Modern technologies for drilling oil and gas wells. What is an oil well? Oil drilling process - video
Mining is extraction from the bowels of the earth natural resources... The development of solid minerals is carried out by open-cut or mine method. Wells are drilled to extract liquid and gaseous natural resources. Modern well drilling technologies allow the development of oil and gas fields at a depth of over 12,000 meters.
The importance of hydrocarbon production in modern world hard to overestimate. Fuel is made from oil (see) and oils, rubbers are synthesized. The petrochemical industry produces household plastics, dyes and detergents. For countries of oil and gas exporters, fees from the sale of hydrocarbons abroad is a significant, and often the main method of replenishing the budget.
Exploration of deposits, installation of drilling rigs
A geological survey is carried out at the proposed location of the mineral deposits and a location for a research well is determined. Within a radius of 50 meters from the exploration well, the site is leveled and an oil rig is mounted. The diameter of the research well is 70-150 mm. During the drilling process, samples of drill cuttings are taken from different depths for subsequent geological exploration. Modern complexes for geological research make it possible to accurately answer the question of whether it is worth starting the production of energy resources through this well on an industrial scale.
When geological exploration of drill cuttings has shown the promise of industrial development, the construction of a drilling site begins. The previously cleared area is concreted and fenced, a grader road is laid (unpaved road). A tower is being built on the created one, a winch, mud pumps are mounted, a generator and everything necessary are installed. The assembled equipment is tested, gradually bringing it to the planned capacity, and put into operation.
Most often used technology mechanical drilling of wells, which is carried out in a rotational, percussion or combined way. The drill is attached to the square drill string and is lowered into the borehole with the help of a traveling system. A rotor located above the wellhead transfers rotary motion to the drill.
As the well is drilled, the drill string grows. Simultaneously with the process of drilling a production well with the help of special pumps, work is carried out to flush the well. To flush the well from particles of destroyed rock, a flushing fluid is used, which can be industrial water, aqueous suspension, clay solutions or hydrocarbon-based solutions. After pumping out the drilling fluid into special containers, it is cleaned and used again. In addition to cleaning the bottom hole from cuttings, the drilling fluids provide cooling of the drill, reduce the friction of the drill string against the borehole walls and prevent collapse.
At the final stage of drilling, the production well is cemented.
There are two cementing methods:
- Direct method- the solution is pumped into the drill string and pushed into the annulus.
- Reverse method- the solution is pumped into the annulus from the surface.
A number of specialized machines and mechanisms are used for drilling wells. On the way to design depth, there are often areas of rock with increased hardness. To pass them, it is necessary to put an additional load on the drill string, therefore, quite serious requirements are imposed on the production equipment.
The rig equipment is not cheap and is designed for long-term use. If production stops due to a breakdown of any mechanism, it will be necessary to wait for a replacement, which will seriously reduce the profitability of the enterprise. Equipment and mechanisms for hydrocarbon production must be made of high quality and wear-resistant materials.
The drilling platform equipment can be divided into three parts:
- Drilling part- drill and drill string.
- Power section- rotor and tackle system, which ensure drill string rotation and tripping manipulations.
- Auxiliary part- generators, pumps, containers.
Uninterrupted operation of the drilling rig depends on the correct operation of the equipment and Maintenance mechanisms in the terms prescribed by the manufacturer. It is equally important to change consumable parts in a timely manner, even if appearance everything is fine with them. Without observance of operating rules, it is impossible to guarantee the safety of the drilling platform personnel, avoidance of environmental pollution and uninterrupted production of oil or gas.
Methods for drilling production wells
Well drilling methods are divided depending on the method of impact on the rock.
Mechanical:
- Shock.
- Rotational.
- Combined.
Non-mechanical:
- Hydraulic fracturing.
- High temperature exposure.
- Undermining.
It should be noted that the main drilling method is rotary and rotary-percussion, other methods are rarely used in practice.
