Oil platforms. Features of offshore oil and gas production. Onshore drilling platforms

Types of oil production offshore platforms

The stabilization of modern oil platforms in a given place is currently ensured not only by piles and anchors, but also by the use of advanced positioning technologies. The platform can remain moored at the same point for several years, and during this time it must withstand changing sea weather conditions.

The work of the drill, which destroys bottom rocks, is controlled by special underwater robots. The drill is assembled from separate steel pipe sections, each of which is 28 meters long. Modern drills have a wide range of capabilities. For example, a drill used on the EVA-4000 platform can consist of three hundred pipe sections, which allows drilling to a depth of up to 9.5 kilometers.

The construction of a drilling platform involves delivery to the site of the intended production and subsequent flooding of the base of the floating structure. On this kind of “foundation” the remaining necessary components are then built on.

Initially, such platforms were made by welding lattice towers, shaped like a truncated pyramid, from metal pipes and profiles, which were then firmly nailed with piles to the sea or ocean floor. The necessary drilling or production equipment was subsequently installed on such structures.

When the need arose to develop fields located in northern latitudes, ice-resistant platforms were required. This led to the fact that engineers developed projects for the construction of caisson foundations, which are actually artificial islands. Such a caisson itself is filled with ballast, which, as a rule, is sand. Such a base is pressed to the bottom of the sea under the influence of its own weight, which is acted upon by gravitational forces.

However, over time, the size of offshore floating structures began to increase, which made it necessary to reconsider the features of their designs. In this regard, the developers of the American company Kerr-McGee created a project for a floating object in the shape of a navigation pole. The structure itself is a cylinder, the lower part of which is filled with ballast.

The bottom of this cylinder is attached to the bottom using special bottom anchors. This technical solution made it possible to build fairly reliable platforms of truly gigantic dimensions, which are used for the extraction of oil and gas raw materials at extremely great depths.

To be fair, it should be said that there are no fundamental differences between the process of extracting hydrocarbons and its subsequent shipment between offshore and onshore production wells.

For example, the basic elements of a fixed offshore platform are the same as the basic elements of a land-based fishery.

The main feature of an offshore drilling rig is, first of all, the autonomy of its operation.

To achieve such autonomy, offshore drilling rigs are equipped with very powerful electric generators, as well as seawater desalinizers. Supplies on offshore platforms are renewed with the help of service vessels.

Also, the use of sea transport is necessary to deliver the entire structure to the production site, in the event of rescue and fire-fighting measures. Transportation of raw materials extracted from the seabed is carried out through bottom pipelines, as well as using a tanker fleet or through floating oil storage tanks.

Modern technologies, if the production site is located near the coast, involve drilling directional wells.

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If necessary, this technological process involves the use of advanced developments that allow remote control of drilling processes, which ensures high accuracy of the work performed. Such systems provide the operator with the ability to issue commands to drilling equipment even from a distance of several kilometers.

Mining depths on the sea shelf, as a rule, are within two hundred meters, in some cases reaching half a kilometer. The use of a particular drilling technology directly depends on the depth of the productive layer and the distance of the production site from the shore.

In shallow water areas, as a rule, reinforced foundations are erected, which are artificial islands on which drilling equipment is subsequently mounted. In some cases, in shallow waters, a technology is used that involves fencing the production site with a system of dams, which makes it possible to obtain a fenced pit from which water can then be pumped out.

In cases where the distance from the development site to the shore is a hundred or more kilometers, it is impossible to do without the use of a floating oil platform. The simplest in design are stationary platforms, but they can only be used at mining depths of several tens of meters, since in such shallow water it is possible to secure a stationary structure using piles or concrete blocks.

Starting from depths of about 80 meters, the use of floating platforms equipped with supports begins. In areas with great depths (up to 200 meters), securing the platform becomes problematic, so in such cases semi-submersible drilling rigs are used.

Such platforms are held in place using anchor systems and positioning systems, which are a whole complex of underwater engines and anchors. Drilling at ultra-great depths is carried out using specialized drilling vessels.

When constructing offshore wells, both single and cluster methods are used. In recent years, the use of so-called mobile drilling bases has begun to be practiced. The process of offshore drilling itself is carried out using risers, which are pipe strings of large diameters lowered to the very bottom.

After the drilling process is completed, a multi-ton preventer is placed on the bottom, which is a blowout prevention system, as well as wellhead valves. All this makes it possible to prevent leakage of extracted raw materials from a drilled well into open waters. In addition, control and measuring equipment must be installed and launched to monitor the current condition of the well. The lifting of oil to the surface is carried out using a system of flexible hoses.

