Patent application title: LONG THIN STRUCTURES FOR GENERATING AN ENTANGLED FLOW RESTRICTING STRUCTURE
Folkers Eduardo Rojas (Boston, MA, US)
Alexander H. Slocum (Bow, NH, US)
IPC8 Class: AE21B2108FI
Class name: Wells processes placing or shifting well part
Publication date: 2013-11-14
Patent application number: 20130299191
A wire includes a plurality of units. Each unit has a relatively stiff
region joined to an intermediate region. The intermediate region has a
varying stiffness along its length. The intermediate region is joined to
a relatively pliable region.
1. A wire comprising: a plurality of units, each unit having: a
relatively stiff region joined to an intermediate region, the
intermediate region having a varying stiffness along a length of the
wire, and the intermediate region being joined to a relatively pliable
2. The wire of claim 1, further comprising a stinger coupled to a distal end of the wire.
3. The wire of claim 2, wherein the stinger further comprises a flexible body.
4. The wire of claim 2, wherein the stinger further comprises a pair of flexure legs.
5. The wire of claim 4, wherein the flexure legs comprise a shape memory alloy.
6. The wire of claim 2, wherein the stinger includes a trigger switch that, when activated, causes the stinger to deploy.
7. The wire of claim 6, wherein the stinger includes a torsion spring and a shell, in which activating the trigger switch causes the torsion spring to rotate the shell.
8. The wire of claim 1, further comprising a plurality of entanglement-promoting features disposed along a body of the wire.
9. The wire of claim 8, in which the plurality of entanglement-promoting features includes a hook disposed along the body of the wire.
10. The wire of claim 8, in which the plurality of entanglement-promoting features includes a deformable beads disposed along the body of the wire.
11. The wire of claim 8, in which the plurality of entanglement-promoting features includes regions of varying surface roughness along the body of the wire.
12. The wire of claim 8, in which the plurality of entanglement-promoting features includes an entanglement-promoting coating.
13. The wire of claim 12, in which the entanglement-promoting coating is creep-capable.
14. The wire of claim 12, in which the entanglement-promoting coating is swellable.
15. The wire of claim 8, in which the plurality of entanglement-promoting features includes a barb.
16. The wire of claim 1, in which the wire is included as a discrete strand of a cable.
17. The wire of claim 1, further comprising a creep-capable material contained in a hollow portion of the wire.
18. The wire of claim 13, in which the creep-capable material is selected from the group consisting of: a thermoplastic, a thermoresin, a heat-activated polymer, a pressure sensitive adhesive, a temperature sensitive adhesive, and a polymer that can flow at temperatures above 50 degrees C.
19. A wire having a distal end and a body comprising: a stinger coupled to the distal end of the wire, wherein the body of the wire has varying stiffness along the body.
20. The wire of claim 19, in which the body includes at least two different materials.
21. The wire of claim 19, in which the body includes a plurality of entanglement-promoting features.
22. The wire of claim 21, in which the plurality of entanglement-promoting features includes a hook disposed along the body of the wire.
23. The wire of claim 21, in which the plurality of entanglement-promoting features includes a bead disposed along the body of the wire.
24. The wire of claim 21, in which the plurality of entanglement-promoting features includes regions of varying surface roughness along the body of the wire.
25. The wire of claim 21, in which the plurality of entanglement-promoting features includes an entanglement-promoting coating.
26. The wire of claim 21, in which the plurality of entanglement-promoting features includes a barb.
27. The wire of claim 19, wherein the stinger further comprises a flexible body.
28. The wire of claim 19, wherein the stinger further comprises a pair of flexure legs.
29. The wire of claim 28, wherein the flexure legs comprise a shape memory alloy.
30. The wire of claim 19, wherein the stinger includes a trigger switch that, when activated, causes the stinger to deploy.
31. The wire of claim 30, wherein the stinger includes a torsion spring and a shell, in which activating the trigger switch causes the torsion spring to rotate the shell.
32. A method of controlling fluid flow in a wellbore comprising: coating a wire with a coating selected from the group consisting of a creep-capable material and a swellable material, thereby forming a coated wire; and continuously feeding the coated wire into the structure.
