System and method for blockage removal, cleaning and monitoring pressures in subsea equipment

Abstract

The present invention is within the field of technologies for blockage removal, cleaning and pressure monitoring of subsea equipment used in the oil and gas industry, and relates to a system for blockage removal, cleaning and pressure monitoring of subsea equipment comprising: an intake vertical connection mandrel (VCM) (2); a discharge VCM (3); at least one supply umbilical (10) connected to a manifold (1); a first short flexible jumper (400) for interconnecting an intake line of the manifold (1) to a flushing panel (17); a second short flexible jumper (500) for interconnecting a discharge line of the manifold (1) to the flushing panel (17); a first long flexible jumper (11) connected to the flushing panel (17) for the intake line; a second long flexible jumper (12) connected to the flushing panel (17) for the discharge line; wherein the manifold (1) is connected to a Side Entry Sub (SES) (13) of a drill pipe riser (DPR) (14); wherein each VCM from the intake VCM (2) and the discharge VCM (3) has a blind flange (20, 30), a panel support (21, 31) and a jumper interface panel (22, 32) mounted on the panel support (21, 31). The present invention further relates to a method of blockage removal, cleaning and monitoring pressures of subsea equipment.

Description

FIELD OF THE INVENTION

[0001] The present invention is within the technical field of technologies for blockage removal, cleaning and monitoring pressures in subsea equipment used in the oil and gas industry, and, more particularly, it refers to a system and a method that use vertical connection mandrels to perform wells interventions in which the fluid circulation lines are disconnected from a production adapter base (PAB) or a subsea pumping module (MOBO). Furthermore, when used in a PAB whose lines are disconnected, the present invention enables accessories and / or sensors to perform direct shut-in readings in cases where signals are unavailable from sensors from the wet Christmas tree (WCT) (temperature and pressure transducer—TPT and pressure transducer—PT), from the well (permanent downhole gauge—PDG) or even the absence of an annulus sensor.BACKGROUND OF THE INVENTION

[0002] There are instances where wells are temporarily abandoned (wells with lines disconnected from the stationary production unit—SPU). In such cases, disconnection of the lines from the PAB results in loss of the chance to monitor the well pressures, and monitoring is then carried out through vessel visits to read the sensors, provided that such vessels are available. Nevertheless, this is considered a passive approach, as there is no interaction with the well and it is possible to take actions to mitigate risks (well cushioning).

[0003] As long as the shut-in well pressures are within the equipment specified thresholds, monitoring by vessels is deemed valid. However, when pressures approach safe and calculated thresholds, the emergency deployment of a probe is required to be connected to the well and perform a direct intervention in the well.

[0004] Moreover, some wells have an artificial lift system through the installation of pumps on the seabed—submerged centrifugal pumping (SCP). Among the types of pumps available for use in a vertical lift system is the pumping module (MOBO), wherein a pump is placed in a “false well”, the natural-flow well going to the seafloor to produce up to the wet Christmas tree (WCT), and, through a flexible jumper, the product flows to a system composed of a pumping adapter base and a pumping module (PAB-MOBO), from which it is pumped to the production unit (SPU).

[0005] At the MOBO, the well may be abandoned, the lines cleaned and disconnected, without the MOBO capsule being cleaned due to MOBO blockage (hydrate formation). In such instances, it is risky to raise the MOBO assembly without breaking the hydrate formed, basically for two reasons:—depressurization of the MOBO during ascent, which may lead to product leakage into the environment; and—operation with pressurized systems with surface hydrocarbons (demobilization).

[0006] In scenarios involving abandoned and disconnected wells, integrity and pressure monitoring is performed through vessel sporadic visits, during which the vessel uses reading equipment (SASMIC, DATA IWIS) to take spot / historical pressure / temperature readings of production wellbore and annulus. In addition to being a passive monitoring, they depend on the operation / calibration of sensors installed at the WCT (TPT / PT) and at the production / injection string (PDG). If the sensors are lost or absent, the data cannot be read.

[0007] Therefore, there is a need for a system and a method capable of properly and safely remove blockage and clean subsea equipment in intervention operations in wells whose lines are disconnected from a PAB or MOBO. Furthermore, this solution must also provide a structure enabling the installation of additional accessories (e.g., sensors, battery banks), ensuring direct access to the well through both bores.STATE OF THE ART

[0008] The state of the art includes some documents that disclose subject matter that is within the same technological field as the present invention.

[0009] U.S. Pat. No. 9,797,223B1 discloses a method for treating the formation of hydrates in a fluid system including: pumping a fluid at a substantially constant fluid flow rate through a hydrate removal system including a pressure modulator, communicating a vacuum pressure to a piece of subsea equipment from a pressure port of the pressure modulator, closing a valve in the hydrate removal system to cease the fluid flow through the hydrate removal system at the substantially constant fluid flow rate, and communicating a positive pressure greater than the vacuum pressure to the piece of subsea equipment in response to closing the valve of the hydrate removal system.

[0010] The method disclosed by document U.S. Pat. No. 9,797,223B1 is interconnected with a system for hydrate removal at a subsea site. In the solution proposed by the aforementioned document, vacuum is communicated to the piece of subsea equipment from a pressure port of a pressure modulator. During hydrate removal, a surface vessel is connected to and operates a subsea skid that provides vacuum. Furthermore, the subsea skid has a storage tank into which dissolved hydrate flows. In this solution, a hydraulic piston is moved to provide the vacuum. However, document U.S. Pat. No. 9,797,223B1 fails to disclose or suggest a system containing two vertical connection mandrels (VCMs), one for intake and one for discharge, to circulate a gas (N2) through the interior of a pumping module, the VCMs comprising support structures to support a panel with a receptacle; and umbilicals from the Drill Pipe Riser (DPR), which are connected to a manifold to vent the gas to the VCMs, as in the present invention.

[0011] In turn, document WO2022235165A1 discloses a subsea hydrate removal assembly configured for removal of hydrate inside subsea equipment, wherein the subsea hydrate removal assembly comprises a tank at a subsea location. The pressure inside the tank is lower than the pressure at the location of the hydrate inside the subsea equipment. A fluid jumper has a wet-mate connection at a first end and / or at a second end. The fluid jumper constitutes at least part of a fluid flow path that connects the tank and the subsea equipment, thereby enabling fluid communication between the interior of the tank and the hydrate inside the subsea equipment. The subsea hydrate removal assembly is autonomous. A method and a hydrate dissolving tank are also disclosed.

[0012] However, the system disclosed in document WO2022235165A1 proposes that a tank be installed on the seabed close to the hydrate-forming equipment, and that, by means of a jumper, it performs fluid exchange with the subsea equipment to dissolve the hydrate formed.

[0013] Both systems (U.S. Pat. No. 9,797,223B1 and WO2022235165A1) are methods for providing hydrate breakdown but have volumetric limitations and do not contemplate the circulation of different fluids (N2, diesel, inhibited fluid or seawater) after hydrate breakdown to provide cleaning and compliance of the subsea system. In contrast, the present invention discloses a system using two VCMs, each provided with a panel featuring a receptacle (flushing panel), for connecting jumpers from a manifold that is directly connected to the Side Entry Sub (SES) of the DPR column, in order to circulate N2 within a MOBO and thereby promote hydrate break down (blockage removal) and subsequent cleaning of the equipment for future retrieval.BRIEF DESCRIPTION OF THE INVENTION

[0014] The present invention relates to a system and method for blockage removal and cleaning subsea equipment using modified vertical connection mandrels to create a circulation line for venting a gas (N2) to breakdown hydrate that is blocking a pumping module (MOBO) or a production adapter base (PAB). After gas venting, fluids (diesel and water) can be circulated through the interior of the subsea equipment—previously obstructed by the hydrate formation—via an umbilical (preferably a high collapse resistant—HCR—umbilical) and returning through the DPR column for cleaning and preparation of the subsea equipment for future retrieval.