As it becomes clear, the complexity and high level of technology of processes for the development of offshore fields are obvious (even without delving into the technical details of such processes). In this regard, the question arises: “Is such complex and costly oil production feasible?” Definitely yes. Here, the main factors speaking in its favor are the constantly growing demand for petroleum products with the gradual depletion of onshore fields. All this outweighs the cost and complexity of such mining, since raw materials are in demand and cover the costs of their extraction.

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Some interesting facts about offshore oil production

The largest oil platform in the world is considered to be a Norwegian platform located in the North Sea called Troll-A. Its height is 472 meters, and its total weight is 656 thousand tons.

In the United States, the date of the beginning of American offshore oil production is considered to be 1896, and its founder is a Californian oilman named Williams, who already in those years was drilling wells using an embankment he built with his own hands.

In 1949, at a distance of 42 kilometers from the Absheron Peninsula, on metal overpasses that were erected for oil production from the bottom of the Caspian Sea, an entire village was built, which was called “Oil Rocks”. In this village, people serving the work of the fishery lived for several weeks. This overpass (Oil Rocks) even appeared in one of the Bond films, which was called “The World Is Not Enough.”

With the advent of floating drilling platforms, there is a need to maintain their subsea equipment. In this regard, deep-sea diving equipment began to actively develop.

To quickly seal an oil well in the event of an emergency (for example, if a storm is raging with such force that the drilling vessel cannot be kept in place), a preventer is used, which is a kind of plug. The length of such a “plug” can reach up to 18 meters, and such a preventer can weigh up to 150 tons.

The main incentive for the development of offshore oil production was the global oil crisis of the 70s of the last century, provoked by the embargo imposed by OPEC countries on the supply of black gold to Western countries. Such restrictions forced American and European oil companies to look for alternative sources of petroleum feedstock. In addition, shelf development began to be more active with the advent of new technologies, which already at that time made it possible to carry out offshore drilling at great depths.

The development of offshore oil and gas fields required the creation of unique structures - offshore stationary platforms. Fixing on one point in the middle of the open sea is a very difficult task. And over the past decades, the most interesting solutions have been developed, without exaggeration, examples of engineering genius.

The history of oil workers going to sea began in Baku, on the Caspian Sea, and near Santa Barbara, California, on the Pacific Ocean. Both Russian and American oil workers tried to build a kind of piers that went several hundred meters into the sea in order to begin drilling fields already discovered on land. But the real breakthrough occurred in the late 1940s, when work began on the high seas, again near Baku and now in the Gulf of Mexico. The Americans are proud of the achievement of the Kerr-McGee company, which in 1947 drilled the first industrial well “out of sight of land,” that is, at a distance of approximately 17 km from the coast. The depth of the sea was small - only 6 meters.

However, the famous Guinness Book of Records considers the famous “Oil Rocks” (Neft Daslari - Azeri) near Baku to be the world's first oil production platform. Now this is a grandiose complex of platforms that has continued to function since 1949. It consists of 200 individual platforms and foundations and is a true city on the high seas.

In the 1950s, the construction of offshore platforms was underway, the base of which were lattice towers welded from metal pipes or profiles. Such structures were literally nailed to the seabed with special piles, which ensured their stability during rough seas. The structures themselves were quite “transparent” for passing waves. The shape of such a base resembles a truncated pyramid; in the bottom part, the diameter of such a structure can be twice as wide as in the top, on which the drilling platform itself is installed.

There are many designs of similar platforms. The USSR had its own developments, created on the basis of the experience of operating the Oil Rocks. For example, in 1976, the “Name of April 28” platform was installed at a depth of 84 meters. But still, the most famous platform of this type is Cognac in the Gulf of Mexico, installed for Shell in 1977 at a depth of 312 meters. For a long time this was a world record. The development of similar platforms for depths of 300-400 meters is still underway, but such structures cannot resist ice attacks, and special ice-resistant structures have been created to solve this problem.

In 1967, the largest American field, Prudhoe Bay, was discovered on the Arctic shelf of Alaska. It was necessary to develop stationary platforms that could withstand the ice load. Already at the early stages, two basic ideas appeared - the creation of large caisson platforms, essentially a kind of artificial islands that could withstand a pile of ice, or platforms on relatively thin legs that would let the ice through, cutting its fields with these legs. Such an example is the Dolly Varden platform, nailed to the seabed through its four steel legs, each of which has a diameter of just over 5 meters, despite the distance between the centers of the legs being almost 25 meters. The piles that secure the platform go into the ground to a depth of about 50 meters.

