JPH0447119B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydraulic fracturing of submarine rock.

When dredging hard ground for port construction etc.
The seabed ground must be crushed in advance, and methods of crushing include blasting and heavy rock crushing.

The blasting method is a construction method that uses the expansion pressure generated by rapid chemical changes in gunpowder to blast rocks, etc. The blasting method involves drilling holes in underwater rock, charging it, and detonating it.

The heavy rock crushing method is installed on a rock crushing ship with a weight of 10 tons or more.
A 30-ton steel rod is dropped vertically at a certain point, and the rock at that point is successively crushed by the impact.

However, the blasting method cannot avoid large vibrations and impact pressure, and the heavy rock crushing method has problems such as loss of impact energy and low work efficiency on sloping ground.

On the other hand, hydraulic fracturing is a method of crushing rock while minimizing the shock and vibration inherent in rock crushing methods, such as in blasting methods.

Hydraulic fracturing is a construction method that uses high-pressure jet water to destroy rocks or bedrock, and one of its advantages is that it produces less shock and vibration.

However, in order to use this construction method on underwater rock such as submarine rock, several problems must be solved.

For example, even if a hole is drilled in the bedrock using a hydraulic fracturing method and an expansion pressure fracture is performed, it may be difficult to install a packer in the fracture hole, or the drilling itself may be difficult.

An object of the present invention is to provide a method for hydraulic fracturing of seabed rock, which can suppress shock and vibration by using the hydraulic fracturing method for fracturing seabed rock, and which also has good work efficiency.

That is, the present invention relates to a method for hydraulic fracturing of seabed rock, which is carried out by discharging a large amount of high-pressure water from the tip of a high-pressure water supply path into a hole drilled in seabed rock for a short period of time.

Next, embodiments of the present invention will be described with reference to the drawings, but first, an apparatus used in the method of hydraulic fracturing of submarine rock according to the present invention will be described.

The device used in the present invention is composed of a crushing device main body A, a pedestal B supporting the crushing device main body A, a holder portion D, and a support column C. (Fig. 1) (a) Main body of the crushing device (Fig. 2) As shown in Fig. 2, the main body A of the crushing device has a double-tube structure. It consists of an outer tube 2 which is short and has an inner diameter larger than the outer diameter of the inner tube 1.

The space between the two pipes is used as a high-pressure water supply path 3.

[Inner tube] The inner tube 1 is a small diameter cylinder with a nozzle 11 installed at its open end, and an ultra-high pressure swivel 12 at its base end.
and a motor section 13 that rotates the inner tube 1.

The nozzle 11 is a cylinder with a conical bottom, and has a tip 20 and a plurality of orifices 14 at the bottom, and a plurality of horizontal orifices 15 in the cylinder in a direction perpendicular to the axis.

The ultra-high pressure swivel 12 is a swivel with a known structure, and connects the ultra-high pressure water supply device E to the ultra-high pressure pipe 17.
The structure is such that ultra-high pressure water is sent into the rotating inner tube 1 through the inner tube 1.

Also, joints 19 are provided at several locations in the ultra-high pressure pipe 17 so that the ultra-high pressure pipe 17 can bend in any direction.

The ultra-high pressure swivel 12 allows the inner tube 1 to rotate using a gasket, support, etc. in the same way as the conventional one, and is fixed to the inner tube 1 in a brim shape to prevent water leakage.

The motor section 13 is a member of a known mechanism that rotates the inner tube 1 using hydraulic pressure or compressed air from the drive section F.

Hydraulic pressure or compressed air is then fed in via hose 18.

Further, the inner tube 1 can be connected at its intermediate portions by means of a coupling ring 16 depending on the length of the perforation.

[Outer tube] (Fig. 2) The outer tube 2 is connected to a casing bit 22 having a metal tip 21 installed on the nozzle 11 side of the inner tube 1, and a high pressure swivel 23 is connected to the other end.

The high-pressure swivel 23 instantly supplies a large amount of high-pressure water from the high-pressure water supply device H via the supply hose 24 and the accumulator G to the casing bit 22 through the high-pressure water supply path 3 between the inner pipe 1 and the outer pipe 2. It is a member to be supplied.

The high-pressure water supply path 3 is located on the outer periphery of the inner tube 1, has a cross-sectional area larger than the cross-sectional area of the inner tube 1, and can supply a large amount of water.

It is also conceivable that the supply hose 24 may be used to supply low-pressure water for slime discharge during drilling.

The high-pressure swivel 23 is installed across the upper end of the inner tube 1 and outer tube 2 exposed from the upper part of the outer tube 2, and similarly to the ultra-high pressure swivel 12, the inner tube 1 and the outer tube 2 are Install it in such a way that it can be rotated and that there is no water leakage.

