Methods of drilling wells for oil and gas. General information about drilling oil and gas wells. Almetyevsk State Oil Institute

It is important to note that the drilling of oil and gas wells can only be carried out with the strictest observance of all rules and requirements. And this is not at all surprising, because you have to work with a rather dangerous and sensitive material, the extraction of which in any case requires a competent approach. And in order to understand all aspects of working with such, it is necessary first of all to consider all the basics of this case and its components.

So, a well is called a mine working, which is created without the need for access inside a person and has a cylindrical shape - its length is many times greater than the diameter. The beginning of the well is called the mouth, the surface of the cylindrical column is called the trunk or wall, and the bottom of the object is called the bottom.

The length of the object is measured from the mouth to the bottom, while the depth is measured by the projection of the axis onto the vertical. The initial diameter of such an object at the maximum does not exceed 900 mm, while the final diameter in rare cases is less than 165 mm - this is the specificity of the process called drilling of oil and gas wells and its features.

Features of drilling oil and gas wells

The creation of wells as a separate process consists mostly of drilling, and it, in turn, is based on the following operations:

• The process of deepening when destroying rocks with a drilling tool,


• Removal of crushed rock from the well,


• Strengthening the shaft with casing strings as the mine deepens,


• Performance of geological and geophysical works to search for productive horizons,


• Production string cementing.

Classification of oil and gas wells

It is known that the necessary materials that are planned to be mined can occur at different depths. And therefore, drilling can also be performed at different depths, and at the same time, if we are talking about a depth of up to 1500 meters, drilling is considered shallow, up to 4500 - medium, up to 6000 - deep.

To date, drilling of oil and gas wells is carried out at ultra-deep horizons, deeper than 6000 meters - in this regard, the Kola well is very indicative, the depth of which is 12650 meters.

If we consider drilling methods, focusing on the method of destruction of rocks, then here we can cite as an example mechanical methods, for example, rotational, which are implemented using an electric drill and screw-type downhole motors.

There are also percussion methods. And they also use non-mechanical methods, among which are electropulse, explosive, electrical, hydraulic and others. All of them are not widely used.

Works while drilling for oil or gas

In the classic case of drilling for oil or gas, drill bits are used to break the rock, and flushing fluid flows constantly clean the bottomhole. In rare cases, a gaseous type working reagent is used for purge.

In any case, drilling is carried out vertically, inclined drilling is used only when necessary, and cluster, directional, double-lateral or multilateral drilling is also used.

Deepening of wells is carried out with or without core sampling, the first option is used when working along the periphery, and the second - over the entire area. If the core is taken, it is examined for the passed rock layers, periodically lifting it to the surface.

Drilling for oil and gas is carried out today both onshore and offshore, and such work is carried out using special drilling rigs that provide rotary drilling using specialized drill pipes that are connected by socket and lock threaded connections.

Also, sometimes continuous flexible pipes are used, which are wound on drums and can have a length of about 5 thousand meters or more.

Thus, such works cannot be called simple by any means - they are very specific and complex, and special emphasis here should be placed on new technologies, the study of which can be a difficult task even for professionals in this industry.

New technologies for drilling oil and gas wells at the exhibition

Sharing information and learning about innovations can ensure optimal progress, and therefore such a need simply cannot be left aside.

If you decide to join modern achievements and plunge into the professional environment, professional events are held for this purpose, and you should definitely take part in one of them. We are talking about exhibitions that are held annually at the Expocentre Fairgrounds and gather hundreds and thousands of specialists in this area during the opening days.

At the annual oil and gas exhibition you can easily access new developments, study advanced technologies (for example, oil and gas drilling technologies), see modern equipment and at the same time acquire useful contacts in the required volume, find customers and partners.

Opportunities like these are not to be missed, because they don't come around very often and can make a big difference if done right!

Read our other articles.

Drilling is the construction of a mining directional working of small diameter and great depth. The mouth of the well is located on the surface of the earth, and the bottom is located at the bottom. Today, drilling of oil and gas wells for the extraction of the corresponding minerals is widespread.

Tasks and goals of drilling for oil and gas

Today, oil and gas are extracted from wells. Despite the large number of different ways to make a well, they are still developing, new methods are being developed to speed up the work and reduce the cost of their cost.

The modern drilling process consists of the following steps:

• shaft sinking
• Separation of layers
• Well development and operation

The drilling of wells is divided into two stages, which should take place in parallel to each other: the deepening of the bottom and its cleaning from destructible rocks. Separation of rocks is also carried out in two stages: installation of casing pipes, their joining and sealing with each other.

Despite the fact that at home no one will drill an industrial well for oil and gas, it is interesting to know how much an oil well costs and which methods are most widely used.

Oil drilling process - video

Basic drilling methods

Today, various methods of drilling oil wells are practiced, but the most common among them are:

• Rotary drilling with a caisson for a well
• Turbine drilling
• Screw drilling

Rotary drilling of oil wells is one of the popular methods. The chisel, passing into the depths of the soil rocks, rotates together with the drill pipes. The torque of such a system, first of all, depends on the resistance of the rocks that come across on the way.

Rotary well drilling owes its popularity to such advantages as the ability to withstand large WOB fluctuations, independence of settings from extraneous factors, and a large passage in one run.

Turbine drilling of wells for oil is carried out by means of an installation in which the bit interacts with the turbodrill turbine. The unit is driven into rotation by a fluid flow that circulates under high pressure through a system of stators and rotors. Due to this, including the lifting and pumping of well water.

Torque is independent of well depth, rock properties, rotational speed and axial load. At the same time, the transmission coefficient in turbine drilling is an order of magnitude higher than in rotary drilling, but the cost of work is higher due to the need for a large amount of energy, it is impossible to quickly reconfigure the installation parameters.

Screw drilling of oil and gas wells lies in the fact that the main working mechanism consists of a large number of screw mechanisms, due to which the optimal speed of the bit is achieved. Despite all the prospects, this method has not yet received proper distribution, but it has a huge potential for this.

Issue price

Having found out for yourself how oil wells are drilled, the question of how much it takes to drill the next meter of the funnel becomes interesting.

Today, the cost of drilling an oil well is very huge and depends on a large number of factors:

• Well depth
• The need to purchase casing plastic pipes for wells
• Ambient conditions
• Deadlines

If we talk about exact figures, then the price of a well with a depth of 2000-3000 meters will be from 30 to 60 million rubles. Exploratory drilling will cost about 40-50% of the cost of drilling.

Vladimir Khomutko

Reading time: 5 minutes

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What is an oil well?

It is difficult to imagine modern life without oil products. They are made from oil, which is extracted with the help of special mine workings. Many of us have heard the term "oil well", but hardly everyone knows what it actually is. Let's try to figure out what this building is, and what they are.

A well is a cylindrical mine working, whose diameter is many times less than the total length of its shaft (depth).

In addition to the well, there are also such mine workings as a well and a mine. How do they differ from our definition? In fact, everything is quite simple. A person can get into a mine or a well, but not into a well. Thus, an additional definition of this structure is as follows - a mine working, the scheme and shape of which excludes human access to it.

The upper part of such a working is called the mouth, and the lower part is called the face. The walls going down form the so-called trunk.

Everyone knows that wells are made by drilling. However, to say that they are just Buryats would be wrong. These capital structures, complex in their structure, are more likely to be built underground, in connection with which they are classified as fixed assets of the organization, and the costs of drilling and equipping them are capital investments.

Construction of oil and gas wells

The design of the well is selected at the design stage and must meet the following requirements:

• the design should provide the possibility of free access to the bottom of geophysical instruments and downhole equipment;
• the design must prevent the collapse of the walls of the trunk;
• it must also provide reliable separation from each other of all passable layers and prevent fluids from flowing from layer to layer;
• if necessary, the design of this working should make it possible to seal its mouth in case of such a need.

Construction and installation of oil and gas wells is carried out as follows:

1. The first step is to drill the initial hole of a large diameter. Its depth is about 30 meters. Then a metal pipe, which is called a direction, is lowered into the drilled hole, and the space surrounding it is lined with special casing pipes and cemented. The task of the direction is to prevent the erosion of the upper soil layer in the process of further drilling.
2. Further, to a depth of 500 to 800 meters, a shaft of a smaller diameter is drilled, into which a string of pipes, called a conductor, is lowered. The space between the walls of the pipe and the rock is also filled with cement mortar to the full depth.
3. Only after the arrangement of the direction and the conductor, the well is drilled to the depth specified by the project, and a string of pipes of an even smaller diameter is lowered into it. This column is called operational. If the formation depth is large, then it is possible to use the so-called intermediate tubing strings. The entire space between the wellbore and the surrounding rock is filled with cement.

What is the main purpose of a conductor? The fact is that at depths of up to 500 meters there is an active zone of fresh waters, and below this depth (depending on the region of development) a zone with difficult water exchange begins, in which there is a lot of salt water and other mobile fluids (including gases and oil). ). So, the main task of the conductor is additional protection, which prevents salinization of surface fresh water and does not allow harmful substances that are concentrated in the lower layers to penetrate into them.

What are wells?

Depending on the geological conditions in which oil fields are located, different types of such workings are drilled.

Main types of wells:

• vertical;
• obliquely directed;
• horizontal;
• multilateral or multilateral.

A well is called vertical if the angle of deviation of the wellbore from the vertical is not more than five degrees.

If this angle is more than five degrees, then this is already an obliquely directed type.

A well is called horizontal if the angle of deviation from the vertical of its wellbore is approximately equal to 90 degrees. However, there are some nuances to this definition. Since “straight lines” are rarely found in wildlife, and the developed reservoirs most often lie with some slope, then from a practical point of view, drilling strictly horizontal wells, as a rule, does not make sense.

It is easier and more efficient to direct the trunk along the optimal trajectory of occurrence. Based on this, it is possible to define the horizontal type of such workings as a well, which has an extended shaft, drilled as close as possible to the direction of the target productive formation, while maintaining the optimal azimuth.

Wells with two or more wellbores are called multilateral or multilateral wells. Their difference from each other is in the location of the branching point, in which additional ones depart from the main table. If this point is located above the level of the productive horizon, then this type of development is called multilateral. If this point is located within the productive horizon, then this is a multilateral type of well.

Simply put, if the main wellbore is drilled to the reservoir under development, and additional offshoots are drilled inside it, then this is a multilateral type (the productive reservoir breaks through at one point). All other workings with several shafts are referred to as multilateral (several points of formation penetration). Also, this type of wells is typical in cases where the layers are located at different horizons.

In addition, there are cluster wells. In this case, several trunks diverge at different angles and to different depths, and their mouths are close to each other (like a bush planted upside down).

This classification provides for the following categories of such mine workings:

Exploratory drilling is carried out in areas whose oil or gas content has already been established in order to clarify the volumes of discovered hydrocarbon deposits and to clarify the initial parameters of the field, which are necessary when designing a field development method, therefore special attention is paid to exploration.

Production drilling creates workings of the following types:

• main (producing and injection);
• reserve;
• control;
• appraisal;
• duplicating;
• wells for special purposes (absorption, water intake, and so on).

The extraction of raw materials itself is carried out through mining workings, which are pumping, gas lift and fountain.

The purpose of injection wells is to influence the reservoir under development by injecting steam, gas or water into it, as well as other working media. They are intra-contour, near-contour and contour.

Reserves are necessary for the development of separate and stagnant zones, as well as wedging zones that are not included in the contour of the main wells.

The control ones are needed to monitor the current position of the zones of contact between the extracted resource and water and other changes in the reservoir under development. In addition, they control the pressure in productive formations.

Estimated ones are needed for a preliminary assessment of deposits being prepared for development. They help to determine the boundaries and sizes of reserves, as well as other necessary preliminary parameters.

Duplicating ones are used during the replacement of wells of the main stock that are being liquidated due to physical wear or accidents.

Technical water is extracted through special ones, commercial water is discharged, open fountains are eliminated with their help, and so on.

The process of drilling an oil well, according to the nature of its impact on rocks, is:

• mechanical;
• thermal;
• physical and chemical;
• electric and so on.

Oil well construction

Industrial development of deposits implies the use of only mechanical methods that use different drilling modes. All other drilling methods are under experimental development.

Mechanical drilling methods are divided into rotary and percussion.

The impact method is the mechanical destruction of rock, which is performed by a special tool suspended on a rope - a chisel. The structure of such a drilling complex also includes a rope lock and a shock rod. This device is suspended on a rope, which is thrown over a block mounted on a drilling mast. The reciprocating movement of the bit is provided by a special drilling machine. The barrel acquires a cylindrical shape due to the rotation of the bit during operation.

The bottomhole is cleaned from the destroyed rock using a bailer, which resembles a long bucket with a valve on the bottom. The tool is removed from the barrel, the bailer is lowered, its valve is opened in the bottomhole. The bucket is filled with liquid with pieces of rock, the valve closes, and the full bailer raises to the surface. Everything, you can continue drilling.

In Russia, percussive drilling is practically not used at the moment.

The rotational method is based on immersing the bit into the rock mass by simultaneously exposing the tool to both vertical load and torque. The vertical load allows the bit to plunge into the rock and then, with the help of torque, the bit shears, wears and crushes the rock.

According to the way the power unit is located, rotary drilling is divided into rotary and downhole drilling. In the first case, the engine is on the surface, and the torque is transmitted to the bottom by the drill pipe strings. In the second case, the engine is placed immediately behind the bit, and the drill string does not rotate (only the bit rotates).

The deepest well in the world is the Kola Superdeep (SG-3). Its depth is 12,262 meters. It was drilled in the Murmansk region to study the deep structure of the Earth.

Topic: Drilling of oil and gas wells.

Plan: 1. General information about oil and gas operations.

2. Ways of drilling wells.

3. Classification of wells.

1. General information about oil and gas operations.

Well drilling is the process of constructing a directional mine working of great length and small (compared to length) diameter. The beginning of the well on the surface of the earth is called the mouth, the bottom is called the bottom. This process - drilling - is common in various sectors of the national economy.

Goals and objectives of drilling

Oil and gas are produced using wells, the main construction processes of which are drilling and casing. It is necessary to carry out high-quality construction of wells in ever-increasing volumes with a multiple reduction in the terms of their drilling, as well as with a decrease in labor and energy intensity and capital costs.

Well drilling is the only method of effective development, increment of oil and gas production and reserves.

The cycle of construction of oil and gas wells before putting them into operation consists of the following successive links:

sinking of the wellbore, the implementation of which is possible only when two types of work are carried out in parallel - deepening the bottomhole through local destruction of rock and cleaning the shaft from destroyed (drilled) rock;

separation of layers, consisting of consecutive works of two types - fixing the walls of the wellbore with casing pipes connected into a casing string, and sealing (cementing, plugging) of the annulus;

well development as a production facility.

2. Ways of drilling wells.

Common methods of rotary drilling - rotary, turbine and electric drill drilling - involve the rotation of a rock-destroying working tool - a bit. The destroyed rock is removed from the well by drilling fluid, foam or gas injected into the pipe string and exiting through the annulus.

Rotary drilling

In rotary drilling, the bit rotates with the entire drill string; rotation is transmitted through the working tube from the rotor connected to the power plant by a transmission system. Weight on bit is created by a portion of the weight of the drill pipes.

In rotary drilling, the maximum torque of the string depends on the resistance of the rock to the rotation of the bit, the frictional resistance of the string and the rotating fluid against the borehole wall, as well as the inertial effect of elastic torsional vibrations.