33. The method of claim 32, in which the creep-capable material is selected from the group consisting of: a thermoplastic, a thermoresin, a heat-activated polymer, a pressure sensitive adhesive, a temperature sensitive adhesive, and a polymer that can flow at temperatures above 50 degrees C.
 This application claims priority to U.S. Pat. App. 61/646,328, filed May 13, 2012, the entirety of which is incorporated by reference herein.
 The present disclosure relates to wire and leading end structures for injecting into a flow stream to controllably create a flow resistance. The technology disclosed can be used, among other ways, with the techniques described in U.S. Pat. App. 61/646,319, filed May 13, 2012, and co-pending patent application Ser. No. 13/893,152, filed May 13, 2013 by the inventors of the current application. The entireties of both of these applications are hereby incorporated by reference herein.
 The present disclosure relates to shapes, structures, and configurations of continuous media (including but not limited to wire) to promote entanglement in a flowing medium (i.e. liquid, gas, and combination thereof) to create in a controlled manner a flow resistance.
 Currently, blowout preventers (BOPs), are the primary safety device for controlling an oil well in the case of an unwanted influx of formation fluids entering the well. When a BOP fails, currently the main recourses are to either inject a "junk shot" below the BOP to plug the flow through the BOP, or drill a relief well to pump in concrete into the well to seal the high pressure region. The junk shot injects (pumps) large quantities of discrete pieces of material (e.g. pieces of rope, balls, etc.) with the intent that some of the materials will hang up on features inside the wellbore and then further bits of junk will build up behind; this approach is difficult because it can suddenly stop the flow and generate a pressure wave that can break the casing rupture disks and fracture the formation thus damaging the well and the reservoir. This can result in the entire reservoir being lost through the casing and fractured formation which then could catastrophically leak to the surface over a wide area. Drilling a relief well can take months to complete, during which time the well continues to produce out of control. Therefore, an alternative solution is needed to controllably close off uncontrolled flow through a damaged BOP.
 Among other things, an object of the present disclosure is to provide a long thin structure, such as (but not limited to) a wire, for incrementally reducing uncontrolled flow in a device by feeding a wire into a flow device, by entangling to form a structure that grows as more is fed into the flow until the desired flow resistance is achieved.
 Another object is to provide continuous structural connectivity through the resultant plug, as opposed to a plug created from discrete elements, to provide strength to the plug and resist breakup and failure of the plug due to high pressure fluid acting the plug.
 Another object is to provide deforming features that can interact (e.g. creep (i.e., flow together to close gaps), fuse, melt, etc.) to make the entanglement a cohesive plug to block the flow of fluid and gas.
 In general, in one aspect, a wire includes a plurality of units. Each unit has a relatively stiff region joined to an intermediate region. The intermediate region has a varying stiffness along its length. The intermediate region is joined to a relatively pliable region.
 In general, in another aspect, a wire having a distal end and a body includes a stinger coupled to the distal end. The body has a varying stiffness.
 Implementations may have one or more of the following features: the stinger includes a flexible body. The stinger includes a pair of flexure legs. The flexure legs comprise a shape memory alloy. The stinger includes a trigger switch that, when activated, causes the stinger to deploy. The stinger includes a torsion spring and a shell, in which activating the trigger switch causes the torsion spring to rotate the shell. The wire also includes a plurality of entanglement-promoting features disposed along a body of the wire. The entanglement-promoting features include a hook, a deformable bead, a region of varying surface roughness, a coating, and a barb. The wire includes a creep-capable material. The creep-capable material coats the wire. The creep-capable material is contained in a hollow portion of the wire. The creep-capable material is a thermoplastic, a thermoresin, a heat activated polymer, or a pressure and/or temperature sensitive adhesive, or a polymer that flows at temperatures above 50 degrees C.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1a shows a wire with integral features in the cross section;
 FIG. 1b shows a wire with features to promote entanglement cohesion;
 FIG. 1c shows a wire bundle with discrete features intertwined along the length;
 FIG. 1d shows a chain structure that can feed into the flow stream;
 FIG. 2a shows a flat ribbon wire;
 FIG. 2b shows a flat ribbon in a collapsed configuration;
 FIG. 2c shows a helical ribbon wire;
 FIG. 3a shows a ribbon wire whose thickness varies along its length;
