The implementation of deepwater oil and gas projects is a vital task, the solution of which will help meet the growing demand for energy in the world.
More than 27 million barrels of oil per day were produced on the world shelf in 2015, and the share offshore fields accounted for 29% of total world oil production.
Experts’ forecasts note that the positive dynamics will continue, and the share of offshore fields in global oil production will continue to grow. Offshore fields are exploited in 50 countries around the world, but almost half of all production is concentrated in 5 leading countries: Saudi Arabia, Brazil, Mexico, Norway and the USA.
1. Saudi Arabia
The world leader in offshore oil production has several large oil fields, including Safaniya (Safaniya - Khafji) with oil reserves of about 10.35 billion tons and daily production in the region of 1.1 - 1.5 million barrels per day. More thanSafaniya field are not mined in any offshore field in the world.
State company Saudi Aramco invests enormous resources in support of the exploration and development program latest technologies production, the implementation of which was the fruit of cooperation between the latestResearch and Development Center (R&DC) and the best academic oil and gas institutes around the world.
The next Persian oil giant was the field Manifa ( video presentation of the project on the company website ), which took an honorable 5th place as the largest oil fields according to Bloomberg. The development of the field is carried out by a network of 27 artificial artificial islands and with the support of GiGaPOWERS technology (cartoon about the technology and history of Saudi Aramco ).
Video presentation of the Manifa project (Saudi Aramco)
We attach an article from Offhore-technology.com magazine:Saudi Arabia's offshore mega projects (English) for more detailed coverage of the issue.
2. Brazil
Oil production on the Brazilian shelf in the short period between 2005 and 2015 showed a 58% increase and at the end of 2015 ranked second in daily production among all countries in the world. This growth is largely due to the introduction into development of offshore fields in"sub-salt" zones e , the introduction of which will continue to have a positive impact on deep-sea oil production in the country.
Video about “pre-salt oil reserves” in Brazil
WITH according to data from GlobalData , Brazil intends to become a leader in offshore oil production in the near future, the number of projects just put into development is amazing: more than 40 projects will be put into operation by 2025 (236 are planned to be put into operation worldwide). Petroleo Brasileiro S.A (Petrobras - ) also leads in the number of planned projects - a total of 35 (34 - oil, 1 - gas), for comparison, the pursuers Petroleos Mexicanos and Chevron Corporation have 9 and 8 projects, respectively.
Brazilian reserves in the “sub-salt” zone are a tasty morsel for the world’s oil and gas giants. The government tried to strictly regulate their development by foreign corporations. Thus, until 2016, the development of deposits in the “sub-salt” zone on the shelf without 30% participation of the state company Petrobras was not allowed, but a series of political and corruption scandals coupled with the economic crisis both in the country and in Petrobras in particular led to the repeal of the law, making Brazil the focus of corporate news around the world(RIA NOVOSTI article “Brazil opens oil fields to foreign companies”) .
In particular, the oil and gas giant Royal Dutch Shell in As part of the new development strategy, it intends to focus its efforts on the liquefied natural gas and deep-sea oil production sectors. NowBrazilian deepwater production accounts for 13% of the corporation's total production of 1.8 million barrels per day. And Shell became the second largest hydrocarbon producer in the country after Petrobras (7.6% of Brazil's total production).
All Brazilian offshore projects in Halliburton infographics.
3. Mexico
Despite a significant decline in production from offshore assets (31% between 2005 and 2015), Mexico maintains third position in the ranking with 2 million barrels per day, representing 7% of global production.
The oil and gas industry in Mexico has been nationalized several times, but in 2013 a series of reforms ended the hegemony of the state monopoly PEMEX, giving the company a number of freedoms both administratively and economically. Yes, for the first time in for a long time, foreign companies took part in the bidding for 10 Mexican license areas: Shell, Chevron, ExxonMobil, BP, Total SA, Repsol, Statoil, Eni, Russian LUKOIL and, of course, Pemex itself.
