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Floating oil platforms are operating in. The operating principle of an oil drilling rig. Construction of oil drilling rigs

The well-being of today's world and human civilization at this stage of its development is built on the widespread use of fuel resources. This is, first of all, oil, which is not only a relatively cheap source of energy, but is also used in many industries industrial production. An equally significant energy resource is natural gas.

Active development of these types of minerals began only in the 19th century. She became a consequence scientific and technological revolution, taking place in developed countries at this time. Traditional energy sources, which were coal, wood, and water steam, could no longer satisfy the industry growing at a gigantic pace. Oil became for many years a kind of foundation for human scientific and technological progress.

Nowadays, it has become noticeably more difficult to extract this resource, since most of the easily accessible deposits have already been exhausted. If you look at the map, the oil rigs are located extremely compactly in isolated areas. However, states and large companies develop and implement new technologies and methods of oil production. The development of offshore deposits looks especially promising in this regard. For this purpose, special production complexes are used - offshore oil platforms, which will be discussed later in the article.

What is an oil rig

The basic method of extracting the resources of the field is the construction and use of a special oil derrick, which is a special structure made, as a rule, from rolled steel profiles.

It is mounted above the well. Both drilling equipment for its construction and units for pumping out oil can be installed in the tower structure. Thus, these structures can be roughly divided into drilling and oil production (depending on their purpose).

Based on the type of construction, mast and tower towers are distinguished.

Mast.

Such structures are erected from several separate sections, which are lattice trusses. They are attached to each other using flange connections.

A special feature of this design are the “legs” of the tower, which themselves consist of 4 separate elements connected to each other. By the way, this type of construction is used in the popular game “Klondike”.

Tower.

This is a simpler design (compared to the mast one). It consists of only 4 “legs”, which are connected to each other and attached to a special base. This design, which was initially used everywhere, is not used so often due to lower reliability, but is inexpensive and easy to install. Oil rigs of this type in Russia are used on the shelf of the Caspian Sea.

In addition, it should be noted that towers can be land-based and sea-based. In the latter case, they act as an integral element of a larger structure - an oil platform.

Oil platform structure

Platforms that are being built for the extraction of hydrocarbon minerals from the sea shelf are complex and grandiose structures consisting of several parts.

The basis of the structure is the building on which other elements of this capital facility are located. At its core, it is a rather large pontoon, which, as a rule, has a rectangular shape.

To keep the platform body on the surface of the water and not sink, it is supported by special columns. They are filled with atmospheric air and have a significant displacement.

To ensure that the platform is stationary and not affected by sea currents, a special anchor system is used. She represents steel cables, which are attached on one side to winches located on the platform, and on the other to anchors located at the bottom of the sea. It should be noted here that increased attention is paid to the reliability of this element. So, the thickness of the cables alone is about 8 cm in diameter.

The next element of the oil platform is the drilling deck, which is fixed to its hull. There are also increased requirements for the strength of the materials from which it is made. This is not surprising, since the drilling platform must withstand enormous loads associated with the placement of drilling and oil production rigs on its surface.

The main structural element of an oil platform is the tower, the purpose of which was described above. It should be noted here that the height of the mast can reach tens of meters.

An oil platform is an expensive and technically complex engineering structure. In this regard, large companies organize security for drilling rigs to protect them from possible attacks and sabotage.

Construction stages

The oil platform is a prefabricated structure and is therefore being built in stages. So, first, its body and base are delivered to the area where oil production is planned, which is somewhat submerged and secured at the bottom using an anchor system. After this, the construction of the remaining superstructures begins. These include the drilling platform and towers, helipads, technical compartments, etc.

Previously, the construction of a platform consisted of driving piles into the bottom, to which individual structural elements were attached. But in the conditions of developing oil fields on the Arctic shelf, which involves working at great depths and unstable soils, they began to create caisson foundations filled with sand. Thus, oil production platforms in northern latitudes are artificial embankments and islands.

Operating principle

Oil deposits in the sea are searched using so-called seismic exploration methods, which are based on estimating the frequency of reflected sound waves.

When the field has been explored and geologists have provided data regarding its reserves, oil workers begin the drilling process. It is more complex than what happens on the surface of the earth, since the thickness of sea water creates additional mechanical resistance. After drilling is completed, equipment for oil pumping and production is installed. As reserves in individual formations are depleted, additional drilling work may be carried out at the field.

Types of offshore platforms

Depending on the purpose and functionality of oil production platforms, the following types are distinguished:

Stationary oil platform.

The most common type of oil and gas equipment, which allows both drilling and extraction of natural resources from the seabed at a depth of 15 to 500 m.

Mobile free-standing platform.

It is an oil platform, which, if necessary, can be easily moved to another location.

Semi-submerged oil platform.

Used for oil exploration.

The drilling rig is self-elevating.

