NL1017967C2 - Cleaning installation for cleaning very long pipes. - Google Patents

Description

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Cleaning installation for cleaning very long pipes.

Device for cleaning pipes of the coiled tubing type as used in boreholes for oil or gas, where lengths of hundreds of meters occur. The pipes must be cleaned of deposits, possibly radioactive, before they are wound on large drums.

Coiled tubing is a tube that is made from a strip of carbon steel that is formed into a tube and welded along its length. The tube is wound in large lengths (up to 6000 meters) on a drum.

io It is known to clean objects using high-pressure water. In general, a spray lance is used to spray water with a pressure of more than 100 atmospheres on the object to be cleaned.

Cleaning coiled tubing pipes used in boreholes for oil or gas is difficult because the pipe diameter is relatively small and the fact that these pipes are hundreds of meters long. These pipes are often contaminated with light radioactive material. It has now been found that pipes cleaned in the traditional manner become radioactive again after some time. Research has shown that the pipes on the surface have micro-cracks in which dirt was left behind after cleaning.

The invention relates to a device which intensively cleans the pipes and which can be arranged around the pipe in the vicinity of the borehole.

The device consists of a cabinet which is divided over the length in which adjustable guide rollers guide the pipe through a divided spray plate. The spray plate is provided with a number of nozzles which are connected to a high pressure water pump. The cabinet has a connection with a vacuum pump.

The nozzles in the spray plate are angled in order to achieve good cleaning. During the process, the cabinet is pressurized with a large capacity pump. The halves of the cabinet fit together without specific sealing.

The invention is discussed with reference to the drawing.

FIG. 1 shows a longitudinal section through the cabinet.

FIG. 2 shows a section through the guide rollers.

FIG. 3 shows a section through the divided spray plate.

In Fig. 1 (1) is the coiled tubing to be cleaned. Coiled tubing (1) is guided by double conical guide rollers (2) which can be adjusted with the adjusting mechanism (3) to the diameter of coiled tubing. Half plastic rings (6) are provided in the side wall (4) of the cabinet (5). Case (5) is divided in two along its length and connected to each other with hinges (7). Opposite hinges (7) are arranged closures (not shown). At (8) a vacuum connection is provided for a vacuum pump with a large capacity.

A divided spray plate (9) is arranged in the middle of the cabinet (5) in which there are nozzles (10) with nozzles (11) which give a flat spray pattern. The number of nozzles (10) is 05 depending on the maximum diameter of the coiled tubing to be cleaned. The nozzles are connected with channels (12) to the high pressure water connection (13).

The center line of nozzles (10) in spray plate (9) is at an angle (14) between 85 and 65 degrees with respect to the center line of coiled tubing (1).

Case (5) is not provided with a special seal on the partial surfaces. Neither are there any special seals at the adjusting mechanism (3). The plastic half-rings (6) have a wide fit around coiled tubing (1). The leakage through the cracks in combination with the vacuum causes a mime ventilation in the cabinet (5).

The device is used when a coiled tubing is pulled out of a borehole and rolled up on a drum. The device is portable and can be arranged around coiled tubing (1) in the open position. After the device has been closed, the vacuum pump and the high-pressure water pipes are connected. The water pressure is between 1800 and 3300 bar and the vacuum is kept at less than 0.1 bar absolute. The temperature of the liquid is between 80 and 100 degrees Celsius when the jet hits the coiled tubing (1). A sensor is present in the device which measures and signals the underpressure when it exceeds 0.1 bar absolute and the cleaning operation is stopped. There is a device in the device that signals when coiled tubing (1) comes to a halt.

The device is placed as close as possible above the borehole and put into operation while coiled tubing (1) is wound on a drum.

It has been found that the combination of vacuum and spraying at an angle of preferably 75 degrees with respect to the center line of coiled tubing (1) and a temperature between 80 and 100 degrees Celsius with a constant leakage along the partial surfaces and half rings ( 6) has a particularly good effect whereby almost all radioactive contamination has disappeared.

Between the device and the vacuum pump is a water separator that collects water and dirt. In some cases it is possible to use part of the collected water after separation for the high-pressure pump.

1017S87

Claims (7)

Device for the external cleaning and decontamination of pipes of the coiled tubing type using pressurized liquid, characterized in that the coiled tubing (1) to be cleaned is guided through a divisible cabinet (5) in which a divided spray plate (5) 9) with nozzles for liquid which are directed at an angle (14) to the exterior of the coiled tubing (1) to be cleaned and in which there is an underpressure in the cabinet (5) of less than 0.1 bar absolute and the liquid is supplied under a pressure of 1800 to 3300 bar. io Device for external cleaning of pipes according to claim 1, characterized in that the cabinet (5) is provided with adjustable double-conical guide wheels (2). Device for external cleaning of pipes according to claims 1 and 2, characterized in that the closing surfaces of the cabinet (5) have no seal and the half plastic rings (6) have a wide fit around the coiled tubing (1) to be cleaned to suit. Device for external cleaning of pipes according to claims 1, 2 and 3, characterized in that the angle of the liquid jets with the surface of the coiled tubing (1) to be cleaned is between 85 and 65 degrees. 20 Device for external cleaning of pipes according to claims 1, 2, 3 and 4, characterized in that the device is provided with a pressure sensor which responds at pressures higher than 0.1 bar absolute. Device for external cleaning of pipes according to claims 1, 2, 3, 4 and 5, characterized in that the device is provided with a sensor which reacts when the coiled tubing (1) to be cleaned is stationary. 7. Device for external cleaning of pipes according to claim 1, 2, 3, 4, 5 and 6, characterized in that the cleaning liquid is water and touches the coiled tubing (1) to be cleaned with a temperature between 80 and 100 degrees Celsius . * * * * Λ ft t * jrc, 7 l U i i o w *