Scientists have recognized the fracking method as one of the most dangerous in the extraction of resources. Shale gas production: consequences and problems Oil and gas production by fracking

From the history of the development of methods for intensifying oil production

The first attempts to intensify oil production from oil wells were made as early as the 1890s. In the United States, where oil production was developing at a rapid pace at that time, a method of stimulating production from tight rocks using nitroglycerin was successfully tested. The idea was to use nitroglycerine to break up tight rocks in the bottomhole zone of the well and increase the flow of oil to the bottomhole. The method was successfully used for some time, despite its obvious danger.

Around the same time, a method was developed to stimulate oil production by treating the bottomhole zone of the well with acid. The first acid treatment, according to some sources, was carried out in 1895. The inventor of the method is credited to Herman Fresch, chief chemist at Standard Oil's Solar refinery. Fresh received a patent on acid treatment on March 17, 1896. It concerned a chemical agent (hydrochloric acid) that can react with limestone, resulting in the formation of soluble products. These products are subsequently carried out of the formation along with the well fluids.

As with all innovations, it took some time for this innovation to catch on. It took 30 years to realize the full benefits of acid treatments. The application of the method on an industrial scale began only in the 30s of the 20th century.

During these first stimulation acid treatments, it was found that pressure could fracture the formation. This is how the idea of ​​hydraulic fracturing was born, the first recorded attempt of which was made in 1947. The attempt was unsuccessful, but it inspired further research in this area.

The first commercially successful hydraulic fracturing was carried out in 1949 in the United States, after which their number began to increase dramatically. By the mid-1950s, the number of hydraulic fracturing carried out reached 3,000 per year. In 1988, the total number of hydraulic fracturing performed exceeded 1 million operations. And that's just in the US.

In domestic practice, the hydraulic fracturing method has been used since 1952. The peak of the application of the method was reached in 1959, after which the number of operations decreased, and then completely stopped. From the beginning of the 1970s to the end of the 1980s, hydraulic fracturing in domestic oil production on an industrial scale was not carried out. In connection with the commissioning of large oil fields in Western Siberia, the need for intensification of production simply disappeared. The revival of the practice of hydraulic fracturing in Russia began only in the late 1980s.

Currently, the leading positions in the number of hydraulic fracturing are occupied by the United States and Canada. They are followed by Russia, where the use of hydraulic fracturing technology is carried out mainly in the oil fields of Western Siberia. Russia is practically the only country (apart from Argentina) outside the US and Canada where hydraulic fracturing is a common practice and is perceived quite adequately. In other countries, the application of hydraulic fracturing technology is difficult due to local bias and misunderstanding of the technology. In some countries, there are significant restrictions on the use of hydraulic fracturing technology, up to a direct ban on its use.

What is a GRP?

The essence of the hydraulic fracturing method lies in the injection of high-pressure fluid into the bottomhole zone, as a result of which the rock breaks and the formation of new or expansion of existing cracks occurs. To keep the cracks open when the pressure is reduced, a fixing agent - proppant - is pumped into them together with the liquid. The fluid that transmits pressure to the formation rock is called the fracturing fluid.

rupture crack, formed as a result of hydraulic fracturing, can be horizontal or vertical. Rock rupture occurs in the direction perpendicular to the least stress. As a rule, horizontal fractures appear as a result of hydraulic fracturing to a depth of about 500 meters. At a depth below 500 meters, vertical cracks appear. Since productive oil-saturated formations occur, as a rule, at a depth of less than 500 meters, fractures in oil wells are always vertical.

Types of hydraulic fracturing

Distinguish proppant hydraulic fracturing And acid fracturing.

Proppant hydraulic fracturing- hydraulic fracturing using proppant - a proppant that is pumped during hydraulic fracturing to prevent the created fracture from closing. This type of hydraulic fracturing is used, as a rule, in terrigenous formations.

When people talk about hydraulic fracturing, they most often mean proppant hydraulic fracturing.

Acid fracturing– hydraulic fracturing, in which acid is used as the fracturing fluid. It is used in the case of carbonate formations. The network of cracks and vugs created with the help of acid and high pressure does not require proppant fixing. It differs from conventional acid treatment by a much larger volume of acid used and injection pressure (above the fracture pressure of the rock).

The main factors on which the success of hydraulic fracturing depends:

  • the right choice of object for operations;
  • use of hydraulic fracturing technology that is optimal for given conditions;
  • competent selection of wells for processing.

Environmental safety of hydraulic fracturing

The large-scale use of hydraulic fracturing for a long period of time (more than 50 years) confirms the environmental safety of the method. Work on hydraulic fracturing is carried out under the control of state regulatory bodies and supervisors of the oil companies themselves. Since the oil reservoirs lie at great depths (1000-3000 m), the influence of the process on surface and ground waters is excluded. Itself, using several columns, is designed to ensure the environmental safety of the oil production process and work carried out in wells.

Finally

Hydraulic fracturing technology has come a long way - from single operations to the most powerful tool for increasing well productivity and reservoir management. Currently, many oil fields owe their development to hydraulic fracturing methods. For example, in the USA, where hydraulic fracturing technology is used extremely widely, approximately 25-30% of all reserves have become commercially available thanks to this technology. According to experts, hydraulic fracturing contributed to an increase in recoverable oil reserves in North America by 8 billion barrels.

Along with the formation of fractures in the reservoir to increase well productivity, hydraulic fracturing can also be used to overcome the contamination of the bottomhole zone of the reservoir, as a means of improving the efficiency of operations in the implementation of secondary methods of oil production, and to increase the injectivity of wells when burying salt solutions and industrial waste in underground reservoirs. .

Hydraulic fracturing (HF or fracturing, from English hydraulic fracturing) is an integral process of well stimulation in the process of oil and gas production from shale rocks.
Not so long ago, there was a lot of talk about hydraulic fracturing and a lot of organizations were against permitting hydraulic fracturing. The main argument against hydraulic fracturing was the theory that hydraulic fracturing pollutes underground sources of fresh water very much, to the point that water with gas impurities begins to flow from the tap, which can be ignited, which, by the way, was filmed in a video that got hit in many broadcasts and news releases.

Today I will touch on the issue of hydraulic fracturing and we will look at how everything looks in practice. And then I will talk about how true the talk about the pollution of fresh sources and the harmful effects of hydraulic fracturing is. I will also touch on a sensational video about how people set fire to water in a tap. Everyone saw the video, but almost no one knows the story behind the scenes of this video.

1. First, let's look at what hydraulic fracturing is in general, because. many do not know this. Traditionally, oil and gas have been extracted from sandy rocks, which have a high porosity. Oil in such rocks can freely migrate among the grains of sand to the well. Shale rocks, on the other hand, have very low porosity and contain oil in fractures within the shale formation. The task of hydraulic fracturing is to enlarge these fractures (or form new ones), giving oil a freer path to the well. To do this, a special solution (looks like jelly) is injected into the oil-saturated shale formation under high pressure, consisting of sand, water and additional chemical additives. Under the high pressure of the injected fluid, shale forms new cracks and expands existing ones, and sand (proppant) does not allow cracks to close, thus improving rock permeability. There are two types of hydraulic fracturing - proppant (using sand), and acid. The type of hydraulic fracturing is selected based on the geology of the formation being fractured.

2. Hydraulic fracturing requires a fairly large amount of equipment and personnel. Technically, the process is identical regardless of the company conducting the work. A trailer with a block of manifolds is connected to the well fittings. This trailer is connected to pumping units that inject hydraulic fracturing solution into the well. A mixing plant is installed behind the pumping stations, near which a trailer with sand and water is installed. A monitoring station is being installed behind all this economy. A crane and a logging machine are installed on the opposite side of the armature.
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On the right, in the photo - a block of manifolds, on the left - pump trailers, then - fittings and behind it a crane. The logging machine is on the left, behind the trailers. You can see it in other photos.

3. The hydraulic fracturing process begins in the mixer, where sand and water are supplied, as well as chemical additives. All this is mixed to a certain consistency, after which it is fed to pumping units. At the outlet of the pumping unit, the hydraulic fracturing solution enters the manifold block (this is something like a common mixer for all pumping units), after which the solution is sent to the well. The hydraulic fracturing process is not carried out in one approach, but goes through stages. Stages are compiled by a team of petrophysicists based on acoustic logging, usually an open hole, taken while drilling. During each stage, the logging team puts a plug in the well, separating the hydraulic fracturing interval from the rest of the well, after which it perforates the interval. Then the hydraulic fracturing of the interval passes, and the plug is removed. At the new interval, a new plug is placed, perforation takes place again, and a new hydraulic fracturing interval. The hydraulic fracturing process can last from several days to several weeks, and the number of intervals can reach hundreds.
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This is what the mixer looks like. The hoses going to it are water connection lines.

4. Pumps used in hydraulic fracturing are equipped with diesel engines with power from 1,000 to 2,500 hp. Powerful pump trailers are capable of pumping pressure up to 80 MPa, with bandwidth 5-6 barrels per minute. The number of pumps is calculated by the same petrophysicists based on logging. The required pressure for fracturing is calculated, and based on this, the number of pumping stations is calculated. During operation, the number of pumps used always exceeds the calculated number. Each pump runs at a slower pace than required. This is done for two reasons. Firstly, this significantly saves the life of the pumps, and secondly, if one of the pumps fails, it is simply removed from the line, and the pressure on the remaining pumps slightly increases. Thus, a pump failure does not affect the hydraulic fracturing process. This is very important, because if the process has already started, then stopping is unacceptable.
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Pumps connected to the manifold block. The "booth" in the background is the control point for the operation of the mixer. The opposite view, from the booth, is in the second photo.

5. Current fracturing technology was not born yesterday. The first attempts at hydraulic fracturing were made as early as 1900. A charge of nitroglycerin descended into the well, after which it detonated. At the same time, acid stimulation of wells was tested. But both methods, despite their early birth, still required a very long time to become perfect. Hydraulic fracturing boomed only in the 1950s, with the development of proppant. Today, the method continues to evolve and improve. When a well is stimulated, its life is extended and the flow rate increases. On average, the increase in oil flow to the estimated well flow rate is up to 10,000 tons per year. By the way, hydraulic fracturing is also carried out in vertical wells in sandstone, so it is a mistake to think that the process is acceptable only in shale rocks and has just been born. Today, about half of the wells are undergoing hydraulic fracturing stimulation.

6. However, with the development horizontal drilling very many people began to speak out against well stimulation, because. Hydraulic fracturing harms the environment. A lot of works were written, videos were shot and investigations were carried out. If you read all these articles, then everything is smooth, but this is only at first glance, but we will take a closer look at the details.
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View of the manifold block from the fittings. By the way, walking among trailers and pipes is possible only during logging, when there is no pressure in the injection system. Any person who appears among the trailers with pumps or pipes during the hydraulic fracturing is fired on the spot without talking. Safety first.

7. The main argument against hydraulic fracturing is the contamination of groundwater with chemicals. What exactly is included in the composition of the solution is a secret of the companies, but some elements are nevertheless disclosed and are in open public sources. It is enough to refer to the "FrakFocus" hydraulic fracturing database, and you can find the general composition of the gel (1, 2). 99% of the gel consists of water, only the remaining percentage is chemical additives. The proppant itself is not included in the calculation in this case, because It is not a liquid and is harmless. So, what is included in the remaining percentage? And it includes - acid, anti-corrosion element, friction mixture, glue and additives for gel viscosity. For each well, the elements from the list are selected individually, in total there can be from 3 to 12 falling into one of the above categories. Indeed, all these elements are toxic and not acceptable to humans. Examples of specific additives are, for example: Ammonium persulfate, Hydrochloric acid, Muriatic acid, Ethylene glycol.
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Logging machine. The team collects charges and prepares a plug for perforation.

