Wear resistant drill pipe

Abstract

Embodiments relate generally to preventing wear to a nominal thickness of a wall of a drill pipe during a downhole operation. A drill pipe may include a first tool joint; a second tool joint; and a tubular section between the first tool joint and the second tool joint, wherein the tubular section comprises a wall with an overall thickness comprising a nominal thickness and a secondary thickness, wherein the secondary thickness is outer to the nominal thickness and is configured to abrade against a wall of the wellbore, thereby reducing the secondary thickness and maintaining the nominal thickness, wherein an ID of each tool joint is less than an ID of the tubular section to accommodate for threaded connectors.

Description

[0001] This application relates to a wear resistant drill pipe.

[0002] During drilling of an oil and / or gas well, drill pipe may be rotated and / or dragged against a wall of a wellbore, causing wall thickness of the drill pipe to erode. This may significantly reduce the life of the drill pipe and may result in high operational costs for the drilling contractor, due to the need to replace the worn drill pipe.

[0003] US3784238 discloses an intermediate drill stem placed between the drill collars and drill pipe of a drill string used in the rotary system of drilling holes in the earth, e.g. oil wells. GB2083856 discloses a drill string member, particularly an intermediate weight drill stem member. US2004195009 discloses a drill string element comprising at least one bearing zone for bearing against the wall of a borehole. US4460202 discloses an intermediate weight drill string member to be used between the drill pipe and the collars in a drill string used in the rotary system of drilling wells. US2013098687 discloses a wellbore tubular and, more specifically, to a wear and buckle resistant drill pipe. US4146060 discloses a drill pipe comprising a tube having tool joints welded to its ends and a wear belt about the tube between its ends, and to method of making such a drill pipe. US2295873 discloses well pipe collars, and is more particularly concerned with metallic pipe collars which are applied for purposes of providing elevator shoulders or for protecting or stiffening the pipe proper. US3080179A discloses a drill pipe having only a part of the tubular section having a larger inner diameter comparing to the inner diameter of the tool joints.

[0004] In accordance with an aspect of the present invention, there is provided a drill pipe as set out in the first of the appending independent claims. In accordance with another aspect of the present invention, there is provided a method as set out in the second of the appending independent claims. Features of various embodiments are set out in the appending dependent claims.

[0005] There is also disclosed herein examples of a drill pipe comprises a first tool joint; a second tool joint; and a tubular section between the first tool joint and the second tool joint, wherein the tubular section comprises a wall with an overall thickness comprising a nominal thickness and a secondary thickness, wherein the secondary thickness is outer to the nominal thickness and is configured to abrade against a wall of the wellbore, thereby reducing the secondary thickness and maintaining the nominal thickness, wherein an ID of each tool joint is less than an ID of the tubular section to accommodate for threaded connectors.

[0006] There is also disclosed herein examples of a drill pipe comprises a first tool joint; a second tool joint; and a tubular section between the first tool joint and the second tool joint, wherein the tubular section comprises a wall with an overall thickness comprising a nominal thickness and a secondary thickness, wherein the secondary thickness is outer to the nominal thickness, wherein the tubular section does not contain mid-tube welds, wherein a weight per length of the drill pipe is less than a weight per length of a heavy weight drill pipe having a similar outer diameter to that of the drill pipe.

[0007] There is also disclosed herein examples of a method for preventing a reduction in a nominal thickness of a drill pipe, comprises positioning a drill pipe in a wellbore, wherein a wall of the drill pipe comprises an overall thickness comprising a nominal thickness and a secondary thickness, wherein the secondary thickness is outer to the nominal thickness; manipulating the drill pipe in the wellbore, causing the drill pipe's outer surface to contact a wall of the wellbore; reducing the secondary thickness due to abrasive forces between the wall of the wellbore and the drill pipe; and maintaining the nominal thickness.

[0008] For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. FIG. 1 illustrates a drill pipe. FIG. 2 illustrates a top view of a drill pipe. FIG. 3 illustrates a drill pipe in a wellbore. FIG. 4 illustrates steps of operating a drill pipe.

[0009] The present subject matter will now be described with reference to the attached figures. Various structures and methods are schematically depicted in the figures for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached figures are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.

[0010] In the following detailed description, various details may be set forth in order to provide a thorough understanding of the various exemplary embodiments disclosed herein. However, it will be clear to one skilled in the art that some illustrative embodiments may be practiced without some of the various disclosed details. Furthermore, features and / or processes that are well-known in the art may not be described in full detail so as not to unnecessarily obscure the disclosed subject matter.

[0011] In horizontal or high angle (e.g., wellbore includes portions deviating from a vertical direction by 45° to 90°) drilling / downhole operations, the drill pipe is rotated or dragged against a wellbore wall. This causes the drill pipe to be abraded by the subterranean formation, causing the drill pipe wall thickness to be reduced. This reduction in drill pipe wall thickness reduces the tensile and torsional capacity of the drill pipe which causes the drill pipe to be downgraded or removed from service. In highly aggressive drilling operations or highly abrasive formations, this significantly reduces the useable life of the drill pipe, and results in high operational costs for the drilling contractor due to the need to replace the worn drill pipe.

