JP2741467B2 - Groundwater sampling apparatus and water sampling method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groundwater sampling technique for sampling groundwater in a pressure-insensitive state without disturbing the environment in a sampling section. The present invention relates to a groundwater sampling apparatus in which a casing pipe having an inner packer, an inner probe having an inner packer and inserted into the casing pipe, and a sampling capsule attached to a lower end of the inner probe, and a sampling method using the same. is there. This technique is particularly useful for collecting groundwater present in deep formations.

[0002]

2. Description of the Related Art Conventionally, groundwater sampling techniques conventionally used include a continuous sampling method using a pump-up and a batch sampling method using a sampling capsule or the like. The continuous water sampling method is a method in which a pump is installed on a probe inserted into a borehole, and groundwater in the water sampling section is continuously pumped up to the ground. In contrast, the batch sampling method attaches a depressurized sampling capsule to the probe inserted into the borehole, and utilizes the pressure difference between the pressure in the sampling capsule and the pore water pressure of the stratum in the sampling section. This method collects groundwater in a sampling capsule and recovers it to the ground.

[0003]

With the recent progress in the use of underground space, it has become important to more accurately grasp the characteristics of groundwater existing in deep geological formations. For this purpose, it is desirable that the groundwater be collected in a pressure-insensitive state (a state in which the pressure at the original position is maintained and does not come into contact with the atmosphere). Moreover, it is necessary to collect formation water (water originally existing in gaps in the formation). However, in the borehole and the surrounding stratum, drilling water from drilling of the borehole remains, or groundwater from different strata is mixed,
There is no guarantee that the groundwater in the sampling section is formation water.
The conventional methods as described above have been applied to large depths in recent years, but currently have the following problems.

[0004] First, the continuous water sampling method has a higher working efficiency than the batch water sampling method, but the pumping capacity of the pump is about several hundred meters in the existing technology, so that the groundwater level in the borehole is reduced by the pump head. If it falls below the capacity, it becomes impossible to collect water. Structurally, it is impossible to collect groundwater in a pressure-inactive state.
Furthermore, since water is continuously collected for a long time, the load applied to the pump is large, and the durability of the pump is significantly reduced.

[0005] Next, the batch type water sampling method has the advantage of not disturbing the in-situ environment as compared with the continuous water sampling method. However, since the inside of the water sampling capsule is initially in a depressurized state, it is strictly inactive under pressure. It does not take water in the state. In addition, in order to collect formation water from a sampling section, it is necessary to discharge groundwater several to several tens times the volume of the sampling section in advance.Therefore, groundwater collected in a sampling capsule must be repeatedly collected to the ground. The work efficiency is greatly reduced as the depth increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique for efficiently collecting groundwater existing in a deep geological formation using a borehole in a pressure-inactive state without disturbing the environment of a sampling section. To provide.

[0007]

SUMMARY OF THE INVENTION A groundwater sampling apparatus according to the present invention has a casing in which an upper impermeable packer , a strainer, and a lower impermeable packer are arranged at the lower end in that order, and a drain port is provided on a side wall of the intermediate section. a pipe, and an inner probe to be inserted into the casing pipe, are provided with a water sampling capsule attached to the lower end of the inner probe. Here, the water sampling capsule is provided with a portion for introducing groundwater flowing from a strainer between the upper water-impervious packer and the lower water-impervious packer , a capsule body communicating therewith, and a valve mechanism that can open and close the capsule body. I have. Further, the inner probe is located above the drain port on the outer periphery of the middle portion.
The inner packer provided at the position and the inner probe intervened through the pump and valve rising from the water sampling capsule
A pipe penetrating through the side wall to the outside of the inner probe, a storage tank for partial water sampling, a pipe extending from the water sampling capsule to the storage tank via a valve, and a partial water sampling provided in the storage tank. A dilation balloon, a pipe extending from the storage tank to the ground, and a pipe for introducing a high-pressure fluid into the dilation balloon.

In the method of the present invention, the above apparatus is installed in a borehole, and the upper and lower impermeable packers are expanded to define a water sampling section. Lead to groundwater in the water adopted in the next section in the capsule body from the water sampling inlet portion, and drainage to the outside of the inner probe by the pump, preliminary drainage further from the drain port to the outside of the casing pipe. Further, the inner packer is expanded to introduce a part of the groundwater into the storage tank for partial water sampling using pore water pressure, and to introduce and expand the high-pressure fluid into the expansion balloon to expand the inside of the storage tank. Partial water sampling is conducted by guiding groundwater to the ground. Then, when it is determined that the partly sampled groundwater is formation water, the valve mechanism of the water sampling capsule is driven so that the capsule body is closed and water is sampled.

[0009]

The inner packer blocks the upper groundwater from flowing into the water sampling section even when the liquid level is pressurized inside the inner probe. Preliminary drainage is performed by discharging the groundwater in the sampling section to the outside of the borehole through the drain port of the casing pipe, instead of pumping the groundwater to the ground. Partial water sampling is performed by using a pore water pressure of groundwater to temporarily introduce groundwater into a storage tank for partial water sampling, and expand the expansion balloon to pressurize the internal groundwater instead of using a pump. . During drainage and partial sampling, groundwater circulates through the sampling capsule and is constantly replaced by fresh groundwater. Therefore, when it is determined that the partially sampled groundwater is formation water, the inside of the sampling capsule is filled with formation water as a matter of course, and batch collection in the pressure-inactive state is performed by closing the valve mechanism. Water is complete.

[0010]

FIG. 1 is an overall configuration diagram showing an embodiment of a groundwater sampling apparatus according to the present invention. This device mainly includes a casing pipe 10, an inner probe 30 inserted into the inside thereof, and a water sampling capsule 60 attached to a lower end of the inner probe 30. FIG. 2 shows a state where the casing pipe 10 and the inner probe 30 are separated. FIG. 3 is an overall structural view of the water sampling capsule 60.

The casing pipe 10 has an upper water-impervious packer 12, a strainer 13, and a lower water-impervious packer 14 arranged in that order below a cylindrical pipe body 11, and the pipe body 11 The drain port 15 is provided on the side wall. Further, a connection port 16 for pressurizing the upper and lower water-impervious packers is provided on the side wall of the casing pipe 10, and the upper water-impervious packer 1 is
2 and an upper / lower impermeable packer expansion pipe 17 leading to the lower impermeable packer 14 are connected. Casing pipe 10
The upper end opening of the casing can be closed by a casing pipe closing coupler 18, and a first valve 20 and a first pressure gauge (for pneumatic) 21 are connected to a pressurizing pipe 19 in the casing pipe passing through the closing coupler 18. Is provided.

The inner probe 30 is provided with a first inner packer 32 provided at the center of the outer periphery of a cylindrical probe main body 31, second and third inner packers 33 and 34 provided at the lower part of the outer periphery, and provided at the upper part. Reservoir 3 for partial water sampling
5 and a dilation balloon 36 provided therein for partial water sampling
It has. The preliminary drain / partial water sampling pipe 37 rises from the water sampling capsule 60 provided at the lower end, and reaches the first inner packer 32 via the water supply / drain pump 38, the second valve 39, and the second pressure gauge 40. A third valve 42 and a third pressure gauge 43 are provided between the second and third inner packers 33 and 34 and the casing pipe pressure transmission port 41 at the upper end.
Are connected by a casing pipe pressure transmission pipe 44 having Further, the second and third branches are branched from the pressure transmission pipe 44.
And a fourth valve 46 and a fourth pressure gauge 47 are provided on the pipe between the inner packers 33 and 34 to reach the upper and lower impermeable packer pressurizing ports 45. Further, a fifth pressure gauge 48 is provided in the middle of the preliminary drainage / partial water sampling pipe 37, branched from the suction side of the water supply / drainage pump 38, and stored through a fifth valve 49 and a sixth pressure gauge 50. Tank 3
Connect to 5. A pipe is connected from the discharge side of the water supply / drain pump 38 to the storage tank 35 for partial water sampling, and a sixth valve 51 and a three-way valve 52 are provided. I do. The distance between the casing pipe pressure transmission port 41 and the dilatation balloon 36 is the seventh.
The storage tank 35 and the water sampling port 55 for partial water sampling are connected by a pipe having an eighth valve 56. Reference numeral 57 is a composite cable.