 FIG. 3b shows a cylindrical wire with varying features along its length;
 FIG. 3c shows a pipe where a stiff wire provides structural support and a flexible wire fills in the open regions to provide a seal;
 FIG. 3d shows a series of stiff and flexible sections used to create a fused entanglement plug;
 FIG. 4a shows wires with spherical elements along its length;
 FIG. 4b shows wires with cylindrical elements along its length;
 FIG. 4c shows wires with barbed elements along its length;
 FIG. 4d shows barbed wire strand as part of a pair of coated wire bundles;
 FIG. 5 shows feeding rollers for wires with inclusions along its length;
 FIG. 6shows a parallel wire bundle that can be fed simultaneously into the wellbore;
 FIG. 7 shows feeding mechanism pulling a parallel wire bundle from a wire spool;
 FIG. 8a shows a stinger at the tip of the wire to guide the wire into a wellbore;
 FIG. 8b shows a stinger that guides wire into wellbore and with a flexible body and features along length of body used for entangling;
 FIG. 8c shows a stinger with a rigid body and features along the body for generating entangling;
 FIG. 9 shows a flexural stinger at the tip of the wire;
 FIG. 10a shows an isometric view of a deployable stinger;
 FIG. 10b shows a cross sectional image of the unit mention in FIG. 10a;
 FIG. 10c shows a deployable singer in the deployed configuration;
 In the drawings, embodiments are illustrated by way of example, it being expressly understood that the description and drawings are only for the purpose of illustration, and are not intended as a definition of the limits of the invention.
 As described in the co-pending utility application described above, one approach to limiting fluid flow through a pipe, conduit, or other flow device involves continuously feeding a long, thin structure into the flowing medium. The long, thin structure is taken up by the fluid flow, and may interact with itself or other features in the environment to become tangled, thereby forming a plug that reduces fluid (i.e., liquid or gas) flow. As more of the long, thin structure (wire or various types and configurations as set forth herein) is fed in, the size of the plug increases, and thus further reduces the fluid flow in the environment. The techniques and structures described below, among other things, describe various designs of long, thin structures that promote self-interaction, thereby increasing the efficacy of plug formation in a flowing environment.
 In what follows, the term "wire" is used for a long, thin structure. It should be understood, however, that the term "wire" cover any structure capable of being fed continuously into a flowing environment. This includes structures that may not ordinarily be considered "wires," such as chains, and hollow tubing.
 A wire 1 according to the techniques below can be constructed from any combination of suitably stiff and suitably flexible material to allow the formation of nest-like structures by entanglement. In some implementations, the wire 1 is constructed from a material sufficient to withstand the environment of a typical oil wellbore, which is typically hot (e.g., temperatures exceeding 60 degrees C.), hydro-carbon rich, varying fluid mixtures, and in high-pressure conditions (e.g., pressure exceeding 5000 psi). In some implementations, a wire 1 can be made from any of many types of metal including but not limited to steel, aluminum, brass, magnesium or other alloys such as Nitinol (Nickel Titanium) and or polymers including but not limited to polypropylene, nylon, Kevlar, PVC, silicone rubber, or blends thereof. Natural fiber, such as hemp, can also be employed as a rope that is fed into the wellbore. In some implementations, the wire can be made of a combination of materials, for example a brass wire with a silicone sheath that softens once deployed into the flow stream to create a binding material in the entanglement structure. The binding material further aids in the restriction of gaseous medium flow as well as liquid flow.
 Referring to FIG. 1a, a wire 5 has an irregular cross section with integral features 6a, 6b, 6c, 6d that help to give the wire 5 buckling resistance during insertion. Inside an environment such as a wellbore, these features help to increase turbulence and hence resistance to the flow which in turn helps to increase tangling of the wire 1 to create a blockage. In some embodiments, these features can be designed to interact with other features along the wire 1 to promote entanglement strength. For example, FIG. 1b shows a wire 7 with integral features 8a-8r to promote entanglement cohesion. As the wire 7 buckles and bends the integral features 8a-8r can interact with each other, thereby surrounding and interconnecting structure 9b to promote a plug strength. For some embodiments, the core 9a of the wire 7 is hollow or filled with a medium (e.g. thermo resin, plastic, etc.) that is released into the flow to promote entanglement cohesion. The hollow body 9b of the wire 7 can collapse in the wellbore. In some embodiments, the medium may heat up in the wellbore environment to the extent where it can creep to help fill gaps in the entanglement structure or to help intra-wire cohesion, thereby strengthening the entanglement structure.
