Types of oil drilling. Well drilling - types of wells, general concepts of drilling. How to drill different types of soil

Borehole

(a. well, drilling hole; n. Bohrloch; f. trou de forage; And. agujero, pozo de sondeo) - horn. production of advantages round section (diameter 59-1000 mm), formed as a result of drilling. B. s. divided into small - deep. up to 2000 m (of which the vast majority - up to several hundreds of meters), medium - up to 4500 m, deep - up to 6000 m, ultra-deep - St. 6000 m. allocate the mouth, trunk and bottom (). According to the position of the axis of the trunk and B.'s configuration with. divided into vertical, horizontal, inclined; unbranched, branched; single and cluster. According to their purpose, they distinguish between research, intended for the study of the earth, operational (development, see Fig.) - for the development of deposits of p. and., construction - for the construction of decomp. structures (bridges, berths, pile foundations and foundations, underground storage facilities for liquids and gases, water conduits), mining engineering. B. s. - for the construction and operation of the horn. structures.
drilling fluid; 4 - cement stone; 5 - production string; 6 - productive; 7 - perforated holes; 8 - column head; 9 - valves; 10 - . ">
Development well design: 1 - guide string; 2 - conductor string; 3 - drilling fluid; 4 - cement stone; 5 - production string; 6 - productive formation; 7 - perforated holes; 8 - column head; 9 - valves; 10 - cross.
Research B. with. are divided into mapping, structural-exploratory, supporting-geological, supporting-technological, engineering-geological, parametric, prospecting and exploration. Operational B. s. according to the type of deposit being developed, they are divided into wells of oil, gas and water deposits ( cm. Oil well, Gas well, Hydrogeological well), according to the function performed - for producing, injection, appraisal, control (piezometric, observation), for operational. condition - for operating, under repair, inactive, mothballed and liquidated. Mining Engineering B. s. are divided into explosive (they account for the largest volumes of drilling - about 50 million m per year), freezing, plugging, ventilation, drainage, etc.
Depending on the depth and purpose of the bore hole, and the drilling conditions, the walls of the wells are fixed or left unfixed.
Barrel fastening is not made for mining. (eg, explosive) and other wells of small depth (up to 50 m) drilled in stable rock masses. B. with., intended for operation and research, are fixed in the process of construction. They have the most complex design, which is determined by the dimensions of the wellbore parts, casing strings and the cement sheath in the space behind the casing strings; type and number of casing strings; equipment for casing strings, wellheads and bottomholes B. s. Casing strings (guide, conductor, intermediate, and production) are designed to fasten the wall of parts of the barrel of the B. with. and isolation zones dec. complications, as well as the productive stratum from the rest of the geol. incision. Usually they are screwed (welded) from steel pipes; in small wells, casing pipes made of plastic and asbestos cement are used. The guide column (direction) is the first (up to 30 m long), which is lowered into the upper (guiding) part of the wellbore to isolate the upper alluvial soil and divert the upward flow of the drilling agent from the wellbore to the treatment system, is cemented along the entire length. Conductor string () - the second casing string, lowered into the wellbore of the B. with., is designed to cover the upper unstable deposits, aquifers and absorbing layers, permafrost zones, etc. Installed on it; the annular space behind the string is usually cemented along its entire length. An intermediate casing string is lowered, if necessary, after a surface casing for fixing unstable rocks, separating the zones of complications and aquifers. The depth of descent of the intermediate and conductor strings is calculated taking into account the prevention of hydraulic fracturing, the stability of the wall of the barrel of the B. with., the separation of the zones of application of decomp. drilling agents. The number of intermediate columns depends on the depth of B. with. and complexity of geol. incision. The last casing string is intended for production and isolates the productive formations. To extract fluids from reservoirs in production. the column is lowered by tubing strings in decomp. combinations depending on the number of reservoirs being developed and the production method used. In the intermediate and operational part of B.'s trunk with. instead of a full-length casing string, casing strings-liners can be lowered on drill pipes, the top of which is fastened with the help of special. pendants. The liner string after the completion of the construction of the well is sometimes increased to the mouth of the B. with. extension column.
To facilitate the descent, cementing of casing strings and improve the quality of these works, casing strings are equipped with guide shoes, decomp. valves, connect and disconnect. devices, cement turbulators, packers, centralizers and pigs. In multi-stage cementing, cementing sleeves are introduced into the casing string.
According to the number of casing strings lowered into the B.'s trunk with. after conductor, one-, two-, three- and multi-column well designs are distinguished; according to the type of equipment of the bottomhole zone - B. s. with cased and open bottomhole zone. B.'s design with. with a cased bottomhole zone can be obtained either by lowering into it a continuous exploitation. columns with its subsequent cementing and perforation of the column, cement stone and productive formation, or lowering into it an exploitation. strings with a tail section having round or slotted holes placed against the productive formation.
The design of gas wells is characterized by greater tightness of casing strings, which is achieved by using casing pipes with special compounds and lubricants for them, the rise of cement mortar behind all columns to the mouth of the B. with. etc. The mouths of development oil and gas wells are equipped with special equipment. fittings. The design of the B. with, intended for the search and exploration of deposits of solid deposits and., is much simpler. The directing part of such B. with. has a length of several m and is fixed with a guide pipe, the conductor part has a length. 30-150 m. Further, the shaft is drilled with complete core sampling, and the fastening of unstable rocks is carried out with quick-setting mixtures. Literature : cm. lit. at Art. Drilling. Ya. A. Gelfgat, D. E. Stolyarov.

Mountain Encyclopedia. - M.: Soviet Encyclopedia. Edited by E. A. Kozlovsky. 1984-1991 .

See what "Borehole" is in other dictionaries:

A borehole is a cylindrical excavation pierced by a drilling tool in the rock of the earth's crust, characterized by a large ratio of its length to diameter. The beginning of the well is called its mouth, the bottom is called the bottomhole, ... ... Wikipedia

See Drilling well ... Big Encyclopedic Dictionary

Lecture 1

First, let's define the terms:

« Borehole

wellhead "bottom hole"

Well axis - «

Well walls –

Wellbore - «

Well length - axes».

