Where can you extract oil. How oil is extracted (methods) in the world and in Russia. Fountain method of oil production: the cheapest and easiest

Sending a person to explore outer space is much easier than extracting oil from the bowels of the earth. There is no strong pressure in space, the atmosphere of our planet is almost homogeneous, and, in the end, today, even through an ordinary one, everyone can see what is happening in the sky. But with oil, which is hidden underground, things are much more complicated.

Oil extraction in the past was a straightforward process. In some places, "black gold" erupted in fountains directly onto the earth's surface, and it could be immediately collected in containers. Later in the article, we will talk about how oil is produced, about such basic processes as preparation for development, drilling of wells and production management.

Increasing complexity and technology of oil production

In ancient Egypt, tinder was embalmed with the help of oil, in ancient India bitumen and asphalt were made from oil, in Byzantium, as historical sources testify, oil was already used as fuel for primitive flamethrowers installed on ships - this process was called "Greek fire".

Years, decades, centuries passed. Oil reserves, located in convenient places, were depleted, and humanity plunged headlong into the hydrocarbon phase, making the entire world economy dependent on the production of much-needed gas and oil.

Therefore, if someone from your environment enthusiastically talks about laptops and iPhones, you can only yawn and smile skeptically, because it is clearly clear that modern civilization is based not on gadgets, but on hydrocarbons.

It is not for nothing that oil is called "Black Gold" - this is 100% true. Oil is the basis of fuel for ships, aircraft, cars, and boilers are heated with fuel oil and gas.

People are everywhere surrounded by plastic things, and even in the medicine cabinet everyone has aspirin, which is synthesized from oil. Half a century ago, man had no choice but to learn how to extract oil from places that until recently were considered virtually inaccessible for commercial development. A significant contribution to the development of the “space technologies” necessary for oil production, which is pleasant to realize, was made by scientists and engineers of our country.

Where oil is produced in Russia — the leading company Gazpromneft-Khantos

In Russia, there is the operating Yuzhno-Priobskoye field of Gazpromneft-Khantos, a continuously developing oil enterprise, one of the main production subsidiaries of Gazprom Neft in Khanty-Mansi Autonomous Okrug-Yugra, which has been operating since 2005.

Today, the enterprise occupies a leading position among companies operating in Yugra in terms of oil production growth rates. If you wish, each of you can see this grandiose engineering miracle!

How much oil is left underground

I want to tell you the good news right away - there is a lot of oil underground. If you have tried a delicious layer cake at least once in your life, then it will not be difficult for you to visualize how our planet “looks inside”, and it consists of numerous layers of different rocks.

And this underground "pie" has an oil-bearing layer called the Bazhenov formation, covering an area of ​​​​a million square kilometers, which is located under western Siberia.

It contains a significant supply of oil, which allows for world consumption for a period of 15 to 30 years.

Oil production technologies and their lack of economic efficiency

And now a little about the sad. The technologies of mankind today are not yet sufficiently advanced for a full-scale and economically efficient development of the Bazhenov formation. In 2017, Gazprom Neft opened the Bazhen technology center in Khanty-Mansiysk, but now methods for commercial oil production from a group of these rocks are under development.

Despite the fact that the first test wells have begun to function, Gazprom Neft scientists still need a couple of years to bring production to a commercially profitable level, which is 2.5-4 million tons per year.

If we do not build far-reaching plans, then in the coming decades there is a reasonable hope to extract about 5% of the hydrocarbons occurring there for a full-fledged and economically efficient development of the Bazhenov formation.

How oil is produced using the example of Gazpromneft-Khantos

In order for you to have a clear idea of ​​what difficulties there are, we will tell you about how the Gazpromneft-Khantos enterprise operates, which currently produces about 15 million tons of oil equivalent annually. You need to imagine bricks that are soaked in oil, hidden underground at a depth of 3 kilometers. Bricks are pressed into a thin layer, 15-20 meters high, and other rocks frame it from above and below, like layers of a pie.

In order to gain access to these bricks, the oil workers set up a drilling site. The necessary point in the vicinity of Khanty-Mansiysk is designated by geologists, then a huge area isolated from water is poured out of the sand at this place. To give you a visual representation of the dimensions, these are approximately two football fields.

A sand bank is built around the site, and this is done in case of emergencies so that the oil does not leak anywhere. On the site itself, a monstrous drilling rig is assembled, which is a multi-storey building that moves from well to well along rails with a deafening roar.

Drilling begins, and as the drill moves deeper into the earth, the wellbore is reinforced with pipes. This is done so that the well does not collapse, and the drill itself, like a ramrod in a smoothbore gun, freely walks along the trunk. Between the rock and pipes, the free space is “plugged”, in other words, filled with cement. Of course, not everyone understands what the drill itself looks like.

This is in most cases an impressive-looking blank, made of very durable material. Drillers supply water to the shaft, which sets the drill in rotation, and then returns back along the walls of the shaft. The rotating drill deepens the well exactly in the direction that it is pointed from above.

Let's imagine that you are playing billiards, but you hit the metal balls, trying to drive them into the pockets, not with a cue, but with a jet of water from a water gun. But here, when extracting oil, you not only do not see the ball, but also are located at a great distance from it, reaching several kilometers. Russian drillers today solve approximately similar problems.

