NL1019136C2 - Tools for cleaning wells. - Google Patents

Description

-1-

Tools for cleaning wells *

The invention relates to tools for cleaning oil and gas wells. The tool is fixedly mounted on a supply pipe and is provided with a rotating head which is provided with nozzles directed at the inner wall of the wellbore.

Oil and gas producing wells pollute during operation and a layer of sediment, often calcite, forms on the inner wall and disrupts the flow of oil or gas. Especially calcite and other calcium compounds are difficult to remove.

Mechanical brushes are often used, but the life of these devices is short and must be renewed a number of times per well.

A tool with nozzles is known from the American patent US-A-6,027,040. This tool is equipped with two nozzles which are placed eccentrically and at an angle. It has been found that the combination of eccentricity and angle leads to high speeds and therefore a low result. The tool loosens the contamination in too large chunks 15, so that the tool easily becomes stuck

The invention relates to a tool with a rotating head at the front with nozzles which lie at an angle and in the plane of the axis of rotation for effective cleaning. The rotation of the head is effected by two or more nozzles which are placed perpendicularly and eccentrically on the axis of rotation. These nozzles perpendicular to the axis of rotation have the secondary function of crushing the discharged chunks so that the head does not get stuck. In the fixed part, rear-facing nozzles are placed at an angle which have the function of removing the crushed inaccuracies from the tool. An eddy current brake can be placed in the tool to limit the speed of rotation.

By choosing the diameter of the different nozzles, the tool can be set for different types of iniquities. Calcite requires a different nozzle configuration than for hard paraffin.

The tool is fixedly mounted on a steel feed tube and fed with water under a pressure between 150 and 2500 bar.

Description of the invention.

FIG. 1 shows schematically the arrangement of the nozzles.

FIG. 2 shows a longitudinal section of the tool.

FIG. 3 shows the cleaning operation in a well bore.

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Fig. 1 schematically shows the configuration of the nozzles. Line (1) is the axis of rotation of the front rotating head (2). In head (2) there are two or more nozzles (3) at an angle (4) with respect to the axis of rotation (1) in the plane of the axis of rotation (1) is placed. The angle (4) is between 25 and 50 degrees, preferably 35 degrees, or one or more nozzles (5) are placed in the head (2). Nozzles (5) are positioned perpendicular to axis of rotation (1) with eccentricity (7). Due to eccentricity (7), nozzles (5) will cause the head (2) to rotate. The torque can be controlled by choosing the diameter of the nozzle and varying the eccentricity (7). With (8) the seal and the bearing of the rotary coupling are schematically indicated.

In the fixed part (9) three to 8 nozzles (10) are arranged which are directed at an angle (11) with respect to the axis of rotation (1) in the direction of the supply pipe (12).

In FIG. 2 is a schematic sectional view of the tool. The water supply pipe (12) under a pressure between 150 and 2500 bar is coupled at (13). Through the center of the tool is channel (14) with labyrinth seal (15). Shaft bearing with seals and eddy current brake are indicated without details with (16). In the head (2) are channels (17) which connect the nozzles to channel (14).

In FIG. 3, the tool in the well bore is indicated by drill pipe (18) and iniquities (19). The supply tube (12), which may be of the coiled tube type, serves as the supply of water under high pressure. The water jets from nozzles (3) cut the dirt and nozzles (5) crush the chunks and give rotation to the head (2).

Because the cleaning is done by jets of water, the tool is hardly subject to wear and it has been found that wells can be cleaned quickly and efficiently. The nozzle configuration and thus the choice of jet diameters make it possible to distribute the supplied water favorably over the various functions.

Claims (5)

A cleaning tool provided with a rotating head with nozzles and connected to a high pressure water supply for cleaning oil or gas wells, characterized in that the tool consists of a fixed part (9) and a rotating part (2) wherein the rotating part (2) is provided with two or more nozzles (3) which are placed forwardly at an angle (4) with the axis of rotation (1) and also one or more nozzles (5) are perpendicular to placed with respect to and at some distance from the axis of rotation (1) and in the fixed part 3 or more nozzles (10) which are placed rearwardly at an angle (11) with respect to the axis of rotation (1). Cleaning tool according to claim 1, characterized in that the forward-facing nozzles (3) are at an angle (4) between 25 and 50 and preferably at 35 degrees relative to the axis of rotation (1) in the plane of the axis of rotation ( 1). Cleaning tool according to claims 1 and 2, characterized in that the axis of the nozzles (5) placed perpendicular to the axis of rotation (1) is between 1 and 10 millimeters eccentrically (7) relative to the axis of rotation (1). 20 Cleaning tool according to claims 1,2 and 3 characterized in that the nozzles (10) placed in the fixed part (9) at an angle (11) between 40 and 75 degrees backwards relative to the axis of rotation (1) are placed. Cleaning method for oil or gas wells in which a cleaning tool according to claims 1 to 4 is introduced into a steel high-pressure pipe in the wellbore and is fed with water under a pressure between 150 and 2500 bar, the forward-facing nozzles (3) spray off the impurities and the perpendicular nozzles (5) crush the impurities and keep the rotating part (2) in rotation, the rearwardly directed nozzles (10) driving away the crushed impurities from the tool. * * * *