Technology drilling on shale oil. shale oil

Many people mistakenly believe that the shale gas is almost a separate energy carrier, but it received the prefix "shale" only because it lies in the shale layer of the sedimentary rock, and in its composition differs from natural gas by increased methane, carbon dioxide, ammonia and hydrogen sulfide. How is this source of fuel and the production of its production differs from traditional gas?

The main difference is the features of its location. The traditional gas is mined from porous reservoirs, the depth of which ranges from 700 to 4000 meters. Due to the large number of pores, collectors have high permeability (about 25%) and blue fuel easily pump out after the well is drilled.
The shale gas in turn listens at a depth of 2500 to 5000 meters in rocks with low porosity (3-4%), so its intelligence costs much more expensive, and the production technology is much more complicated.

Brief excursion in history

For the first time mining gas from the shale layer of sedimentary breed began almost 200 years ago. This happened in the USA in 1821. This type of fuel was used in the USSR: after the end of the Great Patriotic War, he was mined in Estonia and supplied on a gas pipeline to Leningrad. But soon the Soviet authorities, as well as the governments of many other countries of the world, realized that the production and transportation of shale gas costs much more expensive than the traditional natural, so the development of deposits was stopped.
The second life, the idea of \u200b\u200bmining of shale gas gained at the beginning of the two thousand years, when the technologies of horizontal drilling and multistage hydraulic fracturing began to be actively used, which allowed significantly to increase production volumes by reducing its cost.

Intelligence Technology

The search for deposits of shale gas requires much greater costs compared to the development of traditional blue fuel, and the exploration technology is far from perfection. Because of the high depth of the occurrence, many traditional research methods are ineffective.
If you look simplified, shale gas exploration occurs as follows:
In the alleged area of \u200b\u200bits location, the well is clogged in which hydraulic fracturing is carried out;
The gas obtained is analyzed, and on the basis of the analysis results, equipment and technology are determined that will need to be used for its production;
Well productivity is determined by the experimental way, and not with the help of accurate hydrodynamic studies, as in the extraction of ordinary natural gas.

World stock statistics

The predicted shale gas reserves are 760 trillion cubic meters, proven, according to the American Agency EIA, is 187.5 trillion cubic meters. For comparison, global gas reserves, according to the most readable magazine in the world in oil and gas topics, Oil & Gas Journal, make up just over 36 trillion barrels.
The largest deposits of shale gas possess KRN - 19.3% of world stocks, USA - 13%, Argentina - 11.7%, Mexico - 10.3%, South Africa - 7.3%, Australia - 6%, Canada - 5, 9%. These estimates may drastically change over time, because, as already mentioned, the exploration of shale gas reserves only begins to develop and so far well productivity is determined only by experimentally.

Drilling and gasket

A feature of the mining of shale gas is the technology of horizontal drilling. Its essence is that after one vertical well was drilled to the depth of deposits of shale gas, the bruis begins to go horizontally. However, there are many nuances that need to be observed during drilling, for example, it is necessary to ensure that the level of inclination of the borax corresponds to the angle of inclination of the shale formation and so on.
Mining companies are forced to apply such technology, as gas lies at a considerable depth in isolated pockets in very small volumes. Lifetime of wells is small - from 5 to 12 years. For reference, the life of the well of natural gas - from 30 to 50 years. On the largest developed SG field in the world - Barnettshale - the number of wells has already exceeded 17 thousand.
The horizontal length of the well can reach 12 kilometers (this record was installed during drilling on Sakhalin).
In a bored well, steel pipes are installed in several layers. Cement is poured into the space between them and the soil to isolate gas and fluid for the hydraulic fracturing of the soil formation, which contains water.

