CN101899952B

CN101899952B - Drilling tool

Info

Publication number: CN101899952B
Application number: CN200910253060.3A
Authority: CN
Inventors: 瑞德哈·察法; 詹姆斯·华莱士
Original assignee: ReedHycalog UK Ltd
Current assignee: ReedHycalog UK Ltd
Priority date: 2008-10-09
Filing date: 2009-10-09
Publication date: 2014-01-15
Anticipated expiration: 2029-10-09
Also published as: AU2009222620A1; GB2464194A; AU2009222620B2; GB0917279D0; CN101899952A; GB2464194B

Abstract

A drilling tool comprises a body having a main drilling region and a pilot drilling region eccentric to the main drilling region, the main drilling region including a plurality of main blades and the pilot drilling region including a plurality of pilot blades, the main drilling region having a main pass through diameter, centered upon a first axis, at least one of the main blades extending to the main pass through diameter, the pilot region having a pilot gauge diameter, centered upon a second axis of rotation at least one of the pilot blades extending to the pilot gauge diameter, wherein part of a circle of diameter equal to the pilot gauge diameter and centered upon the second axis of rotation extends outside of a circle of diameter equal to the main pass through diameter and centered upon the first axis.

Description

Drilling tool

Technical field

The present invention relates to a kind of drilling tool, a kind of rotatable drilling tool for well probing particularly, for example, subsequently for extracting oil or natural gas.

Background technology

In well, expectation comprises the region that diameter increases sometimes.Obviously, if get out the part that diameter is relatively large below smaller diameter portion, the drill bit that can partly hole to major diameter so must assign to install by smaller diameter portion.The auger of one type using in this application comprises many moving-members, to allow to increase effective bore diameter of drill bit.The drill bit of the another type of using in such application is bicenter bit.Such drill bit is designed, to allow it to drive around two different rotations.Drill bit causes drill bit to creep into maybe around the rotation of the first central axis or support can be through the hole of minor diameter relatively, and drill bit causes getting out larger-diameter hole around the rotation that is eccentric in the second axis of drill main body.Being centered close on the second eccentric rotary axis of the guiding of drill bit (pilot) region, in order to bore guide hole, the parts of drill bit engage with the wall of guide hole for steady drill bit.

For maximum stability, expectation guiding area has major diameter.Yet the size that increases guiding area causes two axial lines considerably close to each other, has reduced the maximum gauge that can be holed for the instrument of intended size.

EP0058061 has described two centre-drilling hole drill bits of the general type above summarized.Similar layout has been shown in GB2351513, US6394200, EP1085167, EP1039095 and US2004/0099448.

An object of the present invention is to provide a kind of drilling tool that overcomes the shortcoming above set forth or reduce its effect.

Summary of the invention

According to the present invention, a kind of drilling tool is provided, it comprises the main body that has main borehole region and be eccentric in the pilot hole region in main borehole region, main borehole region comprises a plurality of main blades, pilot hole region comprises a plurality of guide blade, the primary path diameter of main borehole region centered by limiting on first axle, at least one main blade extends to primary path diameter, guiding area limits the guiding format diameter (gauge diameter) centered by the second rotation, at least one guide blade extends to guiding format diameter, wherein, the diameter outside that the part of format diameter and the circumference centered by the second rotation equals primary path diameter and the circumference centered by first axle at diameter that equals to lead is spaced apart.

Preferably, at least one guide blade is shorter than guiding format diameter, only extends to a part for primary path diameter.

The advantage of such setting is, guiding area can have the diameter of increase, thereby benefits from the stability of enhancing and the drilling tool size of increase, meanwhile, allows relatively large diameter bore region to be holed.

Should be appreciated that diameter equals to lead the circumference of format diameter and circumference that diameter equals primary path diameter two isolated intersection.Preferably, blade is arranged on described in each on position, and these blades are convenient to simultaneously as main blade and guide blade.

Main blade is convenient to be interconnected with one another by many gauge pads (gauge pad).Flow channel is preferably arranged on the below of gauge pad to allow fluid to flow through.Preferably, gauge pad limits gauge ring (gauge ring) together with blade.Gauge ring is preferably circular cross section, but the position that preferably includes the ，Gai region, region with different curvature radius is relative on diameter with the position of described at least one guide blade that is shorter than described guiding format diameter.

