ELECTROCHEMICAL WELL PIPE CUTTING INSTRUMENT

Abstract

An electrochemical well pipe cutting instrument, applicable in particular for cutting any type of pipes accessing underground works with conductive fluid inside, includes at least one device for ensuring electrical continuity and at least one electrode. The instrument also includes at least one device for ensuring mechanical fixation of the instrument in the pipe such as an anchor. The device for ensuring electrical continuity, the anchor and electrode can be adjusted in length to suit different diameters of pipe within a large range. Optionally the electrodes are located on a rotary device. The instrument is connected to a main instrument body which includes an electronic module, at least one centralizer and a CCL module with an inclinometer. The main instrument body is connected to a cable head which ensures the communication to a surface unit.

Claims

1. An electrochemical well pipe cutting instrument, applicable in particular for cutting any type of metal pipes accessing underground works with conductive fluid inside comprising at least one means for ensuring electrical continuity; at least one electrode; and at least one means for ensuring mechanical fixation of the instrument in the pipe, wherein the means for ensuring electrical continuity is also the means for ensuring mechanical fixation.

2. An electrochemical well pipe cutting instrument according to claim 1, wherein the means for mechanical fixation is an anchor.

3. An electrochemical well pipe cutting instrument according to claim 2, wherein the means for ensuring electrical continuity, the anchor and the electrode are adjustable in length to suit different diameters of pipe within a large range.

4. An electrochemical well pipe cutting instrument according to claim 1, wherein the electrode is located on a rotary device.

5. An electrochemical well pipe cutting instrument according to claim 1, wherein the instrument is connected to a main instrument body which comprises an electronic module to deliver an adapted power supply to the electrode as required.

6. An electrochemical well pipe cutting instrument according to claim 5, wherein the main instrument body also comprises at least one centralizer.

7. An electrochemical well pipe cutting instrument according to claim 6, wherein the main instrument body also comprises a CCL module with an inclinometer.

8. An electrochemical well pipe cutting instrument according to claim 5 wherein the main instrument body is connected to a cable head which ensures the communication to a surface unit.

Description

DESCRIPTION OF THE DRAWINGS

[0077] To supplement the description in this document and in order to aid comprehension of the characteristics of the invention these specifications include as an accompaniment a set of illustrative, non-restrictive plans representing the following:

[0078] FIG. 1—Shows a vertical schematic view of an example of the well pipe cutting instrument comprising the invention, showing the principal parts and elements comprising the same;

[0079] FIG. 2—Shows an overall vertical view of the instrument connected to the cable, showing its arrangement and the devices involved in its operation, handling and control;

[0080] FIG. 3—Shows a vertical sectional view of the instrument in a well, connected to a surface unit by means of a self-supporting electric cable, that ensures communication and power supply, showing the arrangement of all surface equipment;

[0081] FIG. 4—Shows an enlarged and more detailed view of the previous section shown in FIG. 3, presenting work over rig, cable and surface unit used in said example

[0082] FIG. 5—Shows a further vertical sectional view of the cutting instrument inserted into the well and connected to another example of a surface unit. In this case with the crane being incorporated in the vehicle and without the cable passing through a lifting tower, it shows the underground cavity where the pipe to be cut is located.

PREFERRED EMBODIMENT OF THE INVENTION

[0083] The aforementioned figures together with the numbering used show an example of a preferred, but non-restrictive, embodiment of the above named electrochemical well pipe cutting instrument, comprising the parts and elements indicated and described in detail below.

[0084] Thus, as can be seen in FIG. 1, the instrument (1) in question, used for cutting pipes (2) in a well (3) accessing underground works (4), preferably with brine, comprises at least one mean for ensuring electrical continuity, such as arms, wires, anchors, fingers or packers, and at least one electrode (8).

[0085] Optionally the instrument (1) comprises at least one mean for ensuring mechanical fixation in the pipe such as centralizers, packers or extendable arms.

[0086] In a preferred embodiment the mean for ensuring electrical continuity is also the mean ensure mechanical fixation, especially an anchor (6).

[0087] In a preferred embodiment, there are more than one anchor (6) located, articulated and arranged radially at the same level. They open to reach the inner wall of the pipe (2), fixing the tool and adjusting to the right inner diameter.

