What is a horizontal well. Design of a conventional horizontal well

This year, the Expocentre Fairgrounds will host an international exhibition on the topic “Oil and Gas Complex Technology Equipment.” One of the issues that will be presented is waterproofing in horizontal wells.

Currently, in the producing areas, watering is being actively combated and a number of works are being carried out to remove water from wells. This is a pressing issue that requires improvement and the search for new methods.

To eliminate water in wells, specific tasks are set:

1. They study the system for carrying out repair and insulation work, as well as waterproof materials.


2. A waterproofing method is being developed using a homogeneous solution, after pumping compressed gas into the formation.


3. They are testing new technologies based on a composition of gel and cement.


4. The issue of using a jet pump to clean the reservoir zone after waterproofing work is being investigated.

When carrying out waterproofing work in gas and oil wells, the following cementing materials are used: cement, biopolymers, liquid glass. They also make mixtures based on mineral and organic substances and make cement solutions. All of the above effectively helps prevent water from accumulating in wells.

Advantage of horizontal wells

Currently, the oil industry is experiencing a slow depletion of reserves and an increasing portion of them are located in hard-to-reach fields.

The difficulty of production is that they are characterized by high oil viscosity and sea shelves. The analysis and effectiveness of the use of horizontal wells is confirmed by the oil reserves that are recovered in Western Siberia and Russia, which total approximately 12 billion tons.

The use of horizontal technologies greatly increases the efficiency of reserve development. They imply the drilling process and, in fact, the horizontal wells themselves. They have the most significant extended zone.

During the construction of these wells, foreign and Russian equipment is used, and the main indicator is efficiency. They try to use domestic equipment as much as possible, but due to the lack of some necessary products, they have to resort to buying imported ones.

Despite the fact that the construction of horizontal wells is 10-15% more expensive than vertical wells, their use has many advantages:

• reduction in the total number of wells in the fields;


• increase in oil recovery level;


• attracting new deposits of oil reservoirs and high-viscosity oil into development.

Hydraulic fracturing (HF) is a popular method for intensive oil recovery when developing low-permeability reservoirs.

Multi-stage hydraulic fracturing in horizontal wells (MSHF) is the sequential implementation of hydraulic fracturing in one well. This method allows you to increase the level of profitability from oil production, while hydraulic fracturing in directional wells does not provide the required amount of profitability in development.

Multistage hydraulic fracturing is divided into 2 types: general technology and technology for using packer assemblies. The productivity of horizontal oil wells after hydraulic fracturing significantly increases the level of additional oil production and reduces drilling costs.

The main idea of ​​hydraulic fracturing is to change the geometry of the horizontal wellbore section and organize favorable conditions for the next hydraulic fracturing.

The scope of application of oil production wells with horizontal ends is quite extensive. It includes simplification of oil production from hard-to-reach fields, development of areas of complex rocks, etc.

It is reasonable to use this kind of wells for preliminary commercial production from the bowels of the earth.

Before oil production, the following actions are carried out:

1. Analysis and assessment of the feasibility of using formations. For preliminary degassing of highly gas-bearing coal seams, drilling advanced seam wells is the most optimal way to reduce gas emissions in the working faces and intermediate workings of coal mines. The suitable diameter of degassing wells is 80 - 250 mm, and the rational length is from 5 to 250 m. Wells for early degassing of coal seams.


2. A generalization of the conditions of use and the effectiveness of using horizontal wells in the development of gas and oil fields has proven that current technologies and special hardware make it possible to drill wells of almost any trajectory with a possible backlash of no more than 2 m. Horizontally branched wells are much more efficient than vertical ones. The use of such wells increases as the thickness of the formation decreases and the heterogeneity of its structure increases. One horizontal well can replace 5 vertical ones, and if we take into account the heterogeneity factor, the ratio can be 1:20.


3. Forecasting the possibility of using wells to extract methane from coal seams. The most developing coal methane deposits in Russia are the Pechora and Kuznetsk coal basins. A whole range of approaches has been developed to open up such places of the earth that carry out the profiles of horizontal wells.

All of the above actions are aimed at assessing the feasibility of developing coal methane deposits. Since the task is complex, it requires an even more detailed study of gas recovery from formations using horizontal wells, and many factors should be taken into account.

