The present disclosure generally relates to drill pipe, casing, and tubing used to locate and produce hydrocarbons in a subterranean environment and more specifically to a connection for joining sections of one of drill pipe, casing, and tubing together.
Large portions of hydrocarbon location and production activities involve drilling, pumping, and conduit installation beneath the surface of the earth. In addition, drilling, pumping and conduit installation operations may include water location and distribution. Drilling, pumping, and conduit installation operations may include sewage processing and distribution. Drilling and conduit installation operations may support installation of electrical power transmission lines and telecommunication industry transmission lines. Drilling, pumping, and conduit installation activities often use lengths of pipes. These pipes may be joined together in a variety of different manners. When pipes are joined, there are several considerations. For example, lengths of pipes often extend over long distances. Replacing broken connections may be difficult and timely. Also, drilling activities may require torque to be transmitted across numerous different pipes. Thus, a joint may need to be strong enough to transmit certain levels of torque and resist failure.
Additionally, certain industry standards regarding the diameters of pipe sections exist today. For example, standards exist about the diameters of the inside of pipes. These standards may maintain expected results for a capacity for flow through a string of joined pipes. Standards also exist about the outer diameter of pipes. These standards may maintain expectancies of certain pipes to fit within certain clearances. Thus, there may be limits on the sizes and thicknesses of materials used in the joint sections of the pipes.
Currently available solutions include threaded connections between pipe sections. The threads may be tightened together to form a connection between pipes. However, these types of connections may not transfer the same amount of torque while rotating both to the left and to the right. The threads may become unthreaded when the pipes are rotated in a certain direction and separate. Additional available solutions may involve adding teeth to the ends of joint sections using threaded connections. These teeth may be capable of transferring torque between sections of pipe even while the pipes are rotated in different directions. However, these connections using teeth may not produce desired results for strength in a pipe section.
Accordingly, a need exists for a method and apparatus, which takes into account one or more of the issues discussed above as well as possibly other issues.
According to one embodiment of the present invention, an apparatus comprises a first number of splines located near a first end of a first joint section and a second number of splines located near a second end of a second joint section. The first number of splines extends in an axial direction of the first joint section. The first number of splines spans a circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extend from the base to the tip. The pair of flanks forms an acute angle. The second number of splines extends in an axial direction of the second joint section. The second number of splines spans a circumferential surface of the second joint section. Each of the second number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. The pair of flanks forms an acute angle. Each of the first number of splines is configured to be received between adjacent pairs of splines in the second number of splines as the first end of the first joint section and the second end of the second joint section are joined together to form a connection between the first joint section and the second joint section.
In another embodiment of the present invention, a method for joining sections of piping together is present. The method comprises forming a first number of splines near a first end of a first joint section, forming a second number of splines near a second end of a second joint section, and joining the first end of the first joint section and the second end of the second joint section together to form a connection. The first number of splines extends in an axial direction of the first joint section. The first number of splines spans a circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. The pair of flanks forms an acute angle. The second number of splines extends in an axial direction of the second joint section. The second number of splines spans a circumferential surface of the second joint section. Each of the second number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. The pair of flanks forms an acute angle. Each of the first number of splines is configured to be received between adjacent pairs of splines in the second number of splines.
In another embodiment of the present invention, an apparatus is present for connecting a number of pipes. The apparatus comprises a first number of splines located near a first end of a first joint section, a second number of splines located near a second end of a second joint section, and a coupling for securing the first joint section and the second joint section together. The first number of splines extends in an axial direction of the first joint section. The first number of splines spans an inner circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. Each of the first number of splines has a width configured to decrease as the pair of flanks extends from the base to the tip. The second number of splines extends in an axial direction of the second joint section. The second number of splines spans an outer circumferential surface of the second joint section. Each of the second number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. Each of the first number of splines has a width configured to decrease as the pair of flanks extends from the base to the tip. Each of the first number of splines is configured to be received between adjacent pairs of splines in the second number of splines as the first end of the first joint section and the second end of the second joint section are joined together to form a connection between the first joint section and the second joint section. The pairs of flanks of each of the first number of splines are configured to be wedged between and seated on flanks of adjacent splines of the second number of splines as the connection is formed. The coupling is configured to wedge the first number of splines between adjacent pairs of splines in the second number of splines to a preconfigured force.