A special type of oil and gas equipment, which is a drilling rig mounted on columns in the water column. Used in geological exploration.

Floating oil storage facility.

A multifunctional engineering complex that can be used for oil production, storage and transportation.

Offshore oil and gas production technologies

Extracting oil and gas from the seabed is a complex and expensive undertaking. To improve efficiency and reduce costs, engineers have developed several offshore oil and gas extraction methods that are used around the world. Their use depends directly on the depth from which the field is planned to be developed. There are several such technologies:

directional drilling – for coastal production;
stationary platforms on a rigid foundation – for mining at depths of up to 40 m;
standard floating platforms - for oil production at a depth of at least 80 m;
installation of semi-submersible platforms – at a depth of up to 200 m.

If the depth of the sea where the well is located is more than 200 m, then production is carried out by drilling ships using flexible pipelines.

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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 attached 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.

Operating principle

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 vibration source (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.

Oil rigs these are special metal structures that are mounted above equipped oil wells located on land or under water. They are designed for the design and operation of drilling equipment, as well as pumping out oil.

Depending on the functions they perform, oil rigs can be divided into drilling and oil production. In addition, they can be ground and surface-based, mobile and repair, cluster and stationary.

The drilling rig has a special design. For its installation, rolled profiles or used compressor pipes are used. Their height can reach 28 meters, depending on drilling conditions, and the load capacity of such a structure can be up to 75 tons.

The construction of taller towers is more expensive, however, they allow for kneeling rather than single ascent and descent, which significantly speeds up the operation of the tower. In addition, oil rigs are equipped with ladders so that the employees providing their work have free access to any part of the equipment.

Types of oil rigs

Oil rigscan be designed in two types:

Tower;
Mast.

Tower oil rigs

The tower requires the installation of four load-bearing legs for the structure, which are connected to each other in single network using a grid. At the same time, they take on the appearance of a tetrahedral pyramid with a truncated top. Their supports are mounted in the foundation or base, depending on the design features.

There are similar installations in Russia. They are installed in the Caspian Sea. Thanks to modern technologies, which allow the construction of complex and large-sized metal structures, they have less mass, but high resistance to deformation.

Mast oil rigs

Mast-mounted oil rigs are constructed in separate sections, which are welded pipes in the form of lattice trusses. In this case, the cross-section of each such truss has the form of a rectangle or an isosceles triangle. Moreover, each leg of this type of tower consists of four welded sections, the length of each of which is about 10 m.

The sections are connected using bolts that are attached to flanges located at the ends of the sections. In addition, quick-release clamps can be used for this.

New technologies for the construction of oil rigs at the exhibition

You can learn about all the new technologies that appear in the field of oil and gas development, including technology for the construction of oil rigs, by visiting the largest exhibition of this Oil and Gas industry, which takes place annually in Moscow on Krasnaya Presnya. For placement huge amount stands are used at the Expocentre Fairgrounds, as it is one of the largest and most technologically advanced exhibition centers in Russia.

This event is an excellent platform not only for studying the market situation and getting acquainted with new developments in various fields, but also for exchanging experience between specialists from different countries who come to Moscow to take part in exposition "Oil and Gas".

Considering that the scope of oil and gas development is increasingly shifting towards the north, where many large deposits, technologies that allow exploration and development in harsh Arctic conditions are becoming especially important. Due to the impossibility of developing most deposits, the process of development of the north is slowing down.

State this direction The development of the oil and gas industry is highlighted as a priority, since it is the export of this type of resource that is the main source of foreign exchange earnings to the budget of our country. That's why this issue so much attention is paid. Especially in conditions difficult relationships with the countries of the European Union and the USA.

If you want to learn about new technologies for constructing oil rigs, come to the exhibition!

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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 use of the most complex technical complexes - oil platforms

Specifics of oil production at sea

Reduction of stocks of traditional oil fields on land forced leading companies in the industry to devote their efforts to 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 fields are being developed in different zones 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 at great expense 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 size 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 license for the development of an offshore field will also be expensive for the operator - you 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 in both pure and combined forms. 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 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 that includes 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 anchored in the same place for several years, regardless of weather conditions in the sea.

A drill whose operation is controlled using underwater robots, is collected 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 rig

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 come up with 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. Besides, maritime transport It 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. In this case, an advanced development is sometimes used - remote control of the processes of drilling a horizontal well, which ensures high precision 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 of 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. Recently, mobile drilling bases have begun 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 helps to avoid 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 high costs compared to work on land, oil produced in the waters of the World Ocean is still in demand in the context of a continuous excess of demand over supply.

Let us remind you that Russia and Asian countries are planning to actively increase the capacities involved in offshore production. 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, the 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 development 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 the difficult conditions of 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 able to withstand 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 platform is provided by a special system of more than 60 sensors that instantly respond to changes in its operation. Among such sensors: