RU2232249C1 - Vibration damper-reamer - Google Patents

Abstract

FIELD: well drilling technology.

SUBSTANCE: device has body with cylindrical longitudinal grooves on outer surface, calibrating bushing with match grooves on inner surface and resilient elements in form of rollers or balls. Forming diameters of cylindrical longitudinal grooves exceed outer diameters of resilient elements placed in cylindrical longitudinal grooves with capability for providing for device operation in mode of overrunning clutch in one or two movement directions: clockwise and counter-clockwise. In body of calibrating bushing, between grooves, longitudinal through slits are made, which form slitting spring mechanism with capability for resilient variation of outer diameter of calibrating bushing by means of autonomous jamming of resilient elements in cylindrical longitudinal grooves, in moments of interaction of these with greater diameter of longitudinal cylindrical grooves during device operation in mode of torsional vibrations of drilling column.

EFFECT: higher effectiveness of damping of torsional and transverse vibrations of lower portion of drilling column, higher durability of device during drilling of pilot wells, including those made by coltubing due to changes in construction.

2 cl, 6 dwg

Description

The invention relates to techniques for drilling oil and gas wells, in particular to devices for the disoriented control of their trajectory when damping vibrations of the layout of the bottom of the drill string (BHA) and calibrating the wall of the well.

Known vibration damper-calibrator (AS No. 832033, MKI E 21 17/26, BI No. 19, 1981), comprising a housing with grooves on the outer surface, a calibrating sleeve with grooves on the inner surface and an elastic element interacting with the grooves as body and bushings.

The reasons that impede the achievement of the technical result indicated below when using the known design of the vibration damper-calibrator include the fact that the known design has a short-lived elastic element due to its working conditions, relaxation properties and, as a consequence, the unevenness of its wear due to alignment problems, the result is poor quality of wellbore calibration, especially when drilling with coiled tubing.

Also known is a calibrator (AS No. 956735, MKI E 21 B 10/26, BI No. 33, 1982) comprising a housing, a removable sleeve with calibrating ribs and damping elements made of an elastic material and installed between the housing and the sleeve.

The reasons that impede the achievement of the technical result indicated below when using the known calibrator design include the inability to compensate for the natural radial wear of the working elements of the device during operation, which increases the drilling effort.

The closest device of the same purpose to the claimed invention in terms of features is a vibration damper-calibrator (AS No. 1006698 MKI E 21 10/26, BI No. 11, 1983), comprising a housing with cylindrical longitudinal grooves on the outer surface, a calibrating sleeve with corresponding grooves on the inner surface and roller elastic elements placed in these grooves - adopted as a prototype.

The reasons that impede the achievement of the technical result indicated below when using a well-known calibrator adopted for the prototype include the fact that the device does not compensate for the wear of the basic work elements and, as a result, the alignment of the drill string and the borehole is lost, especially when combined with random vibrational processes, occurring at the bottom and in the BHA.

The invention consists in the following.

The proposed invention solves a technical problem aimed at increasing the efficiency of damping torsional and lateral vibrations of BHA, increasing the durability of the device when drilling pilot wells, including coiled tubing, by changing the design.

The technical result in the implementation of the claimed invention is the expansion of the technological capabilities of the vibration damper-calibrator for the unoriented control of the trajectory during the drilling of especially pilot wells with the combined impact on the BHA of oscillations that are stochastic, nonlinear, random in nature and by increasing the durability of the basic structural elements by autonomous compensation of wear of calibrating surfaces.

The specified technical result in the implementation of this invention is achieved by the fact that in the known vibration damper calibrator, comprising a housing with cylindrical longitudinal grooves on the outer surface, a calibrating sleeve with mating grooves on the inner surface and elastic elements according to the invention forming the diameters of the cylindrical longitudinal grooves exceed the outer diameters of the elastic elements placed in cylindrical longitudinal grooves with the ability to ensure the operation of the device in overrunning clutch mode in one one or two directions of movement (clockwise and vice versa), while in the body of the calibrating sleeve, between the grooves, longitudinal through slots are made, forming a slotted collet-spring mechanism, which provides the possibility of elastic variation of the outer diameter of the calibrating sleeve by implementing self-locking of elastic elements in cylindrical longitudinal grooves at the moments of interaction with a large diameter of cylindrical longitudinal grooves with the possible operation of the device in the mode of torsional vibration of the drill column.

