US3205733A - Spiral drill collar and method of manufacture thereof - Google Patents

Spiral drill collar and method of manufacture thereof Download PDF

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US3205733A
US3205733A US317593A US31759363A US3205733A US 3205733 A US3205733 A US 3205733A US 317593 A US317593 A US 317593A US 31759363 A US31759363 A US 31759363A US 3205733 A US3205733 A US 3205733A
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drill collar
bit
drill
manufacture
collar
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US317593A
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Levi F Shiplet
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Texaco Inc
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Texaco Inc
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/22—Rods or pipes with helical structure
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/16—Drill collars

Definitions

  • This invention relates generally to the rotary drilling of wells and specifically to an improved drill collar and the method of manufacture thereof.
  • the bit In rotary drilling, the bit is rotated, with weight being applied to the bit to obtain effective cutting.
  • lengths of drill pipe each normally 30 feet long, are added to form the drill stern, which includes the drill collar, distinct from the drill pipe, adjacent the bit.
  • drilling fluids are provided to the bottom of the well bore where the bit cuttings are picked up by the fluids and brought to the surface through the annulus defined by the well bore and/ or casing and the drill stem.
  • drill collars are made of solid steel billets, usually 30 feet long, to obtain the necessary weight, with the center machined out, e.g. by boring, to the desired inside diameter to define an axial passage.
  • the drill collar is essential to drilling operations because through its weight and rigidity, it helps to keep the drilling of a bore hole straight. Its weight on the bit does not apply compression on the drill pipe and thereby aids in avoiding hole deviation. Frequently, where certain sedimentary formations are abrasive and have low dip angles where fracturing and faulting occur frequently, deviation control becomes difficult.
  • Still another object of the invention is to provide an improved drill collar which will act as a stabilizer and hold more weight on a drill bit.
  • Another object of the invention is to provide an improved drill collar having substantially the same diametral dimension as the drill bit.
  • Still another object of the invention is to provide a novel method of manufacture of a spiral drill collar.
  • FIG. 1 is a longitudinal View, partly in section, of the embodiment of the drill collar constructed in accordance with the present invention, with an intermediate portion thereof broken away;
  • FIG. 2 is a cross sectional view on an enlarged scale of a square billet showing the distortion of the original flat faces after twisting and the extent the original corners are cut away;
  • FIG. 3 is a cross sectional view, on an enlarged scale, taken along line 3-3 of FIGURE 1, of the spiral drill collar as positioned in a well bore.
  • an improved drill collar which fits into a well bore with close clearance to provide stability and to add more weight on the bit thereby improving deviation control and return flow of fluids and increasing drilling speed.
  • the drill collar constructed accord- 3,205,733 Patented Sept. 14, 1965 ing to my invention is disclosed at 10, having an upper end 11 formed into a cylindrical neck with a threaded box 12 formed therein.
  • the lower end 13 is also formed into a cylindrical neck for the threaded pin 14, which receives the bit sub 15 for holding a suitable rotary type bit 16.
  • a pin 17 at the lower end 18 of another drill collar or a drill pipe is joined to box 12 to form the drill stem.
  • the axial passage through the drill collar is disclosed at 19.
  • the cylindrical necks can be formed by swaging or by machining, e.g. by turning, the square billet at the time that the axial passage is formed, e.g. by boring, and either before or after the billet is twisted.
  • FIG. 2 discloses the deformation of the original flat faces of the substantially square billet into concave surfaces, resulting when the square billet is twisted counterclockwise about its longitudinal axis of its 30 foot length to provide substantially a right hand screw thread.
  • the amount of twisting is varied according to the type formation being drilled, the velocity of the drilling fluids in the annulus and the rotating speed of the drill string.
  • the corners of the original square billet, indicated as a, b, c and d, should be machined off to give the desired crosssection dimension and to obtain adequate bearing surface against the well bore, the machining to include grinding, turning and/ or hogging.
  • the rounding of the corners is indicated at A, B, C, D by dotted lines in FIG. 2 and by solid lines in FIG. 3.
  • the size of the billet is chosen so that its diagonal dimension is slightly larger than the well bore diameter or that of the drill bit so that after it is twisted and the corners machined off, the outside diameter will be slightly less than the diameter of the well bore. This will create a packedhole effect and tend to prevent deviation of the hole.
  • FIG. 3 discloses in cross section the filling or packed position of the spiral drill collar in the bore hole, showing the close contact of the bearing surfaces A, B, C, D at the rounded off corners with the well bore, the flutelike flights formed from the flat face surfaces of the square billet serving as an auger for easy removal of the bit cuttings from the bottom of the well bore along with the drilling fluids.
  • the rotation of the spiral drill collar during drilling provides the lifting effect to the drilling fluids and bit cuttings, and the bearing surfaces act as a stabilizer because of the screw effect on the walls of the wall bore, thus reducing the need of separate stabilizers on the drill stem above the bit.
  • conventional drill collars may be used above the improved spiral drill collar, and where formally a conventional round drill collar would permit weights from 2,000 to 5,000 pounds to be applied on the bit, beyond which weights, considerable hole deviation would occur, the spiral drill collar formed by twisting a square billet can carry 20,000 to 40,000 pounds of weight with 8% inch drill pipe without excessive hole deviation. Also, two twists per 30 feet of drill collar is considered usual.
  • the method of forming a spiral drill collar for use with a bit having substantially the same outer diametral dimension comprising in said twisting comprises two counterclockwise complete turns about said longitudinal axis.
  • step (b) of claim 1 where- 'in the forming of the ends into cylindrical necks is accomplished by swaging.
  • step ('c) of claim 1 when said screw threading comprises the external threading of a pin at one end of said member and an internal threading of a box at the other end of said member.
  • step (d) of claim 1 wherein said rounding of theedges is accomplished by a machining process.
  • step (a) of claim 6 wherein said cylindrical necks are formed by machining.
  • step (a) of claim 6 wherein said cylindrical necks are formed by swaging.
  • step (d) of claim 6 wherein opposite necks of said collar are provided respectively with internal and external threading.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Drilling Tools (AREA)
  • Earth Drilling (AREA)

