Rotating cutter single cone bit

Abstract

A rotating cutter single cone bit includes a bit body and a cone that is rotatably coupled to the bit body. Cutters are arranged on the cone. At least one cutter on the cone is a rotating cutter. The rotating cutter forms a rotational connection with the cone. The geometric center of the front cutting face of the rotating cutter or the front cutting face of the rotating cutter is offset from the rotating axis of the rotating cutter, and the geometric center of the rear cutting face or the rear cutting face of the rotating cutter is on the same side of the offset of the front cutting face. The front cutting face is closer to the rotating axis of the rotating cutter than the rear cutting face. The rotating cutter is rotatable about the rotating axis of the rotating cutter on the cone.

Claims

1. A rotating cutter single cone bit, comprising: a bit body; a cone that is rotatably coupled to the bit body; and a plurality of cutters arranged on the cone, wherein at least one of the plurality of cutters on the cone is a rotating cutter having a rotational connection with the cone, wherein a rotational axis of the rotating cutter resides in an imaginary plane that divides the rotating cutter into a first side and a second side, wherein a geometric center of a front cutting face of the rotating cutter or the front cutting face of the rotating cutter resides in the first side, and a geometric center of a rear cutting face or the rear cutting face of the rotating cutter resides in the first side, and wherein a distance between the front cutting face and the rotational axis of the rotating cutter is less than a distance between the rear cutting face and the rotational axis of the rotating cutter.

2. The rotating cutter single cone bit of claim 1, wherein the rotating cutter comprises a rotating shaft rotatably coupled to the cone, and one or more cutting elements affixed to the rotating cutter, wherein the one or more cutting elements are selected from a polycrystalline diamond compact (PDC), a polycrystalline diamond composite cutter, a thermostable polycrystalline diamond cutter, an impregnated diamond cutter, a cubic boron carbide cutter, a ceramic cutter, a polycrystalline diamond and impregnated diamond phase composite cutter, or a combination thereof, wherein, when the one or more cutting elements are the polycrystalline diamond compact, the polycrystalline diamond composite cutter, or the polycrystalline diamond and impregnated diamond composite cutter, the one or more cutting elements are oriented so that a front end face of the polycrystalline diamond layer of the one or more cutting elements is the front cutting face.

3. The rotating cutter single cone bit of claim 2, wherein the distance between the geometric center of the front cutting face or the front cutting face of the rotating cutter and the rotational axis of the rotating cutter is more than one eighth of a radius of the rotating shaft and less than twice the radius of the rotating shaft.

4. The rotating cutter single cone bit of claim 2, wherein a total number of the one or more cutting elements affixed to the rotating cutter ranges from 1 to 6.

5. The rotating cutter single cone bit of claim 2, further comprises a locking structure disposed between the rotating shaft of the rotating cutter and the cone and restricts a movement of the rotating cutter in the direction of the rotational axis.

6. The rotating cutter single cone bit of claim 5, wherein the locking structure is a ball locking.

7. The rotating cutter single cone bit of claim 2, further comprising a sealing structure disposed between the rotating shaft of the rotating cutter and the cone.

8. The rotating cutter single cone bit of claim 2, further comprising a bushing disposed between the rotating shaft of the rotating cutter and the cone.

9. The rotating cutter single cone bit of claim 8, wherein the bushing and the rotating shaft of the rotating cutter are rotationally coupled.

10. The rotating cutter single cone bit of claim 1, wherein a distance between the geometric center of the front cutting face of the rotating cutter is between 1 and 32 mm.

11. The rotating cutter single cone bit of claim 1, wherein the rotating cutter is arranged on a constant contact area of the cone or an alternating contact area of the cone.

12. The rotating cutter single cone bit of claim 1, wherein a line passing through the geometric center of the front cutting face of the rotating cutter intersects the rotational axis of the rotating cutter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1 and 2 are schematic illustrations of embodiment 1 of the present disclosure.

