JPS6312235Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a subseafloor cementing device used when installing a wellhead device below the seabed.

Wellhead equipment for offshore oil production, secondary offshore oil production,
Conventionally, the cementing equipment shown in Figures 1 and 2 has been used to bury housing and casing pipes used when installing wellhead equipment such as wellhead equipment for injecting chemicals for tertiary recovery on the seabed. It is used.

That is, a permanent guide base 3 equipped with a cylindrical casing pipe 2 is installed in a ring-shaped temporary guide base 1 installed on the seabed surface 16 via a gimbal 4 made of a spherical rib, and the casing Pipe 2 is cement 5
A well 6 is drilled below the casing pipe 2. A running tool 8 is attached to the lower end of the digging pipe 7 that is lowered from a drilling ship at sea, and the running tool 8 is attached to a housing 10 on which a casing pipe 9 is suspended.
It is removably installed by remote control.
A cementing shoe 12 having a check valve 11 is attached to the lower end of the casing pipe 9. Using the cementing shoe 12 as a guide, the casing pipe 9 is suspended by the excavation pipe 7 and the running tool 8, so that the casing pipe 9 is suspended from the excavation pipe 7 and the running tool 8. The housing 10 is inserted into the well 6 and fixed by a connecting mechanism 13 at a position where the housing 10 is seated on the permanent guide base 3.

Furthermore, a digging pipe 14 that reaches into or near the cementing shoe 12 is connected to the lower side of the running tool 8.

Cement milk made from cement and water injected into the digging pipe 7 from the drilling ship is pumped through the drilling pipe 7, the running tool 8, and the drilling pipe 14, and is squirted out from the tip of the drilling pipe 14 to reach the check valve. 11 into the well 6, and is further filled into the well 6 while pushing up the muddy water for drilling inside the well 6. At this time, the muddy water passes through the slot 15 provided on the outer circumferential surface of the housing 10 and is discharged into the sea near the seabed 16, and even after the cement milk is filled into the well 6, the cement milk flows from the ocean. Once fed, the cement milk overflows from the slot 15 into the sea, a portion of which is diffused into the sea, and a portion of which is deposited near the slot 15.

When the supply of cement milk is stopped, the float ball 17 of the check valve 11, which had been lowered, floats up to prevent the cement milk from flowing back. Thereafter, the running tool 8 is unlocked from the housing 10 by remote control, and the drilling pipe 7, running tool 8, and drilling pipe 14 are pulled up as a unit. When the lower end of the drilling pipe 14 rises to just above the housing 10, the water is removed from the drilling ship. The cement deposits on the housing 10 and the permanent guide base 3 are washed away by jetting.

However, if the wellhead device is installed in the buried housing 10 and casing pipe 9 using this device, the wellhead device will protrude above the seabed surface 16, which may cause accidents in icy areas and areas where bottom trawl fishing is active. Become.

Therefore, it is preferable to install the wellhead device below the seabed surface, but with the conventional cementing device described above, it is difficult to install the housing 10 below the seabed surface 16, and even if it were attempted, it would be difficult to install the housing 10 below the seabed surface 16. Since it is not easy to remove the cement milk that overflows and accumulates on the housing installed in the housing, it is not possible to avoid problems caused by cement hardening and adhesion.

The present invention was developed with the aim of eliminating the drawbacks of the conventional cementing equipment described above. After drilling a well below the caisson installed under the seabed, a casing pipe is inserted, and the upper end of the casing pipe is The housing part is supported in the middle of the caisson, and when cement milk is injected into the outer space of the casing pipe, the overflowing cement milk is collected at the outer circumference of the housing, guided into the pipe line, and discharged into the sea. This is a subseafloor cementing device that prevents cement milk from accumulating inside the wellhead and enables the wellhead device to be buried below the seabed.

Embodiments of the present invention will be described below based on the drawings.

A ring-shaped temporary guide base 1 is provided at a predetermined position on the seabed surface 16, and a cylindrical caisson is suspended below the ring-shaped permanent guide base 3 in a hole 18 provided below the temporary guide base 1. 19 is inserted, and the caisson 19 is fixed to the seabed with cement 5. The caisson 1
A stepped portion 20 is provided in a ring shape in a protruding manner on the inner peripheral side of the middle portion of the shoulder 9, and a shoulder 21 is provided in a ring shape in a protruding manner at the lower part of the stepped portion 20.