Name: Technique and technology for drilling oil and gas wells
Format: PDF
Size: 14.1 Mb
Year of publication: 2003
Foreword
PART 1. TECHNOLOGY OF DRILLING OIL AND GAS WELLS
Chapter 1. Fundamentals of oil and gas field geology
1.1. The composition of the earth's crust
1.2. Geochronology of rocks
1.3. Sedimentary rocks and forms of their occurrence
1.4. Formation of oil and gas deposits
1.5. Physical and chemical properties of oil and gas
1.6. Prospecting and exploration of oil and gas fields
1.7. Drawing up a geological section of a well
1.8. Composition and mineralization of groundwater
1.9. Well testing
Chapter 2. General concepts of well construction
2.1. Basic concepts and definitions
2.2. Geological substantiation of the location and design of the well as an engineering structure
2.3. Installation of equipment for well construction
2.4. Wellbore drilling
2.5. Drill bits
2.6. Drill string
2.7. Bit drive
2.8. Features of drilling wells in water areas
2.9. Well casing and reservoir isolation
Chapter 3. Mechanical properties of rocks
3.1. General Provisions
3.2. Mechanical and abrasive properties of rocks
3.3. Influence of all-round pressure, temperature and water saturation on some properties of rocks
Chapter 4. Drill bits
4.1. Roller cone bits
4.2. Kinematics and dynamics of roller cone bits
4.3. Diamond chisels
4.4. Blade chisels
Chapter 5. Operation of the drill string
5.1. Drill string physical model
5.2. Drill string stability
5.3. Stresses and loads in drill pipe
Chapter 6. Well flushing
6.1. Terms and Definitions
6.2. Well flushing process functions
6.3. Requirements for drilling fluids
6.4. Drilling fluids
6.5. Preparation and cleaning of drilling fluids
6.6. Drilling fluid chemical treatment technology
6.7. Hydraulic calculation of well flushing with incompressible fluid
6.8. Disposal methods for waste drilling fluids and drill cuttings
6.9. Methods for neutralizing waste drilling fluids and cuttings
Chapter 7. Complications during drilling, their prevention and control
7.1. Classification of complications
7.3. Liquid losses in wells
7.4. Gas-oil-water showings
7.5. Tacking, tightening and seating of the pipe string
Chapter 8. Drilling Modes
8.1. Introductory concepts
8.2. Influence of various factors on the drilling process
8.3. The influence of differential and oppressive pressures on the destruction of rocks
8.4. Rational bit development
8.5. Drilling regime design
8.6. Cleaning a drilled well from cuttings
Chapter 9. Drilling directional and horizontal wells
9.1. Goals and objectives of directional well drilling
9.2. Directional Well Design Basics
9.3. Bottomhole Trajectory Factors
9.4. Downhole assemblies for directional drilling
9.5. Well trajectory control methods and devices
9.6. Features of drilling and navigation of horizontal wells
Chapter 10. Opening and drilling of productive strata
10.1. Reservoir drilling
10.2. Technological factors ensuring drilling and opening of a productive formation
10.3. Change in the permeability of the bottomhole formation zone. Completion drilling fluids
10.4. Formation testing and well testing while drilling
Chapter 11. Well structures. Filters
11.1. Well Design Basics
11.2. Well bottom structures
Chapter 12. Well casing and reservoir isolation
12.1. Wellbore preparation
12.2. Well casing technology
12.3. Oil well cements and mortars
12.4. Well cementing calculation
Chapter 13. Re-opening of productive formations, stimulation of oil (gas) and
well development
13.1. Bullet perforation
13.2. Cumulative perforation
13.3. Underbalanced perforation
13.4. Perforation during repression
13.5. Special solutions for well perforation
13.6. Buffer delimiters
13.7. Well filling technology with special fluid
13.8. Inflow induction by replacing fluid in the production casing
13.9. Inflow call with air cushion
13.10. Inflow call using start valves
13.11. Inflow call with jet devices
13.12. Interval lowering of the fluid level in the well
13.13. Reducing the liquid level in the well by pistoning (swabbing)
13.14. Calling inflow from the reservoir using aeration method
13.15. Decrease in fluid level in the well under conditions of abnormally low reservoir pressure
13.16. Reservoir induction using two-phase foams
13.17. The technology of causing inflow from the formation with foams using ejectors.
13.18. Reservoir Induction with Test Tool Kits
13.19. Application of gaseous agents for well development. Well completion with nitrogen
PART 2. TECHNIQUE OF DRILLING OIL AND GAS WELLS
Chapter 14. Drilling rigs
14.1. Requirements for drilling rigs
14.2. Classification and characteristics of installations
14.3. Complete drilling rigs for production and deep exploration drilling.
14.4. Selection of the type and main parameters of the drilling rig
14.5. Selection of the scheme and layout of the drilling rig equipment
14.6. Requirements for the kinematic diagram of the drilling rig
14.7. Drilling rigs manufactured by OJSC "Uralmagnzavod"
14.8. Drilling rigs manufactured by JSC "Volgograd Drilling Equipment Plant"
Chapter 15. Launching complex
15.1. The process of lifting and lowering columns. Complex functions
15.2. Kinematic diagram of the complex for SPO
15.3. Talon system
15.4. Selection of steel ropes for tackle systems
15.5. Crown blocks and traveling blocks
15.6. Drilling hooks and hook blocks
15.7. Tackle mechanisms of drilling rigs of OJSC "Uralmagnzavod"
15.8. Travel mechanisms of VZBT drilling rigs
15.9. Drilling hooks
15.10. Drawworks
15.11. Drawworks brake systems
15.12. The volume of tripping operations
15.13. Hoist kinematics
15.14. Lifting dynamics
Chapter 16. Equipment for well flushing system
16.1. Mud pumps
16.2. Manifold
16.3. Swivel
Chapter 17. Surface circulation system
17.1. Parameters and completeness of circulation systems
17.2. Circulation system blocks
17.3. Stirrers
17.4. Equipment for cleaning drilling mud from cuttings
17.5. Drilling fluid degassers
17.6. Centrifuge Mud Treatment Plant
17.7. Suction Lines for Mud Pumps
Chapter 18. Rock-cutting tools: drill bits, drill heads,
expanders, calibrators
18.1. Roller cone bits
18.2. Blade chisels
18.3. Milling bits
18.4. Chisels ISM
18.5. Diamond chisels
18.6. Roller cone drill heads
18.7. Blade and milling carbide drill heads
18.8. Diamond drill heads and ISM drill heads
18.9. Core receiving tool
18.10. Extenders
18.11. Calibrators-centralizers
Chapter 19. Drill pipes. Drill string design
19.1. Kelly pipes
19.2. Upset drill pipes and couplings
19.3. Upset drill pipe locks
19.4. Drill pipes with welded tool joints
19.5. Light alloy drill pipes
19.6. Drill collars
19.7. Drill String Subs
19.8. General principles and methodology for calculating the layout of drill pipes in the string
Chapter 20. Bit Drive: Drill Rotors, Downhole Motors
20.1. Drilling rotors
20.2. Turbodrills
20.3. Downhole motors
20.4. Downhole turboprop motors
20.5. Electric drills
Chapter 21. Wellhead equipment of drilled wells
21.1. Column heads
21.2 Blowout prevention equipment
Chapter 22. Casing pipes. Calculation of casing strings
22.1. Casing pipes and couplings for them
22.2. Calculation of casing strings
Chapter 23. Power drive of the drilling complex
23.1. Types of drives, their characteristics
23.2. Selection of power drive motors
23.3. Artificial adaptations for drives
23.4. Couplings
23.5. Chain drives of drilling rigs
23.6. Power units and engines of modern drilling rigs
23.7. Layout of power drives and transmissions
Chapter 24. Equipment for mechanization and automation of technological
processes
24.1. Bit feed automation
24.2. Descent and ascent automation (ASP)
24.3. Drilling tongs automatic stationary
24.4. Pneumatic wedge gripper
24.5. Auxiliary winch
Chapter 25. Equipment for drilling oil and gas wells at sea
25.1. Features of the development of offshore oil and gas fields
25.2. The main types of technical means for the development of offshore oil and gas fields
25.3. Floating drilling equipment (PBF)
25.4. Jack-up floating drilling rigs (jack-up rigs)
25.5. Semi-submersible floating drilling rigs (PPDR)
25.6. Drilling vessels (BS)
25.7. Drilling rigs for PBS
25.8. Subsea wellhead equipment
25.9. Retention systems for floating drilling equipment at the point of drilling
25.10. Offshore fixed platforms (SMP)
25.11. Environmental protection in offshore drilling
FEDERAL EDUCATION AGENCY
GOUVPO "UDMURTSK STATE UNIVERSITY"
Department of Economics, Management of the Oil and Gas Industry
On the topic "Drilling oil and gas wells"
Head Borkhovich S. Yu.
Questions for the test
1. Methods for drilling wells
1.1 Percussion drilling
1.2 Rotary drilling
2. Drill string. Main elements. Load distribution along the length of the drill string
2.2 Composition of the drill string
3. Purpose of drilling fluids. Technological requirements and restrictions on the properties of drilling fluids
3.1 Functions of the drilling fluid
3.2 Requirements for drilling fluids
4. Factors affecting the quality of well cementing
5. Types of drill bits and their purpose
5.1 Bit types for solid drilling
5.2 Roller-cone bits
5.3 Blade chisels
5.4 Milling bits
5.5 IMS bits
Literature
Questions for the test
Well drilling methods
Drill string. Main elements. Load distribution along the length of the drill string
Purpose of drilling fluids. Technological requirements and restrictions on the properties of drilling fluids
Factors affecting the quality of well cementing
Types of drill bits and their purpose
1 . Well drilling methods
Exists different ways drilling, but mechanical drilling became industrialized. It is subdivided into percussion and rotational.
1.1 Percussion drilling
Percussion drilling the drilling tool includes: chisel (1); shock rods (2); rope lock (3); A mast (12) is installed on the surface; block (5); balancer pull-off roller (7); auxiliary roller (8); drilling machine drum (11); rope (4); gears (10); connecting rod (9); balance frame (6). When the gears rotate, making movements, raising and lowering the balance frame. When the frame is lowered, the take-off roller lifts the drilling tool above the bottom of the hole. When the frame is lifted, the rope is released, the chisel falls into the bottomhole, thereby destroying the rock. In order to prevent the collapse of the walls of the well, the casing is lowered into it. This drilling method is applicable to shallow depths when drilling water wells. At the moment, the percussion method is not used for drilling wells.
