CN101899952A

CN101899952A - Drilling tool

Info

Publication number: CN101899952A
Application number: CN2009102530603A
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: 2010-12-01
Anticipated expiration: 2029-10-09
Also published as: GB0917279D0; AU2009222620B2; CN101899952B; GB2464194A; GB2464194B; AU2009222620A1

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, particularly a kind of rotatable drilling tool that is used for the well probing for example is used to extract oil or natural gas subsequently.

Background technology

Expectation comprises the zone that diameter increases sometimes in well.Obviously, if below smaller diameter portion, get out the big relatively part of diameter, can must assign to install by smaller diameter portion to the drill bit that major diameter is partly holed so.One type the auger that uses in this application comprises many moving-members, to allow to increase effective bore diameter of drill bit.The drill bit of employed another type is a bicenter bit in such application.Such drill bit is designed, and can drive around two different rotations to allow it.Drill bit causes drill bit to creep into maybe can passing relatively than the hole of minor diameter around the rotation of first central axis or support, and drill bit causes getting out larger-diameter hole around the rotation of second axis that is eccentric in drill main body.Being centered close on the second eccentric rotation of the guiding of drill bit (pilot) zone, in order to bore guide hole, the parts of drill bit engage with the wall of guide hole and are used for stablizing drill bit.

For the stability of maximum, the 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 of above being summarized.In GB2351513, US6394200, EP1085167, EP1039095 and US2004/0099448, similar arrangements has been shown.

An object of the present invention is to provide and a kind ofly overcome above the shortcoming of being set forth or the drilling tool that reduces 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 the main borehole zone and be eccentric in the pilot hole zone in main borehole zone, the main borehole zone comprises a plurality of main blades, the pilot hole zone comprises a plurality of guide blade, the main borehole area limiting is on the first axle to be the primary path diameter at center, at least one main blade extends to the primary path diameter, it is the guiding format diameter (gauge diameter) at center that guiding area limits with second rotation, at least one guide blade extends to the guiding format diameter, wherein, diameter equal to lead format diameter and be that the part of the circumference at center equals the primary path diameter and is that the outside of circumference at center is spaced apart with the first axle at diameter with second rotation.

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

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

Should be appreciated that diameter equal the to lead circumference of format diameter and the circumference that diameter equals the primary path diameter intersects at two spaced positions places.Preferably, blade is set on each described 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 guarantor's footpath pads (gauge pad).Flow channel preferably is arranged on the below of protecting the footpath pad and flows through to allow fluid.Preferably, protect footpath pad and blade and limit guarantor's footpath ring (gauge ring) together.Protect the footpath ring and be preferably the circular cross section, but preferably include the zone with different curvature radius, this regional position is relative on diameter with the position of described at least one guide blade that is shorter than described guiding format diameter.

Description of drawings

With reference to the accompanying drawings, by way of example, the present invention has been carried out further description, 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 among Fig. 2 is shown;

Fig. 4 is the diagram that the operation of the drill bit among 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

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

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

In use, when drill bit rotated around its rotation 26, mass loading was applied thereto on the drill bit, causes pilot hole zone 14 to get out the hole of relative minor diameter, and this hole is broadened by main borehole zone 12 afterwards or extends.Main borehole zone 12 is bigger than the diameter in pilot hole zone 14, and also be arranged to and its off-centre, the result is, the diameter in the hole of completion is significantly greater than the diameter of guide hole, and the radius in the hole of completion is substantially equal to from rotation 26 to away from the radial distance at the edge of the blade 18 in the main borehole zone 12 of rotation 26.In such hole expansion process, joint between the guiding area 14 of drill bit and the wall of guide hole, be used for stablizing drill bit, thereby react on the side direction used load that is applied thereto that the blade 18 by main borehole zone 12 is produced with respect to rotation 26 arranged off-centre.

