Offshore oil production, along with the development of shale and hard-to-recover hydrocarbon reserves, will eventually displace the development of traditional “black gold” deposits on land due to the depletion of the latter. At the same time, the production of raw materials in offshore areas is carried out mainly using expensive and labor-intensive methods, which involve the most complex technical complexes- oil platforms

Specifics of oil production at sea

The decline in reserves from traditional onshore oil fields has forced the industry's leading companies to focus on developing rich offshore blocks. Pronedra wrote earlier that the impetus for the development of this production segment was given in the seventies, after the OPEC countries imposed an oil embargo.

According to agreed estimates of experts, the estimated geological oil reserves located in the sedimentary layers of the seas and oceans reach 70% of the total world volumes and can amount to hundreds of billions of tons. Of this volume, about 60% falls on shelf areas.

To date, of the four hundred oil and gas basins in the world, half cover not only continents on land, but also extend on the shelf. Currently, about 350 deposits are being developed in different zones of the World Ocean. All of them are located within shelf areas, and production is carried out, as a rule, at a depth of up to 200 meters.

At the current stage of technology development, oil production in offshore areas is associated with high costs and technical difficulties, as well as a number of external unfavorable factors. Obstacles for efficient work at sea are often caused by high levels of seismicity, icebergs, ice fields, tsunamis, hurricanes and tornadoes, permafrost, strong currents and great depths.

The rapid development of offshore oil production is also hampered by the high cost of equipment and field development work. The amount of operating costs increases as the depth of extraction, the hardness and thickness of the rock increases, as well as the remoteness of the fishery from the coast and the complexity of the bottom topography between the extraction zone and the shore where the pipelines are laid. Serious costs are also associated with the implementation of measures to prevent oil leaks.

The cost of a drilling platform alone, designed to operate at depths of up to 45 meters, is $2 million. Equipment that is designed for depths of up to 320 meters can cost as much as $30 million. On average, the installation of an average production platform for production at great depths in the Gulf of Mexico costs at $113 million.

Loading of produced oil onto a tanker

Operation of a mobile type drilling platform at a depth of fifteen meters is estimated at $16 thousand per day, 40 meters - $21 thousand, a self-propelled platform when used at depths of 30-180 meters - at $1.5-7 million. The cost of developing fields at sea makes them profitable only in cases where large oil reserves are involved.

It should also be taken into account that the costs of oil production in different regions will be different. Work related to the discovery of a field in the Persian Gulf is estimated at $4 million, in the seas of Indonesia - $5 million, and in the North Sea prices rise to $11 million. The operator will also have to pay dearly for a license to develop an offshore field - he will have to pay twice as much as for permission to develop the land plot.

Types and structure of oil platforms

When extracting oil from the fields of the World Ocean, operating companies, as a rule, use special offshore platforms. The latter are engineering complexes with the help of which both drilling and direct extraction of hydrocarbons from under the seabed are carried out. The first oil platform to be used in coastal waters was launched in the US state of Louisiana in 1938. The world's first directly offshore platform called “Oil Rocks” was put into operation in 1949 in the Azerbaijani Caspian Sea.

Main types of platforms:

• stationary;
• loosely fixed;
• semi-submersible (exploration, drilling and production);
• jack-up drilling rigs;
• with stretched supports;
• floating oil storage tanks.

Floating drilling rig with outriggers "Arctic"

Different types of platforms can be found both in pure and in combined types. The choice of one or another type of platform is associated with specific tasks and conditions for field development. Usage different types platforms in the process of applying basic offshore production technologies we will consider below.

Structurally, an oil platform consists of four elements - a hull, an anchor system, a deck and a drilling derrick. The hull is a triangular or quadrangular pontoon mounted on six columns. The structure is kept afloat due to the fact that the pontoon is filled with air. The deck houses drill pipes, cranes and a helipad. The tower itself lowers the drill to the seabed and raises it as needed.

1 - drilling rig; 2 - helipad; 3 - anchor system; 4 - body; 5 - deck

The complex is held in place by an anchor system, including nine winches on the sides of the platform and steel cables. The weight of each anchor reaches 13 tons. Modern platforms are stabilized at a given point not only with the help of anchors and piles, but also with advanced technologies, including positioning systems. The platform can be moored in the same place for several years, regardless of weather conditions at sea.

The drill, whose operation is controlled by underwater robots, is assembled in sections. The length of one section, consisting of steel pipes, is 28 meters. Drills with quite wide capabilities are produced. For example, a drill on the EVA-4000 platform can include up to three hundred sections, which makes it possible to go 9.5 kilometers deep.