Further, the outer tube 2 and the inner tube 1 are connected by a connecting portion 25 so that the rotation of the inner tube 1 by the motor portion 13 is transmitted to the outer tube 2.

The outer tube 2 is also constructed so that an extension tube can be connected to the intermediate portion thereof depending on the length of the hole to be drilled.

(b) Frame and strut (Fig. 1) Frame B and strut C are members that support the crusher main body A.

The crushing device main body A passes through a holder portion D of the pedestal B, and the support column C supports the crushing device main body A perpendicularly to the pedestal B.

In addition, the holder part D is attached to the crushing device main body A by hydraulic pressure.
Tighten and secure it to pedestal B.

For example, a hook or the like is attached to the top of the column C so that the device can be hung by a crane or the like.

Further, an inclination angle detector is placed on the pedestal B, and a known leveling mechanism is provided to maintain the required posture. (None of these are shown) Next, a method for crushing submarine rock using the above-mentioned device will be described.

(b) Sedimentation The equipment is hoisted by a crane, etc., and settled on the designated sea floor.

(b) Drilling (Figures 2 and 3) For example, 3000Kg/
Ultra-high pressure water of about cm ² is passed through the ultra-high pressure pipe 17 and the ultra-high pressure swivel 12 to the nozzle 11 at the tip of the inner pipe 1.
send to

At the same time, the motor section 13 operates and rotates both the inner tube 1 and the outer tube 2, and the orifice 14 of the nozzle 11
Drilling into a predetermined rock mass is started using the ultra-high pressure water discharged from the horizontal orifice 15 and the tip 20 at the tip of the nozzle 11.

At this time, the ultra-high pressure water from the horizontal orifice 15 expands the diameter of the hole, and the crushing device main body A enters the crushing hole 5.

Since the inner tube 1 has a small diameter, it can discharge extremely high-pressure water that can cut through rocks in a thread-like state, although the flow rate is small.

If the slime is not being discharged smoothly during drilling, low-pressure water may be supplied from between the inner tube 1 and the outer tube 2 through the supply hose 24 to facilitate slime discharge.

(c) Hydraulic fracturing (Fig. 4) When the predetermined drilling length is obtained, hydraulic pressure is applied to the holder portion D of the pedestal B to fix the crushing device main body A to the pedestal B.

After fixing the crusher body A to the pedestal B, it was stored under pressure in the accumulator G.
For example, high pressure water of about 300 kg/cm ² is introduced through the supply hose 24.

Since the high-pressure water supply path 3 is located on the outer periphery of the inner pipe 1, it has a large cross-sectional area. Therefore, at the bottom of the fracture hole drilled in the rock, high-pressure water flows toward the surrounding hole wall, albeit for a very short time. can be discharged in large quantities.

At this time, the diameter of the crushing hole drilled in the rock and the outer diameter of the outer tube 2 are approximately equal, and only a small gap is created between the crushing hole and the outer tube 2.

Therefore, a large amount of high-pressure water instantly discharged into the fracture hole through the high-pressure water supply path 3 has no place to escape, and most of the water pressure acts on the surrounding rock as an excessive tensile force.

Therefore, rock can be efficiently crushed.

At this time, since the crushing device main body A is fixed to the rack No. B, the weight of the device itself prevents the crushing device main body A from floating due to the reaction force during hydraulic fracturing.

(d) Drilling arrangement Repeat the above operations to crush the rock in the specified range.

When drilling holes, the fracture area 5 from each fracture hole 5
Drill the holes so that 1 overlaps.

In addition, if the bedrock has a slight inclination, the inclination angle detector on rack B and the leveling mechanism are used to adjust the required posture.

(E) Other Examples 1 After drilling or simultaneously with drilling, one or more cuts along the drilling direction or disc-shaped cuts in a direction perpendicular to the drilling direction may be made in the vicinity of the hole. It is also possible to control the crushing direction, crushing shape, crushing size, etc.

(f) Other Example 2 In this example, for convenience, the inner pipe is used as the supply route for ultra-high pressure water for excavation, and the outer pipe is used to create the supply route for high-pressure water for rock crushing between the inner pipe and the inner pipe. However,
It is also possible to replace each supply source and use the inner pipe for high-pressure water for rock crushing, and use the space between the outer pipe and the inner pipe as an ultra-high-pressure water supply path for excavation.

(G) Other Embodiments 3 In this embodiment, a drilling method was used in which holes were drilled using ultra-high pressure water, but it is also possible to use a commonly used pneumatic drill or hydraulic drill.

