RU2642699C1 - Method for well drilling process conditions regulation - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method is based on bit delivery into a recess by a three-channel mechanical and hydraulic capacity converter, according to the proposed solution, mechanical energy is represented by a load on the "bit-face" system defined by the dead weight of the compressed part of the string, and is supplied to the system with a speed defined by the tool feed transition factor and the associated condition ensuring the optimisation of the drilling process, defined by a mathematical expression.

EFFECT: determination of the parameters of the conditions ensuring mechanical energy supply to the bit-face system, taking into account the rate of rock fracture on the face.

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Description

The invention relates to drilling wells and may find application in regulating drilling conditions.

A known method of regulating the conditions of the drilling process and the layout of the bottom of the drill string for its implementation (US Pat. RF №2550117, ЕВВ 44/00, publ. 05/10/2015. Bull. №13), in which the bit is a three-channel converter of mechanical and hydraulic capacities in deepening, and the channel of the number of revolutions of the bit and the channel of load on the bit jointly implement the first stage of the deepening process - the destruction of the rock face by the consumption of mechanical power, and the flow channel of the flushing fluid implements the second stage of the deepening - och the source of the face from the destroyed rock by the flow of hydraulic energy.

Means that implement the drilling process can be divided into two parts:

- the executive part - the system "bit-face", directly implementing the destruction of the rock face and its deepening;

- specifying the operating mode of the executive part, by supplying mechanical and hydraulic capacities to it.

Both types of energy are transported to the bit-bottom system using a drill pipe string, which is a very unstable system with distributed parameters. In this case, the speed of transportation or supply, in particular mechanical energy, is decisive in the formation of the mode of destruction of the face rock, i.e. in the implementation of the first stage of the drilling process.

The prototype examines the work of the Executive part of the system "bit-face", and from the point of view of power consumption. The supply of energy to the "bit-face" system, and even more so the supply dynamics, in particular mechanical, are not taken into account in the prototype, which is its drawback.

The objective of the invention is to determine the parameters of the conditions that provide the supply of mechanical energy to the "bit-face" system, taking into account the rate of rock destruction at the bottom, and the conditions in the form of transmission coefficients of the elements of the "bit - face - drill pipe string - hoisting mechanism".

The problem is achieved by the fact that according to the method of regulating the conditions of the drilling process based on the representation of the bit by a three-channel converter of mechanical and hydraulic capacities into a recess, according to the proposed solution, mechanical energy is represented as a load on the "bit-bottom" system, determined by the dead weight of the compressed part of the column and fed to the system at a speed determined by the transmission coefficient of the feed of the tool and the condition ensuing from the coefficient providing ju drilling process, defined by the expression:

while the conditions must be met: f ₁ (t) = f ₂ (t) = 0 - the condition for optimal drilling and бур _b = ϑ _p - the condition for optimal regulation of the drilling process,

where k _p - transmission coefficient of the feed tool;

ϑ _p - tool feed speed;

ϑ _b - mechanical drilling speed;

f ₁ (t) is the negative dynamic component of the load G (t) generated during drilling;

f ₂ (t) is the positive dynamic component of the load G (t) generated during drilling.

The load on the "chisel-face" system is carried out by the own weight of the compressed part of the drill pipe string. This is the only parameter in drilling that can be controlled in an operational manner. The parameter under the influence of which the drilling (deepening) process is carried out by continuously restoring the load value decreasing as the bit-bottom-hole system deepens. At the same time, the decrease in the dead weight of the compressed part is compensated for by the weight of the stretched part of the column moving after the compressed part. In other words, to ensure the continuity of the drilling process, the entire drill pipe string and tackle block must move at a recess speed (mechanical drilling speed), under the control of the winch brake system. The load on the chisel-face system can be carried out in two ways. The first method is a braked winch method or a pulsed one, which is carried out as follows [E.T. Strugovets, M.G. Lugumanov. On the search for optimal loads on the bit when drilling with downhole motors. NTV Logger. Vol. 5-6 (132-133, Tver, 2005]. The winch is braked and the system is loaded with a drill pipe string, the value of which G _max is determined by the driller by controlling the winch brake system and monitoring by the weight indicator. Under this load, the drilling process is carried out. as deepening, the load decreases to a certain value of G _min , the value of which is controlled by the driller according to the weight indicator, while the drilling time from changing the load from G _max to G _min is subjective, since the values of maximum and minimum load are subjective Obviously, during this time, the drilling process is implemented by all imaginable and inconceivable modes of its operation.The second method is a method of automatically maintaining a constant feed rate of the tool depending on the bottomhole conditions, which has not yet been implemented. Thus, to ensure the continuity of the drilling process it is necessary to carry out the process of supplying the tool: drill bits and drill pipe string to the bottom.