Features of the structure of a horizontal well

Design horizontal well directly depends on geological conditions. High productivity is achieved by drilling a well with a simple design using a rock-cutting tool.

It is recommended to drill wells in bedrock. When choosing a drilling rig design, they are guided by safety principles. In addition, the amount of material consumption and the final cost of construction depend on the choice made.

It is also taken into account that the curved and vertical part of a horizontal well is considered not only from the point of view of the correct choice of design, but also from the point of view of satisfactory bottomhole pressure. Only the horizontal part of the trunk is not taken into account.

There are basic requirements for a horizontal well:

• the completed structure should not allow destruction of the walls;


• provide sealing of the mouth;


• provide free access to the face.

The reliability of the entire structure depends on compliance with these requirements.

Elements of a horizontal well:

• cement shells;
• casing;
• inclined and vertical excavation.

To build this type of well, elements are selected with the help of which the set goal is achieved without incident and allows the operation of a horizontal well for a long time.

Casing horizontal wells leads to:

• stability of well walls in unstable rocks;


• isolation of absorption zones of flushing and formation fluid;


• delimitation of intervals of productive horizons and their isolation from water layers;


• formation of a proper channel for oil and gas production;


• installation of reliable wellhead equipment.

Study of horizontal wells

To obtain the maximum volume of hydrocarbon production, new technologies should be used and horizontal wells should be studied.

Careful study of them allows you to achieve the following results:

• increase the filtration area;


• improve the technology of underground gas storage:


• increase the intensity of injection into the reservoir.

In addition, based on research, it becomes possible to evaluate the productive use of horizontal wells in the development of viscous oil fields with moderate filtration and in cases where it is not possible to carry out full-fledged drilling operations. The disadvantage of horizontal wells is the expensive cost of their construction.

Technologies do not stand still, and if previously the price of horizontal wells was 8 times more expensive than vertical wells, now the difference has been reduced by 2 times. In the oil industry, the horizontal drilling method is used.

How are horizontal wells drilled?

The most popular is the mechanical method, which is aimed at destroying the rock. This type of well is often drilled in rocks of high categories, but recently also in rocks of medium hardness.

Technologies for drilling horizontal wells at the exhibition

The oil and gas industry is developing rapidly. Representatives of this industry will demonstrate their achievements in the oil and gas industry at the international exhibition "Neftegaz", which will take place at the Expocentre Fairgrounds.

You can visit the exhibition in the spring in Moscow. It is recommended to pre-register on the Expocentre website and receive email ticket to visit the exhibition. The event is dedicated to advanced technologies in this area.

Among the exhibitors there are Russian and foreign representatives. Their goal is to support and strengthen the company’s image, establish direct contacts with customers, and increase sales. One of the topics that will be sufficiently addressed in the project is horizontal wells, which occupy important place in the oil and gas industry.

The exposition uses new marketing and exhibition technologies, providing all those present with the most convenient conditions for creating business contacts in the B2B format.

"Neftegaz"– a powerful basis for business development and technology improvement.

As a result of using one of the drilling technologies, the created horizontal well must be deviated from the axis along which the vertical well passes at a certain depth level. This prevents the well from entering oil layers, since it must be located parallel to the oil layer.

Drilling is more relevant to the oil industry than to other industrial sectors. Drilling technology involves conducting a soil study before starting work. A documented permit is required to allow underground work to be carried out.

Horizontal wells, which are a type of inclined well, can be drilled using three different methods associated with the following types of drilling methods, including:

• directed;
• service installation;
• intra-fault directional.

The service installation method is often associated with the installation of internal underground communications, and with the intra-fault method, in coal deposits, which may be associated with a gas outlet.

Features of the technology

Due to the reduced productivity of obsolete wells, oil and gas producing companies are increasing production volumes through enhanced exploitation of developed oil fields.

An effective method for increasing the inflow of raw material production is based on HDD technology associated with horizontal drilling.

This method is associated with increasing the area of ​​oil or gas entering the wellbore. Typically, as a result of HDD, wells are formed that have horizontal sections, which is one of the drilling methods called directional drilling.

There are several aspects that make it possible to smooth out the impact of horizontal well drilling technology on environment. Production and technical methods include trenchless construction in places where high-voltage power lines are installed, in areas where dense residential buildings or highways are located.

