WO2014077697A1

WO2014077697A1 - Petroleum well imaging tool for a well object of unknown shape

Info

Publication number: WO2014077697A1
Application number: PCT/NO2012/050224
Authority: WO
Inventors: Dag Terje SVENDSEN
Original assignee: Archer Oil Tools As
Priority date: 2012-11-14
Filing date: 2012-11-14
Publication date: 2014-05-22

Abstract

A petroleum well imaging tool for a well object of unknown shape or orientation, wherein said petroleum well imaging tool comprises: - a main body (0) with a main axis (10), with a fishing neck (4) and a connector (5) in said main body's upper or outer end for a tool carrier, and with - a hole matrix (2) with a set of axially directed channels (211, 221) with a set of rigid, obtuse needles (1) arranged through said hole matrix (2) said hole matrix arranged in a lower or inner end of said main body (0) as counted in an axial direction in said borehole, - said needles (1) being generally axially parallel directed ahead and having their forward directed obtuse ends (11) in the initial state arranged in one plane and arranged to individually and under friction to be displaced rearwards upon collision with said well object upper / outer portion, - a cavity (6) behind the hole matrix (2) arranged for receiving said needles' rear ends (12), so as for said obtuse ends (11) after said collision forming a negative image (IM) of said objects upper or outer portion's shape.

Description

PETROLEUM WELL IMAGING TOOL FOR A WELL OBJECT OF UNKNOWN SHAPE

Introduction

[001] The invention is a petroleum well imaging tool for a well object of unknown shape. The invention is thus a tool for imaging an object in a petroleum well, where the shape of the object is unknown. The objective of the invention is to identify the shape of the object sufficiently to be able to grip and hold the object.

Introduction and problem to be solved

[002] The object may be any device which could end up in the well in a place where it should not be, e.g. the in place undesired device can be a tool which one has been lost down into the well, as spanners, tongs, gripping tools.

[003] Likewise, the object in the well may be equipment which one have lost down into the well, as valves, pipe sockets, nuts, bolts, metal rings, hooks, shackles, metal filters, entry cones, etc. which may have worked loose during well operations such as intervention, drilling, setting of casing, drilling of deviated branch wells, operation of valves, replacement of valves. Likewise, entire or parts of well tools may be lost down into a well during logging or intervention, either because a cable or wire line, carbon fibre based intervention rod or coiled tubing is broken, or that the well tool itself is broken or unscrewed into two parts in an undesired manner. There must be a fishing neck at the top of all logging- or intervention tools but if the break does not occur at a foreseen place in the metal structure in a logging- or intervention string, one has an object which must be fished up from the well .

[004] The following problem may then remain :

- is the available part of the object in the well in such a mechanical state that it can be gripped and possibly held to a degree that the object may be removed from the well?

- how does the available part of the object actually look from above? What is its shape in the available top? - how may the top available from above be gripped and possibly held with a fishing tool, i.e., how should a fishing tool be designed?

Background art in the area

[005] Traditionally, a so called "lead impression block" arranged in front of a tool butting against the object with an unknown shape or an unknown orientation has been used . An imprint will be created in the lead-disc. A major drawback with such a lead block is that the imprint from the object is very shallow, meaning that the information about the depth of the relief available for optionally gripping the the upper part of the object is quite limited .

[006] When knowledge about the objects shape and/or orientation has been obtained, a variety of tools for direct fishing without deep knowledge about the objects orientation or form exist. a. magnet fishing instruments with powerful Neodymium magnets attracting material with a certain minimum relationship between magnetic permeability and mass, like nuts, sleeves, bolts, valves of steel. Such magnets may give a holding force of several thousand Newton if they obtain a good faying against the magnetisable object. However, magnets perform poorly, or not at all on objects made of acid-resistant steel, or alloys that are not magnetisable. b. Sleeves with barbs being thread down and over and gripping about a collar or flange in the top of so called "fishing necks". c. fishing tools with forward directed screws being screwed into upward directed openings in the top of objects, either in existing threads or by self- threading . d. fishing tools with actuated griping claws gripping remains of wires. With the present tool it is of little relevance to create an imprint of something as soft as remains of wires, except if a quite short, stiff stud extends from an object in a well, but in any way it is much better than a lead impression block.

