RU2779235C1 - Offshore production complex for the production, preparation and processing of raw gas for the production of liquefied natural gas, a wide fraction of light hydrocarbons and stable gas condensate based on gravity type (gtb) - Google Patents

Abstract

FIELD: offshore production facilities.

SUBSTANCE: invention relates to offshore production facilities and can be used to create offshore production facilities for the production, preparation and processing of hydrocarbons. The offshore industrial complex for the production, preparation and processing of raw gas contains a base and a topside located on it, including a drilling complex, a flare plant, technological equipment for the preparation and processing of raw gas and a residential building. At the base there are storage tanks for raw gas processing products. The base is a gravity-type base (GTB) having a central and protruding parts. The central part has the shape of a rectangular parallelepiped with a top plate. The protruding part of the GTB is located on the sides of the central part along its entire perimeter and has vertical outer walls. The protruding and central parts of the GTB have a common bottom plate. The height of the protruding part is less than the height of the central part. The central part of the GTB has internal longitudinal and transverse walls forming ballast compartments and compartments in which tanks are located for storing raw gas processing products. The protruding part of the GTB has internal walls perpendicular to its external walls and forming ballast compartments. The central part of the GTB has an intermediate horizontal slab, on which tanks are located for storing one of the raw gas processing products. Integrated with the GTB and topsides design are berths for offloading feed gas processing products along both longer sides of the GTB.

EFFECT: ensuring the possibility of using the marine complex in the Arctic, in water areas with an ice regime.

6 cl, 7 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to offshore production facilities and can be used in the creation of offshore production facilities for the production, preparation and processing of hydrocarbon raw materials in order to produce liquefied natural gas (LNG), a wide fraction of light hydrocarbons (NGL) and stable gas condensate (SGK) at CDP and which are a new type of offshore oil and gas facilities - GDСPSO (gravity drilling chemical production storage and offloading).

BACKGROUND OF THE INVENTION

One of the most common technical solutions for industrial complexes for the processing of hydrocarbon raw materials at sea are FPSO systems (floating production storage and offloading).

In particular, FLNG (floating liquefied natural gas) systems are used for offshore LNG plants. In this case, the LNG plant is part of a floating installation for the production, treatment and liquefaction of natural gas, storage and offloading of LNG. FLNG is applied to the development of offshore natural gas fields and is installed directly on the field by means of an anchor and/or mooring system.

This design has the following drawback.

FLNGs are not used in water areas with heavy ice conditions due to the inability to provide reliable positioning necessary to connect the hull of the installation to the subsea production system in conditions of ice shifts, and thus their use is limited to the development of offshore fields in non-freezing seas.

Known integrated production complex for the processing of raw gas on the basis of gravity type (GST) (RU 2762588 C1, published 12/21/2021), intended for operation in the coastal zone and containing GBS, on which topside modules are located, in which process equipment is located. The GBS design is adapted for use in water areas with severe ice conditions.

This complex has the following disadvantages.

1. The complex requires connection to the onshore infrastructure for the production and preparation of hydrocarbons.

2. The complex allows the shipment of hydrocarbons only from one side of the GBS facing the sea area.

3. The GBS has a large number of compartments of a significant total volume, which are used exclusively as ballast compartments. These compartments do not have other functionality.

The closest to the proposed offshore complex is the technical solution (KR20170049075 (A), published on 05/10/2017), according to which the floating installation for the production, treatment and liquefaction of natural gas, storage and offloading of LNG includes a drilling complex and is an FDLPSOU installation (floating drilling LNG production storage offloading unit). The installation includes a floating base (vessel), a drilling rig for the production of petroleum gas, a flare plant, process equipment, including gas treatment plants (cleaning and drying), gas fractionation and gas liquefaction plants, an unloading device, a power plant, living quarters and premises for control and management, and tanks for liquefied natural gas (LNG), liquefied petroleum gas (LPG) and stable gas condensate (SGK) and a mooring turret located in the ship's hull.

