For 65 years, hydraulic fracturing, just one of the known methods of intensifying hydrocarbon production, did not have such a resonant significance, which it acquired in recent years in European countries and Ukraine and is now inextricably linked with shale gas production. However, this technology was known in the territory former USSR long before the start of industrial production of shale gas in the United States at the beginning of this century. In the post-Soviet space, Russia is the leader in the use of hydraulic fracturing, second only to the United States in the number of operations on a global scale.
Surprisingly, but true: today hydraulic fracturing is prohibited only in those countries where gas is not produced in principle: France, the Czech Republic, Bulgaria. By a strange “coincidence” of circumstances, the Russian Federation is the main supplier of gas for these countries. With Ukraine, the story is different: the country produces ~20 billion cubic meters of gas per year (providing ~40% of the demand), and thanks to the presence of reserves, plans and projects for gas production from unconventional sources (sandstones, shale, coal seams, etc.) reduce gas dependence on Gazprom.
For many years, Russia was a monopoly supplier of gas to Ukraine, which is now developing projects to diversify gas supplies, incl. through the production of shale gas in domestic fields. Only in the last two years, thanks to savings and energy efficiency, Ukraine has managed to significantly (from 40 to 30 billion cubic meters) reduce the import of Russian gas, while increasing its own production is seen as an effective way to get rid of excessive gas dependence on Gazprom. .
Due to the reduction in the volume of imports of Russian gas to Ukraine, such initiatives of the country naturally do not cause optimism among the Russian gas monopolist, which is already losing its position in gas market Europe due to the shale revolution in the USA. Russia does not yet plan to search for its own shale gas, but is not against exploring the possibility of extracting shale oil, while still widely using hydraulic fracturing in its oil fields.
Shale gas: Gazprom’s position
After the obviously positive results of the USA, when significant additional volumes of gas were obtained precisely through the development of shale (in 2009, 67 billion cubic meters of shale gas were produced, i.e. ~11.3% total production gas in the USA), Gazprom began to monitor the development of the shale gas industry. Now, annually in the 4th quarter, the monopoly publishes a report on monitoring this industry.
In the fall of 2010, based on the results of the first year of monitoring, it became known that Gazprom has own technologies, similar to those used in shale gas production, and used them in coal gas production in Kuzbass (Gazprom, 10.29.2010 http://www.gazprom.ru/press/news/2010/october/article104865/).
A 2011 release indicated that the Russian gas monopoly was studying the shale issue in regional markets, and in 2012, Gazprom focused on the negative experience of the development of this industry in Europe, in particular, it noted the issuance of bans on hydraulic fracturing in a number of countries.
“...Gazprom has its own technologies for developing shale gas...” points out Igor Yusufov, a member of the Gazprom Board of Directors, founder of the Energy Fund, former Minister of Energy of Russia in 2001-2004. (Article “Shale gas is a loss-making business and a very harmful thing for the environment,” April 25, 2013). However, Gazprom does not see the need to develop its own shale formations, because believe that 28 trillion cubic meters natural gas, which are on the company’s balance sheet, are quite enough for decades to meet internal needs Russian economy and fulfillment of obligations to partners in the CIS and abroad.
Thus, in Russia there is currently no strategic need to rely on shale gas, especially in conditions of excess natural gas production and a catastrophic decline in the volume of its supplies abroad. However, in particular, the recent purchase of TNK-BP by Rosneft, according to some Ukrainian geologists, is due, first of all, to the strategic interests of acquiring the technologies achieved by TNK-BP in the production of hard-to-recover hydrocarbons, incl. unconventional gas resources.
At the same time, hydraulic fracturing is being widely developed by Russian oil companies, including Gazprom Neft (formerly Sibneft) - affiliated undertaking Gazprom, where he owns 95.68% of the shares.
In particular, on April 8, 2013, Gazprom Neft and Royal Dutch Shell plc signed a Memorandum of Confirmation of the General Partnership Agreement in the field of exploration and production of shale oil. The parties will create a joint venture that will engage in new projects for the exploration and development of oil shale in the Khanty-Mansiysk Autonomous Okrug
Hydraulic fracturing is a technology that ensures Russia's leadership in the global oil market
Russia widely uses hydraulic fracturing to produce oil (gas is still flowing on its own), and large quantity Hydraulic fracturing is used only by the United States, and Russia confidently ranks second in the world. So far there are no big problems with gas production, but with oil not everything is so good. The laurels of the long-time leader in oil production apparently haunt Russia, which has been trying to impose rivalry with Saudi Arabia for several years. Over the past few years, this has been done in fragments, as well as based on the results of individual months (Fig. 1).
Despite the high global price, oil, as the main energy resource in the global energy balance (oil - 33%, coal - 30%, gas - 24%), still competes disproportionately high prices for Russian gas. Russia continues to use the linking of its own gas prices to a basket of petroleum products, but this is becoming more of a special case, because many countries are moving away from this link, giving preference to trade in centers specializing in gas trading (exchange, hubs).
Only through the use of multi-stage hydraulic fracturing and horizontal drilling technology does Russia still manage to increase oil production. These are the same technologies that the United States uses to extract shale gas and oil.
Russian companies so far carry out 8-stage hydraulic fracturing, while Western companies carry out up to 40 stages, with an average of 20 stages. In July 2013, the American company NCS Oilfield Services carried out a 60-stage hydraulic fracturing on a well in Canada, which set a new record. In terms of oil reserves, Russia ranks 8th in the world, behind several OPEC countries and Canada. Russia's proven oil reserves are 3-4 times smaller (Fig. 2) than those of Saudi Arabia, the world leader in oil production, but despite this, Russia extracts volumes comparable to the Kingdom. Most of The extracted oil is exported, which provides a significant share of financial revenues to the country.