The use of a high-tech drilling complex for drilling horizontal wells can significantly reduce working time. This does not require the involvement of a significant amount of equipment or labor force. There is no need to carry out the dewatering process if the groundwater is located at a higher level.

From the standpoint of the financial and economic aspect, by reducing the time required to complete the work, the estimated cost of pipeline construction is reduced. Efficiency when using units allows you to minimize all energy costs. The socio-ecological aspect is also important, related to minimizing the negative impact on people’s living conditions.

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Possible situations

The method not only allows increasing oil production volumes from fields that have already been in operation for a long time. At the same time, it is associated with the beginning of industrial development of areas previously considered ineffective, or areas with low profitability or its complete absence. It is advisable to use this method in several types of situations involving:

1. Breakage of the drill.
2. Places that are difficult to access due to difficult terrain or the proximity of reservoirs to oil production.
3. Development of deposits on the ocean or seabed.

If a drill breaks while drilling wells, which can happen due to excavation in very hard rocks, then it is often impossible to pull it out of the formation. This situation, that is, jamming of the drill, can be avoided by drilling the trunk at an angle to the original direction.

In certain situations, the vertical method of excavation is replaced by a horizontal one due to the complexity of the terrain, the proximity of the deposit to a reservoir, etc.

When drilling horizontally, using this method you can most comfortably reach the required formation, choosing a convenient place to start work.

If the deposit is located at the bottom of the sea or ocean, then the drilling process is associated with the lowest costs. If it is necessary to install a special offshore platform, the construction process and further operation will require significant costs. A similar situation may arise when constructing oil and gas storage facilities underground.

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Features of choice

The HDD process, which stands for horizontal directional drilling, is associated with the introduction of new technologies that make it possible to make wells that have a large deviation from the vertical axis. These capabilities are very valuable, since the location of layers containing oil is often horizontal. Horizontal wells have high productivity when compared with vertical wells made in the same layers containing oil.

Carry out penetration in layers in the established technological mode drilling, which is typical for HDD. In this case, the entire process must be combined with clearly defined operating conditions for the installation, that is, a device that destroys the bottom of a horizontal well. The destruction efficiency indicators are the following:

1. The load on the device (bit) associated with axial pressure.
2. The number of revolutions when rotating the bit.
3. The level of quality of clay in the layers and its quantity.
4. Method of feeding tools for slaughtering, etc.

If we take into account the complex of all factors characteristic of the drilling process mode, we can identify the drilling method that is the most effective. In this case, the fulfillment of working conditions usually corresponds. Therefore, compliance with the optimal conditions of the drilling mode technology is combined with an increase in penetration efficiency indicators as a result of horizontal drilling.

The drilling point may be located in relation to the layers containing oil, often at a certain distance of several kilometers, so the result will be related to positive effect. The vertical drilling method can cause significant damage to environmental cleanliness in the areas where deposits are located, therefore the method of creating horizontal wells is optimal.

The advantage of HDD is the preservation of the existing ecological balance and natural landscape. The drilling process is not associated with technogenic impact on the landscape, which does not harm existing flora and fauna. The negative impact on the living conditions of the population of the area where oil-bearing layers are being drilled is minimized.

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Preparatory work

The process of drilling horizontal wells for oil or gas, as well as other types of minerals, can be carried out using a deep drilling rig. For this purpose, a geological and technical work order and a regime and technical map are being drawn up. The process of performing work is determined by the technological regulations.

The main stages of the drilling process include the following types of operations:

1. Laying and assembling drilling tools.
2. Carrying out hoisting and hoisting operations using automation.
3. Oriented drilling.
4. Creation of drilling fluid.
5. Operations for weighting and chemical treatment of drilling fluid.
6. Sealing the mouth of horizontal wells.
7. Suppression of gas and oil shows.
8. Preparation of drilled wells for geophysical research.
9. Preparing a horizontal well to receive a formation tester.
10. The use of roll selection projectiles for the purpose of roll selection.
11. Development of a horizontal well.
12. Transportation of complex drilling machines.

During each stage, additional control is exercised over the properties of the prepared solution through a thorough analysis of the solution purification system. Blowout prevention units should be provided for wellheads, which will reduce the negative result from possible accidents during drilling.

Level technical condition underground and surface drilling equipment must be subject to timely operational control. To check the correctness of all processes, control and measuring instruments are used in good condition, as well as automatic machines and safety devices.