FDLPSOU is applied to the development of offshore natural gas fields and is installed directly on the field using a dynamic positioning system and connected to a subsea production system using a turret.

This design has the following disadvantages.

1. It is difficult for an FDLPSOU rig to simultaneously drill production wells and produce hydrocarbons to provide the positioning required for drilling with a production turret connected.

2. FDLPSOU, like FLNG, is not used in water areas with severe ice conditions due to the inability to provide reliable positioning.

DISCLOSURE OF THE INVENTION

The technical problem solved by the invention is as follows. Taking into account the increase in the share of hydrocarbons produced at offshore fields in the Arctic, there is an urgent need to develop a new efficient production complex for the production and processing of hydrocarbon raw materials, adapted for use in the Arctic, in water areas with ice conditions.

To solve this problem, a marine industrial complex for the extraction, preparation and processing of raw gas (hereinafter GDCPSO - gravity drilling chemical production storage and offloading) is proposed, containing a base and a topside located on it, which includes a drilling complex, a flare unit, technological equipment for preparing and processing of raw gas and a residential building, and at the base there are tanks for storing products of processing of raw gas, while, according to the invention, the base is a gravity-type base (CGT), which has a central part and a protruding part, the central part has the shape of a rectangular parallelepiped with the top plate, on which the specified technological equipment is located, and the protruding part of the GBS is located on the sides of the central part along its entire perimeter and has vertical outer walls, the protruding and central parts of the GBS have a common bottom plate, and the height is of the stepped part is less than the height of the central part, while the central part of the GBS has internal longitudinal and transverse walls forming compartments, which include ballast compartments and compartments in which tanks for storing raw gas processing products are located, and the protruding part of the GBS has internal walls perpendicular to it external walls and forming ballast compartments.

In the preferred embodiment, the drilling complex includes a drilling rig located at the end section of the central part of the CDP, the compartments of which under the drilling rig are boreholes.

Also in the preferred embodiment, the compartments of the central part of the GBS, formed on one side by its end walls, include at least one compartment for consumables, at least one compartment for chemicals and at least one compartment for waste.

In addition, part of the compartments of the CDP central part, including at least one of the compartments formed on one side by its end walls, may be auxiliary compartments.

In addition, the central part of the GBS also has an intermediate horizontal slab, on which tanks are located for storing one of the raw gas processing products, namely, liquefied natural gas, and between the intermediate horizontal slab and the lower slab, longitudinal and transverse walls are located, forming additional ballast compartments .

In addition, some of the compartments in the central part of the GBS form reservoirs for storing other feed gas processing products, namely, stable gas condensate and a wide fraction of light hydrocarbons.

GDCPSO is used for the extraction, preparation and processing of hydrocarbon feedstock for the purpose of producing LNG, NGL and SGK.

GDCPSO is used for offshore field development and is installed offshore, directly on the field without the use of an anchor, mooring system or other system. GDCPSO is immovably fixed after immersion on the base 9 by filling the ballast system.

GDCPSO drills production wells and prepares reservoir products for further processing.

The technical result achieved by the proposed technical solution is as follows.

The presence of the protruding part of the CDP increases the buoyancy of the GDCPSO and reduces its draft during transportation to the installation site.

The increased width of the lower part of the GBS increases the stability of the entire structure at the stage of its transportation, which makes it possible to install a topside structure of greater height and weight on the GBS. During the transportation phase, sea water is used as ballast.

The presence of ballast compartments on the periphery of the CDP in its protruding part simplifies the balancing of the CDP, that is, setting the CDP on an even keel, without heel and trim. At the same time, part of the compartments that perform the functions of ballast during transportation, during operation, after the installation of the CDP at the field, is used as compartments for storing consumables, chemicals, waste, auxiliary and engineering compartments and wells.

Sea water and solid ballast can be used to fill the ballast compartments to hold the GDCPSO in place.

The protruding part of the GBS protects the central part from the impact of ice and emergency bulk of the ship.

In addition, the protruding part serves as the basis for berths for the shipment of raw gas processing products - LNG, NGL and SGK.