The peculiarity of these auctions is that corporations unite into consortia and jointly bid for licensed areas. LUKOIL, in turn, cooperated with ENI and, unfortunately, lost. Read the results of the auction in the article in TECHNOBLOG magazine.
Reforms of the Mexican oil and gas industry
4. Norway
The Norwegian continental shelf includes the waters of the Northern, Norwegian and Barents seas. The main oil and gas activity is concentrated on the North Sea shelf; 60 oil and gas fields are currently being developed there. For comparison, there are 16 active projects in the Norwegian Sea, and only one in the Barents Sea (Shohvit). Complete map of the Norwegian Shelf fields:
In the period from 2005 to 2010, there was talk that time was running out for Norwegian oil (that period was marked by a 28% drop in production), but in 2010, due to the use of new technologies and the commissioning of new projects, oil production from offshore projects stabilized and amounted to 7% from global production (small increases in production are replaced by small drops).
Gas, condensate, LNG and oil production in Norway
To curb the rate of decline in production, enormous investments have been made, both in the development and search for new fields, and in the development of existing ones, in order to increase oil production and extend the life of the field. It is worth noting that investments in even a minor offshore project can be comparable to the largest projects on the shelf. mainland, huge amounts of money are being invested in exploration, field development, transport infrastructure and various supporting infrastructure facilities onshore.
Investments in offshore projects in Norway by year
- 3.84 MBDEVELOPMENT OF OFFSHORE FIELDS
Lecture No. 1. Introduction. Current state of development of offshore fields.
The gradual depletion of oil and gas reserves on land and the aggravation of the global energy crisis have necessitated the increasingly widespread development of oil and gas resources of the seabed in the depths of which almost 3 times are concentrated more oil and gas than on land.
About 22% of the area of the World Ocean (approximately 80.6 million km 2) is occupied by the watery margin of the continents, consisting of three zones: shelf, continental slope and foot. Of the total area of the seabed and oceans, about 75 million km 2 (approximately 21%) are promising for oil and gas, including 19.3 million km 2 on the shelf, 20.4 million km 2 on the continental slope and within continental foot -35 million km 2. The most accessible is the shelf zone.
The shelf (eng. Shelf) is understood as a leveled part of the underwater margin of the continents with a slight slope, adjacent to the land and characterized by a common geological structure with it. Depths at the outer boundary of the shelf are usually 100-200 m, but in some cases reach 1500-2000 m (South Kuril Basin Sea of Okhotsk). The width of the shelf ranges from 1 to 1700 km (Arctic Ocean), averaging 65-70 km, and the total area is about 32 million km 2 or almost 11.3% of the surface of the World Ocean. The main part of the shelf area of the World Ocean (approximately 70%) is located at depths not exceeding 180 m, and the sea depth in the area where the shelf transitions to the continental slope ranges from 200 to 600 m.
Figure 1 shows the profile of the continental shelf. The coastline 2 is followed by the continental shelf 3, beyond the edge 4 of which the continental slope 5 begins, descending into the depths of the sea. Behind the foot of slope 6 there is an area of sedimentary rock deposition, the so-called continental rise 7, the slope of which is less than that of the continental slope. Behind the continental rise, the deep-water plain part of the 8th sea begins.
Fig.2-Profile of the continental shelf.
The study showed that the depth of the shelf edge around the globe is approximately 120 m, the average slope of the continental shelf is 1.5-2 m per 1 km.
According to experts, over 60% of the shelf area is promising for oil and gas. At the same time, the predicted resources and reserves identified in gas and condensate fields prevail over the corresponding resources and reserves of oil.
The development of offshore fields began in 1824, when isolated offtakes - oil wells - began to be built on the shelf of the Absheron Peninsula in the Baku region, 25-30 m from the shore, and oil was scooped out from shallow horizons. Oil and gas fields in the coastal zone of the Caspian Sea began to be developed more than 100 years ago. Since 1891, areas of the sea began to be sold in the United States, at the bottom of which hydrocarbon reserves were discovered. During these same years, drilling of inclined wells began on the California coast, reaching neti deposits at a distance of 200 m from the coast. In 1936 on the shelf of the Caspian Sea, and since 1947. On the shelf of the Gulf of Mexico, drilling platforms began to be installed on pile foundations.
