JP4564306B2 - Tracer test apparatus and tracer test method - Google Patents

Description

The present invention relates to a tracer test apparatus and a tracer test method for grasping a mass transfer characteristic of a sample.

  As a test method for grasping the mass transfer characteristics (for example, the mass transfer opening width and the dispersion length in the crack) in rocks with a single crack, a tracer solution containing the tracer material is infiltrated from the water injection surface of the rock sample. There is a tracer test to measure the mass transfer characteristics of a rock sample by measuring the change over time (breakthrough curve) of the tracer concentration in the tracer solution flowing out from the drainage surface of the rock sample, and comparing this measurement result with the theoretical curve (For example, refer nonpatent literature 1).

  As shown in FIG. 2, the tracer test apparatus used for the tracer test is capable of storing a tracer solution containing a tracer substance and supplying the tracer solution to a water injection surface 51 of a rock sample 50 having a single crack 53. There is a tracer test apparatus 1 ′ that includes a possible supply tank 60 and a measurement tank 70 that can collect and store the tracer solution that has flowed out of the drainage surface 52 of the rock sample 50. In this tracer test apparatus 1 ′, concentration measuring means (not shown) capable of measuring the tracer concentration is provided in the measuring tank 70, and the measuring tank 70 and the drainage surface 52 of the rock sample 50 are connected via the drainage pipe 71. Connected.

In the tracer test using the tracer test apparatus 1 ′, first, the tracer solution is supplied from the supply tank 60 to the water injection surface 51 of the rock sample 50 and infiltrated. Then, the tracer solution that has passed through the rock sample 50 and has flowed out of the drainage surface 52 is stored in the measurement tank 70 through the drainage pipe 71, and the change with time of the tracer concentration is measured by the concentration measuring means provided in the measurement tank 70.
Ivars Neretniks, Tryggve Eriksen, and Paivi Tahtinen, “Tracer migration in a single fissure in granite: some test results and their interpretation (Tracer Movementa in Single Fissure in Granitic Rock: Some Experimental Results and Their Interpretation), Water Resources Research, (USA), American Geophysical Union, August 1982, Vol. 18, No. 4, p. . 849-858

  However, in the tracer test apparatus 1 ′, the tracer solution flowing out from the rock sample 50 moves in the drain pipe 71 and is stored in the measurement tank 70, so that the dispersion phenomenon of the tracer solution occurs in the drain pipe 71. There is a possibility that the reliability of the measurement result is remarkably impaired.

  Further, in a tracer test for a sample having a relatively high porosity, a tracer solution is supplied at a low flow rate in consideration of a delay effect due to a diffusion phenomenon (matrix diffusion phenomenon) from a crack to a substrate portion. In such a case, in the tracer test apparatus 1 ′, a tracer solution flushing mechanism (not shown) is provided on the drainage surface 52 side of the rock sample 50 in order to shorten the residence time of the tracer solution in the drainage pipe 71. Although provided, there is a problem that the measurement error increases due to dilution of the tracer solution by flushing.

Therefore, in the present invention, the above-described problems can be solved, measurement can be performed without considering the dispersion phenomenon of the tracer solution between the drainage surface of the sample and the measurement position, and a flushing mechanism for the tracer solution is provided. It is an object of the present invention to provide a tracer test apparatus and a tracer test method capable of obtaining an accurate measurement result by supplying a tracer solution to a sample at a low flow rate.

In order to solve the above-mentioned problem, the invention according to claim 1 is a tracer test apparatus, and is capable of storing a tracer solution containing a tracer substance and supplying means for supplying the tracer solution to a water injection surface of a sample. And a measuring tank disposed in contact with the drainage surface of the sample , wherein the measurement tank has a discharge opening facing the drainage surface of the sample, and the tracer solution supplied from the supply means to the water injection surface of the sample However, it is characterized by being configured to pass through the sample and directly flow into the measuring tank from the drainage surface.
The invention according to claim 5 is a tracer test method using the above-described tracer test apparatus, the step of filling the inside of the measurement tank with deionized deaerated water, and the tracer from the supply means to the water injection surface of the sample. It is characterized by comprising a step of supplying a solution, a step of allowing the tracer solution that has passed through the sample to directly flow into the measurement tank from the drainage surface, and a step of measuring the tracer concentration in the measurement tank.

