Modular cutting-teeth drill bit with controllable drilling specific pressure

Abstract

A modular cutting-teeth bit having controllable specific pressure for drilling includes: a module (1), a modular unit (2), a bit body (3), conventional cutting teeth (4) and a nozzle (5). According to mechanical performance of the rocks in the strata drilled and requirements of drilling well, a combination of shapes, sizes and numbers of the module and the modular unit is optimized; effective abrasion edge length of the cutting unit on a certain portion of the bit is controlled; and a constant specific pressure of the cutting unit of the bit during the drilling process is maintained.

Claims

1. A modular cutting-teeth bit having controllable specific pressure for drilling, comprising: a module and a modular unit, wherein modular cutting teeth of said modular cutting-teeth bit having controllable specific pressure for drilling comprise said module for serving as matrix and said modular unit, a number of said module provided on said modular cutting-teeth bit is not less than 1, and a number of said modular unit provided on said module is not less than 2; wherein types thereof are selected from the group consisting of a PDC bit, a diamond bit, an impregnated bit, a roller bit, a cone-cutting bit and a compact bit comprising at least two number selected from the group consisting of said PDC bit, said impregnated bit, said roller bit and said cone-cutting bit, wherein a material of a bit body thereof is selected from the group consisting of a sintered body of tungsten carbide and alloy, steel, cemented carbide and metal matrix composite; a number of the modular unit is 2, cross-section shapes of the module and the module unit are circles, a diameter of the module is d, two kinds of modular units are provided, a total number of two modular units are provided, which are respectively a first modular unit and a second modular unit, diameters of the first modular unit and the second modular unit are respectively d.sub.1, and d.sub.2, a center distance along a Y axis direction of the first modular unit to the second modular unit is h.sub.1, wherein $0h_1\frac{d_1+d_2}{2}.$

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a sketch view of a modular cutting-teeth drill bit with controllable drilling specific pressure (PDC Bits) according to a preferred embodiment of the present invention.

(2) FIG. 2 is a structural sketch view of a modular cutting element according to a preferred embodiment of the present invention.

(3) FIG. 3 is a structural sketch view of a first combination manner of the modular cutting element according to an embodiment 1 of the present invention.

(4) FIG. 4 is a contrast diagram of the modular cutting element of the embodiment 1 of the present invention to distribution rule of a cutting-edge length of conventional PDC teeth.

(5) FIG. 5 is a structural sketch view of a second combination manner of the modular cutting element according to an embodiment 2 of the present invention.

(6) FIG. 6 is a contrast diagram of the modular cutting element of the embodiment 2 of the present invention to the distribution rule of the cutting-edge length of the conventional PDC teeth.

(7) FIG. 7 is a structural sketch view of a third combination manner of the modular cutting element according to an embodiment 3 of the present invention.

(8) FIG. 8 is a structural sketch view of a fourth combination manner of the modular cutting element according to an embodiment 4 of the present invention.

(9) FIG. 9 is a structural sketch view of a fifth combination manner of the modular cutting element according to an embodiment 5 of the present invention.

(10) FIG. 10 is a structural sketch view of a sixth combination manner of the modular cutting element according to an embodiment 6 of the present invention.

(11) FIG. 11 is a structural sketch view of a seventh combination manner of the modular cutting element according to an embodiment 7 of the present invention.

(12) FIG. 12 is a structural sketch view of an eighth combination manner of the modular cutting element according to an embodiment 8 of the present invention.

(13) FIG. 13 is a structural sketch view of the modular cutting-teeth bit (a compact bit comprising a PDC bit and a cone-cutting bit) according to a preferred embodiment of the present invention.

(14) FIG. 14 is a contrast diagram of bit pressure of a three-cone bit to the present invention applied in the PDC bit while drilling hard strata and high abrasive property strata.

(15) FIG. 15 is a contrast diagram of bit pressure of a three-cone bit to the present invention applied in the PDC bit while drilling hard strata and high abrasive property strata.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(16) Embodiment 1: Solution 1 of a Modular Cutting Element

(17) As shown in FIG. 3 of the drawings, a number of the modular unit is 2. Cross-section shapes of a module and the module unit are circles. A diameter of the module is d. Two kinds of modular units are provided. A total number of two modular units are provided, which are respectively a modular unit 1 and a modular unit 2. Diameters of the modular unit 1 and the modular unit 2 are respectively d.sub.1 and d.sub.2. A center distance along a Y axis direction of the modular unit 1 to the modular unit 2 is h.sub.1, wherein

(18) $0h_1\frac{d_1+d_2}{2}.$

(19) Embodiment 2: Solution 2 of the Modular Cutting Element

(20) As shown in FIG. 5 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises the module (1) and the modular unit (2). Cross-section shapes of the module and the modular unit are circles. All the modular units are in the module. A distance is provided between each two modular units. A diameter of the module is d. Two kinds of modular units are provided, wherein a total number of the modular unit is 4. Diameters of the two kinds of modular units are respectively d.sub.1 and d.sub.2.