LIST OF DRAWINGS

In FIG. 1 shows a diagram of the proposed offshore complex, top view.

In FIG. 2 is a cross section along A-A in FIG. one.

In FIG. 3 is a longitudinal section along B-B in Fig. one.

In FIG. 4 is a longitudinal section along B-B in FIG. one.

In FIG. 5 - layout of the main compartments of the CDP.

In FIG. 6 is a diagram of the location of the vertical walls of the CDP in the section G-G in FIG. 2.

In FIG. 7 is a diagram of the location of the vertical walls of the CDP in the section D-D in FIG. 2.

EXAMPLES OF CARRYING OUT THE INVENTION

The proposed marine complex GDCPSO is a technical device of full factory readiness, which is a set of technological, engineering and auxiliary equipment for drilling, production of raw gas, treatment, production, storage and shipment of LNG, NGL and SGK.

The GDCPSO is manufactured at a specialized facility and delivered to the location by floating towage.

GDCPSO is installed on a specially prepared base 9 on the seabed (Fig. 2-4) directly at the field, which is the source of raw materials, or at a distance from the field technologically accessible for hydrocarbon production, according to the scheme of its development, at depths over 14 meters. In order to avoid erosion of the base 9 under the GBS and the bottom of the water area around the GBS, the bottom can be fixed in the form of gabions or other products of a similar purpose, or a berm can be filled. Upon completion of the development of the field, the production complex can be deballasted and moved to another area of operation. This allows it to be used for hydrocarbon production in small and medium-sized hydrocarbon deposits.

The creation of the GDCPSO will allow the development of fields located at shallow depths in the waters of the Arctic seas.

At GDCPSO, the main elements of production, preparation and processing of hydrocarbon feedstock - feed gas are CDP and the topside - drilling and process equipment in a modular design (Fig. 1 - 4).

CDP is a three-dimensional reinforced concrete structure that serves as a support block for a drilling complex, including a drilling rig 10, a flare rig 11, technological modules 12 of the upper structure and a residential module 13, as well as the function of storage for raw gas processing products - LNG, NGL and SGK, consumables, chemicals, waste, and designed to be installed on the seabed under its own weight.

The central part 1 of the CDP has the shape of a rectangular parallelepiped and has a top plate 3. On the sides of the central part 1 along the entire perimeter there is a protruding part 2 of the CDP. The central 1 and protruding 2 parts of the CDP have a common bottom plate 4, and the height of the protruding part 2 is less than the height of the central part 1 of the CDP.

The central part 1 of the CDP includes the main supporting structures, in the form of vertical walls 6 and horizontal slabs (upper 3, lower 4 and intermediate 5). The bearing structures provide the required spatial rigidity of the GDCP frame, including during the GDCPSO transportation and while it is afloat until installation. Vertical walls 6, made of reinforced concrete, also provide for the division of CDP into compartments in accordance with their functional purpose.

On the upper slab 3 CDP there are reinforced concrete supports 7, on which a drilling rig 10, a flare rig 11, technological modules 12 and a residential building - a residential module 13 are installed.

The vertical walls 6 also play the role of load-bearing structures that transfer the load from the topside to the bottom slab 4 and the base 9, so reinforced concrete supports 7 are located above the intersections of the vertical walls 6 of the central part 1 of the CDP.

The upper plate 3 CDP has slopes from the central longitudinal line to the edges to remove precipitation and technological spills. The design of the top plate 3 is designed for explosion loads in case of emergencies. In order to protect the upper plate 3 from the spillage of cryogenic media, steel with enhanced cold resistance characteristics is used as reinforcement.

To distribute the loads from the storage tanks of one of the products of raw gas processing - LNG, a horizontal intermediate plate 5 is provided, located between the upper 3 and lower 4 plates. The vertical walls 6 located under this plate provide the transfer of loads to the lower plate 4 and the spatial rigidity of the structure.

The main material of the central part of GBS 1 is reinforced concrete, based on modified concrete of normal density with prestressed reinforcement.