It will take several weeks to drill one well. As we said above, the drilling rig is on rails. After the work on the next well is completed, the drilling rig moves a few meters to drill the next well, then another and another, and the process continues until a whole “bush” of 12-18 wells appears.

Drilling of wells on the first kilometer is carried out more or less vertically, but in the future they smoothly turn in different directions, and practically flow into a horizontal plane, and as a result, the most real underground bush is obtained.

Thanks to this drilling technology, each pad collects oil from an underground platform with a radius of up to 4 kilometers.

Without an appropriate order, of course, high technologies cannot function. All objects are carefully monitored, so they are in perfect cleanliness, everything is exactly signed and badged.

How much do drillers get paid and what are their working hours?

All employees wear goggles and helmets, including superiors. Wage for ordinary drillers, the corresponding one is about 200 thousand rubles per month. After a month of work, the driller rests for a month.

This mode has both pros and cons. Among the advantages are the following:

• Power on high level. Quality like in a restaurant;
• Drillers are supplied with everything they need, so there are almost no costs. As a result, you can bring home an untouched salary;
• During the watch period, it is observed Labor Code. A shift worker works 12 hours per shift, he has all the social guarantees.

There are also cons:

• Weather conditions are quite severe - it is very cold here;
• If a person has a family, then such a “torn” schedule a month after a month is not suitable for everyone.

Of course, for a young employee without a family and children, such work is ideal. A high salary and a month of rest before the next shift allow you to have a good time and go on a trip.

Oil field development - preparation and drilling process

Let's talk again about how oil is produced at the stage of drilling a well. Many mistakenly assume that when the drill reaches the formation, a pipe can be connected and the oil pumped out. This is not true! To drill one vertical well, the company needs to shell out 35-45 million rubles. Theoretically, a metropolitan resident with good business, can sell a property located in the center and drill a powerful pipe down on his plot with a country house, but even if he is lucky enough to find at least a little oil in the bowels of the earth, he will not be able to “pull” it to the surface.

Let us once again focus on the fact that oil is contained in fairly dense layers. And by appearance they look like brick or sandstone soaked in oil. That is why the oil itself will not flow to you. For example, you pierce a pear with an awl - will pear juice flow out of it into a glass? Of course not. So it is with oil.

Geologists, in order to get oil, have to perform a truly jewelry operation, which is called hydraulic fracturing. How does this happen?

Under the strongest pressure, water is pumped into the well, which breaks the reservoir, forming cracks. Sand is driven into them, which prevents the cracks from closing back. Gazprom Neft has leading hydraulic fracturing technologies. In 2016, it was at the Gazpromneft-Khantos field that a record-breaking 30-stage hydraulic fracturing was carried out! After him, the bottom (lower end) of the well became like a brush with which we wash dishes.

But this is not the end of the work! In order for oil to go up, it needs to be pushed from below by water pressure. And here the geologists are faced with the task of making careful calculations indicating which wells need to be pumped into, and from which it is already possible to take oil going up to the drillers. As the oil is pumped out, the pressure in the reservoirs changes, so this is an ongoing workflow: water is injected into some wells, and pumps are lowered to the bottom of others, which “drive” oil to the surface under hellish pressure.

The monstrous pressure that accompanies oil production is a good reason to maintain order in the workplace and pay employees high wages.

For you to clearly understand, 200 atmospheres, modest in terms of oil parameters, is enough for even a thin stream to work like the sharpest scalpel. She is able to cut into pieces and expensive equipment and, God forbid, a blundered employee.

We draw attention to the fact that most of the equipment at the field is domestically produced with Cyrillic inscriptions unusual for a computer engineer and characteristic black nameplates.

It is pleasant to realize that our country is today a leader in the development of oil technologies.

So, let's put together all the work done:

• Wells were drilled;
• a complex of hydraulic fracturing was carried out;
• a complex system of vessels communicating under high pressure has been created;
• mine shafts were cleaned from foreign debris and sand.

Oil production management

Now oil has come to the surface, and then operators have joined the work. A few years ago, they had to go around all the wells in a circle and collect samples of formation fluid in bottles. These samples are a kind of whipped dark chocolate cocktail, and smell like gasoline from any gas station. Turning the valve, the operator pumped a foamy water-oil mixture into the bottle, and then sent a sound wave into the well using a special device. This was done to determine the current depth of the well. Until now, by the way, there is an interesting tradition for novice operators. After they have passed probation, the authorities coat them with reservoir fluid - this is a rite of passage into oilmen.

Today, the sandy area, which in summer resembles a scorched desert in the Arab countries, does not need to be visited often, since the wells are equipped with sensors. They take all readings in real time and then transmit them to the management center.

Until now, automation would have been limited to this - it is still more convenient to control all valves and devices from the control center than to run around the well pad, talking with operators on the radio. But modern realities stimulate oil companies be in constant development, because oil production is becoming more expensive year after year, but the effective demand for "black gold" is not growing as rapidly as one would like.