[0013] As shown in FIG.
Above the capsule main body 61, it is composed of a cylindrical portion in which the capsule attaching / detaching portion 62 and the motor housing 63 are continuous, and a filter 64 located thereunder. Capsule body 61
Is hermetically separated by a capsule bottom lid 65 and a capsule top lid 66, and a lower water sampling shaft 67 slidably penetrates the center thereof. The lower part of the water sampling lower shaft 67 has a hollow structure, and is fixed to the filter 64 at the lower end. A lower water inlet 68 is formed in the capsule bottom lid 65, an upper water inlet 69 is formed in the lower water sampling shaft 67 near the capsule upper lid 66, and an opening / closing valve is provided at the upper end of the lower water sampling shaft 67. 70 are provided, and these serve as a valve mechanism. A valve opening / closing shaft 71 is provided above the opening / closing valve 70, and the valve opening / closing shaft 71 is connected to a lower end of a hollow upper shaft 72 for water sampling. In the motor housing 63, a motor / gearbox 73 for driving the upper shaft 72 for water sampling is incorporated. This water sampling probe 60
The upper end is an inner probe connection portion (connection portion to a pre-drainage / partial water sampling pipe) 74.

Next, an operation procedure for collecting water using the apparatus of the present invention will be described. The operation is usually performed by first inserting the device into the borehole, setting the water sampling section (FIGS. 4 to 6), then performing preliminary drainage (FIG. 7), and partially extracting water during the preliminary drainage period (FIGS. 8 and 9). ), And batch-type water sampling with a water sampling capsule (Fig. 1)
0), and finally, in the order of device recovery. In each of the valves shown in FIG. 4 to FIG. 9, a white symbol indicates an open state, and a black symbol indicates a closed state.

[Insert the device into the borehole] The casing pipe 10 (in FIG. 2A, the closing coupler 18 at the upper end, the pressurizing pipe 19, and the first valve 20 and the first pressure gauge 21 associated therewith are removed. Is inserted into the borehole, and after reaching a predetermined depth, it is fixed on the ground. The inner probe 30 (portion B in FIG. 2) is inserted into the casing pipe 10. The inner probe 30 automatically stops at a predetermined depth. At this time, the water level in the casing pipe 10 also rises to the groundwater level in the borehole and stabilizes. After the above operations are completed, the closing coupler 18 is hermetically attached to the upper end of the casing pipe 10, and the pressure pipe 19, the first valve 20, and the first pressure gauge 21 are attached. By these operations, the device insertion is completed, and the state shown in FIG. 1 is obtained.

[Setting of Sampling Section—Part 1] As shown in FIG. 4, the second valve 39 is opened, and the groundwater in the borehole is pumped up by using the water supply / drainage pump 38. In this case, the groundwater passes from the strainer 13 and the water sampling capsule 60 to the preliminary drainage / partial water sampling pipe 37, passes through the fifth pressure gauge 48 and the second pressure gauge 40, and passes through the first inner packer 3.
Extend 2 Confirmation of the expansion of the first inner packer 32 is performed by the second pressure gauge 40. Thereafter, the second valve 39 is closed, and the operation of the water supply / drainage pump 38 is also stopped.

[Setting of Water Sampling Section-Part 2] As shown in FIG. 5, the first valve 20 and the third valve 42 are opened. Then, the inside of the casing pipe 10 is pressurized by air pressure by the pressurizing pipe 19 in the casing. With pressurization, the groundwater in the casing pipe 10 expands the second and third inner packers 33 and 34 via the third valve 42. The confirmation of the packer expansion is performed by the third pressure gauge 43. Second and third
After the expansion of the inner packers 33 and 34 is completed, the third valve 42 is closed. Thereby, both inner packers 33,
A closed section is set between 34. Then, the upper / lower impermeable packer pressurizing port 45 and the upper / lower impermeable packer pressurizing connection port 16 are connected, and the setting of the piping system for expanding the impermeable packer is completed.

[Setting of Water Sampling Section-Part 3] The casing pipe 10 is already pressurized by the operation described in the preceding section. As shown in FIG. 6, when the fourth valve 46 is opened, the groundwater in the casing pipe 10 receives the casing pipe pressure transmission port 41, the pressure transmission line 44, the fourth valve 46, the fourth manometer 47, The upper liner packer 12 and the lower liner packer 14 are expanded via the lower liner packer pressurizing port 45, the upper / lower liner packer pressurizing connection port 16, and the upper / lower liner packer expansion line 17. Confirmation of expansion of both impermeable packers 12 and 14
The measurement is performed by the pressure gauge 47. After confirming the expansion of both the impermeable packers 12 and 14, the fourth valve 46 and the first valve 20 are closed,
Pressurization by air pressure from the ground also stops. By the above operation, a water sampling section closed by the impermeable packer can be set at an arbitrary position in the borehole.

[Preliminary Drainage] As shown in FIG. 7, the second valve 39 and the sixth valve 51 are opened. The three-way valve 52 opens to the preliminary drain port 53 side. By this operation, the first inner packer 32 contracts. Further, since the preliminary drain port 53 is opened by the above operation, the groundwater in the casing pipe 10 recovers to the same level as the groundwater level in the borehole. After the contraction of the first inner packer 32 is completed, the second valve 39 closes. By operating the water supply / drainage pump 38, the strainer 1 is moved from the water sampling section closed by the upper and lower impermeable packers 12 and 14.
3. Preliminary drainage / partial water sampling line 37, fifth pressure gauge 4
8. Discharge groundwater into the casing pipe 10 via the supply / drain pump 38, the sixth valve 51, the three-way valve 52, and the preliminary drain port 53. In addition, the groundwater in the casing pipe 10 rises by the above operation.
Since 5 is open, it is discharged into the borehole.

[Partial Sampling-Part 1] Partial sampling is performed to temporarily discharge groundwater to the above-ground part in order to confirm the change in groundwater quality during the preliminary drainage period. Therefore, preliminary drainage is temporarily suspended. The first inner packer 32 is expanded in the same manner as the operation described in the section [Setting of water sampling section-Part 1]. On this occasion,
Since it is considered that the pressure in the casing pipe 10 increases, the first valve 20 is opened to release the pressure to the ground (see FIG. 8). The fifth valve 49 and the eighth valve 56 are opened, and groundwater is stored in the partial water sampling storage tank 35 by using the potential (pore water pressure) of the water sampling section. At this time, the groundwater passes through the preliminary drainage / partial water sampling line 37, the fifth pressure gauge 48, the fifth valve 49, and the sixth pressure gauge 50. The fifth valve 4
By closing 9, opening the sixth valve 51, and opening the three-way valve 52 to the storage tank 35 side, groundwater can also be stored in the storage tank 35 using the water supply / drain pump 38. Confirmation of the storage amount of the groundwater in the partial water sampling storage tank 35 is performed by the sixth pressure gauge 50. After confirming the storage amount, the fifth valve 49 is closed (or the three-way valve 52 is closed and the water supply / drain pump 3
8 stop).