With obviously different opportunities and conditions for oil production, the race for leadership between Saudi Arabia and the Russian Federation continues. That is why leading Russian companies, incl. Gazprom enterprises are working on and improving methods for increasing (intensifying) hydrocarbon production in the oil industry, including hydraulic fracturing (or what is called fracking).
Hydraulic fracturing is sweeping across Russia
“...Russia is one of the largest consumers of hydraulic fracturing services both for intensifying oil production and increasing oil recovery,” - Gazprom Neft, December 5, 2012.
Since 1985, specialized companies were created in Russia, which subsequently carried out thousands of hydraulic fracturing operations annually. For most developed wells, hydraulic fracturing has become a necessary part in the oil production process. Hydraulic fracturing is most effectively used in Russian wells with reservoirs characterized by low permeability. Very often, only through the use of hydraulic fracturing is it possible to achieve a profitable level of well production. In Siberia, 500 well operations are carried out annually. Even at the turn of 2005, more than 40% of the structure of reserves for oil production in Russia was located in reservoirs with low permeability, and in the future they were expected to increase to 70%. Therefore, much attention was paid to the prospects for using hydraulic fracturing. (Y.D. Kachmar, V.M. Svitlitsky and others. “Intensification of the tide of carbohydrates in the Sverdlovian region.” - Lviv, 2005. - 414 pages.)
In the recent past, private oil companies Yukos and Sibneft used the hydraulic fracturing method in their fields, but this information was not available to the wider international public.
In March 2013, at the CERA Week conference (Houston, Texas, USA), Russian oil companies told the world about their achievements and plans to use hydraulic fracturing to increase production in old fields. In particular, oil companies reported:
Over the next three years, Gazprom Neft, together with Shell, will begin developing reservoirs that are similar in their geological structure to the Bakken shale field (USA). Rosneft and Exxon Mobil will also take part in the project;
Rosneft plans to use hydraulic fracturing at 50 wells in 2013 (3 in 2012); Lukoil did not use hydraulic fracturing until 2011, but by the beginning of 2013 the company already had 215 horizontal wells, and in three years their number will be increased to 450;
In open sources it is not difficult to find more impressive figures for the use of hydraulic fracturing by Russian oil companies.
In 2012, Gazprom Neft drilled 68 horizontal wells, 19 of them using multi-stage hydraulic fracturing (up to 6 stages). Until 2013, Gazprom Neft had already carried out 2.5 thousand hydraulic fracturing operations. ~500 hydraulic fracturing operations are carried out annually, and the company does not yet plan to reduce this figure.
For 2013, it was planned to drill 120 wells, incl. 70 with multi-stage hydraulic fracturing. On July 10, 2013, Gazprom Neft for the first time carried out an 8-stage hydraulic fracturing at the Vyngapurovskoye oil and gas condensate field. The position of the largest Russian state-owned oil producing company regarding hydraulic fracturing becomes clear from the speech of the President of Rosneft OJSC I.I. Sechin at the CERA Week conference in Houston, Texas, March 6, 2013.
“...Rosneft strives to become a technology company. In production, we are already actively using methods such as multi-stage hydraulic fracturing in combination with horizontal drilling. The peculiarities of our deposits require the development and adaptation of formation stimulation technologies; we are conducting this program today with the participation of partners from Statoil and ExxonMobil. Our specialists widely use drilling of horizontal wells with a deviation from the vertical of up to 7 km, incl. on the shelf, and with effective wiring up to 1 km in layers only 3-4 meters thick. Low-permeability carbonate deposits are being developed using horizontal wells, incl. multi-barrel…” noted I. Sechin.
In particular, in early November 2006, at the Priobskoye oil field, operated by RN-Yuganskneftegaz LLC (a subsidiary of Rosneft, which gained control over the main asset of YUKOS - Yuganskneftegaz), with the participation of specialists from Newco Well Service The largest hydraulic fracturing of an oil reservoir was carried out in Russia. The operation lasted 7 hours and was broadcast on live via the Internet to the Yuganskneftegaz office. According to the data open sources, until May 2012, Yuganskneftegaz performed more than 10,000 hydraulic fracturing operations.
In 2009-2010 Rosneft remained the largest client of service companies for hydraulic fracturing, and currently ˃2 thousand hydraulic fracturing is done per year, and the vast majority of new wells are put into operation after hydraulic fracturing. NK Tatneft plans to carry out 579 hydraulic fracturing operations in 2013 (376 in 2012). During the first half of the year, the company Tatneft-RemService LLC carried out 309 hydraulic fracturing operations for Tatneft, which is 113 more than in 6 months of 2012 (“Oil of Russia”, 07/31/2013)
From annual report In 2012, NK Lukoil became aware that the company actively uses hydraulic fracturing in its work. “In 2012, investing in high-tech development methods, such as horizontal well drilling and hydraulic fracturing, allowed the Company to bring additional reserves into development in the North Caspian Sea and the Komi Republic...”
“The breakthrough technologies of NK Lukoil, introduced in 2012, include drilling horizontal wells with multi-stage hydraulic fracturing. In 2012, 99 wells with multi-stage hydraulic fracturing were commissioned. The average oil flow rate is 43.5 tons/day. If in 2011 multi-stage hydraulic fracturing technology was used only in Western Siberia, then in 2012 - and at the fields of LLC LUKOIL-PERM, LLC LUKOIL-Komi .... “...in 2012, the Lukoil Group performed 5,605 EOR (enhanced oil recovery) operations, which is 15% higher than the 2011 level. In 2012, additional production due to the use of EOR methods in Russia amounted to 23.1 million tons. The main volume of additional production (˃15.1 million tons) was obtained through physical methods, primarily through hydraulic fracturing...”
“In 2012, 867 hydraulic fracturing operations were carried out at the Group’s fields with an average increase in oil production rate of 8.1 tons per day. Almost 8 million tons of oil were produced using other EOR methods - hydrodynamic, thermal, chemical, and production intensification. In 2012, the active implementation of the latest chemical technologies(1,602 operations were carried out versus 1,417 in 2011),” Lukoil reports to shareholders.
The results, as well as the work plans of Russian oil companies, indicate that they are unlikely to change their attitude towards hydraulic fracturing in the near future, through which significant volumes of oil production are ensured. Hydraulic fracturing is also actively used in gas fields, but for obvious reasons, information about this is more closed.
The long-term partner of Gazprom, the German concern BASF, reported on the use of hydraulic fracturing in Russian gas fields. In particular, they were talking about the company Achimgaz (a joint venture of Gazprom and Wintershall), which uses hydraulic fracturing technology in Urengoy: “... our subsidiary Wintershall, observing strict safety standards and environmental regulations, has been using this technology in production for several decades oil and especially gas in Russia, Argentina, the Netherlands and Germany. Until now, there has not been a single case of groundwater contamination,” Harald Schwager, a member of the Board of Executive Directors of BASF SE responsible for the oil and gas business, is quoted by the Frankfurter Allgemeine newspaper. The main thesis of BASF and H. Schwager, in particular: “... fracking technology in the future will become widespread in different parts of the world, its active use will seriously change the energy supply system and energy prices.”
Who carries out hydraulic fracturing in Russia
Services for hydraulic fracturing in Russia are mainly provided by Western specialized service companies. The fleet of hydraulic fracturing equipment available in Russia belongs to both specialized service companies and service divisions of Russian oil and gas producing companies. Largest quantity Hydraulic fracturing is carried out in Russia by Trican Well Service, Surgutneftegaz, KATKO oil, Schlumberger, CalFrac, TatRemServis, MeKamiNeft, Weatherford, Halliburton and a number of other companies. In February 2013, Tatneft acquired a new, second fleet for hydraulic fracturing, which produced in Belarus under license from the “American” company “NOV Fidmash” (“Oil of Russia”, 02.25.2013).
Only at the end of May 2013, tests of the latest domestic equipment for hydraulic fracturing of oil and gas formations were completed in Russia.
The widespread use of hydraulic fracturing in Russian oil and gas fields has been the most pressing topic in the industry over the past few years. Increasing need Russian companies in the use of hydraulic fracturing was predicted by experts several years ago. The development of a high-performance hydraulic fracturing technological complex was ordered by the Ministry of Education and Science Russian Federation in 2011 within the framework of the federal target program “Research and development in priority areas of development of the scientific and technological complex of Russia for 2007-2013.”
Advanced technical solutions are based on military developments. The productivity of the hydraulic fracturing complex is determined by the power of the pumping unit, as well as the number of pumps involved in the hydraulic fracturing process. The latest Russian hydraulic fracturing technology uses a gas turbine power plant that develops power up to 2250 hp. and capable of maintaining it for a long time. Similar gas turbine engines are installed in Russian T80 and American Abrams tanks.
Starting from 2013, serial production of high-performance hydraulic fracturing complexes will be carried out by the RFK consortium, an association of Russian machine-building enterprises led by Russian Fracturing Company LLC. Today, in addition to PKB Avtomatika and Tikhoretsky, the consortium machine-building plant includes the mechanical engineering group PromSpetsServis. The cost of the RFK mobile complex is planned within 200-300 million rubles. (RFK website http://www.fracturing.ru/newsblender.html)
Hydraulic fracturing: from “useful invention” to “barbaric method”
While Rosneft is the largest client of foreign service companies for hydraulic fracturing, and Lukoil calls multi-stage hydraulic fracturing a breakthrough technology, the top management of Russia is forced to dissemble - dissociating itself from hydraulic fracturing.
The reason for this is the extensive anti-shale campaign across Europe and Ukraine, where hydraulic fracturing is positioned as an unsafe type of mining. There is also a Russian trace in support of precisely this position, albeit indirectly. This is most obvious in Bulgaria and Ukraine.
“Hydraulic fracturing was a useful Russian invention, but became a barbaric method of oil production,” concludes the head of East European Gas Analysis, Mikhail Korchemkin, based on the results of his own research: “Before becoming a “barbaric method” of oil production, this technology was considered a useful Russian invention, necessary for modernization and technical development economy of the country."
The basis for this conclusion was the official position of Russia: “... As for other methods of extracting oil itself using hydraulic fracturing and other rather barbaric methods, you understand what this leads to, specialists know this very well,” V. Putin said at the Commission meeting on the strategy for the development of the fuel and energy complex and environmental safety on February 13, 2013.
How does this position fit in with the plans of Russian oil companies regarding the further use of hydraulic fracturing in Russian fields? After all, without the use of hydraulic fracturing at its fields, Russia will lose its position as a world leader in oil production and budget revenues, because It was this method of intensifying production that allowed Saudi Arabia's leadership to be challenged for many years.
Some differences in the positions of the Russian Federation and Ukraine regarding shale gas and hydraulic fracturing as a method of its production are not immediately apparent: the Russian Federation does not support shale gas production, but full swing uses hydraulic fracturing at its oil fields. In Ukraine, shale gas production has received resonance, primarily due to fears of the consequences of using hydraulic fracturing, although in fact this method, like in Russia, has a long history of use. It is possible that, also thanks to the hydraulic fracturing method, in the 80s of the last century, Ukraine achieved previously unprecedented results in gas production.