Well depth – vertically".

Well diameter

Well construction

well drilling

Well deepening

Drilling technology - «

.

900 mm to 26 mm.

Well depth up to 12260 m

Well length up to 13000

.

- Geologists - ;

in the exploration of hydrocarbons.

- ,

-

- Hydrogeologists – ,

- ,

- ,

-

-

History of MGRI - RGRU

In September 1918 the Moscow Mining Academy was created, in which exploration faculty, officially considered the ancestor MGRI-RGGRU.

IN 1930 year, the only one of its kind, the Moscow Geological Prospecting Institute, stood out from the MGA - MGRI, Thus, MGRI-RGGRU has two years of birth - 1918 and 1930.

Graduates of MGRI have always occupied a worthy place in the science and practice of geological exploration, hydrogeology, engineering geology and other sectors of the national economy.

1975 to 1989 Minister of Geology of the USSR was a graduate MGR specialty "Reconnaissance Technique" - RT-48 (second graduation) Evgeny Alexandrovich Kozlovsky.

Educational and scientific polygon MGRI

At the end of November 1935, the MGRI was transferred from the Moscow Electromechanical College a piece of land near the village of Ryazantsy, Zagorsky (now Sergiev Posad) district, Moscow region. The MGRI order read:

" §one. To improve the educational and practical work of students and conduct the main field training practices of students: geophysical, geodetic exploration And engineering and hydrogeological, as well as to organize an experimental training ground for training and research work as part of the NIS to conduct research experimental work.

Since that time, training practices for students of all major specialties have been constantly held at the site: geologists, hydrogeologists, geophysicists, exploration technicians, including training drilling practices.

Since 2010, an educational and historical museum of drilling equipment has been created at the Sergiev Posad test site.

Rice. 4. Fragment of the drilling museum

Lecture 2

Methods, types and varieties of drilling wells Table 1

Lecture 3

Rice. 6

The choice of the direction of the well is determined by the most complete solution of geological problems. The most accurate information about the reservoir rocks (structure, reservoir thickness) is obtained when the well crosses the reservoir in a cross strike, i.e. at an angle of 90º.

When drilling a well in complex geological sections, the behavior of its axis is significantly influenced by a number of factors, primarily geological (when moving from rocks of one hardness to rocks with another hardness, layering, fracturing, anisotropic properties of rocks, and others), as well as technical and technological ones. As a result, the wellbore is bent during drilling, and it is very difficult or even impossible to drill a straight well under such conditions. This curvature of the borehole axis is called natural. In these cases, it is advisable already in advance, taking into account the factors that cause curvature, to design a curved well path. At the same time, curvilinear routes are often not only easier to implement, but also more rational than straight ones.

Since it is necessary to use special technical means and technological methods to conduct a well along a given route, in this case the curvature of the well is called " artificial curvature”, and the work on the execution of such a route is called“ directional drilling»

Curvilinear routes, as well as rectilinear, can have any direction and differ "into curved with constant curvature, with variable curvature, with curvature in two directions, and combined combining straight and curved sections. (Fig. 7)

Along with multilateral wells, exploratory drilling uses multilateral drilling(incorrectly multilateral well), when several wells are sequentially passed from one site (due to rotation of the rotator of the machine) by one drilling rig at different angles (Fig. 9 a, b)

This solution gives a significant economic effect when drilling not very deep wells in hard-to-reach areas (Fig. 9 b) and deep oil and gas wells (Fig. 9 a), allowing saving on the laying of transport routes and site equipment, as well as reducing environmental damage.

The design of the well route is carried out in the following sequence:

1. Choice between single and multilateral wells. In this case, first of all, economic feasibility and the need to solve geological problems play a role. Environmental protection issues are beginning to play a particularly important role - with each transportation and installation of a drilling rig, serious damage is caused to nature - this must be taken into account.

2. If a single-lateral well is selected, its direction is determined: vertical, deviated, horizontal, rising. In terms of labor costs, they increase in the order in which the directions are (previously) named.

3. The next step is to determine the straightness or curvature of the well path. In the simplest geological sections (with monotonous bedding or in monolithic massifs), a straight line is usually chosen. In the case when, due to the action of geological and technological reasons, the well will deviate, it is more profitable to use natural curvature and design the well route to be curved. At the same time, it should be taken into account that with the increase in the intensity of the curvature of the well, the difficulties of its implementation also increase (power costs and the possibility of breakage of drill pipes increase). It is generally accepted that the intensity of curvature is not more than 0.05 deg/m. A curved route is also designed to solve certain problems and can be more efficient than a straight one. For example, when a well intersects steeply dipping formations, a straight inclined well should be laid with a large zenith angle, which creates technical difficulties, in addition, the length of such a well will be greater than that of a curved one (L1>L2) (Fig. 10).

In the practice of production drilling, curved wells are used, the end part of which, which is part of the reservoir, approaches the horizontal position and runs along the reservoir, which increases the possibility of extracting minerals (in oil drilling, such wells are called "horizontal", but it is more correct when they are called "well with horizontal ending - s.g.o."). (Fig. 12).

Rice. 13.

SSC shells differ from simple ones in that they consist of a string of special drill pipes having the same internal section as that of a core barrel. A thin-walled core pipe is placed in the core barrel, into which a core column enters during drilling (Fig. 13 c). drill pipe rises to the surface. Thus, instead of several hours for round-trip operations when drilling deep wells, it will take several tens of minutes to recover from a core well. Taking into account the fact that SSC shells are much more expensive than simple shells, it is more profitable to use simple shells for drilling shallow wells (up to about 200 - 300 meters), and for deeper wells it is more profitable to use SSK shells.

When drilling with shells with hydro or pneumatic core transport, a double string of drill pipes is used. The flow of the cleaning agent is fed to the bottom through the gap between the outer and inner pipes. At the bottom, the flow turns and rises up along the inner column, bringing core pieces or core material to the surface when drilling through clastic rocks. All 100% of the core (or core material) is brought to the surface simultaneously with the process of deepening the well. With this method of drilling, no additional time is spent on lifting the core, which allows a sharp increase in productivity. However, high productivity is possible only when drilling in soft and weak rocks, where the rock is easily destroyed and mechanically removed from the bottomhole into the inner pipe. The second limitation of the use of KGC, KPC is a relatively small depth of wells. Typically, well depths up to 500 meters are accepted. Greater depth can be achieved using blowdown in combination with annular hammers and high pressure compressors (up to 2.5 MPa).

The third option for choosing drilling types depending on geological conditions is associated with the use of drilling tools (simple or special) with an additional downhole mechanism or a special core set.

In special cases, the following may apply:

Mechanisms that create shock impulses to the rock cutting tool (DRD): a)) when drilling with flushing - hydraulic hammers, b) when drilling with a purge or drilling with foam - hammers;

- downhole screw hydraulic motor;

Special core sets for obtaining a conditioned core in difficult geological conditions.

Shock impulses to the bottomhole during rotary drilling are used to solve a number of problems:

Possibility to drill strictly straight vertical wells due to the fact that there is no need for an axial load on the drilling rig;

Increase the drilling speed due to additional percussive destruction of the rock, especially with pneumatic percussion drilling, where the speed can increase by 2-3 times (when drilling with hydraulic percussion drilling, the speed increases slightly);

With high-frequency hydraulic percussion drilling, the friction of the cutters on the rock and the core in the core barrel is significantly reduced. This allows you to deal with the polishing of diamond crowns and core self-jamming in the column pipe.

Downhole screw hydraulic motor small diameter can be used in drilling both exploration and exploration oil and gas wells.

A feature of the use of downhole motors is that the drill pipe string does not rotate during drilling, but only the rock cutting tool rotates - a chisel or core barrel with a crown. When drilling oil and gas wells, downhole motors are used very widely. When drilling exploration wells of small diameter, the power of the downhole motor is insufficient for efficient drilling. However, the ability to drill without rotation of the downhole motor tubing string is successfully used for directional drilling, when the well route needs to be deviated to the right side at the right angle. The downhole motor included in the projectile on the "curved adapter" allows you to qualitatively control the direction of the well route.

Special core sets for obtaining conditioned core in unfavorable geological conditions (eroded, crumbling, layered, fractured, destroyed, crushed, intermittent, etc. rocks). Due to special designs or due to special technology (reverse circulation of flushing fluid), such core sets protect the core from destruction due to erosion, rotation of the core barrel, destruction of the bit by cutters. Since obtaining a full-fledged core is of paramount importance for geologists, this issue will be considered in detail in practical classes.

Lecture 6

Rice. fourteen

6. In addition to the graphic image, the design of the well is determined by its code and an explanatory note with the rationale for its parameters. Of the published methods for compiling a code for the design of geological exploration wells, the most complete and accurate is the method proposed by the Donetsk PTI.

Well design example ( in Fig. 15) in cipher.

Rice. 15

C(20) 112/108cp(220), 93/89cp(440.. .480), 76(1000)

The main notation of the cipher:

132 - figure indicating the diameter of drilling

/ - a sign indicating pipe fastening

127 - the figure behind the sign / indicates the diameter of the casing,

(20) - the figure in parentheses after the size of the casing indicates the depth to which the well is cased

(440….480) - countersunk column installation interval

Additional cipher designations:

C - a sign of cementing the entire column. It is placed behind the diameter of the casing pipes.

Cb - a sign of cementing only the shoe (lower part) of the column

Tsp - a sign of cementing the shoe and the upper end of the hidden casing string

; - sign of well expansion. Placed before the designation of the diameter of the tool that reams the hole

Symbol applicable to stepped casing strings

" - designation of the casing string to be retrieved. It is placed before the designation of the diameter of the casing string, after which the length of a part of the string can be indicated in brackets if it is not completely extracted.

The above designations cover the entire range of parameters included in the usual concept of well design or depicted on the design diagrams. However, if necessary, you can enter any other additional letter indexes.

In this example: - the hole is drilled with a bit Ø 132 mm and secured with a guide pipe Ø 127 mm up to a depth of 20 m. Here pipes Ø 127 mm are cemented to the full length. Further, the drilling diameter was 112 mm to 220 m, and the well was fixed to this depth with a conductor Ø 108 mm. For a column with a diameter of 108 mm, only the shoe (lower part of the column) is cemented. Further drilling is carried out with a bit Ø 93 mm to a depth of 480 m. In the range from 440 to 480 m, the complication zone and the wellbore are fixed with a hidden column Ø 89 mm (the shoe and the upper part are fixed with cement at the hidden column). Up to a depth of 1000 m, the well has a diameter of 76mm without fixing.

Rice. 16

Rice. 17

Another feature of the construction of oil and gas wells is the critical importance of isolating horizons in order to prevent fluid flow from different horizons. Almost all casing strings are isolated by cementing the annulus. Since when drilling oil and gas wells, it is necessary to isolate formations with fluids of various compositions, including aggressive ones that are dangerous when they enter productive formations and at different pressures, cementing the annulus of casing strings is of paramount importance. Great importance is attached to the composition and quality of cement mixtures, their properties and parameters. Particular importance is attached to quality control of cementing. Therefore, geophysical methods of cementing quality control are given paramount importance. In practice, to study the technical condition of the well, the method of radioactive isotopes, the acoustic method, the method of well thermometry are used. These methods determine the height of the cement slurry in the annulus, identify the places of annular circulation, the state of contact of cement stone with casing pipes and rock in the walls of the well.

Fig.18

Lecture 1

What is a borehole and what is well drilling.

First, let's define the terms:

« Borehole - a cylindrical hole (mining) in earth's crust, ice massifs and in artificial structures, which is much larger in length than its diameter.

The beginning of the well is called - " wellhead ”, the bottom of the well (the surface of the bottom of the well) and in the process of deepening (drilling) and at the end of the deepening is called "bottom hole"

Well axis - « line connecting the centers of the cross sections of the well from the mouth to the bottom.

Well walls – "lateral surface of the well".

Wellbore - « the inner part of the well, limited by its walls.

Well length - "the distance between the wellhead and the bottom of the well along its axes».

Well depth – "distance between the mouth and the bottom of the well vertically".

Well diameter – “nominal borehole diameter equal to the diameter of the rock cutting tool

Note - The actual diameter of the well in different areas may be larger due to drilling and development of the wellbore, or smaller due to rock swelling.

Well construction - (well construction), Performance of the whole complex of works, starting with site preparation and installation of the drilling rig and ending with the reclamation of the territory after drilling, as a result of which the well was drilled, the results were obtained, and the well was liquidated or closed.

well drilling - performance of a complex of works, from drilling to the end of deepening upon reaching the final depth and completion of all work in the well.

Well deepening - the drilling process, in which the destruction of the rock at the bottom of the well and the progressive movement of the bottom.

Drilling technology - « a number of successive choices and decisions that ensure the effective implementation of the process, including the choice of technical means and methods for performing the process". In a narrower sense, technology refers to choice of methods and process control parameters drilling. This narrow sense closely corresponds to the concept of drilling mode.

Technical means for drilling wells - drilling equipment, drilling tools, instrumentation (CIP), automation and control tools (CA and CS).

What is a borehole.

The well can be drilled not only down, but also obliquely and horizontally, and even up.

The axis of the well can be rectilinear and curvilinear; (fig.3)

The wellbore diameter can change in steps (Fig. 1)

Well diameters can vary from 900 mm to 26 mm.

Well depth up to 12260 m. (scientific Kola superdeep).

Well length up to 13000 m. (oil well on Sakhalin Island).

What is the connection between drilling wells and geologists and hydrogeologists .

- Geologists - obtaining complete and reliable geological information;

In the exploration of solid minerals,

in the exploration of hydrocarbons.

- determination and calculation of mineral reserves,

- compilation of geological maps and sections.

- Hydrogeologists – carrying out engineering and geological research,

- obtaining hydrogeological information,

- design of water intake and observation wells,

- development of water wells.

- design and development of drainage wells.

Drilling is the process by which the construction of a cylindrical mine working (well, hole) is carried out due to the destruction of rocks. Most often, drilling is carried out in the earth's crust. Less common in concrete and asphalt. Drilling is used to search, study and extract minerals; blasting operations; drainage of wetlands; laying of underground communications; construction of pile foundations. There is a special classification of drilling methods. The first classification is according to the nature of the destruction of rocks. They are divided into mechanical and non-mechanical. The first type is the destructive effect of the drilling tool on the rock. The second type - destructive impact occurs without contact of the impact source with the rock. Mechanical drilling, in turn, is divided into rotary, percussion, rotary percussion and rotary percussion. Rotary drilling destroys the rock by rotating a tool pressed against the bottomhole. For this type, most often, a cutting type tool (rock breaking), diamond tool, shot drilling and shot cores are used. The choice of tool type depends on the strength of the rock. Percussion methods include percussive drilling and percussive rotary (drilling with perforators). Also, drilling can be divided according to the type of tool with which drilling is performed. From this classification, one can distinguish screw, diamond, cone and rod.

There is a subdivision according to the types of drilling machines (turbine, pneumatic percussion, perforating) and according to the method of conducting wells (cluster and inclined).

Drilling under development and specialization is mainly applied to three fundamental areas of technology. The first area is drilling for oil and gas. To do this, deep enough wells are drilled, several kilometers deep.

The second area is wells reaching a depth of hundreds of meters. Such wells are drilled in the search for solid minerals. The latter area is used in construction and mining for laying explosives in rocks. The depth of such wells varies from a few meters to tens of meters.
Drilling for water is the most crucial stage when the issue of water disposal and water supply for a house or a summer residence is solved. It is customary to start the water supply of a summer house or a house with a choice regarding the source of water. This is usually done by the owner himself. In order to perform the following drilling steps, special equipment and experienced personnel are required. Water well drilling is a high-tech type of construction services. This requires high professionalism of the performer. The most reliable source of water supply today can be considered an artesian well. Since it is not possible to find identical cuts, the water drilling process is associated with many random factors. And the influence of the human factor in this area is very high.

All companies - professionals in the market and specialized organizations for drilling wells under water should have detailed and complete information about drilling methods and local geological conditions. They must submit projects that will indicate very precisely the projected depths and other characteristics of the wells and water quality.

In this work, the most important thing is that the geological specificity of the area and the specific place where the work on drilling water wells is going to strictly correspond to the level of the technical base used. Installations associated with the need for equipment and equipment for well installation work are selected taking into account the depth of occurrence and other parameters of the water-resistant and aquifer layers.

When arranging wells for water, it is important not to drill itself, but also to select and install a borehole pump. Control automation and plumbing systems are also used, passing from wells to summer cottages or houses. In our Everyday life the water supply system provides us with comfort. It's hard to imagine what we would do without her. The quality, reliability and reliability of water supply equipment today is at its best. And all this thanks to advanced pumps and automatic control. In order to drill a well under water, it is necessary to open limestone horizons. This type of drilling is called limestone drilling.

There is a sand well under the water. The advantages of such a well are low cost, ease of maintenance, quick installation and no need for registration and licensing of wells. All the necessary water is located at great depths and special pumps for wells are used to raise it from this depth. Trenchless technologies are used for laying a pipeline made of polyethylene or steel. Such technologies include inclined drilling, under-road puncture and HDD punctures. If you have not yet contacted the drilling of wells under water, you may be wondering why they are needed at all. They are needed in order to organize an individual water supply system for a house or cottage. You will get independence from all centralized water supply systems, incorrectly working automation and the eternal problem of pipeline corrosion. For the proper operation of the heating and sewerage of your home, as well as for the convenience of living, it is imperative to organize your own water well.

In order to choose the right well, you need to fully study the needs of residents and the purpose of using the well. a significant role plays the place for which the well is being drilled. It can be a large house with water consumption or a small house with a garden plot.

Depending on the quality of the water supply, the budget, and the volume of water consumption, one can distinguish some types of water well drilling. Drilling on the horizon of small filtered grains of sand (drilling wells for sand) is carried out to a depth of 30 meters. More precisely, until the sandy horizon is reached. After that, a well is usually installed, the diameter of which is from 126 millimeters to 134 millimeters. The inner diameter of the pipe of this well reaches from 126 millimeters to 134 millimeters. This pipe consists of a pipe called casing and throughput which is up to 20 liters per minute.

Most often, drilling a well in sand takes about two working days. If you decide to drill a well and value for money for the water supply system of a site with low water consumption, then a shallow sand well is best for you. Also, it is suitable for a summer residence or a house in which you live only in the summer or spring - autumn. Like all other wells, a sand well has its drawbacks. The main disadvantage of such a well is a very high probability of being flooded. The life of the pipes depends on how often the well is used and on the natural potential of the horizon. In addition to drilling wells for sand, there is drilling for limestone (artesian well). It consists in drilling wells to a depth of 20 meters to 210 meters to the aquifer. Drilling is carried out to limestone layers. Limestone wells are distinguished from other wells by their high productivity, which reaches up to 100 cubic meters per hour. Also, such wells can "boast" of high reliability.

As for the depth of limestone wells, it is much greater than the depth of sand wells. But because of this, the complexity of the work increases. It usually takes about three days to drill an artesian well. If you are going to live in a house or cottage all year round, then this type of water well will suit you best. It will help you always have crystal clear water in your house. Among the main advantages of such a well, the following can be distinguished: a large supply of water, a significant operational period due to the stability of aquifers of limestone slabs. While drilling an artesian well, its walls are strengthened. This helps the well serve you for 35 to 55 years. The disadvantage of such drilling is the need for additional equipment for water that is supplied to the well. After drilling, it is important to choose the right water treatment system. If you have installed an artesian well, then be sure that your home will always have clean drinking water for many years. Usually, wells are drilled before the construction of the house. This will save you money and your own energy. It also significantly affects the convenience in building a house, because you will need a lot of water.

Before you start drilling, you also need to take a very responsible approach to the placement of all objects on the site. If, after all, a summer house or a house was built before the organization of water supply, then there is nothing wrong with that. With the help of experienced specialists, drilling of wells can be done at any time during the construction of a house. In order to do all the drilling work correctly, you need professional technical equipment that allows you to perform work of absolutely different complexity and in all weather conditions. In principle, such work can be carried out at any time of the year. Winter time is favorable for the customer in that rather heavy and powerful machines will not spoil the site. Also, slag, which is brought to the surface during drilling, does not clog the territory of the building.

In advance, before choosing a place for drilling a well for water, you need to accurately measure 15 meters from the septic tank. If the slope of the terrain on the territory of the building is made towards the well, then the distance to the septic tank must be increased to 20 meters. The distance from the foundation or fence to the well should be taken no closer than three meters. The drilling method is selected depending on the structure of the soil, and the working area should be 24 cubic meters.
Since a water well can be called a capital structure, the area in which water drilling will be carried out must be very carefully selected. It should be located above the aquifer, which is favorable for the subsequent operation of the well. Also, the territory of the building must be adapted for repair work. The place where the well will be located must be distinguished by the relevant environmental standards and be protected from pollution. But we must remember that not every well has the ability to be water-bearing. Therefore, it is necessary to approach the calculations of the location of the future well with great responsibility before starting drilling. Important points in drilling are: determining the type of soil, checking the territory for the presence of vegetation, analyzing the surface of the site. This analysis includes topography, finding a suitable location for the well, a thorough check for harmful sources of pollution and the presence of water on the surface, studying the conditions that are below the surface of the site.
To determine the area of ​​drilling a well for water, a highly qualified specialist leaves for the place where the work is supposed to be carried out. He discusses with the customer the location of the future well, checks the availability of electricity at the site and selects a place for specialized equipment, accommodation for workers, a water carrier and a drilling rig. The next step, after drilling a well for water, is the arrangement of the well itself. The purpose of arranging a well is to supply water from the well itself to the surface of the site using a special pump. The pressure of this pump should raise the water to the surface. Drilling wells for water requires the establishment of a caisson. It is thanks to him that the customer will be able to consume pure drinking water in any season. The caisson is a metal tank that prevents water from freezing in winter. It also serves as an excellent protector against groundwater and other contaminants. Pipelines are laid from the caisson, which are suitable for a summer house or a house. They are laid at a depth of 1.9 meters.

Well drilling includes the installation of an automatic uninterrupted pump control system and a variety of filters for cleaning water from unnecessary impurities.

Well, the very last, concluding, stage in drilling wells for water is the chemical analysis of water. To do this, after all the drilling work done, a water sample is taken from the well and a chemical analysis is carried out. This analysis allows you to determine whether the water is suitable for daily use and for the normal operation of plumbing and household appliances. After all, if the water is not suitable and will have pollution and impurities, it will not only lead to breakdown of plumbing, but will also cause great damage to the human body.

Well, at the end of the drilling work, it remains only to equip it with the help of a casing string. The casing string is a structure that consists of pipes. Between themselves, these pipes are connected using a threaded method. More precisely, this thread is called a conical trapezoidal thread. Depending on the types of work, ordinary welding is also used to equip casing strings. If you have completed all the stages associated with drilling wells for water, including its arrangement, then it is safe to say that the work has come to an end and now you can enjoy your personal water supply. If you did these works at your summer cottage, where you appear only at a certain time, then naturally the well will not be in working order for a long time. After a long break (a year or more), the well must be checked. Most likely, after checking the well, it will need to restore the productivity of the aquifer and clean it up. Cleaning consists in flushing the bottomhole zone with a water-air mixture, cleaning the filter, and it is also possible to replace the casing strings.

Drilling wells for water in Perm includes the steps listed above. Experienced specialists will help you in choosing a place of work and calculations that are needed for the proper operation of water supply.

Drilling is the construction of a well, as well as the destruction of layers of the earth, followed by the extraction of destruction products to the surface

Drilling: for water, types of drilling, types of drilling, gas

Drilling is

Drilling is well construction, as well as destruction of earth layers with subsequent extraction of destruction products to the surface.

— process destruction of rocks with the help of special equipment - drilling equipment.