To exploit the field, you need to have a profitability of 15%, but, despite the modest-looking figures, it becomes more and more difficult to reach them every year.

Now oil companies are making digital twins for fields. All information flows to the Production Control Center (MCC), which is similar in arrangement to the Spacecraft Flight Control Center. Modern powerful computers simulate underground processes using neural networks and predict how much and what kind of oil each pump at each well should deliver to the surface, and what should be done to get the maximum result.

Of course, each of us can only roughly imagine what processes take place underground during oil production, how liquids move, how pumps work. In turn, the digital twin models everything extremely accurately, every minute correcting the three-dimensional picture with fresh sensor readings. The use of this system makes it possible to extract from the existing field to the maximum. And if, for example, people without equipment would produce 6 million tons per year, then computer equipment helps to almost double this figure - this is 10 million tons!

Well Logging - Dewaxing

There is an important nuance - the oil in the bowels of the earth has a temperature of 100-120 degrees, and this is enough for it to remain liquid. But as it is raised to the surface, it freezes, and when its temperature reaches 60 degrees, the paraffin, which is part of it, begins to settle on the walls of the mine. In order for this process not to interfere with oil production, a special round knife is periodically launched into the mine, which slides up and down and cuts paraffin from the walls.

In addition, there are a huge number of other devices in the mine that perform a specific task or transmit some important information to the oilmen. For example, "logging" is regularly carried out (the word comes from the French Carotte - carrot). During this process, geophysicists lower a probe that looks like a carrot into the wellbore, the task of which is to transfer to the surface detailed information about the rocks that surround the well.

Reservoir fluid and its separation

Reservoir fluid, which, as we said above, is a mixture of water, oil and, having come to the surface, goes through pipes into a small trailer resembling a spider. In it, the liquid is measured from different sides and sent further to the installation for the preliminary discharge of formation water.

Don't let the word "preliminary" mislead you, because in addition to wells, a real petrochemical plant operates at the oil field. Its main task is to prepare oil for travel through pipes. And so that you understand the scale of this plant, let's give an example. The operation of the Yuzhno-Priobskoye field requires 96 MW of electricity - this amount is enough to power a small city.

At the plant, reservoir fluid is placed in a huge separator, where it is separated into three large layers - associated gas, water and oil.

Associated gas is divided into two components - natural gas and NGL (broad hydrocarbon fraction). Natural gas, which is a mixture of ethane and methane, is used for heating and other household needs, including the generation of its own electricity, which saves serious amounts. NGL is pumped into a pipe and moved to a plant in Tobolsk, where propylene is also made from it. If earlier associated gas was simply flared, then recently the state made a change to the tax legislation and now it is more profitable to process gas.

The water is returned back to the wells and pumped underground to pressurize the system.

The remaining oil is subjected to even greater dehydration, salts are removed from it and purified from mechanical impurities, due to which clogging of the pipe may occur.

Oil laboratory

The local laboratory takes hundreds of samples every day to check the quality of the product, both at the entrance and at the exit. The laboratory is equipped not only with domestic equipment, which is approximately half. But the most important device - a threatening-looking tripod, placed in a brutal steel suitcase - was produced by a domestic manufacturer.

Many of you would be surprised to know that the cost of this portable device is 2.5 million rubles. But if it were bought abroad, the price could be ten times more.

Ecology of oil production

Let's get back to talking about oil production. When we talked about hydraulic fracturing, you probably imagined a post-apocalyptic landscape reminiscent of scenes from American films: dead trees, emaciated animals with two heads, cracked lifeless earth. But in fact, everything is different. Perhaps, in our country, fracturing is carried out at a greater depth, or more environmentally friendly chemicals are used, which allows us to leave the earth's surface in the mining area untouched. Near the wells there are ponds in which swans swim. If you come on a tour, then during the safety briefing, you will be told in detail where to run if the “bear has come” signal sounds. At the field, you will not feel the characteristic chemical smell.

Russia's leading position in oil production technology

You feel proud that in terms of production culture, we have certainly moved far ahead over the past twenty years. And if earlier the level of German and Japanese industry seemed unattainable to us, today our large manufacturing enterprises can boldly boast that responsibility and accuracy are their business card. Moreover, this level has been achieved not only in such high-tech industries as petrochemistry and oil production. Today, Russia has every right to be called a civilized industrial country and can teach many other countries with hydrocarbon reserves how to extract oil in conditions of its occurrence in deep layers.

Many people, as if even today, are in the dense past, thinking that extracting oil is as easy as shelling pears. Found a deposit, lowered the "pump" and pump! In fact, things are different, and oil production is a very high-tech process, which can perhaps be compared to the production of modern microprocessors. In fact, only a few states have the opportunity to develop complex deposits on their own. Russia is just such a state, and we can rightfully be proud of it.

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

Specificity of offshore oil production

The declining reserves of traditional onshore oil fields have forced the industry's leading companies to devote their energies to the development of 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 volume and can amount to hundreds of billions of tons. About 60% of this volume falls on shelf areas.