  Here, the structure of a sample is not limited, The sample of various compositions can be made into a test object, for example, the rock which has a single crack can be used.

Thus, in this onset bright, measuring tank for storing the tracer solution that has passed through the sample is arranged in contact with the sample, the tracer solution flowing out from the sample would directly flow into the measuring tank. Thereby, when measuring the tracer concentration of the tracer solution in the measurement tank, it is not necessary to consider the dispersion phenomenon of the tracer solution between the sample and the measurement position, and thus the reliability of the measurement result can be improved.

  In addition, since the tracer solution flowing out from the sample flows directly into the measurement tank, it is necessary to consider the residence time of the tracer solution from the sample to the measurement position even when the tracer solution is supplied to the sample at a low flow rate. Disappears. As a result, the tracer solution is supplied to the sample at a low flow rate without providing a flushing mechanism for the tracer solution on the drain side of the sample, and the accuracy of the delay effect due to the diffusion phenomenon (matrix diffusion phenomenon) in the sample is taken into account. Measurement results can be obtained.

  In addition, as a method of measuring the tracer concentration, for example, there is a method of measuring the tracer concentration by extracting a tracer solution from a measurement tank and performing a concentration analysis on the extracted tracer solution. It is not limited.

  The invention according to claim 2 is the tracer test apparatus according to claim 1, wherein the measurement tank is provided with a concentration measuring means capable of measuring the tracer concentration of the tracer solution. The tracer concentration of the introduced tracer solution is measured by a concentration measuring means.

  Here, the measurement method of the tracer concentration by the concentration measuring means provided in the measurement tank is, for example, a iodide ion in an aqueous potassium iodide solution in which a tracer solution containing a tracer substance is composed of an aqueous potassium iodide solution and the sample is passed through. By measuring the change in concentration over time with an ion meter, which is a concentration measuring means, it is possible to grasp the material transfer characteristics of the sample.

  Thus, in the tracer test apparatus of the present invention, the tracer solution flowing out of the sample can be measured immediately by providing the measurement tank with the concentration measuring means for measuring the tracer concentration of the tracer solution. Accurate measurement results can be obtained without considering the dispersion phenomenon.

The invention according to claim 3 is the tracer test apparatus according to claim 1 or 2, wherein the supply means is a supply tank disposed in contact with the water injection surface of the sample, and stored in the supply tank. A supply pump for supplying the tracer liquid to the water injection surface of the sample, and a supply opening facing the water injection surface of the sample is formed in the supply tank, and the tracer solution in the supply tank is It is characterized by being supplied directly to the water injection surface .

  Thus, in the tracer test apparatus of the present invention, the tracer solution can be uniformly supplied to the entire water injection surface of the sample at a uniform pressure by arranging the supply tank in contact with the water injection surface of the sample. .

  The invention according to claim 4 is the tracer test apparatus according to claim 3, wherein the liquid feeding pump is a syringe pump capable of continuously feeding a set flow rate. .

  Thus, in the tracer test apparatus of the present invention, the tracer solution that has flowed out of the sample flows directly into the measurement tank, and it is not necessary to consider the residence time of the tracer solution from the sample to the measurement position. Even if the tracer solution is supplied to the sample at a low flow rate using a syringe pump that can continuously feed the flow rate, the inside of the sample is not equipped with a flushing mechanism for the tracer solution on the drain side of the sample. It is possible to obtain an accurate measurement result in consideration of the influence of the delay effect due to the diffusion phenomenon (matrix diffusion phenomenon).

