Equipment for horizontal drilling of oil wells. Technology of drilling horizontal wells with drilling rigs. Horizontal drilling technology

An inclined well with a bore curvature angle of 80 0 and higher is called horizontal (Figure 62). The horizontal part of the trunk opens the productive formation along and remains uncased. The length of the horizontal section is equal to one slot.

Figure 62. Horizontal well

Based on the radius of curvature of the trunks, there are 3 types of horizontal well profiles:

• large radius (more than 300m);
• average radius (100-300m);
• small radius (10-60m).

Horizontal ones with a large radius can be implemented using the cluster drilling method with large waste and with a horizontal section length of 1000 m or more. In this case, standard equipment and directional drilling technology are used, which makes it possible to obtain a curvature intensity of up to 2-2.5 0 /10 m.

Horizontal wells with a medium radius are used when drilling both single wells and to restore the productivity of production wells. In this case, the maximum intensity is 3-8 degrees per 10m of penetration with a horizontal section length of 450-900m. Wells drilled along an average radius are the most economical, since they have a shorter barrel length (compared to the length of a well with a large radius), ensuring a more accurate hit at a given point on the surface of the productive formation, which is very important in the presence of thin oil and gas formations .

Horizontal wells with a small radius are successfully used when drilling fields that are at a late stage of production, as well as when drilling second trunks from previously drilled wells. To do this, cut out a window, or use a milling section of the casing of 8-10 m. Under these conditions, the pumping equipment is placed in the main shaft, and it is desirable that the value of the zenith angle at the site of its installation and above does not exceed 20 0. The intensity of curvature of such trunks can be 1-20 per 1 m with radii of 10-30 m, and the length of the horizontal section can be up to 90-150 m.

If drilling along a large radius does not require special equipment, then drilling shafts with a medium and short radius can only be carried out using special drill pipes and shortened and short downhole motors, which make it possible to bend shafts with a radius of curvature of 25-50 m (instead of 250 m and more). Designing a horizontal well begins with determining the length, shape and direction of the horizontal section. These parameters depend on the degree of heterogeneity of the productive formation, its thickness, lithology, hardness and stability, the angle of incidence of the formation, i.e. on the geological characteristics of the formation.

In the field of extraction of valuable energy resources, drilling of horizontal oil wells occupies an important place: with the help of this technology, it becomes possible to extract oil from hard-to-reach places, as well as to develop difficult rock sections. The horizontal well created during the drilling process has a certain angle of deviation from the axis of the vertical well, making it possible to pump out oil in the fastest and most productive way.

Work on drilling wells should take place only after the preparatory stage. This includes studying the soil at the drilling site, obtaining permits, which is legal confirmation of the legality of oil production in a given location.

Well drilling methods

Inclined wells in general and horizontal wells in particular can be drilled in several ways.

The following drilling technologies are considered the main methods:

• Directed work.
• Service installation drilling.
• Directed process of intra-fault type.

It is worth noting that the second method is usually carried out in conjunction with laying communications underground, and the third method is more often used in a coal seam, since in this case gas removal may be required.

Technological features of drilling

Due to the decline in the efficiency of old wells, many companies are increasing production through intensive development of existing and discovered oil deposits. Horizontal directional drilling of horizontal wells is a very productive way to increase raw material production. Its essence is to expand the area of ​​product introduction into the wellbore. During horizontal drilling, wells with horizontal sections are formed, which can be continued during inclined drilling.

Drilling horizontal wells has a number of features that balance the impact of this method on the environment

• Trenchless construction is one of the technical methods that allows you to work near a high-voltage power line, in a residential area or near a road junction.
• To reduce time costs when drilling horizontal wells, it is optimal to use complex equipment, since the volume of labor is small, as is the number of equipment involved in the work. In addition, in this case there is no need to take action to lower the groundwater level if it is too high.
• The financial issue also plays an important role: a reduction in the work process leads to a reduction in the estimate that is included when planning a well. The use of high-tech devices helps to minimize costs.
• From a social and environmental point of view, such mineral developments do not cause harm or inconvenience to people who permanently live in the oil production area.

Application of horizontal drilling method

This method not only helps to increase the amount of oil produced from already exploited fields. It also makes it possible to successfully develop areas that are considered unproductive and unprofitable when drilling a conventional well.

This method brings success in a number of cases:

• Malfunctions of drilling equipment.
• An oil field located in a part that is difficult to access by conventional operating technology.
• Extraction of oil lying at the bottom of a large body of water (ocean or sea).

Drill failures can occur due to the occurrence of particularly hard formations on the way to the deposit. Also, the drill can become jammed at the mining site, and it can no longer be removed from the rock. To continue development and at the same time bypass a layer that is too strong, you can drill a horizontal well at an angle or in parallel.

In some cases, standard well drilling is replaced by horizontal laying technology due to the complex terrain and close location to a reservoir. In addition, this method makes it possible to quickly and easily reach the desired rock layer and select the most comfortable place for oil extraction.

If the oil is located on the ocean or seabed, horizontal drilling will require minimal costs, while standard technology requires the installation of an offshore platform, which will be very expensive. In the same way, underground oil storage facilities can be constructed.

Characteristic factors in the drilling process

Horizontal directional drilling for oil production is accompanied by the use of innovative technologies that make it possible to construct a well with a large angle of deviation from the vertical direction. As a rule, the layers that contain oil have a horizontal structure, and this technological feature makes the extraction of such oil possible. Horizontal wells, unlike standard ones, are distinguished by higher productivity rates when comparing drilling results in the same area.

The pass is made in a predetermined mode in the required layers. The work must be carried out in compliance with the operating conditions of the installation, which destroys the bottom of the well.

The effectiveness of such destruction is assessed by the following indicators:

• The degree of load on the bit, which has a direct relationship with the axial pressure.
• The number of revolutions during operation of the device.
• The quality of clay material in each layer and its percentage.
• Method of using the device.

By taking into account all the features that accompany drilling a horizontal well, you can determine which method will be optimal. Operating conditions generally correlate with drilling methods, and if the technology is applied ideally, the greatest increase in productivity can be achieved during horizontal well drilling.

The drilling site may be located at some distance from the layer in which the oil lies, and production will have a positive result. At the same time, the standard method can greatly damage the environment from an ecological point of view, and therefore horizontal wells not only have high productivity, but also do not cause damage to nature and humans.

The key benefit of horizontal directional drilling is maintaining the balance of ecosystems and not harming landscapes that are not directly impacted. The negative impact on human living conditions also tends to be minimal, so oil production can also be carried out near settlements and cities.

Preparation for the process

The process of creating a horizontal well for the extraction of an oil or gas product can be carried out using a deep drilling method and the use of appropriate equipment. In this case, first, a geological and technical work order is drawn up and a technical map is created. Technical regulations control the stages of implementation.

The key stages of drilling horizontal wells are in the following order:

1. Assembling equipment for work.
2. Operations for lowering or raising automatic equipment.
3. Approximate drilling work.
4. Creating a solution, adjusting its density and severity, as well as processing with special substances.
5. Sealing the wellhead.
6. Jamming works.
7. Preparation of studies of finished shafts based on geophysical parameters.
8. Preparing the shaft for lowering the rock tester.
9. Exploding projectiles to select roll.
10. Development of a ready-to-receive well.
11. Delivery of drilling complexes.

Each action of the preparatory stage requires regular testing of the well solution and maintaining its properties at the desired level, while its analyzes are periodically updated. Shaft mouths must be equipped with equipment that prevents the release of oil products, as this will minimize the risk of operational emergencies.

The technical condition of devices used in operation must be checked in a timely manner; To check the serviceability of equipment, it is necessary to use control and measuring devices, the operating condition of which must also be monitored, automation and safety elements.

Any complications that arise when drilling a horizontal well must be eliminated. After the preparatory stage ends, it is necessary to test the rock layers. Each drilling process requires regular preventive inspection of the equipment used, which is carried out before and after work.

Features of control in horizontal drilling of wells

An important aspect of the work is the control of equipment during the drilling process, since the drill itself is located at a distance. Horizontal technology requires careful monitoring to avoid disastrous consequences. The work uses a location system, which should implement the process control function. The system is a special probe located in the drill head. The synchronization of the probe's actions is carried out using special equipment, and the operator regulates these actions while on the surface of the earth.

Among other actions, the probe will note at what angle horizontal wells are being drilled at the moment, and the information received is sent to the device with which the operator controls the system. The specialist also monitors the number of revolutions of the device and the temperature of the drill head. The more quickly the information arrives at the control panel, the higher the likelihood that dangerous situations will be anticipated on time.

The horizontal drilling process is carried out using complex installations, and they usually include the following structural parts:

• Frame.
• Carriage.
• Body part.
• Running installation system (it can be on wheels or tracks).
• Hydraulic installation.
• Power station.
• Remote Control.
• Diesel engine.
• Rod feeding system.

The classification of drilling equipment may depend on the drawing limit, and this indicator is measured in tons. Also important is the diameter of the expansion, as well as the length of the barrel: these values ​​​​are measured in maximum limits. Secondary data serves to more fully characterize the qualities of the equipment used in the work: this is the bending radius of the rod columns. This indicator allows you to find out the force of trajectory change that may be required during initial drilling, as well as the cost of solution to form a stable horizontal well. All these indicators allow you to carry out work most efficiently and safely.

Drilling must be used in the construction of a large number of structures; it is used in the construction of water supply systems and for the extraction of minerals. The well is a cylindrical mine working.

One type of well is horizontal well; they are necessary in oil production and in cases where the well needs to be laid in a populated area, for example, under a road.

The length of such wells is much greater than their width; its upper part is called the mouth, and the lower part is called the bottom. The trunk of the structure is the walls. Drilling horizontal wells is environmentally friendly and does not cause serious harm to the environment.

Usually this design has a right angle of deflection, but since there are no ideally straight lines, and cannot be, it is necessary to drill the shafts along a trajectory close to the optimal one.

The advantage of these wells is that they produce much more oil than vertical wells. This is more expensive, but productive drilling. A horizontal well is usually a production well, but can be an injection well.

Drilling horizontal wells

When drilling a horizontal well, it is important to correctly determine the required number of columns and the installation depth of the “shoes”; for this you need to know the exact number of zones where it is impossible to drill a well due to rock instability.

Before opening productive and productive horizons, provide for the descent of one column so that there is no rupture of the rocks.

• The difference between the diameter of columns and wells must be selected taking into account the values ​​​​determined by drilling practice, so that the running of the column is easy and durable and high-quality cementing is ensured. When a decision is made to drill a well, it is important to know these nuances.
• Before drilling begins, soil samples must be analyzed to determine whether drilling is possible in a given location. The depth of the pipes depends on the properties of the soil. Based on the analysis, it is necessary to obtain all the necessary permits for work.
• Next you need to make a pilot well. A pilot well is a typical test hole. Drilling it requires a small drill head connected to a special rod. With its help, you can control and adjust the laying of the trench.
• A rod is a long pipe, one section of which can reach 3 m. For such drilling, only diamond-coated heads are required.
• A special transmitter must be built into the head itself, the signals of which would be sent to the receiving device; if the equipment goes astray, this will be reflected on the display and all errors can be easily eliminated.

To expand the well, you need to use a special expander, it is pulled in the opposite direction, it is necessary to cut off excess layers of soil. In order for pipes to be easily inserted into the well, its diameter must be 40% greater than the width of the pipe.

After the well is drilled, pipes need to be laid into it. The expander is pulled from the end of the well, and a pipe grip is attached to it.

Proper well construction is very important; they usually use polymer pipes, they are durable and maintain physical and chemical stability.

If you have drilled a well to lay communications through which hot liquid or chemically aggressive compounds will flow, it is better to use metal pipes, since plastic pipes will begin to crumble, deteriorate and will not withstand the load.

After completing the work, you need to prepare all the necessary documentation and submit the object for acceptance.

