JP2010174559A - Method for hydraulic fracture test and measuring device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hydraulic fracture test which is performed in a bore hole, so as to avoid degradation in the accuracy of measurement caused by impurities contained in the water in the hole. <P>SOLUTION: In the method, a water-cutoff means 4A and the measuring device 10A which has a water pressure sensor 123 and a flow rate sensor 122 are arranged at the tip side of a boring rod 5. Then, after the water-cutoff means 4A is inserted in the bore hole 3A until it reaches the area to be tested and this area is defined from another area pressure is applied by sending high-pressure water, so as to measure fluctuations in the hydraulic pressure in the area to be tested and the amount of water supply of the high-pressure water by the measuring device. Injection water which is injected into the area to be tested is filled into the measuring device 10A in advance, and a cylinder-shaped injection water chamber 124 separated by a piston 125 in the inner space side of the boring rod 5 is provided to the measuring device 10A. Then, only the injection water squeezed out by the piston 125 is supplied as high-pressure water to the area to be tested by the application of pressure to the water in the hole of the boring rod 5, so that the fluctuations in the hydraulic pressure of the infusion water and the amount of water supplied along with the sound in the hole during crushing are measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydraulic fracturing test method and a measuring device thereof, and more particularly, to a hydraulic fracturing test method carried out in a borehole for measuring a stress state of a rock in a deep underground and a measuring device used for the test method.

  Japanese Patent Application Laid-Open No. 63-308186 discloses a method for measuring pressure change and AE (acoustic emission) generated during the formation, opening, and closing processes of cracks generated in rocks in deep underground using pressurized fluid. The hydraulic fracturing test method as described in the Gazette etc. is widely known, measurement of crustal stress, determination of appropriate pressure of rock mass injection in grouting of dam foundation rock mass, measurement of limit pressure for occurrence of leak holes, It is used to prevent landslides and ground collapse.

  The simplified vertical cross-sectional view of the ground in FIG. 3 shows an example of the implementation status of such a hydraulic fracturing test method, and extends from the high-pressure pump 8 on the ground side into the borehole 3B excavated to the measurement depth. A water supply pipe 6 having a measuring device 10C for hydraulic crushing test and a water shielding means 4B is inserted at the tip, and is partitioned by a water shielding means 4B comprising packers 41 and 42 provided at the tip side of the measuring device 10C. As a result, the high pressure pump 8 is driven into the hydraulic crushing chamber 32 formed between the inner wall surface of the boring hole 3B and the outer surface of the water supply pipe 6, and high pressure water is sent through the water supply pipe 6 to crush the inner wall surface of the boring hole 3B. These pressure processes are measured by the measuring device main body 12 </ b> C in the water supply pipe 6.

  In recent years, a hydraulic crushing test method as described in Japanese Patent Application Laid-Open No. 2007-9645 has become widespread. FIG. 4 shows a longitudinal sectional view of the implementation status of the test method. In this test method, a pilot hole excavator (not shown) is inserted into the bore rod 5 inserted into the bore hole 3A. Then, a feature is that a test hole 30 having a diameter smaller than the diameter of the boring hole 3A is excavated in the hole bottom of the boring hole 3A, and a hydraulic crushing test is performed in this portion.

  That is, after the test hole 30 is excavated, the pilot hole excavator is lifted up, and the measuring device 10B having the measuring device main body 12B on the proximal end side is inserted to the tip of the boring rod 5 and the water shielding means 4A provided on the distal end side. After the packer 40 is expanded to close the hole of the test hole 30, high-pressure water is supplied into the test hole 30, and the amount of water supply and the change time of the internal water pressure are measured by the measuring device main body 12 </ b> B.

  Thus, by making the test hole 30 smaller in diameter than the boring hole 3A and performing the hydraulic crushing test at that part, the volume of the part to be crushed and the capacity of the high-pressure water to be injected can be reduced. Therefore, it is possible to increase the rigidity of the measurement system having the measurement device, and it is easy to realize more accurate measurement.

  However, in the conventional hydraulic crushing test method described above including the test method for providing the test hole 30 having a small diameter as described above, impurities contained in the water in the hole may cause an error in the flow rate measurement of the high-pressure water. there were.