Short summary of the invention [007] The invention is a petroleum well imaging tool for a well object of unknown shape or orientation, wherein said petroleum well imaging tool comprises the following features:

- a main body (0) with a main axis (10), with a fishing neck (4) and a connector (5) in said main body's upper or outer end for a tool carrier, and with

- a hole matrix (2) with a set of axially directed channels (211, 221) with a set of rigid, obtuse needles (1) arranged through said hole matrix (2) said hole matrix arranged in a lower or inner end of said main body (0) as counted in an axial direction in said borehole,

- said needles (1) being generally axially parallel directed ahead and having their forward directed obtuse ends (11) in the initial state arranged in one plane and arranged to individually and under friction to be displaced rearwards upon collision with said well object upper / outer portion,

- a cavity (6) behind said hole matrix (2) arranged for receiving said needles' rear ends (12) so as for said obtuse ends (11) after said collision forming a negative image (IM) of said objects upper or outer portion's shape.

Short figure captions

[008] Fig . 1 is a vertical axial section view of a tool according to the invention.

[009] Fig . 2 is a plan view of a hole matrix (2) that is part of the invention. The plane view is perpendicular to the tools axis.

[0010] Fig . 3 is a detail of an embodiment of the invention where a lid constitutes an integrated part of the hole matrix.

[0011] Fig . 4 is a detail of another embodiment of the invention where an axial slender stem extends a fixed distance down or out of the hole matrix.

[0012] Fig . 5 is an axial parallel part of a sectional view and a view showing an embodiment of needles where heads have been formed on the faying side of the needles. [0013] Fig . 6 is an axial parallel section of a well imaging tool according to the invention leaning on an object in a deviately drilled well. The house of the well imaging tool is equipped with an asymmetric fishing neck connected to a hammer tool and a weight pipe. This arrangement forces the weight pipe and the hammer tool to lie on the "low side" inside the well and consequently the orientation of the object in addition to the image of the objects top will be known.

Embodiments of the invention

[0014] The invention is a petroleum well imaging tool for a well object of unknown shape. The invention is actually a tool for imaging an object in a petroleum well, where the shape of the object is unknown. It is therefore not imaging of the petroleum well itself that is the subject of the invention. The object of the invention is to identify the shape of the object to a degree sufficient to enable gripping and holding of the object.

[0015] The petroleum well imaging tool comprises the following features: a main body (0) with a main axis (10) that should essentially be axial parallel with a local long axis of the well. The tool is by default equipped with a fishing neck (4) (because it should in upcoming situations be possible to fish) and a connector (5) over the fishing neck (4), in said main body's upper or outer end for a general tool carrier. The main body shown in Fig . 1 has in an embodiment a diameter of 88,9 mm and a length of 170 mm including the fishing neck (4). The main body's upper part under fishing neck (4) is conical, as shown in Fig. 1, to prevent it from hooking up into something when it is pulled up from the well.

[0016] The tool carrier may be a drill string, a coiled tubing, a rigid rod, a wire line, or a tractor, for carrying said tool according to the invention into and out of said well, but it does not constitute the invention in itself.

[0017] The petroleum well imaging tool further comprises a hole matrix (2) with a set of rigid, obtuse needles (1) arranged through said hole matrix (2), everything arranged in a lower or inner end of said main body (0) as counted in an axial direction in said bore hole, The needles are in an embodiment of the invention about 4 mm in diameter. Smaller and larger diameters may be used . Their individual distance in the hole matrix is 2 to 4 mm. The needles (1) are generally axially parallel directed ahead and having their forward directed obtuse ends (11) in the initial state arranged in one plane and arranged to individually and under friction to be displaced rearwards upon collision with said well object upper / outer portion, In this respect the hole matrix resembles the shape of a toy where a large number of smooth pins are arranged in a hole matrix frame with e.g. 20 x 30 pins, where the complete hole matrix frame can be pushed against a relatively firm object and thereby achieve a negative imprint with the spatial resolution that the hole matrix frames regular needle distance gives. It is clear that the opposite ends of the needles creates a positive corresponding imprint, not so different from a raster image. The hole pattern, i.e. the needle pattern, is in the illustrated embodiment concentric rings of holes, where the rings have a steadily increasing radius, about a centre hole. In an embodiment of the invention one centre needle (1) (or centre short stem (13) and 7 concentric rings of holes with needles (1) in the hole matrix. It is clear that a hexa- symmetric pattern or square or rectangular raster alternative may be used.

[0018] Note that we write the needles obtuse ends, and not sharp ends. This is not for the sake of the object to be pushed against, but for the sake of achieving a clean axial butting against an obtuse, possibly mainly flat end of the needle, to a certain degree to avoid that two adjacent needles are bent around an

extending/protruding detail . In this respect the needles may be flat and rubbed at the end, to have a certain friction and not be to smooth in the downward directed or forward directed end surface.

[0019] Independent of whether the needles have a fore head or not, they are in general entirely plane grinded in the front and a bit rough and not smooth in front, to prevent them from slipping to the side of slender protruding parts of the object in the well.

[0020] The density of the hole matrix, i.e. the centre distance of the needles determines the resolution of the image that is created. It is only the negative imprint of the objects axial parallel projection that is created, but this can anyway give a much better image of the object to be fished than no information other than that there is an undesired object in the well.

[0021] A cavity (6) behind said hole matrix (2) is arranged for receiving said needles' rear ends (12), see Fig. 1. [0022] The obtuse ends (11) will be pushed axially inwards by the objects mechanical fixed parts such that they together, after the collision create a negative image (IM) of the objects upper or outer portion's shape. The negative image (IM) may be due to a protruding bolt, quite rigid, more or less fixed length of the end of a steel cable. (If an end of a steel cable or carbon fibre cable is frayed it will probably not have a sufficient strength to create an image), a rod, a ring, a ball, a flange, valve head, a cylinder, a threaded part, a tube stud, a torn coiled-tubing-end with 0 2 - 2 7/8" and a few mm wall thickness, a plate with a slit, a crack, a hole, internal threads, a grid, etc., that can be gripped and held by a fishing tool with a corresponding shape that can be created. Another problem that the tool according to the invention can contribute to the solution of, is in the case where there is nothing wrong with the well, or where there is no undesired object in the well, but a plug or any other object in the well should be removed or displaced, and that alternative embodiments of the object to be found exist, but there is no documentation about its upper end to be operated on. The tool according to the invention may contribute with sufficient information about the unknown shape of the objects top end to distinguish between the relevant alternatives.

[0023] The invention also comprises a method for imaging a well object of unknown shape or orientation in a petroleum well, comprising the following steps: inserting a petroleum well imaging tool of claim 1 ahead to said well object, and butting said needles' (1) obtuse ends (11) against said well object, so as for said obtuse ends (11) after collision form a negative image (IM) of the object's upper or outer portion's shape, and pulling said petroleum [well] imaging tool out of said petroleum well.

[0024] A fishing tool is formed by forming an inverse of the negative image (IM) so as for obtaining an approximate shape of the upper portion of said well object to be caught and held, and form a gripping tool with a grip shape with the actual shape, guide the so formed gripping tool down into the well and grip said well object.

[0025] In an embodiment of the invention the hole matrix (2) comprises at least an inner, perforated guide disk (21), and a perforated friction disk (23). The perforated guide disk (21) has axial parallel cylindrical channels (211) with a certain length arranged to held the needles (1) stable and let them slide under an axial directed thrust, and where the perforated friction disc (23) has

corresponding axial parallel cylindrical channels (231) arranged for creating friction and to keep the needles in place when the collision with the object comes to an end and an image has been created .

[0026] In a further embodiment of the invention the hole matrix (2) comprises an outer, perforated guide disk (22) arranged outside said perforated friction disk (23). This outer perforated guide disk (22), see Fig. 1, is separated from the inner perforated guide disk (21) by the perforated friction disk (23), and has axial parallel cylindrical channels (221) with a certain length arranged to keep the needles (1) and let them slide. The channels (221) and (211) are axially arranged over the whole hole matrix (2). The distance between the channels (221) and (211) in addition gives a bending moment resistance, thus keeping the needles axial parallel. The needles (1) are preferably made of hardened steel that cannot be easily bent, and if they should be bent, they will not break. It is not unlikely that they could be bent, but they can very easily be replaced . In a prototype the inventor has tried 80 mm long needles that are usually used in a so called abrasive tool. They have a diameter of 3 mm and are provided with a head as shown in Fig . 1, and have a plane grinded fore end (11) The guide disks in the prototype are steel disks with a thickness of 10 mm. 3,3 inches house (0) = 88,9 mm, being applicable for 4,5 " OD tubing with ID 3,8".

[0027] In an embodiment each said needle (1) is provided with a head (121) at its rear end (12), arranged for preventing them from running out through said hole matrix (2). If not, there is a risk that they would slide out if the pressure inside the cavity (6) becomes higher than in the well fluid around the house. The needles position after the imaging is stabilised since it is placed in the rubber hole matrix (23) that becomes narrower when it is squeezed between the outer and the inner guide disks (21, 22).

[0028] In an embodiment of the invention the main body (0) is axial cylindrical, and the hole matrix (2) is correspondingly circular. The hole matrix (2) is circular since at least the outer perforated friction disk is circular. The main body's (0) lower end (7) may comprise a lid (71) having an open front and arranged for firmly holding said hole matrix (2) at said main body's lower end (7). In the illustrated embodiment the lower end (7) is circular and threaded, and said lid (7) being circular and correspondingly threaded, and provided with a ring flange (72) arranged for holding the end of said hole matrix (2). The ring flange (72) has in the illustrated embodiment in Fig . 1 an opening reaching 2 - 5 mm in, over the hole matrix' (2) fore periphery. This gives a mechanical strength that is durable and that can endure the lowering into petroleum well. In an alternative embodiment illustrated in Fig. 4, the lid (7) and the outer friction disk (22) are made in one piece, so that the lid (7), instead of having a wide open front that keeps and fills the hole matrix (2), has an integrated, complete front constituting the outer perforated guide disk (22) and is equipped with axial parallel cylindrical channels (221) with a certain length arranged for keeping the needles (1) and letting them slide. The inner or outer guide disk (21) and the perforated friction disk (23) are kept in place by the lid (7). If necessary, it would have to screwed out an in with the needles (1) in place, where the entire hole matrix (2) with needles then must be rotated with the lid during assembling and disassembling . An advantage with this arrangement is that needles may be arranged closer to the main body's (0) OD, and that a more complete image of the peripheral parts of the object may be obtained.

[0029] The main body (0) comprises an inner edge (61) for forming a backing for said inner perforated friction disk (22) against the force from said lid (7). The inner edge (61) therefore holds the hole matrix (2) in place in the main body so that it does not slide inward the cavity (6).

[0030] In an embodiment of the invention the main body (0) is provided with a pressure alignment channel (9) in to the cavity (6) for aligning pressure between well fluids within the cavity (6) and well fluids outside the main body (0). The pressure alignment channel (9) let pressure from well fluid in from behind, like drilling fluid, completion fluid, gas, water, oil, so that the needles are not pushed inn by the pressure in the well when the tool is inserted into the well and the pressure gradient is positive, and let pressure out again when the tool is removed from the well so that the needles are not pushed back. After all, in the rubber plate (23) between the inner and the outer guide disks (21, 22) it is gas and fluid proof, if not it would be a risk that the needles would be displaced after the imprint of the image (IM) when the tool is lifted to the surface and the fluid pressure in the well is reduced since the hydrostatic columns height above the tools position is decreased .

[0031] According to an embodiment of the invention the main body (0) is provided with an axially displaceable cylindrical sleeve (75) outside, in order to protect said needles on their way down. The sleeve may be spring-loaded, and glidingly return back at a given force. The sleeve may also be provided with shear pins (76), e.g. made in brass or bronze, that would break at a given force when the tool according to the invention reaches the object for the first time and hits it with an impact of a given shear force. In this manner it is avoided that especially the needles in the outer part are pushed inn by protrusions in the well when the tool is on its way down into the well, which would result in a false peripheral image.

[0032] In an embodiment of the invention the fish neck is arranged axial parallel but asymmetrical with reference to the main axis (10), see Fig . 6. This is an advantage, since the hammer and the weight lead will ensure that the tool will remain lying in a certain lower position in a deviately drilled well, and that the position of the image with reference to the horizontal plane is obtained as well. In this way it is possible to confidently approach the object later with the specially constructed fishing tool when fishing is to be performed .

[0033] A further possible feature of the hole matrix (2) is to have a mainly centrally arranged fixed axial slender stem (13) between the needles (1). The fixed axial slender stem (13) extends a fixed distance out from said hole matrix (2) shorter than the needle's (1) fully extended length. The axial stem (13) will limit the imprint of the negative image (IM) in its depth (except if it is not butting against some part of the object in the well), making it possible to push with a certain force and not having to consider whether to push harder or softer against the object, and that the pressing in will continue until a certain minimum depth is reached.

[0034] According to an embodiment of the invention, one or more of said needles (1) are provided with a fore head (111) in their forward obtuse ends (11). The fore head (111) extends the area of the obtuse and (11) so that the fore obtuse ends of the needles cover the area in the front better. The risk of not detecting protruding, thin particles on the object in the well that could protrude between the fore ends of the needles, is then reduced .

