed surface is, for example, the outer surface of a coal-containing rock sample that is a measured sample. It can be formed by polishing so that a flat surface having an area of a prescribed size is formed. Or it can also form by cut | disconnecting a coal containing rock sample in arbitrary places, and grind | polishing the cut surface by this.

In the vitrinite reflectance measuring method of the present invention, sedimentary rock is usually used as a coal-containing rock sample.
As shown in FIG. 1, this sedimentary rock is structurally composed of vitrinite particles 10 and other non-target coal particles 11 which are maceral constituent particles such as inertinite and rock composition particles 12 such as quartz particles. Are formed in close contact with each other in three dimensions. In normal cases, the composition particles other than the vitrinite particles 10, that is, the non-target coal particles 11 and the rock composition particles 12, are selectively removed in the transport process before the deposition of the microprojections originally present in the particles. As a result of further wear, it has a shape with a smoothly curved contour as a whole, and as a result, voids defined by a plurality of curves between adjacent particles (hereinafter, “ It is referred to as “inter-particle gap”.) 13 is formed.

  Thus, the vitrinite particles 10 have higher thermoplasticity than the non-target coal particles 11 and the rock composition particles 12 which are other composition particles, and therefore are macroscopic in time and temperature. In the carbonization process after deposition, particles are formed by surrounding particles adjacent to the vitrinite particles as a result of being meltable or deformable due to its thermoplasticity due to its thermoplasticity. It flows so as to fill the interstitial space 13, and its contour shape is transformed into that according to the interparticle space 13, and then re-solidifies to have a shape corresponding to the shape of the interstices. .

  On the other hand, since the non-target coal particles 11 and the rock composition particles 12 have lower thermoplasticity than vitrinite, the shape of the coal particles 11 and the rock composition particles 12 do not change like vitrinite particles, and eventually have a curved outer surface. It exists as possessing a shape.

  Specifically, by way of a typical example, as shown in an enlarged view in FIG. 2, for example, two non-target coal particles 11 and / or rock composition particles 12 (in FIG. 2, two rock composition particles 12 In the case where the interparticle voids 13 are formed by contact with each other, the interparticle voids 13 are formed in such a manner that the rock composition particles 12 having a curved outer surface are located at one point or one point each other. Therefore, the interparticle voids 13 are usually in a state in which unique angular voids 13a having apexes at the contact points of the void-forming particles are formed in the interparticle voids 13. ing.

Since the vitrinite composition material has a shape according to such interparticle voids 13, the vitrinite particles 10 have a corner-holding shape in which a corner shape is formed in the corner voids 13 a of the interparticle voids 13. It becomes the corner | angular part holding | maintenance particle | grains which have.
That is, the vitrinite particles 10 are interparticle voids 13 that are partitioned by two outwardly convex curves L1 and L2 due to the contours of the outer surfaces of the two rock composition particles 12 and 12 that contact each other on the outer peripheral surface. As a result of having an outer shape that conforms to the inner shape of the interparticle void 13 so as to be filled, a corner-holding shape having a corner portion 20 showing at least one corner shape by the corner-shaped void portion 13a is formed. State, in other words, the corner portion 20 that protrudes outward, and extends in accordance with each of the outwardly convex curves L1 and L2 that define the interparticle voids 13, and extends inwardly on the two sides 21 and 21 It becomes the corner | angular part holding | maintenance particle | grains which have the square shape divided by.

  As is apparent from the above description, the vitrinite particles 10 are usually formed in a square shape which is a shape according to the above-mentioned square void portion 13a in the interparticle voids 13. In the measurement of vitrinite reflectance, vitrinite particles 10 are distinguished from other non-target particle particles based on the presence or absence of a square shape in a large number of coal particles exposed on the observed surface 14 when measuring vitrinite reflectance. can do.