8. How can these chemicals get to the top without being trapped in the oil? We find the answer in the report of the Association for the Protection of the Environment (3). This can happen either due to explosions at the wells, or due to spills during hydraulic fracturing, or due to spills of utilization pools, or due to problems with the integrity of the wells. The first three reasons are not able to infect water sources over vast areas, only the last option remains, which is now officially confirmed by the US Academy of Sciences (4).

9. For those who are interested in how the movement of fluids inside rocks is monitored, this is done using the so-called tracers. A special fluid with a certain radiation background is injected into the well. After that, in neighboring wells, and on the surface, they put sensors that respond to radiation. In this way, it is possible to simulate very accurately the "communication" of wells with each other, as well as to detect leaks inside the casing strings of wells. Do not worry, the background of such liquids is very weak, and the radioactive elements used in such studies decompose very quickly without leaving traces.

10. Oil rises to the surface not in its pure form, but with impurities of water, dirt and various chemical elements, including chemical additives used during hydraulic fracturing. Passing through separators, oil is separated from impurities, and impurities are disposed of through special disposal wells. In simple terms, the waste is pumped back into the ground. The casing pipe is cemented, but it rusts over time, and at some point it starts to leak. If the pipe has good cement in the annulus, then this rust does not matter, there will be no leakage from the pipe, but if there is no cement, or the cement work was done poorly, then the fluids from the well will enter the annulus, from where they can get anywhere, t .to. the leak may be above the oil traps. This problem has been known to engineers for a very long time, and the focus on this problem was sharpened back in the early 2000s, i.e. long before the accusations against the PIU. Back then, when many companies created separate departments within themselves responsible for the integrity of wells and their verification. Leaks can bring with them a lot of dirt, gas (not only natural, but also hydrogen sulfide), heavy metals into the upper layers of rocks and can contaminate clean water sources even without hydraulic fracturing chemicals. Therefore, the alarm raised today is very strange, the problem existed without hydraulic fracturing. This is especially true for old wells that are over 50 years old.

11. Today, regulations in many states are changing at an astonishing rate, especially in Texas, New Mexico, Pennsylvania, and North Dakota. But to the surprise of many - not at all because of hydraulic fracturing, but because of the explosion of the BP platform in the Gulf of Mexico. In many cases, companies hastily conduct logs to check the integrity of the casing and cement behind it, and transmit this data to government commissions. By the way, so far no one officially requires well integrity logging, but companies spend money on their own and make this work. In case of unsatisfactory condition, the wells are killed. To give credit to the engineers, for example, out of 20,000 wells inspected in Pennsylvania in 2008, only 243 cases of leakage into the upper water layers were recorded (5). In other words, hydraulic fracturing has nothing to do with the contamination and gasification of fresh water, the fault is the poor integrity of wells that were not plugged in time. And there are plenty of toxic elements in oil-saturated reservoirs and without chemical additives used during hydraulic fracturing.

12. Another argument that the opponents of hydraulic fracturing bring is the monstrous amount of fresh water required for the operation. A lot of water is required for hydraulic fracturing. A report by the Environmental Protection Association gives figures that a total of 946 billion liters of water were used from 2005 to 2013, while 82,000 hydraulic fracturing operations were carried out during this time (6). The figure is interesting, if you do not think about it. As I mentioned before, hydraulic fracturing has been widely used since the 50s, but the statistics only begin in 2005, when massive horizontal drilling began. Why? It would be good to mention the total number of hydraulic fracturing operations and the amount of water used up to 2005. The answer to this question, in part, can be found in the same FracFocus hydraulic fracturing database - since 1949, more than 1 million hydraulic fracturing operations have been carried out (7). So how much water was used during this time? For some reason the report doesn't mention this. Probably because 82 thousand operations somehow fade against the backdrop of a million.

13. There are also many questions for the EPA (Environmental Protection Agency). A lot of people like to refer to the EPA as a very good source. The source is indeed weighty, but a weighty source can give misinformation. At one time, the EPA made a splash all over the world, the problem is that having made a fuss, few people know how it all ended, and the story ended very badly, for some.
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This is what the proppant looks like. It is called sand, in fact it is not the sand that is mined in quarries and in which children play. Today, proppant is manufactured at special factories, and it happens different types. Usually the identification is in proportion to the grains of sand, for example, this is a 16/20 proppant. In a separate post directly about the hydraulic fracturing process, I will dwell on the types of proppant and show its various types. And it is called sand because the Halliburton company used ordinary fine river sand during the first hydraulic fracturing.

14. The EPA has two very important interesting stories(8). So, the first story.
In the suburbs of Dallas, in the city of Fort Worth, an oil company was drilling wells for gas production, naturally using hydraulic fracturing. In 2010, EPA Regional Director, Dr. Al Armendariz filed an emergency lawsuit against the company. The lawsuit stated that people living near the company's wells were in danger, because. the company's wells gasify nearby water wells. At that moment, the tensions around the fracturing were very high, and the patience of the Texas Railway Commission exploded. For those who have forgotten, in Texas, land use and drilling is handled by the Railroad Commission. A scientific group was formed and sent to investigate the quality of the water. The upper methane near Fort Worth is at a depth of 120 meters and has no cap, while the depth of water wells did not exceed 35 meters, and the hydraulic fracturing taking place on the company's wells was carried out at a depth of 1,500 meters. So, it turned out that no tests were carried out to study the harmful effects of the EPA, but they simply took it and said that hydraulic fracturing pollutes fresh water, and sued. And the commission took and conducted tests. After checking the integrity of the wells, taking soil samples and carrying out the necessary tests, the commission issued a single verdict - not a single well has leaks and has nothing to do with gasification of fresh water. The EPA lost two court cases, the company and the second court case directly to the Railway Commission, after which the director of the EPA, Dr. Al Armendariz, resigned "for own will". Now he works in a nightclub in the capital of Texas, the city of Austin.