Oil platform drilling

The construction of drilling platforms is carried out by delivering the base of the structure to the production zone and flooding it. Already on the received “foundation” the remaining components are built on. The first oil platforms were created by welding lattice towers in the shape of a truncated pyramid from profiles and pipes, which were tightly nailed to the seabed with piles. Drilling equipment was installed on such structures.

Construction of the Troll oil platform

The need to develop fields in northern latitudes, where ice resistance of platforms is required, led engineers to a project for the construction of caisson foundations, which were actually artificial islands. The caisson is filled with ballast, usually sand. With its weight, the base is pressed to the bottom of the sea.

Stationary platform "Prirazlomnaya" with a caisson foundation

The gradual increase in the size of the platforms led to the need to revise their design, so developers from Kerr-McGee (USA) created a project for a floating object with the shape of a navigation pole. The design is a cylinder, in the lower part of which ballast is placed. The bottom of the cylinder is attached to the bottom anchors. This solution made it possible to build relatively reliable platforms of truly cyclopean dimensions, designed for work at extremely great depths.

Floating semi-submersible drilling rig "Polar Star"

However, it should be noted that there are no big differences in the actual procedures for extracting and loading oil between offshore and onshore drilling rigs. For example, the main components of a fixed platform offshore are identical to those of a drilling rig on land.

Offshore drilling rigs are characterized primarily by their autonomy. To achieve this quality, installations are equipped with powerful electric generators and water desalination units. Replenishment of platforms is carried out using service vessels. In addition, sea transport is also used to move structures to work points, in rescue and fire-fighting activities. Naturally, transportation of the obtained raw materials is carried out using pipelines, tankers or floating storage facilities.

Offshore technology

On modern stage development of the industry, inclined wells are drilled at short distances from the production site to the coast. At the same time, an advanced development is sometimes used - remote control of horizontal well drilling processes, which ensures high accuracy control and allows you to issue commands to drilling equipment at a distance of several kilometers.

The depths at the sea shelf boundary are usually about two hundred meters, but sometimes reach half a kilometer. Depending on the depth and distance from the coast, different technologies are used when drilling and extracting oil. In shallow areas, fortified foundations, a kind of artificial islands, are built. They serve as the basis for installing drilling equipment. In some cases, operating companies surround the work area with dams, after which water is pumped out from the resulting pit.

If the distance to the shore is hundreds of kilometers, then in this case a decision is made to build an oil platform. Stationary platforms, the simplest in design, can only be used at depths of several tens of meters; shallow water makes it possible to secure the structure using concrete blocks or piles.

Stationary platform LSP-1

At depths of about 80 meters, floating platforms with supports are used. Companies in deeper areas (up to 200 meters), where securing the platform is problematic, use semi-submersible drilling rigs. Such complexes are kept in place using a positioning system consisting of underwater propulsion systems and anchors. If we are talking about ultra-great depths, then in this case drilling ships are used.

Drilling ship Maersk Valiant

Wells are constructed using both single and cluster methods. IN Lately mobile drilling bases began to be used. Direct drilling at sea is carried out using risers - columns of large diameter pipes that descend to the bottom. After drilling is completed, a multi-ton blowout preventer (blowout prevention system) and wellhead fittings are installed at the bottom, which avoids oil leakage from the new well. Equipment to monitor the condition of the well is also launched. Oil is pumped to the surface after the start of production through flexible pipelines.

Application of different offshore production systems: 1 - inclined wells; 2 - stationary platforms; 3 - floating platforms with supports; 4 - semi-submersible platforms; 5 - drilling ships

The complexity and high-tech nature of the processes for developing offshore areas is obvious, even if you do not go into technical details. Is it advisable to develop this production segment, given the considerable associated difficulties? The answer is clear - yes. Despite the obstacles in the development of offshore blocks and the high costs compared to work on land, oil produced in the waters of the World Ocean is still in demand in conditions of continuous excess of demand over supply.

Let us recall that Russia and Asian countries plan to actively increase the capacities involved in offshore mining. This position can safely be considered practical - as the reserves of “black gold” on land are depleted, work at sea will become one of the main ways to obtain oil raw materials. Even taking into account the technological problems, cost and labor intensity of offshore production, oil extracted in this way not only became competitive, but has long since firmly occupied its niche in the industry market.