[0015] By implementing the system and method of the present invention, it is possible to break down the hydrate and pump fluid to cushion a well safely and efficiently causing the fluid to circulate and clean the subsea equipment in its demobilization process for future retrieval. Furthermore, the system and method of the present invention can also perform pressure monitoring of subsea equipment.

[0016] Thus, the advantages and objectives of the present invention are achieved by providing a system for blockage removal, cleaning and monitoring pressures of subsea equipment, which comprises:—an intake vertical connection mandrel (VCM);

[0017] a discharge VCM;

[0018] at least one supply umbilical connected to a manifold;

[0019] a first short flexible jumper for interconnecting an intake line from the manifold to a flushing panel;

[0020] a second short flexible jumper for interconnecting a discharge line from the manifold to the flushing panel;

[0021] a first long flexible jumper connected to the flushing panel for the intake line;

[0022] a second long flexible jumper connected to the flushing panel for the discharge line;

[0023] wherein the manifold is connected to a Side Entry Sub (SES) of a Drill Pipe Riser (DPR);

[0024] wherein each VCM from the intake VCM and discharge VCM has a blind flange, a panel support, and a jumper interface panel mounted on the panel support;

[0025] the jumper interface panel of the intake VCM comprising a hot stab receptacle installed thereon, wherein a third jumper connects the receptacle to an inlet of the intake VCM through the blind flange;

[0026] the jumper interface panel of the discharge VCM comprising a hot stab receptacle installed thereon, wherein a fourth jumper connects the receptacle to an inlet of the discharge VCM through the blind flange;

[0027] wherein each of the first and second long flexible jumpers is provided with a hot stab at its end for connection to the respective VCM receptacles.

[0028] Furthermore, the present invention includes a method of blockage removal, cleaning and monitoring the pressures of subsea equipment, which comprises:-installing an intake vertical connection mandrel (VCM) onto a first mandrel of a pumping adapter base (PAB), and a discharge VCM onto a second mandrel of the PAB;

[0029] deploying a Drill Pipe Riser (DPR) toward a subsea equipment installed on the PAB, the DPR further comprising at least one supply umbilical, a manifold having the at least one supply umbilical and the first and second long flexible jumpers connected thereto, and the SES having the manifold connected thereto;

[0030] connecting a hot stab of the first long flexible jumper to a receptacle of the intake VCM, and a hot stab of the second long flexible connector pipe to a receptacle of the discharge VCM;

[0031] venting a gaseous fluid from the at least one supply umbilical and the manifold toward the intake VCM via the first long flexible jumper and into the subsea equipment;

[0032] circulating diesel from the at least one supply umbilical and the manifold toward the intake VCM and into the subsea equipment; and

[0033] returning the diesel circulated through the interior of the subsea equipment via the discharge VCM and into the DPR riser.

[0034] Finally, when used in abandoned / disconnected wells, the proposed system will allow remote pressure and temperature measurement accessories (SASMIC, DATA IWIS) to have direct access to the production bore and the annulus bore in instances where the sensors present in the WCT or in the well are not operational. Although the discharge_VCM panel has a pressure gauge, in these cases, instead of connecting the MOBO cleaning jumper, connecting these data acquisition devices and taking a direct reading of the shut in (production discharge_VCM) or annular pressure (annular discharge_VCM). For this purpose, it would be sufficient for an acquisition vessel to connect the reader via hot stab, open the PAB (AI's) and WCT (Master, Wing) valves.BRIEF DESCRIPTION OF THE FIGURES

[0035] The preferred embodiments of the present invention will be better understood when read in conjunction with the accompanying drawings. It must be understood, however, that the present invention is not limited merely to the precise arrangements and instruments shown.

[0036] Accordingly, the present invention will now be described with reference to its typical embodiments and to the accompanying drawings, in which:

[0037] FIG. 1A shows a schematic view of a system for blockage removal, cleaning and monitoring pressures of subsea equipment, in accordance with an embodiment of the present invention.

[0038] FIG. 1B shows an enlarged schematic view of a manifold of the system for blockage removal, cleaning and pressure monitoring of subsea equipment, which is designated as “manifold”. Such manifold consists of a solid block that will be hung on the SES. Through-holes will be machined in the block to connect the lines of the two HCR umbilicals and an outlet to the SES and providing access to the DPR riser in accordance with one embodiment of the present invention.

[0039] FIG. 1C shows an enlarged schematic view of an intake vertical connection mandrel of the system for blockage removal, cleaning and monitoring pressures of subsea equipment, according to one embodiment of the present invention.

[0040] FIG. 1D shows an enlarged schematic view of an discharge vertical connection mandrel of the system for blockage removal, cleaning and monitoring pressures of subsea equipment, according to one embodiment of the present invention.

[0041] FIG. 1E shows an enlarged schematic view of the flushing panel, from which the intake and discharge jumpers will be connected and laid out. The ends of these jumpers with hot stabs will be placed in the receptacle (parking place) to protect them during maneuvers.

[0042] FIG. 2A shows a simplified schematic view of a system for blockage removal, cleaning and monitoring pressures of subsea equipment, in accordance with an embodiment of the present invention.

[0043] FIG. 2B shows the circulation circuit and the (intake / discharge) lines with the hydraulic diagram, according to one embodiment of the present invention.

[0044] FIG. 3A shows an isometric perspective view of an intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0045] FIG. 3B shows an enlarged view of an adapter and support assembly region on a blind flange of the intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0046] FIG. 3C shows an enlarged view of a connection panel, adapter and support assembly region on a blind flange of the intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0047] FIG. 3D shows an enlarged view of the intake vertical connection mandrel panel, in accordance with one embodiment of the present invention.

[0048] FIG. 3E shows an enlarged view of a counterweight assembly suspended by the intake vertical connection mandrel adapter, in accordance with one embodiment of the present invention.

[0049] FIG. 3F shows an enlarged view of a third connector pipe connecting a receptacle to a blind flange of the intake vertical connection mandrel, with the connection panel being omitted, in accordance with one embodiment of the present invention.

[0050] FIG. 4A shows an isometric perspective view of a discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0051] FIG. 4B shows an enlarged view of an adapter and support assembly region on a blind flange of the discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0052] FIG. 4C shows an enlarged view of a connection panel, adapter and support assembly region on a blind flange of the discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0053] FIG. 4D shows an enlarged view of the discharge vertical connection mandrel panel, in accordance with one embodiment of the present invention.

[0054] FIG. 4E shows an enlarged view of a counterweight assembly suspended by the discharge vertical connection mandrel adapter, in accordance with one embodiment of the present invention.

[0055] FIG. 4F shows an enlarged view of a fourth connector pipe connecting a receptacle to a blind flange of the discharge vertical connection mandrel, with the connection panel being omitted, in accordance with one embodiment of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0056] Below, reference is made in detail to the preferred embodiments of the present invention illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers shall be used throughout the drawings to make reference to the same or similar features. It should be noted that the drawings are simplified and are not represented to a precise scale, so slight variations are anticipated.