By the way, there is indeed a problem of water gasification, but it is in no way connected with hydraulic fracturing, but is connected with a very shallow occurrence of methane. Gas from the upper layers gradually rises to the top and enters the water wells. This is a natural process that has nothing to do with mining and drilling. Such gasification affects not only water wells, but also lakes and springs.
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On the right is the mixer bucket. On the left is a proppant container. The proppant is fed into the bucket on a conveyor belt, after which the mixer takes it to a centrifuge, where it is mixed with water and chemical additives. After that, the gel is fed to the pumps.

15. And now, dear readers, sit back, stock up on popcorn and fasten your seat belts - I will talk about the sensational video in which people set fire to water flowing from the tap.

Immediately after the story with the negligent doctor from the EPA, the railway commission turned its eyes to a very popular video, which by that time had not been shown anywhere. One Steven Lipsky, a freshwater well owner, and environmental consultant Alice Rich filmed a video in which they set fire to tap water. Water intake was from Stephen's water wells. The water caught fire, allegedly due to the high concentration of gas, which is the fault of the oil company with its ill-fated hydraulic fracturing. In fact, during the investigation, both defendants admitted that a propane tank was connected to the pipeline system, and this was done in order to attract news outlets, which would lead people to believe that the hydraulic fracturing was to blame for the gasification of fresh water. In this case, it was proven that Alice Rich knew about the falsification, but wanted to pass knowingly false data to the EPA and there was a conspiracy between Alice and Stephen to slander the activities of the company. Again, it has been proven that the company and the fracturing process does not harm the environment. After this incident, by the way, everyone was somewhat embarrassed about the accusations of hydraulic fracturing in gasification of water. Apparently no one is in a hurry to go to jail. Or did everyone understand at once that this process is natural and existed before the advent of hydraulic fracturing?

So, summing up all of the above - any human activity harms the environment, oil production is no exception. Hydraulic fracturing, by itself, does not harm the environment, and has existed on a large scale in the industry for more than 60 years. Chemical additives injected during hydraulic fracturing to great depths do not pose any threat to the upper water layers. The real issue today is cementing and maintaining well integrity, which companies are working hard on. And there are enough chemical elements and dirt that can poison fresh water in oil-saturated reservoirs even without hydraulic fracturing. The gasification process itself is natural, and such a problem was known even without hydraulic fracturing, and this problem was also fought before hydraulic fracturing.

Today, the oil industry is much cleaner and greener than ever in history, and continues to fight for the environment, and many of the stories and tales come from very unscrupulous officials in government departments. Unfortunately, such stories very quickly remain in the memory of most people, and are very slowly refuted by facts that are of little interest to anyone.
It must also be remembered that the war oil companies was, is and will always be, and cheap gas in huge volumes not all to the yard.

Important addition:
Due to the fact that references to Pennsylvania and the presence of gas in fresh water wells began to appear in the comments, I decided to also clarify this issue. Pennsylvania is very rich in gas, and one of the most powerful booms in horizontal gas drilling occurred in this state, especially in its northern part. The problem is that there are several gas deposits (methane and ethane) in the state. Top gas reservoirs are called Devonian while deep shale gas reservoirs are called Marcellus. After a detailed molecular analysis of the gas composition and testing of 1,701 water wells (from 2008 to 2011) in the upstate, a single verdict was given - there is no shale gas in the water wells, but methane and ethane from the Devonian upper layer are present. Gasification of wells is natural and associated with geological processes, identical to the problem of Texas. The hydraulic fracturing process does not contribute to the migration of shale gas to the surface.

In addition, in Pennsylvania, due to the fact that it was one of the first states in the USA at all, there are very, very many documents that go back to the early 1800s, which mention burning streams, as well as flammable sources of water, with an abundant concentration of gas in it. There are a lot of documents that mention the presence of a very high concentration of methane at a depth of 20, only 20 meters! The mass of documents indicates a very high concentration of methane in rivers and streams, more than 10 mg/L. Therefore, unlike Texas, where I personally did not hear anything about such documents, in Pennsylvania the problem of gasification was documented even before the start of any drilling at all. Therefore, what is the danger of hydraulic fracturing if there are documents that are more than 200 years old, and it is also molecularly proven that the gas in water wells is not shale? Organizations struggling with hydraulic fracturing for some reason forget about such documents, or they are not engaged in such studies and are not interested.

Also noteworthy is that Pennsylvania is one of the states that requires operators to analyze Act 13 fresh water quality prior to drilling to monitor possible contamination levels. So, when analyzing water quality, almost always the allowable concentration of dissolved gas, 7000 μg/L, is exceeded. The question is why then people did not complain about the state of health, ecology and ruined land for two hundred years, and suddenly they suddenly realized to complain en masse with the start of gas drilling? (nine).
Gasification is natural, and is not a consequence of hydraulic fracturing and drilling in general, this problem exists in any country with gas deposits on the surface.

P.S:
I think a lot of people will be interested to know about hydraulic fracturing in Russia. Today, about a hundred hydraulic fracturing complexes operate in Russia. All complexes are of foreign assembly. Russia has been showing interest in hydraulic fracturing since the post-war period, but due to the huge gas reserves, in principle, hydraulic fracturing does not have a rapid development today. Although work and tests are being carried out.

The "shale revolution" is obviously taking over the minds of politicians and businessmen all over the world. The Americans hold the palm in this area, but, apparently, there is a possibility that the rest of the world will soon join them. Of course, there are states where there is practically no shale gas production - in Russia, for example, the main percentage of political and business elites are rather skeptical about this undertaking. At the same time, the matter is not so much in the factor of economic profitability. The most important circumstance that can affect the prospects of such an industry as shale gas production is the consequences for the environment. Today we will study this aspect.