The special hydrometeorological conditions of the Arctic required special engineering solutions and technologies for the development of the Prirazlomnoye field. To implement the project, an offshore ice-resistant stationary platform (OIFP) “Prirazlomnaya” was created, which ensures the implementation of all technological operations: drilling wells, production, storage, preparation, loading of oil to tankers, generation of thermal and electrical energy. "Prirazlomnaya" is the world's first stationary platform from which they began to produce oil on the Arctic shelf in difficult conditions drifting ice fields. Currently, this is the only platform producing oil on the Russian Arctic shelf.

Below is an interactive 3D model of the Prirazlomnaya platform, which gives a clear idea of ​​what parts the platform consists of and how the first Russian Arctic oil is produced in general.

The platform is designed to operate in extreme climatic conditions, meets the most stringent safety requirements and is capable of withstanding maximum ice loads.

The length and width of the platform are 126 m, height – 141 m. The platform is securely held at the bottom of the sea due to its gravitational weight exceeding 500 thousand tons, and after installation it actually became an artificial island. Its gravitational stability and protection from soil erosion are also ensured by a crushed stone berm (its volume is over 45 thousand cubic meters), poured along the perimeter of the platform bottom. At the same time, the platform structurally consists of several parts: a caisson where the oil storage is located, an intermediate deck, an auxiliary module, a top structure, a residential module and two sets of direct oil loading devices (COUPON). More than 200 personnel work on the platform on a rotational basis every day, with shifts changing every 30 days.

Platform technical parameters

Round-the-clock monitoring of the condition of the Prirazlomnaya offshore ice-resistant platform is provided by a special system of more than 60 sensors that instantly respond to changes in its operation. Among such sensors:

• Inclinometer - for measuring caisson inclinations
• Strain sensor – for measuring ice loads
• Soil dynamometer - for measuring soil load
• Accelerometer - to monitor seismic activity around the platform
• Piezometer - for measuring pressure in soils from dynamic horizontal loads

Caisson control system

Oil (drilling) rigs are structures that are part of drilling stations. They are divided into mast and tower and are used for:

• SPO (trip and lift operations);
• support (on a tackle basis) of the drill string during drilling;
• placement of drill pipes removed from the well;
• location of the tackle system;
• placement of SPO and ASP mechanisms, platforms: working, emergency evacuation and auxiliary equipment;
• top drive location.

Russian oil rigs are built mainly at shipyards in Kaliningrad, Severodvinsk, Vyborg and Astrakhan. All drilling rigs are a complex complex, which is designed for drilling any wells, both on land and in the sea.

The first oil rigs in Russia were built in Kuban. And one of them produced a gush of oil, allowing the production of more than 190 tons per day.

Types of drilling

Drilling is divided into two types: horizontal and Horizontal drilling is a trenchless controlled method of laying communications underground using special drilling rigs. Drilling wells is a process of large and small diameters. The bottom is called the bottom, and the surface is called the mouth.

Drill string

The drill string is the main part of the oil rig structure. The column consists of:

The drill string itself is an assembly of special drill pipes that are lowered into the well. The pipes are designed to supply mechanical and hydraulic energy directly to the bit in order to create the necessary load on it and control the trajectory of the well.

Functions of the drilling rig

The oil rig performs the following functions:

• transmits rotation between the rotor and the bit;
• receives reactive torques from face motors;
• delivers flushing agent to the face;
• supplies power (hydraulic) to the engine and bit;
• presses the bit into the rock using gravity;
• ensures replacement of the engine and bit by transporting them to the bottom;
• allows for special and emergency work in the well itself.

Oil rig work

An oil derrick is designed for lowering and lifting into columns. At the same time, the tower allows you to support it in weight. Since the mass of such supporting elements is many tons, special equipment is used to reduce the load. Lifting equipment is one of the main components of any drilling rig.

The oil rig also performs a number of other works: it places a traveling system and other equipment in the drill string. When operating towers, the biggest danger is their complete or partial destruction. Most often, the main reason is insufficient supervision of the structure during operation.

The drill strings are lowered and raised several times. These operations are strictly systematic and consistent. Loads on the winch are cyclical. When lifting occurs, the power of the hook goes from the engine to the winch, when descending - vice versa. In order to use maximum power, multi-speed operating modes are used. During drilling and after its completion, the candles rise strictly at speed 1.

Types of drilling rigs

Oil rigs are divided into different types in height, design and load capacity. In addition to mast-type towers, tower towers are also used, assembled from top to bottom. Before assembly begins, a lift is mounted on the base of the tower. After complete installation it is dismantled.

