JPH04197888A - Riserless excavator apparatus - Google Patents

Abstract

PURPOSE:To shorten the operation time period at the time of changing the dimension of a drill pipe and reduce the weight and labour, by connecting a rise/fall ship body to a gush-preventing means of an excavation part by means of a flexible pipe, and make this pipe freely contractible and extensible by means of a pipe take-up reel. CONSTITUTION:In carrying out a sea-bottom excavating operation, after a bit 7 or gush-preventing means 8 is landed on, and installed in, a sea bottom B, seal members 21 are closed by operation of an oil pressure cylinder 22 and a drill pipe 6 is rotated by drive means to excavate the sea bottom B by the bit 7. During this excavation, an excavation muddy water is sent, through operation of an mud pump 13, into an excavation part via a muddy-water supply hose 14 and the drill pipe 6. The excavation scrap and excavation muddy water are conveyed up to a pipe take-up reel 5 via a mud-return hollow portion 19 and a flexible pipe 10 and are returned to a mud tank 12 for recovery. As the excavation depth increases, the suspension length of the drill pipe is extended. At this time, the length of the flexible pipe 10 is adjusted by delivery thereof from the pipe take-up reel 5.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a riserless drilling rig for offshore oil drilling.

[Prior art]

Generally, in a semi-submersible oil drilling rig, a drill pipe and a riser pipe are lowered concentrically from a semi-submersible floating hull (semi-submersible offshore structure), and a bit at the lower end is rotated through the drill pipe. At the same time, drilling mud is sent to the excavated part via the trill pipe, and the drilling debris and drilling mud generated during excavation are collected through the annular hollow part between the trill pipe and the riser pipe to the floating hull. After removing solids and gas, the drilling mud is circulated again through the drill pipe.

[Problem to be solved by the invention]

However, there is a strong tendency for the drilling depth in semi-submersible oil drilling rigs to gradually become deeper, for example, 3000 meters or more, and it is necessary to extend the riser pipe to correspond to the length of the drill pipe. This results in a large amount of labor during the installation and recovery of excavation equipment, and
It will be difficult to ensure the depth of space for installing and storing riser pipes in floating hulls. The present invention is intended to solve these problems, and aims to (1) omit the use of riser pipes, and (2) reduce the time required for installation and recovery of excavation equipment.

[Means to solve the problem]

In order to solve this problem, we have developed a trill pipe that is suspended on a floating ship's hull and excavates by rotating a bit at the lower end and sends drilling mud into the excavated area, a blowout preventer installed in the excavated area, and a trill pipe that excavates by rotating a bit at the lower end. It is equipped with a flexible/pull pipe that is connected to the spouting means via a connector and collects drilling debris and drilling mud produced during excavation to the floating hull, and a pipe winder that is mounted on the floating hull and winds the flexible/pull pipe. This is a riser-less drilling rig.