[0012] The present disclosure relates generally to drill pipe including a wall with an increased thickness (i.e., an increased outer diameter ("OD")), when compared to standard drill pipe with a nominal thickness. This increased thickness of the wall of the drill pipe described herein (i.e., the wall of the tube or main body / section of the drill pipe) may act as a sacrificial wear area. The thickness of the tube may be increased without reducing the inner diameter ("ID") of the tube (e.g., a reduced ID restricts fluid flow through the drill pipe) or creating mid-tube welds (e.g., welding a larger OD, heavier walled section at mid-tube; mid-tube welds may increase the risk of failure of the drill pipe because the welds may not be able to withstand various forces (e.g., pressure and / or temperature) that may be encountered during drilling). The ID of the drill pipe disclosed herein is equal to or substantially equal to the ID of standard drill pipe (i.e., ID of the tube). Table 1 includes examples of nominal specifications / dimensions for different sized standard (i.e., conventional) drill pipes. Table 1: Nominal Dimensions of Standard Drill PipeOD (inches)ID (inches)Wall Thickness, t 1 , (inches)2 3 / 81.8150.2802 3 / 82.4410.2172 7 / 82.4410.2172 7 / 82.1510.3623 1 / 22.9920.2543 1 / 22.7640.3683 1 / 22.6020.44943.4760.26243.3400.33043.2400.3804 1 / 23.8260.3374 1 / 23.6400.43054.2760.36254.0000.5005 1 / 24.7780.3615 1 / 24.6700.4155 7 / 85.1530.3615 7 / 85.0450.4156 5 / 85.9650.3306 5 / 85.9010.362

[0013] FIG. 1 illustrates drill pipe 100 made of metal or a metal alloy. Drill pipe 100 may include tube 102 fluidly coupling (e.g., in fluid communication) tool joints 104 and 106, as shown. Tube 102 may have an ID 1 that is uniform from first end 108 to second end 110, as shown. Tool joints 104 and 106 may be fluidly coupled to first end 108 of tube 102 and second end 110 of tube 102, respectively. The inner diameters, ID 2 , of tool joints 104 and 106 may be less than ID 1 (e.g., ID S listed in Table 1) to accommodate threaded connectors (e.g., pin 112 of tool joint 106 and box 114 of tool joint 104), as shown. Tube 102 may include a single wall with a nominal thickness, t 1 , (e.g., see Table 1), and a secondary thickness, t 2 , as shown on FIG. 2.

[0014] FIG. 2 is a top view of tube 102 looking down through tube 102 along its longitudinal axis. t 1 is the nominal thickness of wall 200 of tube 102, and t 2 is the thickness of wall 200 that is in excess of t 1 . In other words, the overall thickness of wall 200 includes t 1 and t 2 . The OD is the sum of ID 1 plus t 1 plus t 2 , as shown. t 2 may range from at least 10% of t 1 through 100% of t 1. t 2 is a sacrificial portion of the overall thickness that prevents the nominal wall thickness, t 1 , of tube 102 from being reduced through wear or abrasion due to the drilling environment (e.g., contacting a subterranean formation and / or casing). In other words, t 2 is configured to wear before t 1 , thereby preventing wear to t 1 , and extending the life of tube 102 (and drill pipe 100). As shown, t 1 would not be exposed to a wall of a wellbore. t 2 and t 1 may be made of the same material, and may be subjected to the same heat treatment process, during manufacturing. Table 2 illustrates examples of nominal specifications for different sized standard heavy weight drill pipes ("HWDP"). Table 2: Nominal Specifications of Standard HWDP.OD (inches)Weight Per Foot (pounds)27 / 817.263 1 / 225.653 1 / 223.48429.924 1 / 241.45550.385 1 / 261.635 7 / 857.426 5 / 871.43

[0015] Drill pipe 100 at each OD listed above in Table 2, has a weight per foot that is less than the corresponding weight / per foot for HWDP at the same OD, as listed above in Table 2. Because drill pipe 100 weighs less than a heavy weight drill pipe, there is no need for higher lifting capacities (e.g., drawworks configured to lift heavier weight), as opposed to HWDP which requires higher lifting capacities. Also, the lower weight of drill pipe 100 reduces drag in the wellbore during drilling / downhole operations, thereby causing components of a drilling rig (e.g., top drive, drawworks) to expend less energy to rotate the drill pipe and / or trip the drill pipe, as opposed to HWDP.