To date, half of the four hundred oil and gas basins of the world cover not only the continents on land, but also extend on the shelf. Now about 350 fields are being developed in different zones of the World Ocean. All of them are located within the 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, offshore oil production is associated with high costs and technical difficulties, as well as a number of external adverse factors. obstacles for effective work at sea, there is often a high seismicity rate, 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 works. The amount of operating costs increases as the depth of production, rock hardness and thickness increase, as well as the remoteness of the field from the coast and the complexity of the bottom topography between the extraction zone and the coast 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 up to 45 meters, is $2 million. Equipment that is designed for a depth of up to 320 meters can cost as much as $30 million. at $113 million

Shipment of produced oil to a tanker

The operation of a mobile 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 - $1.5–7 million. only in cases where we are talking about large oil reserves.

It should also be taken into account that the cost of oil production in different regions will be different. The work associated with 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. for permission to develop land.

Types and arrangement 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 hydrocarbon raw materials from under the seabed is carried out. The first offshore oil platform 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.

Main types of platforms:

• stationary;
• freely fixed;
• semi-submersible (exploration, drilling and production);
• jack-up drilling rigs;
• with extended supports;
• floating oil storages.

Floating drilling rig with retractable legs "Arctic"

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

Structurally, the oil platform consists of four elements - the hull, the anchor system, the deck and the drilling rig. 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. Drill pipes, cranes and a helipad are located on the deck. The tower directly 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, which includes nine winches along the sides of the platform and steel cables. The weight of each anchor reaches 13 tons. Modern platforms are stabilized at a given point not only with the help of anchors and piles, but also with advanced technologies, including positioning systems. The platform can be moored in the same place for several years, regardless of the weather conditions at sea.

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

Oil platform drilling rig

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

Construction of the Troll oil platform

The need to develop deposits in the northern latitudes, where ice-resistant platforms are required, led engineers to come up with a project to build coffered foundations, which actually were artificial islands. The caisson is filled with ballast, usually sand. With its weight, the foundation is pressed against the bottom of the sea.

Stationary platform "Prirazlomnaya" with a caisson base

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

Floating semi-submersible drilling rig "Polyarnaya Zvezda"

However, it should be noted that there is no big difference between offshore and onshore drilling rigs directly in the procedures for extracting and shipping oil. For example, the main components of a fixed type offshore platform are identical to those of an onshore oil rig.

Offshore drilling rigs are characterized primarily by autonomy of operation. To achieve this quality, the plants are equipped with powerful electric generators and water desalination plants. Replenishment of stocks of platforms is carried out with the help of service vessels. In addition, maritime transport is also used to move structures to work points, in rescue and firefighting activities. Naturally, the transportation of the received raw materials is carried out using pipelines, tankers or floating storage facilities.

Offshore technology

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

Depths at the sea boundary of the shelf are usually about two hundred meters, but sometimes reach up to half a kilometer. Depending on the depths and distance from the coast, different technologies are used for drilling and extracting oil. Fortified foundations, a kind of artificial islands, are being built in shallow areas. They serve as the basis for the installation of drilling equipment. In a number of cases, the operator companies encircle the work site with dams, after which water is pumped out of the resulting pit.

If the distance to the coast 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 fix the structure with 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 fixing the platform is problematic, use semi-submersible drilling rigs. The holding of such complexes in place is carried out using a positioning system consisting of underwater propulsion systems and anchors. If we are talking about super-great depths, then in this case drilling ships are involved.

Drilling ship Maersk Valiant

Wells are equipped with both single and cluster methods. Recently, mobile drilling bases have begun to be used. Direct drilling in the sea is carried out using risers - columns of large diameter pipes that sink to the bottom. After completion of drilling, a multi-ton preventer (blowout preventer) and wellhead fittings are installed at the bottom, which makes it possible to avoid oil leakage from a new well. The equipment for monitoring the state of the well is also launched. After the start of production, oil is pumped to the surface 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 technology of offshore development processes are obvious, even without going into technical details. Is it advisable to develop this production segment, given the considerable associated difficulties? The answer is unequivocal - yes. Despite the obstacles in the development of offshore blocks and the high costs in comparison with work on land, nevertheless, oil produced in the waters of the World Ocean is in demand in the conditions of an ongoing excess of demand over supply.

Recall that Russia and Asian countries are planning to actively increase the capacity involved in offshore production. Such a position can be safely 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 technological problems, the cost and labor intensity of offshore production, the oil extracted in this way has not only become competitive, but has long and firmly occupied its niche in the industry market.

In a charming magazine vl_ad_le_na I read a great post about oil production. I publish with the permission of the author.

What is oil?
Oil is a mixture of liquid hydrocarbons: paraffins, aromatics and others. In fact, oil is not always black - it can also be green (Devonian, I used to have it in a jar, sorry, I threw it away), brown (the most common) and even white (transparent, it seems to be found in the Caucasus).

Oil is divided by quality into several classes depending on chemical composition- accordingly, its price changes. Associated gas is very often dissolved in oil, which burns so brightly in flares.