Examples of a caisson ice-resistant platform are the Prirazlomnaya platform in the Pechersk Sea and Molikpaq, also known as Piltun-Astokhskaya-A, on the shelf of Sakhalin Island. Molikpaq was designed and built to operate in the Beaufort Sea, and in 1998 she underwent reconstruction and began work in a new location. Molikpaq is a caisson filled with sand, which serves as ballast, pressing the bottom of the platform to the surface of the seabed. In fact, the bottom of the Molikpaq is a huge suction cup, consisting of several sections. This technology was successfully developed by Norwegian engineers during the development of deep-water fields in the North Sea.

The North Sea epic began in the early 70s, but at first oil workers managed quite well without exotic solutions - they built proven platforms from tubular trusses. New solutions were required when moving to great depths. The apotheosis of the construction of concrete platforms was the Troll A tower, installed at a depth of 303 meters. The base of the platform is a complex of reinforced concrete caissons that are suctioned to the seabed. Four legs grow from the base, which support the platform itself. The total height of this structure is 472 meters, and it is the tallest structure that has ever been moved in a horizontal plane. The secret here is that such a platform moves without barges - it only needs to be towed.

A certain analogue of the Troll is the ice-resistant platform Lunskaya-2, installed in 2006 on the Sakhalin shelf. Despite the fact that the sea depth there is only about 50 meters, it, unlike the Troll, must resist ice loads. The development of the platform and its construction were carried out by Norwegian, Russian and Finnish specialists. Its “sister” is the Berkut platform of the same type, which is installed at the Piltun-Astokhskoye field. Its technology complex, built by Samsung, is the largest facility of its kind in the world.

The 80s and 90s of the twentieth century were marked by the emergence of new constructive ideas for the development of deep-sea oil fields. At the same time, formally, the oil workers, crossing a 200-meter depth, went beyond the shelf and began to descend deeper along the continental slope. The cyclopean structures that would have stood on the seabed are approaching the limit of what is possible. And a new solution was again proposed by the Kerr-McGee company - to build a floating platform in the form of a navigation pole.

The idea is brilliantly simple. A cylinder of large diameter, sealed and very long is built. At the bottom of the cylinder is placed a load of material that has a specific gravity greater than that of water, such as sand. The result is a float with a center of gravity far below the water level. At its lower part, the Spar-type platform is attached with cables to bottom anchors - special anchors that are screwed into the seabed. The first platform of this type, called Neptune, was built in the Gulf of Mexico in 1996 at a depth of 590 meters. The length of the structure is more than 230 meters with a diameter of 22 meters. Today, the deepest platform of this type is the Perdido installation, operating for Shell, in the Gulf of Mexico at a depth of 2450 meters.

The development of offshore fields requires more and more new developments and technologies, not only in the actual construction of platforms, but also in terms of the infrastructure that serves them - such as pipelines, for example, which must have special properties for operation in offshore conditions. This process is underway in all developed countries that produce relevant products. In Russia, for example, Ural pipe makers from ChelPipe are actively developing the production of pipe products specifically designed for use on the shelf and in the difficult conditions of the Arctic. At the beginning of March, new developments were presented - such as large-diameter pipes for risers (riser columns connecting the platform with underwater equipment) and other structures that require durability in Arctic conditions. The work is being accelerated by the need for import substitution - more and more requests are being received from Russian companies for casing pipes and other equipment for constructing wells underwater. Technologies do not stand still, which means that opportunities are emerging for the development of new promising deposits.

We are making this publication for those who have always been interested in how an offshore drilling platform works and how this miracle of engineering works.

Types of offshore platforms:

• stationary oil platform;


• offshore oil platform, loosely fixed to the bottom;
• semi-submersible oil drilling platform;
  
  
  


• mobile offshore platform with retractable legs;
  
  
  


• drilling ship;
  
  
  


• floating oil storage facility (FSO) - a floating oil storage facility capable of storing oil or storing and loading it offshore;
  
  
  


• floating production, storage and offloading unit (FPSO) - a floating structure capable of storing, loading and producing oil;
  
  
  


• oil platform with stretched supports (floating base with tension vertical anchorage).

The four main components of an oil platform: the hull, the drill deck, the anchor system and the drilling derrick allow solving the problems of exploration and production of black gold in deep water conditions.

The hull is essentially a pontoon with a triangular or quadrangular base supported by huge columns. Above the hull is a drill deck that can support hundreds of tons of drill pipe, several cranes and a full-size helipad. A drilling rig rises above the drilling deck, the task of which is to lower/raise the drill to the seabed. At sea, the entire structure is held in place by an anchor system. Several winches pull tightly on steel mooring lines anchored to the ocean floor, holding the platform in place.

Principle of operation

The process of oil extraction begins with seismic exploration. At sea, seismic surveys are carried out using special ships, usually with a displacement of up to 3,000 tons. Such vessels unwind seismic streamers behind them, on which hydrophones (receiving devices) are located and create acoustic waves using a source of vibrations (air guns). Acoustic shock waves are reflected from the layers of the earth, and, returning to the surface, are captured by hydrophones. This data creates 2D and 3D seismic maps that reveal potential hydrocarbon reservoirs. However, no one can guarantee that he has found oil until it flows from the well.

So, after exploration, the drilling process begins. For drilling, the team assembles the drill in sections. Each section is 28 meters high and consists of iron pipes. For example, the EVA-4000 oil platform is capable of connecting a maximum of 300 sections, which allows it to go 9.5 km into the earth's crust. Sixty sections per hour, the speed at which the drill is lowered. After drilling, the drill is removed to seal the well to prevent oil from leaking into the sea. To do this, blowout prevention equipment or a preventer is lowered to the bottom, thanks to which not a single substance leaves the well. The preventer, 15 m high and weighing 27 tons, is equipped with control equipment. It acts like a huge bushing and can shut off the oil flow in 15 seconds.

When oil is found, the oil platform can be moved to another location to search for oil, and a floating production, storage and offloading (FPSO) unit will arrive to pump the oil out of the Earth and send it to refineries onshore.

An oil production platform can remain anchored for decades, regardless of any surprises from the sea. Its task is to extract oil and natural gas from the depths of the seabed, separating polluting elements and sending the oil and gas ashore.

Mining is carried out using special engineering structures - drilling platforms. They provide the necessary conditions for development to take place. The drilling platform can be set up at different depths - it depends on how deep the gas and gas deposits are.

Drilling on land

Oil occurs not only on land, but also in the continental plume, which is surrounded by water. That is why some installations are equipped with special elements that help them float on the water. Such a drilling platform is a monolithic structure that acts as a support for other elements. Installation of the structure is carried out in several stages:

• first, a test well is drilled, which is necessary to determine the location of the deposit; if there is a prospect of developing a specific zone, then further work is carried out;
• the site for the drilling rig is being prepared: for this, the surrounding area is leveled as much as possible;
• the foundation is poured, especially if the tower is heavy;
• The drilling tower and its other elements are assembled on the prepared base.

Deposit identification methods

Drilling platforms are the main structures on the basis of which oil and gas development is carried out both on land and on water. The construction of drilling platforms is carried out only after the presence of oil and gas in a particular region is determined. To do this, a well is drilled using different methods: rotary, rotary, turbine, volumetric, screw and many others.

The most common is the rotary method: when it is used, a rotating bit is driven into the rock. The popularity of this technology is explained by the ability of drilling to withstand significant loads for a long time.

Platform loads

A drilling platform can be very different in design, but it must be built competently, primarily taking into account safety indicators. If they are not taken care of, the consequences can be serious. For example, due to incorrect calculations, the installation may simply collapse, which will lead not only to financial losses, but also to the death of people. All loads that act on installations are:

• Constant: they mean forces acting throughout the operation of the platform. This includes the weight of the structures themselves above the installation, and water resistance if we are talking about offshore platforms.
• Temporary: such loads act on the structure under certain conditions. Only during startup of the installation is strong vibration observed.

Our country has developed different types of drilling platforms. To date, 8 stationary production systems are operating on the Russian plume.

Surface platforms

Oil can lie not only on land, but also under water. To extract it in such conditions, drilling platforms are used that are placed on floating structures. In this case, pontoons and self-propelled barges are used as floating means - this depends on the specific features of oil development. Offshore drilling platforms have certain design features, so they can float on the water. Depending on how deep the oil or gas is, different drilling rigs are used.

About 30% of oil is extracted from offshore fields, so wells are increasingly being built on water. Most often this is done in shallow water by fixing piles and installing platforms, towers, and the necessary equipment on them. Floating platforms are used to drill wells in deepwater areas. In some cases, dry drilling of water wells is performed, which is advisable for shallow openings up to 80 m.

Floating platform

Floating platforms are installed at a depth of 2-150 m and can be used in different conditions. Such structures can be compact in size and work in small rivers, or can be installed in the open sea. A floating drilling platform is an advantageous structure, since even with its small size it can pump out a large volume of oil or gas. This makes it possible to save on transport costs. Such a platform spends several days at sea, then returns to base to empty its tanks.

Stationary platform

A stationary offshore drilling platform is a structure that consists of a top structure and a supporting base. It is fixed in the ground. The design features of such systems are different, therefore the following types of stationary installations are distinguished:

• gravitational: the stability of these structures is ensured by the structure’s own weight and the weight of the ballast received;
• pile: they gain stability due to piles driven into the ground;
• mast: the stability of these structures is ensured by guy ropes or the required amount of buoyancy.

Depending on the depth at which oil and gas development is carried out, all stationary platforms are divided into several types:

• deep-sea on columns: the base of such installations is in contact with the bottom of the water area, and columns are used as supports;
• shallow-water platforms on columns: they have the same structure as deep-water systems;
• structural island: such a platform stands on a metal base;
• A monopod is a shallow-water platform on one support, made in the form of a tower and has vertical or inclined walls.

It is fixed platforms that account for the main production capacities, since they are more economically profitable and easier to install and operate. In a simplified version, such installations have a steel frame base, which acts as a supporting structure. But the use of stationary platforms must take into account the static nature and depth of the water in the drilling area.

Installations in which the base is made of reinforced concrete are laid on the bottom. They do not require additional fastenings. Such systems are used in shallow water fields.

Drilling barge

At sea it is carried out using the following types of mobile installations: jack-up, semi-submersible, drilling ships and barges. Barges are used in shallow-water fields, and there are several types of barges that can operate at very different depths: from 4 m to 5000 m.

A drilling platform in the form of a barge is used in the initial stages of field development, when it is necessary to drill wells in shallow water or protected areas. Such installations are used at the mouths of rivers, lakes, swamps, and canals at a depth of 2-5 m. Such barges are mostly non-self-propelled, so they cannot be used to carry out work in the open sea.

A drilling barge has three main components: an underwater submersible pontoon that is installed on the bottom, a surface platform with a working deck, and a structure that connects these two parts.

Self-elevating platform

Jack-up drilling platforms are similar to drilling barges, but the former are more modernized and advanced. They are raised on jack masts that rest on the bottom.

Structurally, such installations consist of 3-5 supports with shoes, which are lowered and pressed into the bottom during drilling operations. Such structures can be anchored, but supports are a safer mode of operation, since the body of the installation does not touch the surface of the water. The jack-up floating platform can operate at depths of up to 150 m.

This type of installation rises above the surface of the sea thanks to columns that rest on the ground. The upper deck of the pontoon is the place where the necessary technological equipment is installed. All self-lifting systems differ in the shape of the pontoon, the number of supporting columns, the shape of their section and design features. In most cases, the pontoon has a triangular or rectangular shape. The number of columns is 3-4, but in early projects the systems were created on 8 columns. The drilling derrick itself is either located on the upper deck or extends behind the stern.

Drilling ship

These drilling rigs are self-propelled and do not require towing to the site where work is being done. Such systems are designed specifically for installation at shallow depths, so they are not stable. Drilling ships are used for oil and gas exploration at depths of 200-3000 m and deeper. A drilling rig is placed on such a vessel, and drilling is performed directly through a technological hole in the deck itself.

At the same time, the vessel is equipped with all the necessary equipment so that it can be operated in any weather conditions. The anchor system allows you to ensure the proper level of stability on the water. After purification, the extracted oil is stored in special tanks in the hull and then reloaded into cargo tankers.

Semi-submersible installation

The semi-submersible oil drilling platform is one of the popular offshore drilling rigs as it can operate at depths of over 1500 m. Floating structures can submerge to significant depths. The installation is complemented by vertical and inclined braces and columns, which ensure the stability of the entire structure.

The upper body of such systems are living quarters, which are equipped with the latest technology and have the necessary supplies. The popularity of semi-submersible installations is explained by a variety of architectural options. They depend on the number of pontoons.