Hydraulic

Since the shale gas lies in a breed having a low porosity, it is impossible to extract it with traditional methods. That is why for mining of shale gas, the technology of hydraulic rupture of the formation (frenching) is actively used. Water, chemical reagents (ingibs of corrosion, thickeners, acids, biocides and many other chemical elements, the total number of which can reach 90 items) and special granules with a diameter of 0.5-1.5 millimeters can be supplied to the pipes for gas deposits From ceramics, steel, plastic or sand. This mixture creates a chemical reaction, which leads to the hydraulic frame. As a result, a lot of small cracks is formed in the breed that contains gas, in which the granules are stuck so that the cracks can no longer come together. Then water is pumped back (it is filtered and reused for the new GPU), and the shale gas, due to the pressure drop, rolls out through the pipes to the surface.

Fluids for hydraulic

The basis of the hydraulic fluid is water (98.5% of the total volume). About 1% of the composition - the "crushing" crack element (usually sand). The remaining 0.5% are chemical compounds affecting the water permeability of the breed. Without them, the hydraulic is simply impossible.
Over the past few years, many disputes about the harm for the ecology of liquids for hydraulic fracturing. The raised hype led to the fact that many European countries (France, Bulgaria, Italy) were forbidden to conduct hydrogenation on their territory, and in the United States, legislators have forced the company engaged in mining gas mining, publish information about the composition of the Fluids for hydraulic gas.
But the technology of hydraulic, and, accordingly, liquids for them are used and used in the extraction of ordinary natural gas. For example, it actively applies Rosneft, which produced two thousand hydraulic persons a few years ago.

Transportation and cleaning

It is impossible to deliver shale gas in conventional ways to end users, since standard gas pipelines are calculated for pressure in 75 atmospheres. In the shale gas, this figure is much lower due to the elevated content of ammonia, hydrogen sulfide, nitrogen and carbon dioxide and when pumping it through gas pipelines for natural gas, an explosion may occur.
There are two solutions to the problem of transportation: to take the cleaning factories, which will make it possible to make the composition of shale gas close to natural and then deliver it to existing gas pipelines, or create a separate infrastructure for transporting shale gas.
The first option requires significant costs and makes the mining of shale gas simply unprofitable. But the second method is increasingly actively used by shale fuel countries. Moreover, they all prefer to deliver gas for small distances to consumers who are close to the field, which makes the transportation of shale gas as cheap.
This is exactly what is done in the USA, where the mined gas is transported so far only on short local low pressure gas pipelines or pumps into cylinders. China, which began the construction of the first shale gas pipeline to the province of Yunnan, the length of which is only 93 kilometers. This concerns the transportation of shale gas to long distances, then in the absence of an extensive network of gas pipelines, the most promising method is currently transformation in special terminals. In liquefied gas and sending to buyers with tankers. Upon arrival at the destination, the product is pumped into storage tanks, and then converted back to the gaseous state and is delivered by gas pipelines to end users. At the moment, the construction of such terminals is actively engaged in the United States. The first object through which fuel exports to the countries of Southeast Asia will be carried out, it is planned to be commissioned at the end of 2015. All terminals built by 2020 are expected to export 118 billion cubic meters of shale gas.

The main know-how of modern mining

Environmental harm can be minimized by applying propane fakeigning technology. It differs from the usual hydraulic dispenser by the fact that instead of water and chemicals, a propane, unlike traditional hydraulic fluids, is injected to places of shale gas, which, unlike traditional hydraulic fluids, is not settled in the soil after hydraulic, and it does not completely evaporate, so it cannot .
This technology has seriously changed the attitude of many European countries caring for their ecology to carry out hydropraits. The British authorities have already removed the ban on the FSC, other EU countries only consider this opportunity.
True, propane frequin has a significant minus, crossing all his praise ecology. The use of this method is one and a half times more expensive than the usual hydraulic dispenser. Therefore, it is possible to use such technology only on deposits having a high profitability.

The shale is called the stone widely used as a building and finishing material. However, some shale varieties found their widespread use in the energy sector. Slate can be used in the production of quartz graphite, garnet, paper, as well as as a source of magnesium and silicon. Depending on the conditions of education, shale are divided into:

• clay;
• aspine;
• crystalline;
• coaliest;
• chlorite;
• combustible;
• veld;
• talc and others.

Formed at sufficiently large depths under conditions of high pressure and temperature, claders have a crystal structure that has clearly pronounced layers.