This work can only be performed by qualified engineers who can technically justify all the measures taken; communications must be accurately tied to the area, exactly as indicated in the documents.

From an economic point of view, horizontal wells are very profitable; drilling them does not require a lot of personnel, so you can save on wages. Often drilling can be carried out by a team of 3 people.

This method will allow you to lay a pipe under a busy highway literally within a few hours, without destroying its coating, and will also reduce the cost of equipment and tools, although there are, of course, other methods of drilling wells.

If you take care of the consent documentation in advance, you can obtain information in advance about the cables existing underground, that is, there will be no need to repair damaged communications.

To drill such wells, you need special equipment with high strength characteristics; there is both Russian and foreign such equipment on the market.

As for durability, Russian equipment is superior to foreign analogues, and in addition, it is cheaper. It is perfectly adapted to Russian drilling conditions. It is easier to purchase spare parts for it and will provide very serious savings.

A decline in oil production growth rates is observed throughout the world. Mining companies, trying not to lose precious barrels of black gold, are improving methods for extracting hydrocarbons from open deposits. One of the advanced methods is drilling horizontal wells in productive formations, which we will talk about in this article.

Directional drilling of wells on pads preceded the improvement of methods for orienting the drilling tool in the well. Telemetric control using cable has been replaced by innovative digital technologies that allow real-time monitoring and control of the specified azimuth and zenith angle of the well. It is now possible to drill hydrocarbon reservoirs horizontally. It is estimated that the cost of drilling horizontal wells exceeds the cost of vertical wells by 2 times, and sometimes more. But the productivity of horizontal wells is 3 or more times higher than that of vertical wells. It is obvious that the costs are recouped already in the first years of production.

Horizontal drilling technology

Before constructing a well, design documentation is developed, which includes the geological, technical and economic parts of the project. The main document for drilling a well is the GTN (geological and technical work order).

Drilling a horizontal well is carried out in several stages:

• drilling a vertical shaft with casing (conductor)
• drilling with a set of curvature (zenith angle) and direction (azimuth), securing the shaft with a technical column
• drilling with a set of curvature, stabilizing the angle, entering the productive formation at a low angle, drilling a horizontal section, running a production string or liner.

The most difficult stage is drilling with a set of curvatures. We have to work using telemetry and special deflectors. Information about the position of the drill string is displayed on the screen, where the operator sees the actual position of the string in the well, compares it with the design one, and transmits commands to the driller, correcting the direction.

When drilling a technical column, it is important to obtain the required zenith angle and azimuth. After attaching the technical casing string, the critical section of continuing the set of curvature and stabilizing the angle begins, so that the wellbore before entering the productive formation has an angle close to 80 degrees, and moves horizontally in the formation.

Modern drilling methods use downhole motors and bits that can change the direction of drilling using drilling fluid. In such a case, the engineer can orient the drill bit by computer program using positioning signals to determine the location of the bit relative to the oil or gas formation.

The length of the horizontal sections is constantly growing and the deviation from the vertical shaft by 1000 m has long been closed, the record is more than 11,000 m.

The advantage of horizontal drilling is obvious: increased oil recovery. Even in long-explored and exploited areas, the method of lateral perforation of vertical columns is used, followed by drilling horizontal branches in the productive formation.

Horizontal drilling is performed with special, sometimes imported, expensive equipment. This requires increased technological discipline, requiring high performance skills. This is more of a complication than a drawback. That is why many oil companies have their own educational centers, where their specialists are trained in new technologies. With highly qualified specialists, of course, there is no such problem. For example, in the Naftagaz company, about 70% of wells are drilled using the horizontal method.

The time of large discoveries of hydrocarbon deposits is ending; ahead is the prospect of developing deposits using horizontal drilling and subsequent hydraulic fracturing (hydraulic fracturing).

Horizontal wells: from bold experiment to traditional technology

Horizontal drilling is gaining momentum. More and more wells are being drilled horizontally, or sidetracks are being cut from vertical wells. Directional wells are used in the development of offshore fields from platforms or from the shore, in regions with complex geological conditions that require long horizontal well bores. Such wells have a complex spatial architecture, which determines the need to use innovative technologies, equipment and qualified personnel. And although this requires large financial and material costs, in the end it significantly increases the drainage area of ​​the productive formation, which increases flow rates, and therefore the profits of companies. The editorial round table, conducted by express survey, was devoted to this topical issue.

The horizontal drilling are gaining momentum. More wells drilled with horizontal bottom or from vertical wells cut sidetracks. Directional inclined wells used in the development of offshore fields or platforms with the shore, in regions with complex geological conditions, requiring extended along the length of the trunks horizontal wells. These wells have a complex spatial architecture that determines the necessity of application of innovative technologies, equipment and qualified personnel. And although it requires significant financial, material costs, and, ultimately, significantly increases the drainage area of ​​the reservoir, which increases flow rates and, therefore, the profits of companies. “Round table” revision carried out by the method of an opinion poll devoted to this actual issue.

If in the 70s and 80s horizontal wells were a rare episode, a bold experiment, a demonstration of the capabilities of equipment and technology, now it is an industrial necessity and a common practice of drilling wells. Statistics show this. Thus, based on the results of the first quarter of 2017, it is clear that the majority of oil companies are paying more and more attention to horizontal drilling, the volume of which takes up more than a third of the total drilling footage. For example, in the LUKOIL company, horizontal wells account for 35% of the total drilling volume, Rosneft - 36.9%, Gazprom Neft - 71%, Bashneft - 76%, RussNeft - 89.7% of the total volume of penetration!

KULCHITSKY Valery Vladimirovich,

Russian State University of Oil and Gas (NRU) named after I.M. Gubkina

Doctor of Technical Sciences, Professor. Executive Director of the Central Board of the Scientific and Technical Society of Oil and Gas Workers named after Academician I.M. Gubkina, Deputy Head of the Department of Oil and Gas Well Drilling, Director of the NIIBT Russian State University of Oil and Gas named after. THEM. Gubkina.
An authoritative specialist in Russia in the field of geosteering and intelligent well systems. Expert on industrial safety in the oil and gas industry of the Federal Service for Environmental, Technological and Nuclear Supervision, member of the European Association of Geophysicists and Engineers EAGO. Awarded the medal “To the Author of a Scientific Discovery” named after. P.L. Kapitsa (2003) for the development of the theoretical foundations for creating smart wells.

There is a need to discuss with experts the current problems of constructing directional, horizontal and multilateral wells.
We present the opinion of professionals on this very relevant topic.
There are many components to successful drilling of horizontal wells, neglecting any of which can complicate or ruin the process. But still, the most important thing in this technology is the geonavigation, logging and telemetry systems. And that’s why we started our survey with a question about the quality of the equipment used.

V.V. KULCHITSKY:

“The development of the first domestic cableless downhole telemetry systems: ZIS-4 as an analogue of the MWD system and “Zaboi” as an analogue of the LWD system (developed by VNIIGIS, Oktyabrsky) was financed by the Ministry of Geology, but were never in demand by either geologists or oil workers - drillers. After unsuccessful state tests of the ZIS-4 in 1984 at the Samotlor field in the drilling crew of Hero of Socialist Labor Anatoly Dmitrievich Shakshin, the oil workers abandoned the “electronic supervisor” of directional wells, subjectively controlled by the “tip of a pencil.”

– How does the quality of equipment affect the results of horizontal drilling?
V.V. KULCHITSKY, Russian State University of Oil and Gas (NRU) named after I.M. Gubkina. As a federal expert at the Ministry of Education and Science, I quite often have to investigate incidents that occurred during the geosteering of wells with complex spatial architecture. I can conclude that the underfunding of domestic geonavigation equipment is still sticking out, especially at the stage of development to industrial designs and implementation in the 80–90s. last century. A large share of unproductive time and accidents occurs in domestic television systems.

The development of the first domestic cableless downhole telemetry systems: ZIS-4 as an analogue of the MWD system and “Zaboi” as an analogue of the LWD system (developed by VNIIGIS, Oktyabrsky) was financed by the Ministry of Geology, but were never in demand by either geologists or oil workers - drillers. After unsuccessful state tests of the ZIS-4 in 1984 at the Samotlor field in the drilling crew of Hero of Socialist Labor Anatoly Dmitrievich Shakshin, the oil workers abandoned the “electronic supervisor of directional wells, subjectively controlled with the tip of a pencil.” This is written about in the book: Kulchitsky V.V. Geocosmos (M.: ITSRGUNG, 2013, 146 p.).

S.V. KOLBIN, OJSC "Surgutneftegas". Equipment quality is one of the key issues in horizontal sidetrack drilling. Failure of any element of the BHA leads to additional costs. We have been working together with manufacturers for more than one year to increase the durability of bits, increase the time between overhauls of the PDM and the time between failures of telemetry systems in order to achieve a time-balanced operation of the “triad” (bit + PDM + telesystem), striving to ensure that there are no unplanned SPO due to failures. Almost all equipment is subjected to testing, pressure testing, and run-in before being sent to teams.
I.A. LYAGOV, LLC Perfobur. Quality is a set of basic consumer properties of any technical product and is determined by a fairly extensive range of indicators from various groups: purpose, reliability, manufacturability, ergonomics, etc.

Therefore, the quality of the equipment used for the construction of horizontal wells directly affects the results of the work.
For example, in the company Perfobur LLC, all components are tested on a stand where drilling modes are tested with various bits and downhole motors, cutters are selected for casing columns of various strength categories, and the trajectory of drilled sand-concrete channel blocks is recorded.

KOLBIN Sergey Viktorovich,

OJSC "Surgutneftegas"

Sergey Viktorovich works as the head of the Department for Overhaul of Wells and Enhanced Oil Recovery of the Open Joint Stock Company "Surgutneftegaz".

M.V. RAKITIN, LLC "LUKOIL - Nizhnevolzhskneft". Taking into account the specifics of our company, I would probably correct the questions a little. After all, we work in offshore fields; drilling horizontal wells at sea is fundamentally different from drilling sidetracks on land. Therefore, it is logical to add the question: “Why is offshore drilling fundamentally different from onshore drilling?”
I will answer: the main reasons for this:

S.V. KOLBIN:

“Equipment quality is one of the key issues in horizontal sidetrack drilling. Failure of any element of the BHA leads to additional costs.”

– increased requirements for the safety of drilling, operation and abandonment of wells at sea;
– very high financial costs require maximum reduction of construction time, which is impossible without the use of reliable and world-class high-tech equipment;

– there are quite a lot of exploration (vertical) wells on land, so the geological and operational model is very reliable. There are few exploration wells at sea, so when constructing production wells, the problem of additional exploration of the field with horizontal wells is additionally solved.
We are drilling in the North of the Caspian Sea, so the answers to other questions will be related to offshore drilling.
Geosteering at our fields is carried out remotely by a small team, which includes: a geonavigator, a GIS interpreter (petrophysicist), a geomechanicist and the Customer's supervisory service. For geosteering, seismic data, geological survey data and GIS drilling (MWD&LWD) data received in real time during drilling are used.

A.V. MIKHAILOV:

“It is thanks to geomechanical modeling that we can select the optimal density and formulation of the drilling fluid. Also, with the help of specialists from the NNB Technical Solutions Center, together with mud service engineers, all necessary hydraulic calculations are prepared taking into account the BHA and drilling tools - to understand the expected equivalent circulation density (ECD), the effect of swabbing and pistoning, all risks are considered both during drilling, and during hoisting operations.”

GIS drilling equipment (MWD&LWD) plays a very important role in offshore drilling. In addition to obtaining standard information to determine lithology, porosity and the nature of saturation, we hope for additional data, so at sea we are increasingly beginning to use special GIS drilling methods (MWD&LWD): HDD with sampling, NMR.
A.V. MIKHAILOV, Halliburton company. Drilling wells, in particular horizontal ones, is always associated with large overloads and vibration effects due to imperfections in the quality of the borehole, large spatial intensities, and differences in the diameters of downhole equipment and drilling tools. It is also necessary to take into account the fact of the influence of drilling fluid, high pressure and temperature. Of course, high demands have always been placed on the quality of HDD and logging-while-drilling (LWD) equipment. Since any failure of this equipment always entails unplanned BHA changes and production-recovery operations, which generally affects the well construction period, thereby increasing the costs of operating companies.
Any NNB equipment must undergo a certain cycle of inspections and tests at the development stage. It is subjected to all possible mechanical tests, such as bending, torsion; is tested on a vibration and hydraulic stand. After which he has the right to undergo field tests. Only after field testing does the equipment receive a certificate or passport confirming its performance in difficult mining and geological conditions.

– What manufacturers’ geonavigation systems do you use? Why do they attract you: price, ease of operation and maintenance, reliability, working life?
V.V. KULCHITSKY. The era of development of Western Siberia by high-tech domestic geosteering of oil wells of complex spatial architecture began on July 15, 1990, when a well with a horizontal trunk length of 209 m was drilled in the Samotlor field in 30 days and put into operation in the corridor of the AB1+2 formation ("grouse") of the hard-to-recover oil. The flow rate was 2 - 7 times higher than the neighboring wells with vertical opening of the formation!!!
A little theory to understand the complexity of the technology.
Geosteering, an integral and defining part of geonautics, is a scientific direction within which technological, hardware and software problems of controlling the wellbore trajectory are set and solved in conjunction with the study of the near-wellbore space and the impact on it during the drilling process. This is written about in the book: Kulchitsky V.V. Geosteering technologies for drilling directional and horizontal wells (M.: VNIIOENG, 2000. 351 p.).
Geosteering is a high-tech segment of shale oil development. To develop oil deposits with shafts of significant length and coverage area of ​​the oil reservoir, reliable intelligent and cybernated BHAs with a service life of up to 1000 hours are required, providing one flight of bits up to 10,000 m. To develop multifunctional intelligent downhole equipment based on a drilling tool with a built-in power cable and a valve electric drill NOVOBUR LLC (Perm) has started to revolutionize the technique and technology of drilling horizontal and multilateral wells - the basis of the rapidly developing geosteering.

LYAGOV Ilya Alexandrovich,

Perfobur LLC

Candidate of Technical Sciences, specializing in “Drilling and Well Development Technology.”
He completed his postgraduate studies at the National Mineral Resources University “Mining” (St. Petersburg).
Graduate of the Department of Oil and Gas Field Equipment of the Ufa State Petroleum Technical University. Studied at the Freiberg Mining Academy (Germany).
Specialist in the field of well injection, secondary opening of reservoir zones. Currently he holds the position of chief engineer at Perfobur LLC, a company engaged in the development of new radial drilling technology.

Shale oil is oil that is extracted from shale deposits formed from plant and animal residues found in a solid or liquid state in low-permeability rocks (Tight Oil).
Oil source rocks are sedimentary rocks, impermeable in real time, capable, under certain geological conditions and time (millions of years), of releasing free hydrocarbons formed in the process of dia- and catagenetic transformations of the dispersed organic matter contained in them, when generally accepted technologies give an oil recovery factor (ORF) – from 0 to 1 – 3%.
Each shale formation corresponds to a certain maturity of organic matter (OM) - (certain thermobaric conditions, being in a certain stage of mesocatagenesis - “oil and gas generation window”). It is necessary to create conditions in the mountainous space under which mobile hydrocarbons are generated from the kerogen of the oil source rock. Identification of the patterns of sedimentation of deposits of the Bazhenov Formation (BF) determines the geosteering strategy of wells and the spatial architecture of multilateral directional and horizontal wells. The dependence of the filtration-capacitive properties of rocks on the textural and structural features formed during the process of sedimentation and post-sedimentary transformations of the original rocks determines the tactics of geosteering of multilateral wells.

The example of a georeactor shows the trend in the development of geosteering in the world in general and in Russia in particular. This is a high-tech innovative development of underground space (geocosmos) using wells of considerable length and coverage area. The length of the wellbore, and not the depth, has become a parameter for world records in the development of subsoil! Subsoil - that is, geocosmos, along with underwater, air and airless, is the fourth type of space - underground, in which human activity is increasingly taking place, which undoubtedly leads to changes in the structures of production and consumption. The significant resistance of rocks to the movement of machines and mechanisms, the presence of high pressures and temperatures impose specific requirements on technical means and technologies capable of ensuring active human activity in the underground space.
S.V. KOLBIN. We work with telemetry systems of various sizes with hydraulic, cable and electromagnetic communication channels, as well as with a combination of the last two, depending on the tasks being solved, for example: what kind of flushing liquid is used, a biopolymer solution, or, if the work is carried out at depression, nitrogen-aerated oil . The combined data transmission channel is unique, developed by the manufacturer according to our technical specifications.
I.A. Lyagov. In our Technical System (TS) “Perfobur” we plan to use an autonomous (and in the future - equipped with an on-line communication channel) domestically produced television system produced by the company SKB “PN” JSC.

EDITOR:

“Due to the fact that the total well stock in Russia is entering a period of declining production, the need will push for large-scale development of the Bazhenov Formation, the territory of which extends in Western Siberia over an area of ​​​​about 1 million km 2 with huge reserves – up to 140 billion tons of oil” .