Gas can be dissolved from 1 to 400 cubic meters in a cubic meter of oil. That is dofiga. This gas itself mainly consists of methane, but due to the difficulty of its preparation (it must be dried, purified and brought to GOST Wobbe numbers - so that there is a strictly defined calorific value), associated gas is very rarely used for domestic purposes. Roughly speaking, if gas from the field is put into an apartment in a gas stove, the consequences can be from soot on the ceiling to a fatally damaged stove and poisoning (for example, hydrogen sulfide).

Oh yes. Another associated muck in oil is dissolved hydrogen sulfide (because oil is organic matter). It is highly toxic and highly corrosive. This imposes its own difficulties on oil production. For oil production. Professionalism, which I, by the way, do not use.

Where did oil come from?
There are two theories on this (more details -). One is inorganic. It was first stated by Mendeleev and lies in the fact that water flowed past the hot metal carbides, and thus hydrocarbons were formed. The second is organic theory. It is believed that oil "matured", as a rule, in marine and lagoonal conditions, by decaying organic remains of animals and plants (silts) under certain thermobaric conditions (high pressure and temperature). In principle, research confirms this theory.

Why is geology needed?
It is probably worth mentioning the structure of our Earth. In my opinion, everything is beautiful and clear in the picture.

So, oil geologists deal only with the earth's crust. It consists of a crystalline basement (oil is found there very rarely, since these are igneous and metamorphic rocks) and a sedimentary cover. The sedimentary cover consists of sedimentary rocks, but I will not delve into geology. I will only say that the depths oil wells usually about 500 - 3500 m. It is at this depth that oil lies. Above is usually only water, below is a crystalline foundation. The deeper the rock, the earlier it was deposited, which is logical.

Where is the oil located?
Contrary to for some reason, widespread myths about "oil lakes" underground, oil is in traps. Simplifying, the traps in a vertical section look like this (water is the eternal companion of oil):

(The fold, curved "back" up, is called an anticline. And if it looks like a bowl - this is a syncline, oil does not linger in synclines).
Or like this:

And in plan they can be round or oval elevations. Dimensions - from hundreds of meters to hundreds of kilometers. One or more of these traps, located nearby, is an oil field.

Since oil is lighter than water, it floats up. But in order for the oil to not leak anywhere else (to the right, left, up or down), the reservoir with it must be limited by the rock-tire from above and below. Usually these are clays, dense carbonates or salts.

Where do the curves inside the earth's crust come from? After all, the rocks are deposited horizontally or almost horizontally? (if they are deposited in groups, then these groups are usually quickly leveled by wind and water). And bends - uplifts, lowerings - arise as a result of tectonics. Did you see the words "turbulent convection" in the picture with the cut of the Earth? This same convection moves the lithospheric plates, which leads to the formation of cracks in the plates, and consequently, displacement of blocks between cracks and changes in the internal structure of the Earth.

How is oil deposited?
Oil does not lie by itself, as already mentioned, there are no oil lakes. Oil is in the rock, namely, in its voids - pores and cracks:

The rocks are characterized by such properties as porosity is the fraction of the volume of voids in the rock - and permeability- the ability of the rock to pass through a liquid or gas. For example, ordinary sand is characterized by very high permeability. Concrete is much worse. But I dare to assure you that the rock lying at a depth of 2000 m with high pressure and temperature is much closer in properties to concrete than to sand. I felt. However, oil is being extracted from there.
This is a core - a drilled piece of rock. Dense sandstone. Depth is 1800 m. There is no oil in it.

Another important addition - nature does not tolerate emptiness. Almost all porous and permeable rocks are, as a rule, saturated with water; they have water in their pores. Salty because it flowed through many minerals. And it is logical that some of these minerals are carried away together with water in a dissolved form, and then, when the thermobaric conditions change, it falls out in these same pores. Thus, the grains of the rock become held together by salts and this process is called cementing. That is why, by and large, wells do not crumble immediately during the drilling process - because the rocks are cemented.

How is oil found?
Usually, first, according to seismic exploration: vibrations are started on the surface (by an explosion, for example) and the time of their return is measured by receivers.

Further, according to the wave return time, the depth of one or another horizon is calculated at different points on the surface and maps are built. If an uplift (=anticlinal trap) is detected on the map, it is checked for oil by drilling a well. Not all traps contain oil.

How are wells drilled?
A well is a vertical mine working with a length many times greater than its width.
Two facts about wells: 1. They are deep. 2. They are narrow. The average diameter of the well at the entrance to the reservoir is about 0.2-0.3 m. That is, a person will not crawl through there unambiguously. Average depth - as already mentioned, 500-3500 m.
Drilling wells from drilling rigs. There is such a tool for grinding rock as a chisel. Note, not a drill. And it is completely different from the same screw-shaped device from the Teenage Mutant Ninja Turtles.

The bit is suspended on the drill pipes and rotates - it is pressed to the bottom of the well by the weight of these same pipes. There are different principles for setting the bit in motion, but usually the entire drill string of pipes rotates so that the bit spins and crushes the rock with its teeth. Also, drilling fluid is constantly pumped into the well (inside the drill pipe) and pumped out (between the well wall and the outer wall of the pipe) in order to cool this entire structure and carry away particles of crushed rock with it.
What is the tower for? To hang these very drill pipes on it (after all, in the process of drilling, the upper end of the string is lowered, and new pipes must be screwed to it) and to raise the pipe string to replace the bit. Drilling one well takes about a month. Sometimes a special annular bit is used, which, when drilling, leaves a central column of rock - a core. The core is taken to study the properties of rocks, although this is expensive. Wells are also inclined and horizontal.