In FIG. 1-4 are diagrams and mechanical circuits explaining the formation of a dynamic component to the "chisel-face" system and feed at a feed rate of the drilling tool.

In FIG. 1 shows a detailed diagram of the serial interaction of the drilling tool, i.e. drill bits, drill pipe strings, as well as ground equipment that feed at the feed rate ϑ _{p the} load on the bit-bottom system.

In FIG. Figure 2 shows a diagram of the interaction of the elements of the "chisel-face - drill pipe string" with lumped parameters.

In FIG. Figure 3 shows the mechanical chain of interaction of the elements of the "chisel-face - drill pipe string" with lumped parameters.

Based on FIG. 2, 3, differential equations are compiled that determine the formation of the dynamic component of the load on the "bit-face" system acting as internal feedback.

In FIG. Figure 4 shows the mechanical chain of the “chisel-face” system with the dynamic component of the load on the system as internal feedback.

In the diagram, the positions indicate:

1. The well;

2. The system "chisel-face";

3. Downhole hydraulic motor;

4. Return - stock flow of flushing fluid;

5. The compressed part of the drill pipe string;

6. The source stream of flushing fluid;

7. The stretched part of the drill pipe string;

8. Rotary table;

9. Kelly (“square");

10. Hose;

11. The boring pump;

12. Swivel;

13. Fur block with crown block;

14. The receiving capacity of the washing fluid;

15. Gutter;

16. The set of sludge sieve fractions F1-F4;

17. Receiver sludge;

18. The capacity of the finished flushing fluid;

19. The engine of electric or internal combustion of the mud pump;

20. Power cable tension sensor;

21. Power cable;

22. Weight indicator;

23. Drill winch;

24. Hoist engine;

25. Brake system of a drawworks;

26. Measuring cable;

27. Drilling speed meter;

28. The rotor engine.

It should be noted that as a measuring instrument of mechanical drilling speed 27, the equipment used to move the towing block ARP-N, commercially available by NPK AMK Horizont LLC, is based on the rotation of the additional measuring drum connected by the measuring cable 26 to the traveling block 13.

In general, the armament of the bit, forming the updated bump-like surface of the face, moves with speed

- усредненная мгновенная механическая скорость углубления поверхности забоя;Where

- averaged instantaneous mechanical speed of the deepening of the surface of the face;

ϑ _i is the instantaneous penetration rate into the i-ro breed of the tooth;

N is the number of interacting (embedded) teeth.

The deepening of the face with the appropriate feed bit for a certain period of time can be determined by the expression

- углубление забоя;Where

- deepening of the face;

Δt - a certain period of time (solitude), for example, the time of one or more revolutions of the bit.

Following the deepening face, with appropriate cleaning from the destroyed rock, a bit is deepened, the value of which can be determined by the expression

where ϑ _d is the speed of the deepening of the body of the bit.

меньше углубления своего собственного вооружения

что обусловлено неровностями поверхности забоя, некачественной очисткой от разрушенной породы, неравномерностью осевой нагрузки, обусловленной трением и т.д. Перечисленное представляют собой помехи на забое, наличие которых позволяют рассматривать корпус долота и его вооружения условно автономно. Так как

при условии равенства времени Δt.Moreover, in the General case, the deepening of the body of the bit

less deepening their own weapons

due to roughness of the surface of the face, poor cleaning of the destroyed rock, uneven axial load due to friction, etc. The above are interference on the face, the presence of which allows us to consider the body of the bit and its weapons conditionally autonomously. As

subject to equal time Δt.

Based on the foregoing and expressions (2) and (3), we write down the transmission coefficient of the destroyed rocks by the “chisel-face” system in the form

For the implementation of continuous destruction of the rock by armament, chisels and deepening of the face are necessary: firstly, cleaning (washing) the face from the destroyed rock, which is carried out by washing liquid; secondly, to feed - linear movement (deepening) of the bit by external force - load; since the bit itself does not have such capabilities. The load on the bit can create only the own weight of the compressed part of the drill pipe string, which at the same time transports the flushing fluid to the bottom. The bit feed rate can be determined by the expression

where ϑ _p is the feed rate of the tool.

Then the transmission coefficient of the feed "bit-column" can be written as

where k _dk - the transmission coefficient of the feed rate of the system "bit-column".

The transmission coefficients "bit-bottom" k _dz and "bit-column" k _d-k are the transmission coefficients of the rock fracture transducer and the tool feed transducer and which are connected in series. Then you can write

Instantaneous mechanical speed is a rapidly changing quantity with a large dispersion, which does not allow using it to assess the quality of process control. To do this, use the averaged values of the mechanical speed [V.A. Brazhnikov, V.A. Kuznetsov. Information devices for determining the effectiveness of drilling process control. M .: Nedra, 1978]. Therefore, from (2) we have

Given expression (8), formula (7) takes the form

- коэффициент передачи, определяющий условия подачи инструмента, обеспечивая непрерывность процесса бурения, причем условие, формируемое непосредственно при взаимодействие вооружения долота с забоем скважины;Where

- transmission coefficient that determines the conditions for the supply of the tool, ensuring the continuity of the drilling process, and the condition is formed directly during the interaction of the armament of the bit with the bottom of the well;

ϑ _p - feed rate of the drilling tool;

ϑ _b - mechanical drilling speed.