(2) FIG. 3 is a schematic illustration of a rotating cutter scraping rock in embodiment 1 of the present disclosure.

(3) FIG. 4 is a schematic illustration of a rotating shaft of a rotating cutter in embodiment 1 of the present disclosure in the form of a journal with a step.

(4) FIG. 5 is a schematic illustration of a cylindrical rotating shaft of a rotating cutter according to embodiment 1 of the present disclosure.

(5) FIGS. 6 and 7 are schematic illustrations of two cutting elements on the rotating cutter of embodiment 1 of the present disclosure.

(6) FIG. 8 is a schematic illustration of a locking structure and a sealing structure arranged between the rotating cutters and the cone in embodiments 4 and 5 of the present disclosure.

(7) FIG. 9 is a schematic illustration of contact area division of the cone in contact with the rock at the bottom of the well.

(8) FIG. 10 is a schematic illustration of conventional PDC cutter structure.

(9) FIG. 11 is a schematic illustration of normal scraping of rock by conventional PDC cutters.

(10) FIGS. 12, 13 and 14 are schematic illustrations of the cutting elements on the rotating cutters of embodiment 1 of the present disclosure, which are semi-cylindrical, wedge-shaped and vertically arranged respectively.

(11) FIG. 15 is a schematic illustration of a bushing between a rotating cutter and a cone in embodiment 6 of the present disclosure.

(12) In the figures, the numeral 1 is the bit body; the numeral 2 is the cone; the numeral 21 is the constant contact area; the numeral 22 is the alternating contact area; the numeral 3 is the rotating cutters; the numeral 31 is the PDC cutter substrate; the numeral 32 is the polycrystalline diamond layer of PDC cutter; the numeral 33 is the front cutting face of rotating cutters; the numeral 34 is the rotating axis of rotating cutters; the numeral 35 is the rear cutting face of rotating cutters; the numeral 36 is rotating shaft of rotating cutters; the numeral 37 is the back of front cutting face of rotating cutters; the numeral 4 is the rock; the numeral 5 is the sealing structure; the numeral 6 is the locking structure; the numeral 7 is the bushing.

Embodiments

(13) The following non-limiting embodiments are used to illustrate the present disclosure.

Embodiment 1

(14) As illustrated in FIGS. 1-3: a rotating cutter single cone bit, which comprises a bit body 1 and a cone 2 that is rotatably coupled to the bit body 2, cutters are arranged on the cone 2, and at least one cutter on the cone 2 is a rotating cutter 3, the rotating cutter 3 forms a rotational connection with the cone 2. As a choice, as shown in the present embodiment, the rotating cutter 3 includes a rotating shaft 36 rotatably coupled to the cone 2, and a cutting element fixed on the rotating shaft 36. There is a shaft hole on the cone 2 corresponding to the rotating shaft 36 which contains the matching rotating cutter 3. The rotating shaft 36 is inserted into the shaft hole and can rotates on the cone 2. The rotating shaft 36 can take many forms. For example, FIGS. 4 and 7 show that the rotating shaft 36 of the rotating cutter 3 is a step journal, and FIGS. 5 and 6 show that the rotating shaft 36 of the rotating cutter 3 is a cylindrical shape. The cutting element is fixed on the top surface of the rotating shaft 36, and the front face (front end face of wear-resistant layer) of the cutting element forms an angle with the top surface of the rotating shaft 36. Consolidation between cutting elements and rotating shaft 36 can also take many forms. For example, as shown in FIGS. 4 and 5, part of the substrate and the side of the wear-resistant layer are trapped and fixed in the top surface; or as shown in FIGS. 6 and 7, a convex platform is formed in the top surface, and the side of the surface part is trapped and fixed in the convex platform, while the wear-resistant layer is exposed outside the convex platform. The geometric center of the front cutting face 33 of the rotating cutter 3 or the front cutting face 33 of the rotating cutter 3 is offset from the rotating axis 34 of the rotating cutter 3, and the geometric center of the rear cutting face 35 or the rear cutting face 35 of the rotating cutter 3 is on the same side of the offset of the front cutting face 33. The front cutting face 33 is closer to the rotating axis 34 of the rotating cutter 3 than the rear cutting face 35. The rotating cutter 3 is rotatable about the rotating axis 34 of the rotating cutter on the cone 2.