Description

L. F. SHIPLET Sept. 14, 1965 SPIRAL DRILL COLLAR AND METHOD OF MANUFACTURE THEREOF Filed Oct. 21, 1965 United States Patent f 3,205,733 SPIRAL DRILL COLLAR AND METHOD OF MANUFACTURE THEREOF Levi F. Shiple't, Houston, Tex., assignor to Texaco Inc.,
New York, N.Y., a corporation of Delaware Filed Oct. 21, 1963, Ser. No. 317,593 11 Claims. (Cl. 76108) This invention relates generally to the rotary drilling of wells and specifically to an improved drill collar and the method of manufacture thereof.
' In rotary drilling, the bit is rotated, with weight being applied to the bit to obtain effective cutting. As the well bore increases in depth, lengths of drill pipe, each normally 30 feet long, are added to form the drill stern, which includes the drill collar, distinct from the drill pipe, adjacent the bit. Through this drill stern, drilling fluids are provided to the bottom of the well bore where the bit cuttings are picked up by the fluids and brought to the surface through the annulus defined by the well bore and/ or casing and the drill stem.
Conventional drill collars are made of solid steel billets, usually 30 feet long, to obtain the necessary weight, with the center machined out, e.g. by boring, to the desired inside diameter to define an axial passage. The drill collar is essential to drilling operations because through its weight and rigidity, it helps to keep the drilling of a bore hole straight. Its weight on the bit does not apply compression on the drill pipe and thereby aids in avoiding hole deviation. Frequently, where certain sedimentary formations are abrasive and have low dip angles where fracturing and faulting occur frequently, deviation control becomes difficult.
Accordingly, it is an object of the invention to provide an improved drill collar which will increase the penetration rate of drilling without excessive hole deviation.
It is another object of the invention to provide an improved drill collar which will improve the speed of flow of drilling fluids from the bottom to the top of the well bore and also more easily lift bit cuttings and help to keep the drill bit clean.
Still another object of the invention is to provide an improved drill collar which will act as a stabilizer and hold more weight on a drill bit.
Another object of the invention is to provide an improved drill collar having substantially the same diametral dimension as the drill bit.
Still another object of the invention is to provide a novel method of manufacture of a spiral drill collar.
These and other objects, advantages and features of the present invention will become apparent from the following description of the invention and by reference to the accompanying drawings wherein:
FIG. 1 is a longitudinal View, partly in section, of the embodiment of the drill collar constructed in accordance with the present invention, with an intermediate portion thereof broken away;
FIG. 2 is a cross sectional view on an enlarged scale of a square billet showing the distortion of the original flat faces after twisting and the extent the original corners are cut away; and
FIG. 3 is a cross sectional view, on an enlarged scale, taken along line 3-3 of FIGURE 1, of the spiral drill collar as positioned in a well bore.
In accordance with the illustrated embodiment of my invention, there is shown an improved drill collar which fits into a well bore with close clearance to provide stability and to add more weight on the bit thereby improving deviation control and return flow of fluids and increasing drilling speed.
Referring to FIG. 1, the drill collar constructed accord- 3,205,733 Patented Sept. 14, 1965 ing to my invention is disclosed at 10, having an upper end 11 formed into a cylindrical neck with a threaded box 12 formed therein. The lower end 13 is also formed into a cylindrical neck for the threaded pin 14, which receives the bit sub 15 for holding a suitable rotary type bit 16. There is also disclosed the manner in which a pin 17 at the lower end 18 of another drill collar or a drill pipe is joined to box 12 to form the drill stem. The axial passage through the drill collar is disclosed at 19. The cylindrical necks can be formed by swaging or by machining, e.g. by turning, the square billet at the time that the axial passage is formed, e.g. by boring, and either before or after the billet is twisted.