The drill pipe string consists of two parts: compressed 5 and stretched 7. In addition, the tool is supplied by ground triggers: tackle block 13, drill winch 23, brake system of winch 25. Therefore, we consider the conditions for feeding the tool with this in mind. Directly the load on the "bit-face" system is carried out by the compressed part 5 of the drill pipe string. Then you can write

- коэффициент передачи скорости подачи сжатой частью колонны;

- transmission coefficient of the feed rate by the compressed part of the column;

ϑ _ps - feed rate of the compressed part.

Following the compressed part 5 of the column, the extended part 7 moves with a speed ϑ _pr , compensating for the decreasing weight of the compressed part 5. Then

- коэффициент передачи скорости подачи растянутой части 7. Тогда общий коэффициент подачи колонны бурильных труб

- the transmission coefficient of the feed rate of the stretched part 7. Then the total feed coefficient of the drill pipe string

where k _pc is the transmission coefficient of the feed rate of the drill pipe string.

The stretched part 7 of the drill pipe string is suspended on the hook of the tackle block 13, creating a load on it, with a part of the drill pipe string not participating in the creation of a load on the "chisel-bottom" system. Therefore, as the column moves, the tackle block 13 should descend. Then

- коэффициент передачи скорости подачи талевого блока 13;Where

- transmission coefficient of the feed rate of the traveling block 13;

ϑ _tal - feed rate of the tackle block 13.

The tackle block 13 descends due to the unwinding of the cable from the winch drum 23. Then

- коэффициент передачи скорости подачи буровой лебедки;Where

- transmission coefficient of the winch feed rate;

ϑ _forehead = πDn _l - peripheral speed of the winch drum;

D is the diameter of the winch drum;

n _l - the number of revolutions of the winch drum 13 per unit time. Then the gear ratio of the feed rate by the surface trigger

The overall transmission coefficient of the feed rate of the drill pipe string and the surface tripping mechanism

It can be seen from the analysis that both sections of the drill pipe string, compressed 5 and extended 7, and elements of the surface tripping mechanism are equivalent in the formation of the transmission coefficient of the bit - bottomhole - column - ground equipment system, due to their sequential action. Therefore, in the general case, we can write

where k _p - transmission coefficient of the feed tool;

ϑ _p - tool feed speed;

ϑ _b - mechanical drilling speed.

Obviously, condition (12), which ensures the optimization of the drilling process, must be equal to unity, i.e.

It is clear from the previous one that condition (13) can be violated by any of the elements of the system under consideration that are external to the “chisel-face” system, since each of them has its own elastic mechanical properties. To determine the permissible deviations of the parameters of the considered elements from the required, a separate analysis is required. At the same time, in the "bit-face" system itself, when the face rock is destroyed and it is cleaned of the destroyed rock, an internal relationship is made between the drilling speed ϑ _b and the feed rate of the tool ϑ _p . In the general case, the transmission coefficient of the tool feed can be more or less than unity, i.e.

or, as a consequence of expression (14)

Therefore, we analyze the consequences of inequality

k ≠ 1, or θ _n -θ _b = 0.

For this, we consider a mechanical system that carries out the drilling process, which is shown in FIG. 1, and its mechanical chain, in FIG. 2.

In FIG. 2:

ϑ (t) is the source of speed of the system "bit-face";

M is the mass of the layout of the bottom of the drill pipe string and the lower, compressed part of the string;

B is the equivalent resistance (friction) to the motion of the mass M;

K is the stiffness of the spring, which determines the elastic properties of the interface between the mass M and the "chisel-bottom" system and the compressed part of the drill pipe string;

X ₁ - movement (supply) of a body of mass M;

X ₂ - movement (deepening) of the speed source, while the deepening can be determined by the expression

where h is the height of the tooth armament bits;

z is the number of teeth of the outer crown of the cone;

i = D / d is the gear ratio of the bit;

D and d - respectively, the diameter of the bit is the parameter of the cone;

G (t) is the load on the system, determined by the force of the weight of the compressed part of the drill pipe string;

n is the number of revolutions of the bit.

We consider two cases.

A case is possible during the transition of a process from hard to soft rocks or when bits meet with cracks, voids, etc.