Alexander Laktionov
Chief specialist in energy market research at Smart Energy, Ph.D.
From the history of the development of methods for intensifying oil production
The first attempts to intensify oil production from oil wells were made back in the 1890s. In the USA, 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 crush dense rocks in the bottomhole zone of the well and ensure an increase in the flow of oil to the bottom. The method was successfully used for some time, despite its obvious dangers.
Around the same time, a method was developed to intensify oil production by treating the wellbore zone with acid. The first acid treatments, according to some sources, were performed in 1895. The invention of the method is credited to Hermann Fresch, chief chemist at Standard Oil's Solar refinery. Fresh received a patent for acid treatment on March 17, 1896. It concerned a chemical agent (hydrochloric acid) that could react with limestone, resulting in the formation of soluble products. These products are subsequently removed from the formation along with well fluids.
As with all innovations, it took some time for this innovation to catch on. It took 30 years for all the benefits of acid treatments to be realized. The use of the method on an industrial scale began only in the 30s of the 20th century.
During these first intensifying acid treatments, it was discovered that pressure could cause formation rupture. 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 USA, after which their number began to increase sharply. By the mid-50s, the number of hydraulic fracturing operations carried out reached 3,000 per year. In 1988, the total number of hydraulic fracturing operations performed exceeded 1 million operations. And this is only in the USA.
In domestic practice, the hydraulic fracturing method began to be used in 1952. The peak use of the method was reached in 1959, after which the number of operations decreased and then stopped altogether. From the beginning of the 1970s to the end of the 1980s, hydraulic fracturing was not carried out on an industrial scale in domestic oil production. In connection with the commissioning of large oil fields in Western Siberia, the need to intensify production simply disappeared. The revival of the practice of using hydraulic fracturing in Russia began only in the late 1980s.
Currently, the leading positions in the number of hydraulic fracturing operations are occupied by the USA and Canada. They are followed by Russia, where hydraulic fracturing technology is used mainly in the oil fields of Western Siberia. Russia is practically the only country (not counting Argentina) outside the United States 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 prejudices and misunderstandings of the technology. In some countries, there are significant restrictions on the use of hydraulic fracturing technology, up to an outright ban on its use.
What is hydraulic fracturing?
The essence of the hydraulic fracturing method is to inject fluid under high pressure into the bottomhole zone, resulting in rock rupture and the formation of new or expansion of existing cracks. To keep the cracks open when the pressure decreases, a fixing agent, proppant, is pumped into them along with the liquid. The fluid that transfers pressure to the formation rock is called 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 cracks appear as a result of hydraulic fracturing to a depth of about 500 meters. At depths below 500 meters, vertical cracks appear. Since productive oil-saturated formations usually lie at a depth below 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 material that is pumped during the hydraulic fracturing process to prevent the closure of the created fracture. 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. Used in the case of carbonate formations. The network of cracks and cavities created using acid and high pressure does not require proppant fixation. It differs from conventional acid treatment in the much larger volume of acid used and the injection pressure (higher than the rock burst pressure).
The main factors on which the success of hydraulic fracturing depends:
- correct choice of object for operations;
- use of hydraulic fracturing technology that is optimal for given conditions;
- competent selection of wells for treatment.
Environmental safety of hydraulic fracturing
Large-scale use of hydraulic fracturing over a long period of time (more than 50 years) confirms the environmental safety of the method. Hydraulic fracturing work is carried out under the control of government regulatory bodies and supervisors of the oil companies themselves. Since oil reservoirs lie at great depths (1000-3000 m), the influence of the process on surface and ground water is excluded. Using several columns itself, it 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 managing reservoir development. Currently many oil fields They 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 industrially accessible precisely thanks to this technology. Experts estimate that hydraulic fracturing has contributed to an increase in recoverable oil reserves in North America by 8 billion barrels.
Along with the formation of cracks in the formation in order to increase the productivity of wells, hydraulic fracturing can also be used to overcome contamination of the bottomhole zone of the formation, as a means of increasing the efficiency of operations when implementing secondary methods of oil production, and to increase the injectivity of wells when burying salt solutions and industrial waste in underground formations .
The method consists of creating a highly conductive fracture in the target formation to ensure the flow of produced fluid (gas, water, condensate, oil or a mixture of them) to the bottom of the well. The hydraulic fracturing technology involves pumping fracturing fluid (gel, in some cases water, or acid in acid fracturing) into the well using powerful pumping stations at pressures higher than the fracturing pressure of the oil-bearing formation. To maintain the fracture open, a proppant (treated quartz sand) is used in terrigenous reservoirs; in carbonate reservoirs, acid is used, which corrodes the walls of the created fracture.
Typically, oil service companies (Halliburton, Schlumberger, BJ Services, etc.) specialize in hydraulic fracturing and other methods of intensifying oil production.
Criticism
Notes
see also
Links
- Intensification of oil production. Technical and economic features of methods / Sergey Veselkov // Industrial Gazette (Retrieved May 6, 2009)
Wikimedia Foundation.
2010.
See what “Hydraulic fracturing” is in other dictionaries: Same as Hydraulic Fracturing. Mountain encyclopedia. M.: Soviet Encyclopedia. Edited by E. A. Kozlovsky. 1984 1991 …
Geological encyclopedia Hydraulic fracturing - hydraulic fracturing, formation of cracks in gas, oil, water-saturated and other massifs rocks under the influence of liquid supplied into them under pressure. The operation is carried out in a well to increase the flow rate due to a branched... ...
