Internal Inspection System for Drilling Riser

Description

1 / 7 Internal Inspection System for Drilling Risers - Field of Application

[0001] This descriptive report concerns a patent for an invention relating to an "in situ" internal inspection system for drilling risers, eliminating the need to remove the riser floats, and operating on the platform deck with the risers in place. SUMMARY OF THE INVENTION

[0002] The proposed solution consists of a robot that travels internally within the riser, carrying an array of high-frequency ultrasound transducers. To ensure proper coupling of the transducers, the tool has two sets of membranes that confine water between them, the outer surface of the block containing the transducers, and the inner surface of the riser, flooding the transducer area. These membrane sets, together, have a thickness that, in addition to sealing the confined water, reduces friction of the tool inside the riser, allowing for smooth movement of the tool, which, in one pass, cleans and inspects the riser.

[0003] The tool is placed in cassettes, aligned with the riser to be inspected, having, on one side, the tool launching cassette, and, on the other side, the tool receiving cassette, having coupled, to the flange of said receiving cassette, the winch that pulls the tool. BACKGROUND OF THE INVENTION

[0004] The drilling riser is an essential component used in drilling oil and gas wells in deep and ultra-deep waters, and consists of a pipe Petition 870250014118, dated 20 / 02 / 2025, page 10 / 20 A 2 / 7 diameter pipe that connects the drilling platform, or drillship, to the well on the seabed, allowing the circulation of drilling fluids and the movement of tools between the surface and the bottom of the well.

[0005] The drilling riser is used to create a continuous connection between the platform and the seabed, enabling the circulation of drilling fluid, the return of cuttings generated by the drill bit, and the control of well pressure. It is installed along the drill string and usually has a flotation system to reduce its apparent weight in the water.

[0006] The drilling riser allows the circulation of drilling fluid, which is pumped through the drill string to the drill bit and returns through the annular space of the riser, carrying drilling debris. To ensure safety and well control, it has valves to direct unexpected fluids that may come from the well, helping to contain any uncontrolled flows. It also serves as a conduit for downhole tools and equipment, and control systems, facilitating the conduction of well returns to the surface, such as cuttings and well fluids, which return through the tubing to be processed on the platform.

[0007] Conventional drilling risers are used in shallow and medium-depth waters, while buoyancy risers are used in deep and ultra-deep waters, where the weight of the riser needs to be compensated for, avoiding overloading the platform structure. In addition, drilling risers typically have a Petition 870250014118, dated 20 / 02 / 2025, page 11 / 20 3 / 7 flexible connector at the base, to handle platform movements due to waves and sea currents.

[0008] Cleaning and inspecting the drilling riser are essential procedures to ensure safety, structural integrity, and operational efficiency during offshore oil and gas well drilling. They are fundamental to preventing failures that can lead to leaks, loss of well control, or environmental accidents. These procedures aim to remove drilling fluid residue, cuttings, and debris that can accumulate inside the riser over time, reducing its circulation capacity and compromising its efficiency. They also inhibit corrosion and scale formation processes favored by the marine environment, affecting its lifespan, reducing the risk of contamination generated by drilling multiple wells, and ensuring that fluid residues or contaminants are not transferred from one well to another, which could compromise the quality of the drilling fluid or cause undesirable chemical reactions.

[0009] The drilling riser operates under high pressure and is subject to intense mechanical forces, as well as being exposed to the harsh marine environment. Inspection helps identify cracks, corrosion, and other structural damage before they become critical, especially the riser's joints and connections, which need to be checked regularly to prevent leaks that could compromise the safety of the operation. Furthermore, the oil and gas industry follows strict safety standards that dictate that the drilling riser must meet the required specifications, since any failure in the drilling riser can lead to... Petition 870250014118, dated 20 / 02 / 2025, page 12 / 20 4 / 7 hydrocarbon spills, with significant environmental and financial impacts, are minimized by regular inspections.

[0010] The usual cleaning and inspection methods are: Hydroblasting and chemical products to remove internal deposits and residues; Pressure tests and non-destructive testing (NDT) to assess material integrity; Monitoring with sensors to track wear in real time, and visual and ultrasonic inspection to identify corrosion and cracks in the structure.

[0011] Several internal riser inspection systems are already known in the current state of the art, such as, for example, the one described in patent document BR0504987-3, which deals with an internal riser pipe inspection system that uses TOFD technique, which requires one transducer that emits and another transducer to receive the diffracted ultrasonic wave, employing only a pair of TOFD transducers that orbit the weld, and a plurality of fixed sensors, such that, upon reaching the weld inspection location, the vertical movement along the geometric axis of the drill riser pipe stops and, subsequently, the transducers are rotated, inspecting only the volume of the welds.

