GRP is more important than sanctions. Fracking or hydraulic fracturing: technology, history, equipment. New hydraulic fracturing technologies
These include new fracturing fluids, surfactants, hydrophobic agents and additives.
The TagraS-RemService company presented new technological solutions for hydraulic fracturing (fracturing) in difficult geological and technical conditions.
The company began to use a new low-viscosity fracturing fluid with good sand-carrying properties. Using this product allows you to:
1. Evenly place the proppant (proppant) along the height and length of the productive formation.
2. Control the growth of the crack in height (carrying out hydraulic fracturing on formations with weak barriers to water)
3. Reduce damage to the proppant pack after complete destruction of the gel (maintain fracture conductivity).
TagraS-RemService is working on laboratory testing of a new fastening material - modified sand. This product helps reduce the movement of water along the hydraulic fracture, in particular during hydraulic fracturing operations on highly water-cut wells. Sand has hydrophobic properties, is evenly distributed over the entire height of the crack and makes it possible to reduce the viscosity of the fracturing fluid.
The new technology of combined acid-proppant hydraulic fracturing based on acid gelled with surfactants (surfactants) shortens the process of well development and bringing the well into operating mode, and also reduces the risks of a forced shutdown of the process. The use of new chemical reagents prevents the polymer from entering the formation. At the same time, the amount of liquid pumped into the reservoir is reduced due to the fact that the cycle of pumping an aqueous polysaccharide gel with proppant is eliminated.
"TagraS-RemService" is also mastering the technology of hydrosand-jet perforation with further hydraulic fracturing. The main advantage of the new technical solution is the possibility of targeted impact on the formation without cutting off other perforation intervals, i.e. preliminary creation of a crack during hydrosandblasting perforation. Operations can also be performed on wells with low quality cement stone behind the column. This technology allows for multi-zone hydraulic fracturing in wells with horizontal completion.
In order to regulate the viscosity of the hydraulic fracturing fluid "on the fly" depending on the fraction and concentration of the proppant, it is proposed to use a new reagent - an anti-sedimentation additive, which allows:
1. Distribute the proppant evenly along the vertical crack.
2. Increase the sand-carrying capacity of hydraulic fracturing fluid.
3. Reduce gelling agent loading.
TagraS-RemService recently presented these developments at the Oil. Gas. Petrochemistry" within the framework of the Tatarstan Petrochemical Forum. President of Tatarstan Rustam Minnikhanov got acquainted with the company’s stand.
This technology, used to intensify 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 mining industry themselves. Meanwhile, the mixture that is pumped into a well during hydraulic fracturing consists of 99% water and sand, and only 1% chemical reagents.
What interferes with oil recovery
The main reason for low well productivity, along with poor natural permeability of the formation and poor-quality perforation, is a decrease in the permeability of the near-wellbore zone of the formation. This is the name of the area of the formation around the wellbore that is subject to the most intense influence of various processes that accompany the construction of the well and its subsequent operation and disrupt the initial equilibrium mechanical and physical-chemical state of the formation. Drilling itself changes 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 drilling fluid or its filtrate into the bottomhole zone of the formation
The reason for low well productivity may 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 zone of the formation also occurs during the operation of wells, 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, clogging the pore space of the reservoir. Intense contamination of the bottomhole formation zone is also observed as a result of the penetration of working fluids into it during various repair work in wells. The injectivity of injection wells deteriorates due to clogging of the pore space of the formation with corrosion products, silt, and oil products contained in the injected water. As a result of such processes, the resistance to filtration of liquid and gas increases, well flow rates decrease, and the need arises for artificial influence on the bottom-hole zone of the formation in order to increase the productivity of wells and improve their hydrodynamic connection with the formation.
Technologyfracking
To increase oil recovery, intensify the work of oil and gas wells and increase the injectivity of injection wells, the method of hydraulic fracturing or fracking is used. The technology consists of creating a highly conductive fracture in the target formation under the influence of fluid supplied into it under pressure to ensure the flow of produced fluid to the bottom of the well. After hydraulic fracturing, the well's production rate, as a rule, increases sharply, or the drawdown decreases significantly. Hydraulic fracturing technology allows you to “revive” idle wells that produce oil or gas traditional ways is no longer possible or unprofitable.