Currently, a fairly large number of drilling rigs of various types are operating on the shelf. About 1,000 exploration and approximately 2,000 production wells are drilled annually. In total, more than 100,000 wells have been drilled in the world.
Russia is currently on the threshold of industrial development of oil and gas reserves on the continental shelf. It has 22% of the shelf area of the World Ocean, 80-90% of which is considered promising for hydrocarbon production. About 85% of fuel and energy resources are on the shelf of the Arctic seas, 12%, and according to some data, 14% are on the shelf of the Far Eastern seas , and the rest to the shelves of the Caspian, Azov and Baltic seas.
The most promising water area in terms of hydrocarbon reserves is the Western Arctic, which includes the regions of the Barem, Red and Pechora seas. IN last years Large structures have been identified here and 10 oil and gas fields and 2 gas condensate fields have been discovered, among which 4 are gigantic in terms of reserves: Shtokman - gas condensate, Leningradskoye, Rusanovskoye - gas and Prirazlomnoye - oil.
World oil reserves are estimated at approximately 90 billion tons. The largest reserves of neti are located in Saudi Arabia, Kuwait, Iran, Iraq, the USA, and the United Arab Emirates. In Russia, oil was first produced in the Caucasus; later oil fields were discovered in the Volga region, Western Siberia, Teman-Pechora province, and Sakhalin. Now it’s time for Eastern Siberia and the continental shelf of the seas.
In the 40s XX century on the shelf of the Caspian Sea, oil and gas production began from artificial man-made islands, and then from metal overpasses, which ensured oil production from sea depths of 0.2 to 2.9 m. An entire city of drillers and oil and gas producers was created in the Caspian Sea – Oil Rocks.
The significant share of offshore oil and gas production in the global balance began to appear only in the 60s. XX century The growth of offshore oil production is currently more than 5 times higher than the growth rate of onshore production (Table 1).
Table 1
Share of offshore oil production in the global balance
The main oil and gas resources are also located in the Atlantic and Indian oceans. In the early 70s. Oil and gas production in the seas and oceans was carried out by 21 states, geophysical and drilling work was carried out by 46 countries and 5 were preparing for them. In the early 80s. more than 100 countries participated in the development of the continental shelf, 37 of them were developing offshore oil and gas fields. Searches for offshore deposits and their development in the early 90s. 136 companies and firms from 118 countries were already involved. During these years, oil and gas production on the continental shelf of the World Ocean reached 900 million tons of standard fuel (in terms of oil, where 1 ton of oil is equal to 1200 m 3 of gas) per year and amounted to about 35% of world production.
Currently, more than 120 countries are involved in the development of hydrocarbon resources on the continental shelf. About 2000 oil and gas fields have been identified on the shelves of seas and oceans, a significant part of which can be classified as giant or large (Fig. 2).
Fig.2 - Offshore oil and gas fields in the world (without Russia).
1-offshore production with a small number of wells; 2- industrial production zones; 3-promising mining areas.
The most oil and gas-rich areas of the continental shelf of the World Ocean are the Persian (more than half of the world's oil reserves), the Gulf of Mexico and Guinea, the seas of Southeast Asia, the Beaufort and North seas, and the Maracaibo sea lagoon (Venezuela).
They account for most of the continental shelf's oil and gas reserves. The world's largest offshore oil fields were discovered - Saffaniya with reserves estimated at 5 billion tons and with an annual flow rate of 75.5 million tons (Saudi Arabia); Maracaibo Lagoon with reserves exceeding 7 billion tons, and gas - North Dome with reserves of 71 trillion. m 3 (Qatar). Currently, offshore oil and gas production is expanding on an increasingly large scale in the Caribbean Sea, in the Gulf of Mexico, off the coast of Saudi Arabia and Kuwait, in the North and Norwegian Seas, on the shelf of Alaska and other offshore areas.
Control questions:
1. What is a shelf?
2. When did the development of offshore fields begin?
3. How many states are currently involved in the development of hydrocarbon resources on the continental shelf?
4. What zones does the watery margin of the continents consist of?
5.Which areas of the continental shelf of the World Ocean are the richest in hydrocarbons?
Lecture No. 2. Features of the development of offshore oil and gas fields.
Continental shelf, or continental shelf, in geological terms
Topographically, it is a continuation of the land towards the sea. This is the area around the continent from level low water to a depth at which the bottom slope changes sharply. The place where this happens is called the edge of the continental shelf. Usually the edge is conventionally located at a depth of 200m, but there are cases where a sharp increase in slope occurs at a depth of more than 400m or less than 130m. When the zone below low water is highly irregular and contains depths much greater than those typical of the continental shelf, the term "borderland" is used.
As experience in the development of oil and gas resources on the sea and ocean shelves shows, despite large capital investments, the extraction of hydrocarbons from offshore fields provides significant benefits. Profits from the sale of oil and gas produced on the shelf cover expenses by 4 times. Exploration costs in offshore areas range from 10 to 20% of the total costs for the development of offshore fields.
Total capital investments in the development of offshore oil and gas fields depend on climatic conditions, the depth and remoteness of the field from onshore service bases, the recoverable reserves of the field, well flow rates, and finally, on scientific and technological progress in the field of automation of the entire drilling process, arrangement of offshore fields, production, field collection, preparation and transportation of oil and gas in marine conditions.
The features of the development of offshore oil and gas fields include the following:
- creation, taking into account the harsh marine hydrometeorological conditions,6 special hydraulic structures of new floating technical means(floating crane installation vessels, service vessels, pipe-laying barges and other special vessels) for geophysical, geological prospecting work and the construction of oil field facilities at sea and their maintenance in the process of construction, drilling, operation and repair of wells, as well as during the collection and transportation of their products;
- drilling of inclined-directional well clusters from individual stationary platforms, from overpass platforms, on artificially created islands, from jack-up and semi-submersible floating installations and other structures both above and below water.
- selection when designing the most rational well grid for a given field or deposit, which should have such a density that no more compaction is required, since in offshore conditions it is associated with extremely great difficulties due to the already existing field development system and the network of underwater communications, when placement new hydraulic structures It may not be possible to drill additional wells.
- selection of rational designs and number of stationary platforms, trestle platforms, floating production decks and other structures for placing the optimal number of wells on them (depending on the occurrence of formations, timing of wells, the distance between their wellheads, their flow rates expected at the existing wellhead pressures, and etc.).
- compliance of the durability and reliability of hydraulic engineering and other structures with the timing of the development of oil and gas fields, i.e. the period of maximum oil extraction from the deposit and the entire field as a whole.
- Accelerating the construction of wells by creating reliable technology And advanced technology for drilling directional target wells with the necessary deviation from the vertical and ensuring the autonomy of the work of drilling crews (so that their work does not depend on hydrometeorological conditions of the sea) in the cramped conditions of platforms, overpass and other sites, which makes it possible to complete the drilling of all designed wells in a short period of time and only after this can we begin to develop them, eliminating the need for simultaneous drilling and operation of wells.
Factors complicating the development of offshore fields
There are many different factors that in one way or another complicate the development of natural hydrocarbon deposits and reduce its efficiency. The latter applies to oil fields to a much greater extent than to gas and gas condensate fields. The most important of these factors are:
- heterogeneity of reservoir properties along strike and across strike;
- unfavorable ratio of mobility of phases filtering in the formation;
- gravitational phase separation, leading to preferential filtration of gas along the upper part of the formation, and water along its lower part;
- formation of water and gas cones.
All these factors, manifested separately or together, lead to low macroscopic (i.e., manifested within the entire reservoir) coverage of formations by the influence and, as a consequence, to low oil recovery. Another factor influencing oil recovery is the efficiency of oil displacement by water. This factor is often called the microscopic coverage factor.
