RU2009306C1 - Cone bit - Google Patents

Abstract

FIELD: cone bits for well drilling. SUBSTANCE: relation of length of working surface in cone bit of auxiliary periphery cutting structure to bit diameter is determined as l/D≥ 0,127, with 1/D varying from 0.127-0.5, where 1 is length of working surface of periphery cutting structure, and D is bit diameter. Relation of width of step formed by leading and periphery cutting structure to bit diameter is determined by a/D≥ 0,127+0,9[b], where a is width of step, and b is step height. EFFECT: higher efficiency. 2 cl, 6 dwg

Description

 The invention relates to a rock cutting tool for drilling wells, and in particular to cone drill bits.

 A drill bit is known, including cutters, the axes of which, to ensure the sliding of weapons along the face in order to increase mechanical speed, are offset relative to the axis of the bit, that is, they do not intersect with this axis [1].

 Due to the fact that the peripheral armament of this bit due to the displacement of the axes performs an increased work on the milling of the wall in relation to the bits without displacement of the axes, this armament is subject to increased wear, especially when passing abrasive rocks.

 These shortcomings were eliminated in bits with stepped peripheral weapons without shifting the cone axes, where the slipping of weapons performing the function of advancing the face is ensured by finding these weapons at different geometric levels, which is achieved by stepped execution of peripheral weapons [2]. In this case, either the main advanced weapon slides when the instantaneous axis of rotation passes through its working surface, or the peripheral subsequent one in the similar position of the instantaneous axis of rotation.

 The well-known cone bit adopted for the prototype includes cones with step peripheral weapons with the following ratio of step and bit sizes: a / D = 0.111 with a / b = 0.019 with working surface length l / D = 0.088; 0.065; 0.003, where a is the width of the step formed by the working surfaces of the leading primary and subsequent peripheral weapons; b is the height of the step; l is the length of the working surface of peripheral weapons; D is the diameter of the bit.

 At the beginning of the work of the known bit due to the fact that the step is partially chipped and its width does not provide reliable engagement with the rock being destroyed and does not provide slippage of the main advanced weapons, enhanced slip and, accordingly, peripheral weapons are subject to wear. After reaching a certain level of wear of peripheral weapons, it enters into reliable engagement with the face, providing gliding of the main weapons [3]. Worn-out peripheral weapons experience a significant reaction of the borehole wall, destroying the lock bearings of the bit supports, leading to its premature failure or cessation of drilling due to increased torque.

 The aim of the invention is to increase the operating time of the bit by reducing the wear of peripheral weapons by eliminating its slippage along the bottom of the well.

This goal is achieved by the fact that in the well-known cone bit, including cone with step peripheral weapons, the ratio of the length of the working surface of the subsequent peripheral weapons and the diameter of the bit is defined as
l / D ≥ 0.127, moreover, l / D can vary from 0.127 to 0.5, i.e., until the step degenerates in general, where l is the length of the working surface of peripheral weapons D is the diameter of the bit; the ratio of the width of the step formed by the leading main and subsequent peripheral weapons and the diameter of the bit is defined as
a / D ≥ 0.127 + 0.9 b,
where a is the width of the step;
b is the height of the step, D is the diameter of the bit.

 A comparable analysis with the prototype shows that the claimed bit is different in that the introduction of the design of the indicated ratios of the lengths of the working surface of the armament of the peripheral crowns, the width of the steps formed by the armaments of the leading main and subsequent peripheral armaments, allows for reliable engagement of the peripheral armament and face without slipping, which ensures achieving the objective of the invention.

 A comparison of the claimed technical solutions with the prototype made it possible to establish compliance with their criterion of "novelty." In the study of other well-known technical solutions in this technical field, signs that distinguish the claimed invention from the prototype were not identified, therefore, they provide the claimed technical solution with the criterion of "significant differences".

 In FIG. 1 shows a diagram of the overlap of the face with a serial bit; in FIG. 2 - armament of a known bit in contact with the formed face; in FIG. 3 - armament of the proposed bit in contact with the formed face; in FIG. 4 is a diagram of overlapping the face of the proposed bit; in FIG. 5 is a diagram for calculating the length of the working surface of a stepped peripheral weapon; in FIG. 6 - step sizes on the periphery of the face in experiments on its static destruction.

 The peripheral armament (Fig. 5), located at a different level relative to the main one, in the case of non-slip engagement, when the instantaneous axis of rotation passes through its working surface, provides a torque determined by the friction force of the armament and the shoulder equal to the radius of the crown.

M _N = F _N R _N.

Gliding of the main armament is provided at
M _N ≥M ₁ + M ₂ +. . . + M _N-1 .

