DE60100727T2 - Multi-directional cutting elements for bi-central drilling tools for drilling a casing shoe - Google Patents

Description

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to generally drill bits and especially multi-directional bits for a bi-center boring drill bit fixed chisels.

2. DESCRIPTION OF TECHNICAL RELATED

In an effort to extract minerals wells to drill into the earth, there are cases where whom it is desirable is a borehole with a diameter larger. than the drill bit itself drill. drill bit that are used to form these boreholes are common as a bi-central drill bit known.

Bicentral drill bits are well known in the drilling industry. Different types of bi-center drill bits are available in U.S. Patent Nos. 1,587,266, 1,758,773, 2,074,951, 2,953,354, 3 367 430, 4 408 669, 4 440 244, 4 635 738, 5 040 621, 5 052 503, 5 165 494, 5 678 644 and the European Patent application 0 058 061 described.

Modern bi-central drill bits are becoming typically in difficult drilling applications where the earth formations are difficult to break through where there is a bulging hole where the borehole has a tendency to spiral be used, or in other situations where a hole with oversize desirable is.

With these difficult drilling applications the top section of the borehole often by setting and cementing stabilized by feeding ear. The cement, the shoe, the float and the connected cementing machines are then typically drilled from the chuck pipe using a drill bit, which is inserted into the feeding tube for this purpose. Once the Cement and associated equipment are drilled out, the drill bit is moved out of the hole, and a bicentral drill bit is retracted into the borehole. The drilling is afterwards continued with the bi-central drill bit, a hole with a diameter in the formation under the casing drills larger than the inner diameter of the casing.

To reduce drilling costs, Attempts have been made to use a single bi-central drill bit to drill the cement and associated equipment from the casing and then drill the formation under the casing. These attempts led often severe damage both the casing and the bi-central drill bit.

The feeding ear tends to go through the on the bi-central drill bit attached caliber cutting elements to be damaged as the guide section of the drill bit is forced inside the casing to its center orbit what causes the caliber chisel interlock with the feeding ear. The forced orbital movement of the guide section can also damage the chisel on the front surface of the bi-central drill bit cause.

As is well known, have with drill bits fixed chisels the cutting elements cutting surfaces, the in proportion to the direction of movement of the chisel be precisely aligned by the formation to be drilled. however experienced chisels, those in an area generally between the center of passage and the drilling center of the drill bit surface of bi-central boring drill bits two different directions of movement when drilling. The a direction of movement occurs when the drill bit drills out, and the other direction of movement occurs when the drill bit does that Full diameter drill hole. The chisels that lying in a line with the two center points actually experience exactly opposite directions of movement.

As stated earlier, this has happened in the past serious damage on the chisels caused in this area. The typical solution to this problem has been this area of the area of the drill bit free from chisels allow. Unfortunately can leave this area of chisels at some bi-central drill bits cause the Drilling performance of the drill bit suffers, especially with bi-central drill bits with big differences between the passage diameter and the drilling diameter.

The present invention is based thereon directed the effects of one or more of the above Overcome problems or at least to decrease.

SUMMARY THE INVENTION

In one aspect of the present invention, there is provided a bi-center boring drill bit having a first end bit body adapted to be removably attached to a drill string, a guide portion at a second, opposite end of the bit body, and a reamer portion between the two includes first and second ends. There is a first drilling center of rotation of the guide section and a second through center of rotation of the guide section arranged with a non-zero gap D to the first center of rotation. There is also a first region of the guide section, centered around the first center of rotation, with a radius D, a second region of the guide section, centered around the second center of rotation, with a radius D, and a third region of the guide portion formed by the intersection of the first region and the second region. A cutting element is fastened to the drill bit body within the third region. The cutting element has a first cutting surface, generally perpendicular to the direction of movement of the cutting element around the first center of rotation of the guide section, and a second cutting surface, generally perpendicular to the direction of movement of the cutting element around the second center of rotation of the guide section.

In a second aspect of the present invention a bicentral boring drill bit is provided, the one Drill bit body with a longitudinal axis and a first end that's for it is suitable to be removably attached to a drill pipe, a guide section at a second, opposite end of the bit body and a clearing section between the first and second ends. There is a first drilling center of rotation of the guide section and a second, with a gap D not equal to zero to the first Center of rotation arranged through center of rotation of the guide section. There is a first area of the guide section, centered around the first center of rotation, with a radius D, a second Area of the guide section, centered around the second center of rotation, with a radius D, and a third area of the guide section, by overlapping of the first area and the second area is formed. There are a variety of first chisels in the third area, with super hard cutting surfaces, generally perpendicular to the Direction of movement of the cutting element around the first center of rotation aligned which protrude a distance from the drill bit body. At least a second chisel is inside the drill bit body of the third area and protrudes a distance from the bit body, which is bigger than the projection of the first chisel, with a cutting surface, generally perpendicular to the direction of movement of the second chisel around the second center of rotation aligned.