In connection with such a demand, shale mining is conducted in many countries, including Mexico, USA, Colombia, Venezuela, New Guinea, Russia, North Africa, etc.

In many countries, shale deposits are used as a source for oil and gas production.

Mining shale oil

Shale oil is customary to be called oil, the main source for the production of which is the shale deposits, which are in solid or liquid state and formed for quite a long time with vegetable and animals residues.

Such oil is in the formation of rock for which low density and permeability is characteristic. In addition, a breed containing shale oil also has a huge amount of impurities, which are called oil sands or severe bituminous oil. Processing such a product is a very expensive procedure, as a result of which the material is formed several times more expensive than ordinary oil. This is due to the fact that the technology of shale mining is still imperfect and only its initial stage of development passes. In this regard, today shale oil is more promising reserve for the future and in no way can affect the existing oil market.

Despite the high cost of the product, shale oil continues to be mined. There are two methods that enjoy the advantage during the production of this product:

1. Open (shaft) method. In this case, the breed after withdrawal from earthly decraces falls on further processing into special installation-reactors. These installations are used for shale pyrolysis without air access. This process leads to a shale resin. It is worth noting that the open method is characterized by its high cost and, accordingly, expensive end product.
2. Mining from a formation by hydraulic rupture (or frenching). With this method, horizontal wells are clogged, and multiple hydraulic plates are produced. Often, before this, there is a need for thermal or chemical heating of the reservoir. Despite the high cost of the open production of shale oil, this method is even more complex, and, accordingly, more expensive.

In addition, during the extraction of shale to receive oil, a major way arises a serious problem, which consists in a very rapid fall of the flow-down wells. If at the very beginning of the well, the wells are characterized by a sufficiently high flow rate, which is associated with horizontal injection and multiple hydraulic swaps, after 400 working days there is a sharp drop in the amount of raw materials produced (up to 80%). In order to avoid such a situation during shale mining, the introduction of wells is carried out in stages.

It is worth noting that shale deposits contain a sufficiently low gas concentration. It is going, as a rule, in collectors who are scattered in all the thicker of the breed. Thus, each separate collector contains a very small amount of gas. But, if they are all collected together, then even very large stocks are obtained.

Shale gas is mined in several ways:

1. Horizontal drilling. The basis of this method is the use of special drilling rigs. This method is most common and is considered priority during shale gas extraction.
2. Hydraulic reservoirs. The essence of the method is to create a high-level crack in the target formation in order to highlight shale gas from it. This method is used when ordinary methods are already ineffective.
3. Seismic modeling. This method combines geological studies with mapping and computer processing, including visualization.

It is worth noting that today there are modern technologies for mining of shale gas, under which a special drilling rig, containing one vertical well and several horizontal, whose length can be about 3 km. Wells are filled with a special mixture, which includes water, sand and chemical agents, due to which it occurs. As a result, gas collectors are damaged and the gas contained in them is released and pumped out.

When mining shale gas, as in the development of standard gas fields, variable pressure areas are created. Thus, the gas moves depending on the pressure. For this purpose, horizontal wells are used that have several taps at one depth. Also permissible formation of multistage wells having a horizontal removal of 2 km long.

The greatest experience in the development of shale deposits is characteristic of the United States. So, it shows that each separate such deposit has its own unique geological parameters that affect the operation and production of material. Thus, in each case, an individual scientific approach is needed during gas production.

Table 1. Differences of shale and natural gas

Shale gas	Natural gas
Extracted from sedimentary rocks	It is extracted from gas-bearing deposits, gas "caps" of oil fields, gas hydrates
Mining involves drilling wells with horizontal sections using a fracturing of the formation (less often - propane frequency)	Production according to the most common scheme involves drilling vertical wells without hydraulic reservoir
Prey Most often involves drilling a few hundred wells at one field	Mining involves drilling, as a rule, several tens of wells at one field
One well resource - 1-2 years	Resource of one well - 5-10 years
As a rule, requires a sufficiently deep processing after extracting in order to bring consumer standards	Usually requires minimal processing after extracting
Characterized by relatively high production cost	Characterized by relatively low production cost