A cylindrical casing pipe 9 is suspended from the lower part of a housing 10 having a slot 15 on the outer periphery.
A float ball 1 is attached to the lower end of the casing pipe 9.
Cementing shoe 1 with 7 type check valve 11
2 is installed.

A running tool 8 that can be attached to and detached from the housing 10 by remote control is attached to the lower end of a digging pipe 7 that is suspended and lowered by a traveling hook block 24 of a drilling tower 23 of a floating body 22 such as a drilling ship. A well 6 fitted with the housing 10 and drilled below the caisson 19
Then, the casing pipe 9 suspended in the housing 10 is inserted using the cementing shoe 12 at the tip as a guide, and the ring-shaped bracket part 25 on the outer periphery of the housing 10 is seated on the shoulder 21 on the inner periphery of the caisson 19. Bracket part 2
5 and the stepped portion 20 are locked by a connecting mechanism 26. A digging pipe 14 that reaches the cementing shoe 12 at the tip of the casing pipe 9 is connected to the lower part of the running tool 8 so as to communicate with the digging pipe 7.

Further, a ring-shaped sealing mechanism 27 is provided directly above the bracket part 25 of the housing 10 inserted into the stepped part 20 of the caisson 19, and sealing mechanism 27 is connected to the stepped part 20 using gaskets 28 and 29 such as rings. 27 and between the seal mechanism 27 and the outer periphery of the housing 10, one or more flow passages 30 are provided inside the seal mechanism 27 in the vertical direction, and an upper opening of each flow passage 30 is provided. One end of each pipe is directly connected, and the other end of each pipe is extended to above the permanent guide base 3.
The dump line 31 is formed by bending at a right angle at a place sufficiently higher than the above. The dump line 31 is connected to the outer periphery of the running tool 8 by a connecting mechanism 32, and the dump line 31 and the seal mechanism 27 are integrally supported.

In the figure, 33 is a tapered part, 34 is a cement powder tank, 35 is a water tank, 36 is a cement and water mixing mechanism, 37 is a pump for feeding cement milk, 38 is a flexible hose, and 39 is a rotary swivel. .

After drilling a well 6 below the caisson 19, a dump line 31 was connected to the running tool 8 and the flow path 30 to the housing 10 on which the casing pipe 9 having the cementing shaft 12 at the tip was suspended on the floating body 22. The sealing mechanism 27 is attached, the dump line 31 is supported by the running tool 8 by the connecting mechanism 32, and the running tool 8 is lowered by the traveling hook block 24 while adding the digging pipe 7 for suspending it. The pipe 9 and the housing 10 are sequentially inserted into the caisson 19 suspended from the permanent guide base 3, and the sealing mechanism 2 is attached to the outer periphery of the housing 10.
The lower end of the caisson 19 is guided by the tapered part 33 of the inner stepped part 20, so that the axial center of the caisson 19 and the center of the seal mechanism 27 coincide. Furthermore, when the housing 10 is lowered, the packing 28 attached to the outer circumferential surface of the sealing mechanism 27 is compressed by the inner circumferential surface of the stepped part 20 and becomes a sealing state, and the ring-shaped bracket provided on the outer circumference of the housing 10 is closed. The portion 25 is supported by a shoulder 21 projecting from the stepped portion 20, and at the same time, the housing 10 and the caisson 19 are connected by a connecting mechanism 26. As a result, a seal is established between the outer circumferential surface of the housing 10 and the inner circumferential surface of the stepped portion 20 of the caisson 19 via the ring-shaped sealing mechanism 27 and the packings 29 and 28 provided on the inner and outer circumferences of the ring-shaped sealing mechanism 27.

Next, cement is sent from the cement powder tank 34 and water from the water tank 35 at an appropriate ratio, mixed by the mixing mechanism 36 to form cement milk, and pressurized by the pump 37 to transfer the cement milk to the flexible hose 38 and the rotary swivel. 3
9. When the cement milk is sequentially fed to the digging pipe 7, running tool 8, and drilling pipe 14, the cement milk squirted from the tip of the drilling pipe 14 pushes down the float ball 17 of the check valve 11 and flows out of the cementing shoe 12. It is pushed out and fills the well 6 while pushing up the drilling mud inside the well 6. Further, the cement milk that has passed through the slot 15 in the ring-shaped bracket part 25 enters the dump line 31 through the flow path 30 in the seal mechanism 27, and is then transferred to the dump line 31.
It overflows into the sea outside the permanent guide base 3 through the opening of the first bent portion 40 .

