RU2017933C1 - Subsea wellhead equipment for operation of well cluster - Google Patents

Abstract

FIELD: well drilling. SUBSTANCE: equipment is provided with common central control and maintenance block connected by means of tubular passage for servicing personnel and service lines with radially disposed periphery self-contained blocks each of which has retractable water-separating adapter installed on wellhead for lifting and sealing of operation equipment upon completion of drilling operations. Central block has rooms of dwelling complex and hatch with coaming platform for landing of the underwater apparatus. EFFECT: higher efficiency. 4 dwg

Description

 The invention relates to underwater means for the extraction of oil or gas at various depths of the shelf zone, as well as in waters with difficult ice conditions.

 The well-known closed-type operating system of the company "Cameron", Germany, which allows for the development and maintenance of wells at sea depths. One of the main elements of this system is a working chamber installed on the wellhead drilled in the seabed, which is equipped with wellhead fountain fittings in advance. The camera is mounted on the underwater wellhead with a standard hydraulic connection. The chamber has atmospheric pressure, so operators can work without diving equipment. Operators are delivered to the place of work by underwater vehicles having a docking system with a working chamber. The chambers are formed into modular structures (modular system) that allow serving several wells. For operation of the well cluster, Cameron modular systems are used, assembled from standard elements (working chambers). Before installing the cameras on the seabed, a conductor is installed, the configuration and location of which ensures the drilling and operation of the required number of wells. The working chamber is mounted on the underwater mouth of each equipped well with a standard hydraulic connector. After that, a crew of specialists descends into the chamber to put it into operation.

 To ensure the operation of the Cameron operational modular system, wells should be drilled and wellhead installed prior to installation of working chambers, which is associated with a large simultaneous concentration of technical means (drilling platform, transport vessels, vessels and equipment designed for underwater operations) . This complicates work in harsh marine conditions, increases their cost, reduces reliability. Access to the working chamber for inspection, adjustment and repair of wellhead fountain fittings is carried out only by underwater means (apparatuses, bells, divers) into each chamber separately.

 The aim of the invention is to reduce the cost of creating and operating an underwater module and increasing its reliability with the universal possibilities of its operation.

 The goal is achieved by the fact that the underwater module for operating the wellbore is made with a single central unit for placing control and maintenance personnel and is connected by transitions with independent, separately standing working chambers radially and peripherally located with respect to the central unit, each of which together with wellhead fountain fittings has a retractable water separating tubular element (adapter) with a plug installed on the wellhead with the possibility of lifting and sealing at the end of the drilling from to be installed on the same wellhead wellhead wellhead equipment.

 The significant difference between the proposed solution lies in the fact that the entire design of the underwater module for operating the well cluster is assembled onshore, after which it is transported to the production site in an assembled (working) state and installed on the seabed without preliminary preparation of wells.

 The radial arrangement of the peripheral (drilling) working chambers with respect to the central block ensures the compactness of the entire structure, and also greatly facilitates the work associated with the installation of the drilling platform when drilling a well, since each well already has its own coordinate. The module provides simultaneous drilling and production operations through peripherally located working chambers, which allows for well drilling, installation, commissioning, inspection and repair of wellhead fountain fittings, production of a product of production in each working chamber, respectively, independently of the other, without violating the overall technological cycle of the entire module , which confirms the universality of the solution. Unified management and the ability to locate service personnel in the central unit, the ability to communicate on transitions with each working chamber at atmospheric pressure without the use of underwater technical means, provide increased reliability and reduced operating costs of the module.

 Service personnel can be delivered for work on the module by an underwater vehicle from a drilling platform or a transport vessel, or by a tunnel from the shore (at a distance of no more than 10 km) to its central unit (the delivery method depends on the production area), which expands universality solutions.

 In FIG. 1 shows a module view from above; figure 2 is a section aa in figure 1; in FIG. 3 - shows the peripheral working chamber when drilling a well; figure 4 - it is during the operation of the wellhead fountain.

 A stand-alone underwater production and drilling module (Figs. 1 and 2) consists of a central unit 1 and separate independent peripheral working chambers 2, interconnected by tubular passages 3 for the passage of the personnel of the module, as well as for laying production pipelines, cable and other communications. In the central block 1 there is a residential complex, a central control post, life support systems (not shown in the figures). The central unit 1 is divided by decks into several tiers, and on top it is equipped with a hatch with a coaming platform 4 for landing an underwater vehicle with the personnel of the module. Each peripheral working chamber 2 is insulated, sealed and located radially relative to the central unit. Through the working chamber, a well is drilled from an offshore drilling platform. (The offshore drilling platform during its joint operation with the underwater module has the ability to move around its perimeter outside its dimensions, which makes it possible to drill through each working chamber 2).

 The tightness of the housing of each working chamber 2 is provided by a retractable water separating tubular element (adapter) 5. The sliding water separating adapter 5 is a pipe, at the ends of which a trapezoidal thread is made for connection from the top to the column 6 of water separating pipes, and from the bottom inside the working chamber to the wellhead with a bottom suspension 7 . The adapter 5 at the entrance to the housing of the sealed working chamber 2 is sealed with a stuffing box located in the support pedestal with guide bushings 8, which accepts lateral loads and transmitted adapter 5 from the riser while drilling (power flow, agitation, etc.). In the working chamber 2 there is a lifting device 9 that provides the lifting, moving and installation of the wellhead fountain 10, which, when drilling a well, is mounted on a separate rack inside each working chamber 2.

 The module works in the following modes.

 Drilling, which is conducted from an offshore drilling platform by a drilling rig connected by a column 6 of water separating pipes to an adapter 5, which is fixed to the wellhead inside the working chamber 2.

 Preparation for operation of the well is carried out at the end of the drilling process (figure 4); the adapter 5 is disconnected from the wellhead and lifted together with the column 6 of riser pipes, using an offshore drilling platform, a sealed plug 11 is installed to ensure the tightness of the housing of the working chamber 2, with the subsequent disconnection of the column 6 of riser pipes from the adapter 5. After that, the lifting device 9 installs wellhead fountain fittings 10 at the wellhead and a pipeline to it from the general production pipeline of the module (not shown in the figures).

 The well is operated through wellhead fountain fittings 10, which are controlled from the central block 1. The production product from each well enters the module’s general production pipeline with subsequent supply to the shore via the main underwater pipeline (depending on the production product - oil, gas - there may be various options for the technology of its collection and transportation).

 The use of the invention will expand the possibility of oil and gas production in the development of new offshore fields, including on the shelf of the freezing seas, with lower costs and greater mobility of their operation, regardless of meteorological factors and the state of the sea, and significantly increase the reserves of this raw material for the national economy, which show studies on the development of the shelf of the seas of the Far Eastern region.

Claims (1)

 UNDERWATER HEALTH EQUIPMENT FOR OPERATION OF A WELL HUB, containing hermetic working chambers installed on the mouth of each of the underwater wells equipped with a string of pipes, characterized in that, in order to increase the reliability of the equipment while expanding its functions and simplifying maintenance, it is equipped with a central unit control having transitions for communication with sealed cameras located radially and peripherally relative to the Central unit, each of the cameras is made with a retractable a water-separating tubular element with a plug connected to the pipe string, the latter being installed with the possibility of sealing the chamber when it is extended.

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