All complications during drilling must be eliminated. After preparing the well, work related to testing of formations must be carried out. After each drilling, all used equipment must undergo mandatory preventive repair, installation and dismantling.

Horizontal wells have been used effectively in the following cases:

• 1. In fractured reservoirs, horizontal wells have been used to intersect fractures to effectively drain the reservoir (examples: Bakken formation, North Dakota, USA; Austin Chalk, Texas, USA and Devonian Shale, West Virginia, USA).
• 2. In reservoirs with the risk of water and gas breakthroughs, horizontal wells have been used to minimize water cut problems and increase oil production (for example: Rospo Mage field, offshore drilling, Italy; Helder field, offshore drilling, the Netherlands; Bima field, Indonesia; Prudhoe Bay, State Alaska, USA and Empire Abo Unit, New Mexico, USA).
• 3. In gas production, horizontal wells can be used in both low-permeability and high-permeability reservoirs. In low-permeability reservoirs, horizontal wells can improve the drainage area and reduce the number of wells required to drain the reservoir. In highly permeable reservoirs where near-wellbore gas velocities are high in vertical wells, horizontal wells can be used to reduce near-wellbore gas velocities. Thus, horizontal wells can be used to reduce turbulence in the near-well zone and increase well productivity in reservoirs with high permeability. The recent application of horizontal drilling technology to the Zuidwal gas field in the Netherlands confirms the effectiveness of horizontal wells in reducing near-wellbore turbulence.
• 4. Horizontal wells were used to increase oil recovery, especially with the use of thermal methods of influencing the formation. A long horizontal well provides a larger contact area with the reservoir and therefore increases the injectivity of the injection well. This is especially beneficial in enhanced oil recovery applications where injectivity is an issue. Horizontal wells were also used as production wells.

Proper orientation of horizontal wells, especially in fractured reservoirs, can also improve displacement efficiency during enhanced oil recovery. Recently, horizontal wells have been used in flooded areas to inject polymers and other agents to improve oil displacement efficiency.

Other applications of horizontal wells are mainly related to overcoming the financial problems caused by drilling. In offshore fields, in remote fields in pollution-sensitive areas where project costs can only be reduced by minimizing the number of wells that are required to drain a given reservoir, horizontal wells are highly preferred. In these cases, horizontal wells provide unique advantages. For example, when drilling offshore wells, the cost of maintaining a platform is proportional to the number of wells that can be drilled from that platform. Extended horizontal wells can not only be used to reduce the number of wells required to drain a given volume of reservoir, but they can also increase the volume of reservoir that can be drained from a single platform and significantly reduce project costs. Similarly, in pollution-sensitive areas and in fields located under cities, horizontal ones (wells can be used to drain a large volume of reservoir with minimal surface damage from an environmental point of view).

Table 1.1 Drilled horizontal wells

For most people, having your own oil or gas well means deciding financial problems for the rest of your life and live without thinking about anything.
But is it so easy to drill a well? How is it structured? Unfortunately, few people ask this question.

Drilling well 39629G is located very close to Almetyevsk, in the village of Karabash. After the night rain, everything around was foggy and hares kept running in front of the car.

And finally, the drilling rig itself showed up. The rig foreman was already waiting for us there - the main person on the site, he makes all operational decisions and is responsible for everything that happens during drilling, as well as the head of the drilling department.

Fundamentally, drilling refers to the destruction of rocks at the bottom (at the lowest point) and the extraction of the destroyed rock to the surface. A drilling rig is a complex of mechanisms, such as a drilling rig, mud pumps, drilling mud cleaning systems, generators, living quarters, etc.

The drilling site on which all the elements are located (we will talk about them below) is an area cleared of the fertile layer of soil and filled with sand. After completion of the work, this layer is restored and, thus, no significant harm is caused to the environment. A layer of sand is required, because... At the first rains, the clay will turn into an impassable slurry. I myself saw how multi-ton Urals got stuck in such slurry.
But first things first.

At well 39629G, a rig (actually a tower) SBU-3000/170 (stationary drilling rig, maximum lifting capacity 170 tons) was installed. The machine is made in China and compares favorably with what I have seen before. Drilling rigs are also produced in Russia, but Chinese rigs are cheaper both to purchase and to maintain.