The beginning of the longitudinal through slots alternates alternately from the upper end of the calibrating sleeve, then from its lower end, and the bending stiffness of the slotted collet-spring mechanism, determined by the length of the slots and their pitch, is selected from a number of random numbers.

The elastic elements are made in the form of rollers or balls, the number of which in the grooves is stochastically determined by a number limited by the natural frequencies of the main harmonics of the transverse vibrations of the drill string in resonance modes, moreover, freely or spring-loaded.

In the study of the distinguishing features of the proposed vibration damper-calibrator, no analogues were identified that are characterized by signs that are identical to all the essential features of the claimed invention, which ultimately leads to the above technical result and confirms the materiality of the features of the claims.

The present invention is new, since no analogues with a combination of essential features identical to the proposed invention, providing the above technical result, which meets the criterion of "novelty", have been found.

The claimed vibration damper-calibrator does not follow explicitly from the prior art for a specialist, since the combination of essential features of the claimed invention only in the proposed combination ensures the achievement of the above technical result, which meets the criterion of "inventive step".

Figure 1 shows a vibration damper-calibrator, a partial section; figure 2 is a section aa in figure 1; figure 3 shows a partial section of the same section aa as an embodiment of a vibration damper-calibrator with longitudinal grooves on the inner surface of the calibrating sleeve, made with the maximum possible radii tending to the radius of the inner surface of the calibrating sleeve.

The vibration damper-calibrator contains a housing 1, a calibrating sleeve 2 with carbide weld 3, elastic elements 4, a nut 5, elastic rings 6 and 7 and a lock nut 8. The housing 1 has longitudinal grooves 9 on the outer surface, and the calibration sleeve has mating slots 10 on the inner surface. The elastic elements 4 are made in the form of rollers or balls (see figure 4).

Figures 4, 5, 6 show the manufacturing options of a vibration damper-calibrator with elastic elements made in the form of balls coated with an elastomer, which can be placed both freely (Figs. 4, 6) and spring-loaded: spring or elastomer 11 (Fig. 5).

Through the body of the calibrating sleeve 2, through longitudinal slots 12 are made of length l with a pitch of 2t from one end and after an interval of t from the other end with the same pitch of 2t in the form of a slotted spring (it is possible to manufacture with slots from only one end of the sleeve).

The device operates as follows.

In the working position, the vibration damper-calibrator is installed in the BHA above the bit or vice versa: the bottomhole reaction is transmitted from 2 to 1. Radial loads from the body 1 to the borehole wall are transmitted through the elastic element 4 and the calibrating sleeve 2 with surfacing 3. In the event of torsional vibrations, bearing, as a rule, an autonomous stochastic character, the vibration damper-calibrator operates in the overrunning clutch mode, which allows damping the resulting vibrations. At the same time, the borehole wall is calibrated and the lateral vibrations are damped due to the autonomous increase in the diameter of the sleeve 2 of the device at the time of elastic elements running onto the forming longitudinal grooves and wedging gaps. The frictional moment from the calibrating sleeve 2 to the housing 1 is transmitted through the elastic elements 4. The load in both cases is perceived simultaneously by several elastic elements. The length l and the pitch 2t of the slots 12 are randomly selected: for example, from a series of random numbers. The natural frequency of the BHA can be defined as:

where k _i is the dynamic stiffness of the perturbed section of the BHA participating in torsional i = 1 or transverse i = 2 vibrations of the drill string as an infinitely long shaft; m _i is the mass of a dynamically disturbed section during transverse vibrations:

where a ₂ is the shear wave velocity in the drill string,

σ is the Poisson's ratio;

E - Young's modulus of elasticity of the first kind,

ρ is the density of the BHA material,

- момент времени максимального динамического возмущения,

is the time instant of the maximum dynamic disturbance,

- период колебаний;

при крутильных колебаниях:G is the modulus of elasticity of the 11th kind,

- period of fluctuations;

during torsional vibrations:

a ₁ - the speed of propagation of torsion waves in the BHA,

Where

ω = ω _j · K _W · K _in - the frequency of the disturbing force,

where K _W - the number of cone bits,

K _in - empirical coefficient of slaughter,

ω _j is the angular frequency of the tooth 1 or soil 2 oscillations of the bit (j = 1, 2).