FIG. 2 discloses the deformation of the original flat faces of the substantially square billet into concave surfaces, resulting when the square billet is twisted counterclockwise about its longitudinal axis of its 30 foot length to provide substantially a right hand screw thread. The amount of twisting is varied according to the type formation being drilled, the velocity of the drilling fluids in the annulus and the rotating speed of the drill string. The corners of the original square billet, indicated as a, b, c and d, should be machined off to give the desired crosssection dimension and to obtain adequate bearing surface against the well bore, the machining to include grinding, turning and/ or hogging. The rounding of the corners is indicated at A, B, C, D by dotted lines in FIG. 2 and by solid lines in FIG. 3. The original fiat faces, indicated by dotted lines between the corners, now take the concave shape surfaces as indicated in full lines in FIG. 2. The size of the billet is chosen so that its diagonal dimension is slightly larger than the well bore diameter or that of the drill bit so that after it is twisted and the corners machined off, the outside diameter will be slightly less than the diameter of the well bore. This will create a packedhole effect and tend to prevent deviation of the hole.
FIG. 3 discloses in cross section the filling or packed position of the spiral drill collar in the bore hole, showing the close contact of the bearing surfaces A, B, C, D at the rounded off corners with the well bore, the flutelike flights formed from the flat face surfaces of the square billet serving as an auger for easy removal of the bit cuttings from the bottom of the well bore along with the drilling fluids. The rotation of the spiral drill collar during drilling provides the lifting effect to the drilling fluids and bit cuttings, and the bearing surfaces act as a stabilizer because of the screw effect on the walls of the wall bore, thus reducing the need of separate stabilizers on the drill stem above the bit.
As indicated in FIG. 1, conventional drill collars may be used above the improved spiral drill collar, and where formally a conventional round drill collar would permit weights from 2,000 to 5,000 pounds to be applied on the bit, beyond which weights, considerable hole deviation would occur, the spiral drill collar formed by twisting a square billet can carry 20,000 to 40,000 pounds of weight with 8% inch drill pipe without excessive hole deviation. Also, two twists per 30 feet of drill collar is considered usual.
Thus, there has been disclosed and described a novel and improved drill collar and method of manufacture thereof, which by putting a twist in a square billet, cuts down on the number of separate stabilizers used, eases the return of drilling fluids and cuttings from the bottom of the bore hole to the surface, and by allowing the application of additional weight on the drill bit, shortens the drilling time because of the increased penetration rate and thus reduces the cost of the drilling.
Other modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only 3 such limitations should be imposed as are indicated in the appended claims.
I claim: 1. The method of forming a spiral drill collar for use with a bit having substantially the same outer diametral dimension comprising in said twisting comprises two counterclockwise complete turns about said longitudinal axis.
3Q The'method as defined by step (b) of claim 1, where- 'in the forming of the ends into cylindrical necks is accomplished by swaging. I
4. The method as defined by step ('c) of claim 1, when said screw threading comprises the external threading of a pin at one end of said member and an internal threading of a box at the other end of said member.
5. The method as defined by step (d) of claim 1, wherein said rounding of theedges is accomplished by a machining process.
6. In a method of forming a spiral drill collar of normal length from a substantially square billet, the steps of (a) providing cyindrical necks at the ends of said billet;
(b) forming an axial passage through said billet;
(c) twisting said billet in counterclockwise direction about its longitudinal axis;
((1) providing each of said cylindrical necks with screw threading; and q (e) machining the original edges of said billet to ob- 4 tain a drill collar of the desired dimensions an having spiral grooves.
7. method as defined by step (a) of claim 6, wherein said cylindrical necks are formed by machining.
8. The method as defined 'by step (a) of claim 6, wherein said cylindrical necks are formed by swaging.
9. The method as defined by step (c) of claim 6, wherein said twisting provides two complete turns.
10. The method as defined by step (d) of claim 6, wherein opposite necks of said collar are provided respectively with internal and external threading.
11. The method of forming aspiraldrill collar for use with a bit having substantially the same outer diametral dimension comprising (a) forming the ends of a square hollow member into cylindrical necks; (b) twisting'said-s'quare' hollow member with cylindrical ends about its longitudinal axis; (c) providing said cylindrical necks at each of the ends of said twisted member with screw threading;
and
(d) rounding the original edges of said square hollow member to provide said drill collar with the desired diametral dimension;
GRANVILLE Y. CUSTER, JR., Primary Examiner. CARL W. TQMLIN, Examiner,
1 1/ 26 Great Britain.

Claims (1)

1. THE METHOD OF FORMING A SPIRAL DRILL COLLAR FOR USE WITH A BIT HAVING SUBSTANTIALLY THE SAME OUTER DIAMETRAL DIMENSION COMPRISING (A) TWISTING A SQUARE HOLLOW MEMBER ABOUT ITS LONGITUDINAL AXIS; (B) FORMING THE ENDS OF THE RESULTING TWISTED MEMBER INTO CYLINDRICAL NECKS; (C) PROVIDING SAID CYLINDRICAL NECKS AT EACH OF THE ENDS OF SAID TWISTED MEMBER WITH SCREW THREADING; AND (D) ROUNDING THE ORIGINAL EDGES OF SAID SQUARE HOLLOW MEMBER TO PROVIDE SAID DRILL COLLAR WITH THE DESIRED DIAMETRAL DIMENSION.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177467A1 (en) * 1984-10-01 1986-04-09 Santrade Ltd. Drill steel
US20150233182A1 (en) * 2014-02-14 2015-08-20 Baker Hughes Incorporated Downhole Depth Measurement Using Tilted Ribs
US20220049558A1 (en) * 2020-08-17 2022-02-17 Saudi Arabian Oil Company Reduced differential sticking drilling collar

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1157148A (en) * 1914-10-31 1915-10-19 George T Bond Flexible shaft.
US1188982A (en) * 1915-01-08 1916-06-27 Loran E Nebergall Deep-well auger-stem.
US1409753A (en) * 1919-06-03 1922-03-14 John B Moore Method of making self-lubricating tools
US1543608A (en) * 1924-08-28 1925-06-23 Leidecker Tool Company Method of making spiral auger stems, bits, and substitutes
GB260878A (en) * 1926-05-20 1926-11-11 George Henry Turton Rayner Improvements in, and relating to, hollow drills
US2246418A (en) * 1938-03-14 1941-06-17 Union Oil Co Art of well drilling
US2999559A (en) * 1958-04-04 1961-09-12 Samuel D Boyer Splatter guard for frying pans and the like

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1157148A (en) * 1914-10-31 1915-10-19 George T Bond Flexible shaft.
US1188982A (en) * 1915-01-08 1916-06-27 Loran E Nebergall Deep-well auger-stem.
US1409753A (en) * 1919-06-03 1922-03-14 John B Moore Method of making self-lubricating tools
US1543608A (en) * 1924-08-28 1925-06-23 Leidecker Tool Company Method of making spiral auger stems, bits, and substitutes
GB260878A (en) * 1926-05-20 1926-11-11 George Henry Turton Rayner Improvements in, and relating to, hollow drills
US2246418A (en) * 1938-03-14 1941-06-17 Union Oil Co Art of well drilling
US2999559A (en) * 1958-04-04 1961-09-12 Samuel D Boyer Splatter guard for frying pans and the like

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177467A1 (en) * 1984-10-01 1986-04-09 Santrade Ltd. Drill steel
US20150233182A1 (en) * 2014-02-14 2015-08-20 Baker Hughes Incorporated Downhole Depth Measurement Using Tilted Ribs
US9488006B2 (en) * 2014-02-14 2016-11-08 Baker Hughes Incorporated Downhole depth measurement using tilted ribs
US20220049558A1 (en) * 2020-08-17 2022-02-17 Saudi Arabian Oil Company Reduced differential sticking drilling collar

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