Hydraulic fracturing (HF) is one of the most effective means increasing the productivity of wells, since it leads not only to the intensification of the production of reserves located in the drainage zone of the well, but also, under certain conditions, allows to significantly expand this zone by introducing poorly drained zones and interlayers into production - and, therefore, to achieve higher final oil recovery .
Storyhydraulic fracturing method
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.
The first commercially successful hydraulic fracturing was carried out in 1949 in the United States, 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 total hydraulic fracturing operations performed exceeded 1 million, 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 this practice ceased altogether. From the beginning of the 1970s to the end of the 1980s, hydraulic fracturing in domestic oil production in industrial scale were not carried out. In connection with the commissioning of large oil fields Western Siberia the need to intensify production simply disappeared.
… And today is the day
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. Some of them have significant restrictions on the use of hydraulic fracturing technology, including an outright 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, using hydraulic fracturing, it is possible to solve specific problems, for example, eliminating sand in wells, obtaining information about the reservoir properties of test objects in exploration wells, etc.
IN last years The development of hydraulic fracturing technologies in Russia is aimed at increasing the volume of proppant injection, the production of nitrogen hydraulic fracturing, as well as multi-stage hydraulic fracturing in the reservoir.
Equipment forhydraulic fracturing
The equipment necessary for hydraulic fracturing is produced by a number of enterprises, both foreign and domestic. One of them is the TRUST-ENGINEERING company, which presents a wide selection of equipment for hydraulic fracturing in standard versions and in the form of modifications carried out at the request of the customer .
As competitive advantages products of TRUST-ENGINEERING LLC, it is necessary to note the high share of localization of production; application of the most modern technologies design and production; use of components and components from world industry leaders. It is important to note the high culture of design, production, warranty, post-warranty and service maintenance inherent in the company’s specialists. Equipment for hydraulic fracturing produced by TRUST-ENGINEERING LLC is easier to purchase due to the presence of representative offices in Moscow ( 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 mining industry, is not without certain disadvantages. One of the disadvantages of fracking is that the positive effect of the operation can be negated by unforeseen situations, the risk of which with such an extensive intervention is quite high (for example, an unexpected violation of the tightness of a nearby water reservoir is possible). At the same time. Hydraulic fracturing is today one of the most effective methods for intensifying wells, opening not only low-permeability formations, but also medium and high permeability reservoirs. The greatest effect from hydraulic fracturing can be achieved when implementing integrated approach to the design of hydraulic fracturing as an element of the development system, taking into account various factors, such as formation conductivity, well placement system, formation energy potential, fracture mechanics, fracturing fluid and proppant characteristics, technological and economic limitations.
IN Lately In oil production, hydraulic fracturing (fracturing) is increasingly being used. Hydraulic fracturing is one of the most effective methods of influencing the bottomhole zone of wells. The very first experience of hydraulic fracturing in the Kogalym region was carried out in 1989 at the Povkhovskoye field. A lot of time has passed since this moment, various technologies have been introduced hydraulic fracturing, and this process has become an integral part of the work of all fields of the enterprise. If earlier the main task of hydraulic fracturing was to restore the natural productivity of the reservoir, deteriorated during the drilling and operation of wells, now the priority is to increase oil recovery from reservoirs in fields that are at a late stage of development, both by involving in the development of poorly drained zones and intervals in objects with high degree development of reserves, as well as involvement in the development of low-permeability, highly dissected objects. The two most important areas of development in oil production over the past 15 years are hydraulic fracturing and drilling horizontal wells. This combination has very high potential. Horizontal wells can be drilled either perpendicularly or along the azimuth of fracture development. Almost no technology in oil and gas industry does not provide such high economic returns. Employees of the Tevlinsko-Russkinskoye field were convinced of this by testing the interval hydraulic fracturing method on well 1744G. Leading engineer of the enhanced oil recovery department, Yuri Miklin, told us about his successful experience.