JP-A 63-308186 JP 2007-9645 A

  The present invention is intended to solve the above-described problems, and it is possible to avoid a decrease in measurement accuracy due to impurities contained in the bore water in a hydraulic crushing test performed in a bore hole. This is the issue.

  Accordingly, the present invention provides a water blocking means for partitioning a region where high pressure water is injected in a bore hole and another region on the tip side of a hollow boring rod, and a measuring device having at least a water pressure measuring unit and a flow rate measuring unit. After inserting the water blocking means up to the test target area in the borehole and partitioning this test target area from other areas, the test target area is sent while sending high pressure water through the boring rod. In the hydraulic crushing test method in which pressure is applied to the inner wall of the borehole and at least the fluctuations in water pressure and the amount of high-pressure water delivered are measured with a measuring device, the measuring device is injected into the testing target region. Is provided with a cylinder-shaped injection water chamber that is pre-filled with injection water and is partitioned by a piston from the inner space side of the boring rod. Only the injected water that was pushed out by sliding the piston by being pressurized is fed to the test area as high-pressure water, and the amount of this injected water is measured together with the sound in the hole during crushing by the flow rate measuring means. It was characterized by doing.

  As described above, in the conventional test method that pressurizes and crushes the area to be tested by pressurizing the borehole water in the borehole, impurities contained in the borehole cause an error in the flow measurement of high-pressure water. In contrast, the measuring device used for the hydraulic fracturing test in the present invention is provided with a cylindrical injection water chamber filled with injection water, and supplies water as high-pressure water to the test target region side and measures the amount of water supply. As a matter of fact, a decrease in measurement accuracy can be avoided by using injected water that does not contain impurities. At the same time, by recording the sound in the hole during crushing, the extraction accuracy of the flow rate change point can be increased.

  In addition, in this measurement method, by adding a procedure for adsorbing and removing iron oxide impurities from the borehole water in the boring rod using a magnetic filter, factors that easily affect flow measurement are preliminarily determined. This makes it easier to avoid a decrease in measurement accuracy.

  Furthermore, in the hydraulic crushing test method described above, as the injection water to be filled in the injection water chamber, it is characterized by using a water whose viscosity is adjusted to a predetermined range by adding a predetermined additive to fresh water, More accurate flow rate measurement is likely to be realized.

  Furthermore, in the above-described hydraulic crushing test method, the measuring device includes an outer tube connected to the tip of the boring rod, an injection water chamber, and recovery to the ground side by lifting and hanging operations in the boring rod. If it is characterized by comprising a measuring apparatus main body that can be inserted into and removed from the outer tube, the adjustment and maintenance of the measuring apparatus including the refilling operation of the injected water can be facilitated.

  In addition, in the above-described hydraulic fracturing test method, if the measurement device is provided with a recording means for recording all measurement data, the measurement data is transferred to the ground side. It is not necessary to provide a cable for sending, and in this case, if the measurement data includes the recorded data of the sound in the hole, the extraction accuracy of the flow rate change point can be increased.

  In addition, a measuring apparatus used in the above-described hydraulic fracturing test method, comprising a flow rate measuring means, a cylinder-shaped injection water chamber pre-filled with injection water and partitioned from the internal space side of the boring rod by a piston And at least the flow rate measuring means is fed into the test area as high-pressure water only from the injected water that is pushed out by sliding the piston when the bore water in the boring rod is pressurized. If it is set as the measuring apparatus characterized by measuring the amount of water flow of injection water, each function mentioned above will be exhibited reliably by using this for a hydraulic crushing test.

  According to the present invention, the measuring device used for the hydraulic crushing test is provided with a cylindrical injection water chamber filled with injection water, and only the injection water is supplied as high-pressure water to the test target region side to measure the amount of water supply. Therefore, it is possible to avoid a decrease in measurement accuracy due to impurities contained in the water in the hole.