 In another embodiment, shown in FIG. 1 c, a wire bundle 10 has discrete strands intertwined 11a, 11b, 11c, 11d, 11e to form a cable. Each strand of can vary in material, yield criteria, surface friction, etc. The surface roughness of the wires can also vary amongst each strand and along their length 12b, 12c. For example, having small hooks oriented in one direction, such that the friction between individual strands of wire 10 increases thus further promotes generating a tangled nest-like structure.
 Referring to FIG. 1d, a chain 13 having a series of interlocked regions 14a-14o that are connected to form a continuous structure. The shape, stiffness, of each interlocked region 14a-14o can vary in each section. In some embodiments, the interlocking regions 14a-14o can also have features to promote entanglement.
 Referring to FIG. 2a, a wire 15 whose cross sectional area 16 is non-circular and whose stiffness along its length can vary along its length to encourage bending and twisting at specified sites 17a, 17b. As the wire 15 bends along the specified sites 17a, 17b the straight cross sections 18a-18c collapse on each other to reduce the flow across the entanglement, as shown in FIG. 2b.
 FIG. 2c illustrates a wire 20 that is helically twisted along its length to promote flow reduction. In some embodiments, the cross section 21 of the helical wire 10 can be irregular.
 Properties of the wire can be modified in a number of ways including but not limited: 1) heat treatment, 2) coating, 3) roughing purpose, 4) shielding, among other ways.
 Wires 25 and 28 with variable stiffness along their lengths are shown in FIGS. 3a, and 3b. For example, stiffness in a ribbon wire 25 can be modified by changing the cross sectional surface 26a, 27a, 26b, 27b, material, dimensions, coating, etc. The physical structure of the wire 1 can be altered by heat treatment for different areas, which creates ductile and rigid sections. The wire 1 will then be more likely to buckle in regions of low yield stress. The wire 1 could be asymmetric 25 or symmetric 28 with varying cross sectional area.
 A wire 1 can be coated, or constructed at least in part from with any suitable material to promote entanglement. For example, as discussed below, when an insulated wire (metal wire with plastic coating) is deployed in an environment containing relatively hot hydrocarbons, the plastic insulation may completely or partially melt, thereby becoming sticky and promoting intra-wire cohesion, which in turn promotes maintaining an entangled structure. More generally, any coating in the nature of a heat- or hydrocarbon-activated adhesive can be used at various sites along the wire 1 to promote cohesion and/or entanglement. For example, a plain round wire 1 (solid, braided or stranded) can be coated with a polymer, such as one would find in electrical wire. Another option is to coat any of the wire 1 variations disclosed herein, and still another option is coat any wire 1 (e.g. commercial barbed wire) with a plastic such as polyurethane or PVC. In general, appropriate coatings can also include (but are not limited to) a pressure sensitive adhesive, a temperature sensitive adhesive, a thermoplastic, a thermoresin, a heat-activated polymer, or a polymer that can flow at the ambient temperature of the wellbore. Typically, such temperatures are at least 50 degrees C.
 Moreover, such coatings can also be beneficial insofar as they may have a tendency to partially or totally melt, or otherwise become fluid like, in the relatively hot wellbore environment. Thus, such coatings may have a tendency to creep into gaps in the entanglement, thus further limiting the flow in the wellbore.
 Similarly, the wire 1 can be coated with, or be constructed at least in part from, a swellable material. Such materials include, but are not limited to, certain elastomeric matrix materials to which super absorbent polymer molecules have been added. Such particles can include starch systems, cellulose systems, and synthetic resin systems. Further description of other swellable materials can be found in U.S. patent application Ser. No. 12/665,160, the entirety of which is incorporated by reference herein.