- длина динамически возмущенного участка обозначим Z_i. При совпадении ω₀ с ω возможны различные формы резонансов: параметрический, продольный, поперечный, крутильный и т.д., интерференция которых носит случайный, стохастический характер, который может быть определен корреляционной теорией или теорией случайных марковских процессов: характеризуется спектральной плотностью колебательных процессов, разложенной по превалирующим частотам (спектральная плотность характеризует распределение энергии процесса по его компонентам с различными частотами).Magnitude

- the length of the dynamically disturbed section is denoted by Z _i . If ω ₀ coincides with ω, various forms of resonances are possible: parametric, longitudinal, transverse, torsional, etc., the interference of which is random, stochastic in nature, which can be determined by the correlation theory or the theory of random Markov processes: it is characterized by the spectral density of the vibrational processes, decomposed in the prevailing frequencies (spectral density characterizes the distribution of the energy of the process over its components with different frequencies).

If there is sufficient information about the influence of factors on the performance of the layout, then the pattern of distribution of spectral density over the prevailing frequencies in the form of random numbers is established in a known manner. This can be a normal law, a Weibull distribution law, etc., with insufficient information, which is typical for pilot or exploratory wells, it is advisable to use a number of uniformly distributed, random numbers. Then from the table (Table of mathematical statistics. Bolshev L.N., Smirnov N.V. - Nauka, 1983, p.336, table 7.1a) we take a series of uniformly distributed random numbers 9, 10, 25, 33, 73, 91 - to calculate the lengths of the slits l _i performed on the calibrating sleeve.

For example, with a turbine method of drilling (t / b 3TSSh 1-195) with cone bits: the length of a dynamically disturbed section is Z _i = 60 ... 90 m, depending on the operating mode of the BHA.

The sum of the reciprocal of the considered random numbers is ≈0.3. The conversion factor is determined by:

Slot Length:

The slot length also determines the overall length of the calibrating sleeve, for example, based on the strength ≈600 ... 700 mm for a bit with a diameter of 215.9 mm.

The bending stiffness of the calibrating sleeve 2, selected taking into account the stochastic features of the oscillatory processes, in combination with the elasticity of the elements 4 provides increased flexibility of the BHA during the passage of highly curved sections of the well and, therefore, its increased reliability.

The pitch of the slits, the slot width and the number of elastic elements made in the form of rubberized balls and placed in the grooves of the housing and the calibrating sleeve freely or spring-loaded, are selected stochastically in the same way from a number of random numbers, taking into account the size of the calibrator and manufacturing technology.

The claimed invention is intended for use in drilling oil and gas wells to damp vibrations of the bottom of the drill string and calibrate the wall of the well. A technical design with a size range for various bit diameters has been developed for this design.

The advantage of the invention compared to the prototype is that it allows damping of transverse and torsional vibrations, calibrating the walls of the well by expanding the technological capabilities of the calibrator with disoriented control of the path of the well during drilling, taking into account random processes occurring at the bottom and BHA, with the possibility when coiled tubing drilling highly curved sidetracks.

Therefore, the claimed invention meets the criterion of "industrial applicability".

Claims (2)

1. Vibration damper-calibrator, consisting of a housing with cylindrical longitudinal grooves on its outer surface, a calibrating sleeve with mating grooves on its inner surface and elastic elements, included in the drill string, characterized in that the forming diameters of the cylindrical longitudinal grooves exceed the outer diameters of the elastic elements placed in cylindrical longitudinal grooves with the possibility of ensuring the operation of the device in the overrunning clutch mode in one or two directions of movement - clockwise and vice versa, in this case, longitudinal through slots are made between the grooves in the body of the calibrating sleeve, forming a slotted collet-spring mechanism with the possibility of elastic variation of the outer diameter of the calibrating sleeve by implementing self-locking of elastic elements in cylindrical longitudinal grooves at the moments of their interaction with a large diameter of longitudinal cylindrical grooves during possible operation of the device in the mode of torsional vibrations of the drill string. 2. The vibration damper-calibrator according to claim 1, characterized in that the beginning of the longitudinal through slots is alternately alternated either from the upper end of the calibrating sleeve, then from its lower end or in the middle of the sleeve, and the slotted collet-spring mechanism has a bending stiffness determined by the dimensions slots and their step between them, which is selected from a series of random numbers, while the elastic elements are made in the form of rollers or balls and placed in grooves stochastically, freely or spring-loaded, quantitatively limited by their own often the main harmonics of the transverse vibrations of the drill string.

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