  Therefore, in the vitrinite reflectance measuring method of the present invention, the corner-containing particles having the above-described characteristics are obtained at a magnification of 200 to 1000 times, preferably 400 to 1000 times, specifically, for example, 600 times. The corner-containing particles are determined to be vitrinite particles by discovery, and the surface reflectance of the vitrinite particles determined by this determination operation is measured. In this way, the reflectance measurement of the surface of the vitrinite particles contained in the rock sample is selectively performed.

  In the above, when the magnification in the observation with a microscope is higher than 1000 times, corners formed due to the thermoplasticity of vitrinite particles and, for example, inertite that was not removed because it was very small in the transport process before deposition In some cases, it is difficult to reliably discriminate corners existing in non-target coal particles such as particles, and the reliability of the identification probability is low. On the other hand, when the magnification is lower than 200 times, it may be very difficult to identify the square shape of the vitrinite particles for a fine rock sample particle of 75 μm or less, for example.

As described above, according to the vitrinite particle reflectance measurement method of the present invention, even for fine coal particles having a particle size of, for example, 75 μm or less, the coal particles are vitrinite particles with high efficiency and reliability. It can be easily discriminated visually from the shape.
As a result, for example, vitrinite particles in coal-containing rock samples that were 75 μm or less and could not be measured by conventional methods and could not be determined as vitrinite particles were also vitrinite particles. Can be identified with sufficient reliability, and the reflectance measurement of the surface can be performed.

Moreover, in the present invention, it is not necessary to destroy the coal-containing rock sample that is essentially the sample to be measured, not only in the reflectance measurement operation but also in the discrimination operation.
Therefore, in addition to the basic information obtained by measuring the reflectivity of vitrinite particles, it is easy to obtain incidental information on the environment or situation that reinforces and complements the basic information. Therefore, the basic information obtained by measuring the reflectivity of vitrinite particles is obtained. The significance of information can be dramatically increased.
As a result, for example, the estimation of the paleothermal environment can be easily performed for a larger number of geological bodies, and the position information of individual vitrinite particles and the information on the reflectivity status of each of them are very small scales. Therefore, it is possible to detect, for example, frictional heating along a fault in the past and local thermal anomalies due to hydrothermal fluid, and to map these finely.

FIG. 3 is an explanatory side sectional view schematically showing an example of the configuration of an apparatus suitably used for carrying out the above vitrinite reflectance measurement method.
In this example, the reflectance measuring apparatus 30 basically includes a table 32 having a horizontal placement surface for placing the sample 31 to be measured, and a light source lamp 33 for supplying incident light to the sample 31 to be measured. And photometric means 34 made of a silicon photodiode for measuring the reflected light reflected from the sample 31 to be measured.

  In the reflectance measuring device 30, on the optical path from the light source lamp 33, a lens 35 for focusing the light from the light source lamp 33 and an incident light area on the sample 31 to be measured by the light from the lens 35. A diaphragm mechanism 36 is provided for defining the light, and light having a wavelength of 545 nm is transmitted as high as 50 to 90%, for example, on the optical path of the reflected light from the sample 31 to be measured and before the photometric means 34. A band pass filter 37 that transmits at a rate is provided. In the illustrated example, reference numeral 38 denotes an eyepiece unit, and the alternate long and short dash line indicates an optical path.

  Here, as the light source lamp 33, for example, a halogen incandescent lamp or a xenon discharge lamp with power consumption of 75 W or more can be preferably used.

In such a reflectance measuring apparatus 30, in order to carry out the method in a state where the features of the above-mentioned vitrinite reflectance measuring method are fully utilized, the diaphragm mechanism 36 causes the surface to be observed relating to the sample 31 to be measured to be observed. The diameter of the incident light is preferably 75 μm or less, and in the case of normal light that is not laser light, the diameter is preferably about 30 μm, for example.
On the other hand, the photometric area that is a part of the incident light area is preferably, for example, 10 μm or less in diameter. When the diameter of the incident light is 10 μm or less, the diameter is preferably 1 to 2 μm.