Consequences of shale prey

Greenpeace has been agitation for the cessation of shale gas production and shale oil over the years. This is due to the fact that during shale production, hazardous and poorly studied hydraulic ruptures are used. As a result of environmental research, a number of factors were identified, which are evidence of shale mining negatively affects human and the environment. These include:

1. Water pollution. The hydraulic rupture of the reservoir entails pollution with toxic chemicals of groundwater, as well as sources of drinking water. With frenching, colossal volumes of water are used, which is a danger to regions suffering from drought and water deficit.
2. Air pollution. During shale mining, methane and other gases are allocated to the atmosphere. Sometimes pollution is so strong that residents living near places where slates are mined are forced to wear respirators.
3. Soil pollution. Toxic fluids used in mining of shale can penetrate the soil.
4. Land use. Shale mining entails a strong destruction of the landscape, as a result of which harm and agricultural grounds are also applied. On the territory of 140-400 km 2, about 3000 wells are formed.
5. Noise pollution. Refers, mainly to Frequo. Damits to local residents, home and wild animals.
6. Seismic activity. Disposal of polluted water is carried out by pumping it under the ground, which significantly increases the risk of earthquakes.
7. Changing of the climate. Greenhouse gases that are thrown into the atmosphere in the process of shale mining, many times higher than the amount of greenhouse gases released during the extraction of traditional minerals. A lot of studies have been conducted on this subject, as a result of which scientists came to the conclusion that during the extraction of shale gas, methane leakage occurs, three times higher than its leakage during the extraction of natural gas.
8. Socio-economic problems. The extraction of fossils such as shale gas can cause economic boom in the region where its production occurs. However, this phenomenon is very short-term, and the harm caused from such extraction.

Thus, shale mining can cause serious irreversible consequences, both for ecology and for humanity as a whole.

The degree of mining of shale oil and gas was the USA, where the shale boom showed stunning results. So, America managed not only to reduce the price of fuel in the domestic market, but also to become a hydrocarbon exporter, ahead of Russia on the total volume of oil and gas production.

Nevertheless, not many can boast that they know how it is mined and what shale oil is produced than it differs from "ordinary" oil and is the threat to the "classic" hydrocarbons.

Shale oil is a hydrocarbon raw material containing additional impurities in abundance. Significant volumes of such oil found in different countries, and their production is able to block the world map of energy suppliers.

The Russian Federation occupies a leading position in the volume of reserves of shale oil and gas, which are concentrated in Western Siberia (Achimov and). In second place in the volume of explored oil resources are US. The third position on the found reserves of shale oil belongs to China. At the same time, in the PRC, the volumes of shale gas deposits exceed the reserves of black gold.

Technology of mining of shale oil

Slant oil is located very deeply underground and for its production, special technologies are used, which are the most promising to develop similar deposits.

To date, shale oil can be produced in two ways:
• mine - having a variety of raw materials extraction from the well;
• open - widely used in the past. To date, has lost its popularity due to the high cost of work.

Traditional deposits contain a slight amount of hydrocarbon reserves on the planet - according to various experts 1-3%. At the same time, low-permeable shale rocks accommodate large amounts of fuel. However, the development of such deposits was not for quite a long time. The situation has changed dramatically after George Mitchell united two technologies for developing wells - horizontal drilling and french (hydraulic).

Production technology is as follows. First of all, they are trying the vertical well to the occurrence of oil-containing shale formations. Upon reaching oil shale, a horizontal stretch segment is formed by changing the drilling direction. After that, the discharge of a special liquid composition is sand in an aqueous solution of chemical reagents. The incoming substance breaks the reservoir in which oil is located, creating a lot of cracks and forming a permeable collector. The hydraulic procedure is carried out several times, increasing the amount of cracks, along which hydrocarbons in the breed are flowing into the well. Sand in the composition prevents the closure of cracks.