(21) Embodiment 3: Solution 3 of the Modular Cutting Element

(22) As shown in FIG. 7 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises the module (1) and the modular unit (2). A cross-section of the module is in a racetrack shape. Cross-section shapes of the modular unit comprise circular, rhombus, triangle and rectangle, which are regularly distributed.

(23) Embodiment 4: Solution 4 of the Modular Cutting Element

(24) As shown in FIG. 8 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises a module (1) and modular units (2). A cross-section shape of the module is a hollow ellipse. Cross-section shapes of the modular units are circulars which have different sizes and are irregularly distributed.

(25) Embodiment 5: Solution 5 of the Modular Cutting Element

(26) As shown in FIG. 9 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises a module (1) and modular units (2). The modular units can also be provided with no distance therebetween, i.e., distance values between some of the modular units are 0 mm.

(27) Embodiment 6: Solution 6 of the Modular Cutting Element

(28) As shown in FIG. 10 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises modules (1) and modular units (2). Combination manner thereof are modules of a same kind, wherein a cross-section of the modules are in trapezoid shape.

(29) Embodiment 7: Solution 7 of the Modular Cutting Element

(30) As shown in FIG. 11 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises modules (1) and modular units (2). Combination manner thereof is modules of a different kind, wherein a cross-section of the modules are in a fan shape or a rectangle shape, i.e., a combination of a fan shape and a rectangle shape.

(31) Embodiment 8: Solution 8 of the Modular Cutting Element

(32) As shown in FIG. 12 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises modules (1) and modular units (2). In this combination manner, no distance is provided between the modules, i.e. a distance value of some modules is 0 mm.

(33) Embodiment 9: PDC Bit

(34) As shown in FIG. 1 of the drawings, a modular cutting-teeth drill bit with controllable drilling specific pressure comprises a module (1), a modular unit (2), a bit body (3), a PDC cutting teeth (4) and a nozzle (5), wherein the bit thereof comprises at least one cutting element (see FIG. 2 of the drawings) formed by the module or the modular unit of the present invention, and a plurality of the cutting elements constitute the PDC cutting teeth (4).

(35) Embodiment 10: Compact Bit

(36) As shown in FIG. 13 of the drawings, a compact bit comprises a cone-cutting bit and a modular PDC bit. A modular cutting-teeth drill bit with controllable drilling specific pressure comprises a module (1), modular units (2), a PDC bit body (3), a PDC cutting teeth (4), a nozzle (5) and a cone-cutting bit, wherein the bit thereof comprises at least one cutting element (see FIG. 2 of the drawings) formed by the module or the modular unit of the present invention, and a plurality of the cutting elements constitute the PDC cutting teeth (4).

(37) Embodiment 11: Theoretical Analysis

(38) According to research ideas of the present invention, designs of modular cutting-teeth bit of different solutions can be completed. The solution in the FIG. 3 is chosen for serving as an example for analysis.

(39) As shown in FIG. 3 of the drawings, a number of the modular unit is 2. Cross-section shapes of a module and the module unit are circles. A diameter of the module is d. The two modular units are provided in the two modules. Two kinds of modular units are provided. A total number of two modular units are provided, which are respectively a modular unit 1 and a modular unit 2. Diameters of the modular unit 1 and the modular unit 2 are respectively d.sub.1 and d.sub.2. A center distance along a Y axis direction of the modular unit 1 to the modular unit 2 is h.sub.1, wherein

(40) $0h_1\frac{d_1+d_2}{2}.$

(41) Distribution rules of the cutting-edge length of the cutting element which comprises the module 1 and the modular units 2 in different drilling processes are analyzed as following.

(42) When the module 1 works alone, i.e.,

(43) $0y\left(\frac{d_1}{2}+h_1-\frac{d_2}{2}\right),$
a point of the module 1 is set as (x.sub.1, y.sub.1), the cutting-edge length thereof is calculated as:

(44) $l_{1d_1}=\{\begin{array}{c}{2\left[{\left(\frac{d_1}{2}\right)}^2-{\left(\frac{d_1}{2}-y\right)}^2\right]}^{\frac{1}{2}}\\ 0y\left(\frac{d_1}{2}+h_1-\frac{d_2}{2}\right)\end{array}$

(45) Corresponding to the module having a diameter of d, a cutting-edge length corresponding to the point (x.sub.1, y.sub.1) in FIG. 3 is:

(46) $l_{1^{}d}=\{\begin{array}{c}{2\left[{\left(\frac{d}{2}\right)}^2-{\left(\frac{d}{2}-y\right)}^2\right]}^{\frac{1}{2}}\\ 0y\left(\frac{d_1}{2}+h_1-\frac{d_2}{2}\right)\end{array}$

(47) When the module 1 and the modular unit 2 work together, a point is set as (x.sub.2, y.sub.2), the cutting-edge length thereof is calculated as:

(48) $l_{12d_1{d}_2}=\{\begin{array}{c}2\left\{{\left[{\left(\frac{d_2}{2}\right)}^2-{\left(\frac{d_1}{2}+h_1-y\right)}^2\right]}^{\frac{1}{2}}+{\left[{\left(\frac{d_1}{2}\right)}^2-{\left(y-\frac{d_1}{2}\right)}^2\right]}^{\frac{1}{2}}\right\}\\ \left(\frac{d_1}{2}+h_1-\frac{d_2}{2}\right)<y{d}_1\end{array}$

(49) Corresponding to the cutting element having the diameter of d, a cutting-edge length corresponding to the point (x.sub.2, y.sub.2) in FIG. 3 is:

(50) $l_{1^{}{2}^{}d}=\{\begin{array}{c}{2\left[{\left(\frac{d}{2}\right)}^2-{\left(\frac{d}{2}-y\right)}^2\right]}^{\frac{1}{2}}\\ \left(\frac{d_1}{2}+h_1-\frac{d_2}{2}\right)<y{d}_1.\end{array}$

(51) When the modular unit 2 works alone, i.e.,

(52) $d_1<y\left(\frac{d_1}{2}+h_1+\frac{d_2}{2}\right),$
a point thereof is set as (x.sub.3, y.sub.3), and the cutting-edge length thereof is calculated as:

(53) $l_{3d_2}=\{\begin{array}{c}{2\left[{\left(\frac{d_2}{2}\right)}^2-{\left(\frac{d_1}{2}+h_1-y\right)}^2\right]}^{\frac{1}{2}}\\ d_1<y\left(\frac{d_1}{2}+h_1+\frac{d_2}{2}\right).\end{array}$

(54) Corresponding to the cutting element having the diameter of d, a cutting-edge length corresponding to the point (x.sub.3, y.sub.3) in FIG. 3 is:

(55) 0$l_{3^{}d}=\{\begin{array}{c}{2\left[{\left(\frac{d}{2}\right)}^2-{\left(\frac{d}{2}-y\right)}^2\right]}^{\frac{1}{2}}\\ d_1<y\left(\frac{d_1}{2}+h_1+\frac{d_2}{2}\right).\end{array}$

(56) Comparative Analysis of the Cutting Edge Lengths

(57) Corresponding to a same radial depth (coordinate value along a Y axis, l.sub.1d, l.sub.1d.sub.1, l.sub.12d, l.sub.12d.sub.1.sub.d.sub.2, l.sub.3d and l.sub.3d.sub.2 which are respectively cutting edge lengths of diameters d, d.sub.1 and d.sub.2 are compared as shown in FIG. 3 of the drawings.

(58) Analysis result of the module and the modular unit shows that compared with the conventional cutting element, the modular cutting-teeth bit controls effective abrasion edge length of the cutting element on a certain portion thereof, and maintains a constant specific pressure of the cutting element of the bit during the drilling process by controlling a combination of shapes, sizes and numbers of the module and the modular unit is optimized; effective abrasion edge length of the cutting element on a certain portion thereof. According to relationship among the cutting-edge length, the specific pressure and the ROP, increase of the cutting-edge length dramatically reduces breaking efficiency of the rocks the ROP. By controlling the cutting-edge length, thus, the specific pressure still maintains a greater drilling depth corresponding to the bit pressure and properties of the rocks, so as to ensure penetration of the cutting element and realize improving the ROP of the bit.

(59) Embodiment 12

(60) A modular PDC bit manufactured according to designing of the present invention having a size of 8.5, a number of blade wings thereof is 6, and a diameter of a main cutting tooth is 16 mm.

(61) Actual data in drilling process:

(62) (1) well section utilized: 2879 m2965 m;

(63) (2) lithology: light gray fine-grained sandstone and medium-grained sandstone (quartz-bearing), grayish white medium-grained sandstone (quartz-bearing) and black carbonaceous shale;

(64) (3) Bit pressure: 6070 KN;

(65) (4) Rotating speed: 6075 rpm;

(66) (5) Displacement: 421/m;

(67) (6) Average ROP: 6.33 m/h.

(68) As shown in FIG. 14 and FIG. 15 of the drawings, results of the embodiments show that compared with a three-cone bit, the modular cutting-teeth bit greatly reduced drilling pressure while drilling hard strata and high abrasive strata, and ROP thereof is significantly improved and remains stable.

(69) One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

(70) It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.