[Effect 1] When installing a bit in an excavated area, the drill pipes with the bits attached are connected in sequence and lowered, or the pipe take-up reel is moved in the unwinding direction at the same time as the drill pipe is being lowered. Rotate it to lower the flexible/pull pipe the length of the trill pipe. After the bit reaches the excavated part and the blowout preventer is installed, the drill pipe is rotated to perform the digging operation [1], and the drilling mud is sent into the excavated part through the drill pipe to remove the drilling debris and debris generated during excavation. Drilling mud is collected through the connector and flexible/pull pipe to the floating hull. When removing drilling equipment, the drill pipe, etc., is either lifted up gradually and recovered, or, in the case of flexible/pull pipes, the drill pipe is removed by rotating the pipe take-up reel in the opposite direction to the above-mentioned direction. This can be done by simultaneously winding up the length of the wire at the same time as lifting the wire. [Embodiment] FIGS. 1 to 4 show an embodiment of a riserless drilling apparatus according to the present invention. In each of these figures, the symbol l is a floating hull or semi-submersible marine structure), 2 is the main tenon, 3 is the trill floor, 4 is the terrestrial tank, 5 is the pipe winding reel, 6 is the trill pipe, 7 is the bit, and 8 is a blowout prevention means (blowout preventer),
9 is a connector, 10 is a flexible/pull pipe, B is a submarine,
H is the wellhead and WL is the sea level. As shown in FIGS. 1 and 2, the floating hull 1 includes a muddy water collection pipe 11 connected to the winding start end of the pipe take-up reel 5, and a muddy water collected from the muddy water collection pipe 11. a mud tank 12 for storing mud water, a mud pump 13 for transporting the mud water stored in the mud tank 12, and a mud water supply hose 14 (for transporting the drilling mud discharged from the mud pump 13 to the drill pipero). !-1 A swivel joint 15 for connecting the muddy water supply port I4 to the inside of the trill pipe, a flexible pipe tensioner 16 for suspending the flexible pipe 10, an i tensioner 16 and a flexible pipe 10. A wire lobe 17 arranged between the wire lobes 17, a sheave 18 arranged in the middle of the wire lobes 17 to adjust the tension, a driving means (path shown) for rotating the pipe take-up reel 5 in both forward and reverse directions, and rotating the trill pipero. The above-mentioned connector 9 is installed on the upper part of the blowout prevention means 8 so as to cover the well mouth H in the excavated part, and the As shown in FIG. 4, a hollow part 19 for mat return is formed in the connector 9 so that the wellhead H and the flexible pipe 10 are in communication with each other, and a drill pipe passing through the hollow part 19 is formed above the connector 9. A two-piece knoll bracket 20 for sole of the drill pipe and a 7-hole member 21 interposed between the seal bracket 20 and the drill pipe pro to obtain liquid tightness are arranged. A plurality of hydraulic cylinders 22 are disposed between the bracket 20 and the connector 9 for moving the sealing bracket 20 in a direction to clamp the sealing member 21 and fastening the sealing member 21.
A guide taper 23 is formed on the upper surface of the seal bracket 20 to guide the drill pipe to the center position when inserted. In FIG. 1, reference numeral 24 is a steady rest member that is rotatably supported around the axis of the drill pipe to prevent the flexible pull pipe IQ from shifting, and is installed at appropriate intervals in the vertical direction. Therefore, when the drill pipe, bit 7, etc. are lowered to the seabed and installed at the start of drilling, etc., the bit 7 and blowout prevention means 8 are attached to the bottom of the drill pipe, and the connector 9 is connected to the flexible This is carried out by connecting and lowering the drill pipes one after another with the pipe 10 connected, but at the same time as the work of lifting and lowering the drill pipes, the pipe take-up reel 5 is rotated in the unwinding direction, and the drill The lengths are matched by letting out and suspending the flexible pipe 1O in accordance with the length of the pipe to be suspended. The bit 7 and the blowout preventer 8 reach the seabed B, and the position of the blowout preventer 8 is set and the seal member 21 is fastened by the operation of the hydraulic cylinder 222, and the wellhead H and the hollow part I9 for mat return are closed. After isolating it from the surrounding seawater, the drill pipe is rotated by the actuation of the drive means mounted on the floating hull 1, and the drill pipe is rotated. While excavating the seabed B using the door, the mud pump 13 operates to supply drilling mud to the mud water supply hose 1.
4 and the trill pipe into the excavated area near the tip of the via door. Then, the drilling debris and drilling mud generated during excavation are transferred to the pipe take-up reel 5 of the floating hull 1 on the sea via the mat return hollow part 19 of the connector 9 and the flexible/pull pipe 10, and the mud water recovery pipe 11 to mud tank 1
In addition to collecting the waste back to step 2, the excavated debris and gas are separated. The drilling mud stored in the mud tank 12 is circulated and sent to the excavated part again. In addition, as the drilling depth increases, the length of the drill piper's suspension may be extended, or even in that case, the pipe take-up reel 5
The length is adjusted by unwinding and unwinding the flexible pipe 10. On the other hand, when removing the drilling equipment, the drill pipe and flexible pull pipe 10, etc., are gradually lifted up and recovered.As for the drill pipe, although it involves dismantling the connection part, the flexible pull pipe 10, etc. If so, the pipe can be wound and stored on the pipe take-up reel 5 by rotating the pipe take-up reel 5 in the winding direction. Therefore, in conjunction with the lifting work of the drill pipe, the flexible pipe IO is rolled up by the length of the lift of the drill pipe. In addition, as shown in FIG. 2, the flexible pull pipe 10 is provided with connection parts with the wire lobe 17 at key points, thereby reducing the tension acting on the flexible pipe IO. . [Effects of the Invention] As explained above, the riserless excavation device according to the present invention provides the following effects. (1) Since the floating hull and the blowout prevention means of the excavation part are connected by a flexible pipe, and the flexible/pull pipe is wound by a pipe take-up reel, when changing the suspension dimension of the drill pipe, The length of the flexible/pull pipe can be set by simply rotating the pipe take-up reel in forward and reverse directions, and compared to when using a conventional riser pipe,
It is possible to shorten the work time when changing the dimensions of the drill pipe, and to achieve weight reduction and labor savings. (2) By letting out the flexible pull pipe according to the depth, it is possible to easily cope with large excavation depths. (3) Compared to the case of using riser pipes in the prior art, storage space for the riser pipes is no longer required, making it possible to effectively utilize the space of the floating hull and downsize the ship.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an embodiment of a riserless drilling apparatus according to the present invention. FIG. 2 is a front view showing the flexible/pull hose winding portion in the example shown in FIG. FIG. 3 is a partially sectional front view showing the lower connecting portion of the flexible hose 7 bull hose in the example shown in FIG. 1. FIG. 4 is a view taken along line D--D in FIG. 3.

[Explanation of symbols]

1...Floating hull (semi-submersible offshore structure), 2...Main tenoki, 3...Drill floor, 4...Derrick,
5...Pipe winding sole, 6...Drill pipe, 7...Bit, 8...Blowout prevention means (Blowout 11 Henku), 9-...Furita , I
O...Flexible pipe, 11...Mud water collection pipe,
L2...Mud tack, 13-...Mud pump, 14--11 hose, 15...Suiher run yoint, 16...Tennyona for flexible/pull pipe (Tennyona), 17-... Mountain wire robe, I8...
... Nube, 19... Hollow part for mud return, 20... Bracket for hump, 21...,
cylinder member, 22-...hydraulic cylinder, 23...
Guide taper, 24--- Steady rest member, B...
- Seabed, H... Wellhead, WL... Seawater level. Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] Claims: A drill pipe that is suspended on a floating hull and performs drilling by rotating a bit at the lower end and sends drilling mud into the excavated part, a blowout preventer installed in the excavated part, and a connector to the blowout preventer. A riserless system characterized by comprising: a flexible pipe that is connected to the floating hull and collects drilling debris and drilling mud generated during excavation to the floating hull; and a pipe take-up reel that is mounted on the floating hull and winds the flexible pipe. drilling rig.