[0057] The present invention relates to systems and methods that use vertical connection mandrels mounted on a pumping adapter base (PAB) to perform blockage removal (hydrate breakdown) and cleaning inside a subsea equipment (such as a MOBO or PAB, for example), by circulating fluid from a borehole to another, wherein each vertical connection mandrel has a line assembly specially adapted to perform ventilation and fluid circulation. After venting a gas, fluids (diesel and water) may be circulated inside the subsea equipment through an HCR umbilical and such fluids may return through the Drill Pipe Riser (DPR) for cleaning and preparation for future retrieval of the subsea equipment.

[0058] The description of the present invention will be made below primarily based on the system, only for ease of reference and understanding of the present invention. Nevertheless, the steps of the method associated with the system will be evident to a person skilled in the art, from reading the technical features relative to the system of the present invention. In addition, since the present invention provides direct access to the bores (production / annulus), all the features and changes of VCMs can be used in the embodiment of monitoring disconnected abandoned wells, simply by installing the discharge VCMs directly in the PAB and carrying out valve maneuvers. To this end, pressure measuring devices (SASMIC, DATA IWIS) will be connected to the panel hot stab.

[0059] Thus, reference is made to FIGS. 1A, 1B, 1C, 1D, 1E, 2A and 2B, which show, in general, a system for blockage removal, cleaning and monitoring pressures of subsea equipment, containing its main components, in accordance with one embodiment of the present invention. In one embodiment of the present invention, the system comprises:-an intake vertical connection mandrel (VCM) 2;

[0060] a discharge vertical connection mandrel (VCM) 3;

[0061] at least one supply umbilical 10 connected to a manifold 1;

[0062] a first short flexible jumper (mini jumper HCR) 400 for interconnecting an intake line of the manifold 1 to a flushing panel 17;

[0063] a second short flexible jumper (mini HCR jumper) 500 for interconnecting a discharge line of the manifold 1 to the flushing panel 17;

[0064] a first long flexible jumper 11 connected to the flushing panel 17 for the intake line;

[0065] a second long flexible jumper 12 connected to the flushing panel 17 for the discharge line;

[0066] wherein the manifold 1 is connected to a Side Entry Sub (SES) 13 of a Drill Pipe Riser (DPR) 14;

[0067] wherein each VCM—the intake VCM 2 and the discharge VCM 3—comprises a blind flange 20, 30, a panel support 21, 31, and a jumper interface panel 22, 32 mounted on the panel support 21, 31;

[0068] the jumper interface panel 22 of the intake VCM 2 comprising a hot stab receptacle 221 mounted thereon, a third jumper 222 connecting the receptacle 221 to the inlet of the intake VCM 2 through the blind flange 20;

[0069] the jumper interface panel 32 of the discharge VCM 3 comprising a hot stab receptacle 321 mounted thereon, a fourth jumper 322 connecting the receptacle 321 to the inlet of the discharge VCM 3 through the blind flange 30;

[0070] wherein each of the first long flexible jumper 11 and the second long flexible jumper 12 is provided with a hot stab 111, 121 at its end for connection with receptacles 221, 321 of the corresponding VCMs 2, 3.

[0071] As shown in more detail in FIG. 1E, the system of the present invention, in one embodiment, further comprises:-a handle for ROV docking on the panel 300;

[0072] a hot stab parking place 301 of the first long flexible connector pipe 11 of the intake line;

[0073] an intake hot stab connector 302;

[0074] a discharge hot stab connector 303;

[0075] a hot stab port 304 of the second long flexible connector pipe 12 of the discharge line; and a crossover valve 305 for interconnecting the intake and discharge lines.

[0076] The general arrangement of the system of the present invention is shown in FIG. 1A and, in a more simplified manner, in FIG. 2A. First, the intake VCM 2 and the discharge VCM 3 are mounted on a first mandrel 41 of a pumping adapter base (PAB) 4 and on a second mandrel 42 of the pumping adapter base (PAB) 4, respectively, preferably by means of a Pipe Laying Support Vessel (PLSV)—not shown. It is worth noting that each of the intake VCM 2 and the discharge VCM 3, according to one embodiment of the present invention, is adapted on the surface, that is, prior to being lowered to the installation site at the first 41 and second 42 mandrels of the PAB 4, to include at least the blind flange 20, 30, the panel support 21, 31 and the jumper interface panel 22, 32 mounted on the panel support 21, 31, in addition to other VCM components, depending on the adaptation to be performed.

[0077] In this sense, FIGS. 3A, 3B, 3C, 3D, 3E and 3F show, in detail, an adapted intake VCM 2, according to one embodiment of the present invention. Likewise, FIGS. 4A, 4B, 4C, 4D, 4E and 4F show, in detail, an adapted discharge VCM 3, according to one embodiment of the present invention. It is worth noting that both the adapted intake VCM 2 and discharge VCM 3 are structurally the same, differing only in their intended functions (one for intake and the other for the discharge of fluids).

[0078] Thus, each VCM 2, 3 comprises a blind flange 20, 30 mounted on a flange of the VCM 2, 3. Further, the panel support 21, 31 is mounted on the blind flange 20, 30 to support the jumper interface panel 22, 32. In one embodiment of the present invention, the support 21, 31 is formed by one or more “D” shaped plates, preferably two, mounted on side portions of the blind flange 20, 30. Furthermore, in alternative embodiments of the present invention, each VCM 2, 3 further comprises an adapter 23, 33, wherein the adapter 23, 33 is a “J” shaped adapter, being mounted on a lower portion of the blind flange 20, 30. Furthermore, each VCM 2, 3 further includes a counterweight assembly 24, 34 suspended on the adapter 23, 33 via a handle 25, 35 to provide greater stability to the VCM 2, 3. The assemblies listed above are preferably made using cases or screws.

[0079] As shown in FIGS. 3A to 3F and 4A to 4F, the interface panel 22, 32 is mounted on the support 21, 31, and has a receptacle 221, 321 for connection of a hot stab, for example. Each VCM 2, 3 further comprises a jumper 222, 322, which connects the receptacle 221, 321 of the interface panel 22, 32 to the blind flange 20, 30. Moreover, in alternative embodiments of the present invention, the interface panel 22, 32 further comprises a pressure gauge 223, 323 for measuring the pressure of a fluid passing through the jumper 222, 322 of the corresponding VCM 2, 3.

[0080] After mounting the intake VCM 2 and the discharge VCM 3 to the corresponding mandrels 41, 42 of the PAB 4, which can be carried out with the aid of a remotely operated vehicle (ROV)—not shown, a DPR riser 14 is lowered towards the PAB 4 containing subsea equipment 5 installed thereon, as shown in FIGS. 1A and 2A. At the end of the DPR riser 14 an installation tool 15 is arranged (such as a pump module installation tool—FIMOBO). It is noted that the DPR riser 14 further comprises the at least one supply umbilical 10, the manifold 1 having the at least one supply umbilical 10 and the first 11 and second 12 long flexible jumpers connected thereto, and the SES 13 having the manifold 1 connected thereto. It is also worth noting that the second long flexible jumper 12 can be connected to the SES 13 directly or indirectly (via a connection on the manifold). Furthermore, the at least one supply umbilical 10 is secured to the DPR riser 14 by means of clamps 16 and can vary in number among one or a plurality of supply umbilicals 10. Preferably, two supply umbilicals 10 are provided.