Disadvantages of hydraulic rupture technology:

• There is a rapid aging of the field. The average time of "life" of wells 1.5-2 years, during the first year of work debit decreases by 80%. Then prey is stopped and searched for a new well at a considerable distance from stopped developments.
• Mark carbon dioxide emissions. Nevertheless, work is underway on the creation of technologies to capture the highlighted gas. In the future, to improve the efficiency of the development of deposits, obtained carbon dioxide, plan to be processed into electricity.

It should be noted that the technology of developing shale deposits is at the stage of its formation. The cost of extraction of shale hydrocarbons exceed the cost of developing traditional oil fields. In this regard, in the near future, the repetition of shale boom should not be expected, as we observed with gas, while the detected reserves of shale black gold must be considered as the reserves of energy resources for the future.

Prey shale oil It is conducted from shale deposits that have formed millions of years ago from the remains of the ancient flora and fauna. These deposits are in a liquid or solid state. In some cases, shale rocks may differ in low insight and mined with a mining method, and after, recycled on special installations. Most often, mining of shale oil is made using drilling in the reservoir of horizontal wells, after which its numerous hydraulic plants are produced. But this method makes tremendous harm to ecology.

To date, two types of shale oil reserves are known. The first type refers to the usual having light fractions, which are located in low permeability collectors. The main method of their production is the drilling of horizontal wells and the subsequent hydraulic fracture.

With the second production method, shale oil is extracted from Kerogen, which is in the rocks of the slate. Kerogen is a substance in the process of turning into oil, but has not yet had time to become. To accelerate the transformation process, the kerogen is exposed to heat treatment, which decomposes it to the components. The process of extracting such oil is not cheap. Since it is required not only to heat the wells, but still create "freezing" around them.

Technology of mining of shale oil

Today, the technology of mining of shale oil has a very negative impact on the state of the environment. This is due to the imperfection of production technology which includes:

• Drilling vertical well at a distance of 3-4 km;
• After that, horizontal drilling is carried out;
• After that, a special solution is pumped into the cavity under the ground, which consists of chemicals, water and sand;
• After that, due to the actions of this solution, there is a large pressure and there are cracks in the ground, according to which shale oil comes on the surface.

Pollution Environment

Such technology is called - hydraulic rupture of the formation. It has a large number of negative consequences:

• For one drilled well, a huge amount of water is needed, which is enough for consumption throughout the year thousands of people.
• The solution being pumped into the well is saturated with a huge amount of harmful chemical, radioactive substances and petroleum products.
• Most of the chemical elements during evaporation form harmful carcinogens in the air.
• Heavy metals contained in an injected ground for hydraulic break solution, subsequently remain underground, which causes a huge risk of water contamination to drink.

In addition, close to the deposits of shale oil should be located not only the huge stocks of water, but also - sand and chemicals. After working out, there are huge amounts of contaminated water, which has a negative impact on the environment of the environment, as it is not subjected to disposal.

In addition, the organization conducting mining of shale oil will not disclose a list of chemical and radioactive substances used for hydraulic.

The mining of shale oil carries a large pollution of groundwater with such chemicals as benzene, toluene, ethylbenzene, arsenic, etc. Quite often, an acid-salt solution is used for hydraulic rupture, which contains polymers. For one hydraulic, approximately 300 tons of chemicals are required.

Also during the extraction of shale oil there is a large loss of methane, which significantly enhances the greenhouse effect.

Mining of shale oil in the world

It is these negative consequences that accompany the extraction on the surface of shale oil, it was the reason that many countries of Europe, for example, France, Germany, Italy and others, were forbidden to develop on their territory of shale oil to the moment until more than Perfect methods for its extraction that do not make such harms of ecology as those that are used now.

In Russia, the development of both shale oil and shale gas is not produced. Although sometimes such a question and rises. It is most actively produced by US companies, both in the United States and in other countries. For example, such Eastern European countries as Poland, Czech Republic, Ukraine, Romania, conduct active exploration of shale deposits and plans to start or have already begun extraction of shale oil and gas, despite the irreparable harm that the environment is applied.

Despite the active US production of shale oil, it is not yet able to compete with ordinary oil produced in Russia and Middle Eastern countries.

