US-12618729-B2 - Systems, devices and methods for monitoring support platform structural conditions

US12618729B2US 12618729 B2US12618729 B2US 12618729B2US-12618729-B2

Abstract

Systems, devices and methods enable generation and monitoring of support platform structural conditions in a manner that overcomes drawbacks associated with conventional approaches (e.g., load cells) for generating and monitoring similar operating condition information. In preferred embodiments, such systems, devices and methods utilize fiber optic strain gauges (i.e., fiber optic sensors) in place of (e.g., retrofit/data replacement) or in combination with conventional load cells. The fiber optic sensors are strategically placed at a plurality of locations on one or more support bodies of a support platform. In preferred embodiments, the fiber optic strain gauges are placed in positions within a hull and/or one or more pontoons of an offshore platform. Such positions are selected whereby resulting operating condition data generated by the fiber optic strain gauges suitably replaces data received by conventionally constructed and located load cells of an offshore platform (e.g., a TLP).

Inventors

David Verl Brower

Assignees

ASTRO TECHNOLOGY GROUP, LLC

Dates

Publication Date: 20260505
Application Date: 20241210

Claims (20)

1 . A method of instrumenting an offshore platform to enable monitoring of structural loadings required for securing the offshore platform to a seabed, comprising: one of obtaining and determining strain gauge placement information for one or more strain gauges being attached to a structural member of a structural body of the offshore platform, wherein the strain gauge placement information is a function of strain field information for loadings exerted on the structural body by a plurality of elongated seabed anchoring bodies each attached to the structural body at an exterior portion thereof and to the seabed for securing the offshore platform to the seabed, wherein the structural body includes an interior space, and wherein at least a portion of the structural member is located within the interior space; and attaching one or more strain gauges directly to a portion of the structural member located within the interior space of the structural body in accordance with the strain gauge placement information.
2 . The method of claim 1 wherein the structural member spans at least partially across the interior space of the structural body.
3 . The method of claim 2 wherein: the structural body includes a tip tank; and the structural member is located within the tip tank.
4 . The method of claim 1 wherein the placement information includes a location of the structural member at which each of the one or more strain gauges is to be attached thereto and an angular orientation of a sensing axis thereof relative to an angular orientation reference axis.
5 . The method of claim 4 wherein the placement information specifies a surface of the structural member to which each of the one or more strain gauges are attached.
6 . The method of claim 1 wherein: the strain field information identifies a plurality of strain field regions each exhibiting strain in a respective generalized direction relative to a vertical reference axis laying within a surface of the structural member; and the placement information specifies a respective one of the strain field regions within which each of the one or more strain gauges is to be attached to the respective surface with the sensing axis thereof at least approximately aligned with the respective generalized strain direction of the sensing axis.
7 . The method of claim 6 wherein the structural member spans at least partially across the interior space of the structural body.
8 . The method of claim 7 wherein: the structural body includes a tip tank; and the structural member is located within the tip tank.
9 . The method of claim 1 wherein: the placement information specifies a surface of the structural member to which at least a portion of the one or more strain gauges are attached; a vertical reference axis lies within the surface; a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis; a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
10 . An offshore platform, comprising: a structural body having exerted thereon forces generated by securing the offshore platform to the seabed by a plurality of elongated seabed anchoring bodies each attached to the structural body at an exterior portion thereof and to the seabed, wherein the structural body includes an interior space; a structural member located at least partially within the interior space of and fixedly attached to the structural body; and one or more strain gauges, wherein each of the one or more strain gauges is attached directly to the structural member on a surface thereof located within the interior space of the structural body, wherein each of the one or more strain gauges is attached in accordance with strain gauge placement information derived from strain field information within the structural member, and wherein the strain field information is a function of loadings corresponding to said forces generated by securing the offshore platform to the seabed.
11 . The offshore platform of claim 10 wherein the structural member: spans across the interior space of the structural body; and is attached at opposing end portions thereof to the structural body.
12 . The offshore platform of claim 11 wherein: the structural body includes a tip tank; and the structural member is located within the tip tank.
13 . The offshore platform of claim 10 wherein each of the one or more strain gauges is attached to a surface of the structural member within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis.
14 . The offshore platform of claim 13 wherein: a vertical reference axis lies within the surface; a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis; a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
15 . The offshore platform of claim 10 wherein: the placement information specifies a surface of the structural member to which the one or more strain gauges are attached; a vertical reference axis lies within the surface; a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis; a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
16 . The offshore platform of claim 10 wherein the placement information includes a location of the structural member at which each of the one or more strain gauges is to be attached thereto and an angular orientation of a sensing axis thereof relative to an angular orientation reference axis.