[0035] According to an embodiment of the invention, the tool carrier comprises a drill string, a coiled tubing, a rigid rod, a wire line, or a tractor, for carrying said tool into and out of said well.

[0036] Above the tools connector (5), is in an embodiment of the invention a so called hammer, as shown in Fig . 6 arranged, independent of the whether the tools fishing neck is symmetrical with the axis (10) or not. The hammer is arranged to give the tool a small knock from behind when it is arranged against the top of the object to be imaged . In an embodiment of the invention, one or more weight pipes are arranged between the tool carriers' connector (5) and the tool carrier, preferably above the hammer.

Claims

1. A petroleum well imaging tool for a well object of unknown shape or orientation, wherein said petroleum well imaging tool comprises:

- a cavity (6) behind said hole matrix (2) arranged for receiving said needles' rear ends (12)

so as for said obtuse ends (11) after said collision forming a negative image (IM) of said objects upper or outer portion's shape.

2. The petroleum well imaging tool according to claim 1, said hole matrix (2) comprising at least an inner, perforated guide disk (21) comprising said channels (211), and a perforated friction disk (23).

3. The petroleum well imaging tool according to claim 2, wherein said hole matrix further comprises an outer, perforated guide disk (22) comprising said channels (221), arranged outside said perforated friction disk (23).

4. The petroleum well imaging tool according to claim 1, 2, or 3, each said needle (1) provided with a head (121) at its rear end (12), arranged for preventing them from running out through said hole matrix (2).

5. The petroleum well imaging tool of claim 1, 2, 3, or 4, said main body (0) being axially cylindrical, and said hole matrix (2) being circular.

6. The petroleum well imaging tool according to any of the above claims, said main body's (0) lower end (7) comprising a lid (71) having an open front and arranged for firmly holding said hole matrix (2) at said main body's lower end (7).

7. The petroleum well imaging tool according to claims 5 and 6, said lower end (7) being circular and threaded, and said lid (7) being circular and

correspondingly threaded, and provided with a ring flange (72) arranged for holding an end of said hole matrix (2).

8. The petroleum well imaging tool according to one of claims 6 and 7, said lid (7) and said outer guide disk (22) formed in one piece.

9. The petroleum well imaging tool according to any of the above claims, said main body (0) comprising an inner edge (61) for forming a backing for said inner perforated friction disk (22) against the force from said lid (7).

10. The petroleum well imaging tool according to any of the above claims, said main body (0) provided with a pressure alignment channel (9) in to said cavity (6) for aligning pressure between well fluids within said cavity (6) and well fluids outside said main body (0).

11. The petroleum well imaging tool according to any of the above claims, wherein said main body (0) is provided with an axially displaceable cylindrical sleeve (75) outside in order to protect said needles on its way down.

12. The petroleum well imaging tool according to any of the preceding claims, said fishing neck being asymmetrically relative to said main axis (10).

13. with a centrally arranged fixed axial slender stem (13) between said needles (1), extending a fixed distance out from said hole matrix (2) shorter than the needle's (1) fully extended length.

14. The petroleum well imaging tool of claim 1, one or more of said needles (1) provided with a fore head (111) in their forward obtuse ends (11).

15. The petroleum well imaging tool of claim 1, said tool carrier comprising a drill string, a coiled tubing, a rigid rod, a wire line, or a tractor, for carrying said tool into and out of said well .

16. The petroleum well imaging tool according to claim 15, wherein above said tool's connector (5) is arranged a so-called hammer.

17. The petroleum well imaging tool according to claims 15 or 16, wherein between said tool carrier's connector (5) and said tool carrier is arranged weight pipes.

18. A method for imaging a well object of unknown shape or orientation in a petroleum well, comprising the steps of:

- inserting a petroleum well imaging tool of claim 1 ahead to said well object, and butting said needles' (1) obtuse ends (11) against said well object, so as for said obtuse ends (11) after collision form a negative image (IM) of said object's upper or outer portion's shape, and pulling said petroleum [well] imaging tool out of said petroleum well, and reading said negative image (IM).

19. The method according to claim 1 [correction : claim 18], wherein a fishing tool is formed by forming an inverse of the negative image (IM) so as for obtaining an approximate shape of the upper portion of said well object to be caught and held, and form a gripping tool with a grip shape with the actual shape, guide the so formed gripping tool down into the well and grip said well object.