SHORT DESCRIPTION THE DRAWINGS

The invention is best understood through Reference to the following description in connection with the attached Drawings in which like reference numbers identify like elements, and in which:

1 provides a perspective view of a bi-center boring drill bit according to an embodiment of the present invention,

2A . 2 B and 2C Lateral Perspectives of the Bi-Central Boring Drill Bit from 1 demonstrate,

3 a forehead perspective of the bi-center boring drill bit from 1 shows,

4A a forehead perspective of the bi-center boring drill bit from 1 shows the iris-shaped third area,

4B a simplified forehead perspective of the iris-shaped third portion of a bi-center boring drill bit similar to that of 4A shows,

5 to 7 3 show perspective views of various cutting elements which are mounted in the iris-shaped third region on the bi-central boring drill bit according to the present invention,

8th FIG. 4 is a partial end view of the bicentral boring bit surface showing an alternative bit arrangement according to another embodiment of the present invention;

9 a perspective view of a cutting element of the embodiment of the bi-center boring drill bit of 8th shows,

10 a perspective view of yet another chisel assembly according to another embodiment of the present invention.

While the invention various modifications and alternative forms allows are specific exemplary embodiments thereof are shown in the drawings as examples and are described in detail herein. It should be however understand that the description of specific embodiments contained herein the invention is not intended to limit the particular forms disclosed, on the contrary, the invention is intended to apply to all modifications, Correspondences and alternatives extend within the framework of the Invention fall as defined by the appended claims.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The following are illustrative embodiments described the invention. For the sake of clarity, in this Description does not describe all the features of an actual implementation. It goes without saying can be seen that at the development of such an actual embodiment numerous design-specific Decisions must be made to meet the specific goals of the developer, such as a match with system-dependent and business-related restrictions, that of an execution will vary to another. It will also recognize be that one such development effort can be complicated and time consuming could, but still for Professionals with the usual Knowledge in the field that can benefit from this disclosure Routine task would be.

Turned to the drawings and under be special reference to 1 . 2A . 2 B and 2C now becomes a bicentral boring drill bit 10 with multi-directional chisels according to an embodiment of the present invention. The bi-central boring drill bit 10 has a longitudinal axis 11 on which the drill bit 10 turns, and a drill bit body 12 with a first ending 14 , capable of being attached to a drill string (not shown) around the drill bit 10 drive. According to one embodiment, threads can 16 used to the drill bit 10 to couple to the drill pipe. However, it will be apparent to those of ordinary skill in the art that various other types of fasteners can be used in place of the threads without departing from the scope of the present invention. At a second, opposite end of the bit body 12 there is a guide section 18 of the bi-central boring drill bit 10 , A scraper section, generally by number 20 appears between the first end 14 and the guide section 18 of the bi-central drill bit 10 ,

During operation, the drill bit body 12 rotated over the drill string by an external means while the bi-central boring drill bit 10 is pressed into the material to be drilled. The rotation under load causes elements 24 penetrate the drilled material on the exposed cutting surface and remove the material in a scraping and / or chiseling manner.

According to one embodiment of the present invention, the drill bit body closes 12 internal passages (not shown) that allow pressurized mud from the drilling surface of a plurality of nozzle openings 22 is fed. These nozzle openings 22 give off the mud to the cutting elements 24 to clean and cool when they mesh with the material to be drilled. The mud is also used to transport the drilled material to the surface for disposal.

According to one embodiment, the guide section 18 a section with at least one fluid passage 26 have, which is provided for the reflux of the rinsing sludge. There can also be other fluid passages 26 give that also in the scraper section 20 of the bi-central boring drill bit 10 to be provided.

With special reference to 2 B and 2C are lateral perspectives of the bi-central boring drill bit 10 of the present invention. An important characteristic of the bi-central boring drill bit 10 is his ability to drill a hole 11 into the earth with a diameter of a caliber 13 to drill larger than the inner diameter of the casing 15 or the pipe or other type of guide through which the drill bit 10 what's going on in 2C will be shown.

Another key feature of the bi-center boring drill bit 10 is his ability to cement 17 (and connected devices, not shown) within the casing 15 to drill out as in 2 B shown without the lining ear 15 or the cutting elements 24 of the drill bit 10 to damage.