There are three types drilling:

Vertical drilling

Directional drilling

Horizontal drilling

Well drilling is process structures of directional cylindrical mining in the ground, the diameter "D" of which is small compared to its length along the shaft "H", without human access to the face. The beginning of the well on the surface of the earth is called the mouth, the bottom is called the bottom, and the walls of the well form its trunk.

Types of water wells

1. Filter well for water in sandy horizons.

To identify the presence of an aquifer in sandy soils, exploratory drilling is first performed.

When drilling an exploration well, there can be 3 situations:

1) The presence of water for the construction of a well for water, in the presence of a layer of water-saturated sand with a thickness of > 0.8 m.

2) The presence of water for the construction of a well - when interbedding a water-saturated sand and other types of clay soils.

3) Absence of aquifers.

Drilling of an exploratory well for water is usually carried out to a depth of 13-15 meters. The cost of exploratory drilling is 1000 rubles/meter. When in the course of exploratory drilling of aquifers for the construction of a well for water, price meters of exploratory drilling is included in price meters of drilling a well for water.

If an aquifer is found, a production well with a filter and a casing is drilled on it for the construction of a well. The depth of such a well is usually 13-25 m. sand produced by a combined screw and shock-rope method. When drilling, metal pipes with a threaded connection type, 168 mm in diameter, are used as an external casing string (to hold the walls of the well during drilling). After installing the production casing string with the filter inside the outer casing pipes, the outer pipes are removed.

The production casing string of a sand well consists of three parts:

1. Working column - located from ground level to the level of the aquifer. On the one hand, the pipes of the working string “casing” the well, keeping its walls from collapsing, on the other hand, they serve to place water-lifting pipes and a pump in them.

2. Filter column - a continuation of the working column, a perforated pipe equipped with a stainless steel wire mesh (0.2 - 0.315 mm).

Through the filter column from the thickness of water-saturated sand, water enters the well, and the mesh filter prevents sand particles from entering.

3. Accumulator - a blind pipe, closed from below with a plug, which serves for uninterrupted water supply (water supply).

2. Borehole to an aquifer in Ordovician limestones.

A limestone well is drilled into an aquifer that lies in limestone cracks. Limestone - rock, predominantly composed of calcite (calcium carbonate). Drilling of wells into aquifers in limestone is carried out with augers, which in appearance represent the working part of a corkscrew.

Unlike a sand well for water, the drilling process is less labor-intensive. When drilling a well for water, casing with external metal pipes is not required, to hold the walls of the well - due to the hardness of limestone. The depth of such a well is usually 15-40 m.

The well for “limestone” consists of three parts:

1. Working column.

2. The filter column is simply a perforated pipe (perforated filter).

3. The storage tank is a blind pipe.

3. Artesian wells for water supply to the Cambrian-Ordovician, Lomonosov aquifers and the Vendian aquifer (Gdov horizon).

Artesian aquifers, in our region, are confined to deep-lying sandstones, which are covered from above with layers of impermeable rock (clay strata) that form a barrier to the waters of Quaternary deposits. The water contained in the caverns of these sandstones is under great pressure at depth. When such an aquifer is opened by a well, the water level under pressure rushes to the surface of the earth and is usually set at a depth of 5-15 meters.

The first artesian wells, from which water burst out under its own pressure, were drilled in France, in the province of Artois, hence the name "Artesian well".

Such wells have a flow rate of approximately 2-15 m3 / h and have a depth of 80 m. They are drilled for water supply to enterprises, cottage settlements or detached residential buildings.

Drilling of artesian wells is carried out if the customer has a license for the right to use a subsoil plot for the purpose of geological study.

Percussion drilling method

The impact projectile is suspended on a rope, which is fed from an instrumental drum. During chiselling, the projectile is lifted and dropped with the help of a balancer - a retraction mechanism of the machine, or from a winch. When dropped, the projectile falls down under its own weight, destroying the rock at the bottom. As the well deepens, the drill line is etched from the tool drum, carrying out the bit feed. Having drilled a certain interval of the well, they stop chiselling and start cleaning the bottom hole. This operation is performed with a bailer. After cleaning the well, chiselling is continued or the well is started to be fixed - unstable intervals are fixed with casing pipes.

Drilling is

The drilling tool for UKB consists of a chisel, a shock rod, shears (jars) and a rope lock (ropsocket).

The following types of bits are used: flat, I-beam, z, rounding, cross, pyramidal and eccentric. The type of bit is determined by the nature of the rocks being penetrated. The angle of sharpening (attack) depends on the hardness of the drilled rocks.

In percussive drilling of alluvial deposits, for driving a leading casing string simultaneously with a deep well, a driving half-rod and an impact head are additionally used as part of the projectile.

Drilling is

To remove the destroyed rock from the bottom and when sinking quicksand layers, a bailer projectile is used in the following composition: a bailer, scissors and a rope lock. Sometimes a short shock bar (half bar) is added.

A bailer with a flat valve and a driving glass.

a) flat; b) I-beam; c) rounding; d) cross

The main advantage of the shock-rope method is that - it is not required to supply drilling rigs with clay and water.

The main disadvantage is the low mechanical speed in easily passable rocks, the relatively high cost of casing pipes, the method is more energy-intensive. Also, when drilling in rocks above category III in the immediate vicinity of buildings, damage to the foundations from the resulting vibration when the bit hits the bottom is possible.

Rotary drilling

It has several main directions: auger, core, drilling with direct and reverse flushing, drilling with a purge.

With the auger method of drilling soft and loose rocks, the destruction of the rock at the bottomhole is carried out by a rotating bit of various designs, the destroyed rock is transported from the bottomhole to the day surface by augers, which are a single screw conveyor. When auger drilling with an annular slaughter, magazine augers and special crowns are used. This type of drilling is the most common and most versatile of all types of shallow drilling. It is used when drilling in rocks from I to VI categories in terms of drillability, including gravel-pebble and rocks with the inclusion of small boulders. Auger drilling is widespread due to the fact that during drilling in most rocks, the walls of the well are simultaneously fixed by the rock being lifted.

Auger drilling process

The main advantage of drilling with augers is the high penetration rate.