According to the present invention, it is possible to measure without considering the dispersion phenomenon of tracer solution in until the assay position from the drainage surface of the sample, without providing a flushing mechanism, the tracer solution at low flow rates Since it can supply to a sample and an exact measurement result can be obtained, the mass transfer characteristic of a sample can be grasped exactly.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a schematic diagram showing the overall configuration of the tracer test apparatus of the present embodiment.
In the present embodiment, a case where the present invention is used for a tracer test for grasping a mass transfer characteristic in a rock having a single crack will be described as an example.

[Tracer test]
First, the tracer test will be described.
The tracer test is the measurement result of the tracer solution containing tracer substance penetrating from the water injection surface of the sample, measuring the time-dependent change (breakthrough curve) of the tracer concentration in the tracer solution flowing through the sample and flowing out from the drainage surface. Is a test method for grasping the mass transfer characteristics of the sample (for example, the mass transfer opening width and the dispersion length in the crack).
In addition, the tracer solution of this embodiment is a non-adsorbing potassium iodide aqueous solution, and after passing through the sample, the mass transfer characteristics of the sample are grasped by measuring the change in iodide ion concentration over time. Can do.

[Rock specimen]
Next, a rock sample to be tested in the tracer test using the tracer test apparatus of the present embodiment will be described.
As shown in FIG. 1, the rock sample 50 is a core sample collected from the soil to be investigated. This rock sample 50 is a cylindrical member, and has a water injection surface 51 formed at one end (left side in FIG. 1) and a drainage surface 52 formed at the other end (right side in FIG. 1). . Furthermore, a single crack 53 is formed in the approximate center of the rock sample 50 so as to communicate from the water injection surface 51 to the drainage surface 52. In this embodiment, the rock sample 50 having a diameter of 3 cm, an axial length of 5 cm, and a crack diameter of about 3 cm is used, but the present invention is not limited to this, and samples of various shapes and compositions are used. Can be used.

  The rock sample 50 is covered on its outer peripheral surface by a cylindrical covering member 54 made of epoxy resin. By providing this covering member 54, the tracer solution that has permeated from the water injection surface 51 of the rock sample 50 flows out from the drainage surface 52 without flowing out from the outer peripheral surface. In the present embodiment, the outer peripheral surface of the rock sample 50 is covered with a covering member 54 having a thickness of 1 cm.

[Tracer testing equipment]
Next, the tracer test apparatus of this embodiment will be described.
As shown in FIG. 1, the tracer test apparatus 1 includes a supply tank 10 disposed in contact with the water injection surface 51 of the rock sample 50 and a measurement tank 20 disposed in contact with the drain surface 52 of the rock sample 50. The rock sample 50 is installed in the sample installation region 30 formed between the supply tank 10 and the measurement tank 20, and the tracer solution stored in the supply tank 10 passes through the rock sample 50 and enters the measurement tank 20. It is configured to be stored.

  The supply tank 10 can store the tracer solution supplied from the storage tank 11 of the tracer solution by the liquid feed pump 12 in a sealed state, and the mounting side wall 14 arranged on the sample installation region 30 side has the rock sample 50. A supply opening 13 formed in the same shape as the water injection surface 51 is formed. Thereby, when the rock sample 50 is installed in the sample installation region 30, the water injection surface 51 of the rock sample 50 is exposed from the inside of the supply tank 10 through the supply opening 13, and the tracer in the supply tank 10. The solution is configured to be directly supplied to the water injection surface 51 of the rock sample 50. In this way, the tracer solution is uniformly supplied to the entire water injection surface 51 of the rock sample 50 at a uniform pressure.

In addition, the mounting side wall 14 of the supply tank 10 is formed with a recess 15 into which the end of the rock sample 50 on the water injection surface 51 side can be fitted, and is formed in an annular shape along the outer periphery of the supply opening 13. When the rock sample 50 is installed in the region 30, the end of the covering member 54 of the rock sample 50 is engaged with the recess 15, thereby preventing the supply tank 10 and the rock sample 50 from being displaced.
Further, a flange portion 16 is formed on the outer edge portion of the attachment side wall 14 so as to protrude, and a plurality of attachment holes 17...