The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. The illustrative embodiments, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment of the present invention when read in conjunction with the accompanying drawings, wherein:
With reference now to the figures and particularly with reference to
With reference now to
The different illustrative embodiments recognize and take into account a number of different considerations. For example, the different illustrative embodiments recognize and take into account that it may be desirable to have pipe connections that will resist failure due to the rotational force, such as torque, for example, exerted upon the pipe connections during drilling. The illustrative embodiments recognize that one solution may involve using a shouldered connection. A shouldered connection may involve pipes having threaded ends. The tightening of the threaded ends together causes one pipe end to shoulder or tighten against the other pipe end. However, the illustrative embodiments recognize that the strength of a shouldered connection is a result of the tightening of one shoulder against another shoulder as a result of tightening the threads. Further, when external forces such as torque are exerted upon such a shouldered connection, the threads may yield under the pressure of the external forces.
As used herein “pipe” or “pipes” is/are cylindrical devices that may or may not have a hollow interior. Additionally, the use of the term “pipe” or “pipes” is intended to include without limitation drill pipe, casing, tubing, production tubing, liners, and/or any other cylindrical device suitable for use in wellbores for the production of hydrocarbons. In addition, the use of the term “pipe” or “pipes” is intended to include, without limitation, cylindrical devices for drilling, pumping, and conduit installation operations in support of water location and distribution, sewage processing and distribution, installation of electrical power transmission lines, and installation of telecommunication industry transmission lines. As used herein, “yield”, when referring to an object, means for the object to physically deform as a result of applied forces.
The different illustrative embodiments also recognize and take into account that it may be desirable to have a drill pipe that will not become separated while rotating both to the right and to the left. The different illustrative embodiments recognize that one solution may involve a connection using teeth at an end of one pipe section. These teeth at the end of the one pipe section may be joined with teeth at the end of another section such that rotational force is transferred between the pipes while rotating in either direction. However, the illustrative embodiments recognize that the strength of such a connection is a result of the teeth joined together. Further, these teeth are unsupported as they extend from the ends of the pipes. As a result, these teeth may yield when torque is exerted upon the teeth in this connection. As used herein, teeth, when referring to cylindrical objects, are objects that extend from one of the circular ends of the cylindrical object.
Thus, the illustrative embodiments provide a tapered spline connection for drill pipe, casing and tubing. As used herein, splines, when referring to cylindrical objects, are raised surfaces located on a portion of the cylindrical object's outer surface. In one embodiment, an apparatus comprises a first number of splines located near a first end of a first joint section and a second number of splines located near a second end of a second joint section. The first number of splines extends in an axial direction of the first joint section. The first number of splines spans a circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extend from the base to the tip. The pair of flanks forms an acute angle. The second number of splines extends in an axial direction of the second joint section. The second number of splines spans a circumferential surface of the second joint section. Each of the second number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip. The pair of flanks forms an acute angle. Each of the first number of splines is configured to be received between adjacent pairs of splines in the second number of splines as the first end of the first joint section and the second end of the second joint section are joined together to form a connection between the first joint section and the second joint section.
In another embodiment, the pairs of flanks of each of the first number of splines are wedged between and seated on flanks of adjacent splines of the second number of splines as the first end of the first joint section and the second end of the second joint section are joined together. A coupling is tightened to wedge the first number of splines between adjacent pairs of splines in the second number of splines to a preconfigured force.
In yet another embodiment, tips of each of the first number of splines and each of the second number of splines are configured such that when the connection is formed, a first number of gaps are formed between each tip of the first number of splines and bases of adjacent splines in second number of splines. Additionally, a second number of gaps are formed between each tip of the second number of splines and bases of adjacent splines in first number of splines.
With reference now to
As depicted, first joint section 202 includes first number of splines 206 located near first end 208 of first joint section 202. First number of splines 206 span circumferential surface 210 of first joint section 202. First number of splines 206 also extend in axial direction 211 of first joint section 202. Similarly, second joint section 204 includes second number of splines 212 located near second end 214 of second joint section 204. Second number of splines 212 span circumferential surface 216 of second joint section 204. Second number of splines 212 also extend in axial direction 217 of second joint section 204.
As used herein, a circumferential surface, when referring to objects, is a surface of the object that bounds the object in a circular fashion. For example, a circumferential surface may be a surface corresponding to an inner circumference of a cylinder. A circumferential surface may also be a surface corresponding to an outer circumference of a cylinder. Also used herein, an axial direction when referring to cylindrically shaped objects means a direction substantially parallel to the center axis of the cylindrically shaped object.
In this illustrative embodiment, splines in both first joint section 202 and second joint section 204 have a shape defined by base 218, tip 220, and pair of flanks 222 that extends from base 218 to tip 220. Pair of flanks also form acute angle 224. Each spline in first number of splines 206 is configured to be received between adjacent pairs of splines 226 in second number of splines 212 as first end 208 of first joint section 202 and second end 214 of second joint section 204 are joined together to form connection 228 between first joint section 202 and second joint section 204.
The illustration of connection 200 in
For example, in one illustrative embodiment, first joint section 202 and second joint section 204 may be a tool joint. First joint section 202 and second joint section 204 may be secured to ends of pipes. First joint section 202 and second joint section 204 may also be formed on surfaces of pipes near the end of the pipes. First joint section 202 and second joint section 204 may have different inner diameters and outer diameters. For example, without limitation first joint section 202 and second joint section 204 may be a connection section for pipes having three and a half inch diameters, five inch diameters or any other sizes suitable for use in locating and/or producing hydrocarbons. In other embodiments, splines in first number of splines 206 and second number of splines 212 may be different sizes than each other. Splines in first number of splines 206 and second number of splines 212 may also have different spacing from each other to receive different sizes of splines.
With reference now to
In this illustrative embodiment, first joint section 302 and second joint section 304 may be a tool joint secured to the end of a pipe. Additionally, first joint section 302 and second joint section 304 may be a section of the actual pipe near an end of the pipe. First joint section 302 and second joint section 304 may be machined or otherwise formed onto the actual pipe. In this example, first joint section 302 is a male connector while second joint section 304 is a female connector. In another example, first joint section 302 could be the female connector while second joint section 304 is the male connector. In other examples, first joint section 302 could be an upper or lower joint section relative to second joint section 304.
With reference now to
Plurality of splines 310 are also tapered, meaning that as plurality of splines extend from base 402 towards tip 404 width 416 of plurality of splines 310 decreases. For example, this decrease in width 416 is attributable to spline flank angle 418. Spline flank angle 418 is the angle between pair of flanks 406. Each flank in pair of flanks 406 form flank face angles 419 as each flank extends in radial direction 412 from outer surface 414. Additionally, the radial extension of plurality of splines 310 from outer surface 414 form recessed areas 420 between each of plurality of splines 310.
In this illustrative embodiment, plurality of splines 310 also includes root radii 422 as well as chamfers 424. Root radii 422 are the small edging portions near the interface between plurality of splines 310 and outer surface 414 of first joint section 302. Chamfers 424 are the rounding off or reduction of edge 426 of plurality of splines 310.
With reference now to
In this illustrative embodiment, plurality of splines 312 also includes root radii 516 as well as chamfers 518. Root radii 516 and chamfers 518 may be another example of root radii 422 as well as chamfers 424 in
With reference now to
In this illustrative embodiment, coupling 602 has set of threads 612 formed in inner surface 614. Inner surface 614 of coupling 602 has diameter 616 that is substantially equal to outer diameter 618 of load ring 604. This configuration allows inner surface 614 of coupling 602 to slide in the axial direction around load ring 604. On the other hand, portion 620 of coupling 602 has inner diameter 622 that is substantially smaller than diameter 616 of inner surface 614. Inner diameter 622 is also substantially equal to outer diameter 624 of upper joint section 600. Inner diameter 622 being substantially equal to outer diameter 624 of upper joint section 600 allows coupling 602 to slide around load ring 604 until the point where portion 620 of coupling 602 contacts load ring 604.
As depicted, load ring 604 has set of inner threads 626 that are matched to threads 628 located on upper joint section 600. Set of inner threads 626 allow load ring 604 to be rotated onto threads 628 located on upper joint section 600. Once in place, load ring 604 may be secured to upper joint section 600 and secured using set screws 606. Any number of set screws 606 may be used to lock load ring 604 in place. In alternative embodiments, load ring 604 may be formed on upper joint section 600. Thus, load ring 604 and upper joint section 600 may be the same physical part.
Turning now to
As depicted, upper joint section 702 includes plurality of splines 706 on an outer surface. Similarly, lower joint section 704 includes plurality of splines 707 on an inner surface. In this example, outer diameter 708 of upper joint section 702 is less than inner diameter 709 of lower joint section 704. Outer diameter 708 of upper joint section 702 being less than inner diameter 709 of lower joint section 704 allows end 710 of upper joint section 702 to be placed inside end 712 of lower joint section 704. Outer diameter 708 of upper joint section 702 being less than inner diameter 709 of lower joint section 704 also allows plurality of splines 706 to be received and positioned in recesses between plurality of splines 707. Connection section 700 further includes coupling 714, load ring 716, and retaining ring 718.
In this illustrative embodiment, retaining ring 718 restricts coupling 714 from sliding in an axial direction away from lower joint section 704. Retaining ring 718 is positioned in coupling 714 by engaging threads 720 of retainer ring 718 with threads 722 of coupling 714 when coupling 714 is slid over load ring 716. Once engaged, retaining ring 718 then contacts shoulder 724 of load ring 716 to restrict coupling 714 from sliding away from load ring 716 and lower joint section 704.
With reference now to
In this example, connection section 700 also includes seal 808. Seal 808 is configured to prevent any leakage of fluids from the connection formed between outer surface 802 of upper joint section 702 and inner surface 804 of lower joint section 704. Additionally, filler may be inserted in gap 806 between end 710 of upper joint section 702 and end 712 of lower joint section 704. The filler may be made from a compressible material, such as, for example, without limitation, polymer or urethane material. For example, the filler may be a polymer ring. Fluids may flow through connection section 700 at certain pressures causing possible wear or erosion of components in connection 700. Inserting a filler in gap 806 in connection section 700 may reduce an amount of wear or erosion on end 710 of upper joint section 702 and end 712 of lower joint section 704.
With reference now to
In this depicted embodiment, as coupling 714 is shifted axially towards lower joint section 704, a point is reached where load ring 716 begins to physically resist further axial movement of coupling 714 towards lower joint section 704. At this point, further tightening of coupling 714 on threads 904 begins to force upper joint section 702 and lower joint section 704 further together. Forcing upper joint section 702 and lower joint section 704 together may reduce the axial distance of gaps 806 between upper joint section 702 and lower joint section 704. However, in this example, ends 710 and 712 do not bottom out on surfaces of lower joint section 704 and upper joint section 702. Thus, gaps 806 extending in the axial direction between surfaces of upper joint section 702 and lower joint section 704 remain.
With reference now to
As depicted, each spline of plurality of splines 706 is matched with a recessed area, such as one of recessed areas 512 in
In this depicted embodiment, tightening of coupling 714 forces plurality of splines 706 between and towards plurality of splines 707. Preload in the connection caused by tightening of coupling 714 is generated from the mechanical advantage created by the wedge shape of the flanks of each of each of plurality of splines 706 and 707. As used herein, preload, when referring to a joint connection, refers to the force in a tightened joint connection prior to using the joint connection for its primary function. Preload is a compressive force resulting from two or more surface pairs being forced together during the assembly of a connection. The surfaces in compression can be tightened by any mechanical forces up to the yield strength of the surfaces in contact.