The main disadvantage is the high energy consumption, the curvature of the wellbore, it is impossible to drill in rocks higher than category VI.

Drilling is

core drilling

During core drilling, the destruction of rock at the bottomhole is carried out by cutting an annular channel by rotating the core barrel with a drill bit placed at its end. In this case, in the central part of the bottomhole (inside the core barrel), a core is formed in the form of a column (monolith) of an undisturbed structure. After the formation of a core of sufficient length, it is torn off from the massif using a core extractor installed on the core barrel immediately above the bit and lifted to the surface. Often, core drilling of rocks is carried out with bottom-hole circulation of flushing fluid, less often with flushing the wellbore with mud. Instead of flushing, the face is also blown with compressed air. Purging has a number of important advantages over flushing, from the point of view of exploration drilling, namely:

Drilling is

Additional moisture is excluded, as well as erosion of the core and bottomhole;

The possibility of contamination and moistening of the sludge, as well as the mixing of sludge differences taken from different horizons is excluded.

And of course, such an important item as the delivery of water to wells is excluded.

core barrel

The main disadvantage that prevents the wide use of this method is the geological and hydrogeological limitation of the possibility of drilling: bottomhole blowing is most expedient and efficient in wells that do not contain water in a liquid state.

The main advantage is the high penetration rate in rocks from category V and above. Possibility of extraction to the surface of the core with undisturbed structure.

Wash drilling.

More than 85% of the total drilling of wells for water is carried out in a rotary way with washing with technical water or clay solution. Water, clay solutions treated with nonionic surfactants (OP-7, OP-10, etc.), water-hypan (3-5%) and carbonate solutions are used as a flushing liquid when opening aquifers. When drilling in a rotary way, two types of flushing are used: direct and reverse.

Drilling is

With direct flushing, the flushing fluid is supplied to the rock cutting tool through drill pipes and rises to the surface along the annular gap between the drill pipes and the walls of the well, carrying pieces of destroyed rock (sludge) with it.

During backwashing, the flushing fluid enters the well through a hermetically sealed wellhead along the wellbore and rises through the drill pipes to the surface.

Well flushing scheme

a - straight line; b - reverse; 1 - well walls; 2 - guide pipe; 3 - drill pipe; 4 - stuffing box; 5 - removal of flushing liquid; 6 - cover; 7 - supply of flushing liquid; 8 - adapter.

Solid-hole drilling is carried out with cone bits, the type of which is selected based on the category of rock to be drilled.

Annular bottomhole drilling with direct flushing is carried out using core sets with carbide or diamond core bits.

Main advantages. The speed of drilling by this method in rocks of soft and medium hardness at any depth is approximately 3 times higher compared to the shock-rope method. The design of a rotary drilling well is much simpler, and cost casing pipes are 40-60% less than in percussion drilling. Significantly lower energy consumption and energy consumption compared to other methods.

The main disadvantage is the provision of drilling rigs with water and clay.

Purge drilling.

In direct blow drilling, the processes in in general terms same as for direct flush drilling. Only instead of the solution, compressed air is supplied through the stuffing box swivel. And the destroyed rock (sludge) is blown to the surface. Drilling is carried out with pneumatic hammers, as well as cone bits or core barrels with diamond or carbide crowns.

Drilling is

Well location

Since the well performs other functions than wells, it makes no sense to look for upstream water during work, to determine the optimal place. Customers, or if you are drilling for yourself, I can choose a site for a well on my own, in the place where it is convenient and will have the best effect.

This is all the more effective for the reason that there is water in almost any soil, the only question is how deep it is. Drilling rigs drill wells up to 50 meters, which gives an almost guaranteed result.

How to drill different types of soil?

The question is by no means idle, since there are significant differences in the technology of breaking through clay or stony soils. Don't forget. that at different depths the type of soil can change, this should be taken into account and change the equipment and nozzles.

The most time-consuming, slow and expensive drilling process is the development of calcareous, hard and stony interlayers and soil types.

A typical mistake of beginners is that in an effort to quickly go through an unpleasant section, the speed increases, which is why the drill “bites” and Job stops at all. On the contrary, the speed of the drilling equipment should be 30-40, then you will steadily go through a difficult section.

You will be able to break through the strong and hard ground much easier. If you are using a cone bit, a cone with a rectangular band thread.

Unfortunately, there are simply impassable areas - huge stones hidden in the thickness of the earth. In this case, it is recommended to rearrange the installation.

Clay soils are a driller's paradise; the drill breaks through such soil easily and quickly. everything goes like clockwork, moreover, nothing threatens the well, clay areas are not subject to delamination and shedding.

Sandy soils, quicksand.

Actually, it is in the sand that underground water, springs, and aquifers are located.

However, the top layer, quicksand, is not suitable for exploitation, so such sand layers are also passed. The biggest difficulty is that the sand crumbles, can fill up and ruin all the work. To avoid this, special additives are added to the recycled water - clays (natural, dry and bentonite), stuvamax.

The most important thing is not to rush and carefully monitor the behavior of the drilling rig.

In particular, water must always flow from the wellbore. If not, then you need to raise the column of rods and use a motor pump. Raise the columns when extending the rods. Run air columns over the booms to clear tools.

Oil and gas wells

According to the method of impact on rocks, mechanical and non-mechanical drilling are distinguished. In mechanical drilling, the drilling tool directly affects the rock, destroying it, and in non-mechanical drilling, the destruction occurs without direct contact with the rock from the source of impact on it. Non-mechanical methods (hydraulic, thermal, electrophysical) are under development and are not currently used for drilling oil and gas wells.

Mechanical drilling methods are divided into percussion and rotary.

During impact drilling, the destruction of rocks is carried out by a bit 1 suspended on a rope (Fig. 3). The drilling tool also includes a shock rod 2 and a rope lock 3. It is suspended on a rope 4, which is thrown over a block 5 mounted on a mast (not shown conventionally). The reciprocating motion of the drilling tool is provided by the drilling machine 6.

1 - chisel; 2 - shock rod; 3 - rope lock; 4 - rope; 5 - block; 6 - drilling machine.