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

As mentioned above, such layout has such shortcoming: promptly can use relatively little and stability drill bit of the maximum gauge of 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 zone 52 and pilot hole zone 54.Arrange that as is known each is provided with a series of

upright blade

56 and 58 main borehole zone and

pilot hole zone

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

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

Also as indicated above, pilot hole zone 54 has a plurality of guide blade 58.On the rotation that is centered close to drill bit 64 in pilot hole zone 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 the rotation 65 of guiding rule footpath circumference 65.Path circumference 68 be centered close to rotation 64 isolated axis 72 on, diameter 66,70 makes the parts 74 of guiding rule footpath circumference 65 be projected into the outside of path circumference 68.Though most of guide blade 58 extends on the circumference 65 of guiding rule footpath, one (being represented by digital 58a) in the 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 no show guiding format diameter 66, only extends to path circumference 68.Although have only a blade 58a to be provided with so in this embodiment, but following layout is possible, wherein: two or more blade 58a extend along the direction beyond the circumference 65 outstanding path circumference 68 of guiding rule footpath, and each blade 58a is shorter than or no show guiding format diameter 66 in such layout, only extends to path circumference 68.

Should be appreciated that the guide blade 58a by shortening is included in this part of drill bit, can obtain big relatively 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.Illustrate respectively as Fig. 5 a and 5b, drill bit is used for being holed in large diameter relatively drilling well zone, pass the zone of relative minor diameter, can clearly be seen that from these accompanying drawings, although drill bit has big relatively guiding format diameter, compare with typical layout, the present invention still allows to form the boring zone with diameter more many greatly than the passage diameters of drill bit.

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

main blade

56,58 simultaneously easily 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 near the either side of the targeting part of the blade 58a that is provided with shortening.Preferably, point 76 enough distances that are spaced apart from each other make that they are 80-130 ° in the relative angle in axis 64 places, preferably about 100 °.

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

In the layout of Fig. 6, be provided with a plurality of guarantors footpath and fill up 80, each is protected, and directly filling up 80 interconnects two adjacent main blades in the main blade 56, strides across the groove 82 that forms between it.Protecting the footpath fills up 80 and defines continuous guarantor jointly with the adjacent part of main blade 56 and directly encircle 86.Although not shown, the gage surface of protecting the footpath ring can be provided with suitable wear-resistant coating or insert.In addition, though diagram is continuous, if desired, protecting and directly encircle 86 can be the discontinuous form of part circumference.Flow channel 84 be formed on protect the footpath fill up 80 following, protect the footpath fill up 80 and main body 50 between, allow fluid to flow through and protect the footpath and encircle 86 along groove 82.

Protecting and directly encircling 86 is circular, but can comprise the zone 88 that is oppositely arranged with blade 58a, have different (preferably bigger) diameters.Similarly, in the layout of Fig. 2-5, blade 56 can be shorter than path circumference 68 in this zone.

Although above drill bit is being described, 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 under the situation that does not depart from the scope of the invention, can carry out various modifications and replacement layout described herein.

Claims

1. drilling tool, it comprises: have main borehole zone and with the main body in eccentric pilot hole zone, described main borehole zone, described main borehole zone comprises a plurality of main blades, described pilot hole zone comprises a plurality of guide blade, described main borehole area limiting is the primary path diameter at center with the first axle, in the described main blade at least one extends to described primary path diameter, it is the guiding format diameter at center that described guiding area limits with second axis, in the described guide blade at least one extends to described guiding format diameter, wherein, diameter equals described guiding format diameter and equals described primary path diameter and be that the outside of the circumference at center is spaced apart with described first axle at diameter with the part of described second axis circumference that is the center.

2. instrument as claimed in claim 1, at least one in the wherein said guide blade are shorter than described guiding format diameter, only extend to the part of described primary path diameter.

3. instrument as claimed in claim 1 or 2, wherein diameter equals the described circumference that described circumference and diameter with described guiding format diameter equal described primary path diameter and intersects at two spaced positions places, is provided with guide blade in each described position.

4. instrument as claimed in claim 3 wherein not only was positioned at each described position as main blade but also as the blade of guide blade.

5. as claim 3 or 4 described instruments, wherein said position faces toward described second axis with 80-130 ° of angle.

6. the instrument shown in claim 5, wherein said position with 100 ° of angles facing to described second axis.

7. each described instrument in the claim as described above, wherein adjacent main blade is by the connection each other of a series of guarantor footpath pad.

8. instrument as claimed in claim 7 also comprises being arranged on the described flow channel of protecting pad below, footpath, passes through to allow fluid.

9. as claim 7 or 8 described instruments, wherein said guarantor directly fills up with blade and limits guarantor footpath ring jointly.

10. as each the described instrument among the claim 7-9, wherein said guarantor footpath ring is substantially circular cross section, but comprise the zone with different curvature radius, this regional position is relative on diameter with the position of described at least one guide blade that is shorter than described guiding format diameter.