Today we are recording the trajectory of channels drilled on our equipment using the Perfobur TS. This allows you to repeatedly enter an already drilled channel for research, intensification and, in the future, for its overhaul.
JSC SKB PN (St. Petersburg) interested us because the specialists of this supplier were the first to respond to the proposal to develop a small-sized autonomous fluxgate inclinometer (36 mm in diameter and less than a meter long - in a sealed housing), capable of operating in channels with radius of curvature less than 7 meters.
M.V. RAKITIN. Our offshore drilling practice uses GIS drilling equipment (MWD&LWD) from Schlumberger.
A.V. MIKHAILOV. Sperry Drilling Services, as the directional drilling department of the Halliburton service company, has its own geonavigation systems. In particular, we have a high-tech ADR device - an azimuthal deep resistivity sensor. It is an excellent solution for optimizing the well path, maximizing production and extending the life of the well.
The ADR combines a deep penetration directional drilling sensor with a traditional multi-frequency compensated resistivity sensor. Deep measurements (up to 6 meters), high-resolution images allow you to receive early warnings from approaching the boundaries of the formation to exiting the productive zone, allowing you to maintain the position of the well in the most productive part of the formation.
Like all Halliburton tools, the ADR has great reliability and a special design designed for drilling horizontal wells of varying complexity.

– What bottom drill string layouts do you use when constructing horizontal wells and sidetracking?
S.V. KOLBIN. In addition to the telesystems mentioned above, when drilling sidetracks, we use PDM (in dimensions from 73 to 127 mm) and bits with a diameter from 85 to 142.9 mm, both domestic and foreign manufacturers. The use of RSS is not widespread, since sidetracks are carried out mainly in drilled, “old” fields.

I.A. LYAGOV:

“Currently in Russia there are technologies for the construction of multilateral wells that can compete with the Big Four companies.

I.A. Lyagov. As part of the bottom hole assembly of the Perfobur TS, we use special small-sized screw downhole motors with one or two skew angles, an axial load control device capable of operating in both damper and ascillator modes, small-diameter PDC bits (58 - 60 mm ), as well as centralizers, the installation locations and diameters of which are selected depending on the required channel trajectory parameters. A stand-alone inclinometer may be included in the arrangement.
M.V. RAKITIN. Schlumberger PDM, bits and RSS are used. GIS drilling equipment modules (MWD&LWD) are included in the BHA assembly and are used at all stages of production well construction.

A.V. MIKHAILOV. Specialists from the Center for Directional Drilling Technical Solutions (Solution Engineering) of our company design and select the BHA individually for each horizontal well. This is done in order to reduce the cost of the layout as much as possible, but at the same time fully solve the tasks set by the Customer. When designing a BHA design, such basic aspects as the maximum spatial intensity of the well, its deviation from the wellhead, the length of the horizontal section, possible tortuosity and cavernousness are taken into account. At the first stage, calculations of the mechanical loads on the BHA and the drilling tool are made to understand the possibility of the formation of curvature in the string, which gives an understanding of the possibility of directional drilling. Based on this analysis, a conclusion is made about the feasibility of using RSS in the BHA.

RAKITIN Mikhail Vladislavovich,

LLC "LUKOIL-Nizhnevolzhskneft"

Mikhail Vladislavovich has been working in logging for more than 35 years. Graduate of Moscow State University. M.V. Lomonosov. Has experience working as a field engineer on Russian and foreign equipment. Processed and interpreted GIS, geological logging and hydrodynamic testing data in the territories of the Caspian Basin, Western Siberia and the Timan-Pechora gas and oil province. In 2006, he defended his thesis “Improving the interpretation of pulsed neutron logging data with PDK-100 equipment in the conditions of a terrigenous section of Western Siberia.”
From 2010 to the present, he has been working as a leading geophysicist in the department for monitoring the development of oil and gas fields and enhancing oil recovery. Participates in planning, monitoring and assessing the reliability of GTI, cable logging, logging drilling (MWD&LWD) data for production and exploration wells under construction. In addition, he works with materials from logging of horizontal wells, fiber optic systems and tracer studies.

Separate tasks are set for geophysical and petrophysical measurements during drilling. At the moment, the minimum set of LWD instruments includes gamma ray and resistivity logging, which in most cases allow solving geonavigation problems and obtaining a minimum set of geophysical data.
Most operating companies are trying to replace cable-based GIS with LWD equipment, which is not inferior in data quality and in some cases shows a more realistic picture. Therefore, methods such as acoustic logging, gamma-gamma density and neutron logging, and side logging are now common.

– MWD/LWD systems require highly qualified users. Where and how do drillers study and undergo training, capable of drilling shafts with pinpoint accuracy to a point determined by geologists or driving an extended shaft through a productive formation, especially if it is thin?
S.V. KOLBIN. The training of engineers repairing and operating telesystems was initially carried out in the training centers of equipment manufacturers. Now, mainly, training is carried out on the job, in telemetry units and in laboratories for repairing telemetry systems by leading specialists of the engineering and telemetry service. The qualifications of our specialists can be assessed as very high.

M.V. RAKITIN:

“At sea, unfortunately, we are significantly behind. The weakest sections in world-class logging drilling (MWD&LWD) are those that are drilled with bits of 311 mm or more. Apart from GK, EC and inclinometry, there is practically nothing here. Therefore, most people work with a GIS cable. This is where Russia can make a breakthrough, since non-standard approaches are required.”

I.A. Lyagov. Specialists of the Perfobur LLC company use the methods of VNIIBT, UGNTU, BashNIPIneft, TatNIPIneft to obtain analytical dependencies that establish the patterns of geometric parameters of small-sized configurations of the Perfobur Technical System with channel curvature, on the basis of which channel profiles with different radii of curvature are constructed for drilling a network of branched channels in thin layers.
M.V. RAKITIN. GIS drilling systems (MWD&LWD) for solving geosteering problems require highly qualified users. Schlumberger specialists work with GIS drilling equipment (MWD&LWD) to obtain all the necessary information. Control of input information and geonavigation with trajectory changes in real time is carried out under the guidance of the Customer’s specialists. As far as I know, we do not yet train geosteering specialists.

A.V. MIKHAILOV. Our company has a large number of advanced training courses, both with instructors in training centers in the USA and Russia, and online, which you can take in your free time from anywhere in the world, with only the Internet. These courses are a mandatory requirement for personnel development in the company. Another effective way to improve your skills is by exchanging experience on projects at other company locations. This allows you to see new facets and features of the work of service companies on other continents, with different mentalities and approaches to work. This experience allows us to bring something innovative to Russian projects.
Halliburton pays great attention to training and advanced training of its employees, as it understands that any mistake and lack of professionalism can result in non-productive time (NPT) for the Customer, failure of the OBD or MWD/LWD equipment, or failure to achieve the Customer’s geological goals.