Cluster drilling is being carried out at this site; it is typical for horizontal and directional wells. This type of drilling means that the wellheads are located at close distances from each other.
Therefore, the drilling rig is equipped with a self-moving system on rails. The system works on the “push-pull” principle and the machine seems to move itself with the help of hydraulic cylinders. It takes a couple of hours to move from one point to another (the first tens of meters) with all the accompanying operations.

We go up to the drilling site. This is where most of the drillers' work takes place. The photo shows the pipes of the drill string (on the left) and a hydraulic wrench, with the help of which the string is extended with new pipes and continues drilling. Drilling occurs thanks to a bit at the end of the column and rotation, which is transmitted by a rotor.

I was particularly delighted workplace driller Once upon a time, in the Komi Republic, I saw a driller who controlled all processes with the help of three rusty levers and his own intuition. To move the lever from its place, he literally hung on it. As a result, the drill hook almost killed him.
Here the driller is like the captain of a spaceship. He sits in an isolated booth, surrounded by monitors, and controls everything with a joystick.

Of course, the cabin is heated in winter and cooled in summer. In addition, the roof, also made of glass, has a protective net in case something falls from a height and a wiper for cleaning the glass. The latter causes genuine delight among drillers :)

Let's climb up!

In addition to the rotor, the rig is equipped with a top drive system (made in the USA). This system combines a valve block and a rotor. Roughly speaking, this is a crane with an electric motor attached to it. The top drive system is more convenient, faster and more modern than a rotor.

Video of how the top drive system works:

From the tower you have a great view of the site and the surrounding area :)

In addition to beautiful views, at the top point of the drilling rig you can find the workplace of a riding pombur (driller's assistant). His responsibilities include pipe installation work and general supervision.

Since the horseman is at the workplace for the entire 12-hour shift and in any weather and at any time of the year, a heated room is equipped for him. This never happened on the old towers!

In the event of an emergency, the rider can evacuate using a trolley:

When a well is drilled, the trunk is washed several times to remove drilled rock (sludge) and a casing string, which consists of many pipes twisted together, is lowered into it. One of the typical internal diameters of the casing is 146 millimeters. The length of the well can reach 2-3 kilometers or more. Thus, the length of the well exceeds its diameter by tens of thousands of times. For example, a piece of ordinary thread 2-3 meters long has approximately the same proportions.

Pipes are fed through a special chute:

After running the casing, the well is flushed again and cementing of the annulus (the space between the well wall and the casing) begins. Cement is fed to the face and forced into the annulus.

After the cement hardens, it is checked with a probe (a device lowered into the well) AKTs - acoustic cementation control, the well is pressurized (checked for leaks), if everything is OK, then drilling continues - the cement cup is drilled at the bottom and the bit moves on.

The letter “g” in well number 39629G means that the wellbore is horizontal. From the wellhead to a certain point, the well is drilled without deviation, but then, with the help of an articulated whipstock and/or a rotary whipstock, it goes horizontal. The first is a pipe with a hinge, and the second is a bit with a directional nozzle, which is deflected by the pressure of the drilling fluid. Usually, in pictures, the barrel deflection is depicted at almost an angle of 90 degrees, but in reality this angle is about 5-10 degrees per 100 meters.

To ensure that the well bore goes where it needs to go, special people - “sinkers” or telemetry engineers. Based on readings of the natural radioactivity of rocks, resistance and other parameters, they monitor and adjust the drilling course.

Schematically it all looks like this:

Any manipulation with anything at the bottom (bottom) of a well turns into a very exciting activity. If you accidentally drop a tool, a pump or several pipes into a well, then it is quite possible that you will never get what you dropped, after which you can give up on a well worth tens or hundreds of millions of rubles. By delving into cases and repair stories, you can find real pearl wells, on the bottom of which there is a pump, on top of which lies a fishing tool (for removing the pump), on top of which lies a tool for extracting the fish
nal tool. In my presence, they dropped, for example, a sledgehammer into a well :)

In order for oil to flow into the well at all, holes must be made in the casing and the cement ring behind it, since they separate the reservoir from the well. These holes are made using shaped charges; they are essentially the same as, for example, anti-tank ones, only without a fairing, because they don’t need to fly anywhere. The charges penetrate not only the casing and cement, but also the formation itself rock several tens of centimeters deep. The whole process is called perforation.