In an era of high energy prices, mining companies strive to extract the maximum from their assets, extracting as much hydrocarbons as is economically justified, says Yuri, for this purpose they often involve in the development of extended reservoir intervals through horizontal wells. The results of traditional hydraulic fracturing in such wells may be unsatisfactory for economic and technological reasons. Interval or, as they also say, multi-interval method hydraulic fracturing, is capable of providing more efficient production of oil reserves by increasing the contact area of the fracture with the formation and creating highly conductive paths for oil movement. The deteriorated reservoir properties of formations are forcing mining companies to look for more and more economically profitable ways to construct a well for further stimulation of the formations of interest using the latest achievements of science and technology. Realizing this, companies are striving to reduce the time and, accordingly, the costs of additional hoisting operations and crew work overhaul wells using special equipment that becomes integral part wells.
One way out is to complete the well with a horizontal end with a liner with circulation valves on the assembly, which serve to inject a mixture of liquid and proppanite. This arrangement includes swellable packers designed to secure the liner and stabilize it in the open hole.
Process hydraulic fracturing formations is to create artificial and expand existing cracks in the rocks of the bottomhole zone when exposed to high blood pressure fluid injected into the well. This entire system of cracks connects the well with productive parts of the formation remote from the bottom. To prevent the cracks from closing, coarse sand is introduced into them and added to the fluid injected into the well. The length of cracks can reach several tens of meters.
Here it is necessary to take into account that the distance between the installation sites of circulation valves and, accordingly, the places where cracks initiate in a horizontal wellbore will affect the performance of each section, notes Yuri, that is, it is necessary to select the optimal distance between cracks based on the geometry of the designed cracks. We must protect ourselves as much as possible from the intersection of cracks in the productive formation, which can cause complications during hydraulic fracturing. Ideally, the maximum flow rate is possible when the distance between cracks is equal to the drainage radius. This condition is impossible to fulfill given the design of well 1744G, so the location of the fractures had to be chosen with the maximum possible distance from each other.
Taking into account the inclined occurrence of layers, horizontal wells the best way increase the contact area with the productive formation. Carrying out hydraulic fracturing using the “Zone Select” technology in the following way: produced first hydraulic fracturing furthest interval through an arrangement in which the circulation valve is already open. After that, a ball is launched from the surface into the tubing string (tubing) together with the displacement fluid, which, reaching the bottom of the well, first opens the second circulation valve to treat the next section, and then sits in a special seat, cutting off the treated interval. For two treatment intervals, one ball is used. In proportion to the increase in the number of processing intervals, the number of balls also increases. Moreover, each subsequent ball must be larger in diameter than the previous one. The balls are made of aluminum, and this is important. After stimulating the required number of intervals and injecting the calculated amount of a mixture of fluid and sand, the hydraulic fracturing fleet leaves the well. A fleet of coiled tubing (flexible tubing) arrives at the well, which carries out flushing, milling of balls and completion of the well, determining the inflow profile and production capabilities of the well. Development is carried out with nitrogen - this is the most promising direction for reducing pressure on the bottom of the well. The Kogalymneftegaz Chamber of Commerce and Industry used this technology to process two intervals of well 1744G of the Tevlinsko-Russkinskoye field. Compared to neighboring horizontal and directional wells, after hydraulic fracturing was carried out on them using standard technology, higher technological indicators were obtained at this well. The initial oil flow rate at well 1744G was about 140 tons per day.
Finally, I would like to note that it is the large-scale application hydraulic fracturing makes it possible to stop the decline in oil production at the fields of the Kogalymneftegaz Chamber of Commerce and Industry and increases the production of reserves from medium- and low-productivity reservoirs. The advantages of carrying out interval hydraulic fracturing in horizontal wells using the “Zone Select” technology are not only an increase in the effective contact area of the formation with the well draining the formation, but also overcoming damage to the bottomhole zone of the wellbore after drilling, as well as the introduction into development of poorly drained areas with low filtration and capacitance properties. This indicates that horizontal wells using interval hydraulic fracturing are more effective and cost-effective.
Russia expects sanctions pressure to increase. The UK and US are actively looking for new grounds for discrimination Russian business. However, the results of the latest wave of sanctions policy, which began in 2014, are far from clear-cut. Even independent studies show that the Russian fuel and energy complex did not suffer much from the restrictions; moreover, it was they that pushed the development of industry in Russia. According to industry experts, a possible increase anti-Russian sanctions will also not become critical for the Russian fuel and energy complex, but only if the government and energy companies mobilize forces in time to create a domestic engineering industry that produces mining equipment hard-to-recover reserves oil (TRIZ).