The formation of oil pillars (i.e. zones from which oil is practically not displaced) is often associated with the process of displacement of oil by water or gas from formations of heterogeneous permeability. This effect increases significantly in the case of displacement of high-viscosity oils, in which the unfavorable ratio of the mobilities of the displacing (water, gas) and displaced (oil) phases becomes more obvious. The heterogeneity of the formation in terms of permeability leads to the formation of so-called flood tongues, which, bypassing areas of the formation with low permeability, leave behind zones with oil saturation significantly higher than the residual, and therefore called pillars.
Formation of water and gas cones.
Under conditions of static equilibrium, i.e. Before the displacement process begins, gas, oil and water in the formations are distributed in accordance with their densities. If free gas is present, it is located in the upper part of the structure, forming a so-called gas cap, followed by an oil-saturated part of the formation or an oil zone underlain by bottom water.
During the production process, this balance is disrupted due to the creation of pressure gradients that take on especially high values in the bottomhole zone of production wells. The presence of high pressure gradients leads to a change in the shape of the conventional phase boundaries (i.e., water-oil and gas-oil contacts), causing them to bend towards the well perforations through which production is carried out. When pressure gradients (or the pressure difference between the well and the formation) exceed a certain level, a breakthrough of water and/or gas into the well may occur, as a result of which the oil flow rate may sharply decrease and gas and/or water production may become unreasonably high. Rice. 3 can serve as an illustration of a similar process of formation of a water cone.
Description of work
The gradual depletion of oil and gas reserves on land and the aggravation of the global energy crisis have necessitated the increasingly widespread development of oil and gas resources of the seabed, in the depths of which almost 3 times more oil and gas are concentrated than on land.
Oil production on the shelf is not as difficult a task as, say, exploring fields in Siberia. But for this purpose, expensive equipment is used, which extracts oil layers from the depths of the sea as much as possible.
The shelf is a deposit off the coast of seas and oceans, which often affect part of the coastal territory. The boundaries of the mining site are called the edge, which is a pronounced ledge of the depth difference. The depth of oil deposits can reach from 100 to 1500 m, depending on the location of the rocks. The hardest places to extract oil are on the shelves near New Zealand or in the waters of the Sea of Okhotsk.
Before choosing a production technology, researchers determine the depth of the oil layers and the geophysical features of the site. If the field is located in shallow water, then small fortified islands are constructed on which all equipment is installed. It is from this that drilling is carried out. This technology was developed more than 50 years ago, when they began to explore the Caspian region (in particular, the shelf near Baku). But special care is required here, since in cold waters the island can be damaged by ice. For example, in 1953, most of the wells were destroyed by a large floating ice floe. If there is such a threat, then large dams are installed and oil is pumped out in the pit.
If the field is located close enough to the shore, then the well is drilled from it, at a certain inclination. Sometimes they even make a horizontal well, which is easy to manage with the help of modern technologies. The accuracy of these devices is so high that you can accurately hit the oil layers directly from a control distance of several kilometers. ExxonMobil is still continuing to improve this technology, and today is considered a leader in this direction.
The complexity of production and the power of equipment depend on the depth of the field:
- 40 meters – stationary platforms are used;
- 80 meters – floating type drilling rigs;
- 150-200 meters – semi-submersible platforms, which are dynamically stabilized to avoid shifting from the production site;
- more than 200 meters - drilling ships that are used to extract oil from record-breaking wells. This method is most common in the Gulf of Mexico, where the depth of one well can reach 3 km.
The development of oil production on the shelves is a necessary measure, since 75% of the world's oil reserves are located there. The Arctic shelf, where more than 25% of total oil reserves are located, remains unexplored, but technologies for its extraction are still being developed.
1. The need for shelf development
According to the World Energy Council (WEC), by 2020, global energy consumption should double (from 12.5 to 24.7 billion tons), with oil accounting for 24.0%, gas -21% of total resources projected by 2020
At the same time, the world is provided with proven reserves for a period of about 50 years, while developed countries - up to 10 years (for gas, up to 65 years). To maintain the world's energy at the required level, the need to open new large oil and gas provinces is obvious.