Preload increases the connection stiffness of connection 700 between upper joint section 702 and lower joint section 704. Connection stiffness is the resistance of a connection section to deflecting when external loads are applied to the pipe string. Preload in a connection allows the connection section between pipe joints to respond to forces as if the connection is a continuous section of pipe, because the connection section does not deflect. In this example, preload is applied to connection section 700 as upper joint section 702 and lower joint section 704 are forced together in the axial direction. Additionally, this preload is applied to surfaces of flanks of opposing splines. As gaps 1005 exist, the splines in connection section 700 have not bottomed out. Thus, additional tightening of coupling 714 increases an amount of preload in both the axial and circumferential directions for connection section 700.
In this illustrated embodiment, the angle selected for spline flank angle 1002 and 1004 has a value of about 18 degrees. However, in other advantageous embodiments spline flank angle 1002 and 1004 may be selected from a range between an angle having a value of about 10 degrees and an angle having a value of about 50 degrees. One of ordinary skill in the art would understand that as a spline flank angle approaches 90 degrees the mechanical advantage between opposing splines is reduced. Correspondingly, as a spline flank angle approaches zero degrees, disassembly of the joint sections may become more difficult once forces have been applied to the connection.
The tapered shape of plurality of splines 706 and 707 supplies a number of advantages to connection section 700. First, the tip of each of the splines is narrower than the base of the spline. The narrower tip fits within the larger recessed areas between the splines at an initial engagement stage, such as depicted in
Another advantage which may be attributable to the tapered shape of plurality of splines 706 and 707 is a reduction in the demand for machine tolerances. For example, irregularities may exist in one of more of the splines. One of the flanks of a spline may not be completely planar or the spline flank angle for one of the splines may not be formed to the exact degree desired. As the opposing splines are wedged together, the forces exerted on the splines adjacent to the spline having an irregularity may cause the irregular spline to deform. This deformation of the irregularity as the splines are wedged together may reduce problems caused by the irregularities.
The illustration of connection section 700 in
With reference now to
In this illustrative embodiment, external forces applied to connection section 1100 are resisted by the connection stiffness of male joint section 1104 and female joint section 1106. Additionally, if torque were applied to connection section 1100, hoop stress and hoop tension would be experienced in connection section 1100. Hoop stress, in connection section 1100, is the resistance in male joint section 1104 that arrests retraction and the resistance in female joint section 1106 that arrests swelling as the two joint sections are compressed and/or rotated against each other. Hoop tension in connection section 1100 is the resisting force in the female joint section 1106 wall that provides support and counteracts the hoop stress in the male joint section 1104. For example, the thickness of inner wall 1114 of male joint section 1104 provides support for plurality of splines 1110. Support for plurality of splines 1110 provided by the thickness of inner wall 1114 of male joint section 1104 reduces the tendency for plurality of splines 1110 to retract. Inner wall 1114 also provides an area of support to reduce the exposure of plurality of splines 1110. The area of support provided by inner wall 1114 increases an amount of applied force that plurality of splines 1110 may withstand. In a similar manner, the thickness of outer wall 1116 of female joint section 1106 provides support for plurality of splines 1112. Support for plurality of splines 1112 provided by the thickness of outer wall 1116 of female joint section 1106 reduces the tendency for plurality of splines 1112 to expand. Outer wall 1116 also provides an area of support to reduce the exposure of plurality of splines 1112. The area of support provided by outer wall 1116 increases an amount of applied force that plurality of splines 1112 may withstand.
In addition, inner wall 1114 provides support in the area between the each spline in plurality of splines 1110. The support provided by inner wall 1114 reduces any tendency for splines of plurality of splines 1110 to shear inwardly. Similarly, outer wall 1116 provides support in the area between each spline in plurality of splines 1112. The support provided by outer wall 1116 reduces any tendency for splines of plurality of splines 1112 to shear outwardly. Thus, the cylindrical shape of inner wall 1114 and outer wall 1116 cause axial and torsional forces to be distributed evenly across plurality of splines 1110 and 1112 in connection section 1100. As torque is applied to one joint section, the torque is transferred to the other joint section through the plurality of splines 1110 and 1112 which are supported by the hoop stiffness caused by the cylindrically adjoined flanks. Thus, the overall torsional strength of the connection section 1100 is increased. As used herein, torsional strength, when referring to a connection section, means the amount of torsional forces the connection may withstand before the components of the connection section yield.
As depicted, both plurality of splines 1110 and 1112 have similar flank face angles 1118. In this illustrative embodiment, the angle of flank face angle 1118 is approximately 0 degrees. In this example, flank face angles 1118 are determined relative to the axis of the cylinder of connection section 1100. Flank face angles 1118 are an angle between a first line and a second line. The first line is perpendicular to the axis and intersects the spline flank at a point along the radial midpoint of the flank face. The second line is a line that is tangential to the point along the radial midpoint of the flank face that intersects with the first line. As depicted in
However, flank face angles 1118 may vary as the cross section of connection 1100 is shifted axially. For example, near the bases of splines in plurality of splines 1110 the flank face angle may be different than the flank face angle near the bases of splines in plurality of splines 1112. As depicted, in
Overall, flank face angle 1118 may be selected from a range between an angle having a value of about negative 30 degrees and an angle having a value of about 30 degrees. Additionally, flank face angle 1118 may vary in connection section 1100 from a range between an angle having a value of about negative 30 degrees and an angle having a value of about 30 degrees. Persons skilled in the art recognize and take note that an angle approaching 90 degrees may cause male joint section 1104 and female joint section 1106 to slip rotationally as torque load increases 1100. Persons skilled in the art recognize and take note that an angle approaching negative 30 degrees may cause the materials of the joint section to yield in response to certain levels of torque or other forces applied to connection section 1100.
The illustration of connection section 1100 in
With reference now to
In this illustrative embodiment, first joint section 1202 has plurality of splines 1212, while second joint section 1204 has plurality of splines 1214. Plurality of splines 1214 includes at least one spline, spline 1216, that is a different size than other splines in plurality of splines 1214. On the other end of pipe 1200, recessed area 1218 between splines in plurality of splines 1212 is larger than other recessed areas between splines in plurality of splines 1212. As depicted, both spline 1216 and recessed area 1218 are substantially centered on scribe line 1220. Scribe line 1220 is a reference line that extends from first end 1204 to second end 1208 on pipe 1200. In this example, centering both spline 1216 and recessed area 1218 along scribe line 1220 provides a particular orientation for pipe 1200.
In this illustrated embodiment, spline 1216 is larger than other splines in plurality of splines 1214. However, in other embodiments, splines 1216 may be smaller than other splines in plurality of splines 1214. In another example, splines 1216 may be tapered at a different angle than other splines in plurality of splines 1214. Still further, the different spline may be a part of one first joint section 1202 and any number of different sized splines may be used.
With reference now to
Connection section 1300 is configured such that spline 1308 may only be fit into and be received by recessed area 1306 when upper joint section 1302 and lower joint section 1304 are fully engaged. Configuring connection section 1300 such that spline 1308 may only be fit into and be received by recessed area 1306 when upper joint section 1302 and lower joint section 1304 are fully engaged allows connection section 1300 to maintain a particular orientation as illustrated by scribe line 1310. Further, maintaining this particular orientation of connection section 1300 may allow an entire string of drill pipe to maintain a selected and particular orientation. Additional methods and apparatuses for maintaining orientation of pipes are disclosed in U.S. Pat. No. 5,950,744 entitled “Method and Apparatus for Aligning Drill Pipe and Tubing,” incorporated herein by reference.
With reference now to
With reference now to
With reference now to
With reference now to
The illustrations of electrical wiring and electrical connections
With reference now to
With reference now to
Female joint section 1900 may be joined with a male joint section, such as male joint section 1800 in
While spline 1802 in
The illustrations of electrical connections and splines having substantially parallel sides in
The description of the different embodiments of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention the practical application to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
This application is a divisional of U.S. patent application Ser. No. 12/695,569, filed Jan. 28, 2010, the entire disclosure of which is incorporated by reference herein.
Number | Date | Country | |
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Parent | 12695569 | Jan 2010 | US |
Child | 14069824 | US |