# US 2020/0399962 A1 · Systems for securing bend stiffeners to riser systems in offshore energy production facilities > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0399962 A1 - Document ID: US20200399962A1 - Status: Published application - Kind: A1 - Application number: 16/445,360 - Filed: 2019-06-19 - Published: 2020-12-24 - Earliest claimed: 2019-06-19 - Assignees: Chevron U.S.A. Inc. - Applicants: Chevron U.S.A. Inc. - Inventors: Antonio C.F. CRITSINELIS; Farzan PARSINEJAD; Matthew Davis HENSE; Gary Anthony GIORDANO - Web page: https://patentgrep.com/patent/US20200399962A1 ## CPC - E21B 17/017: {Bend restrictors for limiting stress on risers} - F16G 11/04: with wedging action, e.g. friction clamps (F16G11/02, {F16G11/10} take precedence; {eyes for grommet-thimble type fastenings F16G11/146}) - F16M 13/02: for supporting on, or attaching to, an object, e.g. tree, gate, window-frame, cycle - H01F 1/055: and magnetic transition metals, e.g. SmCo5 - H01F 7/0263: {Closures, bags, bands, engagement devices with male and female parts} - H02G 1/10: in or under water - H02G 9/02: laid directly in or on the ground, river-bed or sea-bottom; Coverings therefor, e.g. tile - H02G 9/12: supported on or from floats, e.g. in water - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - F16G: BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR - F16M: FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - H02G: INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES ## Abstract Disclosed are systems for securing a bend stiffener to a riser in an offshore energy production facility. In one system, the lower end of the bend stiffener has a magnet that repels a magnet in a clamp on the riser a distance below the bend stiffener. The magnets repel one another with a force during operation to decelerate falling and prevent contact between the clamp and the bend stiffener. Methods are provided for retrofitting a riser system by adding the magnets. In another system, the riser has an upper portion and a tapered portion immediately below the upper portion. The outer diameter of the tapered portion increases such that the tapered portion can be friction fit into the lower end of the bend stiffener in the event that the bend stiffener is forced down or free falls onto the riser. ## Claims ### Claim 1 A system for securing a bend stiffener to a riser system connected to an offshore structure in an offshore energy production facility, the system comprising: a. a bend stiffener adapted to circumferentially surround a riser for protecting an upper portion of the riser from fatigue during operation of the system, the bend stiffener having an upper end proximate an upper end of the riser and a lower end, the lower end comprising a first magnetic material having magnetic properties; and b. a clamp adapted to circumferentially surround an outer surface of the riser a distance below the bend stiffener, the clamp having an upper end comprising a second magnetic material having magnetic properties opposing the magnetic properties of the first magnetic material such that the upper end of the clamp and the lower end of the bend stiffener repel one another with a repulsion force during operation of the system to decelerate falling and prevent contact between the upper end of the clamp and the lower end of the bend stiffener. ### Claim 2 (depends on 1) The system of claim 1 wherein the first magnetic material and the second magnetic material comprise a samarium-cobalt magnet. ### Claim 3 (depends on 1) The system of claim 1 wherein the first magnetic material and the second magnetic material are in the form of a first cylindrical component attachable to a tip of the bend stiffener and a second cylindrical component, respectively, wherein the second cylindrical component has an inner diameter and an outer diameter, and the inner diameter of the second cylindrical component is greater than an outer diameter of the riser to permit sufficient clearance for installation around the riser, and a distance between the inner diameter and the outer diameter of the second cylindrical component is from 1 to 10 inches. ### Claim 4 (depends on 3) The system of claim 3 wherein the first cylindrical component comprises bolt holes there through so that the first cylindrical component is attachable to the tip of the bend stiffener using bolts. ### Claim 5 (depends on 3) The system of claim 3 further comprising a cylindrical wedge component for fitting around the tip of the bend stiffener, a threaded connector for fitting around the cylindrical wedge component and a threaded nut for fitting around the threaded connector, wherein the first cylindrical component is attachable to the threaded connector using bolts or welding, such that when installed the threaded nut applies mechanical pressure to the threaded connector and the cylindrical wedge component, thereby attaching the first cylindrical component to the tip of the bend stiffener. ### Claim 6 (depends on 3) The system of claim 3 wherein, when the clamp is installed and tightened around the outer surface of the riser, friction between an inner surface of the clamp and the outer surface of the riser enables the clamp to support an impact