[0016] FIG. 3 illustrates drill string 300 including a plurality of drill pipes 302 positioned in a high angle wellbore 304. Each drill pipe 302 may include drill pipe 100, as described herein. As shown, wellbore 304 is a high angle well with a portion 303 that is horizontal. During a drilling or tripping operation, drill pipes 302 may be abraded by wall 306. As described herein, t 2 prevents wear to t 1 , and thus extends the life of drill pipes 302.

[0017] FIG. 4 is a flow chart 400 illustrating steps of operating drill pipe 100 and preventing t 1 from being reduced due to abrasion. At step 402, a drill pipe (e.g., drill pipe 100) is positioned in a wellbore (e.g., wellbore 304), wherein a wall (e.g., wall 200) of the drill pipe comprises an overall thickness comprising a nominal thickness (e.g., t 1 ) and a secondary thickness (e.g., t 2 ), wherein the secondary thickness is outer to the nominal thickness. That is, the secondary thickness is disposed radially outside of the nominal thickness. At step 404, the drill pipe, which is rotated and / or pushed or pulled within the wellbore, is caused to contact a wall (e.g., wall 306) of the wellbore (i.e., manipulating the drill pipe in the wellbore, causing the drill pipe's outer surface to contact a wall of the wellbore). At step 406, the secondary thickness may be reduced / eroded due to abrasive forces between the wall of the wellbore and the drill pipe. At step 408, the nominal thickness is maintained due to the secondary thickness preventing the nominal thickness from being reduced / eroded by the wall of the wellbore.

[0018] The present invention has been described above with references to the particular embodiments disclosed above. It will however be appreciated that the particular embodiments disclosed above may be altered or modified within the scope of the appending claims.

Claims

1. A drill pipe (100) comprising: a first tool joint (104); a second tool joint (106); and a tubular section (102) between the first tool joint (104) and the second tool joint (106), wherein the tubular section (102) comprises a wall with an overall thickness comprising a nominal thickness (t1) and a secondary thickness (t2), wherein the secondary thickness (t2) has an increased outer diameter (OD) compared to the nominal thickness (t1) and is configured to abrade against a wall of a wellbore, thereby reducing the secondary thickness (t2) and maintaining the nominal thickness (t1); characterized in that an inner diameter (ID2) of each tool joint is less than an entire inner diameter (ID1) of the tubular section (102) to accommodate for threaded connectors.

2. The drill pipe of claim 1, wherein the secondary thickness is at least 10% of the nominal thickness.

3. The drill pipe of claim 2, wherein a weight per length of the drill pipe is less than a weight per length of a heavy weight drill pipe having a similar outer diameter to that of the drill pipe.

4. The drill pipe of claim 1, wherein the nominal thickness is not exposed to the wall of the wellbore.

5. The drill pipe of claim 1, wherein the drill pipe does not contain mid-tube welds.

6. The drill pipe of claim 1, wherein the tubular section does not contain mid-tube welds, wherein a weight per length of the drill pipe is less than a weight per length of a heavy weight drill pipe having a similar outer diameter to that of the drill pipe.

7. The drill pipe of claim 1, wherein the nominal thickness is configured to not abrade against the wall of the wellbore due to the secondary thickness preventing contact between the wall of the wellbore and the nominal thickness.

8. The drill pipe of any preceding claim, wherein the inner diameter of the tubular section is uniform.

9. A method for preventing a reduction in a nominal thickness (t1) of a drill pipe (100), the method comprising: positioning the drill pipe (100) in a wellbore, wherein the drill pipe (100) includes a tubular section (102) between a first tool joint (104) a the second tool joint (106), wherein a wall of the tubular section (102) comprises an overall thickness comprising the nominal thickness (t1) and a secondary thickness (t2), wherein the secondary thickness (t2) has an increased outer diameter (OD) compared to the nominal thickness (t1); manipulating the drill pipe (100) in the wellbore, causing the drill pipe's outer surface to contact a wall of the wellbore; reducing the secondary thickness (t2) due to abrasive forces between the wall of the wellbore and the drill pipe (100); and maintaining the nominal thickness (t1); characterized in that an inner diameter (ID2) of each tool joint is less than an entire inner diameter (ID1) of the tubular section (102) to accommodate for threaded connectors (112, 114).

10. The method of claim 9, wherein the secondary thickness is at least 10% of the nominal thickness.

11. The method of claim 10, wherein the drill pipe does not contain mid-tube welds.

12. The method of claim 11, wherein a weight per length of the drill pipe is less than a weight per length of a heavy weight drill pipe having a similar outer diameter (OD) to that of the drill pipe.

13. The method of claim 9, wherein the positioning the drill pipe in the wellbore further comprises positioning the drill pipe in a vertical section of the wellbore.

14. The method of claim 9, wherein the positioning of the drill pipe in the wellbore further comprises positioning the drill pipe in a horizontal section of the wellbore.

15. The method of claim 9, wherein the positioning of the drill pipe in the wellbore further comprises positioning the drill pipe in a section of the wellbore that deviates from a vertical direction by 45 degrees to 90 degrees.

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