[Partial Sampling-Part 2] The seventh valve 54 is opened. The inside of the casing pipe 10 is pressurized from the casing pipe pressurizing pipe 19 using air pressure. Then, the groundwater in the casing pipe 10 is pressurized, and the expansion balloon 36 for partial water sampling is expanded via the seventh valve 54 (see FIG. 9). As a result, the volume in the storage tank 35 for partial water sampling is reduced, and the groundwater in the storage tank 35 is discharged from the eighth valve 56.
Water can be collected from the water sampling port 55 for partial water sampling via.
If the amount of water sample is not enough, repeat the above operation.

In the above preliminary drainage and partial drainage steps, the water sampling capsule 60 connected to the lower end of the inner probe 30 operates the motor / gear box 73 as shown in FIG. The shaft 72, the valve opening / closing shaft 71, and the lower shaft 67 for sampling water and the filter 64 are in a lowered state. This passes from the filter 64 through the lower water sampling shaft 67, the lower water inlet 68 of the capsule bottom lid 65, the capsule body 61, the upper water inlet 69, the opening / closing valve 70, the valve opening / closing shaft 71, the upper shaft 72 for water sampling, The headrace is connected to the inner probe connection (pump connection for drainage pump) 74, and is in a state where groundwater can flow in. In this state, preliminary drainage and partial water sampling are performed by the above-described operation procedure. The flow of groundwater is indicated by arrows. Preliminary drainage is repeatedly performed until it can be determined that it is formation water based on the analysis of partially collected groundwater.

[Batch Sampling] When it is determined that the partially sampled groundwater is formation water, the motor / gearbox 73
And raise each connected shaft. When the water sampling upper shaft 72 is pulled up, the center pin 75 of the valve opening shaft 71 fixed thereto is separated from the on-off valve 70. The on-off valve 70 closes the upper part of the water sampling lower shaft 67 by a built-in spring.
When the water sampling upper shaft 72 is further pulled up, the valve opening / closing shaft 71 is connected to the valve opening housing 76, and the water sampling lower shaft 67 is pulled up. As a result, the water sampling port below the water sampling lower shaft 67 is connected to the lower water inlet 68.
The shaft stopper 77 comes into contact with the capsule bottom lid 65, and each shaft stops. The series of shaft movements seals the inside of the capsule body 61. The groundwater in the capsule body 61 is in a pressure-inactive state, and the state is maintained even if it is collected on the ground.

[Recovery of Apparatus] Each valve in the inner probe is opened, each packer is contracted, and the water sampling capsule is recovered on the ground together with the inner probe. One side of the split outer tube of the capsule attaching / detaching portion 62 is removed, and a shaft fixing screw 78 connecting the upper water sampling shaft 72 and the valve opening / closing shaft 71 is removed. Then, the motor / gear box 73 is operated again, and the upper shaft 7 for water sampling is operated.
2 is lifted and separated from the valve opening / closing shaft 71. The remaining outer tube of the capsule attaching / detaching portion 62 is removed, and the capsule main body 61 is removed.
Collect.

In the apparatus of the above embodiment, since the casing pipe is used for the expansion system water supply pipe of the impermeable packer, the impervious packer can be expanded in a short time with less resistance in the pipe than a conventional hose or the like. By the way, at a depth of several hundred m or less, the conventional method requires about 6 to 24 hours for expansion and contraction of the packer, but the above apparatus can complete the operation in about 1 hour. And, since the method of expanding and contracting the inside of the hole using the water in the hole is adopted, even if the groundwater level of the borehole decreases, the packer can be reliably expanded and contracted. Groundwater contamination can be minimized. Furthermore, there is no need to install a water supply hose or a signal cable outside the casing pipe, and there is no risk of damage to the hose or the like due to contact with the borehole wall.

