RU2040637C1 - Submersible drilling rig - Google Patents

Abstract

FIELD: ship building. SUBSTANCE: submersible drilling rig includes body accommodating drilling equipment, material reserves and attending personnel. Body lower part has hatch which is connected with sea bottom by pipe filled with heavy fluid whose density exceeds that of sea water to unload walls from external hydrostatic pressure by equalizing pressure in pipe and environment. Density of fluid filling the pipe is determined from relation given in invention description. EFFECT: higher efficiency in development of offshore fields of hydrocarbons due to simplified design, higher adaptability to manufacture of drilling equipment, and provision of use of existing converted ship building enterprises without considerable modernization for manufacture of offered drilling rigs. 1 dwg

Description

 The invention relates to shipbuilding, and more particularly to the design of technical means for the development of the ocean.

 To ensure the effective operation of offshore drilling rigs in severe hydrometeorological conditions, including in areas covered with ice, it is considered advisable to use underwater structures of various types (see, for example, A. Lukoshkov, Seabed Research Technique. L. Sudostroenie, 1984, p. 154-167).

 Underwater drilling rigs are subject to a set of requirements for the placement of necessary equipment, supplies and maintenance personnel, ensuring strength, reliability, safety, and the supply of energy necessary for operation. The joint implementation of these requirements in the design of an underwater drilling rig is associated with significant design, technical and technological difficulties.

 Two types of subsea drilling rigs are known from the technical literature, which differ in the air pressure inside the body.

 The simplest are underwater drilling rigs with bell-type housings, inside which pressure equal to the outboard pressure is created, and drilling is carried out through the open bottom hatch. (See. Fig. 4.17. On page 162 of the aforementioned book: A. Lukoshkov. Technique for the study of the seabed. L. Shipbuilding, 1984). Due to the limitations of the possibility of a person in an air environment with high pressure, as well as certain difficulties in ensuring the operability of drilling equipment in these conditions, installations of this type are used when they are buried below the water surface by no more than 20-30 m.

 Underwater drilling rigs of a different type (see Fig. 4.18, p. 165, of the aforementioned book: Lukoshkov A.V. Technique for the study of the seabed. L.Sudostroenie, 1984) have a casing in which air pressure equal to atmospheric is constantly maintained and provided the most favorable conditions for the life of staff and the operation of drilling equipment prototype. However, for subsea drilling rigs of this type, it is difficult to create stuffing-preventer assemblies that would ensure the possibility of safe operation of service personnel and reliable sealing of the underwater rig body.

 The objective of the invention is to obtain a technical result, which consists in increasing the safety of drilling operations, making them possible in areas with severe hydrometeorological conditions, including those covered with ice, at depths of more than 30 m, as well as the use of drilling equipment and technology, widely tested in ground conditions.

 To do this, in a well-known underwater drilling rig, including a casing, inside which drilling equipment, supplies and maintenance personnel are located and having a hatch in the lower part of the casing, this casing hatch is connected to the seabed using a pipe filled with a “heavy” liquid with a specific gravity greater than near sea water for unloading the walls of the pipe from external hydrostatic pressure by balancing the pressure in the pipe and the environment.

где Н глубина моря в месте установки подводной буровой;
Δ Н глубина погружения подводной буровой под поверхность воды;
γ_в удельный вес воды в месте установки подводной буровой;
γ_ж удельный вес жидкости в трубе.Moreover, the specific gravity of the fluid filling the pipe is determined from the ratio
γ _w =

where N is the depth of the sea at the installation site of the underwater rig;
Δ N the depth of immersion of an underwater rig under the surface of the water
γ _{to the} specific gravity of water at the installation site of the underwater drilling rig;
γ _{W the} specific gravity of the fluid in the pipe.

В рассматриваемом случае в качестве сообщающихся сосудов выступает окружающая морская среда и труба, заполненная "тяжелой" жидкостью взаимодействующие через регулятор давления.The proposed solution is based on the use of the classical hydrostatic law of the law of communicating vessels, which states that in communicating vessels, the ratio of the height of the columns of liquids is inversely proportional to the ratio of the specific gravities of the liquids

In this case, the surrounding marine environment acts as communicating vessels and a pipe filled with a "heavy" liquid interacts through a pressure regulator.

 The connection of the open hatch with the seabed with a pipe filled with a “heavy” fluid and equipped with a pressure regulator in the lower part allows the underwater rig to be installed at a depth that excludes the influence of waves and floating ice while maintaining normal (atmospheric) pressure in the body of the drill, which in turn allows use of equipment of traditional ground type and comfortable working conditions for staff.

The present invention has the following significant distinctive features from the prototype features:
the hatch through which drilling is carried out is connected to the seabed by a pipe having a rigid or flexible structure;
the pipe connecting the hatch to the seafloor is filled with a liquid heavier than sea water, which ensures the depth of the rig by an amount excluding the influence of hydrometeorological, including ice, conditions;
drilling is performed through an open hatch at a pressure inside the rig body equal to atmospheric.

 Since these distinctive features from the prototype, the features are very significant, the present invention meets the criterion of inventive step.

 The proposal is illustrated in the drawing, which shows a diagram of an underwater drilling rig located on the seabed.

 The drilling rig comprises a housing 1 having an open hatch 2 connected to the bottom of a reservoir by a pipe 3, the cavity of which is partially filled with a “heavy” fluid to equalize the pressure in the environment and inside the pipe. Inside the pipe passes the drill string with drill pipes 4. The installation is positioned using the anchor system 5.

 The use of this proposal in the development of offshore hydrocarbon deposits will significantly simplify the design, increase the manufacturability and reduce the complexity of creating drilling tools, and use the existing capacities of converted shipbuilding enterprises for the manufacture of such installations without significant modernization.

Claims (1)

UNDERWATER DRILLING RIG, including a housing, inside which drilling equipment is located, rooms for maintenance personnel and stocks that ensure the life of the operating personnel and operation of drilling equipment, while the housing in the lower part has a hatch, characterized in that the hatch of the body is connected to the bottom of the reservoir by means of a pipe , the inner cavity of which is filled with a liquid with a specific gravity exceeding the specific gravity of water at the location of the underwater drilling rig and determined from the ratio

where H is the depth of the reservoir at the location of the underwater drilling rig, m;
ΔH distance from the surface of the water in the reservoir to the upper level of the liquid in the pipe, m;
γ _{W the} specific gravity of the liquid in the pipe, t / m ³ ;
γ _{in the} specific gravity of water at the location of the underwater drilling rig, t / m ³ .

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