Due to the fact that the general well stock in Russia is entering a period of declining production, the need will push for large-scale development of the Bazhenov Formation, the territory of which extends in Western Siberia over an area of ​​​​about 1 million km 2 with huge reserves - up to 140 billion tons of oil. Since the Bazhenov formation is characterized by low reservoir permeability, it must be drilled with horizontal wells followed by hydraulic fracturing (experience of the USA, Canada and other countries).

S.V. KOLBIN:

“The feasibility of drilling horizontal sidetracks is determined both by the expected increase in well production rates, the possibility of increasing the oil recovery factor of the reservoir and the field, and the return on investment. In the fields of Eastern Siberia, in conditions of low reservoir pressures, when drilling underbalanced using nitrogen-aerated oil as a flushing fluid, we drill two horizontal sections of 500 meters in length from each well, which has significantly increased flow rates.”

– Are we, in your opinion, technically and technologically ready to develop these natural resources, especially under sanctions?
V.V. KULCHITSKY. The kerogen-containing rock of the Bazhenov Formation is a non-reservoir; its basis is composed of silicites interspersed with clay interlayers. The stressed state of the rock mass is confirmed by buckling and cracking of the core material. Consequently, by technogenic impact it is possible to release the energy of the rock and trigger the mechanism of crack formation in the near-well space by directed formation unloading (DRP) in combination with hydraulic fracturing in horizontal wells with a large coverage area of ​​an artificially created branched system of cracks in the rock, which will serve as a reservoir in the BS. The structure of the subject of influence as a single microspace is complex and the methods of influencing it must be diverse, including geo-navigation technologies that ensure coverage of the deposit with lateral trunks in accordance with the laws of its formation. With a variety of secondary impact methods (thermal, chemical, physical), the main thing is the maximum approximation and positioning of the wellbore trajectory, taking into account the structural and textural characteristics of BS deposits.
Effective oil extraction on an industrial scale from BS oil source rocks, which have large geological reserves, seems impossible without the use of geonavigation technologies for constructing wells of complex spatial architecture in combination with thermal methods.
The idea of ​​​​developing technologies that accelerate the processes of release of organic matter into oil is to create appropriate thermodynamic conditions through the well construction of a complex spatial architecture - an underground reactor.
The team of authors (Kulchitsky V.V., Shchebetov A.V., Gutman I.S., Fomkin A.V., Boxerman A.A., Saakyan M.I.) created a method for developing a multilayer heterogeneous deposit of the Bazhenov formation in order to increase oil recovery of deposits due to the introduction into development of non-reservoir interlayers of the oil source strata BS [Method of developing a multi-layer heterogeneous oil field. Patent for invention RU No. 2567918 dated 12/02/2014]. Using the example of a patented georeactor well, it is shown that effective oil extraction on an industrial scale from BS oil source deposits by organizing the pyrolysis process over a large area without geonavigation technologies for constructing wells of complex spatial architecture seems impossible. A georeactor is a natural-technogenic structure for the thermal release of oil from autochthonous hydrocarbons, genetically related to the original organic matter and located in the sealed pores of oil source rocks, formed during the transition of part of solid organic matter to liquid.

MIKHAILOV Alexander Vladimirovich,

Halliburton company

Alexander Mikhailov has been the head of the technical solutions service (Solution Engineering) of the Sperry Drilling directional drilling division of the Halliburton company in Russia since 2015. This service includes such areas as optimization of well control, geosteering, interpretation of LWD data, and measurement correction service.
Alexander is a graduate of the Russian Geological Prospecting University. S. Ordzhonikidze, majoring in “Geophysical exploration of wells.” He began his professional career in oil and gas services as a telemetry engineer in 2008, then worked as an NNB engineer and leading NNB technical support specialist.

S.V. KOLBIN. Bazhenov deposits are a promising resource base for Surgutneftegas OJSC. We have experience in installing lateral trunks in Bazhen. Another thing is how and where to drill these shafts, what method of inducing inflow to use. This requires joint work with geologists and practical testing of theoretical concepts.
I.A. Lyagov. Currently in Russia there are technologies for the construction of multilateral wells that can compete with the Big Four companies.
A.V. MIKHAILOV. The Bazhenov Formation has not yet been fully explored. There are no specific approaches and technologies for its development. This is confirmed by most operating companies. At the moment, the reserves of the Bazhenov formation are unprofitable under the conditions of existing Russian and foreign technologies. It is impossible to draw a complete analogy between the unconventional reserves of Russia and the United States or Canada, therefore not all technologies of North American companies are suitable for our conditions.

– To what extent does import substitution meet the needs of the Russian market for geonavigation equipment, logging stations, rotary-steered systems, top drive systems, etc.?
V.V. KULCHITSKY. The creation of geonavigation technologies that will provide Russia with hydrocarbon raw materials for hundreds of years is always economically justified.
The problem in the development of geonautics, as the scientific and industrial basis of geosteering, is associated with high technologies created on the basis of fundamental research and discoveries. The interrupted century-old connection between academic science and industry has caused irreparable damage to industry institutions, which have always been a bridge connecting industry, academic and university science. In Russia, dozens of industry-specific oil and gas research institutes have completely perished, and the number of those remaining has decreased many times over, fragmenting into thousands of small enterprises. Experimental factories and installations have been lost, scientific and laboratory bases and design bureaus have degraded. Academic institutions, in an attempt to solve financial problems, wasted a quarter of a century on futile integration with oil and gas corporations, bypassing industry institutions. The “bridges” between academic science and industry—state sectoral institutions—have been burned. The systemic connection of RAS institutes with the oil and gas industry has been replaced by pseudo-scientific activities of private centers and research institutes of oil and gas corporations, where the administrative authorities manage scientific departments. Without restoring the system of industry institutes as conductors of academic science into oil and gas practice, it is impossible to implement the call of V.V. Putin at the Council under the President of the Russian Federation on Science and Education on January 21, 2016: “...The presence of our own advanced technologies is a key factor in the sovereignty and security of the state, the competitiveness of domestic companies, an important condition for economic growth and improving the quality of life of our citizens...” (quote from weekly newspaper of the scientific community of MSTU named after N.E. Bauman “Search”, No. 18 – 19 dated 05/13/2016).