To date, the land has been relatively explored and the likelihood of discovering large deposits is limited. Therefore, the main prospects for the discovery of new large deposits are associated with the shelf. These deposits are being developed recently, but already provide about 30% of world production. Geologists have established that shelf deposits, due to their good reservoir properties, provide good flow rates. Supergiant accumulations of hydrocarbons are the gas-oil field of Prudhoe Bay (Alaska), the gas-condensate field of Shtokmanoy (Barents Sea), the giant gas-condensate field of Leningradskoye and Rusakovskoye (Kara Sea).
Oil and gas production in offshore areas is carried out by 35 countries, at approximately 700 fields, including:
- 160 - in the North Sea;
- 150 - on the West African shelf;
- 115 - in Southeast Asia.
The volume of oil produced is about 1200 mt. (37% of world production), gas - 660 billion m 3 (28%).
According to the World Energy Council (WEC), by 2020, global energy consumption should double (from 12.5 to 24.7).
The depletion of shallow deposits will lead to the discovery of new ones at greater depths. Currently, there are 173 field development projects operating at depths (sea) of over 300 m. The projects determine that deepwater oil and gas production in the world in the coming years will require the drilling of 1,400 wells, more than 1,000 sets of underwater wellhead equipment, over 100 fixed and floating platforms . Offshore drilling is developed in the Gulf of Mexico, off the coast of West Africa, Brazil, and Norway.
Offshore drilling in different countries companies around the world:
- Norway - Statoil, Norsk Hydro, etc. work.
- UK - British Petroleum, Chevron, Conoco, Phillips, Shell, Statoil, etc.
- Nigeria - Chevron, Mobil, Shell, Statoil, etc.
- Malaysia - Exxon, Shell, etc.
2. Russian shelf: general characteristics.
45% of the hydrocarbon resources of the entire shelf of the World Ocean are concentrated on the shelf of the Russian seas.
All seas of the Russian Federation, except the White Sea, are promising for oil and gas. total area The Russian shelf zone is 6 million km 2 , of which about 4 million km 2 are promising for oil and gas.
More than 85% of total oil and gas resources are in the Arctic seas, 12% in the Far East and less than 3% in the Caspian Sea.
More than 60% are located at sea depths of less than 100 m, which is very important in terms of technical accessibility.
The initial recoverable resources of the shelf amount to 100 billion tce. incl. 16 billion tons of oil, 84 trillion m 3 of gas. Within many areas of the shelf, the continuation of oil areas from the coastal land (into the sea) can be traced. World experience shows that in this case the oil and gas content of the shelf is much higher than on the ground.
Abroad 30% c.e. mined on the continental shelf - This amounts to 700 million tons. oil and about 300 billion m 3 of gas. For comparison, in Russia in 1997, 350 units of oil were produced from onshore fields. tons, and about 700 billion m 3 of gas. By this time, not a single ton of oil or a single m3 of gas had been produced on the continental shelf.
The reasons for Russia's lag in the development of the sea shelf are due to the fact that until the 1970s, all work on the shelf was concentrated in the Caspian Sea (Azerbaijan), where 10-11 million tons of sea oil were produced and Russia produced a record amount of hydrocarbons on land , therefore, the state did not feel any particular need to launch large-scale work on the shelf.
But since the 1970s, with the decline in oil production, the country needed “oil” money. It was then that a decision was made to intensify work on the shelf of the Sea of Okhotsk, with the attraction of foreign investment, which marked the beginning of prospecting and exploration work on the Russian shelf.
Barencevo sea. Total potential reserves are 31.2 billion tons of standard fuel. The largest structures: the Shtokman gas condensate and Prirazlomnoye oil fields, as well as a group of fields in the Pechora Bay (Varandey Sea, Medynskoye Sea, North Dolginskoye, South Dolganskoye, West Matveevskoye, Russkoye). The following companies are taking part in the development of these fields: Gazprom, Rosshelf, Artikmorneftegazrazvedka, Wintershall, Conoco, Norsk Hydro, TotalFinaElf, Fortum.
