Lecture 1
First let's define the terms:
« Borehole
wellhead "well bottom"
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 - ;
During hydrocarbon exploration.
- ,
-
- Hydrogeologists – ,
- ,
- ,
-
-
History of MGRI - RGGRU
In September 1918 year, the Moscow Mining Academy was created, in which there was geological exploration faculty officially considered the founder MGRI-RGGRU.
IN 1930 year, the one-of-a-kind Moscow Geological Prospecting Institute emerged from the MGA - MGRI, Thus, MGRI-RGGRU has two years of birth - 1918 and 1930.
MGRI graduates have always occupied a worthy place in the science and practice of geological exploration, hydrogeology, engineering geology and other branches of the national economy.
From 1975 to 1989 Minister of Geology of the USSR was a graduate MGRI specialty "Reconnaissance Technology" - RT-48 (second graduation) Evgeny Alexandrovich Kozlovsky.
MGRI educational and scientific site
At the end of November 1935, MGRI was transferred from the Moscow Electromechanical College to a plot of land near the village of Ryazantsy, Zagorsky (now Sergiev Posad) district of the Moscow region. The order from MGRI read:
" §1. To improve the educational and practical work of students and conduct basic field educational practices for students: geophysical, geodetic exploration And engineering-hydrogeological, as well as to organize an experimental training and research site within the NIS to carry out research and experimental work.
Since that time, training practices for students of all major specialties: geologists, hydrogeologists, geophysicists, exploration technicians, including training drilling practices, have been constantly conducted at the test site.
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 well drilling Table 1
| Methods, types and varieties of drilling | Drilling parameters | Main Applications | |||||||
| Rock category by drillability | Well depth up to, m | Well diameter mm | |||||||
| Shock-rope | I - XII | 140 - 700 | Placer exploration. Drilling for water | ||||||
| Drilling shallow wells without circulating cleaning agent | Shallow Impact Drilling | I–III | 93 – 168 | Engineering Geology, Geological exploration (search and survey). Exploration of placer deposits. Small water supply. Explosive seismic wells. Explosive during open-pit mining in coal mines. Technical wells (in construction, mining, etc.). | |||||
| Slow rotation and combined | I–V | 30 - 50 | 112 – 250 | ||||||
| Compression drilling and screw drilling | I–III | 24 - 40 | 50 – 65 | ||||||
| Vibration, vibration-impact and vibration-impact-rotational | I – IV I - V | 93 – 168 | |||||||
| Auger | I - IV (V) | 60 -250 | |||||||
| Mechanical rotary with circulation of cleaning agent | Geological exploration | Coreless (with solid face) | I–XII | Not limited | 73 – 151 (250) | Geological exploration wells in intervals where core is not needed | |||
| Kolonkovoe | Simple projectiles | Carbide | I–VIII | » 1500 | 36 - 151 | It is advisable to drill hole depths of up to 200–300 m; deeper it is better to use SSC. | |||
| With STM cutters | V - VIII | 36 – 132 | |||||||
| Diamond | VI - XII | 36 – 112 | |||||||
| Simple projectiles with a downhole mechanism | Water hammer Impact-rotational Rotational-impact | VI –XI IX - XII | ≈ 500 » 1500 | 59 – 151 59 - 76 | With carbide crowns. With diamond bits against polishing of diamonds and self-jamming of the core. | ||||
| Pneumatic impact Impact-rotational | VI - XI | » 500 (up to 1000) | 76 - 300 | In dry and low-water wells. | |||||
| With high pressure compressor. | |||||||||
| With downhole motor | » 1500 | 59 - 76 | To deflect the well interval during directional drilling. | ||||||
| Mechanical rotary with circulation of cleaning agent | Special projectiles with core lifting without pipe lifting | Projectiles with removable core receiver KSSK, SSK, LJNGYEAR and similar | V – XI (XII) | 1500 – 3500 | 46 – 95 (47 -145) | For well depths of more than 200 - 300 m. A modern progressive option! | ||
| Projectiles (Kits) with hydro (pneumatic) transport of core or sludge KGK, KPK | I - V | 300 - 500 | 76- 250 | Progressive method, but only in weak breeds. Progressive version with annular hammer for hard rocks up to 1200 m. | ||||
| Operational | Drilling production wells for oil and gas | Rotary | I - XII | (with horizontal termination up to 13000m) | 120 - 490 | Additional exploration and production of oil, condensate and gas (Applied before 2008) | ||
| With movable rotator | ||||||||
| Turbodrill | V - XII | |||||||
| Hydraulic motor | ||||||||
| Electric drill | 146 - 390 | |||||||
| Drilling water intake and hydrothermal wells | I - IX | 200 - 350 2000-2500 | 112- 350 | Extraction of water, brines and hydroheat | ||||
| Drilling geotechnological wells | I - IX | 50 -700 | 70 - 500 | Extraction of solid minerals (uranium, sulfur, iron, etc.) | ||||
| Drilling technical, scientific and auxiliary wells | I - XII | 10 - 12300 | 70 - 900 | |||||
| Physical methods of rock destruction | Hydraulic drilling | I - IV | In combination with TPI mining. | |||||
| Thermodynamic drilling | VI–XII | For drilling blast holes. | ||||||
| Blast drilling | V - XII | Effective, but dangerous. | ||||||
| Thermostatic melting | VI - XII | Experienced. | ||||||
| Plasma drilling | VI - XII | Experienced. | ||||||
| Electric pulse drilling | IV - VII | Experienced. | ||||||
| Laser drilling | Experienced. | |||||||
| Cavitation drilling | Experienced. | |||||||
| Jet | Experienced. | |||||||
| Magnetostrictive | Experienced | |||||||
| Ultrasonic | Experienced |
Lecture 3
Rice. 6
The choice of well direction is determined by the most complete solution of geological problems. The most accurate information about the formation rocks (structure, thickness of the formation) is obtained when the well intersects the formation at the 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 transitioning from rocks of one hardness to rocks of another hardness, layering, fracturing, anisotropic properties of rocks, and others), as well as technical and technological ones. As a result, the wellbore becomes bent during the drilling process, and it is very difficult or even impossible to drill a straight well in such conditions. This curvature of the borehole axis is called natural. In these cases, it is advisable to design a curved well route in advance, taking into account the factors causing curvature. Moreover, curved routes are often not only easier to implement, but also more rational than straight ones.
Since to drill a well along a given route it is necessary to use special technical means and technological methods, in this case the curvature of the well is called “ artificial curvature", and the work of executing such a route is called " directional drilling»
Curvilinear routes, like rectilinear ones, can have any direction and are distinguished 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 practice uses multilateral drilling(incorrect multilateral well), when from one site (due to the rotation of the machine rotator) several wells are drilled sequentially at different angles with one drilling rig (Fig. 9 a, b)
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This solution provides 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 savings on laying transport routes and equipment of sites, as well as reducing environmental damage.
Well route design is carried out in the following sequence:
1. The choice between single-hole and multilateral wells. In this case, first of all, economic feasibility and the need to solve geological problems play a role. Issues of environmental protection are now beginning to play a particularly important role - with every transportation and installation of a drilling rig, serious damage to nature is caused - this must be taken into account.
2. If a single-hole well is selected, its direction is determined: vertical, inclined, horizontal, rising. In terms of labor costs, they increase in the order of the (previously) named areas.
3. The next step is to determine the straightness or curvilinearity of the well route. In the simplest geological sections (with monotonous occurrence of layers or in monolithic massifs), a straight line is usually chosen. In the case when, due to geological and technological reasons, the well will be curved, it is more profitable to use natural curvature and design a curved well route. At the same time, it must be taken into account that as the intensity of well deflection increases, the difficulties of its implementation also increase (power costs and the possibility of breakage of drill pipes increase). It is generally accepted that the permissible curvature intensity is no more than 0.05 degrees/m. A curved route is designed to solve certain problems and can be more effective than a straight one. For example, when cutting steeply dipping formations with a well, a straight inclined well must be laid with a large inclination 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 final part of which, entering the productive formation, approaches a horizontal position and runs along the formation, 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.
SSK drills differ from simple ones in that they consist of a string of special drill pipes having the same internal cross-section as that of a core pipe. A thin-walled core receiver pipe is placed in the core pipe, into which a core column enters during drilling (Fig. 13 c). After filling the core receiver with core, a special catcher is lowered from the surface on a thin cable into the drill pipe string, which captures the head of the core receiver pipe and a high-speed winch, the core receiver with the core inside drill pipes rise to the surface. Thus, instead of several hours for tripping and lifting operations when drilling deep wells, it will take several tens of minutes to recover the core from the well. Taking into account the fact that SSK shells are much more expensive than simple shells, it is more profitable to use simple shells for drilling shallow wells (up to approximately 200 - 300 meters), and for deeper ones it is more profitable to use SSK shells.
When drilling with hydraulic or pneumatic core transport, a double string of drill pipes is used. The flow of cleaning agent is supplied to the bottom through the gap between the outer and inner pipes. At the bottom, the flow turns and rises up along the internal column, bringing pieces of core 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 drilling method, no additional time is spent on core recovery, which allows for a sharp increase in productivity. However, high productivity is only possible when drilling in soft and weak rocks, where the rock is easily destroyed and mechanically removed from the bottom into the inner pipe. The second limitation of the use of KGC and KPC is the relatively small depth of the wells. Typically, well depths are up to 500 meters. Greater depths can be achieved using blowdown in combination with ring hammers and high pressure compressors (up to 2.5 MPa).
The third option for choosing types of drilling, depending on geological conditions, is associated with the use of drilling equipment (simple or special) with an additional downhole mechanism or a special core set.
In special cases the following may be used:
Mechanisms that create shock pulses on a rock cutting tool (RDT): a)) during drilling with flushing – hydraulic hammers, b) when drilling with blowing or drilling with foam – Hammers;
- downhole screw hydraulic motor;
Special core sets for obtaining conditioned core in difficult geological conditions.
Impact pulses to the bottom during rotary drilling are used to solve a number of problems:
The ability to drill vertical, strictly straight wells due to the fact that there is no need for an axial load on the drilling device; the drill bit weighs in the well like a plumb line and does not bend, as with rotary drilling with an axial load;
Increase the drilling speed due to additional impact destruction of the rock, especially during air 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 shock drilling, the friction of the cutters on the rock and the core in the core pipe is significantly reduced. This allows you to combat polishing of diamond crowns and self-jamming of the core in the core pipe.
Downhole Screw Hydraulic Motor small diameter can be used when drilling both geological and exploratory oil and gas wells.
The peculiarity of the use of downhole motors is that the drill pipe string does not rotate during the drilling process, but only the rock cutting tool rotates - a bit or a core pipe 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 effective drilling. However, the ability to drill without rotating a pipe string with a downhole motor is successfully used for directional drilling, when the well path needs to be deviated in the desired direction at the desired angle. A downhole motor included in the tool on a “crooked adapter” allows for high-quality control of the direction of the well path.
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 the washing liquid), such core sets protect the core from destruction due to erosion, rotation of the core pipe, and destruction by the crown cutters. Since obtaining a complete core is of paramount importance for geologists, this issue will be discussed in detail during practical classes.
Lecture 6
Rice. 14
6. In addition to the graphic image, the well design is determined by its code and an explanatory note justifying 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.
Example of a well design description ( in Fig. 15) with a code.
 |
Rice. 15
Ts(20) 112/108tsb(220), 93/89tsp(440...480), 76(1000)
Basic cipher designations:
132 - number indicating drilling diameter
/ - sign indicating pipe fastening
127 - the number behind the / sign indicates the diameter of the casing pipes,
(20) - the number in parentheses after the size of the casing pipes indicates the depth to which the well is cased
(440….480) - installation interval of a hidden column
Additional cipher designations:
C is a sign of cementation of the entire column. Placed behind the diameter of the casing pipes.
Cb - a sign of cementing only the shoe (lower part) of the column
TsP - a sign for cementing the shoe and the upper end of the secret casing
; - sign of well expansion. Placed before the designation of the diameter of the tool that expands the well
Designation applicable to stepped casing
" - designation of the casing string being extracted. Placed before the designation of the diameter of the casing string, after which the length of part of the string may be indicated in brackets if not all of it is removed.
The given designations cover the entire range of parameters included in the usual concept of well design or depicted on design diagrams. However, if necessary, you can enter any other additional letter indices.
In this example: - the well is drilled with a bit with a diameter of Ø 132 mm and secured with a guide pipe Ø 127 mm to a depth of 20 m. Here pipes Ø 127 mm are cemented over their entire length. Further, the drilling diameter was 112 mm to 220 m, and the well was secured to this depth with a Ø 108 mm jig. For a column with a diameter of 108 mm, only the shoe (the lower part of the column) is cemented. Further drilling is carried out with a Ø 93 mm bit to a depth of 480 m. In the interval from 440 to 480 m, the complications zone and the wellbore are secured with a secret column Ø 89 mm (the shoe and the upper part of the secret column are secured with cement). Up to a depth of 1000 m, the well has a Ø 76 mm without reinforcement.
Rice. 16
Rice. 17
Another feature of the construction of oil and gas wells is the critical importance of horizon isolation in order to exclude fluid flows from different horizons. Isolation of the annulus space of almost all casing strings is carried out by cementation. Since when drilling oil and gas wells it is necessary to isolate formations with fluids of various compositions, including aggressive ones that are dangerous if they enter productive formations and with different pressures, cementation of 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 cementing quality control. Therefore, geophysical methods for monitoring the quality of cementation are given paramount importance. In practice, to study the technical condition of a well, the method of radioactive isotopes, the acoustic method, and the method of well thermometry are used; these methods determine the height of rise of the cement slurry in the annulus, identify places of annular circulation, and the state of contact of the cement stone with the 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 the earth’s crust, ice massifs and artificial structures, which is significantly 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) both during deepening (drilling) and at the end of deepening is called "well bottom"
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 – “the distance between the wellhead 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 swelling of the rocks.
Well construction - (well construction), Performing the entire range of work, starting with site preparation and installation of the drilling rig and ending with reclamation of the territory after drilling, as a result of which the well is drilled, the results are obtained, and the well is abandoned or closed.
Well drilling - performance of a complex of works, starting from drilling to completion of deepening upon reaching the final depth and completion of all work in the well.
Well deepening - a drilling process in which the rock at the bottom of the well is destroyed and the bottom moves forward.
Drilling technology - « a series of sequential choices and decisions that ensure the effective execution of the process, including the choice of technical means and methods for performing the process" In a narrower sense, technology includes selection of process control methods and parameters drilling The concept of drilling mode closely corresponds to this narrow meaning.
Technical means for drilling wells - drilling equipment, drilling tools, instrumentation (instrumentation), automation and control equipment (CA and CS).
What is a borehole.
The well can be drilled not only downwards, but also obliquely and horizontally and even upwards.
The well axis can be straight or curved; (Fig.3)
The diameter of the wellbore can change in steps (Fig. 1)
The diameter of the wells can be 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;
When exploring solid minerals,
During hydrocarbon exploration.
- determination and calculation of mineral reserves,
- compilation of geological maps and sections.
- Hydrogeologists – carrying out engineering-geological research,
- obtaining hydrogeological information,
- design of water intake and observation wells,
- development of water wells.
- design and development of drainage wells.
Vladimir Khomutko
Reading time: 5 minutes
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What is an oil well?
It is difficult to imagine modern life without petroleum products. They are made from oil, which is extracted using special mining operations. Many of us have heard the term "oil well", but hardly everyone knows what it really is. Let's try to figure out what this structure is and what they are like.
A well is a cylindrical mine opening whose diameter is many times less than the total length of its shaft (depth).
In addition to the well, there are also mining workings such as a well and a mine. How do they differ from the definition we are considering? It's actually quite simple. A person can get into a mine or well, but not into a well. Thus, an additional definition of this structure is as follows: a mine opening, the layout 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 simply drilled would be incorrect. These capital structures, complex in their structure, are rather built underground, and therefore they are classified as the organization’s fixed assets, and the costs of their drilling and arrangement are capital investments.
Construction of oil and gas wells
The well design is selected at the design stage and must meet the following requirements:
- the design should provide free access to the bottom of geophysical instruments and downhole equipment;
- the design must prevent the collapse of the barrel walls;
- it must also ensure reliable separation of all passable layers from each other and prevent the flow of fluids from layer to layer;
- if necessary, the design of this excavation should make it possible to seal its mouth if such a need arises.
The construction and installation of oil and gas wells is carried out as follows:
- The first step is to drill an initial large-diameter shaft. 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 installed with special casing pipes and cemented. The purpose of the direction is to prevent erosion of the upper soil layer during further drilling.
- Further, to a depth of 500 to 800 meters, a shaft of smaller diameter is drilled, into which a column of pipes, called a conductor, is lowered. The space between the pipe walls and the rock is also filled with cement mortar to its entire depth.
- Only after the direction and conductor have been arranged, the well is drilled to the depth specified by the design, and a pipe string of even smaller diameter is lowered into it. This column is called operational. If the formation depth is large, then it is possible to use so-called intermediate pipe columns. 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 water, and below this depth (depending on the development region) 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 that prevents salinization of surface fresh waters and does not allow harmful substances that are concentrated in the lower layers to penetrate into them.
What types of wells are there?
Depending on the geological conditions in which oil fields are located, different types of such workings are drilled.
Main types of wells:
- vertical;
- oblique directional;
- horizontal;
- multi-barrel or multi-hole.
A well is called vertical if the angle of deviation of its trunk from the vertical is no more than five degrees.
If this angle is more than five degrees, then it is already an oblique-directional type.
A well is called horizontal if the angle of deviation of its trunk from the vertical is approximately 90 degrees. However, there are some nuances to this definition. Since “straight lines” are rarely found in living nature, and the developed strata most often lie with some slope, then from a practical point of view, as a rule, there is no point in drilling strictly horizontal wells.
It is easier and more efficient to direct the barrel along the optimal trajectory. Based on this, we can define the horizontal type of such workings as a well that has an extended shaft, drilled as close as possible to the direction of the target productive formation while maintaining the optimal azimuth.
Wells that have two or more trunks are called multilateral or multilateral. Their difference from each other is in the location of the branching point, at 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 multi-shaft. If this point is located within the productive horizon, then this is a multilateral well type.
Simply put, if the main trunk is drilled to the developed formation, and additional branches are drilled inside it, then this is a multilateral type (the productive formation is broken through at one point). All other workings with several shafts are classified as multi-barrel (several points of penetration of the formation). Also, this type of well is typical in cases where the layers are located at different horizons.
In addition, there are also 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:
Exploration 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 method for developing a field, therefore special attention is paid to exploration.
Production drilling creates the following types of workings:
- main (production and injection);
- reserve;
- control;
- evaluative;
- 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 developed formation by injecting steam, gas or water into it, as well as other working media. They are intra-contour, peri-contour and contour.
Reserve ones are necessary for the development of individual and stagnant zones, as well as pinch-out zones that are not included in the contour of the main wells.
Controls are needed to monitor the current position of the contact zones of the extracted resource and water and other changes in the formation under development. In addition, they help control pressure in productive formations.
Estimators are needed for a preliminary assessment of fields being prepared for development. They help determine the boundaries and sizes of reserves, as well as other necessary preliminary parameters.
Duplicate ones are used during the replacement of wells in the main stock that are being liquidated due to physical wear or accidents.
Through special ones, process water is extracted, industrial water is discharged, open fountains are eliminated with their help, and so on.
The process of drilling an oil well, by the nature of its impact on rocks, is:
- mechanical;
- thermal;
- physico-chemical;
- electric and so on.
Oil well design
Industrial development of deposits involves the use of only mechanical methods, which use different drilling modes. All other drilling methods are in experimental development.
Mechanical drilling methods are divided into rotary and percussion.
The impact method is the mechanical destruction of rock, which is carried out by a special tool suspended on a rope - a chisel. 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 the drilling mast. The reciprocating movement of the bit is provided by a special drilling rig. The barrel acquires a cylindrical shape due to the rotation of the bit during operation.
Cleaning the face of destroyed rock is carried out 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, and its valve is opened in the face. The bucket is filled with liquid with pieces of rock, the valve closes, and the full bailer lifts to the surface. That's it, you can continue drilling.
In Russia, shock drilling is practically not used at the moment.
The rotational method is based on immersing the bit into the rock mass by simultaneously applying vertical load and torque to the tool. The vertical load allows the bit to be driven into the rock, and then, using torque, the bit chips, wears and crushes the rock.
According to the method of location of the power unit, rotary drilling is divided into rotary and downhole drilling. In the first case, the engine stands on the surface, and the torque is transmitted to the bottom of 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 world's deepest well is the Kola Superdeep Well (SG-3). Its depth is 12,262 meters. It was drilled in the Murmansk region to study the deep structure of the Earth.
Enough broad term "well drilling" involves not only drilling for the extraction of resources from the subsoil, mainly hydrocarbons, but also work on drilling wells for water extraction, horizontal directional drilling, drilling for piles, drilling for geothermal heating.
- the process of destruction of various rocks with subsequent removal of destruction products.Drilling of the wells- this is the drilling of a directed cylindrical mine working with securing the walls (barrel) of the well to prevent rock collapse.
Wellhead is the beginning of a well on the surface of the earth.
The bottom of the well is the bottom of the well.
Wellbore – well walls.
Drilling water wells - drilling a well to an aquifer(sand, limestone) and construction of a well, taking into account the equipment of the water intake zone for the possibility of drawing water from the bowels of the earth.
The most common way. It is used when drilling wells in rocks of different hardness and to different depths.
Mainly used for drilling large diameter industrial wells.
Used when drilling in stable rocks. When using a pneumatic hammer, a high speed of well creation is achieved. Relevant when performing work in areas composed of rocky or hard rocks, as well as when working with fractured rocks.
It is used when drilling wells in difficult hydrogeological conditions to a depth of 100-150 meters. This method is characterized by low drilling speed and the difficulty of drilling in unstable rocks (quicksand, aquifer sands).
The main advantages of this method include:
It is used when drilling in soft and loose rocks to a depth of 30-40 m. Auger drilling is the main drilling method for creating shallow wells for sand (filter wells, see below), for drilling holes and holes (pit drill).
Pit drills are basically hydraulic attachments based on an excavator, manipulator crane and other construction equipment. It is used to speed up the work process, replacing manual physical labor - digging holes, planting seedlings, installing poles, piles, supports and other structures fixed in the ground.
A vertical excavation is created by a rotating “drill string”. This is the name for a structure made of series-connected pipes, in the lower part of which a chisel, turbo or electric drill - tools for destroying rocks - is fixed.
To remove cuttings and drilled soil, a clay solution is pumped into the resulting shaft. With this method, drilling is carried out with flushing.
When drilling with an auger, the drilled rock rises to the surface in a spiral (like a drill).
When drilling wells with blowing, the drilled soil is blown out with a powerful air stream.
Casing pipes are used to strengthen the walls of the mine.
This is the most general idea of rotary well drilling. With its help, the largest number of these structures are built, intended for industrial, research or private use.
In relation to drilling not for industrial purposes, but for private use, engineering structures can be divided into several types of wells.
They are used to extract water from shallow (10-60 m) sand deposits.
Typical sand well design
A filter well (sand well) is a well built on unstable water-bearing rocks, represented by heterogeneous sands, sometimes with inclusions of gravel, boulders, and sandstones. An integral part of a sand well is the filter water intake part, in other words, a filter. Most often it is made from a perforated pipe with a stainless or polymer mesh wound around it.
They are used to extract formation fluid from carbonate deposits and limestone, which, in particular, in the Moscow region are located at elevations exceeding 200 m.
The stock of “private” wells today is not limited only to the production facility. When arranging a heating system, the use of heat pumps is becoming popular. This technology allows you to use the heat of the earth to heat real estate remote from central communications. For the needs of these units, vertical or inclined workings are drilled, which are filled with a working medium and thereby create a thermal circuit.
Drilling such wells is used to lay communications without trenching. Modern technologies make it possible to control the drilling trajectory and set the required direction of movement of the drill. Horizontal directional drilling is in demand when conducting communications in densely populated areas, under overpasses, bridges, roads, oil pipelines and other capital structures.
Directional drilling is ideal for connecting to utility networks in densely built areas.
The depth of the deposits and the properties of the rocks to be penetrated determine what equipment to use for drilling wells. For the private sector, the most widely used installation is on the URB 2-A2 wheeled chassis, which is used for work in the entire “range of elevations,” even if the deposit is more than 200 m away from the surface.
Drilling rigs on wheeled chassis (KAMAZ, Ural) are also used when drilling at shallower depths, when the section consists of hard rocks.
At depths of up to 100 m, small-sized and self-propelled units are used, which can be placed on a trailer - Drill unit Strong, Partner of the TS, TM series, on a tracked base - Partner series SBU, Lutz Kurth, Drill unit SBU.
When drilling wells for industrial purposes, URB-3A3, 1BA-15V installations are mainly used.
The Vodnaya Pomoshch company has a wide fleet of drilling equipment and is capable of solving problems of autonomous water supply in difficult hydrogeological conditions, in areas with limited access, throughout the Moscow region and neighboring areas. Provides a full range of installation and maintenance services for engineering and technical support networks.
Drilling is construction of a well, as well as the destruction of layers of the earth with the subsequent extraction of destruction products to the surface.
— process destruction of rocks using special equipment - drilling equipment.
There are three types drilling:
Vertical drilling
Directional drilling
Horizontal drilling
Well drilling is process construction of a directed cylindrical mine working 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 a 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.
1. Filter well for water in sandy horizons.
To identify the presence of an aquifer in sandy soils, exploratory drilling is first carried out.
When drilling an exploration well, there can be 3 situations:
1) Availability of water for the construction of a water well, in the presence of a layer of water-saturated sand with a thickness of > 0.8 m.
2) Availability of water for the construction of a well - when interlayering water-saturated sand and other types of clay soils.
3) Lack of aquifers.
An exploration well for water is usually drilled to a depth of 13-15 meters. The cost of exploration drilling is 1000 rubles/meter. If, during exploratory drilling, aquifers are found for the construction of a water well, price meters of exploration drilling is included in price meter of drilling a water well.
If an aquifer is discovered, a production well with a filter and casing is drilled into it to construct a well. The depth of such a well is usually 13-25 m. Drilling a well at sand produced by a combined screw and shock-rope method. When drilling, metal pipes with a threaded connection type with a diameter of 168 mm are used as an external casing (to hold the walls of the well during drilling). After installing the production casing with a filter inside the outer casing pipes, the outer pipes are removed.
The production casing of a sand well consists of three parts:
1. Working column - located from ground level to the level of the aquifer. The pipes of the working string, on the one hand, “case” 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 galloon mesh (0.2 - 0.315 mm).
Through a filter column, water enters the well from the thickness of water-saturated sand, and a mesh filter prevents the entry of sand particles.
3. The storage tank is a blind pipe, closed at the bottom with a plug, which serves for uninterrupted water supply (water supply).
2. Well for an aquifer in Ordovician limestones.
A limestone well is drilled into an aquifer located in limestone cracks. Limestone - rock, predominantly consisting of calcite (calcium carbonate). Drilling wells into aquifers in limestone is done 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 water well, no external metal pipes are required to hold the walls of the well - due to the hardness of the limestone. The depth of such a well is usually 15-40 m.
The “limestone” well 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 water wells for the Cambro-Ordovician, Lomonosov aquifers and the Vendian aquifer complex (Gdov horizon).
Artesian aquifers, in our region, are confined to deep-lying sandstones, which are covered on top by layers of waterproof rock (clay thickness), forming a barrier to the waters of Quaternary sediments. The water contained in the caverns of these sandstones is located at a depth under high pressure. When such an aquifer is opened by a well, the water level under pressure rushes to the surface of the earth and is usually established at a depth of 5-15 meters.
The first artesian wells, from which water rushed 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/hour and have a depth of 80 m. They are drilled for water supply to enterprises, cottage villages or detached residential buildings.
Drilling of artesian wells is carried out if the customer has a license for the right to use the subsoil plot for the purpose of geological study.
The impact projectile is suspended on a rope, which is supplied from the instrumental drum. During chiselling, the projectile is raised and dropped using a balancer - the pulling mechanism of the machine, or from a winch. When dropped, the projectile falls down under its own weight, destroying the rock at the face. As the well deepens, the drilling line is released from the tool drum, feeding the bit. Having drilled a certain interval of the well, they stop chiseling and begin cleaning the face. This operation is performed with a bailer. After cleaning the well, they continue chiseling or begin to support the well - unstable intervals are secured with casing pipes.
Drilling is
A drilling rig for drilling drilling equipment consists of a bit, a striking rod, scissors (jasses) and a rope lock (ropsocket).
The following types of chisels 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 drill bits rocks.
When percussion drilling of placer deposits, to drive the leading casing simultaneously with deepening the well, a driving half-rod and an impact head are additionally used as part of the projectile.
Drilling is
To remove destroyed rock from the face and when drilling layers of quicksand, a bailer tool is used in the following composition: bailer, scissors and rope lock. Sometimes a short shock rod (half rod) is added.
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 there is no need 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, and the method is more energy-consuming. Also, when drilling in rocks above category III in the immediate vicinity of buildings, damage to foundations is possible from the resulting vibration when the bit hits the bottom.
It has several main directions: auger, core, drilling with direct and reverse circulation, drilling with purge.
With the auger method of drilling soft and loose rocks, rock destruction at the face is carried out with a rotating bit of various designs; the destroyed rock is transported from the face to the day surface by augers, which are a single screw conveyor. When auger drilling with an annular face, magazine augers and special bits are used. This type of drilling is the most common and most versatile method of all types of shallow drilling. It is used when drilling in rocks from categories I to VI in terms of drillability, including gravel and pebbles and in rocks containing small boulders. Auger drilling is widespread due to the fact that when drilling in most rocks, the walls of the well are simultaneously secured with the rock being lifted.
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, and it is impossible to drill in rocks above category VI.
Drilling is
In core drilling, rock destruction at the bottom is carried out by cutting an annular channel by rotating a core pipe with a drill bit placed at its end. In this case, in the central part of the face (inside the core pipe) a core is formed in the form of a column (monolith) of an undisturbed structure. After a core of sufficient length has been formed, it is torn from the massif using a core grabber installed on a core pipe immediately above the crown and raised to the surface. Often core drilling of rocks is carried out with bottom-hole circulation of the flushing fluid, less often with flushing of the wellbore with a clay solution. Instead of washing, blowing the bottom with compressed air is also used. Blowing 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 bottom;
The possibility of contamination and moistening of the sludge, as well as the mixing of differences in sludge carried from different horizons is eliminated.
And of course, such an important point as the delivery of water to wells is excluded.
Core pipe
The main disadvantage preventing the widespread use of this method is the geological and hydrogeological limitation of drilling possibilities: bottom hole blowing is most appropriate and effective to carry out in wells that do not contain liquid water.
The main advantage is the high penetration rate in rocks from category V and above. Possibility of extracting core with an undisturbed structure to the surface.
Of the total volume of water well drilling, more than 85% is performed using a rotary method with flushing with industrial water or clay solution. Water, clay solutions treated with nonionic surfactants (OP-7, OP-10, etc.), water-hypane (3-5%) and carbonate solutions are used as a flushing liquid when opening aquifers. When drilling using the rotary method, two types of flushing are used: direct and reverse.
Drilling is
In direct flushing, the flushing fluid is supplied to the rock-cutting tool through the drill pipes and rises to the surface through the annular gap between the drill pipes and the walls of the well, carrying with it pieces of destroyed rock (sludge).
During backflushing, 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; b - reverse; 1 - well walls; 2 - guide pipe; 3 - drill pipe; 4 - oil seal; 5 - drainage of flushing liquid; 6 - cover; 7 - supply of flushing liquid; 8 - adapter.
Continuous face drilling is carried out using roller bits, the type of which is selected based on the category of the rock being drilled.
Circular face drilling with direct flushing is carried out using core sets with carbide or diamond bits.
Main advantages: The drilling speed of this method in soft and medium-hard rocks 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 with cable-percussion drilling. Significantly lower energy intensity and energy consumption compared to other methods.
The main disadvantage is the provision of water and clay to drilling rigs.