In world drilling practice, the rotary method is the most common: almost 100% of the drilling work in the USA and Canada is performed by this method. In recent years, there has been a tendency to increase the volume of rotary drilling in Russia, even in the eastern regions. The main advantages of rotary drilling over turbine drilling are the independent control of drilling mode parameters, the possibility of triggering large pressure drops on the bit, a significant increase in penetration per bit run due to lower bit rotation frequencies, etc.

Turbine drilling

In turbine drilling, the bit is connected to the turbine shaft of a turbodrill, which is driven by the movement of fluid under pressure through a system of rotors and stators. The load is created by part of the weight of the drill pipes.

The greatest torque is due to the resistance of the rock to the rotation of the bit. The maximum torque determined by the calculation of the turbine (the value of its braking torque) does not depend on the depth of the well, the bit rotation frequency, the axial load on it, and the mechanical properties of the rocks being drilled. The power transfer coefficient from the energy source to the destructive tool in turbine drilling is higher than in rotary drilling.

However, with turbine drilling, it is impossible to independently control the parameters of the drilling mode, and at the same time, energy costs per 1 m of penetration, the cost of depreciation of turbodrills and the maintenance of workshops for their repair are high.

The turbine drilling method has become widespread in Russia thanks to the work of VNIIBT.

Drilling with screw (displacement) motors

The working bodies of the engines are based on a multi-thread screw mechanism, which makes it possible to obtain the required rotational speed at an increased torque compared to turbodrills.

Downhole motor consists of two sections - motor and spindle.

The working bodies of the motor section are the stator and the rotor, which are a screw mechanism. This section also includes a double joint. The stator is connected to the drill string by means of a sub. Torque is transmitted from the rotor to the output shaft of the spindle by means of a double-hinged connection.

The spindle section is designed to transfer the axial load to the bottomhole, absorb the hydraulic load acting on the motor rotor, and seal the lower part of the shaft, which contributes to the creation of a pressure drop.

In screw motors, the torque depends on the pressure drop across the motor. As the shaft is loaded, the torque developed by the engine increases, and the pressure drop in the engine also increases. The operating characteristic of a screw motor with the requirements for efficient bit mining makes it possible to obtain an engine with an output shaft speed of 80-120 rpm with increased torque. This feature of screw (displacement) engines makes them promising for implementation in drilling practice.

Drilling with an electric drill

When using electric drills, the rotation of the bit is carried out by an electric (three-phase) AC motor. Energy is supplied to it from the surface through a cable located inside the drill pipe string. The drilling fluid circulates in the same way as in the rotary drilling method. The cable is inserted into the pipe string through a current collector located above the swivel. The electric drill is attached to the lower end of the drill string, and the bit is attached to the shaft of the electric drill. The advantage of an electric motor over a hydraulic one is that the rotational speed, torque and other parameters of an electric drill do not depend on the amount of fluid supplied, its physical properties and the depth of the well, and in the possibility of controlling the engine operation process from the surface. The disadvantages include the difficulty of supplying energy to the motor, especially at elevated pressure, and the need to seal the motor from the drilling fluid.

Promising directions in the development of drilling methods in world practice

In domestic and foreign practice, research and development projects are being carried out.

work in the field of creating new drilling methods, technologies, equipment.

These include deepening in rocks using explosions, destruction of rocks using ultrasound, erosion, using a laser, vibration, etc.

Some of these methods have been developed and are used, albeit to a small extent, often at the experimental stage.

Hydromechanical the method of destruction of rocks during the deepening of wells is increasingly used in experimental and field conditions. S.S. Shavlovsky carried out a classification of water jets that can be used in well drilling. The classification is based on the developed pressure, the working length of the jets and the degree of their impact on rocks of various composition, cementation and strength, depending on the diameter of the nozzle, the initial pressure of the jet and water flow. The use of water jets allows, in comparison with mechanical methods, to increase the technical and economic indicators of drilling a well.