  The liquid feed pump 12 for feeding the tracer solution from the storage tank 11 into the supply tank 10 is configured to continuously feed the tracer solution at a low flow rate. A syringe pump with a flow rate of about 0.5 μl / min is used. Further, a water supply valve 18 is provided in the pipe connecting the liquid feed pump 12 and the supply tank 10.

  The measurement tank 20 can store the tracer solution flowing out from the rock sample 50 in a sealed state, and is divided into a measurement water tank 20a and a drain water tank 20b, and the measurement water tank 20a is a sample installation region 30. The drainage water storage tank 20 b is formed through the partition wall 21. The measurement water tank 20a and the drain water tank 20b communicate with each other above the partition wall 21, and the tracer solution stored in the measurement water tank 20a overflows and flows into the drain water tank 20b. It is configured as follows.

  A discharge opening 23 formed in the same shape as the drainage surface 52 of the rock sample 50 is formed in the mounting side wall 22 arranged on the sample installation region 30 side of the measurement water tank 20a. Thereby, when the rock sample 50 is installed in the sample installation region 30, the drainage surface 52 of the rock sample 50 is faced from the inside of the measurement tank 20 through the discharge opening 23, and flows out of the rock sample 50. The tracer solution is configured to flow directly into the measurement tank 20.

Further, in the same manner as the mounting side wall 14 of the supply tank 10, a recess 24 in which the end of the rock sample 50 on the drainage surface 52 side can be fitted is provided on the mounting side wall 22 of the measurement water tank 20 a. When the rock sample 50 is installed in the sample installation region 30, the end of the covering member 54 of the rock sample 50 engages with the recess 24, so that the measurement tank 20 and Deviation of the rock sample 50 is prevented.
Further, a flange portion 25 is formed to protrude from the outer edge portion of the attachment side wall 22, and this flange portion 25 faces each attachment hole 17... Formed in the flange portion 16 of the supply tank 10. In this way, a plurality of mounting holes 26... Penetrates at equal intervals.

  Further, in the upper plate 27 of the measuring tank 20, a through hole 27c is provided at a position corresponding to the upper side of the measuring water tank 20a. An ion meter 40 (“concentration measuring means” in the claims) capable of continuously measuring the change over time of the tracer concentration (iodide ion concentration in the present embodiment) in the tracer solution is inserted into the through-hole 27c from the outside. The ion meter 40 can measure the tracer concentration of the tracer solution in the measurement water tank 20a. The measurement result of the ion meter 40 is configured to be displayed and recorded by output means (not shown).

Further, on the upper plate 27 of the measurement tank 20, a sampling opening 27a for extracting the tracer solution stored in the measurement reservoir 20a for sampling is provided at a position corresponding to the upper side of the measurement reservoir 20a. The tracer solution in the measuring water reservoir 20a can be extracted by removing the lid 27b covering the sampling opening 27a and inserting a syringe or syringe. Yes. In the tracer test apparatus 1 of the present embodiment, the tracer concentration of the tracer solution extracted from the sampling opening 27a (hereinafter sometimes referred to as “sampling solution”) is measured by ICP emission spectroscopic analysis, and the measurement result is obtained. It is configured to display and record by output means (not shown).
The measurement water tank 20a is provided with a magnetic stirrer (not shown) which is a stirring means for constantly stirring the stored tracer solution.

  Further, the inside of the drainage water storage tank 20b is communicated with the inside of the drainage tank 28 provided outside the measurement tank 20 by a drainage pipe 29. The drainage pipe 29 is connected to each of the drainage water storage tank 20b and the drainage tank 28. Since it is connected to the bottom plate, the liquid level of the tracer solution stored in the drainage water storage tank 20b and the drainage tank 28 becomes the same height by the principle of siphon. The tracer solution that has reached the maximum amount of water stored in the drain tank 28 is configured to be drained from the drain tank 28 to the outside of the tracer test apparatus 1. The drain pipe 29 is provided with a drain valve 29a.

