Reamer for use in drilling operations

#The present invention relates to a drilling apparatus for use in the oil industry. More particularly, the present invention relates to a reamer for use in oil well drilling operations.

#The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.

#Wellbore reamers are known in the field of oil well drilling operations, and are used to open wellbores to allow for smooth operation of a drilling string. For example, U.S. Pat. No. 8,607,900 to Smith discloses a bi-directional reamer. Similarly, European Patent Application No. EP1811124 by Bassal, et al. discloses a similar type of bidirectional reamer.

#These, and further features of the invention, may be better understood with reference to the accompanying specification and drawings depicting the preferred embodiment, in which:

#FIG. 1A is a side view of one embodiment of the present invention;

#FIG. 1B is a plan view of a linear tapered section of FIG. 1, detailing the mounting of cutting elements thereon with back or side rake;

#Referring now to FIG. 1A, FIG. 1A shows a first preferred embodiment of the present invention reamer 10 (hereinafter, “the invented reamer” 10). The invented reamer 10 comprises a reamer body 12 having a first end 14, a second end 16, an interior channel 18, and a plurality of cutting blades 20. The first end 14 of the invented reamer 10 is preferably positioned in use “uphole,” that is, closer to the surface via a borehole (not shown) as known in drilling operations than the second end 16 of the invented reamer 10, which is preferably positioned “downhole” in use, i.e. further from the surface in a borehole. Drilling fluid is pumped downhole through the interior of the drilling string, flows through the axisymmetrically disposed invented reamer 10, through the interior channel 18, and exits the invented reamer 10 at the second end 16. As it returns uphole, the drilling fluid flows over the exterior of the invented reamer 10, providing lubrication and cooling for the cutting blades 20 (hereinafter, “blades” 20).

#Each of the blades 20 comprises a first linear tapered section 22 and a second linear tapered section 23 which rise from the reamer body 12 to the desired cutting radius, and a constant radius helical section 24. The desired maximum outer radius of the helical section 24 is preferably within the range of ⅛ inch to ½ inch smaller than the bore in which the invented reamer 10 is used. The PDC inserts 26 preferably comprise PDC cutting material, but may be composed of any suitable material known in the art, are arrayed along the first and second linear tapered sections 22, 23. The TCI inserts 28 preferably comprise, but are not limited to, tungsten carbide cutters, and are arrayed on the helical sections 24 about a central elongate tool centerline axis 29 (hereinafter, “the tool centerline” 29). The tool centerline 29 extends through the interior channel 18 of the invented reamer 10, through the first end 14 and the second end 16 of the reamer body 12. The blades 20, the PDC inserts 26 (hereinafter, “the PDC inserts” 26), and the inserts 28 (hereinafter, “the TCI inserts” 28) are positioned relative to the tool centerline 29.

#The linear form of first and second linear tapered sections 22 & 23 provide improved cleaning and cooling of the cutting elements arrayed thereon, because circulating fluid is forced directly over these cutting elements. Those of skill in the art will recognize that the arrangement of the PDC inserts 26 and the TCI inserts 28 will allow the invented reamer 10 to ream a borehole regardless of whether the invented reamer 10 is moving uphole or downhole. Additionally, the PDC inserts 26 may be mounted with back rake, side rake, or both to increase cutting efficiency. (See FIG. 1A) Preferably, a plurality of PDC inserts 26, 30 & 32 are mounted with increasing back and side rake (relative to each other) such that a first PDC insert 30 of the plurality of PDC inserts 26, 30 & 32 is mounted closest to the reamer body 12 and a cutter element height linearly increases from the downhole end toward the spiral section and a last PDC insert 32 is of the plurality of PDC inserts 26, 30 & 32 is mounted furthest from the reamer body 12. The plurality of PDC inserts 26, 30 & 32 and the TCI inserts 28 are preferably placed about the tool centerline 29 such that, when viewing the invented reamer 10 from a view point looking along the tool centerline 29, an uninterrupted series of the plurality of PDC inserts 26, 30 & 32 and TCI inserts 28 are presented along the reamer body 12 of the invented reamer 10.