Kara Sea. Total potential reserves - 22.8 billion t.e. The largest structures are the deposits of the Ob-Taz Bay (Leningradskoye, Rusanovskoye, Ledovoye). Exploration drilling has begun. The estimated start date of operation is 2007. The companies Gazprom, Rosshelf, and Artikmorneftegazrazvedka are involved in the work.
Laptev sea. Total reserves 3.2-8.7 billion t.e. The shelf has been studied very little; seismic exploration is underway.
East Siberian and Chukchi Sea. Total predicted resources -18 billion t.e. Three largest oil basins have been identified: Novosibirsk, North Chukotka and South Chukotka. Smaller basins include: Blagoveshchensky, Chaunxian: the shelf has been little studied.
Barencevo sea. Total resources - 1075 million t.e. There are three oil and gas basins: Anadyr, Khatyrsk and Navarin. Reconnaissance work is practically not carried out. The discovery of oil and gas fields is expected.
Okhotsk Mare and the Tatar Strait. Total recoverable resources are about 15 billion t.e. The main oil and gas basins: North-Sakhalin, West Kamchatka, Shelikhovsky, Magadan, Pogranichny, North-South Tatar, Schmidt, etc.
At the beginning of 2000, 173 promising structures had been identified, 31 objects had been prepared for exploratory drilling, and seven oil and gas fields had been discovered (mainly on the Sakhalin shelf). The companies Dalmorneftegorfieika, Rosneft, ExxonMobil, OGNC, Mitsui, Mitsubishi, Texaco, PGS, Hulliberton and others are participating in the development of the fields.
Caspian Sea.
- The total volume of reserves near the coast of the Astrakhan region is up to 2 billion tons. Largest structures: block "Northern", "Central", etc.;
- near the Dagestan coast reserves are up to 625 million tons of fuel equivalent, where the largest deposit is the Inchkhe Sea. Seismic exploration is underway;
- near the coast of Kalmykia the total reserves are up to 2 billion tons of oil. Oil companies involved in the development of fields are: Lukoil, Lukoil-Astrakhanmorneft, Gazprom, CanArgo, J.P. Redd et al.;
Black/Azov Sea. Rosneft is conducting exploratory drilling. Estimated gas reserves on the Azov Sea shelf are more than 320 billion m 3 .
Baltic Sea. Total proven reserves are 800 million tons of oil (Kraviovskoye Field). Exploration drilling led by NK Lukoil, oil production will begin in 2003.
The only structure where commercial oil and gas production is currently carried out in the Russian Federation is the Pnltun-Astokhskoye field (Sakhalin-2 project).
Exploration work is just beginning at Russian shelf fields. Competitions for licenses to develop offshore fields are mainly held on an “open” principle, i.e. the state does not limit the participation of foreign investors who are able to ensure an influx of capital investment into offshore projects.
For example: It is estimated that the total investment needs of the Sakhalin projects range from 21 (Sakhalin-2) to 71 billion dollars (Sakhalin-3) over 30 years.
Projects for developing the shelves of the Barents and Kara Seas may become even more capital-intensive. The development of offshore oil and gas fields in the Far North requires advanced equipment and technology, and most importantly, highly qualified specialists.
Offshore production
Offshore oil production
We are on a drilling platform - a complex technical structure designed for oil production on the sea shelf. Coastal deposits often continue on the underwater part of the continent, which is called the shelf. Its boundaries are the shore and the so-called edge - a clearly defined ledge, behind which the depth rapidly increases. Usually the depth of the sea above the edge is 100-200 meters, but sometimes it reaches 500 meters, and even up to one and a half kilometers, for example, in the southern part of the Sea of Okhotsk or off the coast of New Zealand.
Depending on the depth used various technologies. In shallow water, fortified “islands” are usually built, from which they carry out operations. This is how it has long been mined in the Caspian fields in the Baku region. The use of this method, especially in cold waters, often carries the risk of damaging oil-producing “islands.” floating ice. For example, in 1953, a large ice mass that broke away from the shore destroyed about half of the oil wells in the Caspian Sea. The technology is used less often when required area they are edged with dams and water is pumped out from the resulting pit. At sea depths of up to 30 meters, concrete and metal overpasses on which the equipment was placed. The overpass was connected to land or was an artificial island. Subsequently, this technology lost its relevance.