  And the rock sample 50 was installed between the attachment side wall 14 of the supply tank 10, and the attachment side wall 22 of the measurement tank 20, and the both ends were fitted to the recessed parts 15 and 24 of each attachment side wall 14 and 22. In this state, a nut 32 is screwed into a bolt 31 inserted into the mounting holes 17 and 26 formed in the flange portions 16 and 25 of the mounting side walls 14 and 22, so that the space between the mounting side walls 14 and 22 is reached. It is fixed to the tracer test apparatus 1 in a sandwiched state.

Next, a tracer test using the tracer test apparatus 1 of the present embodiment will be described.
First, the rock sample 50 is installed in the sample installation region 30 between the supply tank 10 and the measurement tank 20 and fixed so as to be sandwiched between the attachment side walls 14 and 22 of the supply tank 10 and the measurement tank 20.
Furthermore, deionized deaerated water is stored in the supply tank 10, and deionized deaerated water is supplied to the water injection surface 51 of the rock sample 50 through the supply opening 13. At this time, the water supply valve 18 and the drain valve 29a are opened.
Thereby, deionized deaerated water permeates the rock sample 50 from the water injection surface 51, passes through the rock sample 50, and flows into the measurement tank 20 from the drain surface 52 through the discharge opening 23. Thus, after filling the inside of the supply tank 10, the rock sample 50, and the measurement tank 20 with deionized deaerated water, the water supply valve 18 and the drain valve 29a are closed.

Subsequently, with the drain valve 29a closed, the deionized and deaerated water in the supply tank 10 is drained, and the tracer solution is stored in the supply tank 10 after draining.
Further, the liquid feed pump 12 is driven to supply the tracer solution in the storage tank 11 to the supply tank 10 at a low flow rate, and the water supply valve 18 and the drain valve 29a are opened.

  Thereby, the tracer solution penetrates into the rock sample 50 from the water injection surface 51, passes through the rock sample 50, and flows into the measurement tank 20 from the drainage surface 52 through the discharge opening 23. In this way, the tracer solution that has passed through the rock sample 50 is stored in the measurement water tank 20 a of the measurement tank 20.

Then, the change with time of the tracer concentration is measured by the ion meter 40 in the measuring water tank 20a, and the measurement result is displayed and recorded by an output means (not shown).
At this time, in the tracer test apparatus 1 of this embodiment, the measurement tank 20 is arranged in contact with the rock sample 50, and the tracer solution discharged from the rock sample 50 is an ion meter 40 that measures the tracer concentration of the tracer solution. Will flow directly into the measurement reservoir 20a. Thereby, it is not necessary to consider the dispersion phenomenon of the tracer solution between the rock sample 50 and the measurement position, so that the reliability of the measurement result can be improved.

  In addition, since the tracer solution flowing out from the rock sample 50 directly flows into the measurement reservoir 20a of the measurement tank 20, even when the tracer solution is supplied to the rock sample 50 at a low flow rate, the measurement position from the rock sample 50 is measured. It is not necessary to consider the residence time of the tracer solution during Accordingly, the tracer solution is supplied to the rock sample 50 at a low flow rate without providing a flushing mechanism of the tracer solution on the drainage surface 52 side of the rock sample 50, and a delay due to a diffusion phenomenon (matrix diffusion phenomenon) in the rock sample 50 is performed. Accurate measurement results can be obtained in consideration of the effects of effects.

  In addition, the tracer solution in the measurement water tank 20 a sequentially overflows from the measurement water tank 20 a and flows into the drain water tank 20 b, and then flows into the drain tank 28 through the drain pipe 29 from the drain water tank 20 b. Later, it will be drained to the outside. That is, since the tracer solution can be sequentially drained while keeping the measurement tank 20 sealed, volatilization of the tracer solution in the measurement tank 20 can be prevented. Thereby, since the tracer concentration does not change due to volatilization of the tracer solution, it is possible to reliably grasp a minute change in the tracer concentration.