[0026]

According to the present invention, the groundwater in the water sampling section separated by the impermeable packer is preliminarily drained through the water sampling capsule.
In a state in which water is partially collected and completely replaced with formation water, the capsule body is closed by a valve mechanism to confine formation water. Can be collected. Also, since the inner volume of the capsule body can be set to about 5 to 6 liters,
With one sampling, the amount of groundwater required for water quality analysis can be secured, and the work time can be greatly reduced.

Since the present invention is a partial water sampling method that does not require a pump, there is no need to collect groundwater up to the ground at the time of preliminary drainage, and the preliminary drainage can be achieved only by drainage in the hole. For this reason, the discharge amount per unit time is several times to several tens times as compared with the surface drainage, and the working time can be greatly reduced. Since the water supply and drainage pump does not require a high head, the amount of groundwater discharged per unit time is greatly increased, and the load on the motor can be reduced, so that the pump life is greatly extended and economical.

According to the present invention, after the device is inserted into the borehole, preliminary drainage, partial water sampling, and batch water sampling can be performed by simple operations, and work can be efficiently performed until formation water is collected. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory view for assembling a water sampling apparatus.

FIG. 2 is an exploded view of the water sampling device.

FIG. 3 is an overall structural view of a water sampling capsule.

FIG. 4 is an explanatory diagram of a procedure for setting a water sampling section-part 1;

FIG. 5 is an explanatory diagram of a setting procedure of a water sampling section-part 2;

FIG. 6 is an explanatory diagram of a setting procedure of a water sampling section-part 3.

FIG. 7 is an explanatory diagram of a preliminary drainage procedure.

FIG. 8 is an explanatory diagram of a partial water sampling procedure-part 1.

FIG. 9 is an explanatory diagram of a partial water sampling procedure-part 2;

FIG. 10 is an explanatory view of the operation of the water sampling capsule.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing pipe 12 Upper impervious packer 14 Lower impervious packer 15 Drainage port 18 Casing pipe closing coupler 19 Pressurized pipe in casing pipe 30 Inner probe 32, 33, 34 Inner packer 35 Storage tank for partial sampling 36 Partial sampling Expansion balloon 37 Preliminary drainage / partial water sampling line 41 Casing pipe pressure transmission port 55 Partial water sampling port 60 Water sampling capsule 61 Capsule body 64 Filter 68 Lower water inlet 69 Upper water inlet

Claims (2)

(57) [Claims] 1. An upper impermeable packer and a strainer at a lower end.
And a lower water-impervious packer in that order, a casing pipe provided with a drainage port on an intermediate side wall, an inner probe inserted into the casing pipe, and attached to a lower end of the inner probe. A water sampling capsule, wherein the water sampling capsule is provided with an introduction portion of groundwater flowing from a strainer between the upper water-impervious packer and the lower water-impervious packer , a capsule body communicating with the same, and the capsule body can be opened and closed. The inner probe is provided with the drain port on the outer periphery of an intermediate portion thereof.
And the inner packer located above the
In through the rising pumps and valves from serial water sampling capsule
A pipe penetrating through the side wall of the inner part of the inner probe to reach the outside of the inner probe, a storage tank for partial water sampling, a pipe extending from the water sampling capsule to the storage tank via a valve, and provided in the storage tank. A groundwater sampling apparatus comprising: an expansion balloon for partial water sampling; a pipe reaching the ground from inside the storage tank; and a pipe for introducing a high-pressure fluid to the expansion balloon. 2. A set up apparatus of claim 1, wherein in the borehole, defining a water section adopted by expanding the upper and lower water barrier packers capsule from water sampling inlet portion groundwater in adopting water section body And drained out of the inner probe by a pump, pre-drained from the drainage port to the outside of the casing pipe , expanded the inner packer, and introduced part of the groundwater into the storage tank for partial sampling using pore water pressure. Introducing a high-pressure fluid into the dilatation balloon to expand and introduce the groundwater in the storage tank to the ground, perform partial sampling, and determine that the partially sampled groundwater is formation water. A groundwater sampling method that drives the capsule to keep the capsule body in a sealed state.