How to find out where which layer lies?
A person cannot go down into the well. But we need to know what we drilled there, don't we? When the well is drilled, geophysical probes are lowered into it on a cable. These probes work on completely different physical principles of operation - self-polarization, induction, resistance measurement, gamma radiation, neutron radiation, borehole diameter measurement, etc. All curves are written to files, it turns out such a nightmare:

Now the geophysicists are at work. Knowing the physical properties of each rock, they distinguish layers by lithology - sandstones, carbonates, clays - and perform a breakdown of the section according to stratigraphy (ie, to which era and time the layer belongs). I think everyone has heard about Jurassic Park:

In fact, there is a much more detailed division of the section into stages, horizons, members, etc. But we don't care now. It is important that oil reservoirs (formations capable of releasing oil) are of two types: carbonate (limestones, like chalk, for example) and terrigenous (sand, only cemented). Carbonates are CaCO3. Terrigenous - SiO2. This is if it's rude. It is impossible to say which is better, they are all different.

How is the well prepared for work?
After the well is drilled, it is cased. This means that a long string of steel casing pipes is lowered (almost like a well in diameter), and then ordinary cement mortar is pumped into the space between the well wall and the outer wall of the pipe. This is done so that the well does not crumble (after all, not all rocks are well cemented). In the context of the well now looks like this:

But we closed the formation we needed with a casing string and cement! Therefore, the perforation of the column is performed opposite the formation (and how to find out where the desired formation is? geophysics!). Again, a perforator with explosive charges embedded in it descends on a cable. There, the charges are triggered and holes and perforation channels are formed. Now we are not worried about water from neighboring layers - we perforated the well just opposite the one we needed.

How is oil produced?
The most interesting part, I think. Oil is much more viscous than water. I think that such viscosity is understandable intuitively. Some petroleum bitumens, for example, are similar in viscosity to butter.
I'll go from the other end. The fluids in the formation are under pressure - overlying rock layers push against them. And when we drill a well, nothing presses from the side of the well. That is, in the area of ​​the well, the pressure is reduced. A pressure drop is created, called depression, and it is this pressure that causes the oil to start flowing towards the well and appear in it.
To describe the flow of oil, there are two simple equations that all oilmen should know.
Darcy equation for rectilinear flow:

The Dupuis equation for a plane-radial flow (just the case of fluid inflow to the well):

In fact, we stand on them. It is not worth going further into physics and writing the equation of non-stationary inflow.
From a technical point of view, three methods of oil extraction are most common.
Fountain. This is when the reservoir pressure is very high, and oil does not just enter the well, but also rises to its very top and overflows (well, it doesn’t actually overflow, but further into the pipe).
Pumps SHGN (rod deep pump) and ESP (electric centrifugal pump). The first case is an ordinary rocking machine.

The second one is not visible at all:

Notice there are no towers. The tower is needed only for lowering / raising pipes in the well, but not for production.
The essence of the operation of the pumps is simple: the creation of additional pressure so that the fluid that enters the well can rise through the well to the surface of the earth.
It is worth remembering an ordinary glass of water. How do we drink from it? We tilt, right? But the well cannot be tilted. But you can put a straw into a glass of water and drink through it, drawing the liquid in your mouth. This is how the well works: its walls are the walls of the glass, and instead of a tube, a string of tubing (tubing) is lowered into the well. Oil rises through the pipes.

In the case of SRP, the pumping unit moves its "head" up and down, respectively, setting the bar in motion. When moving up, the boom pulls the pump with it (the bottom valve opens), and when moving down, the pump lowers (the top valve opens). So, little by little, the liquid rises up.
ESP works directly from electricity (with a motor, of course). Wheels (horizontal) spin inside the pump, they have slots, so oil rises to the top.

I must add that the open gushing of oil, which they like to show in cartoons, is not only an emergency, but also an environmental disaster and millions in fines.

What to do when oil is poorly produced?
Over time, oil ceases to be squeezed out of the rock under the weight of the overlying strata. Then the RPM system - reservoir pressure maintenance - comes into operation. Injection wells are drilled and water is pumped into them under high pressure. Naturally, the injected or formation water will sooner or later enter the production wells and will rise up along with the oil.
It should also be noted that the greater the proportion of oil in the flow, the faster it flows, and vice versa. Therefore, the more water flows with the oil, the harder it is for the oil to get out of the pores and into the well. The dependence of the proportion of oil permeability on the proportion of water in the flow is presented below and is called the relative phase permeability curves. It is also a very necessary concept for an oilman.

If the bottomhole formation zone is contaminated (with small rock particles carried away with oil, or solid paraffins have fallen out), then acid treatments are carried out (the well is stopped and a small amount of hydrochloric acid is pumped into it) - this process is good for carbonate formations, because they dissolve. And for terrigenous (sandstones) acid does not care. Therefore, hydraulic fracturing is carried out in them - gel is pumped into the well under very high pressure, so that the formation begins to crack in the well area, after which proppant is pumped (ceramic balls or coarse sand so that the crack does not close). After that, the well starts to work much better, because the obstacles to the flow are eliminated.