[0081] Further, in embodiments of the present invention, the DPR riser 14 further comprises a flushing panel 17 mounted above the installation tool 15 to allow control by a ROV of fluid streams towards the PAB 4. The flushing panel 17 therefore receives the two short flexible jumpers 400, 500 from the manifold 1. Furthermore, the long flexible jumpers 11, 12 are also connected to the manifold 1, interconnecting the manifold to the VCM's 3, 4. It is also worth noting that the flushing panel 17 is attached to the DPR riser sub using clamps.

[0082] When the installation tool 15 is on the bottom (either connected or not to the subsea equipment 5), the ROV will connect the hot stab 111 of the first long flexible jumper 11 to the receptacle 221 of the intake VCM 2 and the hot stab 121 of the second long flexible jumper 12 to the receptacle 321 of the discharge VCM 3.

[0083] Next, with the intake and discharge VCMs 2,3 properly connected to the manifold 1 by means of the first and second long flexible jumpers 11, 12, a gaseous fluid (preferably an inert gas, and more preferably N2) will be vented from the at least one supply umbilical 10, passing through the manifold 1 and being directed to the intake VCM 2 via first long flexible jumper 11 and into the subsea equipment 5. The gas fluid acts to break down the hydrate that internally blocks the subsea equipment 5.

[0084] Subsequently, after venting with gas fluid, diesel is circulated from the at least one supply umbilical 10 and the manifold 1, heading towards the intake VCM 2 to the interior of the subsea equipment 5. Then, diesel is returned by the discharge VCM 3 towards the interior of the DPR riser 14 by passing through the second long flexible jumper 12, manifold 1 and SES 13. In addition, it is also possible to circulate water to assist in cleaning the subsea equipment 5 after circulation of diesel. Evidently, circulation of water follows the same circuit as described for diesel.

[0085] It is worth noting that the manifold 1 used by the present invention acts to guide or conduct the fluids within it, so that fluid streams coming from at least one supply umbilical 10 towards the first long flexible jumper 11 are not mixed with the fluid streams coming from the second long flexible jumper 12 towards the SES 13 of the DPR riser 14. Such guidance or conduction is possible due to valves arranged inside the manifold 1, which establish different fluid flow paths.

[0086] It should be noted that FIGS. 2A and 2B show the direction of the intake flow coming from the supply umbilicals 10 towards the flushing panel 17 and in the return direction (discharge) coming from the flushing panel 17 towards the manifold 1 to then have access to the SES 13 towards the DPR riser 14.

[0087] After the blockage removal (venting gas fluid) and cleaning (circulation of diesel or diesel and water) steps, the intake and discharge VCMs 2, 3 are retrieved to the surface by means of the PLSV vessel, without using a rig.

[0088] Therefore, the subsea equipment 5 is fully unblocked and cleaned, becoming ready to be safely demobilized on the surface. It is worth noting that the subsea equipment 5 to be unblocked and cleaned may be a pumping module (MOBO) or any other subsea equipment present in an artificial lift system that may form hydrates inside it.

[0089] When the invention is used for monitoring disconnected abandoned wells, only the features mounted by the PLSV vessel will be required 2, 3, 20, 21, 22, 23, 24, 25, 30, 32, 33, 34, 35, 221, 222, 223, 321, 322 and 323. In some cases, it is possible to modify the panel 32 to allow the installation of a battery bank or other sonic devices for communication with the surface or a visual reading panel by a ROV.

[0090] Thus, based on the system described, the present invention further relates to a method of blockage removal, cleaning and monitoring pressures of subsea equipment which comprises: installing an intake vertical connection (VCM) mandrel 2 onto a first mandrel 41 of a pumping adapter base (PAB), and a discharge VCM 3 onto a second mandrel 42 of the PAB 4;

[0091] deploying a Drill Pipe Riser (DPR) 14 toward a subsea equipment 5 mounted on the PAB 4, the DPR riser 14 further comprising at least one supply umbilical 10, a manifold 1 having the at least one supply umbilical 10 and the first and second long flexible jumpers 11, 12 connected thereto, and the SES 13 having the manifold 1 connected thereto;

[0092] connecting a hot stab 111 of the first long flexible jumper 11 to a receptacle 221 of the intake VCM 2, and a hot stab 121 of the second long flexible jumper 12 to a receptacle 321 of the discharge VCM (3);

[0093] venting a gaseous fluid from the at least one supply umbilical 10 and the manifold 1 toward the intake VCM2 via the first long flexible jumper 11 and into the subsea equipment 5;

[0094] circulating diesel from the at least one supply umbilical 10 and the manifold 1 toward the intake VCM 2 and into the subsea equipment 5; and

[0095] returning the diesel circulated through the interior of the subsea equipment 5 via the discharge VCM 3 and into the DPR riser 14.

[0096] Based on the system and method of the present invention, a fluid circulation circuit is provided to enable the applied fluids to be circulated from one bore to another, either through a pumping adapter base (PAB)—wet Christmas tree (WCT)—well, or directly through the well.

[0097] Those skilled in the art will appreciate the teachings presented herein and will be able to reproduce the invention in the embodiments described as well as in variants thereof, which fall within the scope of the appended claims.

Examples

Embodiment Construction

[0056]Below, reference is made in detail to the preferred embodiments of the present invention illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers shall be used throughout the drawings to make reference to the same or similar features. It should be noted that the drawings are simplified and are not represented to a precise scale, so slight variations are anticipated.

[0057]The present invention relates to systems and methods that use vertical connection mandrels mounted on a pumping adapter base (PAB) to perform blockage removal (hydrate breakdown) and cleaning inside a subsea equipment (such as a MOBO or PAB, for example), by circulating fluid from a borehole to another, wherein each vertical connection mandrel has a line assembly specially adapted to perform ventilation and fluid circulation. After venting a gas, fluids (diesel and water) may be circulated inside the subsea equipment through an HCR umbilical and such fluids may return ...

FIELD OF THE INVENTION

[0001] The present invention is within the technical field of technologies for blockage removal, cleaning and monitoring pressures in subsea equipment used in the oil and gas industry, and, more particularly, it refers to a system and a method that use vertical connection mandrels to perform wells interventions in which the fluid circulation lines are disconnected from a production adapter base (PAB) or a subsea pumping module (MOBO). Furthermore, when used in a PAB whose lines are disconnected, the present invention enables accessories and / or sensors to perform direct shut-in readings in cases where signals are unavailable from sensors from the wet Christmas tree (WCT) (temperature and pressure transducer—TPT and pressure transducer—PT), from the well (permanent downhole gauge—PDG) or even the absence of an annulus sensor.BACKGROUND OF THE INVENTION

[0002] There are instances where wells are temporarily abandoned (wells with lines disconnected from the stationary production unit—SPU). In such cases, disconnection of the lines from the PAB results in loss of the chance to monitor the well pressures, and monitoring is then carried out through vessel visits to read the sensors, provided that such vessels are available. Nevertheless, this is considered a passive approach, as there is no interaction with the well and it is possible to take actions to mitigate risks (well cushioning).

[0003] As long as the shut-in well pressures are within the equipment specified thresholds, monitoring by vessels is deemed valid. However, when pressures approach safe and calculated thresholds, the emergency deployment of a probe is required to be connected to the well and perform a direct intervention in the well.