Oil and Gas Microencyclopedia hydraulic fracturing using rubber balls and sand as proppants and water as the carrier fluid
- - Topics: oil and gas industry EN rubber balls sand water fracturing ... hydraulic fracturing using rubber balls and sand as proppants and oil as the carrier fluid - - Topics: oil and gas industry EN rubber balls sand oil fracturing ...
Technical Translator's Guide acid fracturing - - Topics: oil and gas industry EN rubber balls sand oil fracturing ...
- The process of formation/expansion and strengthening of cracks in a formation using acid-based fracturing fluid Topics oil and gas industry EN acid fracturing ... massive hydraulic fracturing (formation) - - Topics: oil and gas industry EN rubber balls sand oil fracturing ...
- - Topics: oil and gas industry EN massive hydraulic fracturing ...
Hydraulic fracturing (fracturing) is one of the methods for intensifying the work of oil and gas wells and increasing the injectivity of injection wells. The method consists of creating a highly conductive fracture in the target formation to provide inflow... ... Wikipedia acid fracturing of carbonate reservoir - - Topics: oil and gas industry EN rubber balls sand oil fracturing ...
- - Topics: oil and gas industry EN fracture acidizing... combined formation treatment (acid and hydraulic fracturing) - - Topics: oil and gas industry EN rubber balls sand oil fracturing ...
- — Topics oil and gas industry EN combined formation treatment … Same as Hydraulic Fracturing. Mountain encyclopedia. M.: Soviet Encyclopedia. Edited by E. A. Kozlovsky. 1984 1991 …
- (a. hydraulic seam fracturing, hydraulic slam rupture; n. Hydrafrac; f. fracture hydraulique de la couche; i. fracturacion hidraulica de las capas) formation of cracks in massifs of gas, oil, water-saturated and other g.p., and also p.i.... ...
Not so long ago there was a lot of talk around hydraulic fracturing and many organizations opposed permission to conduct hydraulic fracturing. The main argument against hydraulic fracturing was the theory that hydraulic fracturing greatly pollutes underground sources of fresh water, to the point that water with gas impurities begins to flow from the tap, which can be set on fire, about which, by the way, a video was made that hit in many programs and news releases.
1. First, let’s figure out what hydraulic fracturing actually is, because many people don't know this. Traditionally, oil and gas have been produced from sandy rocks, which are highly porous. Oil in such rocks can migrate freely 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 goal of hydraulic fracturing is to enlarge these cracks (or create new ones), giving oil a clearer path to the well. To do this, a special solution (which looks like jellied meat) consisting of sand, water and additional chemical additives is injected into the oil-saturated shale layer under high pressure. Under high pressure of the injected liquid, shale forms new cracks and expands existing ones, and sand (proppant) prevents the cracks from closing, thus improving the permeability of the rocks. 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.
On the right in the photo is a block of manifolds, on the left are the trailer pumps, then the fittings and behind it the crane. The logging machine is on the left, behind the trailers. She can be seen in other photographs.
2. Hydraulic fracturing requires a fairly large amount of equipment and personnel. Technically, the process is identical regardless of the company carrying out the work. A trailer with a manifold block is connected to the well fittings. Pumping units are connected to this trailer to inject hydraulic fracturing solution into the well. A mixing unit is installed behind the pumping stations, near which a trailer with sand and water is installed. A control station is installed over this entire farm. A crane and a logging machine are installed on the opposite side of the reinforcement.
This is what the mixer looks like. The hoses going to it are water connection lines.
3. The hydraulic fracturing process begins in a mixer, where sand and water, as well as chemical additives, are supplied. All this is mixed to a certain consistency, after which it is fed into 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 into the well. The hydraulic fracturing process is not carried out in one approach, but occurs in stages. The stages are compiled by a team of petrophysicists based on acoustic logging, usually of an open hole, carried out during drilling. During each stage, the logging team places a plug in the well, separating the hydraulic fracturing interval from the rest of the well, and then perforates the interval. Then the interval is hydraulically fractured and the plug is removed. At the new interval, a new plug is installed, perforation is carried out again, and a new hydraulic fracturing interval is performed. The hydraulic fracturing process can last from several days to several weeks, and the number of intervals can reach up to hundreds.
Pumps connected to the manifold block. The “booth” in the background is a control point for the operation of the mixer. The opposite view from the booth is in the second photo.
The pumps used for 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, at bandwidth 5-6 barrels per minute. The number of pumps is calculated by the same petrophysicists based on logging. The required pressure for fracturing the formation is calculated, and on its basis the number of pumping stations is calculated. During operation, the number of pumps used always exceeds the calculated number. Each pump operates at a less intensive mode 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, pump failure does not affect the hydraulic fracturing process. This is very important, because If the process has already started, then stopping is unacceptable.
5. Current hydraulic fracturing technology was not born yesterday. The first attempts at hydraulic fracturing were made back in 1900. The nitroglycerin charge was lowered into the well and then detonated. At the same time, acid stimulation of wells was tested. But both methods, despite their early birth, still required a lot of time to become perfect. Hydraulic fracturing boomed only in the 1950s, with the development of proppant. Today the method continues to be refined and improved. When stimulating a well, its life is extended and its flow rate increases. On average, the increase in oil flow to the calculated well flow rate is up to 10,000 tons per year. By the way, hydraulic fracturing is also carried out on vertical wells in sandstone, so it is a mistake to think that the process is only acceptable in shale rocks and has just been born. Today, about half of the wells undergo hydraulic fracturing stimulation.
View of the manifold block from the valves. By the way, you can only walk among trailers and pipes during logging, when there is no pressure in the injection system. Any person who appears among the trailers with pumps or pipes during hydraulic fracturing is fired on the spot without talking. Safety first.
However, with the development of horizontal drilling, 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 conducted. If you read all these articles, then everything is complicated, but this is only at first glance, but we will take a closer look at the details.
Logging machine. The team collects the charges and prepares the plug for the perforation.
The most important argument against hydraulic fracturing is the contamination of groundwater with chemicals. What exactly is included in the solution is a company secret, but some elements have been disclosed and are available in open public sources. Just turn to the FrakFocus hydraulic fracturing database and you can find general composition 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 for humans. Examples of specific additives are: Ammonium persulfate, Hydrochloric acid, Myriatic acid, Ethylene glycol.
8. How can these chemicals rise to the top bypassing the traps that hold the oil? We find the answer in a report from the Environmental Defense Association (3). This can happen either due to explosions at wells, or because of spills during hydraulic fracturing, or because of spills in disposal pools, or because of problems with the integrity of wells. The first three reasons are not able to infect water sources over large areas; only the last option remains, which today is officially confirmed by the US Academy of Sciences (4).
9. For those interested in how the movement of fluids inside rocks is monitored, this is done using so-called tracers. A special liquid with a certain background radiation is injected into the well. After that, sensors that respond to radiation are installed in neighboring wells and on the surface. In this way, it is possible to model very accurately the “communication” of wells with each other, as well as detect leaks inside the well casings. Don't worry, the background of such liquids is very weak, and the radioactive elements used in such studies decompose very quickly without leaving any traces.
10. Oil rises to the surface not in its pure form, but with admixtures 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. Speaking in simple language- waste is pumped back into the ground. The casing is cemented, but it rusts over time and at some point it develops a leak. If the pipe has good cement in the annulus, then 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 fluids from the well will enter the annulus, from where they can get anywhere, i.e. .To. the leak may be higher than 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 fracking group. Back when many companies created separate departments within themselves responsible for the integrity of wells and their inspection. Leaks can bring with them a lot of dirt, gas (not only natural, but also hydrogen sulfide) into the upper layers of rocks. heavy metals and are capable of contaminating clean water sources even without hydraulic fracturing chemicals. Therefore, the alarm raised today is very strange; the problem existed even without hydraulic fracturing. This is especially true for old wells that are more than 50 years old.
11. Today, regulations in many states are changing very quickly, especially in Texas, New Mexico, Pennsylvania and North Dakota. But to the surprise of many, it was not because of hydraulic fracturing at all, but because of the explosion of the BP platform in the Gulf of Mexico. In many cases, companies rush to conduct logging tests to check the integrity of the casing and the cement behind it, and submit this data to government commissions. By the way, it should be noted that so far no one is officially requiring well integrity logging, but companies spend money on their own and do this work. If the condition is unsatisfactory, the wells are shut down. To the engineers' credit, for example, out of 20,000 wells inspected in Pennsylvania in 2008, only 243 cases of leakage into the upper water layers were reported (5). In other words, hydraulic fracturing has nothing to do with contamination and gasification of fresh waters; the reason for this is the poor integrity of wells that were not plugged in time. And there are a lot of toxic elements in oil-saturated formations without chemical additives used during hydraulic fracturing.
Another argument that opponents of hydraulic fracturing give is the monstrous amount of fresh water required for the operation. Hydraulic fracturing really requires a lot of water. A report from the Environmental Defense Association estimates that a total of 946 billion liters of water were used from 2005 to 2013, with 82,000 hydraulic fracturing operations carried out during this time (6). The figure is interesting, if you don’t think about it. As I mentioned before, hydraulic fracturing has been widely used since the 50s, but 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. Answer to this question, in part, can be found in the same hydraulic fracturing database "FracFocus" - 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 does not talk about this. Probably because 82 thousand operations somehow pale in comparison to a million.
This is what proppant looks like. It is called sand, but 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 can be different types. Typically, identification is proportional to the grains of sand, for example this is 16/20 proppant. In a separate post directly about the hydraulic fracturing process, I will go into detail about the types of proppant and show its different types. And they call it sand because during the first hydraulic fracturing, the Halliburton company used ordinary fine river sand.
There are also many questions for the EPA (Environmental Protection Agency). Many people like to cite the EPA as a very compelling source. The source is indeed weighty, but even a weighty source can give misconceptions. At one time, the EPA made a splash all over the world, the problem is that having made a splash, few people know how it all ended, and the story ended very badly, for some.
On the right is the mixer bucket. On the left is a container with proppant. The proppant is fed into a bucket on a conveyor belt, after which a mixer takes it into a centrifuge, where it is mixed with water and chemical additives. After which the gel is supplied to the pumps.
There are two very interesting stories related to EPA (8). So, the first story.
In a suburb of Dallas, in the city of Fort Worth, an oil company was drilling wells for gas production, naturally using hydraulic fracturing. In 2010, the regional director of the EPA, Dr. Al Armendariz, filed an emergency lawsuit against the company. The lawsuit stated that people living near the company's wells are in danger because... The company's wells gasify nearby water wells. At that moment, the intensity of passions around hydraulic fracturing was very high, and the patience of the Texas Railroad Commission exploded. For those who have forgotten, in Texas the Railroad Commission deals with land use and drilling issues. A scientific group was formed and sent to study the water quality.
The upper methane in near Fort Worth is located 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 carried out at the company’s wells was carried out at a depth of 1,500 meters. So, it turned out that the EPA did not conduct any tests to study the harmful effects, but simply went ahead and declared that hydraulic fracturing pollutes fresh water, and filed a lawsuit. And the commission took and conducted tests. Having checked the integrity of the wells, taken soil samples and carried out the necessary tests, the commission issued a single verdict - not a single well has leaks and has nothing to do with fresh water gasification. The EPA lost two courts, the company and the second court directly to the Railway Commission, after which the director of the EPA, Dr. Al Armendariz, resigned "by at will".
By the way, there really is a problem with water gasification, but it has nothing to do with hydraulic fracturing, but is connected with the very shallow occurrence of methane. Gas from the upper layers gradually rises to the top and enters water wells. This is a natural process that has nothing to do with production and drilling. Not only water wells, but also lakes and springs are subject to such gasification.
Immediately after the story with the careless doctor from the EPA, the railway commission turned its attention to a very popular video, which by that time had not been shown anywhere. One Steven Lipsky, a fresh water well owner, and environmental consultant Alice Rich made a video in which they set fire to tap water. Water was drawn from Stephen's water wells. The water caught fire, allegedly due to a high concentration of gas, which was the fault of the oil company with its ill-fated hydraulic fracturing. In fact, upon 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 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 transmit deliberately false data to the EPA and there was a conspiracy between Alice and Stephen to slander the company's activities. Again, the company and the fracking process have been proven to be environmentally friendly. After this incident, by the way, everyone became somewhat embarrassed about the accusations of hydraulic fracturing in water gasification. Apparently no one is in a hurry to go to jail. Or did everyone immediately understand that this process was natural and existed before the advent of hydraulic fracturing?
So, to summarize all of the above - any human activity harms the environment - no exception. Hydraulic fracturing itself is environmentally friendly and has been used on a large scale in industry for over 60 years. Chemical additives pumped to great depths during hydraulic fracturing do not pose any threat to the upper water layers. The real challenge 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 formations even without hydraulic fracturing. The gasification process itself is natural and they knew about this problem even without hydraulic fracturing; they struggled with this problem even before hydraulic fracturing.
Today, the oil industry is much cleaner and greener than at any time in history, and continues to struggle to preserve the environment, and many of the stories and anecdotes come from very unscrupulous officials. Unfortunately, such stories very quickly remain in the memory of most people, and are very slowly refuted by facts that few people are interested in.
We must also not forget that the war with oil companies was, is and will always be, and cheap gas in huge volumes is not to everyone’s liking.
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. The top gas deposits are called Devonian, while the deep shale gas deposits 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 north of the state, a single verdict was given - there is no shale gas in the water wells, but methane and ethane from the upper Devonian layer. Gasification of wells is natural and associated with geological processes, identical to the problem in Texas. The hydraulic fracturing process does not contribute in any way 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 United States in general, many, many documents have been preserved, going back to the early 1800s, which mention burning streams, as well as flammable sources of water with abundant concentrations 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! A lot of documents indicate very high concentrations of methane in rivers and streams, more than 10 mg/L. Therefore, unlike Texas, where I personally have not heard anything about such documents, in Pennsylvania the problem of gasification was documented even before the start of any drilling at all. Therefore, what harm are we talking about from 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? For some reason, organizations fighting against hydraulic fracturing forget about such documents, or do not engage in such research and are not interested.
It is also worth noting that Pennsylvania is one of the states that requires operators to test the quality of fresh water under Act 13 before drilling to monitor the level of possible contamination. So, when analyzing water quality, almost always the permissible concentration of dissolved gas, 7000 μg/L, is exceeded. The question is, why then did people not complain about the state of health, the environment and the ruined land for two hundred years, but suddenly they suddenly realized they were complaining en masse with the start of gas drilling? (9).
Gasification is natural and is not a consequence of hydraulic fracturing or drilling in general; this problem exists in any country with gas deposits on the surface.
Today, shale gas extraction by hydraulic fracturing, or fracking for short, has found itself on the list of technologies that are popularly disliked. Fracking is a method of injecting water at high pressure to extract natural gas from a cracked formation. Hydraulic fracturing is widely criticized around the world as a dangerous method, which is even banned in a number of countries. Hydraulic fracturing has been accused of using toxic components that pollute the environment and causing earthquakes. Opponents of the method argue that hydraulic fracturing will result in pollution drinking water methane to an explosive state. And toxin pollution will cause unknown diseases. Sound scary? Still would!
Hydraulic fracturing is an excellent target to which a skeptical eye should be cast.
In 2010, the film Gasland challenged the public with incriminating statements about more than just fracking. The film painted an eerie picture of secrecy, the thirst for profit at any cost and the thoughtless pollution of all living things around by companies extracting underground resources. The mining companies responded with a web page, Debunking Gasland, and other publications that not only refuted the claims, but also attacked the film's producer as an activist in the movement. As was said in response to the film, the statements were made without geological expertise and experience in drilling wells. Which of the opposing sides should you believe? a common person from the street? Unfortunately, you have to listen to either the opponents of fracking or the supporters. Less often or never has a person on the street dispassionately analyzed the pros and cons of fracking based on scientifically proven facts.
Natural gas is found in shale or coal formations 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 quantities of shale gas. In these deep, tight rocks, it makes sense to use hydraulic fracturing to extract shale gas. The shale layer is usually no thicker than one hundred meters, so wells are drilled horizontally to a depth of about one kilometer and a pipe is installed, thereby creating the opportunity to create a hydraulic lever. By pumping water into a small hole in a pipe, you can create a pressure of up to 700 atmospheres and influence a wide area. The pressure breaks the formation into many cracks of about 1 mm, allowing the shale gas to leave its home. Hydraulic fracturing involves injecting water containing sand, this is the essence of the whole method. Sand particles fall into microcracks, expanding them to the point where gas can escape. Next, extraction wells are installed, and the production process becomes much more productive, since gas now has enough ways to leave deep layers.