To reduce tool friction, remove destroyed rock, prevent shedding of the well walls and compensate for the difference in reservoir pressure and pressure at the wellhead (at the bottom the pressure is several times greater), the well is filled with drilling fluid. Its composition and density are selected depending on the nature of the cut.
The drilling fluid is pumped by a compressor station and must constantly circulate in the well to avoid shedding of the well walls, tool sticking (a situation where the string is blocked and it is impossible to rotate or pull it out - this is one of the most common drilling accidents) and other things.

We get down from the tower and go look at the pumps.

During the drilling process, the drilling fluid carries cuttings (drilled rock) to the surface. By analyzing cuttings, drillers and geologists can draw conclusions about the rocks that the well is currently passing through. Then the solution must be cleaned of sludge and sent back into the well to work. For this purpose, a system of treatment plants and a “barn” are equipped, where the purified sludge is stored (the barn is visible in the previous photo on the right).

The vibrating sieve is the first to take the solution - they separate the largest fractions.

The solution then passes through sludge (left) and sand separators (right):

And finally, the finest fraction is removed using a centrifuge:

Then the solution enters the capacitive blocks, if necessary, its properties are restored (density, composition, etc.) and from there it is fed back into the well using a pump.
Capacitive block:

Mud pump (made in Russia!). The red thing on top is a hydraulic compensator; it smoothes out the pulsation of the solution due to back pressure. Typically, drilling rigs have two pumps: one is working, the second is a backup in case of breakdown.

All this pumping equipment is managed by one person. Due to the noise of the equipment, he wears earplugs or ear protection throughout his shift.

“What about the daily life of drillers?” - you ask. We didn’t miss this moment either!
Drillers work at this site in short shifts of 4 days, because... drilling is taking place almost within the city, but the residential modules are practically no different from those used, for example, in the Arctic (except for the better).

There are a total of 15 trailers on the site.
Some of them are residential, where drillers live for 4 people. The trailers are divided into a vestibule with a hanger, washbasin and cabinets, and the living part itself.

In addition, a bathhouse and a kitchen-dining room are located in separate trailers (in local slang - “beams”). In the latter, we had a wonderful breakfast and discussed the details of the work. I won’t retell the story, otherwise you’ll accuse me of very frank advertising, but I’ll say , that I immediately wanted to stay in Almetyevsk... Pay attention to the prices!

We spent about 2.5 hours at the rig and I once again I became convinced that such a complex and dangerous business as drilling and oil production in general can only be carried out good people. They also explained to me that bad people don’t stay here.

Friends, thank you for reading to the end. I hope now you understand the process of drilling wells a little better. If you have any questions, ask them in the comments. I myself or with the help of experts will definitely answer!

Environmental justification for the advantages of constructing horizontal wells.

A horizontal well is a well that has a fairly extended filter zone, comparable in length to the vertical part of the wellbore, drilled primarily along the bedding between the roof and the bottom of the oil or gas reservoir in a certain azimuthal direction. The main advantage of horizontal wells compared to vertical ones is an increase in flow rate from 2 to 10 times due to the expansion of the drainage area and an increase in the filtration surface.

Based on statistical reporting Based on the actual operating conditions of wells at the Orenburg oil and gas condensate field, we can conclude that currently drilled horizontal wells are, on average, 2 times more preferable than vertical wells in terms of production characteristics.

The environmental benefits of constructing horizontal wells are due to the reduction of man-made impacts on the environment, reduction of losses and damage to the natural environment.

When constructing one horizontal (conditionally horizontal) well instead of two vertical ones, the following are reduced:

Areas of land to be taken;

Volumes of production and consumption waste generation;

Emissions of harmful substances into the atmospheric air.

4.3.1 Characteristics of the drilling rig as a source of technogenic impact on the environment

The construction of wells has a technogenic impact on the natural environment, from the surface of the earth to the deepest depths.

The surface impact on the environment during well construction is associated with the seizure and disturbance of land, the formation and disposal of production and consumption waste, as well as the release of pollutants into the air.

The following main stages of well construction are distinguished:

Construction and installation works;

Direct well drilling;

Inducing a gas influx and testing a well for productivity, in which certain types of surface impact on the natural environment prevail.