I.A. LYAGOV:

“The economic efficiency of well construction depends on the quality of the hydrodynamic connection of the productive formation with the drilled well. If we consider drilling in a new field, then a horizontal channel (of course, of optimal length) allows you to build a well with a more effective filtration area, and therefore produce more oil with lower operating costs, but with higher drilling costs associated with the need to use expensive modern (innovative) equipment.”

S.V. KOLBIN. We mainly use domestic whipstocks, milling cutters, bits, downhole motors, top drives, and well completion equipment.
I.A. Lyagov. In recent years, due to the need for import substitution, a number of leading Russian companies have been developing rotary-steered systems and modern inclinometer telesystems for radial drilling. One of such companies is SKB PN JSC, whose specialists successfully cope with the market needs for high-quality equipment.
M.V. RAKITIN. At sea, unfortunately, we are significantly behind. The weakest sections in world-class logging drilling (MWD&LWD) are those that are drilled with bits of 311 mm or more. Apart from GK, EC and inclinometry, there is practically nothing here. Therefore, most people work with a GIS cable. Here it is Russia that can make a breakthrough, since non-standard approaches are required. More details on this issue can be found in the article by S.Yu. Shtunya, M.V. Rakitina – “Is it possible to overtake foreign companies in the field of GIS drilling (MWD&LWD)?” in your specialized magazine “Drilling and Oil” in No. 10 (October) 2016
A.V. MIKHAILOV. As far as I know, several Russian companies and bureaus have been developing high-tech NCD and MWD/LWD equipment for a long time as part of the import substitution program. However, the level of such equipment is still inferior to foreign analogues both in terms of reliability and functionality. Therefore, at the moment we can definitely say that domestic equipment cannot cover all the needs of oil and gas companies.
– Horizontal wells, as a rule, are more susceptible to collapses and rock slides, and therefore require careful selection of drilling fluid formulations. What drilling fluids do you use?
S.V. KOLBIN. To prevent complications when drilling sidetracks, we use a highly inhibited potassium chloride biopolymer solution, select formulations depending on the condition of the formation, and directly in workover teams we monitor up to 15 parameters of the drilling process around the clock.
I.A. Lyagov. The rheological properties and technological parameters of the flushing fluid are, of course, important in the process of rock destruction, the operation of the PDM, cutters and bits. To ensure sufficient carrying capacity, the Perfobur branched-directional (radial) drilling technology uses special solutions, for example, clay-free biopolymer inhibited drilling fluid of the Perfobur LLC formulation.
M.V. RAKITIN. Petroleum-based solutions are used to drill long horizontal holes.
A.V. MIKHAILOV. Obviously, to reduce the likelihood of the above-mentioned problems occurring, a deeper and broader analysis is required at the well planning stage. And in order to achieve the best results, a multidisciplinary approach to solving complex technical problems is required. Geomechanical modeling is an integral part of this approach. Now, thanks to geomechanical modeling, it is possible to select the optimal density and formulation of the drilling fluid. Also, with the help of specialists from the NNB Technical Solutions Center, together with mud service engineers, all necessary hydraulic calculations are prepared taking into account the BHA and drilling tools - to understand the expected equivalent circulating density (ECD), the effect of swabbing and pistoning, all risks are considered both during drilling, and during hoisting operations. Having the ability to obtain data on internal and casing pressure during drilling in real time from LWD sensors, it is possible to adjust fluid parameters in a timely manner, avoiding catastrophic consequences.

– Is drilling horizontal wells always economically justified? How much more expensive are they than vertical ones and is there a noticeable difference between the flow rates of horizontal and vertical wells with high formation permeability?
S.V. KOLBIN. The feasibility of drilling horizontal sidetracks is determined by both the expected increase in well production rates, the possibility of increasing the oil recovery factor of the reservoir and the field, and the return on investment. In the fields of Eastern Siberia, in conditions of low reservoir pressures, when drilling underbalanced using nitrogen-aerated oil as a flushing fluid, we drill two horizontal sections of 500 meters in length from each well, which has significantly increased production rates. Moreover, when drilling, we often get oil inflows.
I.A. Lyagov. The economic efficiency of well construction depends on the quality of the hydrodynamic connection of the productive formation with the drilled well. If we consider drilling in a new field, then a horizontal channel (of course, of optimal length) allows you to build a well with a more effective filtration area, and therefore produce more oil with lower operating costs, but with higher drilling costs associated with the need to use expensive modern (innovative) equipment.
And if we consider wells that are at a late stage of operation, then, in our opinion, the most optimal is the construction of a network of branched channels of small diameter and radius of curvature, which makes it possible to effectively open low-thickness layers and overcome contaminated bottomhole zones of the formation (BZZ) formed during its initial autopsy.
M.V. RAKITIN. Almost only horizontal wells are drilled for exploitation at sea. Already at the end of the last century, underwater wellhead equipment for horizontal wells began to be used.
GIS drilling (MWD&LWD) is increasingly beginning to be used in offshore exploration wells.
A.V. MIKHAILOV. This issue has been of interest to all oil and gas companies for several years. There are many scientific works proving that horizontal wells pay for themselves faster than vertical and directional wells, despite the fact that the cost of a horizontal well is 15–20% more expensive. Horizontal wells provide much greater opportunities to influence formations using various methods than vertical or directional wells.
Today, oil and gas drilling takes place in inaccessible areas, where it is sometimes impossible to fill the cluster directly above the development site or requires large financial costs - for the construction of additional roads and provision of transport links. In such conditions, it is simply impossible to hit geological targets by drilling vertical wells. And then horizontal drilling is the only possible way to get to productive formations.