[0004] Moreover, some wells have an artificial lift system through the installation of pumps on the seabed—submerged centrifugal pumping (SCP). Among the types of pumps available for use in a vertical lift system is the pumping module (MOBO), wherein a pump is placed in a “false well”, the natural-flow well going to the seafloor to produce up to the wet Christmas tree (WCT), and, through a flexible jumper, the product flows to a system composed of a pumping adapter base and a pumping module (PAB-MOBO), from which it is pumped to the production unit (SPU).

[0005] At the MOBO, the well may be abandoned, the lines cleaned and disconnected, without the MOBO capsule being cleaned due to MOBO blockage (hydrate formation). In such instances, it is risky to raise the MOBO assembly without breaking the hydrate formed, basically for two reasons:—depressurization of the MOBO during ascent, which may lead to product leakage into the environment; and—operation with pressurized systems with surface hydrocarbons (demobilization).

[0006] In scenarios involving abandoned and disconnected wells, integrity and pressure monitoring is performed through vessel sporadic visits, during which the vessel uses reading equipment (SASMIC, DATA IWIS) to take spot / historical pressure / temperature readings of production wellbore and annulus. In addition to being a passive monitoring, they depend on the operation / calibration of sensors installed at the WCT (TPT / PT) and at the production / injection string (PDG). If the sensors are lost or absent, the data cannot be read.

[0007] Therefore, there is a need for a system and a method capable of properly and safely remove blockage and clean subsea equipment in intervention operations in wells whose lines are disconnected from a PAB or MOBO. Furthermore, this solution must also provide a structure enabling the installation of additional accessories (e.g., sensors, battery banks), ensuring direct access to the well through both bores.STATE OF THE ART

[0008] The state of the art includes some documents that disclose subject matter that is within the same technological field as the present invention.

[0009] U.S. Pat. No. 9,797,223B1 discloses a method for treating the formation of hydrates in a fluid system including: pumping a fluid at a substantially constant fluid flow rate through a hydrate removal system including a pressure modulator, communicating a vacuum pressure to a piece of subsea equipment from a pressure port of the pressure modulator, closing a valve in the hydrate removal system to cease the fluid flow through the hydrate removal system at the substantially constant fluid flow rate, and communicating a positive pressure greater than the vacuum pressure to the piece of subsea equipment in response to closing the valve of the hydrate removal system.

[0010] The method disclosed by document U.S. Pat. No. 9,797,223B1 is interconnected with a system for hydrate removal at a subsea site. In the solution proposed by the aforementioned document, vacuum is communicated to the piece of subsea equipment from a pressure port of a pressure modulator. During hydrate removal, a surface vessel is connected to and operates a subsea skid that provides vacuum. Furthermore, the subsea skid has a storage tank into which dissolved hydrate flows. In this solution, a hydraulic piston is moved to provide the vacuum. However, document U.S. Pat. No. 9,797,223B1 fails to disclose or suggest a system containing two vertical connection mandrels (VCMs), one for intake and one for discharge, to circulate a gas (N2) through the interior of a pumping module, the VCMs comprising support structures to support a panel with a receptacle; and umbilicals from the Drill Pipe Riser (DPR), which are connected to a manifold to vent the gas to the VCMs, as in the present invention.

[0011] In turn, document WO2022235165A1 discloses a subsea hydrate removal assembly configured for removal of hydrate inside subsea equipment, wherein the subsea hydrate removal assembly comprises a tank at a subsea location. The pressure inside the tank is lower than the pressure at the location of the hydrate inside the subsea equipment. A fluid jumper has a wet-mate connection at a first end and / or at a second end. The fluid jumper constitutes at least part of a fluid flow path that connects the tank and the subsea equipment, thereby enabling fluid communication between the interior of the tank and the hydrate inside the subsea equipment. The subsea hydrate removal assembly is autonomous. A method and a hydrate dissolving tank are also disclosed.

[0012] However, the system disclosed in document WO2022235165A1 proposes that a tank be installed on the seabed close to the hydrate-forming equipment, and that, by means of a jumper, it performs fluid exchange with the subsea equipment to dissolve the hydrate formed.

[0013] Both systems (U.S. Pat. No. 9,797,223B1 and WO2022235165A1) are methods for providing hydrate breakdown but have volumetric limitations and do not contemplate the circulation of different fluids (N2, diesel, inhibited fluid or seawater) after hydrate breakdown to provide cleaning and compliance of the subsea system. In contrast, the present invention discloses a system using two VCMs, each provided with a panel featuring a receptacle (flushing panel), for connecting jumpers from a manifold that is directly connected to the Side Entry Sub (SES) of the DPR column, in order to circulate N2 within a MOBO and thereby promote hydrate break down (blockage removal) and subsequent cleaning of the equipment for future retrieval.BRIEF DESCRIPTION OF THE INVENTION

[0014] The present invention relates to a system and method for blockage removal and cleaning subsea equipment using modified vertical connection mandrels to create a circulation line for venting a gas (N2) to breakdown hydrate that is blocking a pumping module (MOBO) or a production adapter base (PAB). After gas venting, fluids (diesel and water) can be circulated through the interior of the subsea equipment—previously obstructed by the hydrate formation—via an umbilical (preferably a high collapse resistant—HCR—umbilical) and returning through the DPR column for cleaning and preparation of the subsea equipment for future retrieval.

[0015] By implementing the system and method of the present invention, it is possible to break down the hydrate and pump fluid to cushion a well safely and efficiently causing the fluid to circulate and clean the subsea equipment in its demobilization process for future retrieval. Furthermore, the system and method of the present invention can also perform pressure monitoring of subsea equipment.

[0016] Thus, the advantages and objectives of the present invention are achieved by providing a system for blockage removal, cleaning and monitoring pressures of subsea equipment, which comprises:—an intake vertical connection mandrel (VCM);

[0017] a discharge VCM;

[0018] at least one supply umbilical connected to a manifold;

[0019] a first short flexible jumper for interconnecting an intake line from the manifold to a flushing panel;

[0020] a second short flexible jumper for interconnecting a discharge line from the manifold to the flushing panel;

[0021] a first long flexible jumper connected to the flushing panel for the intake line;

[0022] a second long flexible jumper connected to the flushing panel for the discharge line;

[0023] wherein the manifold is connected to a Side Entry Sub (SES) of a Drill Pipe Riser (DPR);

[0024] wherein each VCM from the intake VCM and discharge VCM has a blind flange, a panel support, and a jumper interface panel mounted on the panel support;

[0025] the jumper interface panel of the intake VCM comprising a hot stab receptacle installed thereon, wherein a third jumper connects the receptacle to an inlet of the intake VCM through the blind flange;

[0026] the jumper interface panel of the discharge VCM comprising a hot stab receptacle installed thereon, wherein a fourth jumper connects the receptacle to an inlet of the discharge VCM through the blind flange;

[0027] wherein each of the first and second long flexible jumpers is provided with a hot stab at its end for connection to the respective VCM receptacles.