load of up to 5 tons. ### Claim 7 (depends on 1) The system of claim 1 further comprising a removeable shielding layer for eliminating the repulsion force between the upper end of the clamp and the lower end of the bend stiffener prior to and during assembly of the bend stiffener and the clamp, wherein the shielding layer can be removed for establishing the repulsion forces during installation and/or operation of the system. ### Claim 8 (depends on 7) The system of claim 7 wherein the removeable shielding layer is a cylindrical insert comprising a ferrite compound material comprising iron. ### Claim 9 (depends on 8) The system of claim 8 wherein the removeable shielding layer has a thickness of from 1 to 10 inches. ### Claim 10 A system for securing a bend stiffener to a riser system connected to an offshore structure in an offshore energy production facility, the system comprising: a. a bend stiffener adapted to circumferentially surround a riser and a circumferential gap around the riser, the bend stiffener having an upper end and a lower end; and b. the riser having an upper end having a first outer diameter less than an inner diameter of the lower end of the bend stiffener; wherein the riser comprises an upper portion having a first outer diameter and an upper portion length, and a tapered portion immediately below the upper portion having a tapered portion length wherein the tapered portion has an outer diameter that gradually increases from the first outer diameter to a second outer diameter, such that the tapered portion can be friction fit into the lower end of the bend stiffener in the event that the bend stiffener is forced down or free falls onto the riser. ### Claim 11 (depends on 10) The system of claim 10 wherein the tapered portion comprises an outer layer extruded onto the riser. ### Claim 12 (depends on 11) The system of claim 11 wherein the gradually increasing outer diameter of the tapered portion is formed by machining the extruded outer layer. ### Claim 13 (depends on 10) The system of claim 10 wherein the tapered portion comprises an outer layer glued onto the riser. ### Claim 14 (depends on 10) The system of claim 10 wherein the tapered portion comprises an outer layer clamped onto the riser. ### Claim 15 (depends on 10) The system of claim 10 wherein the tapered portion comprises an outer layer comprising a tape layer wrapped onto the riser. ### Claim 16 (depends on 10) The system of claim 10 wherein the riser comprises a multilayer flexible pipe riser having multiple layers including an outer protective layer, at least one insulation layer, an intermediate plastic layer, and metal elements wherein the intermediate plastic layer surrounds the metal elements, and wherein the upper portion comprises all of the multiple layers with the exception of the outer protective layer and at least one insulation layer, and the tapered portion comprises all of the multiple layers. ### Claim 17 (depends on 10) The system of claim 10 wherein the riser further comprises a lower portion immediately below the tapered portion having the second outer diameter and extending at least a portion of a length of the riser below the tapered portion. ### Claim 18 (depends on 1, 10) The system of claim 1 or 10, further comprising a bend stiffener connector attached to the upper end of the bend stiffener wherein the bend stiffener connector comprises a mechanism for mating to a facility hang off interface; and a topside end fitting attached to the bend stiffener connector for attaching to a pull wire and for releasing the riser once the bend stiffener is connected to the facility hang off interface. ### Claim 19 (depends on 1, 10) The system of claim 1 or 10 wherein the offshore energy production facility is a subsea oil and gas and energy production or an offshore wind farm. ### Claim 20 (depends on 1, 10) The system of claim 1 or 10 wherein the riser contains a conduit for fluid or a power cable. ### Claim 21 A method for retrofitting a riser system connected to an offshore structure in an offshore energy production facility, the method comprising: a. adding a first material having magnetic properties into a lower end of an existing installed bend stiffener circumferentially surrounding a riser for protecting an upper portion of the riser from fatigue during operation of the system; and b. adding a second material having magnetic properties opposing the magnetic properties of the first material into an upper end of an existing installed clamp circumferentially surrounding the riser a distance below the bend stiffener, such that the upper end of the clamp and the lower end of the bend stiffener repel one another with a repulsion force during operation of the system to prevent contact between the upper end of the clamp and the lower end of the bend stiffener. ### Claim 22 (depends on 28) The method of claim 28 further comprising placing a removeable shielding layer for eliminating the repulsion force between the upper end of the first material and the lower end of the bend stiffener prior to the addition of the first material and the second material, and removing the removeable shielding layer after the addition of the first material and the second material.