What happens to the oil after it is produced?
First, oil rises to the surface of the earth in a pipe that goes from each well. 10-15 nearby wells are connected by these pipes to one metering device, where it is measured how much oil is produced. Then the oil is sent for preparation according to GOST standards: salts, water, mechanical impurities (fine rock particles) are removed from it, if necessary, hydrogen sulfide, as well as oil, are completely degassed, to atmospheric pressure (you remember that oil can contain dofiga gas?). Marketable oil goes to the refinery. But the plant may be far away, and then the Transneft company comes into play - main pipelines for finished oil (as opposed to field pipelines for crude oil with water). Through the pipeline, oil is pumped by exactly the same ESPs, only laid on their side. The impellers rotate in them in the same way.
The water separated from the oil is pumped back into the reservoir, the gas is flared or goes to the gas processing plant. And oil is either sold (abroad by pipelines or tankers), or goes to an oil refinery, where it is distilled by heating: light fractions (gasoline, kerosene, naphtha) are used for fuel, heavy waxy fractions are used for raw materials for plastics, etc., and the heaviest fuel oils with a boiling point above 300 degrees usually serve as fuel for boilers.

How is all this regulated?
There are two main project documents for oil production: a reserve calculation project (there it is justified that there is just so much oil in the reservoir, and not more and not less) and a development project (the history of the field is described there and it is proved that it is necessary to develop it in this way, and not otherwise).
To calculate the reserves, geological models are built, and for the development project - hydrodynamic models (there it is calculated how the field will work in one mode or another).

How much does it all cost?
I must say right away that all prices are, as a rule, confidential. But I can roughly say: a well in Samara costs 30-100 million rubles. depending on depth. A ton of marketable (not processed) oil costs differently. When I counted the first diploma, they gave a value of about 3000 rubles, when the second - about 6000 rubles, the time difference is a year, but these may not be real values. Now I do not know. Taxes are at least 40% of profits, plus property tax (depending on the book value of the property), plus mineral extraction tax. Add the money required for workers' salaries, for electricity, for well repairs and field development - the construction of pipelines and equipment for collecting and processing oil. Very often, the economics of development projects goes into the red, so you need to contrive to work in the black.
I will add such a phenomenon as discounting - a ton of oil produced in next year, is less valuable than a ton of oil produced in it. Therefore, we need to intensify oil production (which also costs money).

So, I summarized what I studied for 6 years. The whole process, from the appearance of oil in the reservoir, exploration, drilling, production, processing and transportation to sale - you see that this requires specialists of completely different profiles. I hope that at least someone read this long post - and I cleared my conscience and dispelled at least a few myths surrounding oil.

Russia today has approximately 13% explored oil fields in the world. The main source of replenishment of the state budget of our country are deductions from the results of the oil and gas industry.

Oil-bearing layers are, as a rule, deep in the bowels of the earth. The accumulation of oil masses in the fields occurs in rocks with a porous structure, which are surrounded by denser layers. An example of a natural reservoir is a dome-shaped sandstone layer, blocked on all sides by layers of dense clay.

Not every explored deposit becomes an object of industrial development and production. Decisions on each are made only on the basis of a thorough business case.

The main indicator of the deposit- oil recovery factor, the ratio of the volume of oil underground to the volume that can be obtained for processing. A field suitable for development is a field with a predicted oil recovery factor of 30% and higher. With the improvement of production technologies in the field, this indicator is brought to 45% and above.

Underground storage always contains crude oil, natural gas and water at the same time under the enormous pressure of the layers of the earth's crust. The pressure parameter has a decisive influence on the choice of production method and technology.

Oil recovery methods

The method of oil production depends on the magnitude of the pressure in the reservoir and the way it is maintained. Three methods can be distinguished:

1. Primary– oil flows from the well due to the high pressure in the oil reservoir and does not require the creation of additional artificial pressure build-up, the oil recovery factor is 5-15%;
2. Secondary- when the natural pressure in the well drops and the rise of oil is not possible without additional pressure build-up due to the injection of water or natural / associated gas into the reservoir, the oil recovery factor is 35-45%;
3. Tertiary- increase in oil recovery from the reservoir after a decrease in its production by secondary methods, the oil recovery factor is 40 - 60%.

synthesis gas

Classification of mining methods

According to the principle of physical impact on a liquid oil body, today there are only two main methods of production: flowing and mechanized.

In turn, mechanized can be attributed gas lift and pump lifting methods.
If oil from the bowels is squeezed out to the ground only under the influence of the natural energy of the oil-bearing formation, then the extraction method is called a fountain.

But there always comes a moment when the energy reserves of the reservoir are depleted, and the well stops flowing. Then the rise is carried out using additional power equipment. This method of extraction is mechanized.

Mechanized way happens gas lift and pumping. In its turn gas lift can be carried out compressor and non-compressor method.