[0028] Furthermore, the present invention includes a method of blockage removal, cleaning and monitoring the pressures of subsea equipment, which comprises:-installing an intake vertical connection mandrel (VCM) onto a first mandrel of a pumping adapter base (PAB), and a discharge VCM onto a second mandrel of the PAB;

[0029] deploying a Drill Pipe Riser (DPR) toward a subsea equipment installed on the PAB, the DPR further comprising at least one supply umbilical, a manifold having the at least one supply umbilical and the first and second long flexible jumpers connected thereto, and the SES having the manifold connected thereto;

[0030] connecting a hot stab of the first long flexible jumper to a receptacle of the intake VCM, and a hot stab of the second long flexible connector pipe to a receptacle of the discharge VCM;

[0031] venting a gaseous fluid from the at least one supply umbilical and the manifold toward the intake VCM via the first long flexible jumper and into the subsea equipment;

[0032] circulating diesel from the at least one supply umbilical and the manifold toward the intake VCM and into the subsea equipment; and

[0033] returning the diesel circulated through the interior of the subsea equipment via the discharge VCM and into the DPR riser.

[0034] Finally, when used in abandoned / disconnected wells, the proposed system will allow remote pressure and temperature measurement accessories (SASMIC, DATA IWIS) to have direct access to the production bore and the annulus bore in instances where the sensors present in the WCT or in the well are not operational. Although the discharge_VCM panel has a pressure gauge, in these cases, instead of connecting the MOBO cleaning jumper, connecting these data acquisition devices and taking a direct reading of the shut in (production discharge_VCM) or annular pressure (annular discharge_VCM). For this purpose, it would be sufficient for an acquisition vessel to connect the reader via hot stab, open the PAB (AI's) and WCT (Master, Wing) valves.BRIEF DESCRIPTION OF THE FIGURES

[0035] The preferred embodiments of the present invention will be better understood when read in conjunction with the accompanying drawings. It must be understood, however, that the present invention is not limited merely to the precise arrangements and instruments shown.

[0036] Accordingly, the present invention will now be described with reference to its typical embodiments and to the accompanying drawings, in which:

[0037] FIG. 1A shows a schematic view of a system for blockage removal, cleaning and monitoring pressures of subsea equipment, in accordance with an embodiment of the present invention.

[0038] FIG. 1B shows an enlarged schematic view of a manifold of the system for blockage removal, cleaning and pressure monitoring of subsea equipment, which is designated as “manifold”. Such manifold consists of a solid block that will be hung on the SES. Through-holes will be machined in the block to connect the lines of the two HCR umbilicals and an outlet to the SES and providing access to the DPR riser in accordance with one embodiment of the present invention.

[0039] FIG. 1C shows an enlarged schematic view of an intake vertical connection mandrel of the system for blockage removal, cleaning and monitoring pressures of subsea equipment, according to one embodiment of the present invention.

[0040] FIG. 1D shows an enlarged schematic view of an discharge vertical connection mandrel of the system for blockage removal, cleaning and monitoring pressures of subsea equipment, according to one embodiment of the present invention.

[0041] FIG. 1E shows an enlarged schematic view of the flushing panel, from which the intake and discharge jumpers will be connected and laid out. The ends of these jumpers with hot stabs will be placed in the receptacle (parking place) to protect them during maneuvers.

[0042] FIG. 2A shows a simplified schematic view of a system for blockage removal, cleaning and monitoring pressures of subsea equipment, in accordance with an embodiment of the present invention.

[0043] FIG. 2B shows the circulation circuit and the (intake / discharge) lines with the hydraulic diagram, according to one embodiment of the present invention.

[0044] FIG. 3A shows an isometric perspective view of an intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0045] FIG. 3B shows an enlarged view of an adapter and support assembly region on a blind flange of the intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0046] FIG. 3C shows an enlarged view of a connection panel, adapter and support assembly region on a blind flange of the intake vertical connection mandrel, in accordance with one embodiment of the present invention.

[0047] FIG. 3D shows an enlarged view of the intake vertical connection mandrel panel, in accordance with one embodiment of the present invention.

[0048] FIG. 3E shows an enlarged view of a counterweight assembly suspended by the intake vertical connection mandrel adapter, in accordance with one embodiment of the present invention.

[0049] FIG. 3F shows an enlarged view of a third connector pipe connecting a receptacle to a blind flange of the intake vertical connection mandrel, with the connection panel being omitted, in accordance with one embodiment of the present invention.

[0050] FIG. 4A shows an isometric perspective view of a discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0051] FIG. 4B shows an enlarged view of an adapter and support assembly region on a blind flange of the discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0052] FIG. 4C shows an enlarged view of a connection panel, adapter and support assembly region on a blind flange of the discharge vertical connection mandrel, in accordance with one embodiment of the present invention.

[0053] FIG. 4D shows an enlarged view of the discharge vertical connection mandrel panel, in accordance with one embodiment of the present invention.

[0054] FIG. 4E shows an enlarged view of a counterweight assembly suspended by the discharge vertical connection mandrel adapter, in accordance with one embodiment of the present invention.

[0055] FIG. 4F shows an enlarged view of a fourth connector pipe connecting a receptacle to a blind flange of the discharge vertical connection mandrel, with the connection panel being omitted, in accordance with one embodiment of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0056] Below, reference is made in detail to the preferred embodiments of the present invention illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers shall be used throughout the drawings to make reference to the same or similar features. It should be noted that the drawings are simplified and are not represented to a precise scale, so slight variations are anticipated.

[0057] The present invention relates to systems and methods that use vertical connection mandrels mounted on a pumping adapter base (PAB) to perform blockage removal (hydrate breakdown) and cleaning inside a subsea equipment (such as a MOBO or PAB, for example), by circulating fluid from a borehole to another, wherein each vertical connection mandrel has a line assembly specially adapted to perform ventilation and fluid circulation. After venting a gas, fluids (diesel and water) may be circulated inside the subsea equipment through an HCR umbilical and such fluids may return through the Drill Pipe Riser (DPR) for cleaning and preparation for future retrieval of the subsea equipment.

[0058] The description of the present invention will be made below primarily based on the system, only for ease of reference and understanding of the present invention. Nevertheless, the steps of the method associated with the system will be evident to a person skilled in the art, from reading the technical features relative to the system of the present invention. In addition, since the present invention provides direct access to the bores (production / annulus), all the features and changes of VCMs can be used in the embodiment of monitoring disconnected abandoned wells, simply by installing the discharge VCMs directly in the PAB and carrying out valve maneuvers. To this end, pressure measuring devices (SASMIC, DATA IWIS) will be connected to the panel hot stab.

[0059] Thus, reference is made to FIGS. 1A, 1B, 1C, 1D, 1E, 2A and 2B, which show, in general, a system for blockage removal, cleaning and monitoring pressures of subsea equipment, containing its main components, in accordance with one embodiment of the present invention. In one embodiment of the present invention, the system comprises:-an intake vertical connection mandrel (VCM) 2;

[0060] a discharge vertical connection mandrel (VCM) 3;

[0061] at least one supply umbilical 10 connected to a manifold 1;

[0062] a first short flexible jumper (mini jumper HCR) 400 for interconnecting an intake line of the manifold 1 to a flushing panel 17;

[0063] a second short flexible jumper (mini HCR jumper) 500 for interconnecting a discharge line of the manifold 1 to the flushing panel 17;

[0064] a first long flexible jumper 11 connected to the flushing panel 17 for the intake line;

[0065] a second long flexible jumper 12 connected to the flushing panel 17 for the discharge line;

[0066] wherein the manifold 1 is connected to a Side Entry Sub (SES) 13 of a Drill Pipe Riser (DPR) 14;

[0067] wherein each VCM—the intake VCM 2 and the discharge VCM 3—comprises a blind flange 20, 30, a panel support 21, 31, and a jumper interface panel 22, 32 mounted on the panel support 21, 31;

[0068] the jumper interface panel 22 of the intake VCM 2 comprising a hot stab receptacle 221 mounted thereon, a third jumper 222 connecting the receptacle 221 to the inlet of the intake VCM 2 through the blind flange 20;

[0069] the jumper interface panel 32 of the discharge VCM 3 comprising a hot stab receptacle 321 mounted thereon, a fourth jumper 322 connecting the receptacle 321 to the inlet of the discharge VCM 3 through the blind flange 30;

[0070] wherein each of the first long flexible jumper 11 and the second long flexible jumper 12 is provided with a hot stab 111, 121 at its end for connection with receptacles 221, 321 of the corresponding VCMs 2, 3.