At the VII International Symposium (Canada, 1984) the results of work on the use of water jets in drilling were presented. Its capabilities are associated with continuous, pulsating or intermittent fluid supply, the presence or absence of abrasive material, and technical and technological features of the method.

erosional drilling provides deepening speeds 4-20 times greater than with rotary drilling (under similar conditions). This is due, first of all, to a significant increase in the power supplied to the bottom in comparison with other methods.

Its essence lies in the fact that an abrasive material - steel shot - is supplied to the bit of a special design along with the drilling fluid. The size of the granules is 0.42 - 0.48 mm, the concentration in the solution is 6%. Through the nozzles of the bit, this solution with shot is fed to the bottom at high speed and the bottom is destroyed. Two filters are installed in series in the drill string, designed to screen out and retain particles whose size does not allow them to pass through the nozzles of the bit.

One filter is above the bit and the other is below the kelly where cleaning can be done. Chemical treatment of drilling fluid with shot is more difficult than treatment of conventional fluid, especially at elevated temperatures.

The peculiarity is that it is necessary to keep the shot in suspension in solution and then generate this abrasive material.

After preliminary cleaning of the drilling fluid from gas and cuttings with the help of hydrocyclones, the shot is taken and stored in a wetted state. Then the solution is passed through fine hydrocyclones and a degasser and its lost parameters are restored by chemical treatment. Part of the drilling fluid is mixed with shot and fed into the well, mixing with conventional drilling fluid on the way (in the calculated ratio).

lasers- quantum generators of the optical range - one of the remarkable achievements of science and technology. They have found wide application in many fields of science and technology.

According to foreign data, it is currently possible to organize the production of continuous gas lasers with an output power of 100 kW and more. The coefficient of performance (COP) of gas lasers can reach 20 - 60%. The high power of lasers, provided that extremely high radiation densities are obtained, is sufficient to melt and vaporize any materials, including rocks. The rock also cracks and peels off.

The minimum power density of laser radiation sufficient for the destruction of rocks by melting was experimentally established: for sandstones, siltstones and clays, it is approximately 1.2-1.5 kW/cm 2 . The power density of the effective destruction of oil-saturated rocks due to thermal processes of oil combustion, especially when air or oxygen is blown into the destruction zone, is lower and amounts to 0.7 - 0.9 kW/cm 2 .

It has been calculated that for a well with a depth of 2000 m and a diameter of 20 cm, about 30 million kW of laser radiation energy must be expended. Drilling wells of such depth is not yet competitive in comparison with traditional mechanical drilling methods. However, there are theoretical prerequisites for increasing the efficiency of lasers: with an efficiency of 60%, energy and cost costs will significantly decrease and its competitiveness will increase. When using a laser in the case of drilling wells with a depth of 100 - 200 m, the cost of work is relatively low. But in all cases, during laser drilling, the cross-sectional shape can be programmed, and the borehole wall will be formed from a rock melt and will be a glassy mass, which makes it possible to increase the coefficient of drilling mud displacement by cement. In some cases, it is obviously possible to do without well casing.

Foreign firms offer several designs of lasers. They are based on a powerful laser placed in a sealed housing that can withstand high pressure. Thermal stability has not yet been studied. According to these designs, the laser radiation is transmitted to the bottomhole through a light-conducting fiber. As the rock is destroyed (melted), the laser drill moves down; it can be provided with a vibrator installed in the housing. When the projectile is pressed into the rock melt, the walls of the well can be compacted.

In Japan, the production of carbon dioxide gas lasers has begun, which, when used in drilling, will significantly (up to 10 times) increase the rate of penetration.

The wellbore cross section during wellbore formation by this method can have an arbitrary shape. The computer according to the developed program remotely sets the scanning mode of the laser beam, which allows you to program the size and shape of the wellbore.

Carrying out laser thermal work is possible in the future in perforation work. Laser perforation will provide controllability of the process of destruction of the casing string, cement stone and rock, and can also contribute to the penetration of channels to a considerable depth, which will certainly increase the degree of perfection of the formation. However, the melting of rocks, which is expedient when deepening the well, is unacceptable here, which should be taken into account when using this method in the future.