17 . The offshore platform of claim 16 wherein the structural member: spans across the interior space of the structural body; and is attached at opposing end portions thereof to the structural body.
18 . The offshore platform of claim 17 wherein: the placement information specifies a surface of the structural member to which the one or more strain gauges are attached; a vertical reference axis lies within the surface; a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis; a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.
19 . The offshore platform of claim 18 wherein each of the strain gauges is attached to the surface within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis.
20 . The offshore platform of claim 10 wherein: the placement information specifies a surface of the structural member to which at least a portion of the one or more strain gauges are attached; each of the one or more strain gauges is attached to the surface within a respective one of a plurality of strain field regions of the structural member with the sensing axis thereof at least approximately aligned with a respective generalized strain direction of the sensing axis; a vertical reference axis lies within the surface; a first one of the one or more strain gauges has the sensing axis thereof extending approximately parallel to the vertical reference axis; a second one of the one or more strain gauges has the sensing axis thereof extending approximately perpendicular to the vertical reference axis; and a third one of the one or more strain gauges has the sensing axis thereof extending at an acute angle relative to the vertical reference axis.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This continuation patent application claims priority from co-pending U.S. Non-Provisional patent application having Ser. No. 18/182,454, filed 13 Mar. 2023, entitled “SYSTEMS, DEVICES AND METHODS FOR MONITORING SUPPORT PLATFORM STRUCTURAL CONDITIONS”, which claims priority as a continuation patent application from co-pending U.S. Non-Provisional patent application having Ser. No. 17/843,805, filed 17 Jun. 2022, entitled “SYSTEMS, DEVICES AND METHODS FOR MONITORING SUPPORT PLATFORM STRUCTURAL CONDITIONS”, now U.S. Pat. No. 11,644,371, which claims priority as a continuation patent application from co-pending U.S. Non-Provisional patent application having Ser. No. 17/571,472, filed 8 Jan. 2022, entitled “SYSTEMS, DEVICES AND METHODS FOR MONITORING SUPPORT PLATFORM STRUCTURAL CONDITIONS”, now U.S. Pat. No. 11,422,047, all having a common applicant herewith and being incorporated herein in their entirety by reference. FIELD OF THE DISCLOSURE The disclosures made herein relate generally to monitoring of operating conditions of structural members and, more particularly, to systems, devices and methods for monitoring support (e.g., offshore) platform structural conditions. BACKGROUND Structural bodies for which it is necessary to monitor structural conditions thereof are well-known and are used in many industries and applications. Elongated tubular bodies (e.g., pipes) and enclosed tubular bodies (e.g., hulls and pontoons) are examples of structural bodies having with an interior space. Pipes, hulls and pontoons used in offshore drilling and production systems in the oil and gas industry are a prime example of structural bodies for which it is necessary to monitor structural conditions thereof. It is desirable if not essential to monitor parameters such as, for example, stress, strain and temperature of structural bodies, particularly in structural bodies of offshore drilling and production systems. Offshore drilling and production systems include a work platform at a sea surface (i.e., an offshore platform) that is in communication with a subsurface exploration and/or production site. The offshore platform includes a floatation structure for allowing it to float at the sea surface. Such a floatation structure is well known to often include a hull comprising an enclosed main body (e.g., a columnar shaped body) and a plurality of buoyancy tanks (e.g., pontoons) attached thereto in typically an equally-spaced manner. A tendon leg platform (TLP) is a specific example of offshore platform having a platform structure for which operating conditions need to be monitored. A TLP, which is typically a permanently positioned structure used for the production of oil and gas in offshore environments, uses a platform structure comprising tendons (i.e., also referred to as tension legs) to support platform elements above the sea surface. TLPs have recently been implemented for use as a base for offshore wind turbines. TLPs are moored to the seabed by a plurality of tendons each connected to a respective piling that has been driven into the seabed at one end and connected to a respective location of a respective buoyancy tank at the other end (e.g., respective location of a respective pontoon). The tendons of a TLP, which are typically made of tubular steel, maintain the TLP in a generally static position thanks to the balance between thrust forces due to flotation and fastening forces generated by the anchoring elements (tendons and seabed pilings). The tendons restrict vertical motion of the platform that would otherwise occur due to tides and wave action. A major advantage results for TLP structures is that an associated wellhead can be placed on the TLP platform rather than on the sea floor thereby providing better access to the wellhead and more simple production control. As is well-known, it is desirable to operate drilling and production systems in a safe, reliable, predictable and efficient manner. It is thus beneficial to monitor operating condition information of elongated tubular members of drilling and production systems, such as a TLP. To this end, in a typical TLP installation, a plurality of load cells (i.e., load sensors) are installed into a tendon top connector assembly, which is on a sub-platform or bridge for each tendon. Data from these load cells is used to monitor operating conditions in support bodies of the TLP—e.g., tendons, pontoons, hull or a combination thereof. Specific examples of operating conditions include, but are not limited to, strain and/or stress within one or more walls of a support member, pressure within an interior space of a support member, torsion applied to a support member, temperature of a wall or surface of a support member and the like. In this regard, tendon tensions provide data that enables assessment of loading condition of the TLP; measurement of horizontal center-of-gravity (“COG”) and platform weight; determination of platform locatio