Habitual structures

When installing an oil rig, conventional structures are always erected next to it, such as:

• gearbox;
• pump house;
• receiving bridge (inclined or horizontal);
• rock cleaning system;
• warehouses for bulk materials and chemicals;
• auxiliary structures during drilling (transformer sites, etc.);
• household facilities (canteen, dormitories, etc.);
• tackle system;
• winches;
• tools for unscrewing and making up BT.

Offshore oil rigs

The difference between an offshore drilling rig and a drilling rig located on land is the presence of water between the drilling rig and the wellhead. There are several ways to drill in offshore areas:

• from stationary offshore platforms;
• from gravity offshore platforms;
• from drilling jack-up rigs;
• from semi-submersible drilling rigs;
• from drilling ships.

An oil rig in the sea is a platform whose base rests on the bottom, and which itself rises above the sea. After the end of use, the platform remains in its place. Therefore, a water release platform is provided that isolates the well from water and connects the wellhead to the platform area. Wellhead equipment is installed at the MSP.

In order to tow the platform to the well, five tugs are used, with the participation of auxiliary vessels(escorts, tractors, etc.). An offshore gravity platform is a base made of steel and reinforced concrete. The oil rig is built in deep bays and transported by tugboats to desired point. It is designed for both drilling and storage until it is shipped. It is heavy, so no additional devices are required to hold it in place.

The jack-up rig has good buoyancy. It is installed on the bottom using lifting mechanisms to a height inaccessible to waves. After completion of operation, casing strings and liquidation bridges are used.

The semi-submersible installation consists of an equipped platform and pontoons connected by columns. The pontoons are filled with water and submerge the platform to the desired depth.

Self-lifting installations have good buoyancy and large body, which ensures towing immediately with the equipment installed on them. At a set point they are lowered to the bottom and immersed in the ground.

How to make an oil rig and what is it made of?

Drilling derricks are made from rolled profiles or used compressor pipes. They are made up to 28 meters high and with a carrying capacity of up to 75 tons. High towers are the most convenient, since lifting and lowering can be done not only by individuals, but also by knees, which significantly speeds up the work.

The distance between the lower legs of the tower and the upper part is approximately 8 meters. If the well is shallow, then masts will be required. Towers and masts are mounted on a strong foundation, which must be additionally strengthened with the help of anchors attached to it.

Crown blocks are installed on the towers, where the tackle system with a lifting hook is located. Working on oil rigs involves the installation of ladders that are installed for workers. They are made of metal or wood.

Drilling rigs

Oil and gas in the modern world are the main source of energy, as well as an indispensable raw material for products chemical industry. Of course, in addition to oil and gas, there are many other substances on Earth, but none of them can compare in production volume with these hydrocarbons.

However, to get them, you need to put in great amount effort. After all, currently oil does not lie directly on the surface, and extracting gas is even more difficult.

Drilling rigs and wells are an integral part of gas and oil production. These are the ones that will be discussed in this work. After all, knowing their structure and improving them can significantly increase production efficiency.

First, let's look at what a drilling rig is and what it is.

A drilling derrick is a structure that is part of a drilling rig, part of drilling equipment.

A drilling rig or drilling rig is a complex of drilling equipment and structures designed for drilling wells. The composition of the drilling rig components and their design are determined by the purpose of the well, the conditions and method of drilling.

1. carrying out hoisting operations (HLO);

2. maintaining the drill string on the tackle system when drilling with unloading;

3. placement of a set of drill pipes and drill collars (DCS) removed from the well;

4. placement of the tackle system;

5. placement of overhead mechanization means, in particular ASP mechanisms (may not be installed), upper worker platform, emergency evacuation device for upper worker, and auxiliary equipment;

6. placement of the top drive system (may not be installed).

The drilling derrick is equipped with flight ladders, a platform for servicing the crown block and a platform for the riding worker, which is designed for installing drill stands and ensures safety during tripping operations.

Types of drilling rigs.

There are towers:

· Tower

· Mast (A-shaped and U-shaped).

A-frame towers, consisting of two legs held vertically by struts or a gantry structure and guy ropes, are more labor-intensive to manufacture and therefore more expensive.

They are less stable, but they are easier to transport from place to place and then install.

The height of the drilling rig depends on the design depth of the well and ranges from 9 to 58 m. The main technical parameters of the drilling rig are height and lifting capacity.