The central part 1 of the CDP is divided by vertical walls 6 into compartments (Fig. 5-7). Part of the compartments - compartments 14, 15, 16 are used to store finished products; part of the compartments - compartments 17, located along the longer sides of the CDP - to accommodate water or solid ballast. Compartments 18 formed on one side by the end walls of the central part 1 are used as boreholes, at least one compartment 19 is used to store consumables, at least one compartment 20 is used to store chemicals, and at least one compartment 21 is used to store waste, as well as at least one compartment 22 as an auxiliary. Inside the central part 1 of the CDP there are also engineering compartments 23. These compartments 19-23 during transportation and during operation also perform the functions of ballast. At the same time, consumables, chemicals and waste in the respective compartments 19, 20 and 21 during the operation period are also considered as ballast.

The compartments 17 formed by the vertical walls 6 of the protruding part 2 of the CDP are included in the ballast system.

The GDCPSO has the ability to float while being transported through the water to the installation site and can withstand the impact of ice in the waters with ice regime. The transition of the GDCPSO from a floating state to a stationary state at the installation site on the base 9 is ensured by filling the ballast compartments 17 with sea water.

The external dimensions of the GDCPSO may vary depending on the performance.

The main space-planning solutions for GBS structures are determined by technological parameters, as well as internal and external loads acting on the GBS structure, taking into account their most negative possible combination.

The protruding part 2 of the CDP performs the following main functions:

- achievement of the required target parameters of CDP buoyancy;

- placement of ballast compartments 17, intended mainly for balancing the CDP, which ensures that the CDP is afloat on an even keel, without roll and trim;

- formation of a natural protective barrier in the event of a design emergency collision / ship bulk; protruding part 2 will be able to receive and absorb the main impact energy, eliminating damage to the main volume of the CDP frame, which ensures the safety and integrity of the main tanks and supporting structures of the topside;

- placement of auxiliary technological and offshore equipment that ensures the mooring of tankers and the shipment of LNG, NGL and SGK.

Tanks for storage of LNG, NGL and SGK are placed in compartments 14, 15, 16 GBS.

In the central part 1 of the GBS there are several tanks (Fig. 5), the design of which depends on the properties of the stored substance.

Membrane-type tanks are used for LNG storage. In this case, a reservoir is installed inside the concrete compartment, consisting of a metal membrane made of stainless steel or invar (iron-nickel alloy), separated from the concrete structures by a layer of thermal insulation. The thermal insulation layer is located directly on the top 3 and intermediate 5 plates and vertical walls 6 of the CDP, transferring the load from the tank and the liquid contained in it to the specified enclosing structures. Thus, the slabs and walls of the GBS are the supporting structures of the membrane tanks, forming a single structure with them. To prevent leakage, the bottom and side surfaces of the membrane tanks contain a secondary barrier in the form of an additional membrane installed inside the thermal insulation layer.

Tanks for NGL and SGK storage are formed by concrete compartments 15 and 16 of CDP, the enclosing structures of which play the role of a protective barrier.

Smaller compartments 19, 20 and 21 for storing consumables, chemicals and waste as reservoirs (e.g. diesel, oil, drilling fluid, process water, glycol solution, drilling cuttings, drilling waste water, demineralized water, fresh water etc.) are placed along the end sides of the CDP.

Auxiliary 22 and engineering 23 compartments in the central part 1 of the CDP are located on the sides of the main compartments 14, 15 and 16 for storing LNG, NGL and SGK and in the center between them. These compartments are intended for technological needs, placement of equipment, tanks of technical liquids, as well as access and evacuation routes for personnel. The presence of dry compartments along the perimeter of the main hydrocarbon storage compartments makes it possible to inspect the outer surfaces of the enclosing walls of compartments 14, 15 and 16 - storage tanks for LNG, NGL and SGK.

Engineering equipment includes: power supply system, including substations; heating, ventilation, air conditioning (HVAC) systems; ballast water heating and recirculation system; water supply and sanitation systems; pumps and pipelines of the fire extinguishing system; foam fire extinguishing system blocks; system of electrochemical protection against corrosion; communication and warning systems and a video surveillance system. Most of the engineering equipment is placed on the top plate 3 and/or in/on the technological modules 12, the rest is in the engineering compartments 23. The auxiliary compartments 22 can remain empty, they contain ladders and manholes for access inside.