1.2 Rotary drilling
Rotary drilling. Oil and gas wells are drilled by rotary drilling. With such drilling, the destruction of steam occurs due to the rotation of the bit. Rotation of the bit is provided by the rotor located at the wellhead through the string of drill pipes. This is called a rotary mode. Also, torque is sometimes created with the help of an engine (turbodrill, electric drill, downhole motor), then this method is called downhole drilling.
Turbodrill Is a hydraulic turbine driven into rotation by means of a drilling fluid pumped into the well.
Electric drill- is an electric motor, an electric current is supplied to it through a cable from the surface. Wells are drilled using a drilling rig.
1-chisel; 2 - overhead heavy-duty drill pipe; 3.8 - sub; 4 - centralizer; 5 - sleeve sub; 6.7 - heavy-weight drill pipes; 9 - safety ring; 10 - drill pipes; 11 - safety sub; 12.23 - rod subs, lower and upper; 13 - leading pipe; 14 - reducer; 15 - winch; 16 - swivel sub; 17 - hook; 18 - crown block; 19 - tower; 20 - traveling block; 21 - swivel; 22 - hose; 24 - riser; 25 - rotor; 26 - sludge separator; 27 - mud pump
The destruction is carried out with the help of a bit, which is run on drill pipes, to the bottom. Rotary motion is provided by a downhole motor through the drill string. After lowering the drill pipes with a bit, two liners are inserted into the bore of the rotor barrel, and inside them are two clamps, which form a square hole. In this hole, there is also a leading pipe, also of a square cross section. It receives torque from the rotor table and moves freely along the rotor axis. All running operations and holding the drill string on the weight are carried out by a hoisting mechanism.
2 Drill string. Main elements. Load distribution along the length of the drill string
2.1 Purpose of the drill string
The drill string is the link between the drilling equipment located on the day surface and the downhole tool (drill bit, formation tester, fishing tool, etc.) used at the moment in time to perform any technological operation in the wellbore.
The functions performed by the drill string are determined by the work carried out in the well. The main ones are the following.
During mechanical drilling, the drill string:
· Is a channel for supplying to the bottomhole the energy required for the rotation of the bit: mechanical - during rotary drilling; hydraulic - when drilling with hydraulic downhole motors (turbodrill, downhole screw motor); electric - when drilling with electric drills (through a cable located inside the pipes);
· Perceives and transfers to the borehole walls (at a small current depth of the borehole also to the rotor) reactive torque when drilling with downhole motors;
· Is a channel for the circular circulation of the working agent (liquid, gas-liquid mixture, gas); usually, the working agent moves down to the bottomhole along the in-pipe space, captures the destroyed rock (cuttings), and then moves up the annulus to the wellhead (direct flushing);
· Serves to create (by the weight of the lower part of the string) or transfer (when the tool is forced) the axial load on the bit, simultaneously taking on the dynamic loads from the working bit, partially damping and reflecting them back to the bit and partially letting them go higher;
· Can serve as a communication channel for receiving information from the bottom hole or transmitting control action to the downhole tool.
· During tripping operations, the drill string is used for lowering and lifting bits, downhole motors, various downhole assemblies;
· For the passage of downhole instrumentation;
For development of the wellbore, carrying out intermediate flushing with
the purpose of removing sludge plugs, etc.
When eliminating complications and accidents, as well as conducting research in the well and testing formations, the drill string serves:
· For pumping and blowing plugging materials into the formation;
· For running and installing packers in order to conduct hydrodynamic studies of formations by sampling or injection of fluid;
For lowering and installing overlaps in order to isolate absorption zones,
· Strengthening of zones of crumbling or landslides, installation of cement bridges, etc.;
· For lowering the fishing tool and working with it.
When drilling with coring (rock sample) with a removable coring pipe, the drill string serves as a channel through which the lowering and lifting of the coring pipe is carried out.
2.2 Composition of the drill string
The drill string (with the exception of the recent continuous pipes) is made up of drill pipes using a threaded joint. The connection of pipes to each other is usually carried out using special connecting elements - drill joints, although toolless drill pipes can also be used. When lifting the drill string (in order to replace a worn-out bit or when performing other technological operations), the drill string is disassembled each time into shorter links with the latter being installed inside the tower on a special platform - a candlestick or (in rare cases) on racks outside the drilling tower, and when downhill, she again gathers in a long column.