The pumping method is implemented through the use of powerful deep-well pumps: rod, electric centrifugal submersible.
Let's consider in more detail each method separately.

Fountain method of oil production: the cheapest and easiest

The development of new deposits is always carried out using the flowing method of production. This is the simplest, most efficient and cheapest method. It does not require additional energy resources and complex equipment, since the process of lifting the product to the surface occurs due to excess pressure in the oil deposit itself.

Main advantages

The main advantages of the fountain method:

• The simplest well equipment;
• Minimum cost of electricity;
• Flexibility in the management of pumping processes, up to the possibility of complete
  stops;
• Possibility remote control processes;
• Long intertechnological interval of equipment operation;

To operate a new well, you need to establish full control over it. The taming of the fountain is carried out by installing special shut-off valves, which subsequently allow you to control the flow, control the operating modes, make complete sealing, and, if necessary, conservation.
Wells equip lifting pipes of different diameters, depending on the estimated production rate and in-situ pressure.

With large production volumes and good pressure, large diameter pipes are used. Marginal wells for long-term preservation of the flowing process and reducing the cost of production, they are equipped with lifting pipes of small diameter.

By the way, read this article too: Features of heavy oil processing

Upon completion of the flowing process, artificial lift methods are being used at the well.

Gas lift method of oil production

Gas lift is one of the mechanized methods of oil production and a logical continuation of the flowing method. When the energy of the reservoir becomes insufficient to push the oil, the lift begins to be carried out by pumping into the reservoir compressed gas. This can be simple air or associated gas from a nearby field.

Used to compress gas high pressure compressors. This method is called compressor. The non-compressor gas lift method is carried out by supplying gas already under high pressure into the formation. Such gas is supplied from the nearest field.

The equipment of a gas-lift well is carried out by the method of completion of a flow well with the installation of special valves for supplying compressed gas at various depths with an interval established by the project.

Main advantages

Gas lift has its advantages over other artificial lift methods:

• sampling of significant volumes from different depths at any stage of field development with an acceptable cost indicator;
• the ability to produce even with significant curvature
  wells;
• work with heavily gassed and overheated formations;
• full control over all process parameters;
• automated control;
• high reliability of the equipment;
• operation of several layers simultaneously;
• controllability of paraffin and salt deposition processes;
• simple technology for maintenance and repair.

The main disadvantage of gas lift is high price metal equipment.
Low efficiency and high cost of equipment force the use of gas lift mainly only for lifting light oil with a high gas content.

Mechanized method of oil production - pumping

Pumping operation ensures the lifting of oil through the well with appropriate pumping equipment. Pumps are rod and rodless. Rodless - submersible type electric centrifugal.

The most common scheme for pumping oil sucker rod pumps. This is a relatively simple, reliable and inexpensive method. The depth available for this method is up to 2500 m. The productivity of one pump is up to 500 m3 per day.

By the way, read this article too: Equipment corrosion

The main structural elements are pump pipes and plungers suspended in them on rigid rod pushers. The reciprocating movement of the plungers is provided pumping unit above the well. The machine itself receives torque from the electric motor through a system of multi-stage gearboxes.

Due to the low reliability and performance of rod plunger pumps, submersible type pumping units are increasingly used in our time - electric centrifugal pumps (ESP).

Main advantages

Advantages of electric centrifugal pumps:

• ease of maintenance;
• very good performance of 1500 m3 per day;
• a solid overhaul period of up to one and a half years or more;
• the possibility of processing inclined wells;
• pump performance is regulated by the number of stages, total length
  assembly may vary.

Centrifugal pumps are well suited for old deposits with high water content.

For lifting heavy oil screw type pumps are best suited. Such pumps have great capabilities and increased reliability with high efficiency. One pump easily lifts 800 cubic meters of oil per day from a depth of up to three thousand meters. It has a low level of corrosion resistance in aggressive chemical environments.

Conclusion

Each of the technologies described above has the right to exist, and none of them can be said unequivocally whether it is good or bad. It all depends on the set of parameters that characterize a particular field. The choice of method can only be based on the results of careful economic research.

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Oil is called "black gold" because it is a hydrocarbon, without which the development of modern industrial production is unthinkable. Oil and gas is the basis of the fuel and energy complex, which produces fuel, lubricants, oil components are used in building materials, cosmetics, food, detergents. These raw materials are sold for currency and bring prosperity to countries and peoples that have huge reserves of it.

How are oil deposits found?

Mining begins with exploration of deposits. Geologists determine the possible occurrence of oil horizons in the bowels, first by external signs - the geography of the relief, the outcrops of oil slicks to the surface, the presence of traces of oil in groundwater. Experts know in which sedimentary basins the presence of oil reservoirs can be assumed, professionals are armed with various methods of exploration and prospecting, including surface study of rock outcrops and geophysical visualization of sections.

The presumable area of ​​occurrence of the deposit is determined by a combination of features. But even if they are all present, this does not mean that detailed exploration will reveal an oil pool with large reserves necessary to start commercial production. It often happens that exploratory drilling does not confirm the commercial value of the deposit. These risks are always present in oil exploration, but without them it is impossible to determine the structures (traps) in which oil accumulates in the amount necessary for development.