Referring to 3 will now be a front view of a bi-center boring drill bit 10 of the present invention. The caliber bore diameter, as through the circle 28 is shown by a radius R1 from a first center of rotation 30 of the guide section 18 generated. In this drilling mode, the circular part of the guide section 18 concentric with the diameter 28 his. The cutting elements 24 on the farthest in the radial direction from the first center of rotation 30 distant part of the reamer section 20 actually drill the caliber bore diameter of the borehole 11 as with the number 31 displayed. The scraper section 20 becomes eccentric from the lead section 18 shaped so that only a portion of the borehole wall at a time during operation 11 in contact with the cutting elements 24 which is the final caliber of the borehole 11 to cut.

The bi-central boring drill bit 10 also has a passage diameter, like through the circle 32 indicated, generated by a radius R2 from a second center of rotation 34 of the guide section 18 , The shortest linear distance on the surface of the drill bit between the centers of rotation 30 . 34 is displayed as D. The second center of rotation 34 lies on the center line of the smallest cylinder, which is around the bi-central boring drill bit 10 can be fitted. In order to be effective, the passage diameter through the circle 32 is shown to be smaller than the inner diameter of the casing tube 15 through which the bi-central boring drill bit must pass.

For an optimal service life, the cutting elements 24 on the guide section 18 in a known manner in relation to the direction of scraping by the material to be drilled. This is not a problem with bi-center drill bits that do not drill the cement and associated equipment from the casing. However, if a bicentral boring drill bit drills the cement and associated equipment in the casing, some of the cutting elements can 24 while rotating around the second center of rotation 34 exposed to an inverted cockroach. Reverse scraping often causes the cutting elements to wear quickly 24 and must be avoided.

The cutting elements 24 are typically compact chisels made of polycrystalline diamond or PDC (polycrystalline diamond compact). A PDC typically consists of a paddling pool be diamond or other super hard substance bonded to, but not limited to, a less hard substrate material, typically molded from tungsten carbide. The PDC is then often made by a process known as long substrate bonding on a post or cylinder for insertion into the bit body 12 attached. This PDC type of cutting elements 24 is particularly sensitive to reverse cockroaches, since the stress from reverse cockroaches can easily destroy both the diamond disc bond and the long substrate bond.

In prior art drill bits, the cutting elements are typically configured with a single cutting surface, the cutting surface being properly aligned to cut through material to be drilled when the drill bit is about a first center of rotation, such as the center of rotation 30 , turns. If the bicentral boring drill bit 10 around a second center of rotation, such as the center of rotation 34 , rotates, the cutting surface of the cutting element is not correctly aligned in order to cut optimally through the drilled material. That is, if the cutting element is configured with this single cutting surface, the drill bit is optimally used during drilling around the first center of rotation, but is not optimally arranged to cut material when the drill bit rotates around a second center of rotation. In this particular prior art configuration, the cutting element will undesirably wear out at a faster rate when the drill bit rotates around the center of rotation at which the individual cutting surface of the cutting element is not optimally aligned for cutting material. As a result of the cutting elements wearing at a faster speed, the life of the drill bit is undesirably shortened.

As previously stated, the distance D is the shortest linear distance between the center of rotation 30 and the center of rotation 34 , As in 4A has shown a first area 56 of the guide section 18 , centered around the first center of rotation 30 , a radius D. A second area 58 of the guide section 18 , centered around the second center of rotation 34 , also has the radius D. A third area 60 of the guide section 18 is by overlapping the first area 56 and the second area 58 educated. This iris-shaped area 60 is the critical area where reverse chisel scraping is possible.

Referring to 4B FIG. 5 is a schematic view of the positions of some of the cutting elements of a bi-center boring drill bit similar to that of FIG 4A shown. Three cutting elements 72 . 74 . 76 ( 5 to 7 ) of the present invention are in this iris-shaped area 60 between the drilling center of rotation 30 and the center of rotation of the passage 34 shown.

The chisel 72 has two cutting surfaces 78 . 80 , If the bicentral boring drill bit 10 around the drilling center of rotation 30 is the cutting surface 80 of the chisel 72 properly aligned to along the arrow 82 displayed path to cut. The cutting surface 80 becomes generally perpendicular to the direction of movement of the chisel 72 aligned in this operating mode, parallel to the dashed line 86 that are around the drilling center of rotation 30 passes.

The cutting surface is similar 78 of the chisel 72 properly aligned to along the arrow 84 displayed path to cut when the bi-center boring drill bit 10 around the center of rotation of the passage 34 rotates. The cutting surface 78 becomes generally perpendicular to the direction of movement of the chisel 72 aligned in this operating mode, parallel to the dashed line 88 that around the center of rotation 34 passes.