Accompanying drawing explanation

With reference to accompanying drawing, by way of example, the present invention is further described, wherein:

Fig. 1 is the diagram of the bicenter bit of prior art;

Fig. 2 is the diagram of drill bit according to an embodiment of the invention;

Fig. 3 is the end-view that the drill bit in Fig. 2 is shown;

Fig. 4 is the diagram that the operation of the drill bit in Fig. 2 is shown;

Fig. 5 a and 5b are the diagrams of drill bit in use; With

Fig. 6 is the view that is similar to accompanying drawing 3, but alternative embodiment is shown.

The specific embodiment

First with reference to figure 1, show bicenter bit of the prior art, it comprises the drill main body 10 that limits main borehole region 12 and pilot hole region 14.Drill main body 10 also comprises mount pin region 16, and drill bit can be fixed on other the downhole tool of support drill bit thus, allows weight (weight-on-bit) load on drill bit to be applied on drill bit, and allows drill bit to be actuated to be rotated.

The main borehole region 12 of drill main body 10 comprises a plurality of upright blades 18 (only is visible), and a plurality of cutting elements 20 are installed on each blade, for example, become the form of the small-sized cutting element of polycrystalline diamond.At least some blades 18 extend out to primary path diameter 22, its be centered close to pivot center 26 biasing of drill bit or eccentric axis 24 on.

Pilot hole region 14 also comprises a plurality of upright blades 28, and it is the same with the blade 18 in main borehole region 12, carries a plurality of cutting elements 20.The blade 28 in pilot hole region 14 extends out to guiding format diameter 30 away from rotation 26, and it is centered by rotation 26.As being clear that from accompanying drawing 1, diameter equals to lead the guiding rule footpath circumference (gauge circle) of format diameter 30 centered by rotation 26, and is positioned at diameter completely and equals primary path diameter 22 and be centered close to the path circumference on axis 24.

In use, when drill bit rotates around its rotation 26, on drill bit, mass loading is applied thereto, and the Kong，Gai hole that causes pilot hole region 14 to get out relative minor diameter is broadened or is extended by main borehole region 12 afterwards.Main borehole region 12 is larger than the diameter in pilot hole region 14, and be also arranged to and its bias, result is, the diameter in hole of completion is greater than the diameter of guide hole significantly, and the radius in the hole of completion is substantially equal to from rotation 26 to away from the radial distance at the blade 18 edge in the main borehole region 12 of rotation 26.In such hole expansion process, the guiding area 14 of drill bit and the joint between the wall of guide hole, for steady drill bit, thereby react on the lateral action load being applied thereto that the blade 18 by main borehole region 12 produces with respect to rotation 26 arranged off-centre.

Although can get out relatively large diameter hole, bicenter bit can creep into or pass very little hole of diameter, and drill bit can equal through diameter the opening of primary path diameter 22.

As mentioned above, such layout has such shortcoming: can use the maximum gauge stability relatively little and drill bit of the down-hole equipment of described drill bit to be on duty mutually.

According to one embodiment of present invention, with reference to figure 2-5, drill bit comprises drill main body 50, the form of cast steel for example, and it limits main borehole region 52 and pilot hole region 54.Arrange as is known, each arranges a series of

upright blade

56 and 58 main borehole region and

pilot hole region

52,54, and each in blade carried a plurality of cutting elements 60.Drill main body 50 also comprises mount pin (not shown), and it can be connected on other down-hole equipment thus, with allow expectation position upper support drill bit, with mass loading on drill bit is applied on it and transferring rotational motion to drill bit.

As described above, main borehole region 52 comprises a plurality of main blades 56 (not shown in accompanying drawing 4), and at least some in main blade 56 extend out on the path circumference 68 with passage diameters.

Also as described above, pilot hole region 54 has a plurality of guide blade 58.On the rotation that is centered close to drill bit 64 in pilot hole region 54, and most guide blade 58 extends to the guiding rule footpath circumference 65 with guiding format diameter 66 away from rotation 64.Being centered close on rotation 65 of guiding rule footpath circumference 65.Path circumference 68 be centered close to the isolated axis 72 of rotation 64 on, diameter 66,70 makes a part 74 for guiding rule footpath circumference 65 be projected into the outside of path circumference 68.Although most of guide blade 58 extends on guiding rule footpath circumference 65, one (being represented by digital 58a) in guide blade extends along the direction beyond the circumference 65 outstanding path circumference 68 of guiding rule footpath, this blade 58a is shorter than or does not arrive guiding format diameter 66, only extends to path circumference 68.Although only have in this embodiment a blade 58a to arrange like this, but below arrange it is possible, wherein: the blade 58a of two or more extends along the direction beyond the circumference 65 outstanding path circumference 68 of guiding rule footpath, and in such layout, each blade 58a is shorter than or does not arrive guiding format diameter 66, only extends to path circumference 68.

