1. Field of the Invention
The present invention relates to a device for the selective propulsion or movement of a well tool. More particularly, it relates to a device for controlling the movement of a well tool which is used in petroleum wells in connection with the recovery of petroleum products or servicing/intervention in petroleum wells. The movement in the form of propulsion and/or rotation of the well tool is provided by means of magnetic forces. The invention also relates to a method for the selective movement of a well tool in or through at least a portion of a pipe string.
By the concept well tool is meant herein any equipment which is arranged to be run into and operated within a well in connection with the operation and servicing thereof.
2. Description of the Related Art
According to prior art a well tool is run into the well by being lowered, under the influence of gravity, into the well, hanging on, for example, a steel rope, a so-called “wireline”. In portions of the well, in which gravity cannot be utilized to drive the tool into the well, propelling devices may be used, such as so-called well tractors, pulling or pushing the tool in the longitudinal direction of the well. In some cases so-called coiled tubing is also used to drive the well tool to its location of use.
There are several drawbacks related to the prior art mentioned above.
The above-mentioned prior art is based on there being a physical connection between the well tool and a portion of the well located on the surface. To prevent leakages from the well into the atmosphere, extensive surface lock-gate tools are required. In addition extensive run-in equipment is required and a manning of 2 to 10 persons, depending on what equipment is to be run into the well. In addition, the area at the well surface is considered to be a hazardous area for personnel because of pressurized equipment, movable parts and the lifting and moving of heavy equipment.
Due to the extensive equipment required and the hazards connected with the above-mentioned prior art operations, it is a time-consuming process to install the well tool and pressure test the surface pressure control system of the well. This entails that the production from the well will have to be shut down for a relatively long time. Additionally, for reasons of safety, it may be necessary to shut down wells located in the area where heavy equipment is being lifted.
The invention has as its object to remedy or at least reduce one or more drawbacks of the prior art.
The object is achieved through the features specified in the description below and in the subsequent Claims.
In this document positional specifications, such as “upper” and “lower”, “bottom” and “top” or “horizontal” and “vertical”, refer to the position that the equipment is in the following figures, which may also be a natural, necessary or practical position of use.
In one aspect the present invention is constituted by a device for the selective movement of a well tool in or through at least one portion of a pipe string, said at least one portion of the pipe string being provided with a plurality of electromagnets which are arranged to move the well tool in said at least one portion by means of magnetic influence on said well tool. By the concept selective propulsion is meant, in this connection, that the movement of the well tool, with respect to both the direction of propulsion and/or the direction of rotation and also the speed within the pipe string, is arranged to be controlled from a control room on a drilling rig, for example. To provide as much protection as possible against external influence, each single electromagnet is preferably integrated, partially or entirely, into a substantially complementary recess in a portion of the internal wall surface of the pipe string.
Whenever there is a need for movement of the well tool in the longitudinal direction of the pipe string, said plurality of electromagnets in the at least one portion of the pipe string are placed, in one embodiment, one behind the other in the longitudinal direction of the pipe string. For the propulsion through the longitudinal direction of the pipe string it is advantageous, but not necessary, for said plurality of electromagnets to be annular and extend around a portion of the internal wall surface of the pipe string.
In one embodiment each one of said plurality of electromagnets that are placed one behind the other in the longitudinal direction of the pipe string, is constituted by at least one chip-like electromagnet located in only a portion of the internal circumferential portion of the pipe string. Preferably, two or more chip-shaped electromagnets are approximately equally spaced around a portion of the internal wall surface of the pipe string. In a preferred embodiment the chip-shaped electromagnets which are arranged one behind the other in the longitudinal direction of the pipe string, are placed on one or more lines extending substantially parallel to the centre axis of the pipe string. In alternative embodiments the chip-shaped electromagnets which are arranged one behind the other in the longitudinal direction of the pipe string, are placed randomly or along lines which do not extend parallel to the centre axis of the pipe string, for example but not limited to lines extending helically round the longitudinal axis of the pipe string.
When there is a need for a well tool to be rotated in a portion of a well pipe, for example a rotary pump, said plurality of electromagnets is placed in a portion of the well pipe and distributed substantially equally spaced round a portion of the well pipe. The electromagnets are arranged to create a magnetic field which moves in terms of rotation in a plane substantially perpendicular to the longitudinal axis of the pipe string. A well tool, such as a pumping device, could thereby be influenced by the magnetic field to rotate around the centre axis of the well pipe.
