JPH0472033B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is applicable to deep borehole drilling such as geothermal power generation drilling, oil drilling, mineral resource drilling, and various resource exploration drilling, in which circulating mud for drilling is removed from the hole wall. This article relates to a water stoppage method for deep boreholes that prevents water from escaping.

"Prior art" The state of deep boring is as shown in Figure 2, where 1 is the casing and 2 is the casing 1.
With a drill rod that penetrates through the drill rod, circulating mud for drilling is injected into the bottom of the hole from the tip through the hollow core of the drill rod 2, filling the hole 3, and being collected in a tank 4 on the ground. Note that arrow 5 in the figure indicates lost water.

Conventional water stoppage construction methods include those listed below.

Method by adjusting the concentration of muddy water This method is a construction method that seals the diversion layer (cracks) by increasing the concentration of muddy water.

Method using cement grout This method involves pouring cement grout alone or cement grout mixed with wood chips, straw, etc. into a deep borehole to prevent water loss.

Method of injecting chemical liquid through a hose This method is a construction method in which a water stop chemical liquid that gels in water is injected through an injection hose lowered to a predetermined depth (water leakage point).

Method of injecting chemical liquid through a rod This method is a construction method in which a water-stopping chemical liquid that gels in water is injected using a lowered injection rod while adding water to a predetermined depth (water loss area).

Method for injecting water-stopping chemicals using capsules In this method, a water-stopping chemical solution is set in a capsule at a predetermined gel time and is lowered to a predetermined depth (water loss layer), and the capsule is ruptured to stop water.

``Problems to be solved by the invention'' However, the conventional construction methods described above have the following problems.

In other words, the above-mentioned method is advantageous because it allows the drilling rod to remain in place, but since the mud particles are not as large as gelled materials, it is not effective when the crack width is large or water loss is severe. .
Moreover, if the concentration becomes too high, it has the disadvantage of collapsing the weak pore walls other than the water loss area (because it adheres only to the surface of the pore wall without penetrating into the wall).

This method is advantageous because it allows the drilling rod to remain in place, but it takes a long time for the cement to harden (8 to 10 hours), so it takes time to stop water, and it also causes water to stick to the surface of the hole wall. It is difficult to penetrate, and the series of excavation systems will stop for 2 to 3 days or even several tens of days if there is severe water leakage.In addition, circulating mud water is wasted and tens of tons of cement are used. Furthermore, cement has poor permeability, so re-excavation will cause the hole wall to collapse.

The methods of ~ have a common drawback that it takes time to raise and lower the excavating rod (5 to 10 hours depending on the depth) because the excavating rod must be raised. If it is not pulled up, using a strong chemical solution may cause the drilling rod to stop moving, so this is an advantage. If this happens, there will be a loss of chemical solution (inside the hose). With this method, it takes time to lower the injection rod, and due to the rod's strength, it can only be done for a distance of about 700 meters, resulting in a loss of chemical solution. Furthermore, it takes time to lower the drilling rod after raising the injection rod.
This construction method has the inconvenience of not being able to descend to a predetermined depth and destroy the capsule reliably and safely, and not being able to continuously supply up to a predetermined amount, making it incapable of dealing with large water leaks. Furthermore, there are cases where the capsule cannot descend smoothly.

``Means for Solving Problems'' and ``Operations'' The present invention was made in view of the above circumstances, and its gist is to interrupt the circulation of muddy water in the drilling rod when water leakage occurs. Then, pull up the drilling rod, remove the tricombit at the tip, lower it, insert an injection hose with a spray nozzle that also serves as injection into the tip of the drilling rod, and lower it, and use the injection hose to stop water. Grout consisting mainly of chemical liquid was discharged into the drain area, and after the water stopped, the injection hose and drilling rod were pulled up, the tricone bit was reattached to the drilling rod, and re-excavation was started. The object of the present invention is to provide a suitable new construction method that uses a drilling rod as a guide to reliably and quickly inject a chemical solution.

"Example" This will be explained in detail below based on the figures.

FIGS. 1a to 1f are explanatory diagrams of the procedure of the construction method of the present invention. Due to the occurrence of lost water, the circulation of muddy water is interrupted and the drilling rod 2 is pulled up (Figure a).

Remove the tricone bit 2a at the tip of the excavation rod 2, open the tip of the rod 2, and lower it (Figure b). In reality, the tip opening should be located about 50m above the water loss point.

An injection hose 6 having an injection nozzle 6a for injection at its tip is inserted into the excavation rod 2 and lowered (Fig. c). A grout containing a water-stopping chemical as a main component is discharged through the injection hose 6 towards the water leakage area,
It goes behind and sends muddy water to stop the water (Figure d).

Incidentally, in order to supplement water stoppage, cement milk may be sent later from the drilling rod 2 instead of muddy water.

After the water has stopped, pull up the injection hose 6 and then the excavation rod 2 (Figure e).

Reinstall the tricone bit 2a and install the drilling rod 2.
was lowered and re-excavation began (Figure f).

However, when the drilling rod was pulled up, it was to remove the tricone bit in order to open the tip, and the drilling rod was used as a guide to lower the rod without moving the installation base, and the tricone bit was pulled up in the same way even after the water had stopped. Since the device is reattached and lowered, it can be operated quickly and the chemical solution can be supplied most reliably.

"Effects of the Invention" The effects of the present invention are listed below.

(1) The injection hose can be inserted into the drilling rod, allowing for smooth descent.

(2) Since it is an injection hose, there is no time lost for adding pipes.

(3) Water can be reliably injected and stopped at areas where water is lost.

(4) Gel time and injection amount can be adjusted according to the water loss situation, so there is no wastage of chemical solution.

(5) Since the injection hose is inserted into the drilling rod, the chemical solution does not adhere to the inner wall of the drilling rod.

(6) Since muddy water and cement milk can be sent from the drilling rod while discharging chemical liquid from the injection hose, it functions as a pressurer from above and has the effect of pushing the discharged chemical liquid into the fixer.

[Brief explanation of the drawing]

Figures 1 a to f are explanatory diagrams of the procedure of the method of the present invention, and Figure 2
The figure is an explanatory diagram of the water loss situation. 1...Casing, 2...Drill rod, 2a
...tricone bit, 3...hole, 4...tank,
5... Lost water, 6... Injection hose, 6a... Injection nozzle.

Claims (1)

[Claims] 1 When water leakage occurred, the circulation of mud in the drilling rod was interrupted, the drilling rod was lifted up, the tricone bit at the tip was removed, and then lowered, and an injection nozzle was attached to the tip of the drilling rod for both injection and injection purposes. Insert and lower the injection hose, discharge the water stop chemical solution to the water leakage area through the injection hose, and after stopping the water, pull up the injection hose and drilling rod, reinstall the tricomb bit on the drilling rod, and start digging again. A water stop method for deep boreholes, which is characterized by the following: