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

Thus, a well is a mining opening that is created without the need for human access and has a cylindrical shape - its length is many times greater than its diameter. The beginning of the well is called the mouth, the surface of the cylindrical column is called the trunk or wall, and the bottom of the object is called the bottom.

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

Features of drilling oil and gas wells

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

• The process of deepening when rocks are destroyed by a drilling tool,


• Removing crushed rock from a well,


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


• Carrying out geological and geophysical work to search for productive horizons,


• Cementing of the production string.

Classification of oil and gas wells

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

Today, oil and gas wells are drilled to ultra-deep horizons, deeper than 6,000 meters - in this regard, the Kola well, whose depth is 12,650 meters, is very indicative.

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

There are also shock methods. They also use non-mechanical methods, among which are electric pulse, explosive, electrical, hydraulic and others. All of them are not used very widely.

Works during drilling for oil or gas

IN classic version When drilling for oil or gas, drill bits are used to break up rock, and streams of drilling fluid constantly clean the bottom. In rare cases, a gaseous working reagent is used for purging.

Drilling in any case is carried out vertically, inclined drilling is used only when necessary, cluster, directional, double-barreled or multi-hole drilling is also used.

Wells are deepened with or without core sampling; the first option is used when working along the periphery, and the second - over the entire area. If a core is taken, it is examined for the passage of rock layers, periodically lifting it to the surface.

Drilling for oil and gas is carried out today both on land and offshore, and such work is carried out using special drilling rigs that provide rotary drilling using specialized drill pipes that are connected by coupling-locking threaded connections.

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

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

New technologies for drilling oil and gas wells at the exhibition

Sharing information and learning new things can ensure optimal progress, and therefore this need simply cannot be left aside.

If you decide to join modern achievements and plunge into a professional environment, professional events are held precisely for this purpose, one of which you should definitely take part in. We are talking about exhibitions that are held annually at the Expocentre Fairgrounds and bring together hundreds and thousands of specialists in this field on the opening days.

At the annual exhibition "Neftegaz" you can easily access new developments, study advanced technologies (for example, oil and gas drilling technologies), see modern equipment and at the same time acquire useful connections to the extent necessary, find clients and partners.

Opportunities like these should not be missed, because they don’t come around very often and, with the right approach, can provide significant progress!

Read our other articles.

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

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

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

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

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

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

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

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

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

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

Let's climb up!

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

Video of how the top drive system works:

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

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

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

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

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

Pipes are fed through a special chute:

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

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

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

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

Schematically it all looks like this:

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

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

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

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

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

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

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

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

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

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

All this pumping equipment is managed by one person. Due to the noise of the equipment, he wears earplugs or hearing protection for the entire shift.

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

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

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

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

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

Drilling oil or gas wells is a complex and, in some cases, dangerous process. Drilling oil or gas wells can only be successfully carried out if certain rules and regulations are strictly followed. Well drilling is used for various purposes, including: studying the structure of the earth's crust, searching for and exploring oil, gas, water and solid minerals, as well as in the construction of roads to study soil, etc. In this case, when searching for oil and gas, deep drilling is carried out, which represents difficult process and, as a rule, labor-intensive for the people doing the drilling. It requires large material and technical means, including special tools, materials, equipment and installations.

In a number of places in our country, drilling for oil and gas is carried out in difficult geological and climatic conditions with the achievement of productive horizons at a depth of below 3 km, and often 4-5 km.

As stated earlier, drilling at great depths, including under salt-bearing strata, as well as in hard-to-reach areas of tundra with permafrost and taiga, of course, requires drillers to modern conditions carry out all types of work related to drilling deep wells for oil and gas, with special responsibility and highly qualified. Otherwise, during drilling wells, various complications are possible that can have a detrimental effect on people and environment. Therefore, a careful and responsible approach to their duties for each member of the drilling crew is the main principle of trouble-free work for drillers in the process of drilling deep wells for oil and gas.

A number of drilling crews in last years when the development of uninhabited and hard-to-reach areas began, including Western Siberia, they use shift method, t.s. drilling teams go to the well drilling site for a short time, living in camp conditions. And then they return to their stationary drilling organizations.

Drilling deep wells is carried out by mechanical destruction of rocks using special engines. There are two types of mechanical drilling: impact and rotary. Impact drilling, also called percussion-rope drilling, is as follows. We hang a bit on a rope, which periodically lowers onto the faces and destroys the rock. The rope is located on the drum of the drilling rig and can be lowered and raised using various devices.

The destroyed rock at the face, called cuttings, is periodically removed. To do this, lift the drilling tool and lower the bailer (a bucket with a valve in the bottom). When the bailer is immersed, the valve opens and it is filled with a mixture of formation or added liquid and drilled rock. As the bailer rises, the valve closes. As a result of repeated lowering and raising of the bailer, the bottom of the well is cleared, and drilling of the well continues again.

In the percussion drilling method, as a rule, no drilling fluid is used. But in order to preserve the drilled shaft, I casing the well, that is, lowering a casing consisting of metal pipes connected through threads or welding. As the well deepens, the casing is advanced to the bottom and extended by extending another pipe. If it is impossible to move the casing down, a second casing of smaller diameter is lowered inside. To do this, the well is deepened with a chisel, and the column is extended. It is possible to lower subsequent columns of smaller diameter until the design depth is reached.

The effectiveness of the impact drilling method depends on the choice of bit for drilling a particular rock, the weight of the drilling tool, the number of impacts of the bit on the bottom and other reasons.

The impact drilling method uses machines with a low weight (up to 20 tons), which makes them easy to transport for drilling shallow wells far from populated areas.

But when drilling oil and gas wells, the percussion method is not used. Drilling for oil and gas is carried out using the rotary drilling method.

Rotary drilling is performed as a result of the simultaneous impact of load and torque on the bit. This drilling method is carried out using a rotor or downhole motors: a turbodrill or an electric drill.

During rotary drilling, the power from the engine is transferred to the rotor - a rotating mechanism installed above the wellhead in the center of the tower. The rotor rotates the drill string of pipes with the bit.

When drilling with a downhole motor, the bit is screwed to the shaft and the drill string is screwed to the motor housing. When the engine is running, its shaft and bit rotate, but the drill string does not rotate. Consequently, during rotary drilling, the bit deepens into the rock while the drill string moves along the axis of the well, and when drilling with a downhole motor, the drill string does not rotate.

With the rotary drilling method, the well is flushed with water or clay solution during the entire time the bit is operating at the bottom. The flushing fluid is injected into the well and carries the drilled rock to the surface, into special containers (troughs), then it is cleaned by cleaning mechanisms and again enters the receiving tanks of the drilling pumps and is pumped into the well.

Drill pipes are lifted to change the worn bit, they are unscrewed into sections called candles. Candles are also placed on the lantern of the tower on a candlestick. Then the drill string is lowered into the well in the reverse order.

Downhole motors include: turbo drill and electric drill. The rotation of the turbodrill shaft occurs due to the conversion of the hydraulic energy of the flow of flushing fluid along the drill string entering the turbodrill into mechanical energy turbodrill, to which the bit is rigidly connected.

When drilling with an electric drill, energy is supplied to its motor through a cable, sections of which are reinforced concentrically inside the drill string.

Various rotary drilling methods have specific features of the drilling mode. The drilling mode is characterized by a complex of drilling customers, including: penetration speed, bottomhole load, bit rotation frequency, flushing fluid consumption, etc.

The optimal drilling mode is understood as a combination of drilling parameters at which the greatest effect is achieved, i.e., at a relatively low cost of material and money, high speeds drilling, and the actual wellbore is close to the design one.

For each rock, you can select the optimal drilling parameters: load on bit, bit rotation speed and flushing fluid flow rate.

In the case of drilling with a rotor, there is no relationship between the parameters of the drilling mode, so I select the optimal mode! for each parameter and separately. At the same time, depending on the geology of the section, taking into account the hardness of the rocks, the load on the bit and its rotation frequency are selected, and the flow rate of the flushing fluid is set depending on the degree of cleaning of the bottom of the well.

Unlike rotary drilling, when drilling with a turbodrill, there is a connection between the parameters of the drilling mode. For example, with an increase in the flow rate of the flushing fluid at the same load on the bottom, the rotational speed of the turbodrill also increases. And depending on the hardness of the rocks, the load changes, and the bit rotation speed changes accordingly, which leads to optimal well drilling performance. When drilling with an electric drill, unlike turbine drilling, no connection is established between the parameters of the drilling mode, however, the bit rotation speed is high, which ensures the optimal drilling mode.

In most cases, vertical wells are drilled under the project, the trunk of which is close to vertical. Vertical wells include those in which the angle between the well axis and the vertical (zenith angle) along the entire shaft has a deviation of no more than 2°. If the deviation is more than 2°, the wells are considered curved.

The reasons for the curvature of wells can be different and depend both on the natural geological conditions of well drilling and on the results of the activities of drillers and other services associated with drilling oil and gas wells. Geological reasons for the curvature of wells include: inclined layers, tectonic disturbances, the presence of caperns, interlayering of rocks of different hardness, as well as solid inclusions such as boulders, etc. Technical reasons include: curvature of drill pipes, distortion in threaded connections, etc. Technological reasons include: incorrect choice of well design, incorrect ratio of the diameters of drill pipes and wells, the use of unfavorable drilling conditions, etc.

A significant deviation from the designed wellbore leads to major drilling complications, including accidents.

As a result of involuntary curvature of the well, the following difficulties may occur: complications of tripping operations, more intensive wear of drill pipes and couplings, rock falls, abrasion of casing pipes, difficulty in lowering them into the well, increased risk of pipe collapse, complications during cementing, etc.

Bent wells are unreliable during subsequent operation and quickly fail due to premature wear of downhole pumping equipment, sucker rods and production casing.

However, in a number of cases, specially inclined and horizontal drilling of wells is carried out, including under the seabed, under ravines, mountains, in areas occupied by nature reserves, under industrial facilities and residential settlements, when extinguishing burning fountains and eliminating open oil and gas emissions, etc. .

In this case, special whipstocks are used, which are installed between the turbodrill and the drill string.

To drill oil and gas wells, bits are used, which are drilling tools for mechanical destruction of rocks. Usually, for drilling out rocks of medium hardness, hard, hard and very hard rocks, crushing and shearing bits, the so-called roller bits, are used.

In some cases, cutting and abrasive bits with diamond and carbide inserts are also used. They are used when excavating sections where there is an alternation of rocks of different hardness, including a combination of highly plastic and medium-hard rocks.

The moment of lowering the bit into the well, at which drillers use special stabilizers to ensure that the bit is accurately lowered to the center of the bottom.

The bits can be used for continuous drilling, when the rock is destroyed along the entire face, or for circumferential drilling, when the rock is destroyed along the ring of the face. In the latter case, the bits are called core bits and are used to take core from the well. In this case, drilling heads are used: roller-cone, diamond and carbide. The core bit consists of a drill head, a primer, a core set body and a ball valve. Using a soil carrier, which has core grabbers and core holders, and a wide valve at the top, the core is selected and stored until it is raised to the surface.

The drill string is designed to carry out the process of drilling a well. It connects the bit or downhole motor to the surface equipment. The drill string consists of a series of drill pipes. In the upper part there is a leading square pipe connected to a swivel. Drill pipes are screwed together using drill joints and couplings. The task of the drill string is to transmit rotation to the bit, create a load on the bit, to raise and lower the bits, carry out various auxiliary works during the process of drilling a well and testing formations.

To rotate the bit at the bottom of the well, the mechanisms mentioned above are used: rotors, turbodrills and electric drills.

The rotors provide rotational movement of the drill string and bit, and also support the weight of the heavy drill string. The rotor installed at the wellhead consists of a frame, in the inner part of which a rotating table is installed. In the center of the table there is a hole (passage) for lowering bits and drill pipes through it. The diameter of the rotor table hole varies from 400 to 700 mm, which is determined by the maximum diameter of the bit that passes through it. Inserts and clamps are inserted into the central hole, which provide suspension for the square-section drive pipe. The subsequent drill pipe is attached to the leading pipe, and then others.

Turbodrills, being downhole motors, convert hydraulic energy into mechanical energy, which ensures rotation of the turbodrill shaft and bit. The turbodrill consists of two main elements of the turbine: a stator, rigidly attached to the housing, and a rotor, fixed to the turbodrill shaft. Due to the many stages (up to 350), the hydraulic flow, flowing from stage to stage, creates powerful mechanical energy that drives the bit. The more stages in a turbodrill, the greater the power and torque, and the more work more efficiently turbo drill.

Electric drills transform electrical energy, supplied from the surface, into the mechanical energy that rotates the bit at the bottom. Electric drills, consisting of two main parts - an electric motor and an oil-filled spindle, with a screwed bit, are lowered into the well on the drill string. Energy from power transformer supplied via an outer cable and an inner cable, the latter of which is embedded in the drill string. In this case, the washing liquid, having passed through a system of subs and dubricators, enters the hollow shaft of the electric motor and then to the bit. And then, as in rotary and turbine drilling, the drilling fluid entrains fragments of drilled rock and lifts them through the annulus to the surface.

Drilling rigs vary in their characteristics depending on the depth of the wells being drilled. The rig hook load must match the weight of the drill string, and the weight of the drill string must be greater than the weight of the casing.

In this regard, drilling rigs differ in parameters (maximum permissible load on the hook), which depend on the diameter of the well and drill pipes, as well as on the mass of the latter.

Drilling rigs differ in the characteristics of drilling and power equipment.

General view of a drilling rig for drilling oil and gas wells.

The drilling rig includes a number of mechanisms that are mounted on a common base, which allows the rig to be transported from one well to another in assembled form. A typical installation for rotary drilling includes: a tower, a crane block, a traveling block, a hook, a swivel, a winch, diesel engines, a gearbox, a drilling pump, pump receiving tanks, pneumatic control, and a rotor. The installation has a metal frame, which is covered with shields and boards or rubberized fabric to protect mechanisms and people from precipitation and wind.

In addition, the installation kit includes a circulation system, which consists of a vibrating whitefish, gutters, receiving containers for flushing liquid, and discharge pipelines.

More complex drilling equipment and rigs are used for offshore drilling. As stated earlier, offshore drilling is carried out either from fixed platforms or from floating platforms and special vessels.

At the same time, stationary platforms require the construction of a metal base, rigidly fastened to the seabed. For this purpose, support blocks are used, installed by special security units, which are reliably cemented.

The drilling bases are connected by racks, and all drilling rooms are located in the areas near the rack very compactly and are covered to protect the equipment and workers of the drilling crew. Construction works at sea, the construction of the foundation and installation of drilling equipment is very labor-intensive and is carried out by special organizations.

The most modern drilling rigs have a control panel for the well drilling process, where control is carried out using buttons mounted on a compact membrane-type keyboard. For example, the driller's console for the Power Drill 2000 drive, supplied by the US company General Electric Drive System, is made in the style of modern industrial design and has closed keys that were specially designed so that they can be used accurately by a driller in thick working conditions. mittens.

Fluorescent digital displays—three programmable and one diagnostic—provide the driller with information about the rig's status and operating parameters. Automatic diagnostics and direct communication with the Power Drill 2000 drive make the console a unique tool for the driller. Every time the driller tries to set an unauthorized function, the console informs him of the error. The error that is most likely to cause the rig to stop working is identified first.

This will give the driller immediate feedback, allowing him to correct the error and resume normal operations more quickly. The operator can switch diagnostic displays to obtain more information about detected faults. The system status is constantly displayed in simple in full words on an easy-to-read software device of a specialized keyboard installed directly on the drive. Diagnostic signals are provided to the keypad using easy-to-read text, allowing rig personnel with minimal electrical knowledge to identify any level of fault within minutes.

In addition to a drilling rig with a rotor, a turbodrill or an electric drill, and a set of bits, the following equipment and materials are available at the drilling site:

• 1) drill rods and tubing;
• 2) casing pipes;
• 3) pumps for injection of liquids and compressors for injection of gas or air;
• 4) clay and various chemicals;
• 5) containers for clay solution and other flushing liquids;
• 6) cementing units and cement;
• 7) perforators and formation testers and other equipment.

Before drilling a well, the geological service, together with drilling and design organizations, draws up a geological and technical work order (GTN), which contains the geological and technical parts. Drillers begin drilling a well after the gas pump approval and signing by the heads of the organizations performing the work. The geological part of the GTN provides a predicted section of sediments at the well drilling site. The depths of exposure of various stratigraphic divisions of the section, the design section of sediments (lithological column) indicating the strength of the rocks are indicated,

the necessary intervals for core sampling and testing of formations in an open hole are given, and possible complications when drilling against certain intervals of the section are indicated, and a set of necessary production and geophysical work is given.

In the technical part, the most optimal well design is proposed, the following are indicated: conditions for testing columns, reserves of solution and chemicals, drilling methods, type of downhole motor, type, size, number of bits, well drilling mode (axial load, rotor speed, pump feed, deprivation, number of pumps), type of drilling fluid for drilling intervals of the section, parameters of the flushing fluid, chemical treatment of the solution, tool lifting speed, drill string layout, drilling rig parameters, etc.

The well design is a system of pipes of various diameters and depths of descent into the well, which ensures its rigid attachment to the walls of the shaft and adjacent rocks. Usually, in order to cover the upper part of the cut, composed of loose rocks, a pit 4-8 m deep is constructed and a large-diameter pipe with a window at the top is lowered into it. The space between the pipe and the wall of the pit is filled with rubble stone and cement mortar, which makes it possible to reliably strengthen the wellhead. Then a metal trench is welded to the window in the pipe, through which, during the drilling of a well, the flushing fluid is directed into the trench system. The pipe installed in the pit is called the direction.

After setting the direction, they begin to drill the well. After drilling loose rocks in the upper part of the section (50-400 m), a casing string of steel pipes is lowered and the annulus is cemented. The first casing is called the casing.

Then drilling continues. If complications arise during drilling later due to unstable formations, a second casing, called an intermediate casing, is lowered. In a number of cases, it is necessary to lower both the third and fourth columns in order to strengthen the wellbore.

After reaching the design depth, the production casing is lowered into the well and cemented. It can be designed either to lift oil or gas to the surface, or to inject water (gas or air) into the reservoir to maintain pressure.

The layout of casing strings, indicating their diameters, the depth of transition from a larger diameter to a smaller one, the depth of running the casing strings and their cementing intervals allows you to imagine the well design.

Depending on the number of casing strings lowered, wells can be single-column, double-column or three-column. Typically, the initial diameter of the well ranges from 400 to 600 mm, and the final diameter is 127 mm (5").

During drilling, collapses of the upper part of the sedimentary complex, composed of clays, sandstones and pebbles, were often observed; the formation of caverns in the halogen rocks of Kungur, in which breakages of the drilling tool occurred; abnormally high pressure occurred, requiring drilling with a weighted solution (1.7 g/cm3); absorption of clay solution (up to loss of circulation) when drilling porous and fractured rocks, which, in combination with abnormally high pressure, threatens open gas emissions; formation of oil seals against porous and fractured rocks of the productive strata, which leads to sticking and tightening of the drilling tool.

After the casing strings are lowered into the well, they are cemented (cemented). To do this, cement is poured into the annulus using special cement cements. Cement mortars are prepared in special cement mixing machines that arrive at the drilling site. Through cementing units equipped with pumps, cement is forced from the casing into the annulus of the well up to a certain height of cement lifting, specified in the GTN.

Drilling of productive horizons in exploration wells is carried out with core bits in order to select and subsequently study the core. After completion of drilling of productive formations, a full scope of field geophysical surveys of wells (GIS) is carried out.

Then the formations are tested using formation testers, which are based on causing an influx of oil from the formation due to a sharp pressure drop in the formation-drill string system.

Typically, a well is drilled slightly below the base of the productive horizon, the production casing is lowered and cemented once or twice. Then, after the cement has hardened, the column wall, including the cement ring, is perforated opposite the productive formation to establish a connection between the column and the formation. To do this, use various perforators (cumulative, torpedo or bullet). The most commonly used are cumulative hammer drills, based on the action of a cumulative jet that occurs due to the explosion of the copper lining of the charge and a shock wave. In this case, a thin metal stream is ejected at a speed of 8000-10,000 m/s and punches holes in the column and cement stone. A perforator is lowered into the well and a calculated network of holes is made against the productive formation.

Underground repairs of wells are carried out both during the drilling process and during their subsequent operation by special underground repair teams that carry out major and current repairs of wells. Maintenance crews usually work in shifts, just like drilling crews.

Zavgorodniy Ivan Alexandrovich

2nd year student, mechanical department, specialty “Drilling of oil and gas wells”, Astrakhan State Polytechnic College, Astrakhan

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Kuznetsova Marina Ivanovna

teacher special disciplines Astrakhan State Polytechnic College, Astrakhan

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Introduction. Since ancient times, humanity has been extracting oil; at first, primitive methods were used: using wells, collecting oil from the surface of reservoirs, processing limestone or sandstone soaked in oil. In 1859, mechanical drilling of oil wells appeared in the US state of Pennsylvania, and around the same time well drilling began in Russia. In 1864 and 1866, the first wells were drilled in the Kuban with a flow rate of 190 tons/day.

Initially, oil wells were drilled using a manual rod-rotary method, but soon they switched to drilling using a manual rod-percussion method. The shock-rod method has become widespread in the oil fields of Azerbaijan. The transition from the manual method to mechanical drilling of wells led to the need to mechanize drilling operations, a major contribution to the development of which was made by Russian mining engineers G.D. Romanovsky and S.G. Wojslaw. In 1901, for the first time in the United States, rotary drilling was used with flushing the bottom with a circulating flow of liquid (using drilling fluid), and the lifting of drilled rock with a circulating flow of water was invented by the French engineer Fauvelle back in 1848. From this moment on, the period of development and improvement of the rotary drilling method began. In 1902, the first well with a depth of 345 m was drilled in Russia using the rotary method in the Grozny region.

Today, the United States occupies a leading position in the oil industry, 2 million wells are drilled annually, a quarter of them turn out to be productive, Russia so far occupies only second place. In Russia and abroad the following are used: manual drilling (water extraction); mechanical; controlled spindle drilling (safe drilling system developed in England); explosive drilling technologies; thermal; physico-chemical, electric spark and other methods. In addition, many new technologies for drilling wells are being developed; for example, in the USA, the Colorado Mining Institute has developed a laser drilling technology based on burning rock.

Drilling technology. The mechanical drilling method is the most common; it is carried out using percussion, rotary and percussion-rotary drilling methods. With the impact drilling method, rock destruction occurs due to impacts of the rock-cutting tool on the bottom of the well. The destruction of rocks due to the rotation of a rock-cutting tool (chisel, crown) pressed to the bottom is called the rotational drilling method.

When drilling oil and gas wells in Russia, only the rotational drilling method is used. When using the rotary drilling method, a well is drilled with a rotating bit, while the drilled rock particles during the drilling process are carried to the surface by a continuously circulating stream of drilling fluid or air or gas injected into the well. Depending on the location of the engine, rotary drilling is divided into rotary drilling and turbo drilling. In rotary drilling, the rotator is located on the surface, causing the bit to rotate at the bottom using a string of drill pipes, the rotation speed is 20-200 rpm. When drilling with a downhole motor (turbo drill, screw drill or electric drill), torque is transmitted from a downhole motor installed above the bit.

The drilling process consists of the following main operations: lowering drill pipes with a bit into the well to the bottom and lifting drill pipes with a spent bit from the well and operating the bit at the bottom, i.e., destruction of the drilling rock. These operations are periodically interrupted to lower casing pipes into the well in order to protect the walls from collapses and separate oil (gas) and water horizons. At the same time, during the process of drilling wells, a number of auxiliary works are carried out: core sampling, preparation of drilling fluid (drilling fluid), logging, measuring curvature, well development in order to cause an influx of oil (gas) into the well, etc.

Figure 1 shows the technological diagram of the drilling rig.

Figure 1. Diagram of a drilling rig for rotary drilling: 1 - traveling rope; 2 - traveling block; 3 - tower; 4 - hook; 5 - drilling hose; 6 - leading pipe; 7 - gutters; 8 - mud pump; 9 - pump motor; 10 - pump piping; 11 - receiving tank (capacity); 12 - drill joint; 13 - drill pipe; 14 - hydraulic downhole motor; 15 - chisel; 16 - rotor; 17 - winch; 18 - winch and rotor motor; 19 - swivel

A drilling rig is a set of machines and mechanisms designed for drilling and securing wells. The drilling process is accompanied by lowering and raising the drill string, as well as maintaining it in weight. To reduce the load on the rope and reduce engine power, lifting equipment is used, consisting of a tower, a drilling drawworks and a traveling system. The traveling system consists of a fixed part of the crown block installed at the top of the tower canopy and a moving part of the traveling block, traveling rope, hook and slings. The traveling system is designed to convert the rotational movement of the winch drum into the translational movement of the hook. The drilling derrick is designed for raising and lowering the drill string and casing into the well, as well as for holding the drill string suspended during drilling and uniformly feeding it and placing the traveling system, drill pipes and part of the equipment in it. Hoisting operations are carried out using a drill winch. The drawworks consists of a base on which the winch shafts are fixed and connected to each other by gears, all shafts are connected to the gearbox, and the gearbox in turn is connected to the engine.

Land drilling equipment includes a receiving bridge designed to lay drill pipe and move equipment, tools, materials and spare parts along it. A system of devices for cleaning the flushing solution from drilled rock. And a number of auxiliary structures.

The drill string connects the drill bit (rock cutting tool) to the surface equipment, i.e., the drilling rig. The top pipe in a drill string is square and can be hexagonal or grooved. The drive tube passes through the hole in the rotor table. The rotor is placed in the center of the derrick. The leading pipe is connected at its upper end to a swivel designed to ensure rotation of the drill string suspended on a hook and supply flushing fluid through it. The lower part of the swivel is connected to the kelly and can rotate with the drill string. The top of the swivel is always stationary.

Let's consider the technology of the drilling process (Figure 1). A flexible hose 5 is connected to the hole of the stationary part of the swivel 19, through which the washing liquid is pumped into the well using drilling pumps 8. The washing liquid passes along the entire length of the drill string 13 and enters the hydraulic downhole motor 14, which causes the motor shaft to rotate, and then the liquid enters the bit 15. Coming out of the holes of the bit, the liquid washes the bottom, picks up particles of the drilled rock and, together with them, rises upward through the annular space between the walls of the well and the drill pipes and is directed to the pump intake. At the surface, the drilling fluid is cleaned of drilled rock using special equipment, after which it is again fed into the well.

Technological process drilling largely depends on the drilling fluid, which, depending on the geological features of the field, is prepared at water based, petroleum based, using a gaseous agent or air.

Conclusion. From the above it is clear that the technologies for the behavior of drilling processes are different, but the one suitable for the given conditions (depth of the well, the rock that composes it, pressure, etc.) must be selected based on geological and climatic conditions. Since, the further operational characteristics of the well, namely its flow rate and productivity, depend on the high-quality opening of the productive horizon in the field.

Bibliography:

1. Vadetsky Yu.V. Drilling oil and gas wells: a textbook for beginners. prof. education. M.: Publishing center "Academy", 2003. - 352 p. ISB# 5-7695-1119-2.

2. Vadetsky Yu.V. Driller's Handbook: textbook. guide for beginners prof. education. M.: Publishing center "Academy", 2008. - 416 p. ISB# 978-5-7695-2836-1.

Initially, our country used drilling for the construction of salt wells. Information about drilling wells for oil exploration dates back to the 30s of the 19th century in Taman. At the suggestion of mining engineer N.I. Voskoboynikov, in 1848, a well was drilled on Bibi-Heybat using a drill, from which oil was obtained. It was the first oil well in the world to be constructed by drilling using a method of continuously clearing the drilled rock from the well using fluid flushing.

Wells are drilled vertical, inclined, horizontal. The method of directional cluster drilling has become widely used, when 15 or more wells are drilled using an inclined method from one site. This method is successfully used in wetlands, when drilling wells from offshore drilling platforms, to preserve fertile arable land, etc.

Concept of a well

A well is a mine working (vertical or inclined) of circular cross-section, with a depth of several meters to several kilometers, of various diameters, constructed in the thickness of the earth’s crust. The top of the well is called the mouth, the bottom of the well is called the bottom, and the side is called the wellbore. The distance from the wellhead to the bottom along the axis of the wellbore is called the well length. The projection of the length onto the vertical axis is called the well depth.

Wells can be oil, gas, gas condensate, injection, observation, appraisal, etc. The design of wells must meet the following requirements:

• 1. Ensure the mechanical stability of the wellbore walls and reliable separation of all (oil, gas, water) layers from each other, free access to the bottom of the wells for lowering equipment, and prevention of rock collapse in the wellbore.
• 2. Effective and reliable connection of the well bottom with the productive (oil or gas) formation.
• 3. The possibility of sealing the wellhead and ensuring the direction of the extracted product into the system for collecting, preparing and transporting oil and gas or injecting an impact agent into the formation.
• 4. Possibility of carrying out research work in wells, as well as various geological, technical and maintenance work.

The stability of the wellbore walls and the separation of layers from each other is achieved by drilling and lowering several pipes into the well, called casing. First, the well is drilled to a depth of 50-100 meters, a steel pipe is lowered into it (1 = 500 mm or more - direction. The space between the outer wall of the pipe and the wall of the well (rock) is filled with a special cement mortar under pressure in order to prevent the collapse of the upper rocks and flows between the upper layers. Then the well is drilled with a smaller bit diameter to a depth of 500-600 m, a pipe with a diameter of 249-273 mm is lowered into it and cemented, as well as the direction, to the mouth. This string of pipes is called a conductor and is designed to prevent erosion of the upper layers, and also to create a channel for drilling clay mud. After this, the well is drilled to the design bottom. A production string (steel pipe with a diameter of 146-168 mm) is lowered into it, and the space between the pipe and the rock is filled under pressure with cement slurry to the mouth. Volume of cement slurry its injection pressure is determined by calculation.After the cement mortar hardens (usually 48 hours), a cement stone is formed in the interpipe space between the outer wall of the pipe and the rock, which separates the layers from each other.

Depending on the characteristics of the deposit, its reservoir pressure, geological section, etc., the well design can be single-column or multi-column (two or three). The last column is called the production column.

After completion of drilling, lowering of the production casing, its cementation in the well in the interval of the oil or gas formation, through holes are made through a steel pipe and cement stone using special perforators.

After this, the well is developed and put into operation. The well can have a closed or open bottom. An open face is used when the productive formation is composed of dense rocks - carbonate, calcareous or dense sandstones. With an open bottom hole, the well is drilled to the top of the productive formation, the production casing is lowered and cemented. Then, using a bit of a smaller diameter, the productive formation is opened (drilled) through the production casing. In this case, perforation is not required, because the productive formation is not blocked by a metal pipe.

If the productive formation consists of unstable and weakly cemented sandstones or limestones, then the bottom of the well is equipped with a closed one. In this case, the well is drilled to the design depth (a so-called “sump” is created slightly below 15-20 m of the productive formation), a production string is lowered into it, which is cemented, and then the productive sections of the formation are perforated to communicate the formation with the bottom of the well. If the formation is represented by weakly cemented sandstones or siltstones, then the productive formation can be opened with an open bottom, followed by lowering the liner filter. The filter is represented as holes in the production string in the productive formation interval.

Methods of drilling oil and gas wells.

There are several drilling methods, but mechanical drilling has found industrial use. Mechanical drilling is divided into impact and rotary. When percussion drilling, the drilling tool consists of a bit 1, a hammer rod 2, a rope lock 3. A mast 12 is installed on the well being drilled, which has a block 5 in the upper part, a balancer pulley roller 6, an auxiliary roller 8 and a drilling machine drum 11. The rope is wound on drum 11 of the drilling rig. The drilling tool is suspended on a rope 4, which is thrown over the block 5 of the mast 12. When the gears 10 rotate, the connecting rod 9, performing a reciprocating movement, raises and lowers the balancing frame 6. When the frame is lowered, the pulley roller 7 pulls the rope and lifts the drilling tool above the bottom of the well . When the frame is raised, the rope lowers, the bit falls onto the face and destroys the rock. To clean the face of destroyed rock (sludge), the drilling tool is lifted from the well and a bailer (an elongated bucket-type cylinder with a valve in the bottom) is lowered into it. To increase the efficiency of percussion-rope drilling, it is necessary to promptly clean the bottom of the well from drilled rock.

Rotary drilling.

Oil and gas wells are currently drilled using the rotary drilling method. During rotary drilling, rock destruction occurs due to a rotating bit. Under the weight of the tool, the bit enters the rock and, under the influence of torque, destroys the rock. Torque is transmitted to the bit using a rotor installed at the wellhead through the drill string. This drilling method is called rotary drilling. If torque is transmitted to the bit from a downhole motor (turbo drill, electric drill), then this method is called turbine drilling.

A turbodrill is a hydraulic turbine driven into rotation by means of flushing fluid pumped into the well by pumps.

The electric drill is a sealed electric motor, electricity it is supplied to it via a cable from the surface.

A drilling derrick is a metal structure above a well for lowering and lifting a drilling tool with a bit, downhole motors, casing pipes, placing drill stands after they are lifted from the well, etc.

Towers are available in several modifications. The main characteristics of towers are lifting capacity, height, “magazine” capacity (space for drill pipe plugs), dimensions of the lower and upper bases, weight (mass of the tower).

The lifting capacity of the tower is the maximum, maximum permissible load on the tower during the drilling process. The height of the tower determines the length of the candle that can be removed from the well, the length of which determines the duration of tripping operations.

For drilling wells to a depth of 400-600 m, a tower with a height of 16-18 m is used, for a depth of 2000-3000 m - a height of 42 m, and for a depth of 4000 to 6500 m - 53 m. The capacity of the “magazine” shows the total length of the drilling pipes with a diameter of 114-168 mm can be placed in them. The dimensions of the upper and lower foundations characterize the conditions of the drilling crew, taking into account the placement of drilling equipment, drilling tools and means of mechanization of hoisting operations. The dimensions of the upper base of the towers are 2x2 or 2.6x2.6 m, and the bottom - 8x8 or 10x10 m.

The total mass of drilling rigs is tens of tons.

Well construction cycle.

Before drilling begins at the well site, the site is cleared of foreign objects; if there is forest, it is cut down and uprooted. If drilling will be carried out in a swampy area, then first fill the road to the drilling site, and also fill the site, eliminating the swamp, under the drilling rig. They plan the site, install power lines, communications and water conduits.

Drilling derricks, if the terrain and distance allow, are transported without disassembly on special tracked carts or on sleds with runners, and the pneumatic movement method is also possible. After transportation and installation of the drilling rig at the site, installation of the remaining equipment begins, i.e. installation of diesel driven piston pumps or electric driven pumps; drilling mud cleaning system, electrical room, wellhead equipment (rotor, preventer, hydraulic weight indicator), drilling shelter for above-ground structures, etc. If drilling starts at new square, remote from the place of drilling operations, in this case all equipment, including the drilling rig, pumping unit, treatment facilities, etc., is delivered disassembled to the drilling site and here they begin to assemble the drilling rig and all other equipment.

After installing the drilling rig and all equipment, preparatory work for drilling the well begins.

Preparatory work includes:

• 1. Equipping the traveling block and crown block with steel rope and suspending the lifting hook.
• 2. Installation and testing of small-scale mechanization equipment.
• 3. Assembling and hanging a square swivel (drive pipe) to the hook, connecting a flexible high-pressure hose to the riser pipe and to the swivel.
• 4. Tower alignment.
• 5. Installation of the rotor.
• 6. Drilling the direction of the well.

Wells are drilled vertical, directional and horizontal. For a long time, the main type of well drilling was vertical drilling. In recent years, the method of directional drilling has increasingly begun to be used, i.e. when, according to drilling plans, the well is drilled along a trajectory with a deviation from the vertical. Typically, it is advisable to drill inclined wells under the bottom of the sea, river, lake, as well as under mountains and ravines; in swampy areas, protected forests, for large industrial facilities, cities and villages. Inclined wells are also used in the elimination of open oil and gas gushers, as well as for the purpose of preserving fertile lands, in order to reduce the cost of drilling wells by reducing preparatory work and communications (communications, electricity, water pipelines, etc.). To deviate the well profile from the vertical, special devices are used. These include: crooked sub, crooked drill pipe, various types diverters, etc. More and more in our country in recent years, horizontal drilling of wells and drilling of horizontal lateral wellbores in depleted and unprofitable wells where there are undeveloped layers with oil are used.

Well perforation. After the casing pipes are lowered into the well and cemented, holes are made in the production casing and cement stone against the productive part of the formation using perforators to connect the productive part of the formation with the bottom of the well. This operation is called perforation. Apply various methods well perforation: bullet, torpedo, cumulative and hydrosandblasting.

A bullet perforator (PP) is a pipe 1 m long and 100 mm in diameter, which is loaded with compressed gunpowder and 10 steel bullets. On a logging cable, a bullet perforator is lowered into a well filled with clay solution, installed against a given interval of the productive formation, and shots are fired. The depth of the holes in the rock does not exceed 5-7 cm. Many bullets get stuck in the production column, in the cement stone, and only a small number of them pierce the column and cement stone. It is practically not used at present.

Torpedo perforator (TP). Torpedo perforation is carried out by devices lowered on a cable and firing explosive shells with a diameter of 22 mm. The apparatus consists of sections, each of which has two horizontal trunks. The projectile is equipped with a pin-type detonator. When the projectile stops, the internal charge explodes and the surrounding rock cracks. The depth of the channels, according to test data, is 100-160 mm, the diameter of the channel is 22 mm. No more than four holes are made per 1 m of productive part of the formation, since torpedo perforation often causes destruction of the casing. Just like bullet, torpedo perforation is used very limitedly.

Currently, cumulative perforation (PC) is mainly used. Cumulative perforators have charges with a conical recess, which allow you to focus explosive gas flows and direct them with high speed perpendicular to the walls of the well.

A block of compressed powdered explosive material, which has a conical recess lined with a metal die, is inserted into a cumulative perforator.

Cumulative perforation is carried out by firing perforators that do not have bullets or shells. The penetration of the column, cement stone and rock is achieved through a focused explosion. This focusing is due to the conical shape of the surface of the explosive charge, lined with a thin metal coating (copper sheet 0.6 mm thick). The energy of the explosion in the form of a thin beam of gases - lining products - pierces the channel. The cumulative jet has a speed at the head of up to 6-8 km/s and creates a pressure of 3-5 thousand MPa.

When fired with a shaped charge, a narrow perforation channel with a depth of up to 350 mm and a diameter in the middle part of 8-14 mm is formed in the column and cement stone.

In oil fields, a hydrosandblasting perforator (GSP) is also used.

A hydrosandblasting hammer consists of a thick-walled body into which up to ten nozzles made of abrasive-resistant material (ceramics, hard alloys) with hole diameters of 3-6 mm are screwed.

A hydrosand-jet perforator is lowered into the well using pump and compressor pipes. Before perforating a well, a ball is thrown from the surface into the tubing, which blocks the through hole of the perforator. After this, using pumping units AN-500 or AN-700, liquid with sand is pumped into the well through the tubing. The injected liquid with sand comes out only through the nozzles. When leaving the nozzles, enormous speeds of the abrasive jet develop. As a result, in a short time, holes are made in the casing pipes, cement stone and rock, and the wellbore is connected to the productive formation. Depending on the diameter of the nozzles, their number and the speed of liquid injection, the depth of the perforations reaches 40-60 cm. At the same time, the tightness of the cement stone behind the column is maintained. During hydrosandblast perforation, a pressure of up to 40 MPa is created at the wellhead. The pumping rate of liquid with sand is 3-4 l/s per nozzle. In this case, the volumetric velocity of the jet in the nozzle reaches 200-300 m3/day, and the pressure drop is 18-22 mPa. The duration of perforation of one interval is 15-20 minutes. Upon completion of perforation of a given interval, the perforator is raised and placed at the next interval, and the operation is repeated.

call inflow into the well.

In field practice, the following methods are used to cause an influx of liquid from the productive formation to the bottom of the well: tarting, pistoning, replacing the liquid in the well with a lighter one, the compressor method, pumping a gas-liquid mixture, pumping with deep-well pumps. Before the well is developed, fittings are installed at the wellhead. In any case, a high-pressure valve must be installed on the casing flange to shut off the wellbore in emergency situations.

Pistoning. When pistoning (swabbing), the piston, or swab, is lowered into the tubing at steel rope. The piston (swab) is a pipe with a diameter of 25-37.5 mm with a valve at the bottom that opens upward. Rubber cuffs (3-4 pieces) reinforced with wire mesh are installed on the outer surface of the pipe (at the joints). When the swab is lowered below the level, the liquid in the well flows through the valve into the space above the piston. When the swab is lifted, the valve closes, and the cuffs, expanded by the pressure of the liquid column above them, are pressed against the walls of the tubing and compacted. During one lift, the piston carries out a column of liquid equal to the depth of its immersion under the liquid level. The immersion depth is limited by the strength of the tartar rope and is usually 100-150 m.

Tartanization is the extraction of liquid from a well with a bailer lowered on a steel (16 mm) rope using a winch on a tractor (car). A bailer is made from a pipe 7.5-8 m long, which has a valve in the lower part with a rod that opens when the rod is pressed against it. At the top of the bailer there is a bracket for fastening the rope. The bailer diameter should not exceed 0.7 of the casing diameter. During one run, the bailer removes liquid from the well with a volume of no more than 0.06 m3.

Tartanning is a labor-intensive and low-productivity method. At the same time, tarting makes it possible to extract clay solution from the bottom and control the fluid level in the well. Repeated lowering and raising of the piston leads to a gradual decrease in the liquid level in the well. The big disadvantage of this method is that you have to work with an open mouth, which is associated with the danger of liquid release and open gushing. Therefore, piston is used mainly in the development of injection wells.

Replacing fluid in the well. A well completed by drilling is usually filled with clay mud. If we replace the clay solution in the well with water or degassed oil, we will reduce the bottomhole pressure. This method is used to develop wells with high reservoir pressure and good reservoir properties.

Compressor method of development. The compressor method is more widely used in well development. Before development, pump and compressor pipes are lowered into the well, and the wellhead is equipped with a Christmas tree. A mobile compressor or a high-pressure gas line from a gas compressor station is connected to the interpipe space through a discharge pipeline. When gas is injected into the well, the liquid in the annulus is pushed to the tubing shoe or to the starting hole (3-4 mm) in the tubing, made in advance at a depth of 700-800 m from the wellhead, and breaks through into the tubing. Gas entering the tubing aerates the liquid in them. As a result, the pressure at the bottom is significantly reduced. By adjusting the gas flow, they change the density of the gas-liquid mixture in the pipes, and, accordingly, the pressure at the bottom of the well. When the bottomhole pressure is below reservoir pressure, the influx of liquid and gas into the well begins. After receiving a stable inflow, the well is transferred to a stationary operating mode. This method allows you to relatively quickly obtain significant drawdowns on the formation, which is especially important for effective cleaning of the wellbore zone. In conditions of hard rocks (sandstones, limestones), this leads to intensive cleaning of the pore space from calmatizing (clogging) material, and in conditions of loose rocks - to the destruction of the bottom-hole zone of the formation. To ensure a smoother start-up of the well, aerated oil is pumped through the annulus using a compressor, a washing unit and a mixer. After the gas-liquid mixture is released through the flow line into the receiving tank, the supply of aerated oil is gradually reduced until it stops completely.

Development of wells with compressed air is mainly carried out using mobile compressors UKP-80 or KS-100. The UKP-80 compressor develops a pressure of 8 MPa with an air supply of 8 m3/min, and the KS-100 develops a pressure of 10 MPa with an air supply of 16 m3/min. It should be noted that when developing wells with compressed air, explosions are possible, since when the content of hydrocarbon gas in a mixture with air is from 6 to 15%, an explosive mixture is formed.

Development of wells by injection of carbonated liquid.

Well completion with carbonated liquid involves pumping a mixture of gas and liquid (water or oil) into the annulus instead of gas or air. The density of such a gas-liquid mixture depends on the ratio of the flow rates of injected gas and liquid, which allows you to adjust the parameters of the development process. Taking into account the fact that the density of the gas-liquid mixture is greater than the density of pure gas, this method makes it possible to develop deep wells with compressors that create lower pressure.

Development of injection wells. Injection wells must have high injectivity throughout the entire thickness of the productive formation. This can be achieved by good cleaning of the bottomhole zone of the productive formation from dirt and other calmatizing materials. The bottomhole zone of the formation is cleaned before launching an injection well for injection using the same methods as during the development of oil production wells, but drainage of the bottomhole zones of the formation takes much longer. The duration of flushing reaches one day or more and depends on the amount of mechanical impurities contained in the water leaving the well. The content of mechanical impurities at the end of washing should not exceed 10-20 mg/l.

Maximum cleaning of the pore space of the near-wellbore zone of the formation occurs using drainage methods that make it possible to create very high depressions in the formation, ensuring high rates of fluid filtration to the bottom of wells under unsteady conditions. Most often, formation drainage is carried out using self-discharge methods, liquid aeration, pumping using high-performance submersible centrifugal pumps, etc.

When developing injection wells, the variable pressure method (VPM) has become widely used. When using this method, high injection pressure is periodically created into the bottomhole zone of the formation through tubing using pumping units for a short time, which is then abruptly released through the annulus (a “discharge” is carried out). When fluid is injected at high pressure in the near-wellbore zone of the formation, existing cracks open and new ones form, and when the pressure is released, fluid flows to the bottom at high speed. Good results are obtained when using the method of periodic drainage of bottomhole zones by creating multiple instantaneous high depressions at the bottom.

Sometimes poor injectivity of injection wells occurs either due to the low natural permeability of the formation rocks, or large quantity clayey interlayers, which cannot be developed by drainage of the bottomhole zones. In such cases, to increase the injectivity of injection wells, other methods of influence are used, which make it possible to increase the diameters of filtration channels or create a system of cracks in the formation rocks. Such methods include various acid treatments, thermal methods, hydraulic fracturing, crevice unloading, oxidation treatment of the formation, etc.