In this case, a supply path is provided to send high-pressure water from the high-pressure water supply device into the borehole without passing through the accumulator, and high-pressure water is supplied to treat slime during excavation, and the water is accumulated in the accumulator after drilling is completed. The system is designed to instantly send high-pressure water to crush rock.

Since the present invention is as explained above, the following effects can be obtained.

(b) Since the hydraulic fracturing method is used, there is low vibration and low impact.

(b) Since the crushing is performed using the own weight of the device itself as a reaction force, there is no need to install other devices or tools such as a patrol car.

(c) Since the equipment is lifted and operated by a crane, it is easy to move and the crushing work can be carried out continuously, making it efficient and economical.

(d) As a conventional technique, there is a technique in which the tip of the high-pressure water supply channel is located outside the fracture hole and a mass of fluid is discharged into the fracture hole. However, in this case, the tip of the high-pressure water supply channel Since there is a distance between the hole and the opening of the crushing hole, all the openings of the crushing hole are open.

Therefore, the high pressure water discharged into the fracture hole is
It becomes very easy to escape to the outside of the fracture hole.

Therefore, the tensile force caused by the water pressure of the high-pressure water does not act much on the surrounding rock, making it difficult to efficiently crush the rock by the tensile force.

In contrast, in the present invention, an inner tube and an outer tube are inserted into the crushing hole.

After insertion, high-pressure water is discharged at the bottom of the crushing hole toward the surrounding hole wall.

The diameter of the crushing hole and the diameter of the outer tube are approximately equal, and only a small gap is created between the crushing hole and the outer tube.

Therefore, there is no place for the large amount of high-pressure water that is ejected in an instant to escape, and most of the water pressure acts on the surrounding rock as a tensile force.

Therefore, rock can be efficiently crushed.

(E) The present invention uses an integrated structure of a crushing device based on the above-mentioned principle and a drilling device for drilling into rock.

Therefore, the crushing device can be inserted simultaneously while drilling into the rock, and the rock can be continuously crushed immediately after drilling is completed.

Therefore, working time can be shortened and working efficiency can be improved.

(f) The drilling performance is affected not by the discharge amount of high-pressure water but by the injection speed, and the crushing range is not affected by the jetting speed of high-pressure water but by the pressure, that is, by the injection amount of high-pressure water.

Therefore, by making the high-pressure water supply channels separate and independent, high-pressure water can be supplied under optimal conditions according to each purpose, so that the drilling performance and crushing performance are significantly improved.

(g) As a conventional rock crushing technology,
There is a technique disclosed in Publication No. 63101.

This crushing technology is carried out in a blind hole drilled into the rock.
A supply pipe that supplies a fixed amount of high-pressure water is inserted, and the fixed amount of water is accelerated into this blind hole and collides with it to fracture the rock.

However, this conventional crushing technology cannot perform continuous crushing and has low crushing performance because it uses the impact destructive force of water to crush rock.

In contrast, in the present invention, the drilling process using an ultra-high pressure water jet and the crushing process performed by injecting a large amount of high-pressure water in a short time can be performed repeatedly and continuously, so the crushing performance of the submarine rock is improved compared to the conventional method. is significantly improved.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of the entire device, Figure 2: A sectional view of the crushing equipment main body, Figure 3: An explanatory diagram of the hole drilling method,
Figure 4: Explanatory diagram of crushing method 1: Inner pipe, 2: Outer pipe, 3: High pressure water supply path, 5:
Crushing hole, 12: Ultra high pressure swivel, 13: Motor part, 23: High pressure swivel, 51: Crushing area, A:
Crushing device main body, B: Frame, C: Support column, D: Holder section, E: Ultra-high pressure water supply device, F: Drive section, G:
Accumulator, H: High pressure water supply device.

Claims (1)

[Scope of Claims] 1. Consisting of an inner tube having a flow path on its axis, and an outer tube with open ends at both ends that accommodates this inner tube, and an injection hole communicating with the flow path of the inner tube at the tip of the inner metal tube. The flow path of the inner tube of the double tube structure and the space formed between the circumferential surfaces of both tubes are used as independent high-pressure water supply paths for drilling and high-pressure water supply paths for crushing, respectively. A process of drilling a hole in seabed rock by injecting high-pressure water supplied through a high-pressure water supply line for drilling onto the seabed ground using a crushing device, and a process in which a large amount of high-pressure water supplied through a high-pressure water supply line for crushing is used to drill a hole in the seabed. A method of hydraulic fracturing of submarine rock that involves repeating the process of injecting water into a hole.