In domestic works, there are proposals for the creation of laser-plasma installations for thermal drilling of wells. However, transportation of plasma to the bottom of the well is still difficult, although research is underway on the possibility of developing light guides ("light guide tubes").

One of the most interesting methods of influencing rocks, which have the criterion of "universality", is the method of their melting by means of direct contact with a refractory tip - a penetrator. Significant progress in the creation of heat-resistant materials made it possible to transfer the issue of melting rocks to the field of real design. Already at a temperature of approximately 1200-1300 ° C, the melting method is workable.

soben in loose soils, sands and sandstones, basalts and other rocks of the crystalline basement. In rocks of the sedimentary complex, the penetration of clayey and carbonate rocks apparently requires a higher temperature.

The method of drilling by melting makes it possible to obtain a sufficiently thick glass-ceramic crust with smooth inner walls on the walls of the well. The method has a high coefficient of energy input into the rock - up to 80-90%. In this case, at least in principle, the problem of removing the melt from the bottom can be solved. Leaving through the outlet channels or simply flowing around a smooth penetrator, the melt, solidifying, forms a sludge, the size and shape of which can be controlled. The cuttings are carried by a fluid that circulates above the drill string and cools the top of the drill string.

The first projects and models of thermal drills appeared in the 60s, and the theory and practice of rock melting began to develop most actively from the mid-70s. The efficiency of the melting process is determined mainly by the temperature of the surface of the penetrator and the physical properties of rocks and depends little on the mechanical and strength properties. This circumstance determines a certain universality of the melting method in the sense of its applicability for sinking various rocks. The melting temperature range of these various polymineral multicomponent systems generally falls within the range of 1200-1500°C at atmospheric pressure. In contrast to the mechanical method of destruction of rocks by melting, with an increase in the depth and temperature of the underlying rocks, it increases its efficiency.

As already mentioned, in parallel with the penetration, the walls of the well are fastened and isolated as a result of the creation of an impermeable vitreous annular layer. It is not yet clear whether the wear of the surface layer of the penetrator will occur, what is its mechanism and intensity. It is possible that fusion drilling, although at a low rate, can be carried out continuously within the interval determined by the design of the well. This design itself, due to the continuous fastening of the walls, can be significantly simplified, even in difficult geological conditions.

One can imagine the technological procedures associated only with the fastening and insulation of the walls in series with the sinking of the shaft by the method of conventional mechanical drilling. These procedures can only apply to in-

intervals that are dangerous due to the possibility of various complications.

From the point of view of technical implementation, a current conduit to the injection elements of the penetrator should be provided, similarly to that used in electric drilling.

3. Classification of wells

Wells can be classified according to purpose, wellbore and filter profile, degree of refinement and filter design, number of casing strings, location on the surface of the earth, etc.

According to the purpose, wells are distinguished: reference, parametric, structural-search, exploration, oil, gas, geothermal, artesian, injection, observation, special.

According to the profile of the wellbore and the filter, the wells are: vertical, inclined, directionally oriented, horizontal.

According to the degree of perfection, wells are distinguished: super-perfect, perfect, imperfect in terms of the degree of opening of productive layers, imperfect in terms of the nature of opening of productive layers.

According to the design of the filter, wells are classified into: loose, fixed with a production string, fixed with a plug-in slotted or mesh filter, fixed with a gravel-sand filter.

According to the number of columns in the well, wells are distinguished: single-column (only production string), multi-column (two-, three-, p-columns).

According to the location on the surface of the earth, wells are distinguished: located on land, shelf, offshore.

The purpose of structural exploration wells is to establish (clarify) tectonics, stratigraphy, lithology of the rock section, and evaluate possible productive horizons.

Exploration wells are used to identify productive strata, as well as to delineate developed oil and gas fields.