In direct circulation drilling, the processes are generally the same as in direct circulation drilling. Only instead of a solution, compressed air is supplied through the swivel seal. And the destroyed rock (sludge) is blown to the surface. Drilling is carried out with air hammers, as well as roller bits or core bits with diamond or carbide bits.
Drilling is
Since a well performs different functions than wells, when working there is no point in looking for high water and determining the optimal location. Customers, or if you are drilling for yourself, I can choose the site for the well yourself, in the place where it is convenient and will have the best effect.
This is all the more effective because 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.
The question is by no means an idle one, since there are significant differences in the technology of breaking through clay or rocky soils. Don't forget. that at different depths the soil type may change, this is worth taking into account and changing equipment and nozzles.
The most labor-intensive, slow and expensive drilling process is the development of calcareous, hard and rocky layers and soil types.
A typical mistake of beginners is that in an effort to quickly pass through an unpleasant section, the speed increases, which is why the drill “bites” and Job stops completely. On the contrary, the revolutions of the drilling equipment should be 30-40, then you will stably pass through a difficult section.
You will be able to break through strong and hard ground much easier. If you use a roller bit, a roller cutter with a rectangular tape 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 use, so such sandy layers are also passed through. The biggest difficulty is that the sand crumbles and can fill up and ruin the whole work. To avoid this, special additives are added to the circulating 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 should always flow out of the wellbore. If not, then you need to raise the rod column and use a motor pump. When building up bars, raise the columns. Pass air columns along the rods to clean the tools.
Based on the method of impact on rocks, a distinction is made between mechanical and non-mechanical drilling. During mechanical drilling, the drilling tool directly affects the rock, destroying it, and during non-mechanical drilling, 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 impact and rotary.
During impact drilling, rock destruction is carried out by bit 1 suspended on a rope (Fig. 3). The drilling tool also includes a striking 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). The reciprocating movement of the drilling tool is provided by the drilling rig 6.
1 - bit; 2 - shock rod; 3 - rope lock; 4 - rope; 5 - block; 6 - drilling rig.
As the well deepens, the rope is lengthened. The cylindricity of the well is ensured by turning the bit during work.
To clear the face of destroyed rock, the drilling tool is periodically removed from the well, and a bailer, similar to a long bucket with a valve in the bottom, is lowered into it. 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 lifted, the valve closes and the mixture is removed to the top.
After cleaning the bottom is completed, the drilling tool is lowered into the well again and drilling continues.
To avoid collapse of the well walls, a casing pipe is lowered into it, the length of which increases as the bottom deepens.
Currently, shock drilling is not used in our country when drilling oil and gas wells.
Oil and gas wells are constructed using the rotary drilling method. With this method, rocks are not crushed by impacts, but are destroyed by a rotating bit, which is subject to an axial load. Torque is transmitted to the bit or from the surface from the rotator (rotor) through the drill pipe string (rotary drilling) or from a downhole motor (turbo drill, electric drill, screw motor) installed directly above the bit.
Drilling is
A turbodrill is a hydraulic turbine driven into rotation by means of flushing fluid injected into the well. An electric drill is an electric motor protected from liquid penetration, power to which is supplied via a cable from the surface. A screw motor is a type 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.
Based on the nature of rock destruction at the bottom, a distinction is made between continuous and core drilling. During continuous drilling, rock destruction occurs over the entire face area. Core drilling involves 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. Using core selection, 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:
cutting and shearing bits that destroy rock with blades (blade bits);
crushing and shearing bits that destroy rock with teeth located on roller cones (cone bits);
bits with cutting and abrasive action, destroying rock with diamond grains or carbide pins, which are located in the end part of the bit (diamond and carbide bits).
Drilling rig: 1 - bit; 2 - above-bit weighted drill pipe; 3 - sub; 4 - centralizer; 5 - coupling sub; 6, 7 - weighted drill pipes; 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 - mud pump
Wells for oil and gas can be systematized as follows:
structural-search, the purpose of which is to establish (clarify tectonics, stratigraphy, lithology, assess the productivity of horizons) without additional well construction;
exploration, serving to identify productive objects, as well as to delineate already developed oil and gas-bearing formations;
extractive (exploitation) intended for the extraction of oil and gas from the earth subsoil. This category also includes injection, appraisal, observation and parametric wells;
injection, designed for pumping water, gas or steam into formations in order to maintain reservoir pressure or treat the bottom-hole zone. These measures are aimed at extending the period of the fountain method oil production or improving production efficiency;
advancing the extractive ones, serving for oil production and gas with simultaneous clarification of the structure of the productive formation;
assessment, the purpose of which is to determine the initial oil-water saturation and residual oil saturation of the formation (and conduct other studies);
control and observational, designed to monitor the development object, study the nature of the movement of formation fluids and changes in the gas and oil saturation of the formation;
reference wells are drilled to study the geological structure of large regions in order to establish general patterns of occurrence of rocks and identify the possibility of the formation of deposits in these rocks black gold and gas.
Drilling is
The well construction cycle includes:
preparatory work;
installation of tower and equipment;
preparation for drilling;
Drilling process;
fastening the well with casing pipes and its plugging;
formation drilling and inflow testing black gold and gas.
During the preparatory work, a site for the drilling rig is selected, an access road is laid, and power supply, water supply and communications systems are installed. If the terrain is uneven, then plan a site.
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 into shallow water, install a platform on them, and place a drilling rig and the necessary equipment on it.