During construction and installation work, land is disturbed. In this regard, the main measure to reduce the technogenic impact on soils is to reduce the area of ​​withdrawn land through rational (compact) placement of drilling rig equipment.

At the stage of well drilling, the main technogenic impact on the environment comes from drill cuttings, drilling fluids, waste water, fuels and lubricants and chemical reagents.

In order to reduce the technogenic impact on the environment, at this stage of well construction, measures are taken to prevent the spreading of drilling fluids and drilling fluids throughout the drilling site and their penetration into the upper aquifers.

When a gas influx is triggered and a well is tested for productivity, a short-term but quite powerful release of harmful substances into the atmosphere occurs.

During this period, the main source of pollutant emissions is the flare unit and the diesel power plant. Pollutants entering the atmospheric air include: nitrogen oxides, sulfur dioxide, carbon monoxide, hydrogen sulfide, hydrocarbons, mercaptans, soot.

For the construction of one well (both vertical and conditionally horizontal), 3.5 hectares of land are allocated for temporary use for a period of 2 years. Upon expiration of the period of use, the land must be restored to its original condition and transferred to the land user for further use for its intended purpose.

In order to reduce the negative impact on soils, after completion of well construction, technical and biological reclamation is carried out on lands allocated for temporary use.

Technical reclamation includes:

cleaning the area from debris, concrete, contaminated soil;

leveling potholes and holes;

applying and leveling the fertile layer;

compaction of the fertile layer;

spring plowing and harrowing of construction strips.

Technical reclamation work must be completed within a year after completion of drilling operations and dismantling of equipment.

Biological land reclamation is carried out with the aim of completely restoring the fertility of the land for its further use for its intended purpose. To do this, treat the applied soil layer:

Apply mineral fertilizers to improve the nutritional status of soils (superphosphate, complex fertilizers, potassium sulfate);

Organic fertilizers are applied to increase the content of organic matter and increase the microbiological activity of soils;

Grasses are sown (in fodder crop rotations), annuals, perennials, cereals and legumes to restore or form the root layer and enrich it with organic matter.

They carry out deep loosening, sealing off moisture, and cultivating crops.

During the construction of wells, production and consumption waste is generated in the volumes presented in Table 4.2.

Table 4.2 – Volumes of production and consumption waste generated during the construction of wells at the ONGCF.

As can be seen from Table 4.2, the bulk of waste (up to 94.5%) consists of waste of the fourth hazard class, which is drill cuttings and waste drilling fluids. Moreover, during the construction of conditionally horizontal wells, with a horizontal displacement of the bottom by 500 m, the volumes of formation of drill cuttings and waste drilling fluids are 7% higher than the volumes of waste generation during the construction of vertical wells. This is due to additional drilling work to open the productive formation with a horizontal wellbore.

In order to reduce the technogenic impact on the environment, production and consumption waste generated during the construction of wells is disposed of at specialized disposal sites.

Emissions of harmful substances during well construction are short-term in nature and depend on the duration of construction, which is determined by well drilling projects.

During the period of construction and installation work and drilling wells, sources of pollutant emissions are: vehicles, a diesel power plant, the chimney of a boiler plant, exhaust pipes of diesel units (when using machines with a diesel drive), breathing valves of fuel and lubricants tanks, the ventilation system of the pump room and the preparation unit drilling fluid.

At this stage of well construction, in order to reduce emissions of pollutants into the atmosphere, it is recommended that wells be drilled mainly with electric-driven drilling rigs.

At the final stage of well construction, the well is developed and tested for productivity. Development and testing of wells after drilling is carried out in three modes. The duration of the research does not depend on the type of well and is 72 hours.

This period is accompanied by a short-term, but quite powerful release of harmful substances into the atmosphere from all types of wells under study. The source of pollutant emissions is a flare unit, from which pollutants are released into the atmospheric air: nitrogen oxides, sulfur dioxide, carbon monoxide, hydrogen sulfide, hydrocarbons, mercaptans, soot.

The most effective measure to reduce technogenic impact at this stage of well construction is the introduction new technology well development using mobile separation units, for example, Geo-Test.

Emissions of pollutants into the atmosphere during the construction of new wells are shown in Table 4.3.

Table 4.3 – Volumes of pollutant emissions into the atmosphere during well construction