 FIG. 3b illustrates a wire 28 whose cross sectional area varies along its length. The relatively thin regions 29b, 29e, 29h, provide a preferential regions to flex and buckle while the relatively thick regions 29a, 29d, 29g deform but not as significantly. Intermediate regions of continuously-varying thickness 29c, 29f, 29i can be used to provide a gradual transition to the flex region. Similarly, in some implementations a wire can have relatively stiff and relatively pliable regions, connected by intermediate regions of continuously-decreasing pliability. Thus, a wire 1 can be comprised of several "units," with each unit having a relatively thick (or stiff) region, followed by an intermediate region of continuously-decreasing thickness (or stiffness), followed by a relatively thin (or pliable) region. Here, the term "relatively" connotes the fact that, when compared to each other, the various sections are thicker/stiffer or thinner/more pliable than other sections. In particular, the term does not imply the exercise of any judgment to decide what qualifies as thick, thin, stiff, or pliable.
 Referring to FIG. 3c, feeding wires 68 and 69 of different stiffness into the flow 4 inside a flow device (e.g., a pipe) 2 leads to an anchoring feature that provides support for a relatively pliable wire 69 to pack and seal the gaps left by the stiffer wire 68. Variability along the length of the wire 1 can also be used to create an entanglement that is periodic in nature going from stiffer wire 68a to less stiff wire 69a, 69b, back to stiffer wire regions 68b, 68c, and so forth, as shown in FIG. 3d. The stiffness between the different sections of stiff wire 68a, 68b, 68c and less stiff wire 69a, 69b can also differ. In some implementations, a wire includes a relatively thick and/or stiff region at a distal end (i.e., the end of the wire that first enters the wellbore), and a relatively thin and/or pliable region thereafter (i.e., in the middle of the wire or at a proximal end of the wire). In some implementations, the thickness and/or stiffness of a wire 1 decreases monotonically along the longitude of the wire 1 from one end to another (e.g., from the distal end to the proximal end).
 Wires 1 with periodic or aperiodic entanglement-promoting features along their length could also be used to promote entanglement. An "entanglement-promoting feature" is any structure or element along the wire 1 that potentially may interlock or stick, even temporarily; with another such feature at another location along the wire 1 or with the wire 1 itself. For example as shown in FIG. 4a, a wire 30 with beads of varying diameter 31a, 31b, 31y could be used to promote entanglement. In some implementations, the beads 31a, 31b, 31y, can deform and the intermediate sections 32a, 32b allow for the beads to compress into an entangled nest. Other alternative embodiments, referring to FIG. 4b, are wires 35 with beads 36a, 36b, 36y which can be partially composed of a binding compound that is gradually melted to fill in gaps and solidify to form a solid entangled plug. Other alternative embodiments, referring to FIG. 4c, is a continuous structure similar to a barbed wire 32e with barbs 41a, 41b, 41y that can interact with each other, the surroundings, and any other structure. Other types of features such as hooks can also be used.
 Referring to FIG. 4d, a wire 42 that consists of two bundles with integrated barbs 41c, 41d, 41e, 41f. The individual strands 44a, 44b, 44c, 44d, 44e, 44f that make up the bundles have coatings 43a, 43b, 43c, 43d, 43e, 43f that can deform or partially melt. Although only two bundles are shown in FIG. 4d, in general any number can be used.
 As shown in FIG. 5, feeding a wire 45 with periodic features 46 could be done using drive wheels 48 that have recesses (pockets) 47 to accommodate the periodic features 46. In some embodiments, the feeding system can feed wires with non-periodic features. For example, the drive wheel can include a compliant channel that deforms around such features during the feeding process.
 As shown in FIGS. 6 an 7, multiple wire group 70 with individual wires 71a, 71b, 71c, 71d, 71e that are not bonded together can be fed with rollers 49 simultaneously from a spool 71 into a wellbore. In some embodiments, the gripping surfaces 72 of the drive system are modified to maintain the wire group 70 from traversing off the rollers 49. The feeding mechanism for the wires 1 is not limited to drive wheels but can also include the use of drive belts, gripping pads, etc. In some embodiments, features on the wire 1 can include pocket like structures to push the wire 1 into the wellbore hydrodynamically.