(15) As a choice, the cutting elements on the rotating cutter 3 may be polycrystalline diamond compact, polycrystalline diamond composite cutters, thermostable polycrystalline diamond composite cutters, impregnated diamond cutters (blocks), cubic boron carbide, ceramic cutters, or polycrystalline diamond and impregnated diamond phase composite. As a further choice, the cutting elements on the rotating cutter 3 are polycrystalline diamond compact. Polycrystalline diamond compact consists of a polycrystalline diamond layer 32 and a substrate 31 (as shown in FIG. 10). The front end surface of the polycrystalline diamond layer 32 is the front cutting face 33 of the cutting element, and the side surface is the rear cutting face 35 (as shown in FIG. 3). As a choice, the shape of the cutting element on the rotating cutter 3 is semi-cylindrical (as shown in FIG. 12), wedge-shaped (as shown in FIG. 13) or vertically arranged cylindrical (as shown in FIG. 14), etc. As a choice, the offset S of the geometric center O of the front cutting face 33 of the rotating cutter 3 or the front cutting face 33 of the rotating cutter 3 to the rotating axis 34 of the rotating cutter 3 is greater than one eighth of the radius of the rotating shaft 36, and less than twice the radius of the rotating shaft 36 (as shown in FIGS. 3 and 8). As a further choice, the offset S is between 1 and 32 mm. The number of cutting elements on the rotating cutter 3 may be one or more. As a choice, the number of cutting elements on the rotating cutter 3 is 1-6. As a further choice, the number of cutting elements on the rotating cutter 3 is one (as shown in FIGS. 1, 2), two (as shown in FIGS. 6, 7) or three. When the cutting element is one, it is preferable that the normal of the geometric center of the front cutting face of the rotating cutter intersects with its rotating axis. When the cutting elements are more than one, the front cutting faces 33 of each cutting elements are arranged side by side toward the rotating axis 34, and are distributed to the left and right with respect to the rotating axis 34.

Embodiment 2

(16) Referring to FIGS. 1, 2, and 9, the present embodiment is substantially the same as Embodiment 1. The difference is that the rotating cutters 3 are arranged on the constant contact area 21 of the cone 2.

Embodiment 3

(17) Referring to FIGS. 1, 2, and 9, the present embodiment is substantially the same as Embodiment 2. The difference is that the rotating cutters 3 are arranged on the alternating contact area 22 of the cone 2.

Embodiment 4

(18) Referring to FIG. 8, the present embodiment is substantially the same as Embodiment 1. The difference is that a locking structure 6 for restricting the movement of the rotating cutter 3 relative to the cone 2 in the direction of the rotating axis 34 is provided between the rotating shaft of the rotating cutter 3 and the cone 2.

Embodiment 5

(19) Referring to FIG. 8, the present embodiment is substantially the same as Embodiment 1. The difference is that a sealing structure 5 is disposed between the rotating cutter 3 and the cone 2.

Embodiment 6

(20) Referring to FIG. 15, the present embodiment is substantially the same as Embodiment 1. The difference is that a bushing 7 is provided between the rotating cutter 3 and the cone 2. As a choice, the bushing 7 and the cone 2 are relatively tightened. The bushing 7 and the cone 2 can be tightened by interference fit, welding, etc. The bushing 7 and the rotating shaft of the rotating cutter 3 are rotationally coupled.

(21) The disclosure has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the disclosure as hereinafter claimed, and legal equivalents thereof.