Shale gas in Russia is not yet mined, but from time to time this issue is discussed by the government. The active mining of this type of fossil goes to the United States, but so far in Europe he does not constitute competition to Russian natural gas.

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About such a concept as a shale gas, the public spoke relatively recently, however, the production of this mineral began began in the XIX century in the United States. The shale gas was particularly popular during the so-called shale revolution, which occurred in the 2000s (although the term "shale revolution" himself was introduced only in 2012). This applies to

Where the shale gas is mined

The highest figures today invariably show the United States - the state that has become a pioneer in the mining of shale gas. The desire to go in the footsteps of the United States is expressed by some countries in Europe and Asia. The controversial is the situation with Lithuania - in the EU still do not subscribe to the discussion about the rationality of such a step. Another candidate for the development of shale breed is Ukraine, as the British-Netherlands company "Shell" became interested in its eastern regions. In addition to several countries, Europe is not ready to actively produce shale fuel, due to the sharp deterioration in the environmental situation, which may follow this.

In Russia, it is recorded by deposits of shale gas, but at present the extraction is not produced, this direction is considered irrelevant in our country. As long as Russia does not produce, but if necessary, it can start developing deposits.

Other mining gas producing countries are Iran, Canada, Norway, China, the Netherlands and others, but the volumes are insignificant.

Features of prey

The feature of the mining of shale gas is that the usual drilling gives not the most effective result, because collecting a crop will be obtained only from a small area with a radius of several centimeters. The normal zone of influence should be more than a hundred meters. Therefore, for shale, the wells are needed horizontally. In this case, efficiency increases, but still not to the required level.

In order to achieve a better result, a multistage hydraulic rock is used, which is performed in several stages:

• Initially, the liquid intended for breaking the breed is fed to the most remote well zone.
• At a distance of 150-200 meters of the most distant zone, where the fluid was served, the ball is installed in the pipe. This ball serves as a valve.
• Further, everything is repeated, however, now the liquid is not supplied to the bottom of the bottom, but slightly closer to the valve. Thus, approximately 5-6 hydroprases are produced (depending on the length of the pipe). So that the breed has not closed back, is introduced into the well regulatory agent (usually sand or ceramic balls).

Seven differences of shale gas from the traditional

The differences between shale and traditional gas are as follows:

1. With from the shale, horizontal drilling is actively used, whereas in the traditional version are almost always limited exclusively vertical.
2. The hydraulic size of the rock is almost always used in mining of shale gas. With a traditional method, this is practiced extremely rarely.
3. The well, bored in shale rocks, can not be conserved, in contrast to the well normal.
4. The cost of the well for shale in two is more than the traditional (based on the temporal meter).
5. Shale gas itself is quite mid-quality. Only recycling can correct the situation.
6. The depth of the well in the slate must be several times more than with ordinary drilling.
7. If the productivity of the conventional well is almost not changed for several years and only then the performance begins to decline gradually, then the resources of the shale well are almost completely dried after the year of use.

What threat can carry gas mining from shale

The most important problem with which is faced with the extraction of shale gas is a significant negative impact on the environment.

The consequences that may arise:

• The use of a large amount of toxic substances. This applies mainly to hydraulic fluids. Hazardous substances in this case are absorbed by the soil, soils are contaminated, water. With the slightest violation of technology, poisonous substances will fall into drinking water.
• Due to the constant tensions of the soil, seismic activity increases, the occurrence of cracks, landslides, etc.
• Since the hydraulic is used not only liquid, but also gas, the harmful substances can penetrate the atmosphere and, accordingly, pollute the air. And since the air is actively moving, it can turn out very depreciation.

Environmental consequences can be catastrophic. Fearing for its ecology, Russia opposes the development of shale near its borders, in Ukraine.

Sorry in large amounts of gas affects global warming, it is formed to find it in our publication.

If you want to learn more about the global environmental problems of our time ,.

Another large-scale problem is the air ocean pollution, follow the link and read about it.

In conclusion, it can be said that although the idea to produce shale gas is rather tempting, but the technology that is used, not cheap and unsafe. Therefore, it is worth thinking well, whether it is worth it.