The fragmentary longitudinal cross-section which shows embodiment of this invention. The longitudinal cross-sectional view which expanded the measuring apparatus main body of FIG. The longitudinal cross-sectional view which shows the test implementation status of a prior art example. The longitudinal cross-sectional view which shows the test implementation status of a prior art example.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a partial longitudinal sectional view of a state in which a measuring device 10A used in the hydraulic fracturing test method according to the present embodiment is connected to the tip of a boring rod 5. This measuring device 10A comprises a substantially cylindrical outer tube 11 connected to the tip of the boring rod 5, and a substantially columnar measuring device main body 12A that is inserted and arranged therein and includes various measuring means. A water shielding means (not shown) is connected to the distal end side.

  The measuring device main body 12A is inserted and arranged in the outer tube 11 as a logger for measuring flow rate and pressure. The measuring device main body 12A is provided with a hook 128 on the base end side and is suspended by a traveling tool or the like. It is possible to collect on the ground side by way of the vias, and it is fed from the ground side to the tip side of the boring rod 5, and the stepped portion 120 on the outer peripheral surface is brought into contact with the stopper 111 provided on the inner peripheral surface of the outer tube 11. -It can be locked and placed at the measurement position.

  FIG. 2 shows an enlarged longitudinal sectional view of the measuring apparatus main body 12A. Inside, a pressure sensor 123 as a water pressure measuring means on the test target area side, a flow rate sensor 122 as a flow measuring means for measuring the amount of water supplied to the test target area side, and a hole sound detecting means (not shown) at the tip side. A data recording circuit 121 is provided which records the data acquired by these means by AD conversion at regular intervals by a digital circuit incorporating a clock mechanism and records the data in a memory.

  And as a characteristic part of this measuring apparatus main body 12A, it has the cylindrical injection water chamber 124 which stored the injection water inside the base end side, and was connected with the internal space side of the boring rod 5 by the communication path 129. The open end side is sealed with the piston 125, and the water supply passage 126 extending from the distal end side of the injection water chamber 124 passes through the check valve 126 a and the flow rate sensor 122 in the inner space of the outer tube 11. It opens in the space on the tip side from the stopper 111.

  Then, due to the pressure of the high-pressure water fed through the boring rod 5 during pressurization, the measuring device main body 12A is brought into close contact with the stopper 11 in the outer tube 11, and this portion in the outer tube 11 Since the fluid flow through the pipe is sealed, only the injected water filled in the injection water chamber 124 by sliding the piston 125 due to the pressure difference passes through the water supply passage 126 and the outer tube 11 as high-pressure water, and is not shown. The water is supplied to the test target area side partitioned by the water shielding means, and the water supply path 126 is closed by the check valve 126a when the pressure is reduced.

  In addition, it is recommended to use the injected water filled in this injected water chamber 124 by adding a predetermined additive to fresh water that does not contain impurities that adversely affect various measurements and increasing the viscosity. Thereby, the influence which it has on the measurement of the water supply amount in the flow sensor 122 can be suppressed to the minimum.

  In addition, a reverse flow passage 127 that bypasses the upstream side and the downstream side of the stepped portion 120 that is locked to the stopper 111 of the measuring apparatus main body 12A is provided with a check valve 127a in the middle, and is subject to test during decompression. The in-hole water on the region side flows back to the boring rod 5 side, and the reverse flow path 127 is closed by the check valve 127a during pressurization.

  Next, the implementation procedure of the hydraulic crushing test method of this Embodiment is demonstrated. The hydraulic crushing test method in the present embodiment can also be carried out in a procedure basically similar to the procedure of the hydraulic crushing test method described in FIG. That is, the measurement is performed by partitioning the bottom of the boring hole 3B with the water-impervious means 4B and pressurizing and crushing with the high-pressure water using the space beyond that as the test target area.

  First, the outer tube 11 is connected to the tip of the boring rod 6 and inserted into the boring hole 3B (see FIGS. 1 and 3), and then suspended with a traveling tool (not shown) to measure the measurement apparatus main body (logger) 12A. Is inserted into the hole (measurement / recording is started at this point), and is inserted / placed into the outer tube 11 through the boring rod 6.

  Then, the high-pressure pump 8 on the ground side is driven, high-pressure water is sent through the inside of the boring rod 6, and high-viscosity fresh water is sent as high-pressure water from the injection water chamber 124 of the measuring apparatus main body 12 </ b> A to the hydraulic crushing chamber 32. Conduct a hydraulic fracturing test. Since the inside of the boring rod 5 is in-hole water (muddy water), a magnetic filter 130 is disposed, for example, upstream of the piston 125 to remove iron oxide impurities contained in the in-hole water by magnetic adsorption. By providing the steps, it becomes easier to remove the maximum inhibitory factor in the measurement and improve the measurement accuracy.