What is shale gas?

But first, a little theoretical digression. What is a shale mineral that is extracted from a special type of minerals - The main method by which shale gas is extracted, the consequences of which we will study today, guided by the positions of experts, is fracking, or hydraulic fracturing. It's set up like this. A pipe is inserted into the bowels of the earth in an almost horizontal position, and one of its branches is brought to the surface.

In the process of fracking, pressure is built up in the gas storage, which causes shale gas to escape to the top, where it is collected. The extraction of the mentioned mineral has gained the greatest popularity in North America. According to some experts, the industry's revenue growth in the US market over the past few years has amounted to several hundred percent. However, unconditional economic success in terms of developing new methods of producing "blue fuel" may be accompanied by huge problems associated with the extraction of shale gas. They are, as we have already said, ecological in nature.

Harm to the environment

What the US and other energy powers should look to, experts say Special attention, working in such an area as shale gas production, - the consequences for the environment. The most important threat to the environment is fraught with the main method of extracting minerals from the bowels of the earth. We are talking about the same fracking. It, as we have already said, is a supply of water into the earth's layer (under very high pressure). Such an impact can have a pronounced Negative influence on the environment.

Reagents in action

Technological features of fracking are not the only character. Current methods of extracting shale gas involve the use of several hundred varieties of reactive, and potentially toxic, substances. What does this mean? The fact is that the development of the corresponding deposits requires the use of large volumes of fresh water. Its density, as a rule, is less than that characteristic of groundwater. And therefore, light layers of liquid, one way or another, can eventually rise to the surface and reach the mixing zone with drinking sources. However, they are likely to contain toxic impurities.

Moreover, it is possible that light water will return to the surface contaminated not with chemical, but with completely natural, but still harmful to human health and the environment, substances that may be contained in the depths of the earth's interior. An indicative moment: it is known that it is planned to produce shale gas in Ukraine, in the Carpathian region. However, experts from one of the scientific centers conducted a study, during which it turned out that the layers of the earth in those regions that are supposed to contain shale gas are characterized by an increased content of metals - nickel, barium, uranium.

Technology miscalculation

By the way, a number of experts from Ukraine urge to pay attention not so much to the problems of shale gas production in terms of the use of harmful substances, but to the shortcomings in the technologies used by gas companies. Representatives of the scientific community of Ukraine in one of their reports on environmental issues put forward the relevant theses. What is their essence? The conclusions of scientists, in general, boil down to the fact that shale gas production in Ukraine can cause significant damage to soil fertility. The fact is that with those technologies that are used to isolate harmful substances, some materials will be located under arable soil. Accordingly, it will be problematic to grow something above them, in the upper layers of the soil.

Ukrainian bowels

There are also concerns among Ukrainian experts about the possible consumption of reserves drinking water, which can be a strategically significant resource. At the same time, already in 2010, when the shale revolution was just gaining momentum, the Ukrainian authorities issued licenses for shale gas exploration to companies like ExxonMobil and Shell. In 2012, exploration wells were drilled in the Kharkiv region.

This could indicate, experts believe, the interest of the Ukrainian authorities in the development of "shale" prospects, probably in order to reduce dependence on the supply of blue fuel from the Russian Federation. But now it is not known, analysts say, what are the future prospects for work in this direction (due to well-known political events).

Problem fracking

Continuing the discussion about the shortcomings of shale gas production technologies, one can also pay attention to other noteworthy theses. In particular, some substances can be used in fracking. They are used as fracturing fluids. At the same time, their frequent use can lead to a significant deterioration in the degree of rock permeability for water flows. In order to avoid this, gas workers can use water that uses soluble chemical derivatives of substances similar in composition to cellulose. And they pose a serious threat to human health.

Salts and radiation

There were precedents when the presence of chemicals in the waters in the area of ​​shale wells was recorded by scientists not only in the calculated aspect, but also in practice. After analyzing the water flowing into the sewage treatment plant in Pennsylvania, the experts found a much higher than normal level of salts - chlorides, bromides. Some of the substances found in water can react with atmospheric gases such as ozone, resulting in the formation of toxic products. Also, in some layers of the subsoil located in areas where shale gas is produced, the Americans discovered radium. Which is, therefore, radioactive. In addition to salts and radium, in the waters that are concentrated in areas where the main method of extracting shale gas (fracking) is used, scientists have discovered various kinds of benzenes and toluene.

legal loophole

Some lawyers point out that the environmental damage caused by American shale gas companies is almost legal in nature. The fact is that in 2005, a legal act was adopted in the United States, according to which the fracking method, or hydraulic fracturing, was withdrawn from the monitoring of the Environmental Protection Agency. This department, in particular, ensured that American businessmen acted in accordance with the provisions of the Drinking Water Protection Act.

However, with the adoption of a new legal act, US enterprises were able to operate outside the Agency's control zone. It has become possible, experts say, to extract shale oil and gas in close proximity to underground sources of drinking water. And this is despite the fact that the Agency, in one of its studies, concluded that the sources continue to become contaminated, and not so much during the fracking process, but some time after the work is completed. Analysts believe that the law was passed not without political pressure.

Freedom in Europe

A number of experts emphasize that not only the Americans, but also the Europeans do not want to understand the dangers of shale gas production in the potential. In particular, the European Commission, which develops sources of law in various areas of the EU economy, did not even begin to create a separate law regulating environmental issues in this industry. The agency limited itself, analysts emphasize, to just issuing a recommendation that does not actually bind energy companies to anything.

At the same time, according to experts, the Europeans are not yet too keen on the earliest possible start of work on the extraction of blue fuel in practice. It is possible that all those discussions in the EU that are connected with the "shale" topic are just political speculations. And in fact, the Europeans, in principle, are not going to develop gas production by unconventional methods. At least in the near future.