[0071] As shown in more detail in FIG. 1E, the system of the present invention, in one embodiment, further comprises:-a handle for ROV docking on the panel 300;

[0072] a hot stab parking place 301 of the first long flexible connector pipe 11 of the intake line;

[0073] an intake hot stab connector 302;

[0074] a discharge hot stab connector 303;

[0075] a hot stab port 304 of the second long flexible connector pipe 12 of the discharge line; and a crossover valve 305 for interconnecting the intake and discharge lines.

[0076] The general arrangement of the system of the present invention is shown in FIG. 1A and, in a more simplified manner, in FIG. 2A. First, the intake VCM 2 and the discharge VCM 3 are mounted on a first mandrel 41 of a pumping adapter base (PAB) 4 and on a second mandrel 42 of the pumping adapter base (PAB) 4, respectively, preferably by means of a Pipe Laying Support Vessel (PLSV)—not shown. It is worth noting that each of the intake VCM 2 and the discharge VCM 3, according to one embodiment of the present invention, is adapted on the surface, that is, prior to being lowered to the installation site at the first 41 and second 42 mandrels of the PAB 4, to include at least the blind flange 20, 30, the panel support 21, 31 and the jumper interface panel 22, 32 mounted on the panel support 21, 31, in addition to other VCM components, depending on the adaptation to be performed.

[0077] In this sense, FIGS. 3A, 3B, 3C, 3D, 3E and 3F show, in detail, an adapted intake VCM 2, according to one embodiment of the present invention. Likewise, FIGS. 4A, 4B, 4C, 4D, 4E and 4F show, in detail, an adapted discharge VCM 3, according to one embodiment of the present invention. It is worth noting that both the adapted intake VCM 2 and discharge VCM 3 are structurally the same, differing only in their intended functions (one for intake and the other for the discharge of fluids).

[0078] Thus, each VCM 2, 3 comprises a blind flange 20, 30 mounted on a flange of the VCM 2, 3. Further, the panel support 21, 31 is mounted on the blind flange 20, 30 to support the jumper interface panel 22, 32. In one embodiment of the present invention, the support 21, 31 is formed by one or more “D” shaped plates, preferably two, mounted on side portions of the blind flange 20, 30. Furthermore, in alternative embodiments of the present invention, each VCM 2, 3 further comprises an adapter 23, 33, wherein the adapter 23, 33 is a “J” shaped adapter, being mounted on a lower portion of the blind flange 20, 30. Furthermore, each VCM 2, 3 further includes a counterweight assembly 24, 34 suspended on the adapter 23, 33 via a handle 25, 35 to provide greater stability to the VCM 2, 3. The assemblies listed above are preferably made using cases or screws.

[0079] As shown in FIGS. 3A to 3F and 4A to 4F, the interface panel 22, 32 is mounted on the support 21, 31, and has a receptacle 221, 321 for connection of a hot stab, for example. Each VCM 2, 3 further comprises a jumper 222, 322, which connects the receptacle 221, 321 of the interface panel 22, 32 to the blind flange 20, 30. Moreover, in alternative embodiments of the present invention, the interface panel 22, 32 further comprises a pressure gauge 223, 323 for measuring the pressure of a fluid passing through the jumper 222, 322 of the corresponding VCM 2, 3.

[0080] After mounting the intake VCM 2 and the discharge VCM 3 to the corresponding mandrels 41, 42 of the PAB 4, which can be carried out with the aid of a remotely operated vehicle (ROV)—not shown, a DPR riser 14 is lowered towards the PAB 4 containing subsea equipment 5 installed thereon, as shown in FIGS. 1A and 2A. At the end of the DPR riser 14 an installation tool 15 is arranged (such as a pump module installation tool—FIMOBO). It is noted that the DPR riser 14 further comprises the at least one supply umbilical 10, the manifold 1 having the at least one supply umbilical 10 and the first 11 and second 12 long flexible jumpers connected thereto, and the SES 13 having the manifold 1 connected thereto. It is also worth noting that the second long flexible jumper 12 can be connected to the SES 13 directly or indirectly (via a connection on the manifold). Furthermore, the at least one supply umbilical 10 is secured to the DPR riser 14 by means of clamps 16 and can vary in number among one or a plurality of supply umbilicals 10. Preferably, two supply umbilicals 10 are provided.

[0081] Further, in embodiments of the present invention, the DPR riser 14 further comprises a flushing panel 17 mounted above the installation tool 15 to allow control by a ROV of fluid streams towards the PAB 4. The flushing panel 17 therefore receives the two short flexible jumpers 400, 500 from the manifold 1. Furthermore, the long flexible jumpers 11, 12 are also connected to the manifold 1, interconnecting the manifold to the VCM's 3, 4. It is also worth noting that the flushing panel 17 is attached to the DPR riser sub using clamps.

[0082] When the installation tool 15 is on the bottom (either connected or not to the subsea equipment 5), the ROV will connect the hot stab 111 of the first long flexible jumper 11 to the receptacle 221 of the intake VCM 2 and the hot stab 121 of the second long flexible jumper 12 to the receptacle 321 of the discharge VCM 3.

[0083] Next, with the intake and discharge VCMs 2,3 properly connected to the manifold 1 by means of the first and second long flexible jumpers 11, 12, a gaseous fluid (preferably an inert gas, and more preferably N2) will be vented from the at least one supply umbilical 10, passing through the manifold 1 and being directed to the intake VCM 2 via first long flexible jumper 11 and into the subsea equipment 5. The gas fluid acts to break down the hydrate that internally blocks the subsea equipment 5.

[0084] Subsequently, after venting with gas fluid, diesel is circulated from the at least one supply umbilical 10 and the manifold 1, heading towards the intake VCM 2 to the interior of the subsea equipment 5. Then, diesel is returned by the discharge VCM 3 towards the interior of the DPR riser 14 by passing through the second long flexible jumper 12, manifold 1 and SES 13. In addition, it is also possible to circulate water to assist in cleaning the subsea equipment 5 after circulation of diesel. Evidently, circulation of water follows the same circuit as described for diesel.

[0085] It is worth noting that the manifold 1 used by the present invention acts to guide or conduct the fluids within it, so that fluid streams coming from at least one supply umbilical 10 towards the first long flexible jumper 11 are not mixed with the fluid streams coming from the second long flexible jumper 12 towards the SES 13 of the DPR riser 14. Such guidance or conduction is possible due to valves arranged inside the manifold 1, which establish different fluid flow paths.