Russia must learn to mine TRIZ
The day before, the Energy Center of the SKOLKOVO Business School presented the results of its research “ Prospects for Russian oil production: life under sanctions“, where the impact of sanctions imposed in the USA and the EU on the Russian oil sector was analyzed, in particular on the commissioning of new traditional fields in Russia, the development of offshore projects, and the production of Bazhenov oil. The authors of the study also made a scenario forecast for Russian oil production until 2030.
The document notes that on the horizon until 2020, despite all the restrictions, Russia has the potential to further increase production volumes due to already prepared deposits. This short-term upside potential, however, may be limited by OPEC agreements. In the medium term until 2025, even if access to technology is severely limited and oil prices are low, production volumes will not suffer catastrophically. At the same time, the main reason for the decline in production during this period may be not so much the lack of access to Western technologies for the implementation of new projects, but rather the lack of technological capabilities to intensify production at existing fields.
This study showed that the most critical technology for maintaining Russian oil production is hydraulic fracturing, as it can maintain production at existing fields.
The use of multi-stage hydraulic fracturing (MSHF) promises increased production in promising unconventional fields.
The authors of the study emphasize that in the current conditions, it is the development of our own hydraulic fracturing and multistage fracturing technologies, the production of hydraulic fracturing and multistage fracturing fleets within the country and personnel training that should become a technological priority for industry companies and regulators. However, so far work in this direction is being carried out at a clearly insufficient pace. As the expert noted in her report Energy Center SKOLKOVO business school Ekaterina Grushevenko, in the period from 2015 to August 2017, not a single hydraulic fracturing fleet was produced. Rotary-steered systems, according to the website of the Scientific and Technical Center of Gazprom Neft PJSC, were at the testing stage at the end of 2016. The expert emphasized that already two-thirds oil reserves falls on TRIZ.
No production reduction is expected until 2020
Director of the Energy Center of the SKOLKOVO Business School Tatiana Mitrova in her speech at the presentation of this study, she noted that the first sanctions against Russia and Russian energy companies were introduced in 2014, but no specific studies have been published on their impact on the oil industry.
“We didn’t know what result we would get. The first hypothesis assumed that the consequences would be very severe,” said Mitrova. However, the results showed a slightly different picture of the impact of sanctions.
“Currently, no serious consequences of sanctions are felt in the operating activities of companies. Indeed, production has been growing in recent years, despite low prices and sanctions. The oil industry reported success. But the positive current situation should not be misleading; an analysis of the set of sanctions itself indicates their very broad interpretation, and this is the main threat of sanctions pressure,” the expert pointed out.
According to her, until 2020, according to the modeling results, no reduction in production is expected, since the main projects have already been financed.
“Starting from 2020, negative trends will become more and more noticeable and could lead to a decrease in oil production in Russia by 5% by 2025 and by 10% by 2030 from current production levels. A reduction in production on such a scale, of course, is not catastrophic for the Russian economy, but nevertheless quite sensitive,” Mitrova said.
She emphasized that the sanctions are Long story and so that the Russian oil industry has adapted to them, additional efforts by the state and companies are needed to develop their own technologies and produce the necessary equipment.
“There is a huge part of oil production that directly depends on hydraulic fracturing technology. It is the presence of this equipment that has greatest influence on oil production volumes in the country. But the development and implementation of production of this technology in to a greater extent task Russian government and industry,” explained the director of the Energy Center.
New industry required
Head of the “Gas and Arctic” department at the SKOLKOVO business school Roman Samsonov in his speech he noted that, according to his personal observations, in Russia only against the backdrop of sanctions can one observe progress in the development and production of its own high-tech equipment.
“The situation with the production of high-tech equipment is complex, but you can learn to manage it. Actually we're talking about on the creation of an entire multifunctional sub-industry of oil and gas engineering,” Samsonov noted.
According to the participants in the study “Prospects for Russian oil production: life under sanctions,” such a large-scale task to create a new sub-industry of heavy engineering in Soviet times was solved only thanks to government directives. In modern conditions market economy, in which the Russian Federation is currently developing, the mechanisms for implementing this task have not yet been worked out.