It would be inconvenient and irrational to assemble and disassemble the drill string with its disassembly into separate (single) pipes. Therefore, individual pipes are preliminarily (when building up the tool) assembled into so-called drill plugs, which are not subsequently disassembled (while the drilling is being carried out by this drill string).
A plug with a length of 24-26 m (at a drilling depth of 5000 m and more, drill plugs with a length of 36-38 m with a drill tower 53-64 m high can be used) is made of two, three or four pipes when using pipes with a length of 12, 8 and m, respectively In the latter case, for the sake of convenience, two 6-meter pipes are pre-connected by means of a coupling into a two-pipe (elbow), which cannot be further disassembled.
As part of the drill string directly above the bit or above the downhole motor, heavy-duty drill pipes (collars) are always provided, which, having a multiple of weight and stiffness compared to conventional drill pipes, allow creating the necessary load on the bit and provide sufficient rigidity of the bottom of the tool during avoidance of its buckling and uncontrolled borehole curvature. Drill collars are also used to control vibrations of the bottom of the drill string in combination with its other elements.
The drill string usually includes centralizers, calibrators, stabilizers, filters, often metal traps, check valves, sometimes special mechanisms and devices such as expanders, flywheels, downhole feed mechanisms, waveguides, resonators, longitudinal and torsional vibration dampers, tread rings that have an appropriate purpose.
For controllable curvature of the wellbore in a given direction or, on the contrary, for straightening an already curved wellbore, diverters are included in the drill string, and to maintain the straight-line direction of the wellbore, special, often quite complex, arrangements of the lower part of the drill string are used.
Well drilling is a complex technological process of introducing a heavy-duty drill hole into the earth's surface, which consists of a number of operations:
- introduction (deepening) of wells by layer-by-layer destruction of rock formations with a special powerful drilling tool;
- elimination of drilled rock from the well;
- strengthening the wellbore with the so-called casing strings;
- exploration of rocks using a number of geological and geophysical measures, determination of the course and direction of drilling;
- Descent to a predetermined depth and strengthening (cementing) of the finishing column.
For the first time in the world, an oil well was drilled in the middle of the 19th century, not far from the city of Baku, the depth of the first oil well was 21 meters
Experts distinguish four types of well drilling, based on their depth: shallow (up to 1.5 km), medium (up to 4.5 km), deep (up to 6 km) and superdeep (over 6 km).
An interesting fact: the Kola superdeep wells are considered the deepest oil well in the world, its depth is about 12.26 km. To date, the well is not being operated.
There are two ways of drilling by the type of rock destruction:
- mechanical (rotational, shock);
- non-mechanical (thermal, explosive, hydraulic, electrical impulse)
The mechanical method is the most common in our country, drilling companies use only it, more precisely, exclusively the rotational method.... During drilling, the rock is destroyed by powerful bits, the bottomhole is freed from the drilled rock by continuously circulating flows of drilling mud, sometimes a gaseous agent is used for flushing. It should be noted that all wells are drilled strictly vertically. But if nevertheless the need arises, directional drilling is also used..
Used drilling rigs and equipment
Drilling is carried out using special drilling rigs, professional drilling tools and complex equipment... A drilling rig is a whole complex of specialized ground equipment used to perform well creation and maintenance of the drilling process itself. The rig consists of: an oil rig, equipment for tripping operations, ground equipment, an offshore structure, a power drive, a drilling fluid supply system... The success of the technological process largely depends on the quality of the drilling fluid, which is prepared on a water or oil base.
Today, in the world, and in particular in Russia, there are several large factories engaged in the manufacture of drilling equipment.... Among which:
Azneftekhimmash OJSC (Azerbaijan), Lugansk Machine Tool Plant Production Association (Ukraine), ALTAIGEOMASH LLC (Russia), Drilling Equipment Plant (Volgograd, Russia).
Video
Theme: Drilling oil and gas wells.
Plan: 1. General information about oil and gas operations.
2. Methods for drilling wells.
3. Classification of wells.
1. General information about oil and gas operations.
Well drilling is the process of constructing directional mine workings of great length and small (compared to length) diameter. The beginning of the well on the surface of the earth is called the wellhead, the bottom is called the bottomhole. This process - drilling - is common in various sectors of the national economy.
Aims and objectives of drilling
Oil and gas are extracted using wells, the main construction processes of which are drilling and casing. It is necessary to carry out high-quality well construction in ever-increasing volumes with a multiple reduction in the timing of their drilling, as well as with a decrease in labor and energy intensity and capital costs.
Well drilling is the only method of efficient development, incremental production and oil and gas reserves.
The cycle of construction of oil and gas wells prior to their commissioning consists of the following successive links:
boring a wellbore, the implementation of which is possible only when performing parallel work of two types - deepening the bottom through local destruction of rock and cleaning the well from destroyed (drilled) rock;
separation of layers, consisting of sequential works of two types - securing the walls of the borehole with casing pipes connected to the casing, and sealing (cementing, plugging) the annular space;
well development as a production facility.
2. Methods for drilling wells.
The common methods of rotary drilling - rotary, turbine and electric drilling - involve the rotation of the working tool that destroys the rock - the bit. The destroyed rock is removed from the well by pumping into the pipe string and exiting through the annulus with drilling fluid, foam or gas.
Rotary drilling
In rotary drilling, the bit rotates with the entire drill string; rotation is transmitted through the working tube from the rotor connected to power plant transmission system. The weight on the bit is generated by a fraction of the weight of the drill pipe.
In rotary drilling, the maximum string torque depends on the rock resistance to bit rotation, the friction resistance of the string and rotating fluid against the borehole wall, as well as on the inertial effect of elastic torsional vibrations.
In the world drilling practice, the rotary method is the most widespread: almost 100% of the volume of drilling operations in the USA and Canada is performed by this method. V last years there is a tendency to increase the volume of rotary drilling in Russia, even in the eastern regions. The main advantages of rotary drilling over turbine drilling are the independence of the regulation of the parameters of the drilling mode, the possibility of triggering large pressure drops on the bit, a significant increase in penetration per bit trip due to lower rotational frequencies, etc.
Turbine drilling
In turbine drilling, the bit is connected to the turbine shaft of the turbo drill, which is set in rotation by the movement of fluid under pressure through a system of rotors and stators. The load is generated by a fraction of the weight of the drill pipe.
The highest torque is due to the resistance of the rock to the rotation of the bit. The maximum torque determined by the calculation of the turbine (the value of its braking torque) does not depend on the depth of the well, the rotational speed of the bit, the axial load on it and the mechanical properties of the rocks being drilled. The coefficient of power transfer from the power source to the destructive tool in turbine drilling is higher than in rotary drilling.
However, during turbine drilling, it is impossible to independently regulate the parameters of the drilling mode, and at the same time, the energy consumption per 1 m of penetration, the costs of the amortization of turbodrills and the maintenance of workshops for their repair are high.
The turbine drilling method has become widespread in Russia thanks to the work of VNIIBT.
Drilling with screw (positive displacement) motors
The working bodies of the engines are created on the basis of a multi-thread screw mechanism, which makes it possible to obtain the required rotational speed with an increased torque compared to turbodrills.
Downhole motor consists of two sections - motor and spindle.
The working bodies of the motor section are the stator and the rotor, which are a screw mechanism. This section also includes a double-pivot joint. The stator is connected to the drill string by means of a sub. The torque is transmitted from the rotor to the output shaft of the spindle by means of a double-joint.
The spindle section is designed to transmit the axial load to the bottomhole, to absorb the hydraulic load acting on the motor rotor, and to seal the lower part of the shaft, which contributes to the creation of a pressure drop.
In screw motors, the torque depends on the pressure drop across the motor. As the shaft is loaded, the torque developed by the engine increases, and the pressure drop in the engine also increases. Performance characteristic a screw motor with the requirements of effective working of bits allows you to get a motor with an output shaft speed in the range of 80-120 rpm with increased torque. The specified feature of screw (positive displacement) motors makes them promising for implementation in drilling practice.
Drilling with an electric drill
When using electric drills, rotation of the bit is carried out by an electric (three-phase) AC motor. Energy is supplied to it from the surface through a cable located inside the drill pipe string. The drilling fluid circulates in the same way as in rotary drilling. The cable is inserted into the pipe string through a pantograph located above the swivel. The electric drill is attached to the lower end of the drill string, and the bit is attached to the shaft of the electric drill. Advantage electric motor before the hydraulic one is that the rotational speed, torque and other parameters of an electric drill do not depend on the amount of fluid supplied, its physical properties and the depth of the well, and on the possibility of controlling the engine operation from the surface. The disadvantages include the difficulty of supplying energy to the electric motor, especially at elevated pressure, and the need to seal the electric motor from the drilling fluid.
Promising directions in the development of drilling methods in world practice
In domestic and foreign practice, research and development are being carried out.
work in the field of creating new drilling methods, technologies, equipment.
These include deepening in rocks using explosions, destruction of rocks using ultrasound, erosion, using a laser, vibration, etc.
Some of these methods have been developed and are applied, albeit in an insignificant amount, often at the experimental stage.
Hydromechanical the method of destruction of rocks when deepening wells is increasingly used in experimental and field conditions... S.S. Shavlovsky carried out a classification of water jets that can be used when drilling wells. The basis of the classification is the developed pressure, the working length of the jets and the degree of their effect on rocks of various compositions, cementation and strength, depending on the diameter of the nozzle, the initial pressure of the jet and the flow rate of water. The use of water jets allows, in comparison with mechanical methods, to increase the technical and economic indicators of well drilling.
At the VII International Symposium (Canada, 1984), the results of work on the use of water jets in drilling were presented. Its capabilities are associated with continuous, pulsating or intermittent fluid supply, the presence or absence of abrasive material and technical and technological features of the method.
Erosive drilling provides deepening speeds 4-20 times higher than rotary drilling (under similar conditions). This is primarily due to the significant increase in power supplied to the bottom in comparison with other methods.
Its essence lies in the fact that an abrasive material - steel shot - is supplied to the bit of a special design together with the drilling fluid. The size of the granules is 0.42 - 0.48 mm, the concentration in the solution is 6%. Through the bit nozzles, this solution with shot is fed to the bottomhole at high speed and the bottomhole is destroyed. In the drill string, two filters are sequentially installed, designed to screen out and retain particles, the size of which does not allow them to pass through the bit nozzles.
One filter is above the bit and one is below the kelly where cleaning can be done. Chemical treatment of drilling mud with shot is more difficult than treatment of conventional mud, especially at elevated temperatures.
The peculiarity is that it is necessary to keep the shot in the solution in suspension and then generate this abrasive material.
After preliminary cleaning of the drilling fluid from gas and cuttings with the help of hydrocyclones, the shot is taken and kept in a wet state. Then the solution is passed through fine hydrocyclones and a degasser and its lost performance is restored by chemical treatment. Part of the drilling fluid is mixed with shot and fed into the borehole, on the way mixing with conventional drilling fluid (in a calculated ratio).
Lasers- quantum generators of the optical range - one of the remarkable achievements of science and technology. They have found wide application in many fields of science and technology.
According to foreign data, it is currently possible to organize the production of continuous gas lasers with an output power of 100 kW and above. The efficiency (efficiency) of gas lasers can reach 20 - 60%. The high power of lasers, provided that extremely high radiation densities are obtained, is sufficient to melt and vaporize any materials, including rocks. At the same time, the rock also cracks and flakes.
The minimum power density of laser radiation, sufficient for the destruction of rocks by melting, has been experimentally established: for sandstones, siltstones and clays, it is approximately 1.2-1.5 kW / cm 2. The power density of the effective destruction of oil-saturated rocks due to thermal processes of oil combustion, especially when blowing air or oxygen into the zone of destruction, is lower and amounts to 0.7 - 0.9 kW / cm 2.
It is estimated that for a well with a depth of 2000 m and a diameter of 20 cm, it is necessary to spend about 30 million kW of laser radiation energy. Well drilling of such depth is not yet competitive in comparison with traditional mechanical drilling methods. However, there are theoretical prerequisites for increasing the efficiency of lasers: with an efficiency equal to 60%, energy and cost costs will significantly decrease and its competitiveness will increase. When using a laser in the case of drilling wells with a depth of 100-200 m, the cost of work is relatively low. But in all cases, during laser drilling, the cross-sectional shape can be programmed, and the borehole wall will be formed from the rock melt and will be a glassy mass, which makes it possible to increase the coefficient of displacement of the drilling mud by cement. In some cases it is obviously possible to do without well casing.
Foreign companies offer several designs of lasers. They are based on a powerful laser housed in a sealed housing that can withstand high pressure. Temperature resistance has not yet been worked out. For these structures, laser radiation is transmitted to the bottomhole through a light-guiding fiber. As the rock is destroyed (melted), the laser drill is fed down; it can be equipped with a vibrator installed in the housing. When the shell is pressed into the molten rock, the wellbore walls can be compacted.
In Japan, the production of carbon dioxide gas lasers has begun, which, when used in drilling, will significantly (up to 10 times) increase the penetration rate.
The borehole section during the formation of the borehole by this method can have an arbitrary shape. The computer, according to the developed program, remotely sets the scanning mode of the laser beam, which makes it possible to program the size and shape of the wellbore.
Carrying out laser thermal works is possible in the future in perforating works. Laser perforation will provide controllability of the process of destruction of the casing string, cement stone and rock, and can also facilitate the penetration of channels to a considerable depth, which will undoubtedly increase the degree of perfection of the formation penetration. However, rock fusion, which is advisable when deepening the well, is unacceptable here, which should be taken into account when using this method in the future.
In domestic works there are proposals for the creation of laser plasma installations for thermal drilling of wells. However, the transportation of plasma to the bottom of the well is still difficult, although research is underway to explore the possibility of developing light guides ("light guide tubes").
One of the most interesting methods of influencing rocks, possessing the criterion of "universality", is the method of melting them by means of direct contact with a refractory tip - a penetrator. Significant advances in the creation of thermally stable materials made it possible to transfer the issue of rock melting to the area of real design. Already at a temperature of about 1200-1300 ° C, the melting method is workable
It is found in loose soils, sands and sandstones, basalts and other rocks of the crystalline basement. In the rocks of the sedimentary complex, the drilling of clay and carbonate rocks requires, apparently, a higher temperature.