Extractive (operational) are intended for the extraction of oil and gas from the earth's interior. This category also includes injection, appraisal, observation and piezometric wells.

Injectors are necessary for pumping water, gas or steam into the reservoir in order to maintain reservoir pressure or treat the bottomhole zone. These measures are aimed at lengthening the period of the flowing method of oil production or increasing the efficiency of production.

The purpose of appraisal wells is to determine the initial water and oil saturation and residual oil saturation of the formation and conduct other studies.

Control and observation wells are used to monitor the development object, study the nature of the movement of reservoir fluids and changes in gas-oil-saturation of the reservoir.

Reference wells are drilled to study the geological structure of large regions in order to establish the general patterns of occurrence of rocks and to identify the possibilities for the formation of oil and gas deposits in these rocks.

Test questions:

1. How are wells classified?

2. What are known well drilling methods?

3. What is laser drilling? ?

Literature

1. Bagramov R.A. Drilling machines and complexes: Proc. for universities. - M.: Nedra, 1988. - 501 p.

2. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Completion of wells: Proc. allowance for

universities. - M: LLC "Nedra-Business Center", 2000. - 670 p.

3. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Complications and accidents during oil drilling

and gas wells: Proc. for universities. - M.: Nedra-Businesscenter LLC, 2000. -679 p.

4. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Oil and gas drilling technology

Wells: Proc. for universities. - M.: Nedra-Businesscenter LLC, 2001. - 679 p.

5. Boldenko D.F., Boldenko F.D., Gnoevykh A.N. Screw downhole motors. - M.: Nedra,

Our civilization has reached today an unprecedented flourishing of science and technology, as a result of which we have a chance to enjoy all its benefits. However, this would not be possible without the extraction of the most important thing - its drilling of oil and gas wells today is the most important work that is carried out on a global scale in order to replenish the resources spent on the development of new technologies.

Today, geological exploration is subject to rather high requirements regarding the accuracy of determining the location of oil and gas, as well as calculating their estimated volume. This is due, first of all, to the rather high costs of installing high-tech equipment, where direct drilling of oil and gas wells is quite expensive. After all, when performing this work, there is always a big risk that the calculations could turn out to be erroneous, as a result of which the industrial investor company may suffer significant losses.

There are several ways to carry out drilling operations, but the most optimal and rational is which is also used in the exploration of minerals. It is also widely used in hydrogeological studies, structural mapping surveys and gas and oil fields. Thanks to drilling, exploration shafts and pits are also being created, thanks to which soils of various horizons can be extracted from the bowels of the earth to determine its origin and the possibility of using it for practical purposes.

Drilling of oil and gas wells begins with the preparation of the appropriate site, as well as the formation of convenient access roads. When installing a drilling station in the open sea, there is a special technology by which a floating station is designed, mounted directly above a gas or oil field, after which, using special fasteners, it is installed in the right place and begins to function. If the deposits are on a solid surface, then after the first stage and burying the tanks for the flushing liquid, they proceed to the direct collection of the oil or gas rig.

The schematic diagram of the drilling rig includes the following composite structures:

Tower directly;

drilling building;

Drilling mechanism;

Powerful internal combustion engine.

The technology of drilling oil and gas wells is the following scheme for the implementation of work: depending on the type of soil, the drill column, spindle and drill set the appropriate speed and a certain axial load. Rotating and gradually penetrating into the ground, the bit drills out the annular bottomhole and forms a core, which in turn fills the core barrel. With the help of special flushing liquids or process water, it is washed out and brought to the surface. All drilling of oil and gas wells is a well-organized cycle of work, in which the systems clearly interact with each other.

It is difficult to overestimate the importance of the global oil and gas industry, because without the main raw materials, the development of mechanical engineering, the chemical industry and metallurgical industry would simply be impossible. In the context of the gradual depletion of existing fields, drilling oil wells in new places is a very topical issue. We can be sure that in the coming decades we will witness the emergence of a new series of large drilling rigs that will continue to provide modern civilization with oil and gas.