Reinforced concrete supports 7 of the modules of the upper structure on the upper slab 3 of the CDP provide the perception of support reactions to the main load-bearing structures of the CDP from the drilling rig 10, the flare rig 11, the technological modules 12 and the residential module 13. Structurally, the supports 7 are made in the form of reinforced concrete pylons with caps for placing embedded details.

The location of the reinforced concrete supports 7 is determined based on the presence of the intersection of the vertical walls 6 of the GBS, which ensures the distribution of loads from the topside modules.

The height of the reinforced concrete supports 7 is chosen in such a way as to provide sufficient space between the top plate 3 of the GBS and the lower part of the drilling rig 10, the flare unit 11, the technological modules 12 and the accommodation module 13 to accommodate pipeline and cable communications 24 between the topside and the equipment in the compartments of the GBS and for moving people and equipment along the upper plate 3 CDP.

The CDP ballast system includes internal ballast compartments 17, including under the intermediate plate 5, formed by vertical walls 6, as well as external ballast compartments 17, located respectively in the central part 1 of the CDP and in the protruding part 2 of the CDP. To prevent freezing of water in ballast compartments 17, a recirculation and ballast heating system is provided. To heat the water in the ballast compartments 17, the recovered heat from the exhaust gases of gas turbines installed on topside modules is used.

The ballast system performs two main functions:

- ballasting, i.e. changing the mass of the CDP, ensuring the necessary settlement of the CDP while afloat and the stability of the structure after installing the CDP on base 9;

- CDP balancing, i.e. setting the CDP on an even keel, without heel and trim while afloat by compensating with the help of water ballast for the deviation of the center of gravity of the structure from its geometric center.

The upper structure includes technological equipment, arranged from technological modules 12. The number of technological modules 12 is determined at the design stage of the production complex. The location of the modules on the GBS is based on their mass in order to ensure that the center of gravity of the GDCPSO is located near the geometric center of the GBS in order to reduce the amount of ballast water required to balance the structure while afloat.

Technological modules 12 are a three-dimensional steel frame-and-frame structure, saturated with technological equipment and equipment of the electrical system, automation systems, etc.

Fundamentally, in execution and layout, the technological modules 12 do not differ from the modules of the topside, implemented in the oil and gas industry at offshore oil and gas facilities of other types.

The modules house technological installations for cleaning and preparation of raw gas, equipment for gas liquefaction, equipment for loading LNG, NGL and SGK to tankers, as well as auxiliary equipment and utilities.

Technological systems for the preparation and disposal of well products are designed to work with reservoir fluid and produce gas, NGL and stable gas condensate. These systems are analogous to systems commonly used in onshore fields. The difference lies in the use of marine equipment.

For ease of maintenance of equipment and movement of personnel, each technological module 12 includes several tiers (decks). The main tier 8 of all technological modules 12 is located at the same height, making it possible to combine escape routes and cargo movement routes through the entire topside structure, which reduces the load on the CDP top plate 3. The remaining tiers of technological modules 12 vary in height depending on the equipment and functionality of the module.

Berths for offloading 25 LNG, NGLs and GLK to tankers are integrated with the GBS and topsides structure and are located along both longer sides of the GBS. Berths 25 are equipped with mooring devices, fenders and technological platforms with standers and other marine and technological equipment that ensures shipment.

The compartments, with the exception of the main LNG storage compartments 14, may be separated by transverse walls. In the walls inside the ballast compartments 17, holes for the overflow of ballast water can be provided, and in the bulkheads of the auxiliary and engineering compartments 22 and 23 - passages for personnel, slots and niches for laying communications.