If the field is located close to land, it makes sense to drill an inclined well from the shore. One of the most interesting modern developments is remote control horizontal drilling. Specialists monitor the passage of the well from the shore. The accuracy of the process is so high that you can get to the desired point from a distance of several kilometers. In February 2008, Exxon Mobil Corporation set a world record for drilling such wells as part of the Sakhalin-1 project. The length of the well bore here was 11,680 meters. was carried out first in a vertical and then in a horizontal direction under the seabed at the Chaivo field, 8-11 kilometers from the coast.
The deeper the water, the more complex technologies apply. At depths of up to 40 meters, stationary platforms are built, but if the depth reaches 80 meters, floating drilling rigs equipped with supports are used. Semi-submersible platforms operate up to 150-200 meters, which are held in place using anchors or complex system dynamic stabilization. And drilling ships can drill at much greater sea depths. Most of the “record-breaking wells” were carried out in the Gulf of Mexico - more than 15 wells were drilled at a depth of more than one and a half kilometers. The absolute record for deepwater drilling was set in 2004, when Discoverer Deel Seas of Transocean and ChevronTexaco began drilling a well in the Gulf of Mexico (Alaminos Canyon Block 951) at a sea depth of 3053 meters.
In different difficult conditions In the northern seas, stationary platforms are more often built, which are held on the bottom due to the huge mass of the base. Hollow “pillars” rise up from the base, in which extracted oil or equipment can be stored. First, the structure is towed to its destination, flooded, and then, directly into the sea, the upper part is built on. The plant where such structures are built is comparable in area to a small city. Drilling rigs on large modern platforms can be moved to drill as many wells as needed. The task of designers of such platforms is to install a maximum of high-tech equipment in a minimum area, which makes this task similar to design spaceship. To cope with frost, ice, and high waves, drilling equipment can be installed directly at the bottom.
The development of these technologies is extremely important for our country, which has the most extensive continental shelf in the world. Most of it is located beyond the Arctic Circle, and the development of these harsh spaces is still very, very far away. According to forecasts, the Arctic shelf may contain up to 25% of global oil reserves.
- The Norwegian Troll-A platform, a striking representative of the family of large northern platforms, reaches 472 m in height and weighs 656,000 tons.
- Americans consider the date of the beginning of the offshore oil field to be 1896, and its pioneer is oilman Williams from California, who drilled wells from an embankment he built.
- In 1949, 42 km from the Absheron Peninsula, an entire village called Neftyanye Kamni was built on overpasses built to extract oil from the bottom of the Caspian Sea. Employees of the company lived there for weeks. The Oil Rocks overpass can be seen in one of the James Bond films - “The World Is Not Enough.”
- The need to maintain subsea equipment on drilling platforms has significantly influenced the development of deep-sea diving equipment.
- To quickly close a well in an emergency - for example, if a storm prevents the drilling ship from remaining in place - a type of plug called a "preventer" is used. The length of such preventers reaches 18 m, and their weight is 150 tons.
- The beginning of active development of the sea shelf was facilitated by the global oil crisis that erupted in the 70s of the last century. After the announcement of the embargo by countries, there was an urgent need for alternative sources oil supplies. Also, the development of the shelf was facilitated by the development of technologies, which by that time had reached such a level that would allow drilling at significant sea depths.
- The Groningen gas field, discovered off the coast of Holland in 1959, not only became the starting point for the development of the North Sea shelf, but also gave its name to a new economic term. Economists called the Groningen effect (or Dutch disease) a significant increase in the value of the national currency, which occurred as a result of increased gas exports and had a negative impact on other export-import industries.
A brief electronic reference book on basic oil and gas terms with a system of cross-references. - M.: Russian State University oil and gas named after. I. M. Gubkina. M.A. Mokhov, L.V. Igrevsky, E.S. Novik. 2004 .
See what “Offshore production” is in other dictionaries:
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