Patent Application
20160160591
1. Field of the Disclosure
This disclosure relates generally to degradable slip rings and systems that utilize same for downhole applications.
2. Background of the Art
Wellbores are drilled in subsurface formations for the production of hydrocarbons (oil and gas). Hydrocarbons are trapped in various traps or zones in the subsurface formations at different depths. In many operations, such as fracturing, it is required to anchor devices (such as packers, bridge plugs, etc.) in a downhole location to facilitate production of oil and gas. After such operations, anchoring devices must be removed or destroyed before following operations can begin. Such removal operations may be costly and/or time consuming. It is desired to provide an anchoring device that can provide sufficient anchoring performance while providing desired and predictable degradation characteristics.
The disclosure herein provides controlled degradable slip rings and systems using the same for downhole applications.
In one aspect, an anchoring device is disclosed, including: a degradable substrate with a first hardness; and a plurality of gripping inserts associated with the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness.
In another aspect, a method to anchor a downhole device is disclosed, including: providing a degradable substrate with a first hardness; and inserting a plurality of gripping inserts to the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness.
In another aspect, a downhole system is disclosed, including: a casing string; and an anchoring device associated with the casing string, including: a degradable substrate with a first hardness; and a plurality of gripping inserts associated with the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness and the second hardness is greater than a hardness of an inner diameter of the casing string.
Examples of certain features of the apparatus and method disclosed herein are summarized rather broadly in order that the detailed description thereof that follows may be better understood. There are, of course, additional features of the apparatus and method disclosed hereinafter that will form the subject of the claims appended hereto.
The disclosure herein is best understood with reference to the accompanying figures, wherein like numerals have generally been assigned to like elements and in which:
In an exemplary embodiment, a wellbore 106 is drilled from a surface 102 to a downhole location 110. Casing 108 may be disposed within wellbore 106 to facilitate production. In an exemplary embodiment, casing 108 is disposed through multiple zones of production Z1 . . . Zn in a downhole location 110. Wellbore 106 may be a vertical wellbore, a horizontal wellbore, a deviated wellbore or any other suitable type of wellbore or any combination thereof.
To facilitate downhole operations, such as fracturing operations, bridge plugs 116a, packers 116b, or other suitable downhole devices are utilized within casing string 108. In certain embodiments, such downhole devices 116a,b are anchored to casing string 108 via an anchor assembly 118. In certain embodiments, bridge plugs 116a utilize an anchor assembly 118 and frac balls 120 to isolate zones Z1 . . . Zn for fracturing operations. In certain embodiments, frac balls 120 are disposed at a downhole location 110 to obstruct and seal fluid flow in local zone 112 to facilitate flow to perforations 114 in conjunction with frac plugs 116a. In certain embodiments, packers 116b are utilized in conjunction with anchor assembly 118 to isolate zones Z1 . . . Zn for fracturing operations.
In certain embodiments, frac fluid 124 is pumped from a frac fluid source 122 to a downhole location 110 to flow through perforations 114 in a zone 112 isolated by downhole device 116a,b. Advantageously, fracturing operations allow for more oil and gas available for production.
After desired operations (such as fracturing operations) and before following operations, anchoring devices 118 are often removed or otherwise destroyed to allow the flow of oil and gas through casing 108. In an exemplary embodiment, anchoring devices 118 are configured to anchor against casing 108 of local zone 112 until a predetermined time at which anchoring devices 118 dissolve or degrade to facilitate the production of oil and gas. Advantageously, in an exemplary embodiment, the anchoring devices 118 herein are formed of multiple materials to have predictable and adjustable degradation characteristics while allowing for suitable anchoring characteristics.
In an exemplary embodiment, anchor assembly 218 includes a wedge 224 and a slip ring 228. In certain embodiments, wedge 224 is forced downhole to force slip ring 228 outward against casing 208 to anchor against casing 208. In certain embodiments, slip ring 228 can crack or otherwise separate as it is driven against casing 208. In certain embodiments, wedge 224 is forced via a setting tool, explosives, or any other suitable means. In certain embodiments, downhole device 216 further utilizes a sealing member 226 to seal downhole device 216 against casing 208 and further resist movement. Sealing member 226 may similarly be driven toward casing 208 via wedge 224.
In an exemplary embodiment, a substrate of a slip ring 228 is formed of a degradable material to allow slip ring 228 to dissolve or degrade after a desired anchoring function is performed. In certain embodiments, a secondary material is used in conjunction with the substrate of the slip ring 228 to anchor the slip ring 228 against casing 208. Typically, a secondary material is harder than casing 208 to allow slip ring 228 to partially embed in casing 208. In certain embodiments, the downhole temperature exposure to downhole device 216 and slip ring 228 varies from 100 to 350 degrees Fahrenheit at a particular downhole location for a given area. Advantageously, slip ring 228 as described herein may allow for degradation after a desired time in certain downhole environments, while allowing suitable anchoring performance. In certain embodiments, portions of slip ring 228 can degrade or otherwise not prevent further downhole operations or restrict flow within a wellbore.
In an exemplary embodiment, substrate 331 is a degradable material. Advantageously, by forming substrate 331 of slip ring 328 from a degradable material, a downhole device may be anchored by slip ring 328 for the desired period of time, and then the slip ring 328 may be disintegrated to allow further operations without any obstructions. In certain embodiments, substrate 331 is formed from a corrodible metal such as a controlled electrolytic metallic, including but not limited to Intallic. Substrate 331 materials may include: a magnesium alloy, a magnesium silicon alloy, a magnesium aluminum alloy, a magnesium zinc alloy, a magnesium manganese alloy, a magnesium aluminum zinc alloy, a magnesium aluminum manganese alloy, a magnesium zinc zirconium alloy, and a magnesium rare earth element alloy. Rare earth elements may include, but is not limited to scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, and erbium. In certain embodiments, substrate materials 331 are further coated with aluminum, nickel, iron, tungsten, copper, cobalt. In certain embodiments, substrate 331 materials are consolidated and forged. In certain embodiments, the elements can be formed into a powder and a substrate can be formed form pressed powder. In an exemplary embodiment, the material of substrate 331 is selected based on desired degradation characteristics of slip ring 328.
In an exemplary embodiment, substrate 331 forms a generally cylindrical shape with an inner extent 336 and an outer extent 334. In certain embodiments, inner extent 336 has a reducing or reduced radius portion to allow a downhole device to be retained within the slip ring 328. In an exemplary embodiment, the material of substrate 331 is chosen with respect to the relative hardness of the downhole device to prevent damage to the downhole device. In an exemplary embodiment, outer extent 334 of slip ring 328 is configured to interface with a casing. In an exemplary embodiment, outer extent 334 includes inserts 330 designed to interface with casing.
In an exemplary embodiment, slip ring 328 can be configured to break in to several sections when expanded. In certain embodiments, slip ring 328 can be expanded by a wedge as previously shown in
In an exemplary embodiment, outer extent 334 includes inserts 330 configured to interface with a casing or other suitable anchor medium. In an exemplary embodiment, the material of insert 330 is selected to be harder than the interfacing casing. Casing may have a hardness of approximately 120 ksi. Casing grades may range from L80 to Q125. Advantageously, a relatively harder anchor insert 330 allows for insert 330 to firmly anchor the downhole device to casing or other suitable anchor medium. In certain embodiments, anchor insert 330 is formed of a harder material than substrate 331. Advantageously, materials, particularly degradable materials, may not have a suitable hardness to adequately anchor to a casing or other suitable anchor material, requiring the use of a harder anchor insert 330 as described herein. Materials selected for substrate 331 and insert 330 may be carefully selected to ensure insert 330 embeds further into a casing or anchor medium compared to substrate 331.
In an exemplary embodiment, inserts 330 are arranged in an ordered pattern. In other embodiments, inserts 330 are disposed in a random arrangement. In an exemplary embodiment, inserts 330 can be cubic shaped, polygonal shaped or any other geometric shape. In an exemplary embodiment, inserts 330 are configured to allow for sufficient anchoring force against an anchoring medium such as a casing. Advantageously, by utilizing granular gripping materials 330, a substrate 331 can be formed with a lower strength material to allow for greater ductility of slip ring 328. Advantageously, inserts 330 may be configured to be sized and shaped to allow passage through intended flow paths and to allow operations to continue after a substrate 331 has dissolved.
In an exemplary embodiment, inserts 330 are formed from degradable materials. Inserts 330 can be formed of any suitable material, including, but not limited to oxides, carbides, and nitrides. In certain embodiments, inserts 330 are formed from aluminum oxide, silicon carbide, tungsten carbide, zirconium dioxide, and silicon nitride. In certain embodiments, inserts 330 contain 50-90% of the previously described materials, with the balance including magnesium, aluminum, zinc, and manganese alloys.
In an exemplary embodiment, inserts 330 are disposed in receptacles 338 formed in substrate 331. During anchoring operations, inserts 330 may experience a contact pressure as inserts 330 interface with an anchor medium, such as a casing. Similarly, inserts 330 may also experience an insert pressure as inserts 330 interface with substrate 331. In certain embodiments, inserts 331 are received in receptacles 338 configured to reduce the insert pressure inserts 330 experience compared to the contact pressure inserts 330 experience as they interface with an anchor medium. In certain embodiments, receptacles 338 can offer a greater insert contact area to create a lower insert pressure compared to the contact area utilized between inserts 330 and the anchor medium.
Inserts 330 may be attached to substrate 331 via a binder or any other suitable adhesive. In certain embodiments, the binder utilizes is degradable. Binders include, but are not limited to toughened acrylics, epoxy, low metal point metals (such as aluminum, magnesium, zinc, and their alloys), etc. In other embodiments, receptacle 338 can retain inserts 330 without any additional components.
Therefore in one aspect, an anchoring device is disclosed, including: a degradable substrate with a first hardness; and a plurality of gripping inserts associated with the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness. In certain embodiments, the plurality of gripping inserts are degradable. In certain embodiments, the degradable substrate includes at least one of: a magnesium alloy, a magnesium silicon alloy, a magnesium aluminum alloy, a magnesium zinc alloy, a magnesium manganese alloy, a magnesium aluminum zinc alloy, a magnesium aluminum manganese alloy, a magnesium zinc zirconium alloy, and a magnesium rare earth element alloy. In certain embodiments, the plurality of gripping inserts includes at least one of: an oxide, a carbide, a nitride, a magnesium alloy, an aluminum alloy, a zinc alloy, and a manganese alloy. In certain embodiments, the plurality of gripping inserts are smaller than an intended flow path. In certain embodiments, further including a plurality of receptacles associated with the plurality of gripping inserts to transmit an insert pressure, wherein the insert pressure less than a contact pressure. In certain embodiments, the plurality of gripping inserts are ordered. In certain embodiments, the degradable substrate includes at least one crack initiation point. In certain embodiments, further including a binder associated with the plurality of gripping inserts and the degradable substrate. In certain embodiments, the binder is degradable. In certain embodiments, the plurality of gripping inserts comprise at least one of cubic gripping inserts and polygonal gripping inserts.
In another aspect, a method to anchor a downhole device is disclosed, including: providing a degradable substrate with a first hardness; and inserting a plurality of gripping inserts to the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness. In certain embodiments, the plurality of gripping inserts are degradable. In certain embodiments, the degradable substrate includes at least one of: a magnesium alloy, a magnesium silicon alloy, a magnesium aluminum alloy, a magnesium zinc alloy, a magnesium manganese alloy, a magnesium aluminum zinc alloy, a magnesium aluminum manganese alloy, a magnesium zinc zirconium alloy, and a magnesium rare earth element alloy. In certain embodiments, the plurality of gripping inserts includes at least one of: an oxide, a carbide, a nitride, a magnesium alloy, an aluminum alloy, a zinc alloy, and a manganese alloy. In certain embodiments, the plurality of gripping inserts are smaller than an intended flow path.
In another aspect, a downhole system is disclosed, including: a casing string; and an anchoring device associated with the casing string, including: a degradable substrate with a first hardness; and a plurality of gripping inserts associated with the outer extent of the degradable substrate, wherein the plurality of gripping inserts have a second hardness greater than the first hardness and the second hardness is greater than a hardness of an inner diameter of the casing string. In certain embodiments, the plurality of gripping inserts are degradable. In certain embodiments, the anchoring device is associated with a packer or a bridge plug. In certain embodiments, the anchoring device is associated with a wedge.
The foregoing disclosure is directed to certain specific embodiments for ease of explanation. Various changes and modifications to such embodiments, however, will be apparent to those skilled in the art. It is intended that all such changes and modifications within the scope and spirit of the appended claims be embraced by the disclosure herein.