[0088] In a preferred embodiment, the electrode or electrodes (8) are arranged radially on a rotary device (7), such that when rotating they are kept at a short distance from the pipe (2) wall, in order to adapt their position to the increasing diameter of said pipe (2), for which reason they are mounted on the end of dedicated arms (8a), so the electrolyte renewal is ensured at the same time by the rotating system.

[0089] By preference, the anchors (6) and the electrodes (8) are adjustable in length and are therefore suitable for any type of pipe within an extended range.

[0090] From FIG. 2, it can be seen that the instrument (1) is designed for connection to the lower end of the main instrument body (10) that includes as a minimum, an electronic module (11) to deliver an adapted power supply to the electrodes (8) as required. In order to achieve said connection, the body (5) of the cutting part (1) is equipped with connectors (22) for this purpose at its upper end.

[0091] In addition, said main instrument body (10) also carries at least one centralizer (12), preferably two, and a CCL module (13) with an inclinometer to both correctly locate the instrument (1) and inform about deviation of the pipe (2).

[0092] The main instrument body (10) has at its upper end a connector for connection to a cable head (15) by means of which it is held by the cable which ensures the communication to a surface unit (16).

[0093] The surface unit (16), as shown in FIGS. 3 to 5, is mobile and comprises a transport vehicle (17) to which the opposite end of the cable (15) is connected, to ensure power supply and communication. It is conveniently equipped with acquisition systems and a laptop to remotely control the instrument (9). The said cable (15) is used to run in (RIH) or to pull out (POOH) the instrument (9) and therefore to determine the level of the cut in the well with an accurate depth measuring device. The surface layout may either be a work over unit, an independent crane or a dedicated crane fitted on the vehicle (17) (FIG. 5). The pulleys (20) ensure correct guiding of the cable from the winch.

[0094] The following procedure aims at describing a standard field sequence of events for the well pipe cutting instrument: [0095] On-site installation of a logging unit, for example 7/32″ cable, up to 4500 m of standard cable, either surface pressure equipment or not depending on well conditions. [0096] Surface preparation of the instrument (9), connection of upper CCL inclinometer module (13), fast inspection test, rotation validation (7), electrodes opening and closing (8), anchors opening and closing (6), test on a jig at the same diameter of the pipe to cut. [0097] Electrical testing, cable (15) and cutting part (1) continuity tests, communication tests between surface unit (16) and downhole instrument (9). [0098] Rig up of all surface equipment above the Well-Head (3) if no pressure equipment is used. Otherwise run adapted the IWCF (International Well Control Forum) procedure. Lift up instrument (9) with winch (21) above the well-head (3). [0099] Zero depth on surface; start to run in hole (RIH) with instrument (9); Go down to the required depth. [0100] Check well conditions are good, looking at the tension, CCL and inclinometer (13) values. [0101] Pull Out Of Hole (POOH) and record a log (Tension/DSCL/Incl.) versus depth. Identify the best possible depth to cut. Go to the depth while POOH. [0102] Open anchors (6), and set instrument depth at the right position, and give some slack to the cable in order to ensure anchoring. [0103] Open the arms (8a) that hold electrodes (8) and start rotation (7). [0104] Step by step increase the current delivered to the electrodes (8) up to the maximum admissible level of intensity. [0105] Real time follow-up on screen of the main downhole instrument parameters (Intensity per electrode, Voltage, Power, Electronic module internal Temperature, Rotary engine power). [0106] Detection of the first piercing [0107] Keep on with the operation until detection of the end of the cut [0108] Stop the rotary device (7). Close arms (8a) that hold the electrodes (8). Check with CCL sensor that cut is complete. Pull out of hole (POOH) the instrument up to the surface. [0109] Potentially run additional surveys instruments like sonar or any relevant logging tool [0110] Rig-down equipment. Depart from site.

[0111] The nature of the present invention having been sufficiently described, as well as the means of its use, a more extensive explanation is not considered to be necessary in order that any expert on the subject might understand its scope and the advantages it offers. It should nevertheless be noted that its essential design may be put to use in other ways that differ in detail from that indicated in the example and that will also fall within the scope of the protection sought provided that the fundamental principle of the invention is not altered, changed or modified.