Below are diagrams of A-frame and tower towers:

A-type mast tower: 1 - lifting stand; 2, 3, 4, 6 - mast section; 5 - fire escape; 7 - mounting trestles for repairing the crown block; 8 - crown block frame; 9, 10, 14 - stretch marks; 11 - guys; 12 - tunnel stairs; 13 - balcony; 15 - safety belt; 16 - flight stairs; 17 - hinge

The height of the tower determines the length of the candle that can be removed from the well and the length of which determines the duration of tripping operations. The longer the stand, the fewer parts it is necessary to disassemble the drill string when changing drilling tools. The time for subsequent column assembly is also reduced.

Tower tower. Tower VM1-41M: 1-strut; 2-leg base plate; 3-leg; 4-support shelf for jack; 5-transition platform; 6-flight staircase; 7-clamp; 8- scarf; 9-belt; 10-diagonal traction; 11-balcony; 12-crown block beam; 13- crown block platform; 14-goats

Therefore, with increasing drilling depth, the height and lifting capacity of the towers increase. Thus, for drilling wells to a depth of 300 to 500 m, a tower with a height of 16-18 m is used, a tower with a height of 42 m is used for a depth of 2000 to 3000 m, and a height of 53 m is used for a depth of 4000 to 6500 m.

The capacity of the “magazines” shows the total length of drill pipes with a diameter of 114-168 mm that can be placed in them. In practice, the capacity of the “magazines” shows to what depth drilling can be carried out using a particular tower.

The dimensions of the upper and lower foundations characterize the working conditions of the drilling crew, taking into account the placement of drilling equipment, drilling tools and means of mechanization of hoisting operations. The size of the upper base of the towers is 2x2 m or 2.6x2.6 m, the bottom 8x8 m or 10x10 m.

The lower and upper sections of the towers have base plates that secure them to the base with bolts. A crown block frame is installed on the slabs of the upper sections. Below, in the front side of the receiving walkway and in the rear edges above, there are gates 10.5-12 m high, consisting of two half-braces. Towers with a height of 41 m are equipped with one balcony, and those with a height of 53 m are equipped with two on the outer edges of the tower, which serve as shelter for the second pit during hoisting operations. On the balcony there is a cradle for the horseman to work and fingers for installing candles.

Based on the design of the main load-bearing elements, legs, belts, towers can be divided into:

· Pipe

· Profile rolled products.

Modern designs of pipe towers have a number of advantages over profile ones. Pipe ones have fewer bolted connections, they have less weight and the main elements of these are more resistant to deformation during transportation. Tower-type towers are a prefabricated metal structure in the shape of a truncated pyramid. The elements of the tower are thick-walled pipes, clamps and profile iron.

The most widely used pipe towers are type 2VB-53-320.

Legend:

Let's take a tower type VBA-53-32. Letters and numbers indicate: B - tower, B - tower, A - designed for the use of ASP mechanisms, 53 - height in m, 320 - load capacity on the hook in tons.

Mast (A-shaped, U-shaped) towers are made in separate sections, welded from pipes in the form of lattice trusses. In cross-section, the trusses have the form of an isosceles triangle (towers VM-40-185BR, VMA-41-170) or a rectangle. Each leg of the tower consists of 4 sections about 10 m long. At the ends of the sections there are flanges connected to each other with bolts or special quick-release clamps. The lower and upper sections have an eyelet. The upper section is hingedly connected to the crown block frame, which is the connecting link of the tower masts in the upper part. In addition, the masts of the upper part are hingedly connected to each other by two belts and two pairs of crosswise located screw ties. At the bottom of the mast, the towers are hingedly connected to the racks located on the substructure.

The stability of the tower in a vertical plane perpendicular to the plane of the trusses is ensured by two pipe struts. In the upper part, the struts are hingedly connected to the masts of the tower, and in the lower part - with supports installed on the base. To center the tower in a plane perpendicular to the plane of the trusses, the supports can be moved along the guides using screws. The tower is centered in the plane of the trusses using screw ties located in the upper part of the mast. In most cases, trestles or a transverse frame (portal) are used as an element supporting the tower in a vertical position.

The portal is mounted on substructures and attached to the masts of the tower legs using horizontal clamps. It is also used as a device for lifting the tower into a vertical position. A balcony with two cradles for the second pombur and fingers for installing candles, or a platform for the ASP candle placement mechanism and magazines for installing candles are attached to the tower masts at a certain height. One of the legs of the tower on the outer side from the rig floor to the balcony is equipped with flight stairs with transition platforms, and from the balcony to the crown block - tunnel-type stairs inside the section trusses. In some tower designs with rectangular masts, flight stairs and transition platforms are located inside the section trusses. To prevent candles from accidentally falling towards the receiving post or winch, safety belts are installed on the masts.