Semi-submersible installations have 3 types of draft: drilling, storm settling and transition. The buoyancy of the system is ensured by the supports, which also allow the installation to maintain a vertical position. Let us note that work on Russian drilling platforms is highly paid, but for this you need not only the appropriate education, but also extensive work experience.

conclusions

Thus, a drilling platform is an upgraded system of different types that can drill wells at different depths. The structures are widely used in the oil and gas industry. Each installation is assigned a specific task, so they differ in design features, functionality, processing volume, and resource transportation.

For the purpose of exploration or exploitation of mineral resources under the seabed.

Drilling platforms are mostly non-self-propelled, the permissible speed of their towing is 4-6 knots (with sea waves up to 3 points, winds 4-5 points). In the working position at the drilling point, drilling platforms can withstand the combined action of waves with wave heights of up to 15 m and wind speeds of up to 45 m/s. The operating weight of floating drilling platforms (with technological reserves of 1700-3000 tons) reaches 11,000-18,000 tons, the autonomy of work on ship and technological reserves is 30-90 days. The power of the drilling platform's power plants is 4-12 MW. Depending on the design and purpose, there are jack-up, semi-submersible, submersible, stationary drilling platforms and drilling ships. The most common are jack-up (47% of the total, 1981) and semi-submersible (33%) drilling platforms.

Self-elevating (Fig. 1) floating drilling platforms are used for drilling mainly at sea depths of 30-106 m. They are a displacement three- or four-legged pontoon with production equipment, raised above the sea surface using lifting and locking mechanisms to a height of 9-15 m. When towing, the pontoon with raised supports is afloat; At the drilling point, the supports are lowered. In modern self-elevating floating drilling platforms, the speed of ascent (lower) of the pontoon is 0.005-0.08 m/s, of the supports - 0.007-0.01 m/s; the total lifting capacity of the mechanisms is up to 10 thousand tons. Based on the method of lifting, there are walking-action lifts (mainly pneumatic and hydraulic) and continuous-action (electromechanical). The design of the supports makes it possible to place drilling platforms on the ground with a bearing capacity of at least 1400 kPa with a maximum depth of 15 m into the ground. The supports have a square, prismatic and spherical shape, are equipped with a gear rack along the entire length and end with a shoe.

Semi-submersible floating drilling platforms are used for drilling mainly at sea depths of 100-300 m and are a pontoon with production equipment raised above the sea surface (at a height of up to 15 m) with the help of 4 or more stabilizing columns that rest on underwater hulls ( 2 or more). Drilling platforms are transported to the drilling point on the lower hulls with a draft of 4-6 m. The floating drilling platform is submerged to 18-20 m by receiving water ballast into the lower hull. To hold semi-submersible drilling platforms, an eight-point anchor system is used, which ensures that the movement of the installation from the wellhead is limited to no more than 4% of the sea depth.

Submersible drilling platforms are used for drilling exploration or production wells at sea depths of up to 30 m. They are a pontoon with production equipment raised above the sea surface using square or cylindrical columns, the lower ends of which rest on a displacement pontoon or shoe, where ballast tanks are located. A submersible floating drilling platform rests on the ground (with a bearing capacity of at least 600 kPa) as a result of the ballast tanks of the displacement pontoon being filled with water.

Stationary offshore drilling platforms are used for drilling and operating a cluster of oil and gas wells at sea depths of up to 320 m. Up to 60 directional wells are drilled from one platform. Stationary drilling platforms are a structure in the form of a prism or a tetrahedral pyramid, rising above sea level (16-25 m) and resting on the bottom using piles driven into the bottom (frame drilling platforms) or foundation shoes (gravity drilling platforms). The surface part consists of a platform on which power, drilling and technological equipment, a residential block with a helipad and other equipment with a total weight of up to 15 thousand tons are located. The supporting block of frame drilling platforms is made in the form of a tubular metal lattice, consisting of 4-12 columns with a diameter 1-2.4 m. The block is secured using driven or drilled piles. Gravity platforms are made entirely of reinforced concrete or combined (metal supports, reinforced concrete shoes) and are supported by the mass of the structure. The foundations of the gravity drilling platform consist of 1-4 columns with a diameter of 5-10 m.

Stationary drilling platforms are designed for long-term (at least 25 years) operation in the open sea, and they are subject to high requirements for ensuring the presence of operating personnel, increased fire and explosion safety, corrosion protection, and environmental protection measures (see Offshore drilling) etc. A distinctive feature of stationary drilling platforms is their constant dynamism, i.e. For each field, its own project for equipping platforms with power, drilling and operational equipment is developed, while the design of the platform is determined by the conditions in the drilling area, drilling depth, and the number of wells, the number of drilling rigs.