The drilling complex is designed for operating conditions at offshore fields and has an appropriate climatic design. To ensure the work associated with the well drilling processes, the drilling complex includes a drilling rig 10 (Fig. 1, 4) with a displacement device, blowout prevention equipment, drilling pumps, a drilling mud circulation system, a cementing complex, a pneumatic transport system, a preparation and injection system into the slurry slurry formation, drilling wastewater collection system, hydraulic drive for moving the mechanisms of the drilling rig 10, bulk materials storage, etc.

The 10 GDCPSO drilling rig provides year-round cluster drilling and workover operations for vertical, deviated and horizontal wells. Pad drilling is provided by moving the drilling rig 10 along the entire grid of wells.

The drilling rig 10 is located on the end section of the CDP central part 1, the compartments 18 of which under the drilling rig are wells.

The drilling rig 10 includes a support frame with a substructure equipped with equipment and systems for driving a well. Devices for moving the drilling rig 10 allow you to install it over any intended point of the grid of wells and fix the drilling rig 10 at this point. Drilling is carried out through boreholes 18 in CDP (Fig. 4-7).

Technological systems for the preparation and disposal of well products are designed to work as part of a single GDCPSO.

High and low pressure flare systems are provided for the safe disposal of gases, including hydrocarbon gases/vapours, not used to generate electrical and thermal energy, from high and low pressure process equipment, respectively. The flare system is also used in emergency and/or blowdown situations. Gas from high and low pressure systems is fed to the flare unit 11 to the flare tip, where it is burned (Fig. 1, 3).

As a block of residential premises, the use of a residential module 13 is envisaged (Fig. 1, 3, 4). Residential module 13 is a safe, fully functional, fire-resistant, secure building that meets all necessary architectural, structural, sanitary and hygienic and general technical requirements. Residential module 13 is formed as part of the topside in conjunction with other structures and systems.

Residential module 13 is a modular structure containing a complex of residential, public, sanitary, medical and food facilities, as well as auxiliary equipment rooms designed to ensure the functioning of residential module 13.

Residential module 13, meeting the safety requirements, is located at the maximum possible distance from the most dangerous technological zone in which the drilling complex 10 is located.

Claims (6)

1. An offshore industrial complex for the production, treatment and processing of raw gas, containing a base and located on the upper structure, which includes a drilling complex, a flare plant, process equipment for the preparation and processing of raw gas and a residential building, and storage tanks are located at the base raw gas processing products, characterized in that the base is a gravity-type base (GBS), which has a central part and a protruding part, the central part has the shape of a rectangular parallelepiped with an upper plate on which the specified technological equipment is located, and the protruding part of the GBS is located with sides of the central part along its entire perimeter and has vertical outer walls, the protruding and central parts of the GBS have a common bottom plate, and the height of the protruding part is less than the height of the central part, while the central part of the GBS has internal longitudinal and transverse walls, forming compartments, which include ballast compartments and compartments in which tanks for storing raw gas processing products are located, and the protruding part of the GBS has internal walls perpendicular to its outer walls and forming ballast compartments, while the central part of the GBS also has an intermediate horizontal plate, on where tanks for storage of one of the feed gas processing products are located, between the intermediate horizontal plate and the lower plate there are longitudinal and transverse walls forming additional ballast compartments, and with the design of the GBS and the topside, berths for loading feed gas processing products are integrated, located along both more long sides of the CDP. 2. The complex according to claim. 1, characterized in that the drilling complex includes a drilling rig located on the end section of the central part of the CDP, the compartments of which under the drilling rig are boreholes. 3. The complex according to claim 1, characterized in that the compartments of the central part of the CDP, formed on one side by its end walls, include at least one compartment for consumables, at least one compartment for chemicals and at least one compartment for waste. 4. The complex according to claim 1, characterized in that part of the compartments of the central part of the CDP, including at least one of the compartments formed on one side by its end walls, are auxiliary compartments. 5. The complex according to claim 1, characterized in that tanks for storing liquefied natural gas are located on the intermediate horizontal plate. 6. The complex according to claim 1, characterized in that part of the compartments of the central part of the GBS form reservoirs for storing stable gas condensate and a wide fraction of light hydrocarbons.

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