Although hydraulic fracturing has been used since the early 1950s, widespread shale gas extraction began in the 2000s. About 90% of wells in the United States are produced by hydraulic fracturing. Fracking brings economic and political benefits to the country as a result of increased energy production.
So, what problems arise from the use of hydraulic fracturing? 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 can be set on fire with a match. Burning water does occur, but to what extent the phenomenon is related to gas production by hydraulic fracturing is another question. Like many things in science, the answer is not simple.
To begin with, we 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 various types. As a result of the large difference in depth, the aquifer and gas-bearing layer communicate with each other very little, if at all.
However, burning water is a proven fact. Where does methane get into water if not from fracking? The phenomenon is common throughout the world and occurs where a well is dug in a gas-bearing area. Natural gas occurs at different depths, including shallow depths. Natural gas can always be expected to seep into wells in certain regions. But gas production without hydraulic fracturing can lead to gas entering the aquifer.
- First, changes in pressure in the formations can force gas to move from an area of high pressure to an area of low pressure.
- Secondly, poorly plugged gas wells can and do leak gas. These poorly plugged wells are the responsibility of people whose responsibility is to do their job reliably.
- Thirdly, long-abandoned wells will no longer be serviced or plugged again.
As we can see, none of the listed problems are related to shale gas production using hydraulic fracturing.
When the Colorado Oil & Gas Conservation Commission investigated burning water in a well that was widely used in Gasland, they found that the water contained gas bubbles and that naturally occurring methane was not related to his prey. The well is dug directly into the gas-bearing layer. However, Gasland demonstrates the phenomenon as a consequence of shale gas extraction by hydraulic fracturing, which is not true.
A well owner is struggling with a problem. The simplest and most effective method This is the ventilation of the well. Methane is almost twice as light as air; well ventilation has been used effectively since long before fracking was invented.
It is an established fact that methane in well water is more common in areas where hydraulic fracturing is used. In 2011, a widely published Duke University study found that when a gas well is located about a kilometer from a well, the water in the well contains 17 times the average amount of methane. But when big headlines draw attention to a cause-and-effect relationship, there is no doubt that this is exactly how natural gas production and methane content in well water are connected.
In natural gas fields:
- Gas is necessarily present in well water.
- Gas companies come to extract gas.
The study mentioned above says that there is no data on the methane content of well water before the use of hydraulic fracturing, so it cannot be said 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 high levels of methane in their water and should be aerated.
What about the claim that hydraulic fracturing for shale gas involves injecting hundreds of toxins into the ground? Yes, this is true, partially. And not the way it is presented. Main chemical element in fracking, this 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 remaining percentage of the solution varies all the time and consists mainly of drilling lubricant and sand mobility compounds. The goal of hydraulic fracturing is to force grains of sand into cracks created by water pressure and keep the cracks open. Without good lubricants, surfactants and suspensions such as guar gum, sand will clump in cavities and fail to reach its target. Depending on the type of rock, this 0.5% solution may contain acid, which affects the water permeability of the rock. In the same 0.5% you can find corrosion inhibitors, which are introduced to increase the corrosion resistance of pipes, as well as bactericidal preparations against corrosive bacteria. The full list of fracking ingredients is widely available on the English-language 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 United States and are concerned about the composition of the fracking fluid in a particular well in a particular area, the author recommends the site FracFocus, which will provide comprehensive information. Including an exact indication of the type of sand and other components used. FracFocus partners with the natural gas industry and the Groundwater Protection Council in collaboration with local regulators.
When we talk about corrosion inhibitors, benzene, guar gum, anyone from the region should take an interest. So, who to believe?
- To the movement activists who claim that chemicals end up directly in drinking water?
- Or the geologists and regulators who claim that the two fluids mentioned 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 works as a geologist for an official regulatory organization, who immediately recognized the seriousness of the issue. In Pennsylvania, shale gas production using hydraulic fracturing is very active. The Gasland film is clearly an inappropriate source of information and gas companies are avoiding honest recognition of the risks of further investment. Both sides have serious motives for propaganda. The consensus on the issue seems to be an impartial source of information: the Protection Agency Environment USA (US Environmental Protection Agency). If you hate the Halliburton mining company, as many people do, you'll love the EPA. The EPA posted an online statement sent to Halliburton due to failure to provide complete information about technological process drilling Halliburton responded by publicly drinking a glass of fracking solution at an industry conference. If you want to gain independent basic knowledge of gas extraction technology using hydraulic fracturing, you can start educating yourself right now. There are plenty of sources, including the official EPA website.
At the time of this writing, the EPA is conducting a major study on the safety of groundwater that could be affected by fracking. Unfortunately, the investigation is moving at government speed and is scheduled to report in 2014. The good news is that the EPA must document any confirmed groundwater contamination resulting from hydraulic fracturing. Even the Duke University study mentioned above found no traces of fracking fluid in wells. However, many cases of water pollution due to accidental leaks of liquids onto the ground surface have been recorded. This happens all the time to every company that transports or pumps liquids.
Several states have banned the use of hydraulic fracturing until all the circumstances are clarified, but the EPA has not provided a single reason to stop fracking shale gas production in the United States. Like many other technologies, fracking has significant economic and political implications. Consequently, it causes strong emotions among the disputing parties. The choice is yours. Or take active part in defending one of the parties. Or study, for starters, accumulated for today scientific information about the hydraulic fracturing method.
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 degree of safety of fracking for society.
Translation by Vladimir Maksimenko 2013
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