[0012] The solution proposed in patent document BR0503840-5 is applied to vertically arranged risers, and not to ship-laid risers, which is the most common situation found on platforms, and which guarantees safer operation; in addition, the inspection tool is gravity-launched and uses seawater as an ultrasound coupling agent. Petition 870250014118, dated 20 / 02 / 2025, page 13 / 20 5 / 7 FUNDAMENTALS OF THE INVENTION

[0013] In order to overcome the limitations of current techniques, a solution is proposed for internal inspection of drilling risers that uses a plurality of rotating transducers to inspect the welds and the body of the drilling riser, using confined water feed between the tool's sealing membranes, configuring a compact and lightweight tool, capable of being handled by a single operator, with electronics, with 16, 64, 128 or 256 channels, embedded inside a sealed vessel in the flooded measurement region, contributing to a compact and lightweight equipment, having sealing seals, formed by front and rear sets of membranes that confine water between them, the external surface of the transducer block and the internal surface of the riser, for ultrasonic inspection, cleaning the internal surface of the riser and reducing the friction of the tool during its longitudinal movement inside the riser, in a single pass.Featuring launching and receiving cassettes (tube sleeves), which allow for greater speed in launching and receiving the tool, aided by a traction winch fixed to said receiving cassette, which is easy to remove, speeding up its reinstallation on the next riser. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a better understanding of the proposed internal inspection system for drilling risers, reference is made to the attached drawings, so that its functionality can be characterized; however, the figures are merely illustrative and may vary, provided that they do not deviate from the proposed functional principle, and where: Petition 870250014118, dated 20 / 02 / 2025, page 14 / 20 6 / 7 Figure 1 illustrates an exploded perspective view of the internal inspection tool for a drilling riser according to the present invention; Figure 2 illustrates a perspective view of the internal inspection tool for a drilling riser according to the present invention; Figure 3 illustrates a perspective view opposite to that of Figure 2; Figure 4 - illustrates a perspective view of the assembly of the internal inspection system for a drilling riser according to the present invention. PREFERRED DESCRIPTION OF THE INVENTION

[0015] As illustrated in the attached figures, the proposed internal inspection system for drilling risers employs an inspection tool (1) having a front centering disc (2) equipped with front casters (3), to which is attached a set of three front membranes (4), which receive a front bearing (5) for rotation of said set of front membranes, together with the central body (6) in which the transducers (T) are installed, having, at its opposite end, a rear bearing (7) for rotation of the set of three rear membranes (8), having fixed to said rear bearing a rear centering cage (9), equipped with upper and lower casters (10), and which houses inside the rotation drive system (11), also having, on the rear surface of said cage, an inlet (12) for connection of a hose (not illustrated), for injecting water into the tool, which will be confined between the sets of front and rear membranes,the outer surface of the central body, where the transducers are installed, and, Petition 870250014118, dated 20 / 02 / 2025, page 15 / 20 7 / 7 the inner surface of the riser, with the thicknesses of the membrane assemblies being adequate to maintain the water seal in this confined space, allowing the tool, in a single pass, to perform the ultrasonic inspection, while cleaning the inner surface of the riser, without interfering with the longitudinal movement of the tool inside the riser, having launching (13) and receiving (14) cassettes (sleeve tube), and a traction winch (15), fixed to the receiving cassette, which is easy to remove for reinstallation on the next riser to be inspected. Petition 870250014118, dated 20 / 02 / 2025, page 16 / 20

Claims

1 / 1 CLAIMS 1. INTERNAL INSPECTION SYSTEM FOR DRILLING RISER employing an inspection tool (1), characterized by comprising a front centering disc (2), equipped with front casters (3), to which is coupled a set of three front membranes (4), which receive a front bearing (5) for rotation of said set of front membranes, together with the central body (6) in which the transducers (T) are installed, having, at its opposite end, a rear bearing (7) for rotation of the set of three rear membranes (8), having fixed, in said rear bearing, a rear centering cage (9), equipped with upper and lower casters (10), and which houses inside the rotation drive system (11), also having, on the rear surface of said cage, an inlet (12) for connection of a hose, for injecting water into the tool, which will be confined between the sets of front and rear membranes, the outer surface of the central body,where the transducers are installed, and the inner surface of the riser, also featuring launch (13) and reception (14) cassettes, and a traction winch (15) fixed to the reception cassette.

2. SYSTEM, according to claim 1, characterized in that the thicknesses of the membrane assemblies are adequate to maintain the water seal in the confinement space, so that the tool, in a single pass, performs the ultrasonic inspection and cleaning of the inner surface of the riser, without interfering with its longitudinal displacement inside the riser. Petition 870250014118, dated 20 / 02 / 2025, p. 17 / 20

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