 Stingers at the tip of the wire 1 can be used to assist the wire 1 to initially go through valves and other channels prior to entering a wellbore into the flow stream. A "stinger" is a structure that helps a wire 1 get taken up in the flow of the surrounding fluid and then later gets entangled in a discontinuity in the flow path and thus helps to promote formation of the wire 1 tangle to control the flow. In some embodiments, the length and flexibility of the stinger varies and features as described above are included to further promote entanglement.
 FIG. 8a shows a simple stinger 50 in the shape of a bullet, with a conical head 51 and a cylindrical body 52. The rear of the stinger 3 is connected to the wire 1 that is being fed into the flow cavity. In some embodiments, the body 52 of the stinger 50 can have entanglement promoting features as described above. For example the stinger 55, illustrated in FIG. 8b, has features on the body 56a which can include a flexible or semi-flexible core that has hooks 57 for entangling. In another embodiment, shown in FIG. 8c, a stinger 60 whose body 63 has region 62 that includes barbs 61a, 61b. The body 63 can either be rigid or allowed to flex to promote wire entanglement.
 FIG. 9 shows a passively activated flexural stinger 75 operable to expand once it is in the wellbore to create turbulence and act as a seed to make an entangled nest. In the undeployed configuration the flexural stinger 75 can be fed through a small aperture. When the flexural stinger 75 enters the wellbore the preload on the flexure legs 76 is released thus changing shape to promote entanglement in the wellbore. This can be accomplished by the flexure legs 76 being held closed before it is fed into the wellbore, or the flexure legs 76 can be made of a shape memory alloy, that is activated by an environmental factor (e.g., heat, chemical composition) of a wellbore. One such alloy is Nitonol; when it is injected into the wellbore, the hot oil flow causes it to change shape. The body of the stinger 77 is attached via a structure 3, which could use a crimp or braze, to the wire 1 being fed into the wellbore. The anchor 75 can serve to both guide the wire 1 into the wellbore and to move in a chaotic motion when inside the wellbore; thus, bending, twisting, and deforming the wire 1 to initiate and enhance entanglement.
 FIGS. 10a, and 10b show a deployable stinger 80 that activates via a trigger switch 76 to deploy. The deployable stinger 80 includes two half shells 82, and 83 that can rotate about a given section 85 with the assist of a torsion spring 86. The deployment of the stinger 80 is initiated when the trigger switch 76 is pushed in when the tip 81 bangs against something such as the opposite wall of the wellbore, which moves the trigger switch 76 from the locked region 76b into the unlocked region 76a. Once triggered, the top shell 83 is caused to rotate, e.g., by the torsion spring 86, around the common center held together via a pin 84. A clearance channel 83b allows the top half to move rotate. In some embodiments, the activation of the stinger can be performed with a chemical interaction, temperature change (e.g. via Nitinol components), mechanical (as illustrated), etc.
 FIG. 10c shows the deployable stinger 80 in a deployed state 80a. The change in configuration can cause the stinger to spin, which twists the wire 1 and promotes further entanglement.
 The examples of FIGS. 9, 10, and 10b, illustrate particular implementations of a deployable stinger; i.e., a stinger which has both an undeployed state and a deployed state. The undeployed states, in general, are characterized by relatively high maneuverability and controllability, relatively low cross section, relatively low drag coefficients, etc. The deployed states, by contrast, are characterized by a relatively high propensity to undergo turbulent motion, a relatively high cross section, a relatively high drag coefficient, and more generally a relatively high tendency to promote entanglement of the wire 1 it carries.
 In practice, 12-20 gauge wire can be used as the basis for the nominal wire size, and solid wire, as opposed to stranded, is less likely to buckle in the feeding mechanism before entering the wellbore. Plane wire has relatively high friction with itself and thus entangles easily. Insulated wire packs well because the plastic insulation yields under increasing pressure to form a more solid ball. Hence one embodiment involves a wire 1 with non insulated and insulated sections, or two or more different wires such as shown in FIG. 3c, with one following the other.
 Further modifications will also occur to persons skilled in the art, and all such are deemed to fall within the spirit and scope of the invention as defined in the appended claims.
Patent applications by Alexander H. Slocum, Bow, NH US
Patent applications in class Placing or shifting well part
Patent applications in all subclasses Placing or shifting well part