Should be appreciated that by the guide blade 58a of shortening is included in this part of drill bit, can obtain relatively large guiding format diameter 66.As a result, can improve the stability of drill bit.Can obtain these advantages, and not increase the size of passage diameters and do not reduce the maximum drilling diameter of drill bit.As Fig. 5 a and 5b illustrate respectively, drill bit is for holing to relatively large diameter drilling well region, region through relative minor diameter, from these accompanying drawings, can clearly be seen that, although drill bit has relatively large guiding format diameter, compare with typical layout, the present invention still allows to form the boring region having than the large many diameters of the passage diameters of drill bit.

Guiding rule footpath circumference 65 intersects with path circumference 68 at two point 76 places, and as the blade of guide blade and

main blade

56,58, is positioned at these easily simultaneously and puts on 76.The advantage of such layout is, the stability of stability, particularly guiding area is enhanced, because these blades provide and the contact point of earth formation of either side of targeting part near being provided with the blade 58a of shortening.Preferably, put 76 enough distances that are spaced apart from each other, making them is 80-130 ° in the relative angle in axis 64 places, preferably approximately 100 °.

Next, with reference to figure 6, show a kind of alternative layout.Because identical or very similar with Fig. 3 of the major part in Fig. 6, so be only described in detail marked difference here.

In the layout of Fig. 6, be provided with a plurality of gauge pads 80, each gauge pad 80 interconnects two adjacent main blades in main blade 56, strides across the groove 82 forming between it.Gauge pad 80 defines continuous gauge ring 86 jointly with the adjacent part of main blade 56.Although not shown, the gage surface of gauge ring can be provided with applicable wear-resistant coating or insert.In addition,, although diagram is continuous, if needed, gauge ring 86 can be the discontinuous form of part circumference.Flow channel 84 be formed on gauge pad 80 below, between gauge pad 80 and main body 50, allow fluid to flow through gauge ring 86 along groove 82.

Gauge ring 86 is circular, but can comprise the region 88 being oppositely arranged from blade 58a, have different (preferably larger) diameters.Similarly, in the layout of Fig. 2-5, blade 56 can be shorter than path circumference 68 in this region.

Although drill bit is described above, should be appreciated that the present invention also can be applicable to the drilling tool of other type, as reamer (reamer) etc.In addition, should be appreciated that in the situation that not departing from the scope of the invention, can carry out various modifications and replacement to layout described herein.

Claims

1. a drilling tool, it comprises: have main borehole region and with the main body in the pilot hole region of described main borehole region bias, described main borehole region comprises a plurality of main blades, described pilot hole region comprises a plurality of guide blade, described main borehole region limits the primary path diameter centered by first axle, at least one in described main blade extends to described primary path diameter, described pilot hole region limits the guiding format diameter centered by the second axis, at least one in described guide blade extends to described guiding format diameter, wherein, diameter equals the outside that the part of described guiding format diameter and the circumference centered by described the second axis equals described primary path diameter and the circumference centered by described first axle at diameter and is spaced apart, wherein diameter equals the described circumference of described guiding format diameter and described circumference that diameter equals described primary path diameter two isolated intersection, described in each, isolated position is provided with a guide blade in described guide blade.

2. drilling tool as claimed in claim 1, at least one guide blade in wherein said guide blade is shorter than described guiding format diameter, only extends to a part for described primary path diameter.

3. drilling tool as claimed in claim 1, was wherein not only positioned at isolated position described in each as main blade but also as the blade of guide blade.

4. drilling tool as claimed in claim 3, wherein said isolated position with 80-130 ° of angle facing to described the second axis.

5. drilling tool as claimed in claim 4, wherein said isolated position with 100 ° of angles facing to described the second axis.

6. drilling tool as claimed in claim 1, wherein adjacent main blade connects each other by a series of gauge pads.

7. drilling tool as claimed in claim 6, also comprises the flow channel that is arranged on described gauge pad below, to allow fluid to pass through.

8. drilling tool as claimed in claim 6, wherein said gauge pad and main blade limit gauge ring jointly.

9. drilling tool as claimed in claim 8, wherein said gauge ring is substantially circular cross section, but the position that comprises the ，Gai region, region with different curvature radius is relative on diameter with the position of described at least one guide blade that is shorter than described guiding format diameter.