Complaints without satisfaction

There is evidence that in those areas of the United States where shale gas is being produced, the consequences of an environmental nature have already made themselves felt - and not only at the level of industrial research, but also among ordinary citizens. Americans living next to wells where fracking is used began to notice that tap water had lost a lot of quality. They are trying to protest against shale gas production in their area. However, their capabilities, according to experts, are not comparable with the resources of energy corporations. The business scheme is quite simple. When there are claims from citizens, they form by hiring environmentalists. In accordance with these documents, drinking water must be in perfect order. If the residents are not satisfied with these papers, then, as reported by a number of sources, the gas workers pay them pre-trial compensation in exchange for signing non-disclosure agreements on such transactions. As a result, the citizen loses the right to report something to the press.

The verdict will not burden

If, however, litigation is nevertheless initiated, then decisions made not in favor of energy companies, in fact, are not very burdensome for gas companies. In particular, according to some of them, corporations undertake to supply citizens with drinking water from environmentally friendly sources at their own expense or install treatment equipment for them. But if in the first case the affected residents, in principle, can be satisfied, then in the second - as experts believe - there may not be much reason for optimism, since some can still seep through the filters.

The authorities decide

There is an opinion among experts that interest in shale in the US, as well as in many other countries of the world, is largely political. This, in particular, may be evidenced by the fact that many gas corporations are supported by the government - especially in such an aspect as tax incentives. Experts assess the economic viability of the "shale revolution" ambiguously.

Drinking water factor

Above, we talked about the fact that Ukrainian experts question the prospects for shale gas production in their country, largely due to the fact that fracking technology may require spending large amounts of drinking water. I must say that similar concerns are expressed by experts from other states. The fact is that even without shale gas, it is already being observed in many regions of the planet. And it is likely that a similar situation may soon be observed in developed countries. And the "shale revolution", of course, will only help accelerate this process.

Ambiguous slate

There is an opinion that shale gas production in Russia and other countries is not developed at all, or at least not at the same pace as in America, just because of the factors we have considered. These are, first of all, the risks of environmental pollution with toxic, and sometimes radioactive, compounds that occur during fracking. There is also the possibility of depletion of drinking water reserves, which may soon become a resource that is not inferior to blue fuel in terms of importance even in developed countries. Of course, the economic component is also taken into account - there is no consensus among scientists on the profitability of shale deposits.

This technology, which has been used to intensify the work and increase the productivity of oil wells for more than half a century, is perhaps the most heated debate among environmentalists, scientists, ordinary citizens, and often even workers in the extractive industry themselves. Meanwhile, the mixture that is pumped into the well during hydraulic fracturing is 99% water and sand, and only 1% chemical reagents.

What hinders oil recovery

The main reason for the low productivity of wells, along with poor natural permeability of the formation and low-quality perforation, is a decrease in the permeability of the bottomhole formation zone. This is the name of the reservoir area around the wellbore, which is subject to the most intense impact of various processes that accompany the construction of the well and its subsequent operation and violate the initial equilibrium mechanical and physico-chemical state of the reservoir. The drilling itself introduces changes in the distribution of internal stresses in the surrounding rock. A decrease in well productivity during drilling also occurs as a result of the penetration of the drilling fluid or its filtrate into the bottomhole formation zone.

The reason for the low productivity of wells can also be poor-quality perforation due to the use of low-power perforators, especially in deep wells, where the energy of the explosion of charges is absorbed by the energy of high hydrostatic pressures.

A decrease in the permeability of the bottomhole formation zone also occurs during well operation, which is accompanied by a violation of the thermobaric equilibrium in the reservoir system and the release of free gas, paraffin and asphalt-resinous substances from the oil, which clog the pore space of the reservoir. Intensive contamination of the bottom-hole formation zone is also noted as a result of the penetration of working fluids into it during various well drilling operations. repair work. The injectivity of injection wells deteriorates due to blockage of the pore space of the formation by corrosion products, silt, oil products contained in the injected water. As a result of such processes, liquid and gas filtration resistances increase, well flow rates decrease, and there is a need for artificial stimulation of the bottomhole formation zone in order to increase well productivity and improve their hydrodynamic connection with the formation.

Technologyfracking

To increase oil recovery, intensify the operation of oil and gas wells and increase the injectivity of injection wells, the method of hydraulic fracturing or fracking is used. The technology consists in creating a highly conductive fracture in the target formation under the action of a fluid injected into it under pressure to ensure the flow of the produced fluid to the bottom of the well. After hydraulic fracturing, the well flow rate, as a rule, increases sharply - or the drawdown decreases significantly. Hydraulic fracturing technology makes it possible to "revive" idle wells, where oil or gas production by traditional methods is no longer possible or unprofitable.

Hydraulic fracturing (HF) is one of the most effective means of increasing well productivity, since it not only leads to the intensification of the development of reserves located in the well drainage zone, but also, under certain conditions, allows to significantly expand this zone by adding poorly drained zones to the development and interlayers - and, consequently, to achieve a higher ultimate oil recovery.

Historyhydraulic fracturing method

The first attempts to intensify oil production from oil wells were made as early as the 1890s. In the United States, where oil production was developing at a rapid pace at that time, a method of stimulating production from tight rocks using nitroglycerin was successfully tested. The idea was to use an explosion of nitroglycerin to break up dense rocks in the bottomhole zone of the well and increase the flow of oil to the bottomhole. The method was successfully used for some time, despite its obvious danger.

The first commercially successful hydraulic fracturing was carried out in 1949 in the United States, after which their number began to increase dramatically. By the mid-1950s, the number of hydraulic fracturing carried out reached 3,000 per year. In 1988, the total number of hydraulic fracturing performed exceeded 1 million operations, and this is only in the USA.

In domestic practice, the hydraulic fracturing method has been used since 1952. The peak of the application of the method was reached in 1959, after which the number of operations decreased, and then this practice stopped altogether. From the beginning of the 1970s to the end of the 1980s, hydraulic fracturing in domestic oil production on an industrial scale was not carried out. In connection with the commissioning of large oil fields in Western Siberia, the need for intensification of production simply disappeared.