Another way is to “extend” the shore by filling the shallow water with soil. Thus, 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 the average depth of 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 advisable, with the help of two dams - across the English Channel in the Dover area, and also 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, the first offshore oil production rig in the USSR was drilled in the Caspian Sea, 40 km from the coast. Thus began the creation of a city on steel piles, called “Oil Rocks”. However, the construction of overpasses extending many kilometers from the coast is very expensive. In addition, their construction is possible only in shallow waters.
When drilling oil and gas wells in deep seas and oceans, using stationary platforms is technically difficult and economically unprofitable. For this case, floating drilling rigs have been created that can independently or with the help of tugs change drilling areas.
There are jack-up drilling platforms, semi-submersible drilling platforms and gravity-type drilling platforms.
Investor Encyclopedia. 2013 .
Borehole
(a. well, drilling hole; n. Bohrloch; f. trou de forage; And. agujero, pozo de sondeo) - bugle. production of premium round section (diameter 59-1000 mm), formed as a result of drilling. B. s. divided into small ones - deep. up to 2000 m (of which the vast majority are up to several hundred m), medium - up to 4500 m, deep - up to 6000 m, ultra-deep - St. 6000 m. In B. s. the mouth, trunk and bottom are distinguished (). According to the position of the trunk axis and the configuration of the B. s. divided into vertical, horizontal, inclined; unbranched, branched; single and bush. According to their purpose, they distinguish between research, intended for studying the earth, operational (development, see Fig.) - for the development of deposits, construction - for the construction of various types. structures (bridges, piers, pile foundations and foundations, underground storage facilities for liquids and gases, water pipelines), mining engineering. B. s. - for the construction and operation of the forge. 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 column; 2 - conductor column; 3 - drilling fluid; 4 - cement stone; 5 - production string; 6 - productive formation; 7 - perforated holes; 8 - column head; 9 - valves; 10 - cross.
Research B. s. are divided into mapping, structural-exploration, support-geological, support-technological, engineering-geological, parametric, prospecting and exploration. Operation 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 - production, injection, evaluation, control (piezometric, observation), according to operation. state - operating, repaired, inactive, mothballed and liquidated. Mining Engineering B. s. They 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 borehole and the drilling conditions, the walls of the wells are secured or left unsecured.
The barrel is not secured for mining purposes. (for example, blasting) and other shallow wells (up to 50 m), drilled in stable rock masses. Bases intended for operation and research are secured during construction. They have the most complex design, the edges are determined by the dimensions of the parts of the trunk, casing columns and the cement ring in the space behind the casing columns; type and number of casing columns; equipment of casing columns, wellhead and bottom of the B. s. Casing columns (guide, conductor, intermediate and production) are intended for fastening the wall of parts of the borehole. and isolation of decomposition zones. complications, as well as productive strata from the rest of the geol. cut. 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 (guide) part of the shaft in order to isolate the upper alluvial soil and divert the upward flow of drilling agent from the wellbore into the treatment system, and is cemented along the entire length. Conductor string () - the second casing string lowered into the borehole of the reservoir, designed to cover the upper unstable deposits, aquifers and absorption strata, permafrost zones, etc. They install on it; the annulus behind the column is usually cemented along its entire length. The intermediate casing is lowered, if necessary, after the casing to secure unstable rocks, isolate zones of complications and aquifers. The depth of descent of intermediate and conductor columns is calculated taking into account the prevention of hydraulic fracturing, the stability of the borehole wall, and the separation of application zones. drilling agents. The number of intermediate columns depends on the depth of the B. s. and complexity of geol. cut. The last casing is designed for production and isolates the productive formations. To extract fluids from productive formations into production. the column is lowered by pumping columns into the decomposition. combinations depending on the number of layers being developed and the extraction method used. In intermediate and operational part of the trunk of B. s. Instead of a full-length casing string, casing liner strings can be lowered on drill pipes, the top of which is secured using special equipment. pendants After completion of the well construction, the liner column is sometimes extended to the mouth of the well. column-extension.
To facilitate lowering and cementing of casing strings and improve the quality of these works, casing strings are equipped with guide shoes, decomp. valves, connect. and disconnects. devices, cement turbulators, packers, centralizers and scrapers. During multi-stage cementing, cementing sleeves are introduced into the casing string.
According to the number of casing strings lowered into the borehole. after the conductor, there are one-, two-, three- and multi-column well designs; by type of bottomhole zone equipment - B. s. with cased and uncased bottomhole zone. Design of B. s. with a cased bottomhole zone can be obtained either by lowering a continuous production into it. column, followed by cementing it and perforating the column, cement stone and productive formation, or lowering production into it. columns with a tail section having round or slot-like holes placed against the productive formation.
The design of gas wells is characterized by greater tightness of the casing columns, which is achieved by using casing pipes with special. connections and lubricants for them, lifting the cement mortar behind all columns to the mouth of the B. s. etc. The mouths of development oil and gas wells are equipped with special equipment. fittings. The design of a mine, intended for searching and exploring deposits of solid mineral deposits, is much simpler. The guiding part of such B. s. has a length of several. m and is secured with a guide pipe, the conductor part has a length of. 30-150 m. Next, the trunk is drilled with full core selection, and fastening of unstable rocks is carried out with quick-setting mixtures. Literature
: cm. lit. at Art. Drilling. Y. A. Gelfgat, D. E. Stolyarov.
Mountain encyclopedia. - M.: Soviet Encyclopedia. Edited by E. A. Kozlovsky. 1984-1991 .
A borehole is a cylindrical mine working, driven by a drilling tool into the rock of the earth's crust, characterized by a large ratio of its length to diameter. The beginning of a well is called its mouth, the bottom is called its bottom,... ... Wikipedia
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