The power supply to the electromagnets is controlled sequentially between the individual adjacent-magnets by means of control devices known per se. The polarity of the individual magnet is synchronized with the movement of the well tool and thereby with the magnetic influence on the well tool, either to provide propulsion along the longitudinal axis of the well pipe or pipe string, or to provide rotation of the well tool around the centre axis of the well pipe in the desired direction and at the desired speed.
To be able to ensure that the well tool is moved substantially centred in the pipe string, the well tool is provided, in a preferred embodiment, with centering or guiding devices. In their simplest form, the guiding devices may be constituted by mechanical means known per se, such as, but not limited to, rolling devices or other guiding means substantially bearing on portions of the internal wall surface of the pipe string. Alternatively or in addition to said mechanical guiding devices, the guiding device or centring means of the well tool may be constituted by magnets, which are used in a manner known per se, for example as known from lateral guiding of so-called “MagLev” trains, to centre the well tool in a pipe string.
When there is a need for magnetic forces that are more powerful than the forces provided by the influence of the electromagnets on the well tool alone, the well tool may also be provided with magnets cooperating with the electromagnets placed in the wall portion of the pipe string. Preferably, the magnets, which are placed on or integrated into the well tool in such a case, are permanent magnets. Even though electromagnets placed on the well tool could provide a further enhanced magnetic effect compared with said permanent magnets, electromagnets placed on the well tool have the disadvantage of the well tool then requiring a power supply and thereby cables extending between the well tool and the surface of the well. Essential, advantageous features of the invention will thereby be lost.
The invention also relates to a method for the selective movement of a well tool in or through at least a portion of a pipe string, the method including the following steps:
In the following there is described a non-limiting exemplary embodiment of a preferred embodiment which is visualized in the accompanying drawings, in which like or corresponding parts are indicated by the same reference numeral, and in which:
In the figures the reference numeral 1 indicates a well pipe forming a portion of a pipe string 2 and being provided, in a portion, with a plurality of electromagnets 3 which are fixed in a recess 5 in the well pipe 1. Thus, the electromagnets 3 will have a portion exposed to the well. To avoid direct exposure to the well a protectant (not shown) may be applied to the outside of the electromagnets 3. Such a protectant may be for example, but not limited to, a suitable type of pipe or a coating which is fit to resist the environment of the well.
The electromagnets 3 are supplied with power from the surface through a power cable 42, control system 22 and power cable 43. In an alternative embodiment (not shown) the electromagnets 3 are supplied with power from the surface through a cable integrated into a portion of the pipe string 2. The electrical connection between the individual well pipes 1 is provided in the latter case by means of electrical connections which are integrated into the threaded portions of the individual pipes 1, which are used to form the pipe string 2.
In
The check valve 20 in
To achieve sufficient fluid-tightness in the annulus between the check valve 20 and the portion with electromagnets 3 and also the securing means 9, the check valve 20 is provided with flexible bushings 24 arranged to be brought to bear on the electromagnets 3 and the securing means 9, at least when the check valve 20 is driven in the upward direction in the well pipe 1. The bushings 24 could also effect centring of the check valve 20 in the well pipe 1.
The way the check valve 20 is configured in
To prevent the check valve 20 from being moved out of the portion with electromagnets 3, the well pipe 1 is provided with portions of reduced internal diameter in relation to the diameter of the portion of the well pipe 1 in which the check valve 20 can be moved. Such a precautionary measure is important should an uncontrolled loss of power supply to the electromagnets 3 occur. A skilled person will know that the check valve 20 is arranged to be expanded to the desired diameter after having been run in to the desired position in the well, and that it is arranged to be retracted to the necessary reduced diameter by means of a pulling tool (not shown), known in itself, which is used in connection with the extraction of the check valve 20.
To ensure that the pumping device 20, 28, 30 is secured at the desired location in the well, the pumping unit 30 is provided with a latching device 32 which is arranged, in a manner known per se, for example by means of spring-loaded latching elements, to be brought into engagement with complementary recesses 34 in a portion of the pipe string 2. The latching device 32 can be disengaged from the recesses 34 by means of a pulling tool (not shown), known per se. In
To ensure that the magnetic field provided by the electromagnets 3 will continuously influence the tool 40, the distance between the groups of electromagnets 3 in two interconnected well pipes 1 is preferably smaller than the extent of the tool 40 in the longitudinal direction of the pipe string 2.
In
In the exemplary embodiments shown in
In
In
Number | Date | Country | Kind |
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20052539 | May 2005 | NO | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/NO2006/000183 | 5/18/2006 | WO | 00 | 11/26/2007 |
Publishing Document | Publishing Date | Country | Kind |
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WO2006/126886 | 11/30/2006 | WO | A |
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20080202768 A1 | Aug 2008 | US |