However, this is only in Russia. If you look at the experience Western countries who successfully overcome all difficulties to extract TRIZ, it becomes clear that such a method has long been found. This is most clearly seen in the example of the US shale industry, which was actively credited even during the period low prices, which helped her survive. It is obvious that such a tolerant attitude of banks towards this sector of oil production could not do without state participation. Now grateful shale producers are helping the US authorities restrain OPEC and other oil producers, actively influencing the global oil and gas market.
Ekaterina Deinego
Types of hydraulic fracturing
Currently, in world oil production practice, three main types of hydraulic fracturing are used: conventional hydraulic fracturing (HF), deep-penetrating hydraulic fracturing (GHF), and massive hydraulic fracturing (MSHF). Each of these types has its own area of application.
Hydraulic fracturing is used as a means of increasing the permeability of the near-wellbore formation zone. It is used, as a rule, in individual wells with a contaminated bottom-hole zone in order to restore their natural productivity, characterized by the use of a small amount of fixing material (5-10 tons).
Hydraulic fracturing is one of the most effective methods for increasing the productivity of wells draining low-permeability formations (with permeability less than 0.05 µm 2). This process is characterized by the use of large quantities of fastening material - 10-50 tons and fracturing fluids - 150-200 m3. In this case, cracks or a system of cracks of considerable length (50-100 or more meters) are created, covering not only the bottomhole zone, but also a significant part of the layer. This is the main difference between GGRP and conventional hydraulic fracturing. The scope of application of hydraulic fracturing is low-permeability reservoirs or its individual sections with the aim, in particular, of achieving profitability in the development of such fields. Hydraulic fracturing technology is intended to impact undepleted (undeveloped) oil deposits, where productive formations are represented by terrigenous (sandy) reservoirs.
Multi-stage hydraulic fracturing is massive hydraulic fracturing, which is used in practice in low-permeability reservoirs gas fields. The main feature of this process is the creation of artificial cracks of a very large extent. Large quantities of fixing material are used for these purposes.
New hydraulic fracturing technologies
Significant expansion of the scope of hydraulic fracturing and an increase in the number of operations during last decade associated with the intensive development of processing technologies. To new ones effective methods should include the technology of proppant deposition at the end of the fracture or tip shielding of the fracture (TSO), which allows you to purposefully increase its width, stopping the growth in length, and thereby significantly increase conductivity (the product of permeability and width). To reduce the risk of a crack entering water or gas-bearing horizons, as well as to intensify the development of reserves of low-permeability layers, selective hydraulic fracturing technology is used. New materials for hydraulic fracturing are constantly being created. In order to prevent the removal of proppant from the fracture, the PropNET technology was created, which involves injecting into the formation simultaneously with the proppant a special flexible glass fiber, which, by filling the gaps between the proppant particles, ensures maximum stability of the proppant pack. To reduce the degree of residual contamination of the fracture, low-polymer fracturing fluids LowGuar and a system of additives to the CleanFLOW destructor have been developed. The non-polluting ClearFrac liquid is used, which does not require a destructor.
Improving information base carrying out hydraulic fracturing. The main sources of information are geological, geophysical and petrophysical studies, laboratory core analysis, and a field experiment consisting of micro- and mini-hydraulic fracturing before the main hydraulic fracturing. In this way, the stress distribution in the formation is determined, the effective fracture pressure and fracture closure pressure are determined, a fracture development model is selected, and its geometric dimensions are calculated. Special instruments allow you to determine the height and azimuth of the crack. Using special programs, taking into account the hydraulic fracturing objectives, the “design” of the fracture is carried out.
The use of new technologies makes it possible to select the fracturing fluid and proppant that best suit specific conditions, and control the opening and propagation of the fracture, the transport of proppant in suspension along the entire fracture, and the successful completion of the operation. In recent years, technology has been developed for an integrated approach to hydraulic fracturing design as an element of the development system. This approach is based on taking into account many factors, including the conductivity and energy potential of the formation, the placement system of production and injection wells, fracture mechanics, characteristics of the fracturing fluid and proppant, technological and economic limitations.