After the cement injection is completed, the running tool 8 is unlocked by remote control from the housing 10 and pulled up together with the digging pipe 7, and the dump line supported by the connecting mechanism 32 on the digging pipe 14 on the lower side of the running tool 8 and the outer periphery of the running tool 8 is removed. 31, the seal mechanism 27 is pulled up onto the floating body 22. At this time, the float ball 17 of the check valve 11 of the cementing shoe 12 rises when the supply of cement milk is stopped, and the cement milk filled in the well 6 is prevented from flowing back.

As a result, the housing 10 and the tapered portion 33
It becomes possible to inject cement milk into the caisson 19 without depositing it in the upper caisson 19.

Furthermore, in the post-process, a wellhead device is installed inside the caisson 19 above the housing 10.
Since cement is not deposited above the tapered portion 33 on the outer surface of the housing 10, on the inner circumferential surface of the housing 10, and on the inner circumferential surface of the casing pipe 9, subsequent work can be carried out smoothly.

The sub-seafloor cementing device of the present invention is not limited to the above-described embodiments, and the number of slots provided in the ring-shaped bracket on the outer periphery of the housing and the number of flow passages provided in the sealing mechanism may be one or more. If you use a dump line connected to the flow path of the seal mechanism that reaches a sufficiently high point above the seabed surface, the cement milk will diffuse into the seawater and will not settle into the caisson, so the bend can be omitted. Of course, various modifications can be made without departing from the gist of the present invention, such as that the present invention can be used for cementing not only on the seabed but also under the lakebed.

As described above, according to the subseafloor cementing device of the present invention, (i) After drilling a well downward through the inside of a caisson buried under the seabed, a casing pipe with a diameter smaller than the inner diameter of the caisson is inserted; However, after supporting the casing pipe inside the caisson under the seabed, when injecting cement into the annulus,
Drilling mud, a mixture of mud and cement, cement milk, etc. rising from the well are guided into the dump line by the cement seal mechanism and discharged into the seawater above the seabed.
Prevents cement milk from accumulating inside the caisson.

(ii) Since it is possible to prevent cement milk from accumulating inside the caisson, there is no need to clean the cement milk inside the caisson after cement is placed. That is,
In the case of deep water, if the cement washing device is lowered into the caisson again after cementing and the cement is washed, the cement hardens during the setup and is likely to become impossible to clean. Since intrusion can be prevented, troubles caused by hardening and adhesion of cement can be avoided.

(iii) Since the inner surface of the caisson under the seabed can be reliably maintained clean, it becomes reliable and easy to insert and install the wellhead device inside the caisson in the subsequent process.

(iv) These (i) to (iii) make it possible to install buried type wellhead equipment, and it is possible to install buried type wellhead equipment for offshore oil production or secondary and tertiary recovery in ice areas and sea areas where bottom trawl fishing is active. Installation problems can be solved.

etc., exhibits various excellent effects.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional cementing device.
FIG. 2 is a view taken along the - direction arrow in FIG. 1, and FIG. 3 is an explanatory diagram of the sub-seafloor cementing apparatus of the present invention. In the figure, 3 is a permanent guide base, 6 is a wellbore, 7 and 14 are drilling pipes, 8 is a running tool, 1
0 is housing, 12 is cementing shoe, 1
9 is a caisson, 20 is a stepped part, 21 is a shoulder, 25 is a bracket part, 27 is a seal mechanism, 3
0 is a flow path, 31 is a dump line, and 33 is a tapered portion.

Claims (1)

[Scope of utility model registration request] A vertically communicating flow path is provided between a casing pipe that is suspended via a running tool and a housing by a digging pipe, and a cylindrical caisson that is buried in the seabed into which the casing pipe is inserted. A ring-shaped sealing mechanism having at least two locations is provided, a hollow pipe is connected to the upper outlet of the flow path, one opening of which reaches into the sea above the seabed surface, and a digging pipe and a running tool for suspending the housing are provided. A sub-seafloor cementing device, characterized in that the cement milk supplied to the outside of the casing pipe suspended in the housing can be dissipated into the sea by the hollow pipe.