… And today's day

The revival of the practice of hydraulic fracturing in Russia began only in the late 1980s. Currently, the leading positions in the number of hydraulic fracturing are occupied by the United States and Canada. They are followed by Russia, where the use of hydraulic fracturing technology is carried out mainly in the oil fields of Western Siberia. Russia is practically the only country (apart from Argentina) outside the US and Canada where hydraulic fracturing is a common practice and is perceived quite adequately. In other countries, the application of hydraulic fracturing technology is difficult due to local bias and misunderstanding of the technology. Some of them have significant restrictions on the use of hydraulic fracturing technology, up to a direct ban on its use.

A number of experts argue that the use of hydraulic fracturing technology in oil production is an irrational, barbaric approach to the ecosystem. At the same time, the method is widely used by almost all major oil companies.

The application of hydraulic fracturing technology is quite extensive - from low to high permeability reservoirs in gas, gas condensate and oil wells. In addition, with the use of hydraulic fracturing, it is possible to solve specific problems, for example, to eliminate sand in the wells, to obtain information about the reservoir properties of test objects in exploration wells, etc.

In recent years, the development of hydraulic fracturing technologies in Russia is aimed at increasing the volume of proppant injection, the production of nitrogen fracturing, as well as multi-stage hydraulic fracturing in the reservoir.

Equipment forhydraulic fracturing

The equipment required for hydraulic fracturing is produced by a number of enterprises, both foreign and domestic. One of them is the TRUST-ENGINEERING company, which represents wide choose hydraulic fracturing equipment in the standard version, and in the form of a modification performed at the request of the customer .

As a competitive advantage of the products of TRUST-ENGINEERING LLC, it is necessary to note the high share of localization of production; application of the most modern design and production technologies; the use of components and components from world leaders in the industry. It is important to note the high culture of design, production, warranty, post-warranty and after-sales service. Equipment for hydraulic fracturing manufactured by TRUST-ENGINEERING LLC is easier to purchase due to the presence of representative offices in Moscow ( the Russian Federation), Tashkent (Republic of Uzbekistan), Atyrau (Republic of Kazakhstan), as well as in Pancevo (Serbia).

Of course, the hydraulic fracturing method, like any other technology used in the extractive industry, is not without certain drawbacks. One of the disadvantages of fracking is that the positive effect of the operation can be negated by unforeseen situations, the risk of which is quite high with such an extensive intervention (for example, an unforeseen violation of the tightness of a nearby water reservoir is possible). At the same time. Hydraulic fracturing is one of the most effective methods of well stimulation today, opening not only low-permeability reservoirs, but also reservoirs of medium and high permeability. The greatest effect from hydraulic fracturing can be achieved with the introduction of an integrated approach to the design of hydraulic fracturing as an element of the development system, taking into account various factors, such as reservoir conductivity, well spacing system, reservoir energy potential, fracture mechanics, fracturing fluid and proppant characteristics, technological and economic limitations. .

Today, shale gas extraction by hydraulic fracturing, or fracking for short, is on the list of technologies that are popularly unloved. Fracking is a method of pumping water under high pressure to extract natural gas from the broken layer. Hydraulic fracturing is widely criticized in the world as a dangerous method, which is even banned in a number of countries. Hydraulic fracturing is accused of using toxic components that pollute the environment and causing earthquakes. Opponents of the method argue that the result of hydraulic fracturing will be the contamination of drinking water with methane to an explosive state. And pollution with toxins will cause unknown diseases. Sounds intimidating? Still would!

Hydraulic fracturing is an excellent target to look at with a skeptical eye.

In 2010, the film Gasland threw accusatory statements to the public about more than just fracking. The film painted an eerie picture of secrecy, the lust for profit at any cost, and the thoughtless pollution of all living things around by companies mining underground resources. The mining companies responded with the Debunking Gasland web page and other publications that not only denied the allegations, but attacked the film's producer as an activist in the movement. As was said in response to the film, the applications are thrown without geological expertise and experience in drilling wells. Which of the warring parties should believe a common person from the street? Unfortunately, one has to listen to either the opponents of hydraulic fracturing or the supporters. Rarely or never has the man on the street dispassionately analyzed the pros and cons of fracking based on scientifically proven facts.

Natural gas is found in shale or coal seams and leaves these natural reservoirs through natural faults. Deposits close to the surface are relatively easy to extract by drilling without fracking. But deeper and richer deposits are found at depths of 1.5-6 kilometers, where under higher pressure the formations have significantly fewer faults and the permeability of the rock is insufficient to extract large amounts of shale gas. In these deep, dense rocks, it makes sense to apply the method of extracting shale gas by hydraulic fracturing. The shale formation is usually no thicker than a hundred meters, so wells are drilled horizontally to a depth of about one kilometer and a pipe is installed, getting the opportunity to create a hydraulic lever. By pumping water into a small hole in a pipe, it is possible to create pressure up to 700 atmospheres and act on a vast area. The pressure breaks the formation into many cracks of about 1 mm, allowing shale gas to leave its place. Hydraulic fracturing involves pumping water containing sand, and this is the essence of the whole method. Sand particles fall into microcracks, expanding them to the point where gas can escape. Further, extraction wells are arranged, and the production process becomes much more productive, since the gas now has enough ways to leave deep layers.

Although hydraulic fracturing has been used since the early 1950s, widespread shale gas production developed in the 2000s. About 90% of wells in the US work due to hydraulic fracturing. Fracking brings economic and political benefits to the country, as a result of an increase in energy production.

So, what problems arise due to the application of the hydraulic fracturing method? The most dramatic and popularized effect was drinking water saturated with methane, the main component of natural gas. Saturated, as opponents assure, so much so that it is set on fire with a match. Burning water does occur, but whether the phenomenon is related to gas fracturing is another matter. Like so much in science, the answer is rather complex.