  In the vitrinite reflectance measuring apparatus of the present invention, the incident light area is set in such a range, so that even when a coal-containing rock sample polished as the sample 31 is used, On the observation surface, it is possible to reduce the possibility that a highly reflective substance such as pyrite is present in the incident light area, and to reduce the intensity of reflected light other than that caused by vitrinite particles in the incident light area. Therefore, the reflected light related to the vitrinite particles can be measured with high accuracy. That is, there is very little possibility that a highly reflective substance other than the vitrinite particle to be measured exists in the photometry area. As a result, the vitrinite particles to be measured are small particles having a small particle size. Even so, the reflectance of the surface can be measured with high accuracy.

  In the vitrinite reflectance measuring method using the reflectance measuring apparatus 30 described above, first, a coal-containing rock sample is collected from a geological object intended to estimate the paleothermal environment, and the coal-containing rock sample is polished. The sample to be measured 31 is formed by forming the surface to be observed by cutting the surface by cutting at an arbitrary position or by polishing the cut surface, and placing the sample to be measured 31 on the table 32.

  Then, the observation surface of the sample 31 to be measured is observed at a magnification of 200 to 1000 times through the eyepiece unit 38, and the corner-containing particles having a horn shape are discriminated as vitrinite particles to be a measurement object. Vitrinite particles are selected, light from the light source lamp 33 is incident on the selected vitrinite particles, and the reflected light is measured by the photometric means. An electric signal obtained as a result of the photometric means 34 receiving the reflected light is amplified by an amplifier (not shown) and processed in an appropriate electronic computer (not shown).

According to the vitrinite reflectance measuring apparatus described above, even when using a coal-containing rock sample itself having an observation surface as a measurement sample, high reflectivity other than vitrinite particles exposed on the observation surface. Since reflection by the substance is reduced, the target reflectance measurement can be reliably performed on the vitrinite particles.
In addition, since inexpensive and easy-to-handle photodiodes are used as photometric means, the entire measuring device is inexpensive and easy to handle, and even when the diameter of the photometric area is set to be extremely small, Since the reduction of the S / N ratio is suppressed in the obtained electrical signal, the reflectance of vitrinite particles can be measured with high accuracy.

  As mentioned above, although the vitrinite reflectance measuring method and the vitrinite reflectance measuring apparatus of the present invention have been described with specific examples, the present invention is not limited to these, and various modifications can be added.

It is explanatory drawing which shows typically the typical example of the to-be-observed surface formed in the coal containing rock sample. It is an enlarged explanatory view for explaining a square shape in vitrinite particles. It is sectional drawing for description which shows schematically the structure of the vitrinite reflectance measuring apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vitrinite particle | grains 11 Excluded coal particle 12 Rock composition particle 13 Interstitial void 13a Square void portion L1, L2 Curve 14 Surface to be observed 20 Corner portion 21 Side 30 Reflectance measuring device 31 Sample to be measured 32 Table 33 Light source lamp 34 Photometry Means 35 Lens 36 Aperture mechanism 37 Band pass filter 38 Eyepiece unit

Claims (3)

A method for measuring the reflectance of vitrinite contained in a coal-containing rock sample,
Polishing a coal-containing rock sample to form an observation surface,
Observing the surface to be observed at a magnification of 200 to 1000 times, distinguishing the corner-containing particles having an angular shape defined by two inwardly convex sides exposed on the surface to be observed as vitrinite particles,
A method of measuring vitrinite reflectivity, comprising measuring the reflectivity in the surface region of the discriminated vitrinite particles.   The vitrinite reflectance measuring method according to claim 1, wherein the particle size of the corner-holding particles is 75 μm or less. A measuring device used in the vitrinite reflectance measuring method according to claim 1 or 2,
A photodiode is provided as a photometric means,
A vitrinite reflectance measuring apparatus characterized in that the diameter of incident light can be 75 μm or less and the diameter of a photometric area can be 10 μm or less.

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