[0086] It should be noted that FIGS. 2A and 2B show the direction of the intake flow coming from the supply umbilicals 10 towards the flushing panel 17 and in the return direction (discharge) coming from the flushing panel 17 towards the manifold 1 to then have access to the SES 13 towards the DPR riser 14.

[0087] After the blockage removal (venting gas fluid) and cleaning (circulation of diesel or diesel and water) steps, the intake and discharge VCMs 2, 3 are retrieved to the surface by means of the PLSV vessel, without using a rig.

[0088] Therefore, the subsea equipment 5 is fully unblocked and cleaned, becoming ready to be safely demobilized on the surface. It is worth noting that the subsea equipment 5 to be unblocked and cleaned may be a pumping module (MOBO) or any other subsea equipment present in an artificial lift system that may form hydrates inside it.

[0089] When the invention is used for monitoring disconnected abandoned wells, only the features mounted by the PLSV vessel will be required 2, 3, 20, 21, 22, 23, 24, 25, 30, 32, 33, 34, 35, 221, 222, 223, 321, 322 and 323. In some cases, it is possible to modify the panel 32 to allow the installation of a battery bank or other sonic devices for communication with the surface or a visual reading panel by a ROV.

[0090] Thus, based on the system described, the present invention further relates to a method of blockage removal, cleaning and monitoring pressures of subsea equipment which comprises: installing an intake vertical connection (VCM) mandrel 2 onto a first mandrel 41 of a pumping adapter base (PAB), and a discharge VCM 3 onto a second mandrel 42 of the PAB 4;

[0091] deploying a Drill Pipe Riser (DPR) 14 toward a subsea equipment 5 mounted on the PAB 4, the DPR riser 14 further comprising at least one supply umbilical 10, a manifold 1 having the at least one supply umbilical 10 and the first and second long flexible jumpers 11, 12 connected thereto, and the SES 13 having the manifold 1 connected thereto;

[0092] connecting a hot stab 111 of the first long flexible jumper 11 to a receptacle 221 of the intake VCM 2, and a hot stab 121 of the second long flexible jumper 12 to a receptacle 321 of the discharge VCM (3);

[0093] venting a gaseous fluid from the at least one supply umbilical 10 and the manifold 1 toward the intake VCM2 via the first long flexible jumper 11 and into the subsea equipment 5;

[0094] circulating diesel from the at least one supply umbilical 10 and the manifold 1 toward the intake VCM 2 and into the subsea equipment 5; and

[0095] returning the diesel circulated through the interior of the subsea equipment 5 via the discharge VCM 3 and into the DPR riser 14.

[0096] Based on the system and method of the present invention, a fluid circulation circuit is provided to enable the applied fluids to be circulated from one bore to another, either through a pumping adapter base (PAB)—wet Christmas tree (WCT)—well, or directly through the well.

[0097] Those skilled in the art will appreciate the teachings presented herein and will be able to reproduce the invention in the embodiments described as well as in variants thereof, which fall within the scope of the appended claims.

Examples

Embodiment Construction

[0056]Below, reference is made in detail to the preferred embodiments of the present invention illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers shall be used throughout the drawings to make reference to the same or similar features. It should be noted that the drawings are simplified and are not represented to a precise scale, so slight variations are anticipated.

[0057]The present invention relates to systems and methods that use vertical connection mandrels mounted on a pumping adapter base (PAB) to perform blockage removal (hydrate breakdown) and cleaning inside a subsea equipment (such as a MOBO or PAB, for example), by circulating fluid from a borehole to another, wherein each vertical connection mandrel has a line assembly specially adapted to perform ventilation and fluid circulation. After venting a gas, fluids (diesel and water) may be circulated inside the subsea equipment through an HCR umbilical and such fluids may return ...

Claims

1. A system for blockage removal, cleaning and monitoring pressures of subsea equipment, comprising:an intake vertical connection mandrel (VCM);a discharge VCM;at least one supply umbilical connected to a manifold;a first short flexible jumper for interconnecting an intake line of the manifold to a flushing panel;a second short flexible jumper to connect a discharge line of the manifold to the flushing panel;a first long flexible jumper connected to the flushing panel for the intake line;a second long flexible jumper connected to the flushing panel for the discharge line;wherein the manifold is connected to a Side Entry Sub (SES) of a drill pipe riser (DPR);wherein each VCM from the intake VCM and the discharge VCM has a blind flange, a panel support and a jumper interface panel mounted on the panel support;the jumper interface panel of the intake VCM comprising a hot stab receptacle mounted thereon, wherein a third jumper connects the receptacle to an inlet of the intake MCV through the blind flange;the jumper interface panel of the discharge VCM comprising a hot stab receptacle mounted thereon, wherein a fourth jumper connects the receptacle to an inlet of the discharge MCV through the blind flange;wherein each of the first long flexible jumper and the second long flexible jumper has a hot stab mounted at its end for connection with the receptacles of the corresponding VCMs.

2. The system, according to claim 1, wherein the intake VCM is mounted on a first mandrel of a pumping adapter base (PAB), and the discharge VCM is mounted on a second mandrel of the PAB.

3. The system according to claim 1, wherein the panel support is formed by one or more “D” shaped plates mounted on side portions of the blind flange4. The system, according to claim 1, wherein each VCM further comprises an adapter, wherein the adapter is a “J” shaped adapter, being mounted on a lower portion of the blind flange.

5. The system, according to claim 1, wherein each VCM further includes a counterweight assembly suspended on the adapter by means of a handle.

6. The system, according to claim 1, wherein the interface panel further comprises a pressure gauge7. The system, according to claim 1, wherein the at least one supply umbilical is secured to the DPR riser by means of clamps.

8. The system, according to any claim 1, further comprising two supply umbilicals.

9. The system, according to claim 1, further comprising:a handle for docking a ROV to the panel ;a hot stab port for the first long flexible jumper of the intake line;an intake hot stab connector;a discharge hot stab connector;a hot stab port for the second long flexible jumper of the discharge line; anda crossover valve for interconnecting the intake and discharge lines.

10. The system, according to claim 1, wherein the flushing panel is attached to the DPR sub riser using clamps.

11. A method of blockage removal, cleaning and monitoring pressures of subsea equipment, which uses the system as defined in claim 1, the method comprisingmounting an intake vertical connection mandrel (VCM) on a first mandrel of a pumping adapter base (PAB) and a discharge VCM on a second mandrel of the PAB;descending a drill pipe riser (DPR) towards a subsea equipment mounted on the PAB, wherein the DPR riser further comprises the at least one supply umbilical, a manifold having the at least one supply umbilical and the first and second long flexible jumpers connected thereto, and the SES having the manifold connected thereto;connecting a hot stab of the first long flexible jumper to a receptacle of the intake VCM and a hot stab of the second long flexible jumper to a receptacle of the discharge VCM;venting a gaseous fluid from the at least one supply umbilical and the manifold toward the intake VCM via the first long flexible jumper and into the subsea equipment;circulating diesel from at least one supply umbilical and the manifold, toward the intake VCM and into the subsea equipment; andreturning the diesel circulated inside the subsea equipment through the discharge VCM toward the interior of the DPR riser.

12. The method according to claim 11, wherein the gaseous fluid is preferably an inert gas, and more preferably N2.

13. The method according to claim 11, further comprising circulating water after the diesel returns through the interior of the DPR riser.

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