The chisel 72 can be formed from a material suitable for drilling earth formations. Since the wear rate of cutting elements near the center of the drill bit is generally slow, sintered tungsten carbide may be suitable. It will be appreciated that there is likely to be little wear on the cutting surface during the boring process 78 of the chisel 72 occurs. It would be expected that much more wear on the surface 80 would occur if the drill bit drilled into the earth. If the wear rates are unacceptably high, the chisel can 72 formed from an infiltrated material comprising metal powders such as tungsten carbide mixed with diamond particles and a binder.

The chisel 74 works in a way similar to the chisel 72 , although the chisel 74 , as described later, is intended for much more abrasive drilling than the chisel 72 , The chisel 74 has two cutting surfaces 90 . 92 , If the bicentral boring drill bit 10 around the drilling center of rotation 30 is the cutting surface 90 of the chisel 74 properly aligned to along the arrow 94 displayed path to cut. The cutting surface 90 becomes generally perpendicular to the direction of movement of the chisel 74 aligned in this operating mode, parallel to the dashed line 98 that are around the drilling center of rotation 30 passes.

The cutting surface is similar 92 of the chisel 74 properly aligned to along the arrow 96 displayed path to cut when the bi-center boring drill bit 10 around the center of rotation of the passage 34 rotates. The cutting surface 92 becomes generally vertical to the direction of movement of the chisel 74 aligned in this operating mode, parallel to the dashed line 100 that around the center of rotation 34 passes.

The cutting surface differs to survive heavy, abrasive drilling conditions 92 of the chisel 74 pretty much that of the chisel 72 , A PDC cutting element 102 is on the cutting surface 92 at a short distance 104 from that on the cutting surface 17 of the bi-central boring drill bit 10 exposed end 106 of the chisel 74 appropriate. During the boring phase, the end 106 a low level of wear and tear occur. After drilling, the drill bit will then begin drilling a full diameter hole in the ground. However, under abrasive drilling conditions, even chisels near the center will wear out quickly. Hence the end 106 of the chisel 74 wear out quickly and the PDC element 102 uncover. Once this happens, the chisel will wear out at a rate comparable to other PDC chisels near the center.

In this embodiment, the PDC is chiselled by a process known as long substrate bonding 76 attached. After that, the chisel 76 in the drill bit body 12 used, which gives the PDCs an alternative orientation relative to the center of rotation around which the drill bit is located 10 rotates.

It should be obvious that the chisel 72 and 74 generally different orientations of the cutting surfaces 78 . 80 . 90 . 92 will have to, depending on where they are within the iris-shaped area 60 between the drilling center of rotation 30 and the center of rotation of the passage 34 are located. Although some offset of the cutting surfaces 78 . 80 . 90 . 92 would be tolerated and some commonality of the cutting surface orientations would be for most bi-central boring bits 10 still many different configurations of the chisels 72 and 74 necessary.

An alternative, a conical, chisel 76 for very non-abrasive drilling conditions 7 shown. With the chisel 76 is the side 108 generally conical and ends in a flat top 110 , which is also on the cutting surface 117 exposed. Because this chisel 76 are symmetrical, they can be anywhere within the iris-shaped third range 60 between the drilling center of rotation 30 and the center of rotation of the passage 34 be attached. With this chisel 76 is the cutting edge 112 the intersection of the page 108 and the flat top 110 , Although it's not particularly "sharp", the chisel is 76 suitable for non-abrasive drilling conditions.

In 8th a special drill bit configuration is shown, in which the cutting functions for drilling out and for drilling the full diameter are realized in separate bits. Two cutting surface sections 117 are on the drill bit body 12 shown. It uses a variety of conventional chisels 24 with arrows 114 shown their rotation path around the drilling center of rotation 30 Show. A variety of chisels 116 (shown in 9 ) has cutting surfaces 118 , aligned for drilling, with arrows 119 their rotation path around the center of rotation 34 Show.

The tops 120 the chisel 116 become relatively wider from the bit body 12 aligned than the rest of the chisels 24 on the cutting surface section 117 of the bi-central boring drill bit 10 , Therefore the cutting surfaces 118 the chisel 116 interlock with the boring material and damage the chisel 24 prevent during drilling. Once the boring is complete, the chisels become 16 wear out quickly and allow the chisel 24 drill normally. The operation is therefore practically the same as with the chisel 74 , The chisel 116 can be formed from a material suitable for drilling earth formations. However, it is similar to the chisel 74 , a sintered tungsten carbide material or an infiltrated material, the metal powder such as tungsten carbide mixed with diamond particles and a binder. In this embodiment, the chisel 116 , similar to the chisel 72 . 74 and 76 , aligned as required and then in the drill bit body 12 attached.