- скорость бурения, а

- скорость подачи инструмента, то можно записать ϑ_б>ϑ_п. В этом случае ведущую роль процесса бурения играет система «долото-забой», непосредственно осуществляющая бурение, а ведомую роль играет колонна бурильных труб, обеспечивающая систему нагрузкой. Обращаясь теперь к схемам фиг. 2 и фиг. 3 и применяя второй закон Ньютона, запишем уравнение движения в виде [М.Ф. Гарднер, Дж. Л. Бернс. Переходные процессы в линейных системах с сосредоченными постоянными. Физматиз, 1961]Case A, when x ₂ > x ₁ . Insofar as

- drilling speed, and

- the feed rate of the tool, then you can write ϑ _b > ϑ _p . In this case, the leading role of the drilling process is played by the “chisel-face” system, which directly carries out drilling, and the guided role is played by the drill pipe string, which provides the system with a load. Turning now to the diagrams of FIG. 2 and FIG. 3 and applying Newton’s second law, we write the equation of motion in the form [M.F. Gardner, J.L. Burns. Transients in linear systems with concentrated constants. Fizmatiz, 1961]

- сила, определяющая относительное перемещение концов пружины, обладающей жесткостью К;Where

- the force that determines the relative movement of the ends of the spring, with rigidity K;

- сила, определяющая создание разности скоростей концов элемента сопротивления трения В.

- the force that determines the creation of the difference in speed of the ends of the element of friction resistance B.

We substitute in equation (16) the expression for the elastic force of the spring and for the friction force we obtain:

Equation (17) can be written as

- известные функции, тоSince x ₂ (t) and

are known functions then

- определяет известную динамическую внешнюю силу - отрицательную динамическую составляющую нагрузки G(t), порождаемую в процессе бурения.

- determines the known dynamic external force - the negative dynamic component of the load G (t) generated during the drilling process.

Case B, when x ₂ <x ₁ or the feed rate of the tool ϑ _{n is} greater than the drilling speed, ϑ _b ϑ _n > ϑ _b . In this case, the initiative of the drilling process belongs to the drill pipe string, providing the “bit-bottom” system with the load G (t) and forcing the system to work in forced mode. Similar to the previous equation of motion

Equation (19) can be written as

- положительная динамическая составляющая нагрузка G(t), порождаемая в процессе бурения.Where

- positive dynamic component load G (t) generated during drilling.

From the expressions (8) and (20) it can be seen that the dynamic component behaves ambiguously:

- when ϑ _b > ϑ _{n, the} dynamic component f ₁ (t) tends to reduce the load on the system G (t) and thereby reduce the drilling speed ϑ _b ;

- when ϑ _b <ϑ _{p, the} dynamic component f ₂ (t) tends to increase the load on the system G (t) and thereby increase the drilling speed ϑ _b .

From the foregoing it follows that the dynamic component of the load f ₁ (t) and f ₂ (t) tends to stabilize the mechanical drilling speed, i.e. drilling process. A stabilizing property of processes is usually feedback. Therefore, the dynamic component is internal feedback and it is generated by the system “chisel-bottom-drill pipe string” under the condition ϑ _b ϑ ϑ _p .

Then the circuit of FIG. 3 we present in the form of FIG. 4, which shows how the dynamic component f (t) generated by the bit-bottom-hole system is added (subtracted) to the bit-to-face system under load G (t) created by the dead weight of the compressed part of the drill pipe string. drill pipe string "in the process of drilling a well, subject to inequality in the feed rates of the tool and the drilling of the well, i.e. ϑ _p ≠ ϑ _b , while the dynamic component is the internal feedback of the system, contributing to an increase in the stability of the “chisel-face” system and especially in transient conditions, the magnitude of this feedback (dynamic component) is determined not only by the drilling speed (different from the feed rate ), but also by the elastic properties of the “chisel – bottomhole – drill pipe string” system and its friction against the borehole walls.

Under the condition ϑ _b = ϑ _n, expressions (3) and (6) take the form

Moreover, f ₁ (t) = f ₂ (t) = 0. This condition is the condition for optimal drilling, and the condition ϑ _b = ϑ _p is the condition for optimal regulation of the drilling process.

Claims (8)

A method for regulating the conditions of a drilling process based on the representation of a bit by a three-channel converter of mechanical and hydraulic capacities into a depression, characterized in that mechanical energy is represented as a load on the "bit-bottom" system, determined by its own weight of the compressed part of the column, and fed to the system with the speed determined by the transmission coefficient of the tool feed and the conditions arising from the coefficient providing the optimization of the drilling process, defined by the expression:

while the conditions must be met: f ₁ (t) = f ₂ (t) = 0 - the condition for optimal drilling and бур _b = ϑ _p - the condition for optimal regulation of the drilling process, where k _p - transmission coefficient of the feed tool; ϑ _p - tool feed speed; ϑ _b - mechanical drilling speed; f ₁ (t) is the negative dynamic component of the load G (t) generated during drilling; f ₂ (t) is the positive dynamic component of the load G (t) generated during drilling.

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