Based on the equality of the blunting of weapons along the crowns and the uniformity of the breed, which ensures the equality of friction conditions on the crowns, the ratio will be fair
R _N l _N ≥R ₁ l ₁ + R ₂ l ₂ +. . . + R _{N - 1} l _N-1 .

x_пl_п
Таким образом, длина рабочей поверхности периферийного вооружения определяется

Для всех шарошек решение упрощается, поскольку длина рабочих поверхностей венцов основного вооружения определяется местом перехода на периферийную ступеньку (фиг. 3) с учетом коэффициента перекрытия и будет справедливо неравенство
Х_оl_oK ≅X_пl_п, где Х_о - координата основного вооружения;
Х_п - координата периферийного вооружения;
l_o - длина рабочих поверхностей основного вооружения до ступеньки;
l_п - длина рабочей поверхности периферийного вооружения;
К - коэффициент перекрытия.Neglecting the deviation of the face profile from the plane due to the small angle of deviation, taking into account geometric similarity, in a first approximation, the relation
X _N l _N ≥ X ₁ l ₁ + X ₂ l ₂ +. . . + X _N-1 l _N-1 , i.e., X _N l

x _p l _p
Thus, the length of the working surface of peripheral weapons is determined

For all cones, the solution is simplified, since the length of the working surfaces of the main weapon crowns is determined by the transition point to the peripheral step (Fig. 3) taking into account the overlap coefficient and the inequality
X _o l _o K ≅ X _p l _p where X _o - coordinate of the main weapons;
X _p - the coordinate of peripheral weapons;
l _o - the length of the working surfaces of the main weapons to the steps;
l _p - the length of the working surface of peripheral weapons;
K is the coefficient of overlap.

 Based on the coordinates of the working surfaces in FIG. 1, K = 0.8.

-

;
l_о=

-l_п ;
X_о=

;

-l

-l

K=

-

l_п
Раскрывая и упрощая, получаем квадратное уравнение
(К + 1) l_п ² - (К + 1) Dl_п + К

= 0 со следующим решением: l

=

=

1

где l_п1 = 0,873 D; l_п2 = 0,127 D, однако l_п изменяется от 0 до 0,5 D, тогда конкретное решение определяет l_п = 0,127 D. Таким образом длина рабочей поверхности ступенчатого периферийного вооружения в отношении к диаметру должна быть l/D ≥0,127, причем l/D может изменяться от 0,127, до 0,5, т. е. до вырождения ступеньки вообще.To solve the equation;
X _n =

-

;
l _o =

-l _p ;
X _o =

;

-l

-l

K =

-

l _p
Opening and simplifying, we obtain the quadratic equation
(K + 1) l _p ² - (K + 1) Dl _p + K

= 0 with the following solution: l

=

=

1

l where _n1 = 0,873 D; l _p2 = 0.127 D, however l _p varies from 0 to 0.5 D, then the specific solution determines l _p = 0.127 D. Thus, the length of the working surface of step-mounted peripheral weapons in relation to the diameter should be l / D ≥0.127, and l / D can vary from 0.127 to 0.5, i.e., until the step degenerates in general.

 The specified length l ensures the achievement of the objective of the invention, provided that the step is preserved at the bottom of the well, which is formed by stepwise armament of the bit. However, based on the data of (4), the step on the face is prone to partial destruction. Consequently, the dimensions of the bit armament step should ensure the peripheral weapon engagement with the rock at a length l ≥ 0.127 D, taking into account the cleavage of the step edge at the bottom of the well. The size of the cleavage can be determined from the analysis of the results of the study (4) by the static destruction of the step near the wall of the well with a single tooth on models of full-size face on analogs of rocks of different hardness. Based on the research results, the dependencies shown in FIG. 6. Line A on top, line B on the right and line C on the left limit the dimensions of the completely destructible step. The ratio c / b = 0.33 + 0.90 is the limitation of the destruction of the step with minimal energy consumption, where c is the width of the step on the rock block, b is the height of the step.

 Thus, the width of the step within these boundaries cannot be taken into account in ensuring high-quality engagement (without slipping) of the peripheral crowns. Therefore, after choosing the length of the working surface of peripheral weapons when determining the width of the step, these ratios are taken into account by adding C = 0.90 b.

Thus, the ratio of the width of the step formed by the leading main and subsequent peripheral weapons, and the diameter of the bit is defined as
a / D ≥ 0.127 + 0.90 b, where b is the height of the step formed by the leading and subsequent peripheral armament of the bit. The height of step b is equal to the height of the step on the blocks of rock studies (4).

 The proposed bits have an increase in penetration per bit up to 50% due to an increase in the bit operating time when the average technical drilling speed is exceeded. (56) 1. Paliy P.A., Korneev K.E. Drill bits. - M.: Nedra, 1971, 446 p.

 2. Peregudov A. A. et al. Results of industrial tests and experience with the use of AB bits in high-speed drilling. Mining enterprises. - M.: Tr. -yes. VNIIBT, no. 35, 1976, p. 115-118.

 3. Sinev S. V. On serial rolling cutter bits for machines 2 SBSh-200. NTS Mining Journal. Nedra, 1982, no. 2, p. 35-36.

 4. Research and development of effective processes of rock destruction during well drilling. - M.: Leninsky pr. 6, VNIIBT, report on the topic N 11 for 1976.

Claims (2)

 1. TORCH CHISEL containing cone with stepped peripheral weapons, characterized in that, in order to increase the working time of the bit by reducing the wear of the peripheral weapons by eliminating its slipping along the bottom of the well, the ratio of the length of the working surface of the subsequent peripheral structure and the diameter of the bit is defined as l / D ≥ 0.127, and l / D can vary from 0.127 to 0.5, where l is the length of the working surface of peripheral weapons, D is the diameter of the bit.  2. The bit according to claim 1, characterized in that the ratio of the width of the step formed by the leading main and subsequent peripheral weapons and the diameter of the bit is defined as a / D ≥ 0.127 - 0.9 b, where a is the width of the step; b is the height of the step.

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