An alternative embodiment for the arrangement of the in 8th The boring bit shown is possible if the bit body 12 consists of an infiltrated powder metal matrix material. If this is the case, the chisel 122 as a bump in the matrix of the drill bit body 12 shaped. The cutting surface 118 and the top 120 of the chisel 122 work identically to the chisel 116 , However, since matrix drills are made in a compression molding process, the alignment and fixation of the bit are 122 in the drill bit body 12 unnecessary. The chisel 122 is integrated with the drill bit body. This matrix drill bit design method is well known in the art. Accordingly, the specific details thereof are not disclosed herein to avoid unnecessarily obscuring the present invention.

The embodiments disclosed above are only illustrative since the invention is different but equivalent ways can be modified and implemented that Obviously, to those skilled in the art who use the teachings herein are. About that in addition, no other restrictions are imposed on those shown herein Details of construction or design are intended as in the following claims described.

Claims (9)

Bizentral boring drill bit, which has a drill bit body ( 12 ) with a first end ( 14 ), which is suitable for being detachably attached to a drill pipe, a guide section ( 18 ) at a second, opposite end of the drill bit body and a reamer section ( 20 ) between the first and second ends, the guide portion ( 18 ) a first drilling center of rotation ( 30 ) and a second one with a space D not equal to zero to the first center of rotation ( 30 ) arranged through center of rotation ( 34 ), the guide section ( 18 ) also a first area ( 56 ), centered around the first center of rotation ( 30 ) and with a radius D, a second area ( 58 ), centered around the second center of rotation ( 34 ) and with a radius D, and a third area ( 60 ) by overlapping the first area ( 56 ) and the second area, and characterized by a on the drill bit body within the third area ( 60 ) attached cutting element ( 72 ), the cutting element ( 72 ) a first cutting surface ( 80 ), generally perpendicular to the direction of movement of the cutting element around the first center of rotation ( 30 ) of the guide section, and a second cutting surface ( 78 ), generally perpendicular to the direction of movement of the cutting element around the second center of rotation ( 34 ) of the guide section. A drill bit according to claim 1, wherein the cutting element ( 72 ) consists of a sintered tungsten carbide form. A drill bit according to claim 1, wherein the cutting element ( 72 ) is formed from an infiltrated material comprising metal powder mixed with diamond particles and a binder. The drill bit according to claim 1, wherein a compact bit made of polycrystalline diamond on one of the cutting surfaces of the cutting element ( 72 ) is attached. A drill bit according to claim 1, wherein the cutting element ( 72 ) has a generally conical shape with the first and second cutting surfaces ( 78 . 80 ) are defined by different parts of the generally conical surface of the cutting element. Bizentral boring drill bit, which has a drill bit body ( 12 ) with a longitudinal axis and a first end ( 14 ), which is suitable for being detachably attached to a drill pipe, a guide section ( 18 ) at a second, opposite end of the drill bit body and a reamer section ( 20 ) between the first and second ends, the guide portion ( 18 ) a first drilling center of rotation ( 30 ) and a second one with a space D not equal to zero to the first center of rotation ( 30 ) arranged through center of rotation ( 34 ), the guide section ( 18 ) also a first area ( 56 ), centered around the first center of rotation ( 30 ) with a radius D, a second area ( 58 ), centered around the second center of rotation ( 34 ) with a radius D, and a third area ( 60 ) by overlapping the first area ( 56 ) and the second region, and characterized by a plurality of first chisels ( 24 ), arranged in the third area ( 60 ), with super hard cutting surfaces, generally perpendicular to the direction of movement of the cutting element around the first center of rotation ( 30 ) that protrude a distance from the bit body and at least a second bit ( 116 ) on the drill bit body within the third area ( 60 ) and which projects a distance from the drill bit body that is greater than the protrusion of the first bit ( 24 ), with a cutting surface, generally perpendicular to the direction of movement of the second bit around the second center of rotation. The drill bit of claim 6, wherein the or every second bit ( 116 ) consists of a sintered tungsten carbide form. The drill bit of claim 6, wherein the or every second bit ( 116 ) is formed from an infiltrated material comprising a mixture of metal powders, diamond particles and a binder. A drill bit as claimed in claim 6, wherein the drill bit body is made of an infiltrated powder metal matrix form and is molded around the or every second bit ( 116 ) define.