As the well deepens, the rope is lengthened. The cylindricity of the well is ensured by turning the bit during work.

To clean the bottom from the destroyed rock, the drilling tool is periodically removed from the well, and a bailer is lowered into it, similar to a long bucket with a valve in the bottom. When the bailer is immersed in a mixture of liquid (formation or poured from above) and drilled rock particles, the valve opens and the bailer is filled with this mixture. When the bailer is raised, the valve closes and the mixture is taken up.

Upon completion of bottomhole cleaning, the drilling tool is lowered into the well again and drilling continues.

In order to avoid the collapse of the walls of the well, a casing pipe is lowered into it, the length of which is increased as the bottomhole deepens.

Currently, when drilling oil and gas wells, impact drilling is not used in our country.

Oil and gas wells are constructed using the rotary drilling method. With this method, the rocks are not crushed by impacts, but are destroyed by a rotating bit, which is subjected to an axial load. The torque is transmitted to the bit or from the surface from the rotator (rotor) through the drill string (rotary drilling) or from the downhole motor (turbodrill, electric drill, screw motor) installed directly above the bit.

Drilling is

A turbodrill is a hydraulic turbine driven by a drilling fluid injected into the well. An electric drill is a liquid-proof electric motor powered by a cable from the surface. A screw motor is a kind of downhole hydraulic machine in which a screw mechanism is used to convert the energy of the flushing fluid flow into mechanical energy of rotational motion.

According to the nature of the destruction of rocks at the bottom, continuous and core drilling are distinguished. With continuous drilling, the destruction of rocks is carried out over the entire area of ​​the face. Core drilling provides for the destruction of rocks only along the ring in order to extract a core - a cylindrical sample of rocks along the entire or part of the length of the well. With the help of core sampling, the properties, composition and structure of rocks, as well as the composition and properties of the fluid saturating the rock, are studied.

All drill bits are classified into three types:

bits of cutting and shearing action, destroying the rock with blades (blade bits);

bits of crushing and shearing action, destroying the rock with teeth located on cones (cone bits);

bits of cutting-abrasive action, destroying the rock with diamond grains or hard-alloy pins, which are located in the end part of the bit (diamond and hard-alloy bits).

Drilling rig: 1 - bit; 2 - bit collared drill pipe; 3 - sub; 4 - centralizer; 5 - sleeve sub; 6, 7 - drill collars; 8 - sub; 9 - safety ring; 10 - drill pipes; 11 - safety sub; 12, 14 - lower and upper rod subs; 13 - leading pipe; 15 - swivel sub; 16 - swivel; 17 - riser; 18 - hose; 19 - hook; 20 - traveling block; 21 - tower; 22 - crown block; 23 - gearbox; 24 - winch; 25 - rotor; 26 - sludge separator; 27 - drilling pump

Systematization of oil and gas wells according to their purpose

Wells for oil and gas can be systematized as follows:

structural and prospecting, the purpose of which is to establish (clarify tectonics, stratigraphy, lithology, estimate the productivity of horizons) without additional well construction;

exploration, which serve to identify productive objects, as well as to delineate already developed oil and gas reservoirs;

production (operational), intended for the extraction of oil and gas from terrestrial bowels. This category also includes injection, appraisal, observation and parametric wells;

injection, designed for injection of water, gas or steam into the formations in order to maintain the formation pressure or treat the near-wellbore zone. These measures are aimed at lengthening the period of the fountain method oil production or improving production efficiency;

leading mining, serving for oil production and gas with simultaneous refinement of the structure of the productive formation;

appraisal, the purpose of which is to determine the initial oil and water saturation and residual oil saturation of the reservoir (and other studies);

control and observation, designed to monitor the development object of the study of the nature of the movement of reservoir fluids and changes in the gas-oil saturation of the reservoir;

reference wells are drilled to study the geological structure of large regions, to establish the general patterns of occurrence of rocks and to identify the possibility of formation of deposits in these rocks black gold and gas.

Drilling is

Well construction cycle

The well construction cycle includes:

preparatory work;

installation of the tower and equipment;

preparation for drilling;

drilling process;

fixing the well with casing pipes and its grouting;

reservoir penetration and flow test black gold and gas.

In the course of the preparatory work, a place is chosen for the drilling rig, an access road is being laid, and power supply, water supply and communication systems are being brought up. If the terrain is uneven, then a site is planned.

Offshore well drilling

Currently, the share of black gold extracted from offshore deposits accounts for about 30% of all world production, and gas - even more. How do people get to this wealth?

The simplest solution is to drive piles in shallow water, install a platform on them, and a drilling rig and the necessary equipment are already placed on it.

Another way is to "extend" the coast by filling the shallow water with soil. So, in 1926, the Bibi-Heybat bay in the Baku region was filled up and an oil field was created in its place.

After large deposits of black gold and gas were discovered in the North Sea more than half a century ago, a bold project to drain it was born. The fact is that average depth most of the North Sea barely exceeds 70 m, and some parts of the bottom are covered with only a forty-meter layer of water. Therefore, the authors of the project considered it expedient with the help of two dams - across the English Channel in the Dover region, as well as between Denmark and Scotland (more than 700 km long) - to cut off a huge section of the North Sea and pump out water from there. Fortunately, this project remained only on paper.

In 1949, in the Caspian Sea, 40 km from the shore, the first in the USSR oil production rig in the open sea was drilled. Thus began the creation of a city on steel piles, called "Oil Rocks". However, the construction of overpasses extending for many kilometers from the coast is very expensive. In addition, their construction is possible only in shallow water.

When drilling oil and gas wells in deep seas and oceans, it is technically difficult and economically unprofitable to use stationary platforms. For this case, floating drilling rigs have been created that can change drilling areas independently or with the help of tugboats.

There are jack-up drilling platforms, semi-submersible drilling platforms and gravity-type drilling platforms.

Encyclopedia of the investor. 2013 .

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, drilling different types such workings.

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 occur 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 (absorbing, water intake, and so on).

The very extraction of raw materials 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 sink 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 into Murmansk region to study the deep structure of the Earth.