Furthermore, in the tracer test apparatus 1 of the present embodiment, the time-dependent change in the tracer concentration is measured by the ion meter 40, and the measurement reservoir is passed through the sampling opening 27a of the measurement tank 20 at a frequency of about three times a day. About 5 ml of the sampling solution is extracted from the tracer solution in the tank 20a by a syringe or the like, the tracer concentration of the extracted sampling solution is measured by ICP emission spectroscopic analysis, and the measurement result is displayed and recorded by output means (not shown). .
When the sampling solution is extracted, the same amount of deionized degassed water is replenished to the measurement water tank 20a, and the influence of this dilution is grasped from the extracted amount and the concentration thereof, and the measurement water tank 20a. Correct the tracer concentration of the tracer solution inside.

  In the measurement of the tracer concentration in the sampling solution, the reliability of the measurement result can be improved without considering the dispersion phenomenon of the tracer solution in the measurement tank 20, and the tracer solution is supplied to the rock sample 50 at a low flow rate. Thus, an accurate measurement result can be obtained in consideration of the influence of the delay effect due to the diffusion phenomenon in the rock sample 50.

  Thus, the mass transfer characteristic of the rock sample 50 is grasped by comparing the change with time of the tracer concentration measured using the tracer test apparatus 1 of the present embodiment with the theoretical curve.

Therefore, according to this onset bright, it is possible to measure without considering the dispersion phenomenon of tracer solution between the drainage surface 52 of the rock sample 50 to the measuring position, without providing a flushing mechanism, at low flow rates Since the tracer solution can be supplied to the sample to obtain an accurate measurement result, the mass transfer characteristics of the rock sample 50 can be accurately grasped.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, in the present embodiment, the substance transfer characteristics in rocks are obtained, but the substance transfer characteristics of various samples can be grasped using the tracer test apparatus 1 of the present invention.
Further, the configuration of the tracer solution is not limited, and can be appropriately changed according to the composition of the sample.
Furthermore, in the present embodiment, the tracer concentration of the tracer solution is measured by analysis using the ion meter 40 and sampling, but the tracer concentration may be measured by only one measuring means.

It is the schematic which showed the whole structure of the tracer test device of this embodiment. It is the schematic which showed the whole structure of the conventional tracer test device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tracer test apparatus 10 Supply tank 20 Measuring tank 20a Measurement water tank 20b Drain water tank 28 Drain tank 30 Sample installation area 40 Ion meter (concentration measuring means)
50 Rock Sample 51 Water Injection Surface 52 Drainage Surface 53 Single Crack 54 Covering Member

Claims (5)

A supply means capable of storing a tracer solution containing a tracer substance, and capable of supplying the tracer solution to a water injection surface of a sample;
A measuring tank disposed in contact with the drainage surface of the sample,
In the measurement tank, a discharge opening facing the drainage surface of the sample is formed,
The supplied from the supply means to the water injection surface of the sample was the tracer solution, the tracer test apparatus characterized by being configured to pass through the sample to flow directly into the measuring tank from the waste water surface . The measuring tank is provided with a concentration measuring means capable of measuring the tracer concentration of the tracer solution,
The tracer test apparatus according to claim 1, wherein the tracer concentration of the tracer solution that has flowed into the measurement tank is configured to be measured by the concentration measuring unit. The supply means includes a supply tank disposed in contact with the water injection surface of the sample;
And liquid feed pump for feeding the tracer liquid stored in the supply tank to the water injection surface of said sample is composed of,
In the supply tank, a supply opening facing the water injection surface of the sample is formed,
The tracer test apparatus according to claim 1 or 2, wherein the tracer solution in the supply tank is directly supplied to the water injection surface of the sample .   The tracer test apparatus according to claim 3, wherein the liquid feeding pump is a syringe pump capable of continuously feeding a set flow rate. A tracer test method using the tracer test apparatus according to any one of claims 1 to 4,
Filling the inside of the measuring tank with deionized deaerated water;
Supplying the tracer solution from the supply means to the water injection surface of the sample;
The tracer solution that has passed through the sample flows directly from the drainage surface into the measuring tank;
Measuring the tracer concentration in the measuring tank;
A tracer test method comprising:

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