To begin with, remember that drinking water wells are not deep. The deepest well in a private yard is no more than a couple of hundred meters. The rest are much smaller. Hydraulic fracturing occurs at kilometer depths. In most cases, the aquifer is separated from the fractured shale formation by several rock formations of various types. As a result big difference depths, aquifer, and gas-bearing formation communicate very little, if at all.

However, burning water is a proven fact. Where does methane get into the water, if not from fracking? The phenomenon is common throughout the world and happens where a well is dug in a gas-bearing area. Natural gas occurs at various depths, including at shallow depths. Natural gas can always be expected to seep into wells in certain regions. But even gas production without hydraulic fracturing can lead to gas ingress into the aquifer.

  • First, changes in reservoir pressure can cause gas to move from a high pressure zone to a low pressure zone.
  • Second, poorly plugged gas wells can and do leak gas. These poorly plugged wells are on the conscience of people whose duty it is to do their job reliably.
  • Thirdly, long-abandoned wells will no longer be serviced and clogged again.

As you can see, none of these problems is related to the production of shale gas by hydraulic fracturing.

When the Colorado Oil & Gas Conservation Commission investigated a case of burning water in a well that was widely used in Gasland, they found that the water contained gas bubbles and the naturally occurring methane in the water had nothing to do with his prey. The well is dug directly into the gas-bearing layer. However, Gasland demonstrates the phenomenon as a consequence of shale gas fracturing, which is not true.

The owner of the well is struggling with the problem. The simplest and most effective method is to ventilate the well. Methane is almost half the weight of air, well ventilation has been used effectively long before fracking was invented.
It is an established fact that methane in well water is more common in places where the hydraulic fracturing method is used. In 2011, a widely published study by Duke University found that when gas well located about a kilometer from the well, the water in the well contains methane 17 times higher than the average. But when the big headlines draw attention to the causal link, there is no doubt that this is how natural gas production and methane content in well water are related.

In places of natural gas deposits:
  • Gas is necessarily present in the water of wells.
  • Gas companies come to extract gas.

The study mentioned above says that there is no data on the content of methane in the water of wells before the application of the hydraulic fracturing method, thus it cannot be argued that it was the emergence of gas companies that led to the appearance of methane in the water. The study says that 13% of wells have elevated levels of methane in the water and should be ventilated.

What about the claim that shale gas fracturing involves injecting hundreds of toxins into the ground? Yes, it is true, in part. And not the way it's presented. The main chemical element in fracking is water, which makes up 98.5% of the composition injected into the ground. About 1% of the composition is "proppant" of various types, usually sand. The type of "proppant" is selected based on specific geological conditions. The remainder of the slurry percentage changes all the time and consists primarily of drilling lubricants and sand slugging compounds. The goal of hydraulic fracturing is to get sand grains into the cracks created by the water pressure and keep the cracks open. Without good lubricants, surfactants and suspensions like guar gum, the sand gets stuck in the cavities and doesn't reach the target. Depending on the type of rock, these 0.5% solution and acids can be included, which affect the permeability of the rock. In the composition of the same 0.5%, one can find corrosion inhibitors, which are introduced to increase the corrosion resistance of pipes, as well as bactericidal preparations against corrosive bacteria. A complete list of ingredients for fracking is widely available on the English Web, as required by law, and anyone interested should see it. A great place to start is to search for "fracking fluid disclosure".

If you live in the USA and are concerned about the composition of the fracturing fluid in a particular well in a particular area, the author recommends the FracFocus website, which will provide comprehensive information. Including exact indication of the type of sand and other components used. FracFocus partners with the natural gas industry and the Groundwater Protection Council in cooperation with local regulators.

When we talk about corrosion inhibitors, benzene, guar gum, any resident of the region should show interest. So who to believe?
  • Movement activists who claim that chemicals go straight into drinking water?
  • Or geologists and regulators who claim that the two fluids in question do not intersect anywhere?

It is quite difficult for an ordinary person to understand who is telling the truth. The author asked a friend from Pennsylvania who is a geologist for an official regulatory organization, who immediately appreciated the seriousness of the issue. In Pennsylvania, shale gas production by hydraulic fracturing is very active. The Gasland film is clearly an unacceptable source of information and the gas companies avoid honestly recognizing the risks of further investment. Both sides have serious propaganda motives. The consensus on the issue seems to be an unbiased source of information: the Defense Agency Environment United States (US Environmental Protection Agency). If you hate the Halliburton mining company, as many do, you will love the EPA. The EPA released a statement online to Halliburton due to failure to provide full information about technological process drilling. In response, Halliburton publicly drank a glass of fracking solution at an industry conference. If you want to get independent basic knowledge of gas fracturing technology, you can do self-education right now. There are enough sources, including the official EPA website.
At the time of this writing, the EPA is undertaking an ambitious study of groundwater safety that could be affected by fracking. Unfortunately, the investigation is moving at government speed and is scheduled for a 2014 report. The good news is that the EPA must document any confirmed groundwater contamination from hydraulic fracturing. Even the aforementioned Duke University study found no traces of fracking fluid in the wells. However, many cases of water pollution by accidental leaks of liquids on the ground surface have been recorded. This happens all the time with every company transporting or pumping liquids.

Several states have banned the use of hydraulic fracturing until all circumstances are clarified, but the EPA has not given a single reason to stop fracking shale gas production in the United States. Like many other technologies, fracking is of great economic and political importance. Consequently, it causes violent emotions of the disputing parties. You choose. Or take a stormy part, becoming the defense of one of the parties. Or to study, for starters, the scientific information accumulated to date on the method of hydraulic fracturing.
The importance of resource extraction, energy independence or the income of gas companies have nothing to do with science. Let the interested parties think about it. And let science determine the safety of fracking for society.

Translation Vladimir Maksimenko 2013

 

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