The fusion drilling method makes it possible to obtain on the borehole walls a sufficiently thick sitall crust with smooth inner walls. The method has a high coefficient of energy input into the rock - up to 80-90%. In this case, the problem of removing the melt from the bottomhole can be solved, at least in principle. Coming out through the outlet channels or simply flowing around a smooth penetrator, the melt, solidifying, forms a sludge, the size and shape of which can be controlled. The cuttings are carried away by a fluid that circulates above the drill and cools the top of the drill.
The first projects and samples of thermal drills appeared in the 60s, and the theory and practice of rock melting began to develop most actively from the mid 70s. The efficiency of the melting process is mainly determined by the temperature of the surface of the penetrator and the physical properties of rocks and depends little on the mechanical and strength properties. This circumstance determines a certain universality of the melting method in the sense of its applicability for driving various rocks. The melting temperature range of these various polymineral multicomponent systems generally falls within the range of 1200-1500 ° C at atmospheric pressure. In contrast to the mechanical method of destruction of rocks by melting, with an increase in the depth and temperature of the underlying rocks, it increases its efficiency.
As already mentioned, in parallel with the penetration, casing and isolation of the borehole walls are carried out as a result of the creation of an impermeable vitreous annular layer. It is not yet clear whether the surface layer of the penetrator will wear out, what is its mechanism and intensity. It is possible that fusion drilling, although at a low speed, can be carried out continuously within the interval determined by the well design. This design itself, due to the continuous fastening of the walls, can be greatly simplified, even in difficult geological conditions.
It is possible to imagine the technological procedures associated only with the fastening and insulation of the walls in series with the drilling of the borehole using the conventional mechanical drilling method. These procedures can only apply to information
terval, which are dangerous due to the possibility of various complications.
From the point of view of technical implementation, a conductor should be provided to the injection elements of the penetrator similar to that used in electric drilling.
3. Classification of wells
Wells can be classified by function, wellbore and screen profile, filter perfection and design, number of casing strings, location on the surface of the earth, etc.
Wells are distinguished according to their purpose: reference, parametric, structural exploration, exploration, oil, gas, geothermal, artesian, injection, observation, special.
According to the profile of the wellbore and filter, the wells are: vertical, inclined, directionally oriented, horizontal.
According to the degree of perfection, wells are distinguished: superperfect, perfect, imperfect in the degree of opening of productive layers, imperfect in the nature of opening of productive layers.
According to the filter design, wells are classified into: loose, fixed with a production string, fixed with a plug-in slotted or mesh filter, fixed with a gravel-sand filter.
According to the number of columns in the well, wells are distinguished: single-column (only production casing), multi-column (two-, three-, n-column).
By their location on the surface of the earth, wells are distinguished: located on land, offshore, offshore.
The purpose of the structural exploration wells is to establish (clarify) tectonics, stratigraphy, lithology of the rock section, assess possible productive horizons.
Exploration wells are used to identify productive formations, as well as to delineate developed oil and gas fields.
Extractive (operational) are intended for the extraction of oil and gas from the earth's interior. This category also includes injection, appraisal, observation and piezometric wells.
Injection is required to inject water, gas or steam into the reservoir in order to maintain reservoir pressure or treat the bottomhole zone. These measures are aimed at lengthening the period of the flowing method of oil production or increasing the efficiency of production.
The purpose of appraisal wells is to determine the initial water-oil saturation and residual oil saturation of the formation and conduct other studies.
Control and observation wells are used to monitor the development target, study the nature of the movement of formation fluids and changes in gas-oil-s saturation of the formation.
Reference wells are drilled to study the geological structure of large regions in order to establish general patterns of bedding of rocks and to identify the possibilities of formation of oil and gas deposits in these rocks.
1. How are wells classified?
2. What methods of drilling wells are known?
3. What is laser drilling? ?
Literature
1. Bagramov R.A. Drilling machines and complexes: Textbook. for universities. - M .: Nedra, 1988. - 501 p.
2. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Well Completions: Textbook. manual for
universities. - M: LLC "Nedra-Business Center", 2000. - 670 p.
3. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Complications and accidents during oil drilling
and gas wells: Textbook. for universities. - M .: LLC "Nedra-Business Center", 2000. -679 p.
4. Basarygin Yu.M., Bulatov A.I., Proselkov Yu.M. Oil and gas drilling technology
wells: Textbook. for universities. - M .: LLC "Nedra-Business Center", 2001. - 679 p.
5. Boldenko DF, Boldenko FD, Gnoyevykh A.N. Downhole motors. - M.: Nedra,