  Also in this hydraulic crushing test, the flow rate, pressure, and sound in the hole of high-pressure water in the portion communicating with the hydraulic crushing chamber 32 accompanying pressurization / decompression are measured and recorded. Thereafter, the measuring apparatus body 12A is collected on the ground side using a traveling tool to complete the recording, the data recorded in the data recording circuit 121 is read, and the test is terminated.

  As described above, in the present embodiment, the high-pressure water to be injected into the hydraulic crushing chamber 32, which is the test target region, is high-viscosity fresh water stored in the injection water chamber 124 instead of the muddy water in the pores. By measuring only the flow rate sent, it is possible to reliably avoid adverse effects on the measurement due to impurities contained in high-pressure water in the conventional example, and obtain highly accurate flow rate and pressure measurement results. Will be. In particular, the accuracy of extracting the flow rate change point can be improved by recording the sound in the hole.

  As described above, regarding the hydraulic crushing test carried out in the borehole, according to the present invention, it is possible to avoid a decrease in measurement accuracy due to impurities contained in the borehole water.

3A boring hole, 4A water shielding means, 5 boring rod, 8 high pressure pump, 10A measuring device, 11 outer tube, 12A measuring device main body, 30 test hole, 111 stopper, 120 step portion, 121 data recording circuit, 122 flow sensor, 123 pressure sensor, 124 injection water chamber, 125 piston, 126 water supply path, 126a, 127a check valve, 127 reverse flow path, 128 hook, 130 magnetic filter

Claims (7)

  On the distal end side of the hollow boring rod, a water blocking means for partitioning a region for injecting high pressure water in the boring hole and another region, and a measuring device having at least a water pressure measuring unit and a flow rate measuring unit are disposed, After the water shielding means is inserted up to the test target region in the boring hole to partition the test target region from the other region, the high pressure water is fed through the boring rod and the boring hole in the test target region In a hydraulic crushing test method in which pressure is applied to an inner wall and at least the fluctuation of the water pressure in the test area and the amount of high-pressure water delivered are measured by the measuring device, the injection for injecting into the measuring area in the measuring device A cylindrical filling water chamber is provided which is pre-filled with water and partitioned by a piston from the inner space side of the boring rod, and has a hole in the boring rod. Only the injected water that has been pushed out by sliding the piston due to the pressurized water is fed as the high-pressure water to the test target region side, and the amount of the injected water is measured by the flow rate measuring means. A hydraulic crushing test method characterized by recording together with the sound in the hole during crushing.   The hydraulic fracturing test method according to claim 1, further comprising a step of adsorbing and removing iron oxide impurities from water in the hole in the boring rod using a magnetic filter.   The hydraulic crushing test method according to claim 1 or 2, wherein the injected water is prepared by adding a predetermined additive to fresh water and adjusting the viscosity to a predetermined range.   The measuring device has an outer tube connected to the tip of the boring rod and the injection water chamber, and can be recovered to the ground side and inserted into and removed from the outer tube by lifting and suspending operations in the boring rod. 4. The hydraulic fracturing test method according to claim 1, 2, or 3, comprising a measuring device main body made possible.   The hydraulic crushing test method according to claim 1, 2, 3, or 4, wherein the measuring device is provided with a recording means for recording all measured data.   The hydraulic fracturing test method according to claim 5, wherein the measurement data includes recorded data of sound in the hole. A measuring device used in the hydraulic fracturing test method according to claim 1, 2, 3, 4, 5, or 6, wherein the flow rate measuring means, the hydraulic pressure measuring means, and the injection water are prefilled and the piston is used. It has at least an inner space side of the boring rod and a partitioned cylindrical injection water chamber, and the piston is slid and pushed out by pressurizing the water in the hole in the boring rod. In addition, the measurement apparatus is characterized in that only the injected water is supplied as the high-pressure water to the test target region side, and the amount of the injected water is measured by the flow rate measuring means and the underground sound is measured.

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