Mast-type towers have a number of advantages over tower towers: they require less metal to manufacture, they have fewer parts, which simplifies and speeds up assembly and disassembly. Open space between the masts makes it more convenient to carry out auxiliary work. According to the design and installation method, all mast towers are identical.

Metal drilling derricks have metal welded bases - skids and, with favorable terrain, can be transported over short distances without disassembly. The drilling building is transported separately if it is mounted on skids, or together with the tower (with a common base).

In rough terrain, towers are dismantled and transported in parts. The parts of the metal towers are connected with bolts, which ensures their quick assembly and disassembly. The main elements of the towers are seamless pipes, which, depending on the height of the tower, have diameters of 112/104 mm, 108/99.5 mm, 102/90 mm.

For the manufacture of belts, angle steel with dimensions of 65x65x6 mm and seamless pipes with a diameter of 73/67 mm are used, and for braces, angle steel 50x50x6 mm or flexible connections are used. The leg pipes are connected to each other by clamps to which they and the braces are attached. The legs of the tower have shoes for connection at the top with the frame, at the bottom with the base or foundation.

At the top of the tower there is a crown block platform.

Various towers produced in factories have minor differences in design.

For example, the VMR-24/540 tower has six standard sizes. The maximum load on the crown block for all sizes of these towers is 55 tons. The dimensions along the axes of the base supports are 6x6 m, along the axes of the crown block supports - 2x2 m. The main technical parameters of the towers are given in the table. 22.

In drilling practice, the following types of towers are also used: VU-18/25, VM-18/15, V-26-25, V-26/50, BM-32 - with a height from the lower base to the axis of the crown block, from 18 up to 32 m. The most widely used are collapsible towers of the VRM-24/540 and VM-18/15 types.

When installing a tower at a new point, it is necessary to take into account the prevailing wind direction and turn the tower edge-on to the wind, and also strengthen it with guy ropes with a diameter of 16 mm.

The Prirazlomnaya offshore ice-resistant stationary platform is a unique project of its kind. And uniqueness is known through comparison: “SN” assessed the advantages and disadvantages of offshore drilling rig designs

Infographics: Anna Simanova

1. “Prirazlomnaya”

Russia's first offshore ice-resistant stationary platform was built taking into account the natural and climatic conditions of the region. The OIRFP is held at the bottom of the sea, at a depth of 19.2 meters, due to its weight - 506 thousand tons. The erosion of the base of the platform is resisted by a stone berm - this is 120 thousand tons of stone and crushed stone poured around the OIRFP.

The safety margin of Prirazlomnaya exceeds possible loads - ice, anthropological and man-made

2. Regular platform

The drilling rig, production equipment, living quarters and auxiliary compartments are installed on steel (sometimes concrete) supports attached to the bottom. Such platforms are installed for long production periods at depths from 14 to 500 meters. Platforms on steel supports are not used in ice conditions.

The support piles of the stationary platforms are driven into the bottom and concreted. The piles of the first platforms were wooden

3. Flexible tower

Fixed platform with a multi-section flexible tower base. The underwater part is a light and narrow structure, tapering closer to the top. The flexible tower allows the platform to operate at significant depths; the movable structure compensates for the main part of the influence of wind and sea.

Most of the wave load on the base is absorbed due to the inertia of the structure and is not transferred to the platform itself

4. TLP Platform

The platform is held in the exact location of use by a system of tensioned cables. This type of attachment allows wellheads to be directly attached to wells using rigid pipes (risers). However, such platforms are not adapted to large ice loads, and also do not have their own oil storage.

The platform cannot be quickly detached from its anchors, making it dangerous to operate in polar conditions

5. SPAR type platform

Cylindrical subsea platforms are the largest offshore installations. Consists of a large cylinder that supports a typical rig superstructure. The cylindrical base is fixed afloat using cables and ropes and stabilizes the platform, taking into account its movements on the water.

Using a chain winch system, SPAR is able to move horizontally over the field area

6. Drilling ship

Designed specifically for deepwater drilling, although less stable than semi-submersible platforms. The anchor system allows the vessel to rotate around a vertical axis to compensate for gusts of wind. Some vessels can operate in polar conditions, but are highly dependent on ice conditions.

Drilling ships use “heave stabilizers”, which allow drilling wells in sea conditions of 5–6 points.